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gigmes.

ACL - Articles dans des revues à comité de lecture

306 références.
2019

  • Astolfi, P.; Clement, J. - L.; Gigmes, D.; Armeni, T.; Carloni, P.; Greci, L. Redox Report 2019, 24 (1), 56-61.
    Résumé : Objectives: Coenzyme Q(10), incorporated in DOPC lyposomes or naturally present in liver bovine mitochondria or in human blood plasma, was reacted with nitrogen dioxide (NO2)-N-center dot or with a (NO)-N-center dot/(NO2)-N-center dot mixture. Methods and Results: The reaction course was monitored by Electron Paramagnetic Resonance (EPR) spectroscopy and in all cases the formation of a di-tert-alkyl nitroxide was observed, deriving from the addition of (NO2)-N-center dot to one of the double bonds, most likely the terminal one, of the isoprenic chain. The rate constant for nitroxide formation was also determined by EPR spectroscopy and an initial rate of ca. 7 x 10(-8 )M s(-1) was obtained.

  • Baron, M.; Rakotorinina, M. - D.; El Assil, M. I.; Guillaneuf, Y.; Gigmes, D.; Siri, D.; Gaudel-Siri, A.; Flat, J. - J.; Quinebeche, S.; Cassagnau, P.; Beyou, E. Materials Today Communications 2019, 19, 271-276.
    Résumé : For the first time, the melt radical grafting of diethylmaleate (DEM) and maleic anhydride (MA) onto oligoamide-11 (OA11) and polyamide-11 (PA11) was performed in presence of new acyloxyimide derivatives in the temperature range 190 degrees C-250 degrees C in an autoclave and a mini-extruder, respectively. The DEM grafting degree was studied as a function of reaction temperature, the DEM concentration, the acyloxyimide concentration and its chemical structure. The degree of grafting of DEM was determined by H-1 NMR and we obtained a DES (diethylsuccinimate) functionalization degree (FD) as high as 9 mol% onto OA11 when using tBu-NAPI as Habstractor at 230 degrees C. However, the transposition of this grafting reaction at a pilot scale did not permit to obtain such a high DES FD while the morphological study of PA11/EVOH blends with the grafted copolymer did not significantly improve the adhesion between the two phases.

  • Bonardi, A. H.; Bonardi, F.; Dumur, F.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Macromolecular Rapid Communications 2019, 1900495.
    Résumé : Photo-induced thermal polymerization upon near-infrared (NIR) light irradiation has been reported in the literature. In this approach, a component able to convert the NIR light into heat must be used in combination with a thermal initiator to initiate the free-radical polymerization of (meth)acrylates. In recent studies, some absorbers have been presented as very efficient heat generators (called heaters). In the present work, different fillers are investigated as heaters and compared to organic NIR absorbers. An alkoxyamine (e.g., BlocBuilder-MA) is used as thermal initiator and is dissociated by the heat generated by the NIR photoexcitation of the fillers. In the present work, several fillers are examined: graphene oxide, graphene nanoplatelets, multi-walled carbon nanotubes, and silicon carbide. Due to the energy of the photon delivered, NIR light curing is challenging but offers several advantages compared to visible light. The most interesting feature is the deeper penetration of the light inside the photocurable resin, enabling the polymerization of thick samples. Parallel to this, incorporation of fillers in resins allows unique access to composites through photothermal polymerization of (meth)acrylates. Three different wavelengths of irradiation have been studied: 785, 940, and 1064 nm.

  • Bonardi, A.; Bonardi, F.; Noirbent, G.; Dumur, F.; Dietlin, C.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Polymer Chemistry 2019, 10 (47), 6505-6514.
    Résumé : In this article, near-infrared dyes of different structures have been investigated as new photoinitiators/photosensitizers for the free radical polymerization (FRP) of methacrylates upon Near InfraRed (NIR) light exposure using a laser diode @785 nm, @940 nm and @1064 nm. Interestingly, the use of squaraine, squarylium, boron-pyrromethene and porphyrin derivatives as efficient photoinitiators is clearly highlighted. These dyes are used in combination with an iodonium salt and a phosphine. Additionally, a thermal initiator can be added to the resin to take advantage of the photothermal effect, i.e., to the heat release during the polymerization process, so that polymerization kinetics could be greatly improved compared to the pure photochemical mode. These dyes can be proposed as alternatives to the well-established cyanine dyes, more commonly used for the photopolymerization of (meth)acrylates under NIR light.

  • Bonardi, A. - H.; Zahouily, S.; Dietlin, C.; Graff, B.; Morlet-Savary, F.; Ibrahim-Ouali, M.; Gigmes, D.; Hoffmann, N.; Dumur, F.; Lalevee, J. Catalysts 2019, 9 (8), 637.
    Résumé : Photopolymerization processes, and especially those carried out under visible light, are more and more widespread for their multiple advantages compared to thermal processes. In the present paper, new 1,8-naphthalimide derivatives are proposed as photoinitiators for free-radical polymerization upon visible light exposure using light-emitting diodes (LEDs) at 395, 405, and 470 nm. These photoinitiators are used in combination with both iodonium salts and phosphine. The synthesis of these compounds as well as their excellent polymerization initiation ability for methacrylate monomers are presented in this article. A full picture of the involved chemical mechanisms is also provided thanks to photolysis, radical characterization, and redox measurements.

  • Bonnevide, M.; Jimenez, A. M.; Dhara, D.; Phan, T. N. T.; Malicki, N.; Abbas, Z. M.; Benicewicz, B.; Kumar, S. K.; Couty, M.; Gigmes, D.; Jestin, J. Macromolecules 2019, 52 (20), 7638-7645.
    Résumé : We control nanoparticle (NP) dispersion by leveraging the entropic and enthalpic effects associated with mixing silica NPs grafted with polyisoprene (PI) chains into matrices of varying degrees of chemical dissimilarity. Previous work in this area has primarily focused on entropic factors alone, and hence, this work represents a significant advance over the current state-of-the-art. We show using a combination of transmission electron microscopy/small- angle X-ray scattering that mixing grafted particles with PI matrices of identical microstructure yields dispersion states as found in the literature for such entropic systems. However, replacing the PI matrix chains with dissimilar matrices leads to an introduction of enthalpic interactions that, in some cases, can drastically change the resulting morphology. In particular, while slightly different PI microstructures for the grafted and free chains only yield moderated differences, using styrene-butadiene copolymers as a matrix leads to a completely different behavior. In the last case, phase separation becomes more likely with the increasing graft length, while the PI system (whose behavior is dominated by entropic factors) shows the opposite behavior. Tuning the relative importance of enthalpic versus entropic factors is thus another tool in controlling the self-assembled structure of NPs, which gives rise to enhanced macroscopic properties in the composite.

  • Garra, P.; Brunel, D.; Noirbent, G.; Graff, B.; Morlet-Savary, F.; Dietlin, C.; Sidorkin, V. F.; Dumur, F.; Duche, D.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Polymer Chemistry 2019, 10 (12), 1431-1441.
    Résumé : Ferrocene-based photoredox catalysis is proposed here for the first time. Aryl radicals generated from a Fe(II)*/Ar2I+ reaction can be used as initiating species for efficient free radical photopolymerization of methacrylate resins. Remarkably, these photoredox catalysts can also be used for redox free radical polymerization (without light) in combination with ammonium persulfate for unique access to dual cure (photochemical/thermal redox) systems. The addition of a third component (amine, phosphine or vitamin C reducing agents) enables the regeneration of the catalysts and greatly enhances the radical generation. The motivation with these dual cure systems is to develop orthogonal chemistries where a latent redox polymerization (without light) is able to cure any thickness of polymers (or composite) in combination with fast photopolymerization processes in the irradiated areas. Chemical mechanisms will be discussed in detail using cyclic voltammetry, electron spin resonance spin trapping (ESR-ST), UV-vis-NIR spectroscopy, free energy calculations and molecular modeling at the density functional theory (DFT) level. This study represents, to the best of our knowledge, the first photochemically active iron catalysts that are also efficient in thermal redox catalysis.

  • Garra, P.; Dietlin, C.; Morlet-Savary, F.; Dumur, F.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Progress in Polymer Science 2019, 94, 33-56.
    Résumé : Redox polymerizations are of huge importance throughout academic and industrial polymer science. Many authors propose the reaction of reducing (Red) and oxidizing (Ox) agents to accelerate/initiate radical or cationic polymerizations. As a result of activation energies typically below 80 kJ/mol, such reactions can occur under mild conditions, e.g., at room temperature, with reduced energy consumptions and robust in applications, such as the fabrication of composites. However, a clear definition of redox polymerization can only be found in reviews dealing with redox free radical polymerizations (FRP) published twenty years ago (or more). Therefore, a fresh and broader update is provided here for more recent work. The concepts involved when the Redand Oxagents (constituting the redox initiating system) are mixed under mild conditions are presented, followed by a discussion of the redox FRP initiating systems in bulk. Initiating systems dealing with the redox cationic polymerization (CP) are reviewed, and parallels between conventional FRP/CP and controlled polymerizations, in which redox systems are used, is provided. Many redox agents are useful in both modes. Finally, dual-cure (redox/photochemical; redox dual FRP/CP) systems is presented and selected applications are reviewed. Altogether, the state of the art for redox two-component polymerizations is provided, along with some perspectives. (C) 2019 Elsevier B.V. All rights reserved.

  • Gaudel-Siri, A.; Marchal, C.; Ledentu, V.; Gigmes, D.; Siri, D.; Charles, L. European Journal of Mass Spectrometry 2019, 25 (2), 229-238.
    Résumé : The dissociation behavior of two stable nitroxides, namely 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO center dot) and N-tert-butyl-1-diethylphosphono-2,2-dimethylpropyl nitroxide (SG1(center dot)), subjected as protonated molecules to collisional activation was investigated using a combination of different mass spectrometry experiments and theoretical calculations. Elemental composition of reaction products was derived from accurate mass data measured in high resolution tandem mass spectrometry experiments, primary fragments were distinguished from secondary ions based on both breakdown curves and MS3 data, and H/D exchange experiments were performed to support proposed structures. Postulated fragmentation pathways were then studied in terms of energetic, using the standard B3LYP/6-31G(d) method. While protonation of TEMPO center dot mainly occurred on the oxygen atom of the nitroxyl function, a series of protomers were found for SG1(center dot) with the adducted proton preferentially located onto the P=O group of this phosphorylated species. For both protonated nitroxides, major product ions measured in tandem mass spectrometry arose from reactions occurring at low energy costs via elimination of radical species. Formation of secondary fragments that were detected with low abundance when raising the activation level of both precursor ions could be rationalized with pathways proceeding via high energy transition states.

  • Guerineau, V.; Rollet, M.; Viel, S.; Lepoittevin, B.; Costa, L.; Saint-Aguet, P.; Laurent, R.; Roger, P.; Gigmes, D.; Martini, C.; Huc, V. Nature Communications 2019, 10, 113.
    Résumé : Calixarenes are cyclic oligomers obtained by condensation of suitable p-functionalised phenols with formaldehyde, usually allowing for the synthesis of the well known small calixarenes (including up to eight phenolic subunits). We report here the discovery of much larger members of this family, exhibiting sizes up to 90 phenolic subunits: the giant calixarenes. These macrocycles are obtained according to simple, easily scalable processes, in yields up to 65%. We show that the formation of these giant macrocycles is favored by an oxygencontaining-group at the para-position of the starting phenol, high concentrations of heavy alkaline bases (rubidium or cesium hydroxides) and long reaction times. A mechanism is proposed to rationalize these observations. These giant macrocycles can also be obtained in the quasi-solid state, opening interesting perspectives in the field of calixarenes chemistry. Along with their intrinsic fundamental interest, these objects are also opening interesting applicative potentialities.

  • Le, D.; Dilger, M.; Pertici, V.; Diabate, S.; Gigmes, D.; Weiss, C.; Delaittre, G. Angewandte Chemie (International ed. in English) 2019, 58 (14), 4725-4731.
    Résumé : We report the straightforward, time-efficient synthesis of radical core-shell nanoparticles (NPs) by polymerization-induced self-assembly. A nitroxide-containing hydrophilic macromolecular precursor was prepared by ring-opening metathesis copolymerization of norbornenyl derivatives of TEMPO and oligoethylene glycol and was chain-extended in situ with norbornene in ethanolic solution, leading to simultaneous amphiphilic block copolymer formation and self-assembly. Without any intermediate purification from the monomers to the block copolymers, radical NPs with tunable diameters ranging from 10 to 110 nm are obtained within minutes at room temperature. The high activity of the radical NPs as chemoselective and homogeneous, yet readily recyclable catalysts is demonstrated through oxidation of a variety of alcohols and recovery by simple centrifugation. Furthermore, the NPs show biocompatibility and antioxidant activity in vitro.

  • Mokbel, H.; Anderson, D.; Plenderleith, R.; Dietlin, C.; Morlet-Savary, F.; Dumur, F.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Progress in Organic Coatings 2019, 132, 50-61.
    Résumé : This investigation presents the use of a photoredox catalyst "G1" as a photoinitiating system for free radical/cationic hybrid polymerization under mild irradiation conditions. The G1 system (G1/iodonium salt/N-vinylcarbazole), can simultaneously initiate the free radical and cationic polymerization reactions upon exposure to a visible (405 nm) light from a Light Emitting Diode (LED) source. The multicomponent G1 system is able to simultaneously generate radical and cationic species through a catalytic photoredox process. The curing of thin samples (25 mu m), thick samples (1.4 mm) as well as the manufacture of hybrid system/glass fibers composites ( 2 to 4 mm thickness) was realized and the influence of the ratio of cationic/radical monomer blends on the polymerization kinetics was studied. The use of G1 in visible light photoinitiating system for the access to composites and 3D printing experiments was particularly outlined. G1 was also shown to have low levels of migration from the cured materials. When compared to reference materials ("F1", a similar copper complex and an anthracene derivative, dibutoxy anthracene), G1 showed better polymerization efficiency. The initiation efficiency was investigated through the real-time Fourier transform infrared (RT-FTIR) spectroscopy and optical pyrometry. Dynamical Mechanical Analysis has been used to determine the glass temperature transition of the cured hybrid system as a complementary technique.

  • Pertici, V.; Pin-Barre, C.; Rivera, C.; Pellegrino, C.; Laurin, J.; Gigmes, D.; Trimaille, T. Biomacromolecules 2019, 20 (1), 149-163.
    Résumé : Injectable hydrogels are promising platforms for tissue engineering and local drug delivery as they allow minimal invasiveness. We have here developed an injectable and biodegradable hydrogel based on an amphiphilic PNIPAAm-b-PLA-b-PEG-b-PLA-b-PNIPAAm pentablock copolymer synthesized by ring-opening polymerization/nitroxide-mediated polymerization (ROP/NMP) combination. The hydrogel formation at around

  • Phan, T. N. T.; Issa, S.; Gigmes, D. Polymer International 2019, 68 (1), 7-13.
    Résumé : Nanostructured block copolymer electrolytes (BCEs) based on poly(ethylene oxide) (PEO) are considered as promising candidates for solid-state electrolytes in high energy density lithium metal batteries (LMBs). Because of their self-assembly properties, they confer on electrolytes both high mechanical strength and sufficient ionic conductivity, which linear PEO cannot provide. Two types of PEO-based BCEs are commonly known. There are the traditional ones, also called dual-ion conducting BCEs, which are a mixture of block copolymer chains and lithium salts. In these systems, the cations and anions participate in the conduction, inducing a concentration polarization in the electrolyte, thus leading to poor performances of LMBs. The second family of BCEs are single-lithium-ion conducting BCEs (SIC-BCEs), which consist of anions being covalently grafted to the polymer backbone, therefore involving conduction by lithium ions only. SIC-BCEs have marked advantages over dual-ion conducting BCEs due to a high lithium ion transference number, absence of anion concentration gradients as well as low rate of lithium dendrite growth. This review focuses on the recent developments in BCEs for applications in LMBs with particular emphasis on the physicochemical and electrochemical properties of these materials. (c) 2018 Society of Chemical Industry

  • Pigot, C.; Noirbent, G.; Bui, T. - T.; Peralta, S.; Gigmes, D.; Nechab, M.; Dumur, F. Materials 2019, 12 (8), 1342.
    Résumé : A series of ten push-pull chromophores comprising 1H-cyclopenta[b]naphthalene-1,3(2H)-dione as the electron-withdrawing group have been designed, synthesized, and characterized by UV-visible absorption and fluorescence spectroscopy, cyclic voltammetry and theoretical calculations. The solvatochromic behavior of the different dyes has been examined in 23 solvents and a positive solvatochromism has been found for all dyes using the Kamlet-Taft solvatochromic relationship, demonstrating the polar form to be stabilized in polar solvents. To establish the interest of this polyaromatic electron acceptor only synthesizable in a multistep procedure, a comparison with the analog series based on the benchmark indane-1,3-dione (1H-indene-1,3(2H)-dione) has been done. A significant red-shift of the intramolecular charge transfer band has been found for all dyes, at a comparable electron-donating group. Parallel to the examination of the photophysical properties of the different chromophores, a major improvement of the synthetic procedure giving access to 1H-cyclopenta[b]naphthalene-1,3(2H)-dione has been achieved.

  • Pigot, C.; Noirbent, G.; Peralta, S.; Duval, S.; Nechab, M.; Gigmes, D.; Dumur, F. Helvetica Chimica Acta 2019.
    Résumé : An unprecedented nucleophilic addition of piperidine on an electron acceptor, namely, 2-(3-oxo-2,3-dihydro-1H-cyclopenta[b]naphthalen-1-ylidene)malononitrile is reported. This unexpected behavior was observed during the synthesis of push-pull dyes using the classical Knoevenagel reaction. To overcome this drawback, use of diisopropylethylamine (DIPEA) enabled to produce the expected dyes PP1 and PP2. The optical and electrochemical properties of the different dyes were examined. Theoretical calculations were also carried out to support the experimental results. To evidence the higher electron-withdrawing ability of this electron acceptor, a comparison was established with two dyes (PP3 and PP4) comprising its shorter analogue.

  • Rakotonirina, M. D.; Baron, M.; Siri, D.; Gaudel-Siri, A.; Quinebeche, S.; Flat, J. - J.; Gigmes, D.; Cassagnau, P.; Beyou, E.; Guillaneuf, Y. Polymer Chemistry 2019, 10 (31), 4336-4345.
    Résumé : Acyloxyimides as a new H-abstracting agent have been developed for the radical grafting of maleic anhydride (MA) onto polyethylene in the melt state. Their model decomposition in DMSO-d6 as well as in tetradecane that mimics polyolefins was performed. These studies confirmed first the complete decomposition of N-acetoxyphthalimide (NAPI) in 1 hour at 180 degrees C by a N-O bond dissociation mechanism and also the patching of the produced macroradicals by the phthalimide group. The reaction was then performed in a mini-extruder at 190-250 degrees C and the hydrogen abstraction ability of N-acyloxyphthalimide (NAP)-, N-acyloxynaphthalimide (NANP)- and N-acyloxysuccinimide (NAS)-based derivatives was demonstrated. Optimal experimental conditions were determined by varying the initial MA content and the degree of grafting of MA was quantified by infrared spectroscopy. The MA grafting degree was as high as 2.98 wt% when using tBu-NAP as the H-abstracting agent at 230 degrees C with only a slight modification of the PE chain structures as proved by rheological experiments while the use of a peroxide (L101) led to a lower grafting degree (1.9 wt%) and a cross-linking of the polymer chains, confirmed by the three-five fold higher complex viscosity.

  • Rolere, S.; Monge, S.; Rakotonirina, M. D.; Guillaneuf, Y.; Gigmes, D.; Robin, J. - J. Journal of Polymer Science Part a-Polymer Chemistry 2019, 57 (2), 120-129.
    Résumé : Chemical modification of poly(lactic acid) (PLA) with N-acetoxy-phthalimide (NAPI) was performed in the melt by reactive extrusion, without using any peroxide initiator. The aminyl and nitroxide radicals produced from the NAPI thermal degradation, were, respectively, used (a) to create PLA macroradicals, and (b) to functionalize the PLA samples through nitroxide radical coupling. Depending on the extrusion temperature and the initial NAPI concentration, grafting rates up to 0.24 mol % were measured, modifying the PLA optical properties. This study represents an original new way of modification of PLA without the use of conventional peroxide initiators. Indeed, the undesirable side reactions (PLA branching or crosslinking) usually observed when using peroxides to initiate the radical grafting of PLA were avoided when using NAPI. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 120-129

  • Rolere, S.; Monge, S.; Rakotonirina, M. D.; Guillaneuf, Y.; Gigmes, D.; Robin, J. - J. Journal of Polymer Science Part a-Polymer Chemistry 2019, 57 (8), 917-928.
    Résumé : Radical grafting of poly(lactide) (PLA) during postpolymerization reactive extrusion is usually done with peroxide initiation, leading to undesirable side reactions (branching or crosslinking) and to difficulties to control the process parameters as well as the final macromolecular structure. The use of N-acetoxy-phthalimide (NAPI) was investigated as an alternative to peroxides for the functionalization in the melt of PLA with N-phenylmaleimide (PhM) monomer. The use of NAPI was found to lead to similar grafting rates in comparison to peroxides, with a better control of the PLA macromolecular structure, due to the formation of nitroxide radicals that combine with the produced macroradicals. Also, the grafting site on PLA backbone was identified after hydrolysis of grafted PLA. Above an optimal PhM concentration, homopolymerization of the monomer was also highlighted. (c) 2019 Wiley Periodicals, Inc.

  • Tesfaye, A. T.; Dumur, F.; Gigmes, D.; Maria, S.; Monconduit, L.; Djenizian, T. Scientific Reports 2019, 9, 4301.
    Résumé : The high failure strain of thermoplastic elastomers (TPEs) is a very desirable feature for rechargeable Li-ion batteries by improving the lifetime of high specific capacity anode materials that undergo mechanical fractures induced by large volume variations. In this work, poly(styrene-b-2-hydroxyethyl acrylate) called PS-b-PH EA was synthesized by a nitroxide meditated polymerization method. Owing to the use of a specific polystyrene macroinitiator (SG1), a suitable TPE copolymer with long hydroxyethyl acrylate blocks to ensure good mechanical properties is obtained for the first time. We show that the electrochemical properties of the PS-b-PHEA-coated SnSb anode are drastically improved by suppressing the crack formation at the surface of the electrode. Indeed, electrochemical characterization revealed that a high and stable gravimetric capacity over 100 cycles could be achieved. Moreover, excellent capacity reversibility was achieved when cycled at multiple C-rates and fast kinetics confirming the strong protection role of the polymer. The advanced chemical and mechanical properties of PS-b-PHEA open up promising perspectives to significantly improve the electrochemical performance of all electrodes that are known to suffer from large volume variations.

  • Tran, J.; Pesenti, T.; Cressonnier, J.; Lefay, C.; Gigmes, D.; Guillaneuf, Y.; Nicolas, J. Biomacromolecules 2019, 20 (1), 305-317.
    Résumé : 2-Methylene-1,3-dioxepane (MDO) and different vinyl ether (VE) monomers were successfully copolymerized by free-radical radical ring-opening copolymerization (rROP) to yield P(MDO-co-VE) copolymers with M-n = 7 000-13 000 g.mol(-1) and high molar fractions of MDO (F-MDO = 0.7-0.9). By using VE derivatives of different aqueous solubilities or by grafting PEG chains onto the copolymers by "click" chemistry via azide-containing

  • Villotte, S.; Gigmes, D.; Dumur, F.; Lalevee, J. Molecules (Basel, Switzerland) 2019, 25 (1).
    Résumé : Iodonium salts are well established photoacid generators, cationic photoinitiators, as well as additives commonly used in photoredox catalytic cycles. However, as a strong limitation, iodonium salts are characterized by low light absorption properties for lambda > 300 nm so that these latter cannot be activated with cheap, safe, and eco-friendly near UV or even visible light emitting diodes (LEDs). To overcome this drawback, the covalent linkage of an iodonium salt to a chromophore absorbing at longer wavelength is actively researched. With aim at red-shifting the absorption spectrum of the iodonium salt, the synthesis of new compounds combining within a unique chemical structure both the chromophore (here the naphthalimide scaffold) and the iodonium salt is presented. By mean of this strategy, a polymerization could be initiated at 365 nm with the modified iodonium salts whereas no polymerization could be induced with the benchmark iodonium salt i.e., Speedcure 938 at this specific wavelength. To examine the effect of the counter-anion on the photoinitiating ability of these different salts, five different counter-anions were used. Comparison between the different anions revealed the bis(trifluoromethane)sulfonimide salt to exhibit the best photoinitiating ability in both the free radical polymerization of acrylates and the cationic polymerization of epoxides. To support the experimental results, molecular orbital calculations have been carried out. By theoretical calculations, the initiating species resulting from the photocleavage of the iodonium salts could be determined. The cleavage selectivity and the photochemical reactivity of the new iodoniums are also discussed.

  • Yang, X.; Giorgi, M.; Karoui, H.; Gigmes, D.; Hornebecq, V.; Ouari, O.; Kermagoret, A.; Bardelang, D. Chemical Communications 2019, 55 (92), 13824-13827.
    Résumé : Metal-organic framework (MOF) type crystals in which rigid, viologen-based pillars are surrounded by cucurbit[7]uril (CB[7]) macrocycles are described. These metal-organic rotaxane frameworks (MORF) are obtained by desolvation of a crystal precursor featuring a network already near-optimal toward 3D metal-ligand reticulation and show reversible photochromism.

  • Yin, H.; Cheng, Q.; Rosas, R.; Viel, S.; Monnier, V.; Charles, L.; Siri, D.; Gigmes, D.; Ouari, O.; Wang, R.; Kermagoret, A.; Bardelang, D. Chemistry-a European Journal 2019, 25 (54), 12552-12559.
    Résumé : The capture of pH-responsive guest molecules by CB[8] macrocycles made it possible to produce 2:2 host:guest complexes, releasing protons initially trapped on the guests, in a manner similar to the proton release observed in biology and operating through cascade supramolecular events. More information can be found in the Full Paper by R. Wang, A. Kermagoret, D. Bardelang, et al. (DOI: 10.1002/chem.201902057).

  • Zivic, N.; Kuroishi, P. K.; Dumur, F.; Gigmes, D.; Dove, A. P.; Sardon, H. Angewandte Chemie-International Edition 2019, 58 (31), 10410-10422.
    Résumé : Photopolymerization, or the use of light to trigger polymerization, is one of the most exciting technologies for advanced manufacturing of polymers. One of the key components in the photopolymerization processes is the photoactive compound that absorbs the light, generating the active species that promotes the polymerization and largely determines the final properties of the material. The field of photopolymerization has been dominated by photoradical generators to mediate radical reactions. In the last decade, to expand the number of polymers that can be prepared by photopolymerization, intensive research has been devoted to the synthesis and utilization of photoactive molecules that are able to generate a base or an acid upon irradiation. These organic compounds are known to promote not only the ring-opening polymerization of various heterocyclic monomers such as lactones, carbonates, or epoxides but also to trigger the step-growth synthesis of polyurethanes. This Minireview highlights the recent advances in the development of organic photobase and photoacid generators, with the aim of encouraging the wider application of these photoactive compounds in the photopolymerization area and to expand the use of these polymers in advanced manufacturing processes.
2018

  • Al Mousawi, A.; Arar, A.; Ibrahim-Ouali, M.; Duval, S.; Dumur, F.; Garra, P.; Toufaily, J.; Hamieh, T.; Graff, B.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Photochemical & Photobiological Sciences 2018, 17 (5), 578-585.
    Résumé : Six new carbazole based compounds (Ca1-Ca6) are synthesized and proposed as high performance photoinitiators with iodonium salt (iod) and/or an amine (EDB) for both the free radical polymerization (FRP) of acrylates and the cationic polymerization (CP) of epoxides upon near UV and visible light exposure using light emitting diodes (LEDs) @385 nm and @405 nm. Excellent polymerization initiating abilities are found and high final reactive function conversions are acquired. A full picture of the involved photochemical mechanisms is given.
    Mots-clés : photocatalysts, photopolymerization.

  • Al Mousawi, A.; Garra, P.; Sallenave, X.; Dumur, F.; Toufaily, J.; Hamieh, T.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Macromolecules 2018, 51 (5), 1811-1821.
    Résumé : Photopolymerization and 3D printing applications upon near-UV or visible light are currently limited to both rather low polymerization speed and thin layer by layer productions (below 100 mu m) using photoinitiating systems (PIS) mainly inherited from the 1990s. Filling the need for new PIS, two pi-conjugated dithienophosphole derivatives (DTPs) are synthesized and proposed as high performance near-UV and visible light photoinitiators/photoredox catalysts for both free radical polymerization (FRP) of (meth)acrylates and cationic polymerization (CP) of epoxides (e.g., using light-emitting diode (LED) at 405 nm). Astounding polymerization initiating abilities are found, and high final reactive function conversions are obtained (for multifunctional monomers). Their utilization as materials in laser write and 3D printing experiments is especially carried out with for the first time, about 2 mm 3D printed photopolymers in a one-layer approach. A full picture of the included photochemical mechanisms is additionally given. Originally, dithienophosphole derivatives are featured as metal-free photoinitiators/photoredox catalysts.
    Mots-clés : photoredox catalysts, photosensitizers, systems, transfer radical polymerization, visible-light.

  • Al Mousawi, A.; Schmitt, M.; Dumur, F.; Ouyang, J.; Favereau, L.; Dorcet, V.; Vanthuyne, N.; Garra, P.; Toufaily, J.; Hamieh, T.; Graff, B.; Fouassier, J. P.; Gigmes, D.; Crassous, J.; Lalevee, J. Macromolecules 2018, 51 (15), 5628-5637.
    Résumé : 3-Methyl-4-aza[6]helicene (A6H) enantiomers were synthesized and proposed as high-performance visible light photoinitiators and/or photosensitizers for the free radical polymerization (FRP) of (meth)acrylates upon visible light exposure using inexpensive and safe light-emitting diodes (LEDs) at 405 nm. Excellent polymerization initiating abilities were found, and high final conversions were obtained. Remarkably, an exceptional strongly enhanced chiral property of the polymer films was observed in the presence of the enantiopure azahelicenes. This is the first example of chiral properties introduced in polymer films by the photoinitiator through photopolymerization processes. It is of high interest as these latter are very fast and inexpensive polymerization techniques. Remarkably, contrary to chiral properties introduced by using a combination of commercial photoinitiator and chiral dopant, a dual behavior is found here for A6H. A full picture of the involved chemical mechanisms is given.
    Mots-clés : asymmetric catalysis, resolution.

  • Amaniampong, P. N.; Clement, J. - L.; Gigmes, D.; Ortiz Mellet, C.; Garcia Fernandez, J. M.; Bleriot, Y.; Chatel, G.; Vigier, K. D. O.; Jerome, F. Chemsuschem 2018, 11 (16), 2673-2676.
    Résumé : The irradiation of concentrated feeds of carbohydrates in alcoholic solution by high-frequency ultrasound (550kHz) induces the formation of alkylpolyglycosides (APGs). This work is distinct from previous reports in that it does not involve any (bio)catalyst or activating agent, it takes place at only 40 degrees C, thus avoiding degradation of carbohydrates, and it selectively yields APGs with a degree of polymerization in a window of 2-7, an important limitation of the popular Fischer glycosylation. This ultrasound-based technology proved successful with a range of different valuable carbohydrates and alkyl alcohols. The elucidation of the structure of all the produced glycosides strongly suggests that 1,6-anhydrosugars formed in situ are key intermediate species.
    Mots-clés : activation, alkylpolyglycosides, carbohydrates, cavitation, cellulose, glucose, glycosylation, kinetics, pyrolysis, sonoluminescence, surfactants, ultrasound, yield.

  • Autissier, L.; Mabrouk, K.; Chendo, C.; Guillaneuf, Y.; Rollet, M.; Charles, L.; Gigmes, D.; Trimaille, T. Chemistry-a European Journal 2018, 24 (15), 3699-3702.
    Résumé : A catalyst/initiator-free radical addition reaction performed under mild conditions (water, 30 degrees C) with high yields is reported for the first time. This reaction implies simple pH-mediated alkoxyamine dissociation followed by addition onto olefinic substrates. The versatility and relevance of this selective reaction for macromolecular conjugation and engineering are shown through the syntheses of block copolymers, as well as hydrogels containing insitu-loaded proteins, which could retain biological activity. This contrasts with standard thermal radical conditions that lead to complete protein inactivation.
    Mots-clés : access, alkoxyamines, block copolymers, click chemistry, copolymers, hydrogels, olefins, polymerization, powerful, radical addition, water solvent.

  • Banet, P.; Simonnet-Jegat, C.; Goubard, F.; Peralta, S.; Lalevee, J.; Gigmes, D.; Dumur, F. Materials Chemistry and Physics 2018, 211, 312-320.
    Résumé : A drop-casted thin film consisting of a Keggin-type polyoxometalate cluster K3PMo12O40 mixed with the semi-conducting poly(N-vinylcarbazole) (PVK) was deposited on top of ITO substrates. The resulting hybrid organic/inorganic film was characterized by electrochemistry, FT-IR spectroscopy, microscopies and spectroelectrochemistry. Interestingly, an electrochromic behavior could be evidenced from the resulting composite. (C) 2018 Elsevier B.V. All rights reserved.
    Mots-clés : acid, anions, electrochemical properties, Electrochromism, electrode, hybrid polyoxometalate, Multilayer, organic-inorganic materials, Polymer, Polyoxometalate, proton, pvk, sensor, state, water.

  • Baron, M.; Morris, J. C.; Telitel, S.; Clement, J. - L.; Lalevee, J.; Morlet-Savary, F.; Spangenberg, A.; Malval, J. - P.; Soppera, O.; Gigmes, D.; Guillaneuf, Y. Journal of the American Chemical Society 2018, 140 (9), 3339-3344.
    Résumé : The use of UV/visible light irradiation as a means to initiate organic syntheses is increasingly attractive due to the high spatial and temporal control conferred by photochemical processes. The aim of this work is thus to demonstrate that alkoxyamines bearing a chromophore on the alkyl moiety can provide a photoprotecting group for the sensitive nitroxide functionality, that is known to degrade through redox processes. The dissociation of various photosensitive alkoxyamines was studied from 223 to 298 K under UV/visible irradiation, depending on the nature of the chromophore. In each case a rapid (typically in less than 1 h) and near-quantitative dissociation was observed. As an illustration of the interest of this approach, a pyrene-based alkoxyamine was employed for the spatially controlled coupling of polymer chains onto Si wafers to produce micropatterned surfaces.
    Mots-clés : chemistry, cross-sections, functionalization, ligation, on bond homolysis, photo-generated thioaldehydes, photolabile protecting groups, polymers, science, surfaces.

  • Benkhaled, B. T.; Hadiouch, S.; Olleik, H.; Perrier, J.; Ysacco, C.; Guillaneuf, Y.; Gigmes, D.; Maresca, M.; Lefay, C. Polymer Chemistry 2018, 9 (22), 3127-3141.
    Résumé : Bacterial resistance to antibiotics is a major public health problem and there is an urgent need to find new antimicrobial materials to circumvent the development of resistant pathogens. The aim of this work is to propose an efficient and versatile method for the elaboration of antimicrobial polymeric materials based on the simple dispersion of a low amount of high molecular weight (M-n > 20 000 g mol(-1)) amphiphilic methacrylic copolymers prepared by nitroxide-mediated polymerization in different common organic matrices (here PS and PMMA). More precisely, after studying the influence of different copolymer parameters on their biological activity (the amount and type of comonomer (styrene or acrylonitrile), the architecture (random or diblock), and the type of cationic charge (permanent or not)), some selected candidates were dispersed in PS and PMMA matrices and were shown to efficiently turn these inactive materials into antibacterial ones without a significant hemolytic character. In particular, only 0.02 wt% of antimicrobial copolymers were sufficient to confer an activity against both Gram positive (B. subtilis) and Gram negative (E. coli) bacteria.
    Mots-clés : agents, antibacterial properties, block, fragmentation chain transfer, hemolytic activities, living radical polymerization, methyl-methacrylate, peptides, polymethacrylates, raft process.

  • Bonardi, A. H.; Dumur, F.; Grant, T. M.; Noirbent, G.; Gigmes, D.; Lessard, B. H.; Fouassier, J. - P.; Lalevee, J. Macromolecules 2018, 51 (4), 1314-1324.
    Résumé : Photopolymerization under near-infrared (NIR) light is challenging due to the low energy of the absorbed photon but, if successful, presents significant advantages. For example, this lower energy wavelength is safer than UV light that is currently the standard photocuring light source. Also, NIR allows for a deeper light penetration within the material and therefore resulting in a more complete curing of thicker materials containing fillers for access to composites. In this study, we report the use of three component systems for the NIR photopolymerization of methacrylates: (1) a dye used as a photosensitizer in the NIR range, (2) an iodonium salt as a photoinitiator for the free radical polymerization of the (meth)acrylates, and (3) a phosphine to prevent polymerization inhibition due to the oxygen and to regenerate the dye upon irradiation. Several NIR-absorbing dyes such as a cyanine borate and a silicon phthalocyanine are presented and studied. Systems using borate dyes resulted in methacrylate monomer conversion over 80% in air. We report three types of irradiation system: low-power LED at 660 and 780 nm as well as a higher power laser diode at 785 nm. The excellent performance reported in this work is due to the crucial role of the added phosphine.
    Mots-clés : color, dyes, organic photovoltaic devices, phthalocyanines, polymerization, silicon.

  • Bonardi, A. - H.; Bonardi, F.; Morlet-Savary, F.; Dietlin, C.; Noirbent, G.; Grant, T. M.; Fouassier, J. - P.; Dumur, F.; Lessard, B. H.; Gigmes, D.; Lalevee, J. Macromolecules 2018, 51 (21), 8808-8820.
    Résumé : The combination of thermally induced and photoinduced free radical polymerization of (meth)acrylic monomers has only been scarcely presented in the literature. In this study, a two-component system with a near- acts as a very efficient heat generator (heater) upon irradiation with NIR light. infrared (NIR) dye combined with a thermal initiator is presented. The dye Several thermal initiators are presented such as an alkoxyamine (e.g., BlocBuilder-MA), azo derivatives, and (hydro)peroxides. The heat delivered by the dye dissociates the thermal initiator, which initiates the free radical polymerization of (meth)acrylates. Several types of heat generators are presented such as borate-based dyes and a silicon phthalocyanine derivative. For the first time, the effects of the NIR heater concentration, light intensity, and monomer structure on the heat released are studied using thermal imaging studies. NIR light curing is challenging but offers significant advantages: it is safer than shorter wavelength, and it allows a deeper penetration of the light and therefore a better curing of filled samples for a unique access to composites. Systems using a cyanine borate as a dye give high conversion rate of C=C for methacrylate monomer under air. Two wavelengths of irradiation are studied: 785 and 850 nm. The presence of additives (phosphines or iodonium salts) can also improve the polymerization profiles.

  • Bonardi, A. - H.; Dumur, F.; Noirbent, G.; Lalevee, J.; Gigmes, D. Beilstein Journal of Organic Chemistry 2018, 14, 3025-3046.
    Résumé : Recent progresses achieved in terms of synthetic procedures allow now the access to polymers of well-defined composition, molecular weight and architecture. Thanks to these recent progresses in polymer engineering, the scope of applications of polymers is far wider than that of any other class of material, ranging from adhesives, coatings, packaging materials, inks, paints, optics, 3D printing, microelectronics or textiles. From a synthetic viewpoint, photoredox catalysis, originally developed for organic chemistry, has recently been applied to the polymer synthesis, constituting a major breakthrough in polymer chemistry. Thanks to the development of photoredox catalysts of polymerization, a drastic reduction of the amount of photoinitiators could be achieved, addressing the toxicity and the extractability issues; high performance initiating abilities are still obtained due to the catalytic approach which regenerates the catalyst. As it is a fast-growing field, this review will be mainly focused on an overview of the recent advances concerning the development of organic and organometallic photoredox catalysts for the photoreticulation of multifunctional monomers for a rapid and efficient access to 3D polymer networks.

  • Borie, C.; Mondal, S.; Arif, T.; Briand, M.; Lingua, H.; Dumur, F.; Gigmes, D.; Stocker, P.; Barbarat, B.; Robert, V.; Nicoletti, C.; Olive, D.; Maresca, M.; Nechab, M. European Journal of Medicinal Chemistry 2018, 148, 306-313.
    Résumé : A novel series of enediynes possessing pentafluorophenylsulfoxide have been developed. The innovative compounds possess antiproliferative activity against a broad panel of human cancer cells originating from breast, blood, lung, kidney, colon, prostate, pancreas or skin with IC50 ranging from 0.6 to 3.4 mu M. The antiproliferative activity of enediynes in darkness is associated to their ability to compromise microtubule network. In addition, exposure to UV leads to double-stranded DNA cleavage caused by the newly synthesized molecules reducing further their IC50 in nanomolar range against human tumor cells, including chemo-resistant pancreatic cancer cells. Taken together, the examined data demonstrate that enediynes possessing pentafluorosulfoxide are promising molecules in the cancer therapy. (C) 2018 Elsevier Masson SAS. All rights reserved.
    Mots-clés : Anticancer, bergman cyclization, cleavage, DNA cleavage, Enediynes, hypoxic tumors, in-vivo, Light activation, lysine, Microtubules, pancreatic-cancer, ph-gated transitions, photocleavage, selectivity, sulfones.

  • Bouzrati-Zerelli, M.; Guillaume, N.; Goubard, F.; Bui, T. - T.; Villotte, S.; Dietlin, C.; Morlet-Savary, F.; Gigmes, D.; Fouassier, J. P.; Dumur, F.; Lalevee, J. New Journal of Chemistry 2018, 42 (10), 8261-8270.
    Résumé : Photoinitiators exhibiting efficient thermally activated delayed fluorescence (TADF) are investigated. Known TADF metal complexes (copper-based structures) and purely organic molecules (carbazole/sulfone based organic structures) are used, for the first time, in the FRP of methacrylates, the CP of diepoxides and the synthesis of acrylate/diepoxide interpenetrated polymer networks, in thick films (1.4 mm), under air, under soft conditions using violet light delivered by a LED emitting at 405 nm. They are incorporated into two-component systems in combination with an iodonium salt and/or into three-component systems with iodonium salt/amine or N-vinylcarbazole or 9H-carbazole-9-ethanol (CARET) systems. A comparison with non-TADF analogues highlights the benefits of the TADF process. Using the copper complexes, the performances are better than those achieved with a conventional reference photoinitiator (bis acylphosphineoxide); the organic structures are noticeably less efficient. These systems exhibit a photoredox catalyst behavior. The involved chemical mechanism has been investigated using steady state photolysis, cyclic voltammetry, fluorescence spectroscopy, laser flash photolysis and electron spin resonance spin trapping techniques. The TADF property is found to be very important in increasing the excited state lifetime of the photoredox catalyst for better interactions with additives (i.e. a longer excited state lifetime is important to increase the yields of bimolecular reactions).
    Mots-clés : aldehydes, blue, cu(i) complexes, cu-i complexes, electroluminescence, emission, emitting electrochemical-cells, photoredox organocatalysis, polymerization, visible-light.

  • Bui, T. - T.; Goubard, F.; Ibrahim-Ouali, M.; Gigmes, D.; Dumur, F. Applied Sciences-Basel 2018, 8 (4), 494.
    Résumé : Organic light-emitting diodes offer attractive perspectives for the next generation display and lighting technologies. The potential is huge and the list of potential applications is almost endless. So far, blue emitters still suffer from noticeably inferior electroluminescence performances in terms of efficiency, lifespan, color quality, and charge injection/transport when compared to that of the other colors. Emitting materials matching the NTSC standard blue of coordinates (0.14, 0.08) are extremely rare and still constitutes the focus of numerous academic and industrial researches. In this context, we review herein the recent developments on highly emissive deep-blue thermally activated delayed fluorescence emitters that constitute the third-generation electroluminescent materials.
    Mots-clés : aggregation-induced emission, deep blue emitter, electroluminescent devices, electrophosphorescent devices, exciplex emission, highly efficient, iridium complexes, low roll-off, minor structural modifications, molecular design, oled, organic light emitting diode, tadf, thermally activated delayed fluorescence, tunable emission.

  • Bui, T. - T.; Goubard, F.; Ibrahim-Ouali, M.; Gigmes, D.; Dumur, F. Beilstein Journal of Organic Chemistry 2018, 14, 282-308.
    Résumé : The design of highly emissive and stable blue emitters for organic light emitting diodes (OLEDs) is still a challenge, justifying the intense research activity of the scientific community in this field. Recently, a great deal of interest has been devoted to the elaboration of emitters exhibiting a thermally activated delayed fluorescence (TADF). By a specific molecular design consisting into a minimal overlap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) due to a spatial separation of the electron-donating and the electron-releasing parts, luminescent materials exhibiting small S-1-T-1 energy splitting could be obtained, enabling to thermally upconvert the electrons from the triplet to the singlet excited states by reverse intersystem crossing (RISC). By harvesting both singlet and triplet excitons for light emission, OLEDs competing and sometimes overcoming the performance of phosphorescence-based OLEDs could be fabricated, justifying the interest for this new family of materials massively popularized by Chihaya Adachi since 2012. In this review, we proposed to focus on the recent advances in the molecular design of blue TADF emitters for OLEDs during the last few years.
    Mots-clés : blue, design strategy, electroluminescence, electroluminescent devices, emitter, high triplet energy, high-efficiency, host materials, oled, phosphine oxide, phosphorescent oleds, pure blue, quantum efficiency, substituted pyridine-derivatives, tadf.

  • Chendo, C.; Phan, T. N. T.; Rollet, M.; Gigmes, D.; Charles, L. Rapid Communications in Mass Spectrometry 2018, 32 (5), 423-430.
    Résumé : RationaleThe goal of this work was to modify the dissociation pathways of polylactide (PLA) holding benzyl and hydroxyl terminations, in order to circumvent coincidence of product ions generated during collisional activation of sodiated chains, which prevented their reliable characterization. MethodsBenzyl-, hydroxyl-terminated PLAs were ionized as ammonium adducts in positive ion mode electrospray and subjected to collision-induced dissociation (CID). Tandem mass spectrometry (MS/MS) experiments were conducted in a quadrupole time-of-flight (QTOF) instrument for safe assignment of product ions based on their elemental composition derived from accurate mass measurements. ResultsAdduction of ammonium to PLAs was found to induce chain fragmentation via charge-assisted processes, in great contrast to the charge-remote mechanisms experienced by sodiated molecules. The main reaction produced ions containing the termination only, hence allowing straightforward end-group determination. Other minor pathways were studied in detail to establish dissociation rules for ammoniated PLAs. Some reactions were found to be end-group specific, highlighting the higher reactivity of ammonium than alkali ion adducts. ConclusionsChanging the usually employed sodium-cationizing agent to ammonium was shown to induce dramatic changes in the CID behavior of PLAs. This was a simple and efficient approach to address issues encountered for end-group analysis of the particular PLA studied here.
    Mots-clés : electrospray-ionization, fragmentation pathways, liquid-chromatography, oligomers, polymer, tandem mass-spectrometry.

  • Cheng, Q.; Yin, H.; Rosas, R.; Gigmes, D.; Ouari, O.; Wang, R.; Kermagoret, A.; Bardelang, D. Chemical Communications 2018, 54 (98), 13825-13828.
    Résumé : A molecular switch built with cucurbit[7]uril and a 3-station viologen-phenylene-imidazole compound exhibited pH actuated ring translocation with high fatigue resistance (up to 10(2) cycles). The switch movement was harnessed toward selectively masking the toxicity of the viologen fragment at neutral pH near non-cancerous cells, while exposing it at acid pH near cancer cells.

  • Devaux, D.; Lienafa, L.; Beaudoin, E.; Maria, S.; Phan, T. N. T.; Gigmes, D.; Giroud, E.; Davidson, P.; Bouchet, R. Electrochimica Acta 2018, 269, 250-261.
    Résumé : A new family of single-ion-conductor block-copolymer electrolytes (BCEs), comprising poly(ethylene oxide) (PEO) as conducting block and poly(styrene sulfonyl(trifluoromethanesulfonyl) imide of lithium) (PSTFSI) as structural block, was developed recently. To evaluate the influence of the structural blockon the physico-chemical and electrochemical properties, we compare two single-ion-conductor BCE families with structural blocks made of either PSTFSI or poly(3-sulfonyl(trifluoromethanesulfonyl) imide propyl methacrylate of lithium) (PMATFSI). Small-angle X-ray scattering revealed that at temperatures lower than the PEO block melting temperature, the morphology of both families is lamellar whereas, at higher temperatures, the electrolytes are in a disordered state. Both electrolyte families present an ionic conductivity maximum for some weight fraction of the structural block (w(BTFSI)), named BTFSI. For w(BTFSI) > 0.17, the ionic conductivity of the PMATFSI-based electrolytes is larger than that of the PSTFSI-based electrolytes by at least a factor of two. Based on a detailed transport analysis, we show that the strong increase of the glass transition temperature is the main factor limiting the ionic conductivity. We also interpret the conductivity maximum of the PSTFSI-based electrolytes by a limitation in available free charges for w(PSTFSI) > 0.17 while the polymer dynamics slows down. The optimization of the ionic transport in this type of single-ion-conductor BCE requires promoting the compatibility of the Lithornbearing structural block with the conducting block. (C) 2018 Elsevier Ltd. All rights reserved.
    Mots-clés : behavior, delocalized polyanion, Lithium battery, lithium-metal batteries, molecular-weight, peo, poly(ethylene oxide), Polymer electrolyte, polymer electrolytes, Single-ion conductor, solid-state, temperature, transport, triblock copolymers, vtf.

  • Dumur, F.; Ibrahim-Ouali, M.; Gigmes, D. Applied Sciences-Basel 2018, 8 (4), 539.
    Résumé : In this study, a phthalimide-based fluorescent material has been examined as a green emitter for multilayered organic light-emitting diodes (OLEDs). By optimizing the device stacking, a maximum brightness of 28,450 cd/m(2) at 11.0 V and a maximum external quantum efficiency of 3.11% could be obtained. Interestingly, OLEDs fabricated with Fluo-2 presented a 20-fold current efficiency improvement compared to the previous results reported in the literature, evidencing the crucial role of the device stacking in the electroluminescence (EL) performance of a selected emitter. Device lifetime was also examined and an operational stability comparable to that reported for a standard triplet emitter i.e., bis(4-methyl-2,5-diphenyl-pyridine) iridium(III) acetylacetonate [(mdppy)(2)Iracac] was evidenced.
    Mots-clés : acceptors, device architecture, devices, fluorescence, fluorescent, green, host, oled, phosphorescence, phosphorescent emitter, recent progress, solar-cells.

  • Garra, P.; Morlet-Savary, F.; Graff, B.; Dumur, F.; Monnier, V.; Dietlin, C.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Polymer Chemistry 2018, 9 (12), 1371-1378.
    Résumé : Metal Acetylacetonate-Bidentate Ligand Interaction (MABLI) is presented here as a new chemical mechanism for the highly efficient generation of free radicals for polymer synthesis. This MABLI process involves simultaneous ligand exchange and a change of the metal oxidation degree and is associated with the efficient release of free radicals. In conventional redox two-component radical generating systems, two criteria are required to be efficient: (1) oxidizing agents must exhibit a low bond dissociation energy (BDE) i.e. they are usually unstable (e.g. peroxides) and (2) a small difference must exist between the oxidation potential of the reducing agent and the reduction potential of the oxidation agent. In contrast, here, the criteria for efficient MABLI radical generation were energetic and geometric for both bidentate ligands and metal acetylacetonates. The strength of this approach is to use stable compounds in 2-components free radical initiating systems and to generate carbon centered radicals. Mechanistic investigations demonstrated the formation of new metal adducts by means of high-resolution mass spectroscopy (HR-ESI-MS) as well as UV-vis spectrometry. As a result of its high radical generating rate, the potential of MABLI was illustrated on the methacrylate free radical polymerization under mild conditions (room temperature, in air) and initiated with a small amount of metal acetylacetonate though it opens new perspectives for acac-like additions in organic chemistry.
    Mots-clés : catalysis, complexes, initiating systems, methacrylate, oxygen inhibition, reactivity, redox polymerization, resonance, spectroscopy, standard enthalpies.

  • Garra, P.; Carre, M.; Dumur, F.; Morlet-Savary, F.; Dietlin, C.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Macromolecules 2018, 51 (3), 679-688.
    Résumé : Simultaneous redox free radical polymerization (FRP) and redox cationic polymerization (CP) are combined for the synthesis of methacrylate/diepoxide interpenetrating polymer networks (IPN). At first, the Cu(acac)(2)/phosphine/iodonium salt operates according to the principles of free radical promoted cationic polymerization (FRPCP). A photoactivation of the reaction for that system was necessary to enhance the mild methacrylate and diepoxide conversions. Second and at least, two complementary copper catalytic cycles are used simultaneously: the recently developed Cu(II)/reducing agent/peroxide FRP system combined with the older Cu(II)/reducing agent/iodonium salt redox CP system. For this latter hybrid system, outstanding efficiency was observed with more than 90% of epoxy functions conversion for the cationic difunctional monomers and 78% conversion for the vinylic functions conversion for difunctional monomers. The radical and cation generations are discussed in order to fill the interrogations raised by the experimental results. The relevance of dual FRP/CP in IPN synthesis is fully demonstrated. The performance of the hybrid copper catalytic system is remarkable to overcome the oxygen inhibition; i.e., almost no oxygen inhibited layers are observed compared to the >60 mu m inhibited layer obtained with a reference redox FRP such as amine/BPO.
    Mots-clés : 3d printing resins, cationic-polymerization, confocal raman microscopy, dental resins, free-radical polymerization, in-situ formation, peroxide, photoinitiating systems, photopolymerization, redox polymerization.

  • Garra, P.; Dumur, F.; Gigmes, D.; Nechab, M.; Morlet-Savary, F.; Dietlin, C.; Gree, S.; Fouassier, J. P.; Lalevee, J. Macromolecules 2018, 51 (7), 2706-2715.
    Résumé : Free radical polymerization (FRP) initiation from metal acetylacetonate-bidentate ligand interaction (MABLI) under mild conditions (room temperature, under air) is discussed here for different metal centers (Mn, V, and Cu). First, without light, in MABLI systems such as V(acac)(3)/2-diphenylphosphinobenzoic acid (2dppba), Mn(acac)(3)/2dppba, or Cu(acac)(2)/2dppba, electron-rich aryl (Ar-center dot) radicals were conveniently and efficiently produced by the reaction of electron-poor acac(center dot) radicals with the iodonium salt (Iod), leading to an enhancement of pure redox (no light) polymerizations. Second, it was found that V(III)*/Iod reaction is generating aryl (Ar-center dot) radicals at a high enough rate to initiate a photopolymerization process upon mild irradiation (LED@405 nm). This reaction can be implemented in redox photoactivated systems (e.g., using three-component V(acac)(3)/2dppba/Iod systems) in order to spectacularly enhance a slow redox process from 40 degrees C exothermicity in 800 s to 93 degrees C in less than 200 s. Third, an impressive chemical bleaching (without light) was reported for the Mn(acac)(3)/2dppba reaction. Photoactivation of the Mn(acac)(3)/2dppba/Iod system led to outstanding FRP initiation efficiencies (<20 s for more than 85% C=C conversion of a low-viscosity methacrylate resin). Light enhancement of surface curing was confirmed for all the redox photoactivated polymerizations using Raman confocal microscopy. Overall, amine-free peroxide-free MABLI radical initiating systems were highly improved for safer and even more efficient redox (photoactivated) polymerizations. This original combination of redox polymerization and photopolymerization will be highly worthwhile to combine in one approach the advantages of both techniques.
    Mots-clés : 3d printing resins, cationic-polymerization, confocal raman microscopy, dental resins, initiating systems, oxygen inhibition, photoinitiating systems, photopolymerization processes, reactivity, shadow areas.

  • Garra, P.; Dumur, F.; Mokbel, H.; Monnier, V.; Morlet-Savary, F.; Dietlin, C.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Acs Omega 2018, 3 (9), 10938-10944.
    Résumé : Photoredox catalysis based on the [Cu(neo)(DPEphos)]BF4 copper complex allowed getting a significant improvement of the polymerization performances (e.g., thick samples, coatings ...) compared to that obtained with other benchmarked photoinitiators in both cationic (CP) and free radical polymerizations (FRP). Nevertheless, as for other copper complexes classically used as photoinitiators in polymer science, the synthesis of these complexes is carried out in a solvent; this fact remains an obstacle to their widespread use because of the cost associated with the use of a solvent and the complex synthesis procedure. In the present study, on the contrary, an outstanding efficient mechanosynthesis of [Cu(neo)(DPEphos)]BF4-purity >= 95% outranking the previous Cu(I) mechanosynthesis. allowed (i) to divide the synthesis time by 170-fold (as only 5 min is necessary to get the complex), (ii) to lower the environmental impact and cut the synthetic costs associated with solvent usage, and (iii) to access a new Cu(I) complex with a counteranion that is impossible to introduce under the traditional chemistry methods (e.g., I-). Reactivities of the mechanosynthesized copper complexes in resins (FRP and CP) confirmed the very high purity of the obtained copper complex by H-1 nuclear magnetic resonance spectroscopy and high-resolution electrospray ionization mass spectrometry.
    Mots-clés : copper(i) complexes, initiating systems, mechanochemical synthesis, methyl-methacrylate, oxygen inhibition, photocatalysis, photoinitiating systems, photopolymerization, polymerization, strategies.

  • Garra, P.; Dumur, F.; Nechab, M.; Morlet-Savary, F.; Dietlin, C.; Graff, B.; Doronina, E. P.; Sidorkin, V. F.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Macromolecules 2018, 51 (16), 6395-6404.
    Résumé : New peroxide-free, amine-free, and phosphine-free redox free radical polymerization (RFRP) initiating systems comprising remarkably stable (i) metal acetylacetonates (Mn(acac)(3), Cu(acac)(2)) and (ii) carbonyl compounds bearing labile hydrogen in the alpha-position are presented for polymerization initiation under mild conditions (under air, at room temperature, nonpurified monomers). The systems proposed in this work are competitive or even outranked the well-known peroxide-based RFRP reference in several criteria: (i) toxicity, (ii) stability, (iii) surface curing, (iv) overall double-bond conversions, and (v) workability of the RFRP mixture (longer gel times are now possible). Radical initiating reactions are studied using many complementary experimental/theoretical techniques: optical pyrometry, thermal imaging, Raman confocal microscopy, electron spin resonance (ESR), ESR spin trapping (ESR-ST), high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), density functional theory (DFT), simulations of bond dissociation energies (BDE), reaction enthalpies, and DFT simulations of seven unknown ESR-ST adducts. A full consistent picture of the chemical mechanisms involved in these new redox systems is provided.
    Mots-clés : alkyd paints, confocal raman microscopy, dental resins, initiating systems, ligand interaction mabli, manganese tris(acetylacetonate)-acetic acid, monitoring photopolymerization reactions, organic halides, shadow areas, translucent fiberglass post.

  • Garra, P.; Dumur, F.; Nechab, M.; Morlet-Savary, F.; Dietlin, C.; Graff, B.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Polymer Chemistry 2018, 9 (16), 2173-2182.
    Résumé : The use of new stable copper acetylacetonates in combination with specific bidentate ligands (e.g. 2dppba) is proposed for redox free radical polymerization (FRP) under mild reaction conditions (under air and at room temperature). These systems show high performances so that they can compete with the well-established reference redox initiating systems based on the amine/benzoylperoxide combination. Remarkably, some of our systems are also highly efficient when excited in the near infrared region (NIR), demonstrating that our redox systems can also be activated by light. Using this strategy, the initial redox free radical polymerization could be converted into a redox photoactivated one. More interestingly, a stable copper methacryloyloxy-ethylacetoacetate (Cu(AAEMA)(2)) bearing a reactive methacrylate function and a copper acetylacetonate moiety could be used to polymerize a first polymer layer onto which a second polymerization could be carried out. Precisely, the second polymerization was initiated by a redox process using mild reaction conditions (at room temperature and under air), different from the process used to form the underlayer. To the best of our knowledge, this re-initiation of polymerization from a pre-polymerized layer by a second polymerization technique is highly original and is of crucial industrial/academic interest as no high energy consumption/harmful wavelengths are required to reinitiate the polymerization. The efficiency of this strategy is illustrated by grafting from a 3D printed object.
    Mots-clés : chemistry, complex, composites, confocal raman microscopy, initiating systems, photoinitiating systems, photopolymerization processes, polymers, resins, shadow areas.

  • Gaston, F.; Dupuy, N.; Marque, S. R. A.; Gigmes, D.; Dorey, S. Journal of Applied Polymer Science 2018, 135 (18), 46114.
    Résumé : gamma-Irradiated films could provoke unexpected interaction with proteins for instance just after irradiation and not necessarily after 12 months indicating there is no more reactive species. The optical properties of two multilayer films [polyethylene (PE)/ethylene vinyl alcohol (EVOH)/PE and ethylene vinyl acetate (EVA)/EVOH/EVA] after different -irradiation doses is then studied in this work. The investigation on these films, either non-irradiated or -irradiated (up to 270 kGy), is performed by colorimetry measurement over time (up to 12 months) to assess the generation of new species inside the materials. The color change is directly correlated with absorbed -doses. Over time, the color decreases and goes back to its initial time level. This discoloration evolution could be therefore used as an indication of the completion of the generated species reactions induced by -irradiation. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46114.
    Mots-clés : biomedical applications, commercial monolayer, degradation, food-packaging materials, gamma-radiation, grade pvc, ionizing-radiation, mechanical-properties, multilayer films, olive oil, phenolic antioxidants, pvdc/pvc films, spectroscopy.

  • Gigmes, D.; Van Steenberge, P. H. M.; Siri, D.; D'hooge, D. R.; Guillaneuf, Y.; Lefay, C. Macromolecular Rapid Communications 2018, 39 (19), 1800193.
    Résumé : The radical copolymerization of vinyl and cyclic ketene acetal (CKA) monomers is a promising way to prepare degradable vinyl polymers. The reactivity of the comonomer pair is known to be dependent of the vinyl monomer structure that requires to play with experimental conditions (feed ratio, overall monomer conversion, etc.) to target a desired cumulative (average) copolymer composition. Even if the materials are completely degradable, there is no information about the homogeneity of the degraded products. This theoretical study, using kinetic Monte Carlo simulations, allows simulating degradation at the molecular level. It is shown that disparate reactivity ratios (styrene/CKA, etc.) and also a composition drift at high conversion can lead to an inhomogeneous degraded product compared to systems with similar reactivity ratios (vinyl ether/CKA, etc.). The use of reversible deactivation radical polymerization techniques does not influence the final degraded products and is only useful for the design of advanced macromolecular architectures before degradation.
    Mots-clés : 2-methylene-1,3-dioxepane, biomedical applications, caprolactone, chemistry, cyclic ketene acetal, degradable polymers, kinetic Monte Carlo simulation, limitations, model-based design, polyesters, polymers, radical ring-opening polymerization, reactivity ratio, ring-opening polymerization.

  • Ho, H. T.; Rollet, M.; Phan, T. N. T.; Gigmes, D. European Polymer Journal 2018, 107, 74-81.
    Résumé : Sulfonyl(trifluoromethylsulfonyl) imide anion (STFSI, -SO2N(-)SO2CF3) is one of the most important sulfonimide groups for organic and material synthesis. However, the synthesis of STFSI-functionalized monomers and related polymers is still a problematic issue, comprising multi-step and complex synthetic processes. To overcome this drawback, we developed a robust and versatile strategy to prepare original STFSI-based monomers using the "Michael addition" reaction conducted in the presence of vinyl sulfonyl(trifluoromethylsulfonyl)imide and either an amine or a malonate derivative. Furthermore, the synthesized monomers were used to prepare the corresponding STFSI-functionalized polymers using step-growth polymerization with potential applications as electrolytes.

  • Kalashnyk, N.; Dumur, F.; Gigmes, D.; Clair, S. Chemical Communications 2018, 54 (61), 8510-8513.
    Résumé : The supramolecular self-assembly of s-indacene-1,3,5,7(2H,6H)-tetrone (INDO4) on Ag(111), Ag(100) and Ag(110) surfaces was studied using scanning tunneling microscopy (STM). Four similar brickwall-type phases were found and in two of them the molecules appeared with distinct alternating contrast. The origin of this effect is discussed in terms of molecular adaptation.
    Mots-clés : acid, adsorption, ag(111), architectures, interface, monolayers, orientation, scanning-tunneling-microscopy, spectroscopy, substrate.

  • Kalashnyk, N.; Salomon, E.; Mun, S. H.; Jung, J.; Giovanelli, L.; Angot, T.; Dumur, F.; Gigmes, D.; Clair, S. Chemphyschem 2018, 19 (15), 1802-1808.
    Résumé : Original reaction pathways can be explored in the on-surface synthesis approach where small aromatic precursors are confined to the surface of single crystal metals. The bis-indanedione molecule reacted with itself on silver surfaces in different ways, through a Knoevenagel reaction or an oxidative coupling, leading to the formation of a variety of new molecular compounds and covalently-linked 1D or 2D networks. Noteworthy, original reaction products were obtained that cannot be synthesized in traditional solvent-based chemistry. The lowest activation temperature for the homo-coupling reactions was found on the Ag(111) surface. The Ag(110) was highly selective in terms of coupling reaction type, while on Ag(100) the temperature could finely control the selectivity. The on-surface synthesis approach is shown here to be particularly efficient to produce original compounds in mild conditions, using activation temperatures as low as 200 degrees C. The different structures were characterized by scanning tunnelling microscopy (STM) together with X-ray photoelectron emission spectroscopy (XPS) and high-resolution electron energy loss spectroscopy (HREELS).
    Mots-clés : 1,3-indandione, acid, ag(111), bond, dependent catalytic-activity, derivatives, heterogeneous catalysis, on-surface synthesis, oxidation, regioselectivity, scanning probe microscopy, scanning-tunneling-microscopy, self-assembly strategy, supramolecular chemistry.

  • Lepeltier, M.; Sallenave, X.; Tondelier, D.; Sini, G.; Goubard, F.; Gigmes, D.; Geffroy, B.; Dumur, F. Synthetic Metals 2018, 240, 21-29.
    Résumé : In this study, three donor-acceptor-donor triphenylamine/oxadiazole hybrids differing by the substitution pattern were synthesized and characterized by means of experimental and density functional theory (DFT) methods. The new compounds were used as hosts for the design of yellow- and green organic light emitting diodes (OLEDs), exhibiting very different EL characteristics. The position of the triphenylamine substituents relative to the central phenyl-oxadiazole-phenyl core was found to greatly influence the EL performances. The results indicate that the increased internal torsion and the disrupture of the interring pi-conjugation of the hosts impacts importantly the triplet energies andthe EL performance of OLEDs. OLEDs fabricated with the best host afforded an external quantum efficiency (EQE) of 17.1%, a current and power efficiency of 59.3 cd/A and 29.5 lm/W while doping the emissive layer at 10 wt% with the triplet emitter Ir(ppy)(3).
    Mots-clés : blue organic electrophosphorescence, charge balance, devices, efficiency, Electroluminescence, emission, energy, fluorescence, host materials, Iridium complex, iridium complexes, oled, Phosphorescence, reliable prediction, Triplet state, Yellow emission.

  • Lienafa, L.; Monge, S.; Guillaneuf, Y.; Ameduri, B.; Siri, D.; Gigmes, D.; Robin, J. - J. European Polymer Journal 2018, 109, 55-63.
    Résumé : A novel route to prepare fluorinated grafted copolymers via the use of nitroxides and under mild conditions is described. First, iodine transfer polymerization of vinylidene fluoride (VDF) in the presence of 1-iodoper-fluorohexane led to two PVDFs (average molar masses of 1700 and 4000 g mol(-1) and dispersities of 1.2). Then, the grafting of nitroxide moieties onto PVDF backbone was achieved in solution without any polymer activation. The obtained PVDF-g-nitroxide polymers acted as efficient macroinitiators for the polymerization of styrene leading to PVDF-g-PS graft copolymers with styrene content ranging from 17 to 40 w.% and PS molar masses varying from 1000 to 1500 g mol(-1). It was experimentally evidenced that the grafting took place from methylenic protons, especially from tail-to-tail addition, and theoretical calculations of bond dissociation energies confirmed such a finding. It was also demonstrated that the nature of the solvent had a great influence on the success of the grafting mechanism as the reaction was only efficient in N-methyl pyrrolidone. Considering the high chemical stability of PVDF, this chemical route paves the way towards the synthesis of various valuable graft copolymers.

  • Ouertani, A.; Chaabouni, I.; Mosbah, A.; Long, J.; Barakat, M.; Mansuelle, P.; Mghirbi, O.; Najjari, A.; Ouzari, H. - I.; Masmoudi, A. S.; Maresca, M.; Ortet, P.; Gigmes, D.; Mabrouk, K.; Cherif, A. Frontiers in Microbiology 2018, 9, 1148.
    Résumé : Milk and dairy products harbor a wide variety of bacterial species that compete for both limited resources and space. Under these competitive conditions, bacteria develop specialized mechanisms to protect themselves during niche colonization and nutrient acquisition processes. The bacterial antagonism mechanisms include the production of antimicrobial agents or molecules that facilitate competitor dispersal. In the present work, a bacterial strain designated RC6 was isolated from Ricotta and identified as Bacillus cereus. It generates antimicrobial peptide (AMP) when grown in the presence of casein. The AMP was active against several species of Bacillus and Listeria monocytogenes. MALDI-TOF analysis of the RP-HPLC purified fractions and amino acid sequencing revealed a molecular mass of 751 Da comprised of a 6-residue sequence, YPVEPF. BLAST analysis showed that the AMP corresponds to the fractions 114-119 of bovine pl-casein and represents the product of a specific proteolysis. Analysis of the purified proteolytic fractions from the B. cereus RC6 culture supernatant indicated that the presence of at least two different endoproteases is crucial for the generation of the AMP. Indeed, we were able to identify two new candidate endoproteases by means of genome sequencing and functional assignment using a 3D structural model and molecular docking of misannotated hypothetical proteins. In this light, the capacity of B. cereus RC6 to generate antimicrobial peptides from casein, through the production of extracellular enzymes, presents a new model of antagonistic competition leading to niche colonization. Hence, as a dairy product contaminant, this strategy may enable proteolytic B. cereus RC6 niche specialization in milk matrices.
    Mots-clés : 3D structure prediction, alignment, antibacterial, antimicrobial peptide, B. cereus, beta-casein, bioactive peptides, dairy-products, endoproteases, enzyme, genome sequencing, molecular docking, protein, quality, raw-milk, strains, thuringiensis.

  • Palud, D.; Soioulata, A.; Haw, C.; Mugnier, L.; Jarrosson, F.; Tarbe, M.; Mollet, C.; de Pomyers, H.; Gigmes, D.; Mabrouk, K. Toxicon 2018, 149, 94-95.
    Mots-clés : esi-ms, Fasciculin II, Folding, fplc, hplc, Peptide synthesis, Venom.

  • Pertici, V.; Martrou, G.; Gigmes, D.; Trimaille, T. Current Medicinal Chemistry 2018, 25 (20), 2385-2400.
    Résumé : Background: Over the last decades, synthetic polymer-based electrospun nano/microfibers have emerged as potent materials in crucial biomedical applications such as tissue engineering, drug delivery and diagnostics. This is mainly attributed to versatility and reproducibility of the electrospinning (ES) process, as well as the high surface- to-volume ratio of the generated nanostructures. Appropriate functionalization with dedicated biomolecules (i.e. cell adhesive peptides, therapeutic molecules, bio-probes) is a critical requirement for the performances of such materials in their related application. Methods: We report on the different chemical methodologies for preparing biofunctionalized synthetic polymer fibers, on the basis of two main approaches: biomolecule introduction after ES process (post-ES) and before ES (pre-ES). We then focused on the latest implications of such materials in areas of tissue engineering, drug delivery and diagnostics. Results: This review describes the numerous immobilization strategies (either covalent or non-covalent) developed for designing biofunctionalized fibers, as well as their impact on their properties in dedicated application. The inputs of advanced conjugation tools ("clickable" chemistries, PEG linkers) for biofunctionalization are also highlighted. In the light of the literature, it appears that increasing research efforts are now devoted to multifunctional character and fiber combination with other materials (hydrogels, inorganic particles, microfluidic devices) for improved and tunable performances. Conclusion: Owing to flexibility and robustness of ES process as well as advances in conjugation and polymer/material engineering, high degree of control over biofunctionalization can now be achieved, to fit as best as possible the requirements of the targeted application. The performances reached up to now augur well for the future of such class of materials.
    Mots-clés : biofunctionalization, biomedical applications, block-copolymers, cell adhesion, click chemistry, conjugation chemistry, diagnostics, drug delivery, electrospinning, fibrous scaffolds, nanofibrous scaffolds, protein immobilization, rgd-peptide, surface modification, Synthetic polymers, tissue engineering, vascular graft.

  • Verdoni, M.; De Pomyers, H.; Gigmes, D.; Luis, J.; Migan, N.; Badirou, E. M.; Amoussouga, S.; Bengeloune, A. H.; Mabrouk, K. Toxicologie Analytique Et Clinique 2018, 30 (1), 61-68.
    Résumé : Our study aims to show the illicit use of certain ingredients in the composition of cosmetic depigmenting products. For this purpose, a method of identification and quantification using High Performance Liquid Chromatography coupled to mass spectrometry (CLHP/SM) has been developed, allowing the characterization and rapid determination of various regulated and/or prohibited molecules. Two molecules have been studied: hydroquinone and kojic acid, which are the most regulated substances used. These molecules used commonly in "whitening" cosmetic products with a high incorporation percentage generating important side effects. This improper use is now at the origin of a real public health concern called voluntary depigmentation. Our results show that the International Nomenclature of Cosmetic Ingredients (INCI) composition of some cosmetics, as given by the manufacturers, can be misleading. Indeed, (i) hydroquinone presence is clearly alleged in three tested products when hydroquinone was found in five products, (ii) five of seven tested products contain hydroquinone in higher percentage than mentioned, (iii) similarly three cosmetics contain both hydroquinone and kojic acid whereas the latter was stated in the composition of only two of them. Thus, the development of this new technique enables the verification of the compositions claimed by manufacturers and can contribute to protecting the consumers' health of cosmetic products. (C) 2017 Societe Francaise de Toxicologie Analytique. Published by Elsevier Masson SAS. All rights reserved.
    Mots-clés : Bleaching cosmetics products, corticosteroids, HPLC-MS method, Hydroquinone, Kojic acid.

  • Yin, H.; Rosas, R.; Gigmes, D.; Ouar, O.; Wang, R.; Kermagoret, A.; Bardelang, D. Organic Letters 2018, 20 (11), 3187-3191.
    Résumé : Among a series of metal ions in water, silver is the only one to remotely and reversibly switch cucurbit[7]uril (CB[7]) movements (translocation or uptake) on a rigid and linear three station viologen phenylene imidazole (V-P-I) derivative, avoiding undesired pH actuation. H-1 NMR, UV-vis spectroscopy, mass spectrometry, ITC, and modeling were combined to show that ring translocation or uptake along a molecular thread is possible in water by Ag+ as a metal stimulus.
    Mots-clés : artificial molecular machines, benzimidazolium, binding, cations, chemistry, coordination, cucurbituril, recognition sites, shuttle, synthetic receptor.

  • Zhang, J.; Zivic, N.; Dumur, F.; Xiao, P.; Graff, B.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Chemphotochem 2018, 2 (6), 481-489.
    Résumé : The photochemical mechanism of the radical generation from photoinitiating systems based on 1, 8-naphthalimide derivatives (ANDs; with tertiary amine moieties) are investigated by using various approaches including cyclic voltammetry, steady-state photolysis, and electron spin resonance spin-trapping techniques. It reveals that radicals can be produced from ANDs alone or ANDs/additive (e.g. iodonium salt or chloro triazine) combinations. The generated radicals and cations can initiate both free-radical and cationic photopolymerization reactions under irradiation with various light-emitting diodes or a halogen lamp. For most of the AND-based photoinitiating systems, more than 60% of acrylate or epoxide conversions were attained, and were even higher than those obtained by using commercial photoinitiators, for example, bisacylphosphine oxide or camphorquinone. More interestingly, the AND1-based photoinitiating system can also initiate concomitant cationic/radical polymerizations and can be used for the synthesis of interpenetrated polymer networks.
    Mots-clés : cationic photopolymerization, cationic-polymerization, curcumin, interpenetrated polymer networks, kinetics, laser flash-photolysis, light-emitting diodes, naphthalimide derivatives, photochemistry, photoinitiators, photophysical properties, photopolymerization, polymerization reactions, radical photopolymerization, versatile photoinitiators, visible lights.

  • Zhang, J.; Zivic, N.; Dumur, F.; Xiao, P.; Graff, B.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Polymer Chemistry 2018, 9 (8), 994-1003.
    Résumé : Four N-[2-(dimethylamino) ethyl]-1,8-naphthalimide derivatives (ANNs) with different substituents (bromo group, primary amine, secondary amine, and tertiary amine) in the naphthalimide skeleton have been synthesized and can be used as one-component free radical photoinitiators or incorporated into multicomponent photoinitiating systems for free radical or cationic photopolymerization under the irradiation of various LEDs. ANN2 (with secondary amine substituent) or ANN3 (with tertiary amine substituent) alone is capable of initiating the free radical polymerization of acrylates under a LED at 405 nm while ANN0 (with bromo substituent) or ANN1 (with primary amine substituent) does not work. When combined with various additives (e.g. iodonium salt, N-vinylcarbazole, chloro triazine, or tertiary amine), most of the ANN1-3 based multi-component photoinitiating systems are efficient in free radical photopolymerization at 385 nm, 405 nm, 455 nm, 470 nm and even under a low-intensity polychromatic visible light (from a halogen lamp) with the final conversions being higher than 60% (even more efficient than commercial photoinitiators bisacylphosphine oxide and camphorquinone). In addition, ANN1-3 based photoinitiating systems also exhibit a high efficiency for cationic photopolymerization of epoxides upon diverse LEDs. The ANN2 based photoinitiating system can also be used for the synthesis of interpenetrated polymer networks and adapted for 3D printing. The photochemical mechanisms of the ANN based systems have been comprehensively investigated and discussed in detail.
    Mots-clés : anhydride derivatives, cationic-polymerization, challenges, kinetics, mechanism, naphthalimide, opportunities, photopolymerization, systems, visible-light.
2017

  • Al Mousawi, A.; Dumur, F.; Garra, P.; Toufaily, J.; Hamieh, T.; Goubard, F.; Bui, T. - T.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2017, 55 (7), 1189–1199.
    Résumé : In this article, novel azahelicenes (AZs) were synthesized and proposed as high performance visible light photoinitiators for both the free radical polymerization of acrylates and the cationic polymerization (CP) of epoxides upon visible light exposure using Light Emitting Diodes (LEDs) @405, @455, and @470 nm. Excellent polymerization initiating abilities are found and high final conversions were obtained. Remarkably, an exceptional long lifetime photoluminescence property of the polymer films was observed when synthesized in presence of AZs. A full picture of the involved chemical mechanisms is given. AZs being high performance photoinitiators, their use in new cationic LED 3D printing resins will be also presented, that is, the cationic process upon LED projector @405 nm can be useful to reduce the shrinkage usually observed for radical polymerization. LED projector printing is very interesting compared to laser writing as this technology projects the profile of an entire layer of a 3D object at one time. (c) 2016 Wiley Periodicals, Inc.
    Mots-clés : cationic polymerization, electron, Free radical polymerization, helicenes, initiators, light-emitting diodes, Photochemistry, Photoinitiators, photopolymerization, sensor, water.

  • Al Mousawi, A.; Dumur, F.; Garra, P.; Toufaily, J.; Hamieh, T.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Macromolecules 2017, 50 (7), 2747–2758.
    Résumé : Four new carbazole derivatives (C1-C4) are synthesized and proposed as high performance visible light photoinitiators/photoredox catalysts for both the free radical polymerization (FRP) of (meth)acrylates and the cationic polymerization (CP) of epoxides upon visible light exposure using light-emitting diodes (LEDs) at 405, 455, and 477 nm. Excellent polymerization initiating abilities are found, and high final reactive function conversions are obtained. Interestingly, these new derivatives exhibit much better visible light polymerization initiating ability compared to a reference UV-absorbing carbazole (CARET, 9H-carbazole-9-ethanol) showing that the new substituents are of great interest to red-shift the absorption of the proposed photoinitiators. More remarkably, in combination with an iodonium salt, C1-C4 are also better than the well-known bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO) photoinitiator for mild irradiation conditions highlighting their outstanding reactivity. Their use in new cationic resins for LED projector 3D printing is particularly outlined. A full picture of the involved photochemical mechanisms is provided. Originally, these carbazoles behave as metal-free photoredox catalysts active in both oxidative and reductive cycles.
    Mots-clés : atom-transfer, cationic-polymerization, n-vinylcarbazole, Photocatalysts, photopolymerization, transfer radical polymerization, visible-light.

  • Al Mousawi, A.; Garra, P.; Dumur, F.; Bui, T. - T.; Goubard, F.; Toufaily, J.; Hamieh, T.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Molecules 2017, 22 (12), 2143.
    Résumé : Radical chemistry is a very convenient way to produce polymer materials. Here, an application of a particular photoinduced radical chemistry is illustrated. Seven new carbazole derivatives Cd1-Cd7 are incorporated and proposed as high performance near-UV photoinitiators for both the free radical polymerization (FRP) of (meth)acrylates and the cationic polymerization (CP) of epoxides utilizing Light Emitting Diodes LEDs @405 nm. Excellent polymerization-initiating abilities are found and high final reactive function conversions are obtained. Interestingly, these new derivatives display much better near-UV polymerization-initiating abilities compared to a reference UV absorbing carbazole (CARET 9H-carbazole-9-ethanol) demonstrating that the new substituents have good ability to red shift the absorption of the proposed photoinitiators. All the more strikingly, in combination with iodonium salt, Cd1-Cd7 are likewise preferred as cationic photoinitiators over the notable photoinitiator bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (BAPO) for mild irradiation conditions featuring their remarkable reactivity. In particular their utilization in the preparation of new cationic resins for LED projector 3D printing is envisioned. A full picture of the included photochemical mechanisms is given.
    Mots-clés : 3D printing, cationic polymerization, cationic-polymerization, Free radical polymerization, light emitting diodes (LEDs), Photoinitiators, resins, systems, transfer radical polymerization, visible-light.

  • Al Mousawi, A.; Kermagoret, A.; Versace, D. - L.; Toufaily, J.; Hamieh, T.; Graff, B.; Dumur, F.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Polymer Chemistry 2017, 8 (3), 568–580.
    Résumé : Copper complexes (CuCs) bearing pyridine-pyrazole ligands are synthesized and evaluated as new photoredox catalysts/photoinitiators in combination with an iodonium salt (Iod) for the free radical polymerization of (meth) acrylates and the cationic polymerization of epoxides upon visible light exposure using a Light Emitting Diode (LED)@405 nm. The structure/reactivity/efficiency relationships for the copper complexes are studied as well as the chemical mechanisms involved. The different substituents on the pyrazole moiety of the ligand allow tuning of the oxidation potential and the visible light absorbance of the complexes and to optimize the performance of the polymerization photoredox catalysts. The use of a novel additive (CARET) in a three-component system (CuC/Iod/CARET) highly improves the performance. Finally, the high performances of the Cu(I) complexes for the development of new 3D printing resins using an LED projector are demonstrated. Currently, LED projector printing is really advantageous in 3D printing i.e. this technology projects the profile of an entire layer at one time.
    Mots-clés : atom-transfer, click reactions, coordination-compounds, cu(i) complexes, cu-based sensitizers, emitting electrochemical-cells, iridium complexes, oxygen tolerance, pet-raft polymerization, transfer radical polymerization.

  • Al Mousawi, A.; Lara, D. M.; Noirbent, G.; Dumur, F.; Toufaily, J.; Hamieh, T.; Buo, T. - T.; Goubard, F.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Macromolecules 2017, 50 (13), 4913–4926.
    Résumé : This paper is devoted to the effect of a thermally activated delayed fluorescence (TADF) property in new photoinitiators/photoredox catalysts. Four carbazole derivatives A1-A4 exhibiting a TADF character are synthesized and proposed for the first time as high performance visible light photoinitiators/metal-free photoredox catalysts, in the presence of an amine or/and an iodonium salt, for both the free radical polymerization (FRP) of (meth)acrylates and the cationic polymerization (CP) of epoxides upon visible light exposure using light-emitting diodes (LEDs) at 405, 455, and 477 nm. Interestingly, the impact of the substituent effect on the excited state lifetimes and therefore on the photoinitiating ability of a series of substituted carbazoles was clearly evidenced and examined. Upon bromination of the carbazole core, clear effects on the excited state lifetimes and light absorption were demonstrated, enabling to tune the initiator performance. Excellent polymerization initiating abilities are found, and high final monomer conversions are obtained. The use of these novel carbazole-based systems in photocurable cationic formulations for LED projector 3D printing is particularly outlined. TADF molecules allow a more efficient reaction from the excited singlet state as a result of their prolonged lifetimes; i.e., this effect is well highlighted through a comparison with previously published none-TADF metal-free photoredox catalysts. A full picture of the involved photochemical mechanisms is also provided. Carbazoles exhibiting a TADF character pave the way toward metal-free photoredox catalysts active in both oxidative and reductive cycles with efficiency on par with those of the traditional metal-based photoredox catalysts/photoinitiators.
    Mots-clés : fluorophores, n-vinylcarbazole, photoinitiating systems, photopolymerization, promoted cationic-polymerization, resins, uv, visible-light.

  • Amalian, J. - A.; Poyer, S.; Petit, B. E.; Telitel, S.; Monnier, V.; Karamessini, D.; Gigmes, D.; Lutz, J. - F.; Charles, L. International Journal of Mass Spectrometry 2017, 421, 271–278.
    Résumé : MS/MS sequencing is an unrivaled technique to decipher binary information chemically encoded in the backbone of sequence-controlled synthetic polymers constructed with two co-monomers of different mass, arbitrarily designated as the 0- and 1-bit of the ASCII alphabet. Efficiency of this "reading" step relies however on the simplicity of MS/MS patterns, which depends on both polymer chemistry and chain length. In this context, polyurethanes (PUs) were very promising candidates as dissociation of small deprotonated oligomers (n \textless 8) yielded a single fragment series. The carbamate bond cleavage reaction was hence studied in details to tentatively anticipate the CID behavior of longer chains prior to optimizing their synthesis. In spite of the simplicity of MS/MS spectra, three different mechanisms were evidenced; however, they were not expected to induce MS/MS complexity when activating longer chains, as verified for sequence-controlled PUs containing up to two bytes of information (i.e., 16 co-monomers). In contrast, the ionization step appeared to be an issue: deprotonation yield of the end-group in negative ion mode electrospray was observed to strongly decrease as PU chain length increases. This sensitivity issue was addressed by introducing a second acidic end-group to allow doubly deprotonated oligomers with no impact on their CID behavior. (C) 2017 Elsevier B.V. All rights reserved.
    Mots-clés : Carbamate bond cleavage, collision-induced dissociation, containing macromolecules, Digital polymers, DNA, mass-spectrometry, MS/MS sequencing, phosphoramidite, polymers, Polyurethanes, sequence-controlled polymers, storage.

  • Berta, M.; Maria, S.; Phan, T. N. T.; Gigmes, D.; Fina, A.; Camino, G. Journal of Polymer Engineering 2017, 37 (1), 21–30.
    Résumé : Epoxy resin/montmorillonite nanocomposites were obtained via in situ intercalative polymerisation. The polymer matrix consists of anhydride-cured epoxy, and the choice of catalyst allows exchange reactions without depolymerisation. This makes the resin insoluble and reprocessable at the same time and potentially recyclable. In this study, reprocessing of the nanocomposites was done by mechanical grinding and re-welding by compression moulding at high temperature, similarly to thermoplastics. The effect of this process on the level of clay dispersion is discussed. Nanocomposite superstructures were imaged by means of transmission electron microscopy, and montmorillonite interlayer spacings were estimated by small angle X-ray scattering. The thermomechanical and combustion properties of the nanocomposites were investigated by means of dynamic mechanical thermal analysis, thermogravimetric analysis and cone calorimetry. The material tensile complex modulus E* was improved by nanocomposite formation, also after the glass transition occurred. Flammability of the material was moderately affected by the dispersed clay.
    Mots-clés : clay nanocomposites, epoxy, exfoliation, fire, montmorillonite, nanocomposite, polymer nanocomposites, thermosets, transesterification, vitrimer.

  • Bouzrati-Zerelli, M.; Zivic, N.; Dumur, F.; Gigmes, D.; Graff, B.; Fouassier, J. P.; Lalevee, J. Polymer Chemistry 2017, 8 (13), 2028–2040.
    Résumé : Eleven diketo pyrrolo-pyrrole (DKPP) derivatives have been synthesized as new high performance photo-initiators and combined with various additives to initiate the free radical polymerization of methacrylates in thin and thick films under visible violet, blue, green, and yellow light irradiation (e.g. LEDs at 405 nm, 470 nm, 477 nm, 520 nm or 565 nm) both in laminate or under air; under red light (@ 635 nm), their performance is lower. Compared to the well-known camphorquinone or Eosin based systems, most of the novel DKPP based photoinitiating systems exhibit much higher efficiencies. The photopolymerization of thick films (1.4 mm) under air is also feasible. Most of these DKPP structures exhibited excellent bleaching properties and can also be used in water-borne formulations. The photochemically generated reactive species have been investigated by steady state photolysis, cyclic voltammetry, fluorescence, laser flash photolysis and electron spin resonance spin trapping techniques.
    Mots-clés : cationic-polymerization, challenges, diketopyrrolopyrrole, efficient, electron, films, long-wavelength photosensitizer, multicolor photoinitiator, thiophene derivatives, Visible lights.

  • Colombani, J.; Chauvet, E.; Amat, S.; Dupuy, N.; Gigmes, D. Analytica Chimica Acta 2017, 960, 53–62.
    Résumé : The effects of radiation on polymeric materials are a topic of concern in a wide range of industries including the sterilization, and the nuclear power industry. While much work has concentrated on systems like polyolefins that are radiation sterilized, some work has been done on epoxy systems. The epoxy system studied is an epoxy/amine paint which is representative of the paint that covers the inner surfaces of the French nuclear reactor containment buildings. In case of a severe accident on a Nuclear Power Plant, fission products can be released from the nuclear fuel to the reactor containment building. Among them, volatile iodine (12) can be produced and can interact with the epoxy-paint. This paint is also subjected to gamma radiation damages (due to the high dose in the containment coming from radio-nuclides released from the fuel). So the epoxy-paint studied was exposed to gamma radiation under air atmosphere after being loaded with I-2 or not. The aim of this study is to characterize by FTIR spectroscopy the iodine-paint interactions, then to identify the radiation damages on the epoxy-paint, and to check their effects on these iodine-paint interactions. This work shows the potential of multi-block analysis method (ANOVA-PCA and COMDIM = AComDim) for such a study as it allows to identify the nature of iodine/epoxy-paint interactions and to characterize the gamma radiation damages on the epoxy-paint. AComDim method conduces to the extraction of Common Components to different tables and highlights factors of influence and their interactions. (C) 2017 Elsevier B.V. All rights reserved.
    Mots-clés : AComDim, anova-pca, charge-transfer complexes, degradation, epoxy coatings, Epoxy-paint, Gamma radiation, Iodine, MIR spectroscopy, molecular-iodine, phebus fp tests, phenoxy resins, radio-oxidation, severe accident simulation, short wavelengths.

  • Garra, P.; Dumur, F.; Al Mousawi, A.; Graff, B.; Gigmes, D.; Morlet-Savary, F.; Dietlin, C.; Fouassier, J. P.; Lalevee, J. Polymer Chemistry 2017, 8 (38), 5884–5896.
    Résumé : Significant improvements of the recently proposed Cu(I)/vitamin C + water/dibenzoyl peroxide (BPO) system for the redox free radical polymerization of methacrylates in air are presented here, the goal being to avoid the presence of water and to eliminate the unstable BPO compound. Additionally, the use of mechanosynthesized Cu(I) complexes bearing cheap triphenylphosphine and methylpyridine ligands, allowed us to reduce the economical and synthesis costs significantly. Water-free reducing agents such as 6-O-palmitoyl-L-ascorbic acid, organotin or hydrazine derivatives are evaluated. Cumene hydroperoxide and tert-butyl perbenzoate are proposed as a replacement for less stable BPO. Most of these novel combinations are more efficient in air than the usual amine/benzoylperoxide system (4-N, N-TMA/BPO) reference especially at the sample surface. Among them, Cu(I)/organotin/cumene hydroperoxide appears as an efficient and competitive alternative to the conventional amine/BPO couple.
    Mots-clés : confocal raman microscopy, cure, decomposition, dental resins, free-radical polymerization, mechanochemistry, methyl-methacrylate, oxygen inhibition, peroxide, photopolymerization.

  • Garra, P.; Dumur, F.; Gigmes, D.; Al Mousawi, A.; Morlet-Savary, F.; Dietlin, C.; Fouassier, J. P.; Lalevee, J. Macromolecules 2017, 50 (10), 3762–3772.
    Résumé : The free radical polymerization of low viscosity methacrylate blends upon a LED irradiation at 405 nm under air is carried out using Cu(I)/iodonium salt/tin(II) organic derivative as photoinitiating systems. The system exhibits a high reactivity; where tin derivative plays a crucial role. It operates through a catalytic cycle in which Cu(I) is regenerated and can be used at low concentrations (0.1-0.3 wt %). Remarkable performances are achieved. At first, a final methacrylate conversion of 82% after 40 s in 1.4 mm thick samples is obtained for an irradiance of 35 mW/cm(2) whereas such a conversion is only reached only when using Cu(I)/iodonium salt system under a 200 mW/cm(2) light exposure. Second, a 55% conversion is still obtained after 150 s under a very low irradiance (2.5 mW/cm(2)). Third, almost tack-free thick samples (1.4 mm) under air are produced upon sunlight exposure (65% of conversion for the 1.4 mm thick sample after 90 s of irradiation). Fourth, the photocuring of clear samples as thick as 9 cm (and presumably even more) with an impressive homogeneity through the entire polymerizable medium is feasible; the photopolymerization of 8.5 cm thick filled samples is also realized. Fifth and last, a lateral polymerization beyond the irradiated area is demonstrated with unprecedented extensions of 8 mm (tin(II) = 1.3%) and 28 mm (tin(II) = 8%), which allows polymerization reactions to occur in shadowed areas. The Chemical mechanisms are studied by steady state photolysis and ESR-spin trapping experiments. The subsequent role of the hydroperoxides (ROOH) formed during the polymerization reaction is a key point i.e. for the polymerization in shadowed areas (thick and filled samples), these latent species (ROOH) will be generated from the oxygen inhibition and can diffuse for a full curing of the samples through a ROOH/Cu(I) redox initiation.
    Mots-clés : atrp, chemistry, green, initiation, methyl-methacrylate, peroxide, photoinitiating systems, Polymerization, resins, visible-light.

  • Garra, P.; Dumur, F.; Morlet-Savary, F.; Dietlin, C.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2017, 55 (21), 3646–3655.
    Résumé : The first use of a new mechanosynthesized copper complex (Cu(acac)(2dppba)) as a initiator for the redox and redox photoactivated polymerization of methacrylates under air is proposed. This paper (i) describes the mechanosynthesis of this complex, (ii) outlines the relative efficiency of the complex for redox polymerization (mechanosynthesized product vs. solvent synthesized product), (iii) follows the polymerization enhancement under a 405 nm light, and (iv) demonstrates the high performance of this complex in near infrared photoactivated redox polymerization where a completely colorless polymer is obtained (unprecedented under NIR irradiations, 785 nm, here). The light activated polymerization exhibit higher conversions, better time controls (activation control) and higher surface conversions than redox polymerization. The mechanosynthesis is well characterized by two solvent-free methods (visual color change and Electron Spin Resonance) and two solvent-based methods (high resolution-electrospray ionization-mass spectrometry (HR-ESI-MS) and UV-vis spectrometry). The involved mechanisms are discussed. Mechanosynthesis of copper complexes opens new perspectives for copper (photo)redox polymerization catalysts as the environmental impact and economical costs of the complex synthesis are significantly reduced. (c) 2017 Wiley Periodicals, Inc.
    Mots-clés : (photo)initiators, (photo)redox catalysis, confocal raman microscopy, epr, ligands, mechanochemical synthesis, mechanosynthesis, methyl-methacrylate, nir, photosensitizers, Polymerization, resins, x-ray.

  • Garra, P.; Kermagoret, A.; Al Mousawi, A.; Dumur, F.; Gigmes, D.; Morlet-Savary, F.; Dietlin, C.; Fouassier, J. P.; Lalevee, J. Polymer Chemistry 2017, 8 (28), 4088–4097.
    Résumé : Novel copper complex based initiating systems for redox free radical polymerization (FRP) of methacrylate resins under mild conditions are proposed. Remarkably, the FRP performance of the Cu(I)/ascorbic acid (Vitamin C - VitC)/benzoyl peroxide (BPO) redox system is noticeably more significant than that of the amine/BPO reference especially at the top surface where the oxygen inhibition is particularly deleterious. The Cu(I)/BPO interaction leads to a decomposition of the peroxide and generates a benzoyl radical and Cu(II) as a byproduct. The ascorbic acid acts as a reducing agent and allows the regeneration of Cu(I) from Cu(II). Hydroperoxides formed at the surface through the radical/O-2 interaction are also decomposed by the new proposed Cu complex leading to additional polymerization initiating species. The structure/ reactivity relationship of the new proposed Cu(I) complexes in the Cu(I)/VitC/BPO systems is studied. The use of Cu(I)/VitC/BPO/iodonium salt systems in redox photoactivated FRP is also explored.
    Mots-clés : amine, bone cements, confocal raman microscopy, cure, decomposition, dental resins, free-radical polymerization, methyl-methacrylate, oxygen inhibition, reactivity.

  • Garra, P.; Dietlin, C.; Morlet-Savary, F.; Dumur, F.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Polymer Chemistry 2017, 8 (46), 7088–7101.
    Résumé : The photopolymerization processes are currently associated with thin samples for which the light penetration is good enough to activate the photoinitiator or the photoinitiating system for the entre sample's thickness. The photopolymerization of very thick films and in shadow areas where the light penetration is inhibited (e.g. in filled, pigmented, and dispersed samples) remains a huge challenge (e.g. for the access to composites). In the present paper, an overview of the different strategies for the photopolymerization of thick samples is reported. First, strategies based on the optimization of the photonic (light intensity, excitation wavelength, etc.) or chemical (efficiency/reactivity/bleaching of the photoinitiating systems, etc.) parameters are presented that result in a full temporal and spatial control. Then, the main strategies based on propagation/diffusion mechanisms of latent species for the curing beyond the irradiated areas are given (partial loss of spatial resolution and access to shadow areas). Also, dual systems (thermal/ photochemical or photochemical/redox) are described. The state of the art for the access to thick samples by photopolymerization processes as well as some perspectives are provided.
    Mots-clés : 3d printing resins, active-center lifetime, electron-paramagnetic-resonance, free-radical photopolymerization, frontal polymerization, phototriggered base proliferation, redox initiating systems, translucent fiberglass post, up-conversion particles, visible-light.

  • Ho, H. T.; Tintaru, A.; Rollet, M.; Gigmes, D.; Phan, T. N. T. Polymer Chemistry 2017, 8 (37), 5660–5665.
    Résumé : In this Communication, we report the synthesis of a series of potassium sulfonyl (trifluoromethanesulfonyl) imide (STFSI) derivatives, bearing at one extremity the STFSI group and at the other extremity either bromo, azido or amine groups. The resultant STFSI derivatives were subsequently used in the post-polymerization functionalization of (co)polymers to yield functionalized (co)polymers by exploiting the highly efficient coupling reactions, namely alkylation, amidation and alkyne-azide cycloaddition.
    Mots-clés : block-copolymers, click chemistry, electrolytes, lithium batteries, membrane, methacrylate, poly(ionic liquid)s, polymers, radical polymerization, triblock copolymers.

  • Jimenez-Sanchez, G.; Terrat, C.; Verrier, B.; Gigmes, D.; Trimaille, T. Chemical Communications 2017, 53 (57), 8062–8065.
    Résumé : An antigen probe (HIV-1 p24) immobilized onto N-succinimidyl ester based micelles was used as a solid phase coating in ELISA test, and induced a significant improvement in antibody detection sensitivity as compared to the standard free antigen coating. The relevance of this straightforward approach to improve the bioassay sensitivity was confirmed by using biotin as a generic probe.
    Mots-clés : antibodies, copolymer, diagnostics, increases, polymer.

  • Kalashnyk, N.; Mouhat, K.; Oh, J.; Jung, J.; Xie, Y.; Salomon, E.; Angot, T.; Dumur, F.; Gigmes, D.; Clair, S. Nature Communications 2017, 8, 14735.
    Résumé : In the blooming field of on-surface synthesis, molecular building blocks are designed to self-assemble and covalently couple directly on a well-defined surface, thus allowing the exploration of unusual reaction pathways and the production of specific compounds in mild conditions. Here we report on the creation of functionalized organic nanoribbons on the Ag(110) surface. C-H bond activation and homo-coupling of the precursors is achieved upon thermal activation. The anisotropic substrate acts as an efficient template fostering the alignment of the nanoribbons, up to the full monolayer regime. The length of the nanoribbons can be sequentially increased by controlling the annealing temperature, from dimers to a maximum length of about 10 nm, limited by epitaxial stress. The different structures are characterized by room-temperature scanning tunnelling microscopy. Distinct signatures of the covalent coupling are measured with high-resolution electron energy loss spectroscopy, as supported by density functional theory calculations.
    Mots-clés : covalent nanostructures, graphene nanoribbons, hydrogen, metal-surfaces, phthalocyanine, Polymerization, polymers, reactivity, terminal alkynes, wires.

  • Martrou, G.; Leonetti, M.; Gigmes, D.; Trimaille, T. Polymer Chemistry 2017, 8 (11), 1790–1796.
    Résumé : We have here developed a straightforward one-step route to surface modified polystyrene (PS) based microfibers for protein/enzyme immobilization. Our approach consists of wet electrospinning of a poly(styrene-alt-maleic anhydride) (PSMA) polymer in an aqueous solution collector which contains the (macro) molecules to be coupled, here PEG diamine (PEGDA) or hexamethylene diamine (hexDA). The amino groups on the fiber surface were then exploited for immobilization of the horseradish peroxidase (HRP) enzyme. The immobilized HRP amounts were higher on the PEG-and hexyl-modified fibers than on the non-modified PSMA ones. The HRP catalytic activity was evaluated with 2,2'-azino-bis(3-ethyl-benzothiazoline- 6-sulfonic acid) (ABTS) as a substrate. While the retained activity of the enzyme immobilized on unmodified PSMA microfibers was only 2.4% of free enzyme, that of the enzyme immobilized on the PEGylated fibers increased to 34%. As a comparison, HRP fixed on hexyl-functionalized fibers exhibited a retention activity of 19.7%, showing the impact of a PEG spacer on HRP activity. HRP immobilization on PEG and hexyl-coated fibers had also a beneficial impact on enzyme storage stability. This study highlights the impact of surface properties on the activity of the immobilized enzyme and provides a convenient route to simultaneous elaboration/modification of fibers, for suitable protein fixation.
    Mots-clés : adsorption, cellulose fibers, enzyme immobilization, fabrication, horseradish-peroxidase, hydrogen-peroxide sensor, multilayer films, nanofibers, pegylated polyurethane nanoparticles, wet.

  • Mokbel, H.; Anderson, D.; Plenderleith, R.; Dietlin, C.; Morlet-Savary, F.; Dumur, F.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Polymer Chemistry 2017, 8 (36), 5580–5592.
    Résumé : The goal of this paper concerns the development of photoinitiating systems usable in industrial processes for coating applications (cationic polymerization of epoxide based resins), the manufacture of Interpenetrating Polymer Networks (IPNs) (polymerization of acrylate/epoxy blends) and the production of thick epoxy/glass fibre composites. For these purposes, a copper photoredox catalyst, G1, is proposed as a high performance photoinitiator. It allows the design of very efficient three component photoinitiating systems (G1/iodonium salt (Iod)/N-vinylcarbazole (NVK)). The effects of the resin, light source (LED@ 375, 395, 405 nm, halogen lamp), G1 concentration, coating thickness (25 mu m and 1.4 mm), water content, formulation stability and hydrolytic stability of the cured coatings were investigated. Examples of IPNs and glass fibre composites are provided. In the studied applications the G1/Iod/NVK system is much better than BAPO/Iod/NVK (BAPO -bis(2,4,6-trimethylbenzoyl) phenylphosphine oxide -Irgacure 819) used as a reference system with good reactivity in the 365-420 nm range. Owing to the catalytic nature of G1, a reduced G1 content (30 fold less compared to the BAPO content) still leads to a higher practical efficiency than BAPO in the photopolymerization of a coating. A comparison with other reference systems based on 2-isopropylthioxanthone or anthracene is also provided and outlines again the very high performance of G1 for industrial applications.
    Mots-clés : air, cationic-polymerization, combination, complexes, initiating systems, light, monomers, photopolymerization.

  • Nehache, S.; Tyagi, P.; Semsarilar, M.; Deratani, A.; Phan, T. N. T.; Gigmes, D.; Quemener, D. Soft Matter 2017, 13 (38), 6689–6693.
    Résumé : Herein, a membrane prepared from the self-assembly of poly(styreneco-acrylonitrile)-b-poly(ethyleneoxide)-b-poly(styrene-co-acrylonitrile) micelles is found to exhibit translocation of nano-objects dispersed in aqueous solution. With the water flow as a driving force, temporary pores are created in between the micelles to facilitate the passage of nano-objects. These temporary pores close afterwards through a self-healing mechanism. As main results, polystyrene and silica nanoparticles exhibited a selective translocation directly influenced by their size and applied pressure.
    Mots-clés : adsorption, bilayer, carbon nanotubes, delivery, nanoparticles, protein, serum-albumin, surfaces.

  • Tarbe, M.; de Pomyers, H.; Mugnier, L.; Bertin, D.; Ibragimov, T.; Gigmes, D.; Mabrouk, K. Fitoterapia 2017, 120, 85–92.
    Résumé : Aconitum karacolicum from northern Kyrgyzstan (Alatau area) contains about 0.8-1% aconitine as well as other aconite derivatives that have already been identified. In this paper, we compare several methods for the further purification of an Aconitum karacolicum extract initially containing 80% of aconitine. Reverse-phase flash chromatography, reverse-phase semi-preparative HPLC, centrifugal partition chromatography (CPC) and re crystallization techniques were evaluated regarding first their efficiency to get the highest purity of aconitine (over 96%) and secondly their applicability in a semi-industrial scale purification process (in our case, 150 g of plant extract). Even if the CPC technique shows the highest purification yield (63%), the recrystallization remains the method of choice to purify a large amount of aconitine as i) it can be easily carried out in safe conditions; ii) an aprotic solvent is used, avoiding aconitine degradation. Moreover, this study led us to the identification of lappaconitine in Aconitwn karacolicum, a well-known alkaloid never found in this Aconttum species.
    Mots-clés : Aconinun karacolicum, Aconitine, Aconitine degradation, alkaloids, counter-current chromatography, Lappaconitine, Plant extract, Purification methods, separation.

  • Tardy, A.; Honore, J. - C.; Siri, D.; Nicolas, J.; Gigmes, D.; Lefay, C.; Guillaneuf, Y. Polymer Chemistry 2017, 8 (34), 5139–5147.
    Résumé : The current study reports on the kinetic analysis of the free-radical polymerization of several seven-membered cyclic ketene acetal monomers and in particular 2-methylene-1,3-dioxepane (MDO) and 5,6-benzo-2-methylene-1,3-dioxepane (BMDO). Such monomers are known to undergo a complete ring-opening to afford polyester chains by a radical pathway. The influence of experimental conditions (e.g., nature and concentration of the initiator, temperature, solvent, etc.) on the kinetics and molar mass distribution was studied. Whereas it was shown that BMDO cannot be polymerized using peroxides due to H-abstraction, the experimental results also demonstrated that the polymerization kinetics were strongly driven by the nature of the propagating radical, with reactivity order: MDO \textgreater BMDO \textgreater 4,7-dimethyl-5,6-benzo-2(chloromethyl)-1,3-dioxepane (MeBMDO). The copolymerization of MDO and BMDO (1 : 1) was also investigated. The incorporation of both monomers was identical but the polymerization kinetics were governed by the monomer with the lowest reactivity. The experimental results were finally rationalized by the combination of DFT calculations of the propagation rate constants with PREDICI modelings.
    Mots-clés : 2-methylene-1, 3-dioxepane, 5, 6-benzo-2-methylene-1, copolymers, limitations, mechanism, methacrylate, polyester, rate coefficients, ring-opening polymerization, styrene.

  • Tardy, A.; Honore, J. - C.; Tran, J.; Siri, D.; Delplace, V.; Bataille, I.; Letourneur, D.; Perrier, J.; Nicoletti, C.; Maresca, M.; Lefay, C.; Gigmes, D.; Nicolas, J.; Guillaneuf, Y. Angewandte Chemie-International Edition 2017, 56 (52), 16515–16520.
    Résumé : Free-radical copolymerization of cyclic ketene acetals (CKAs) and vinyl ethers (VEs) was investigated as an efficient yet simple approach for the preparation of functional aliphatic polyesters. The copolymerization of CKA and VE was first predicted to be quasi-ideal by DFT calculations. The theoretical prediction was experimentally confirmed by the copolymerization of 2-methylene-1,3-dioxepane (MDO) and butyl vinyl ether (BVE), leading to r(MDO) = 0.73 and r(BVE) = 1.61. We then illustrated the versatility of this approach by preparing different functional polyesters: 1) copolymers functionalized by fluorescent probes; 2) amphiphilic copolymers grafted with poly(ethylene glycol) (PEG) side chains able to self-assemble into PEGylated nanoparticles; 3) antibacterial films active against Gram-positive and Gram-negative bacteria (including a multiresistant strain); and 4) cross-linked bioelastomers with suitable properties for tissue engineering applications.
    Mots-clés : 2-methylene-1, 3-dioxepane, aliphatic polyesters, biodegradable polyesters, biomaterials, biomedical applications, caprolactone, click chemistry, combination, copolymerization, cyclic ketene acetals, degradable polymers, DFT calculations, functional polyesters, ring-opening polymerization.

  • Tardy, A.; Nicolas, J.; Gigmes, D.; Lefay, C.; Guillaneuf, Y. Chemical Reviews 2017, 117 (3), 1319–1406.
    Résumé : Cyclic monomers bearing either vinyl or exomethylene groups have the ability to be polymerized through a radical pathway via a ring-opening mechanism (addition fragmentation process), leading to the introduction of functionalities in the polymer backbone. Radical ring-opening polymerization (rROP) combines the advantages of both ring-opening polymerization and radical polymerization, that is the preparation of polymers bearing heteroatoms in the backbone but with the ease and robustness of a radical process. This current review presents a comprehensive description of rROP by detailing: (0 the various monomers that polymerize through rROP; (ii) the main parameters that govern the rROP mechanism; (iii) the copolymerization by conventional or controlled/living radical polymerization between rROP monomers and traditional vinyl monomers to obtain copolymers with advanced properties; (iv) the different applications (low shrinkage materials and pieparation of (bio)degradable materials) of rROP monomer-containing materials, and (v) the main alternatives to rROP to induce degradability to materials obtained by a radical polymerization.
    Mots-clés : conventional vinyl monomers, cyclic ketene acetals, fragmentation chain transfer, functional degradable polymers, holographic data-storage, intracellular drug-delivery, methacrylate) based polymers, Nitroxide-mediated polymerization, poly(4-hydroxystyrene)s main-chain, tissue engineering applications.

  • Tehfe, M. - A.; Lepeltier, M.; Dumur, F.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Macromolecular Chemistry and Physics 2017, 218 (18), 1700192.
    Résumé : A series of 18 iridium complexes (Ir) have been prepared and studied. Their abilities to initiate both a ring-opening cationic polymerization (CP) using an Ir/iodonium salt couple and a free radical polymerization (FRP) in the presence of an Ir/amine/alkyl halide system under very soft irradiation (i.e., halogen lamp) or upon exposure to laser diodes @457 nm and @532 nm are investigated. Interestingly, these photoinitiating systems operate through an oxidative or a reductive photoredox catalytic cycle, respectively. Excellent polymerization profiles are obtained (reactive function conversions \textgreater70% for the CP of an epoxide and \textgreater60% for the FRP of low viscosity triacrylate). The photochemical mechanisms are studied by fluorescence, steady state photolysis, cyclic voltammetry, and electron spin resonance spin trapping experiments.
    Mots-clés : atom-transfer, atrp, cationic-polymerization, electron, Free radical polymerization, initiator, iridium complexes, led, metal, photocatalysis, photopolymerization, radical polymerization, ring-opening cationic polymerization (ROP), systems.

  • Yin, H.; Dumur, F.; Niu, Y.; Ayhan, M. M.; Grauby, O.; Liu, W.; Wang, C.; Siri, D.; Rosas, R.; Tonetto, A.; Gigmes, D.; Wang, R.; Bardelang, D.; Ouari, O. Acs Applied Materials & Interfaces 2017, 9 (38), 33220–33228.
    Résumé : This work describes latent fluorescence particles (LFPs) based on a new environmentally sensitive carbazole compound aggregated in water and their use as sensors for probing various cavitands and the different stages of aggregating systems. Cyclodextrins (CDs), cucurbit[n]urils (CB[n], n = 6, 7,'8), and a resorcinarene capsule were used to study the dynamic nature of the LFPs. The fluorescence was dramatically enhanced by a proposed disaggregation-induced emission enhancement (DIEE) mechanism with specific features for CB [n]. Then, the aggregated states of the dipeptides Leu-Leu, Phe-Phe, and Fmoc-Leu-Leu (vesicles, crystals, fibers) were studied by fluorescence spectroscopy and confocal fluorescence microscopy thanks to the adaptive and emissive behavior of the LFPs, allowing us to study an interesting polymorphism phenomenon. The LFPs have then been used in the sensing of the aggregation of the polysaccharide alginate, for which distinct fluorescence turn-on is detected upon stepwise biopolymer assembly, and for amylose detection. The carbazole particles not only adapt to various environments but also display multicolor fluorescent signals. They can be used for the fast probing of the aggregation propensity of newly prepared molecules or biologically relevant compounds or to accelerate the discovery of new macrocycles or of self-assembling peptides in water.
    Mots-clés : assemblies, binding, chameleonic dye, cucurbit[n]urils, disaggregation-induced emission enhancement, emission, fluorescent dyes, fluorophore, host-guest complexes, latent fluorescence particles, light, nanostructures, peptide aggregation, polysaccharide aggregation, quantum dots, water.
2016

  • Ay, E.; Raad, Z.; Dautel, O.; Dumur, F.; Wantz, G.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Macromolecules 2016, 49 (6), 2124-2134.
    Résumé : In the present paper, four fluorescent materials currently used in organic light emitting diodes (OLEDs) are presented in an original way as high performance photocatalysts usable in polymerization photoinitiating systems. Their performance is excellent in free radical polymerization, cationic polymerization but also in the synthesis of interpenetrating polymer networks (IPNs). A coherent picture of the chemical mechanisms involved in these new photo catalytic systems is provided. Remarkably, an oligomeric and copolymerizable photocatalyst (PVD2) is proposed here for the first time, i.e., both the high molecular weight of PVD2 and the presence of reactive double bonds as end groups (which could be involved in a copolymerization reaction) ensure a very low migration of the catalyst from the synthesized polymer.

  • Ayari-Riabi, S.; Trimaille, T.; Mabrouk, K.; Bertin, D.; Gigmes, D.; Benlasfar, Z.; Zaghmi, A.; Bouhaouala-Zahar, B.; Elayeb, M. Vaccine 2016, 34 (15), 1810-1815.
    Résumé : Scorpion envenoming represents a public health issue in subtropical regions of the world. Treatment and prevention need to promote antitoxin immunity. Preserving antigenic presentation while removing toxin effect remains a major challenge in toxin vaccine development. Among particulate adjuvant, particles prepared with poly (D,L-lactide) polymer are the most extensively investigated due to their excellent biocompatibility and biodegradability. The aim of this study is to develop surfactant-free PLA nanoparticles that safely deliver venom toxic fraction to enhance specific immune response. PLA nanoparticles are coated with AahG50 (AahG50/PLA) and BotG50 (BotG50/PLA): a toxic fraction purified from Androctonus australis hector and Buthus occitanus tunetanus venoms, respectively. Residual toxicities are evaluated following injections of PLA-containing high doses of AahG50 (or BotG50). Immunization trials are performed with the detoxified fraction administered alone without adjuvant. A comparative study of the effect of Freund is also included. The neutralizing capacity of sera is determined in naive mice. Six months later, immunized mice are challenged subcutaneously with increased doses of AahG50. Subcutaneous lethal dose 50 (LD50) of AahG50 and BotG50 is of 575 mu g/kg and 1300 mu g/kg respectively. By comparison, BotG50/PLA is totally innocuous while 50% of tested mice survive 2875 mu g AahG50/kg. Alhydrogel and Freund are not able to detoxify such a high dose. Cross-antigenicity between particulate and soluble fraction is also, ensured. AahG50/PLA and BotG50/PLA induce high antibody levels in mice serum. The neutralizing capacity per mL of anti-venom was 258 mu g/mL and 186 mu g/mL calculated for anti-AahG50/PLA and anti-BotG50/PLA sera, respectively. Animals immunized with AahG50/PLA are protected against AahG50 injected dose of 3162 mu g/kg as opposed all non-immunized mice died at this dose. We find that the detoxification approach based PLA nanoparticles, benefit the immunogenicity and protective efficacy of venom immunogen. (C) 2016 Elsevier Ltd. All rights reserved.
    Mots-clés : adjuvants, alpha-toxins, antigenicity, Detoxification, immunogenicity, Immunoprotection, Neutralization, PLA nanoparticles, protection, Toxic venom fraction.

  • Broggi, J.; Rollet, M.; Clement, J. - L.; Canard, G.; Terme, T.; Gigmes, D.; Vanelle, P. Angewandte Chemie-International Edition 2016, 55 (20), 5994-5999.
    Résumé : Polymerization reactions with organic electron donors (OED) as initiators are presented herein. The metal-free polymerization of various activated alkene and cyclic ester monomers was performed in short reaction times, under mild conditions, with small amounts of organic reducing agents, and without the need for co-initiators or activation by photochemical, electrochemical, or other methods. Hence, OED initiators enabled the development of an efficient, rapid, room-temperature process that meets the technical standards expected for industrial processes, such as energy savings, cost-effectiveness and safety. Mechanistic investigations support an electron-transfer initiation pathway that leads to the reduction of the monomer.
    Mots-clés : 2-electron transfer, anionic-polymerization, carbanionic polymerization, chain-growth polymerization, electron transfer, free-radical polymerization, methyl-methacrylate, n-heterocyclic carbenes, organic electron donors, reaction mechanisms, reduction, ring-opening polymerization, single-electron, tetraazafulvalene.

  • Chendo, C.; Le, D.; Phan, T. N. T.; Gigmes, D.; Charles, L. Journal of Polymer Science Part a-Polymer Chemistry 2016, 54 (20), 3388-3397.
    Résumé : An analytical workflow involving high resolution mass analysis, collision-induced dissociation and ion mobility was implemented to structurally characterize polymeric by-products detected in lieu of intact species when performing matrix-assisted laser desorption/ionization (MALDI) of polystyrenes with fragile end groups. Studied samples were prepared by atom transfer radical polymerization, reversible addition-fragmentation transfer polymerization and nitroxide-mediated polymerization. Spectral resolution enabled by orthogonal injection of MALDI ions into a reflectron time-of-flight mass analyzer allowed a thorough inventory of species, including some with the same nominal m/z value but different elemental composition. Individual end-group mass determination was achieved in MS/MS experiments, implementing an additional separative dimension based on ion mobility prior to CID to assist precursor ion selection in case of interferences. Besides validating commonly reported polystyrene chains terminated with either endo- or exo-double bond, this multidimensional approach permitted to show that initiating moiety could also be affected by the MALDI process. (c) 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 3388-3397
    Mots-clés : atrp, capped polystyrene, Controlled radical polymerization, easy access, end-groups, initiators, ion mobility, liquid-chromatography, maldi-ms, mo(iii)/mo(iv), oxide)/polystyrene block-copolymer, Polystyrene, styrene, synthetic-polymers, tandem mass spectrometry.

  • Chendo, C.; Phan, T. N. T.; Marque, S. R. A.; Gigmes, D.; Charles, L. International Journal of Mass Spectrometry 2016, 405, 50-58.
    Résumé : Reactive MALDI was evidenced to occur when using acidic matrices to assist ionization of poly(4-vinylpyridine) (P4VP) prepared by nitroxide mediated polymerization (NMP). The high accessibility of nitrogen atoms in each 4VP units would allow strong hydrogen bonding with acidic matrix molecules, which was shown to further weaken the fragile C-ON linkage between the last monomeric unit and the nitroxide end-group. As a result, release of the nitroxide upon laser irradiation of the MALDI sample would lead to radical chains capable of reacting with the matrix molecule in interaction with the last 4VP unit, yielding a new polymeric by-product where one matrix molecule is incorporated in the chain termination. The mechanism proposed for this reaction was supported by accurate mass measurements, MS/MS data as well as electron paramagnetic resonance (EPR) experiments. Interestingly, such matrix/polymer covalent adducts were no longer observed when using MALDI source operated at high vacuum. (C) 2016 Elsevier B.V. All rights reserved.
    Mots-clés : assisted-laser-desorption/ionization, Covalent matrix adduct, dynamics model, free sample preparation, ionization, labile end-groups, Mass spectrometry, matrix, mechanism, on bond homolysis, P4VP, Poly(4-vinylpyridine), Reactive MALDI, sinapinic acid, Synthetic polymer, tof ms.

  • Dumur, F.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Accounts of Chemical Research 2016, 49 (9), 1980-1989.
    Résumé : Photoinitiated polymerization has been the subject of continued research efforts due to the numerous applications in which this polymerization technique is involved (coatings, inks, adhesives, optoelectronic, laser imaging, stereolithography, nanotechnology, etc.). More recently, photopolymerization has received renewed interest due to the emergence of 3D-printing technologies. However, despite current academic and industrial interest in photopolymerization methodologies, a major limitation lies in the slow rates of photopolymerization. The development of new photoinitiating systems aimed at addressing this limitation is an active area of research. Photopolymerization occurs through the exposure of a curable formulation to light, generating radical and/or cationic species to initiate polymerization. At present, photopolymerization is facing numerous challenges related to safety, economic and ecological concerns. Furthermore, practical considerations such as the curing depth and the competition for light absorption between the chromophores and other species in the formulation are key parameters drastically affecting the photopolymerization process. To address these issues, photoinitiating systems operating under low intensity visible light irradiation, in the absence of solvents are highly sought after. In this context, the use of photoredox catalysis can be highly advantageous; that is, photoredox catalysts can provide high reactivities with low catalyst loading, permitting access to high performance photoinitiating systems. However, to act as efficient photoredox catalysts, specific criteria have to be fulfilled. A strong absorption over the visible range, an ability to easily oxidize or reduce as well as sufficient photochemical stability are basic prerequisites to make these molecules desirable candidates for photoredox catalysis. Considering the similarity of requirements between organic electronics and photopolymerization, numerous materials initially designed for applications in organic electronics have been revisited in the context of photopolymerization. Organic electronics is a branch of electronics and materials science focusing on the development of semiconductors devoted to three main research fields; organic light-emitting diodes (OLEDs), organic field-effect transistors (OFETs), and organic solar cells (OSCs). The contribution of organic electronics to the field of electronics is important as it paves the way toward cheaper, lighter, and more energy efficient devices. In the present context of photopolymerization, materials that were investigated as photocatalysts were indifferently organic semiconductors used for transistors, charge-transport materials, and light-emitting materials used in electroluminescent devices or conjugated polymers and small molecule dyes for solar cells. In this Account, we summarize our latest developments in elaborating on photocatalytic systems based on these new classes of compounds. Through an in-depth understanding of the parameters governing their reactivities and our efforts to incorporate these materials into photoinitiating systems, we provide new knowledge and a valuable insight for future prospects.
    Mots-clés : ancillary ligands, cyclometalated iridium(iii) complexes, green-light, high-performance, ir(iii) complexes, light-emitting devices, Photoinitiating systems, transfer radical polymerization, visible-light, zinc-complexes.

  • Gunay, U. S.; Petit, B. E.; Karamessini, D.; Al Ouahabi, A.; Amalian, J. - A.; Chendo, C.; Bouquey, M.; Gigmes, D.; Charles, L.; Lutz, J. - F. Chem 2016, 1 (1), 114-126.
    Résumé : Polyurethanes (PUs) constitute a popular class of plastic materials with a wide range of applications in construction, coatings, and the automotive industry. PUs are usually synthesized by step-growth polymerization and, therefore, exhibit non-uniform molecular structures. Here, we show that uniform PUs can be prepared by a facile chemoselective multistep-growth approach. This strategy permits precise control of the chain lengths of the PUs formed and their primary structure, thus making the preparation of coded monomer sequences possible. Furthermore, it was found that these polymers are remarkably easy to analyze by tandem mass spectrometry sequencing. Thus, these precision polymers can potentially be used as molecular barcodes in various applications. As a proof of concept, their use as anti-counterfeiting tags for identification of materials is reported here.
    Mots-clés : block, chemistry, design, encoded poly(alkoxyamine amide)s, information-containing macromolecules, oligomers, phase synthesis, polymers.

  • Kermagoret, A.; Gigmes, D. Tetrahedron 2016, 72 (48), 7672-7685.
    Résumé : Nitroxide mediated radical polymerization (NMP) is one of the most powerful method for advanced polymer synthesis. However, NMP suffers from some limitations, in particular to mediate the polymerization of unconjugated monomers or to conduct the polymerization of conjugated monomers under low temperatures. The combination of NMP with other reversible-deactivation radical polymerization techniques, such as reversible addition fragmentation chain transfer (RAFT), atom transfer radical polymerization (ATRP) or organometallic mediated radical polymerization (OMRP), offered new possibilities in macromolecular engineering. In this contribution we report different strategies of 'combined NMP', i.e., the exchange of the polymer chain-end controlling agents for sequenced polymerization or the introduction of different polymerization-initiating sites onto alkoxyamines or polymers. (C) 2016 Elsevier Ltd. All rights reserved.
    Mots-clés : Alkoxyamine, atom-transfer, Combined polymerization, hydrogen-transfer reaction, labile end-groups, methyl-methacrylate, mixed homopolymer brushes, n-butyl acrylate, Nitroxide mediated polymerization, poly(methyl methacrylate)/polystyrene brushes, poly(tert-butyl acrylate)/polystyrene brushes, Polymer synthesis, Reversible-deactivation radical polymerization, ring-opening polymerization, silica nanoparticles.

  • Le, D.; Phan, T. N. T.; Autissier, L.; Charles, L.; Gigmes, D. Polymer Chemistry 2016, 7 (8), 1659-1667.
    Résumé : A series of carboxylic acid-based alkoxyamines associated with SnBr4, a Lewis acid, have been used as protonic acids of a binary initiating system to control the cationic polymerization of vinyl ether. The living character of the homopolymerization of isobutyl vinyl ether was investigated under various conditions (solvent, amount of catalyst, initiator structure etc.). Among the different studied dual initiators, TEMPO based-alkoxyamine showed high efficiency to lead the polymerization of isobutyl vinyl ether (IBVE) in a controlled manner. The prepared polymers exhibited high TEMPO functionality (> 0.85) and low dispersity (1.2) which is essential for the synthesis of well-defined block copolymers thereafter. TEMPO-functionalized PIBVE was used as a macro-initiator controller in the nitroxide-mediated polymerization (NMP) of styrene at 130 degrees C leading successfully to well-defined block copolymers of poly(isobutyl vinyl ether)-b-polystyrene (PIBVE-b-PS) with a narrow dispersity (1.2).

  • Lepeltier, M.; Graff, B.; Lalevee, J.; Wantz, G.; Ibrahim-Ouali, M.; Gigmes, D.; Dumur, F. Organic Electronics 2016, 37, 24-34.
    Résumé : Two cationic iridium (III) complexes [Ir(dfppy)(tpy)(bpy)](PF6) and [Ir(dfppy)(tpy)(phen)](PF6) bearing three different ligands were tested as triplet emitters for Light-Emitting Electrochemical Cells (LECs). These two phosphorescent materials only constitute the third and fourth examples of triple heteroleptic cationic iridium complexes to be tested in electroluminescent devices. LECs fabricated with this almost unknown class of iridium complex furnished green-emitting devices. Parallel to investigations devoted to electroluminescent properties, photophysical and electrochemical properties of the two new complexes were examined. Density functional theory calculations were also performed to provide insight into the electronic structure of the two emitters. (C) 2016 Elsevier B.V. All rights reserved.
    Mots-clés : ancillary ligands, blue-green, cyclometalated iridium(iii), efficient blue, Electroluminescence, electroluminescent devices, ionic liquids, Ionic liquid, Iridium complex, Lifetime, Light-emitting electrochemical cells, phosphorescent, photopolymerization, Red, transition-metal-complexes.

  • Mokbel, H.; Dumur, F.; Raveau, B.; Morlet-Savary, F.; Simonnet-Jegat, C.; Gigmes, D.; Toufaily, J.; Hamieh, T.; Fouassier, J. P.; Lalevee, J. Tetrahedron 2016, 72 (48), 7686-7690.
    Résumé : Four perovskites (LaTiO3, LaCrO3, La0.6Sr0.4MnO3 and MAPbl(3)) are proposed here as new photoinitiators (e.g., free radical generators) in combination with iodonium salt and optionally another additive (N-vinylcarbazole-NVK) to initiate both radical and cationic photopolymerization reactions. The proposed systems are efficient phenyl radical generators under polychromatic light sources such as a halogen lamp or a Xe-Hg lamp. The interest of this approach is the ability to work with very stable inorganic structures as photoinitiators. To the best of our knowledge, this is the first time that perovskites are incorporated in photoinitiating systems. Photochemical mechanisms will be proposed as sustained by electron spin resonance spin trapping (ESR-ST) experiments. (C) 2016 Elsevier Ltd. All rights reserved.
    Mots-clés : Cationic polymerization, crystal-chemistry, efficient, Free radical initiators, giant magnetoresistance, initiating systems, n-vinylcarbazole, oxides, Perovskites, Photoinitiator, photopolymerization, Polychromatic light, Polymerization, sensitized solar-cell, state, visible-light.

  • Mokbel, H.; Poriel, C.; Rault-Berthelot, J.; Dumur, F.; Gigmes, D.; Toufaily, J.; Hamieh, T.; Cordella, D.; Detrembleur, C.; Fouassier, J. P.; Lalevee, J. Journal of Applied Polymer Science 2016, 133 (12), 43213.
    Résumé : d A novel photoinitiator based on a spiroxanthene scaffold in the presence of an iodonium salt is proposed for the cationic ring-opening polymerization of a diepoxide, as well as for the free-radical polymerization of an acrylate upon violet LED exposure (385 and 405 nm). Good-to-excellent rates of polymerization and final conversions are obtained. These systems are characterized by a higher reactivity compared with that of anthracene/iodonium salt used as reference for cationic near UV polymerization. The addition of a poly(ionic liquid) improves the cationic polymerization profiles. The photochemical mechanisms are studied by steady-state photolysis, fluorescence, and electron spin resonance spin-trapping techniques. Molecular orbital calculations give an insight into the light absorption properties. (C) 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43213.

  • Rollet, M.; Pelletier, B.; Berek, D.; Maria, S.; Phan, T. N. T.; Gigmes, D. Journal of Chromatography A 2016, 1462, 63-72.
    Résumé : Liquid Chromatography under Limiting Conditions of Desorption (LC LCD) is a powerful separation tool for multicomponent polymer systems. This technique is based on a barrier effect of an appropriate solvent, which is injected in front of the sample, and which decelerates the elution of selected macromolecules. In this study, the barrier effects have been evaluated for triblock copolymers polystyrene-b-poly(ethylene oxide)-b-polystyrene (PS-b-PEO-b-PS) according to the content of polystyrene (wt% PS) and PEO-block molar mass. PS-b-PEO-b-PS samples were prepared by Atom Transfer Radical Polymerization (ATRP). The presence of respective parent homopolymers was investigated by applying optimized LC LCD conditions. It was found that the barrier composition largely affects the efficiency of separation and it ought to be adjusted for particular composition range of block copolymers. (C) 2016 Elsevier B.V. All rights reserved.
    Mots-clés : adsorption, Barriers efficiency, complex polymers, diblock copolymers, electrolytes, Liquid chromatography under limiting conditions of desorption, Nitroxide-mediated polymerization, Polystyrene-b-poly(ethylene oxide)-b-polystyrene, size-exclusion chromatography, Triblock copolymers.

  • Telitel, S.; Dumur, F.; Campolo, D.; Poly, J.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2016, 54 (5), 702-713.
    Résumé : This article reports on the presumably first use of iron complexes (FeC) as potential photocatalysts for controlled radical photopolymerization reactions (CRP2). Three compounds were designed and investigated. Good linear evolutions of the molecular weight (Mn) with the conversion were observed. A comparison was provided with a reference iridium (III) complex [Ir(ppy)3 where ppy stands for 2-phenylpyridine]. The on/off photopolymerization experiments highlight the presence of dormant species and a re-initiation on demand upon irradiation. This unique re-initiation property was used for the modification of surfaces (hydrophilic/hydrophobic properties) and surface patterning as well as the synthesis of a block co-polymer (PMMA-b-PBA). A comparative analysis of the behavior of these iron complexes in thermally and photochemically activated polymerization was provided. The chemical mechanisms were studied by steady state photolysis, laser flash photolysis, cyclic voltammetry, luminescence quenching, and electron spin resonance experiments. A catalytic cycle was proposed with two steps: (i) the oxidation of the FeC excited state by an alkyl halide and (ii) the reduction by the oxidized form (FeC degrees+) by an amine or the macroradicals leading to the regeneration of the catalyst. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 702-713

  • Trimaille, T.; Pertici, V.; Gigmes, D. Comptes Rendus Chimie 2016, 19 (1-2), 157-166.
    Résumé : In spinal cord repair, the challenge consists in combining various therapies that account for multiple deleterious effects in order to induce an efficient recovery. In that context, biomaterial implantation seems to be highly relevant. Indeed, biomaterials not only serve as a growth support to promote sectioned axonal fibers, but are also used for cell transplantation and drug delivery. In this review, we discuss and put into perspective the recent results obtained in the field of spinal cord repair by synthetic hydrogel implantation. The versatility of those biomaterials is presented through the latest chemical strategies developed to enhance their therapeutic effects. (C) 2015 Academie des sciences. Published by Elsevier Masson SAS. This is an open access article under the CC BY-NC-ND license.
    Mots-clés : axonal regeneration, Bioadhesion, biomaterials, block-copolymers, cell-adhesion, central-nervous-system, Degradability, Drug delivery, drug-delivery, functional recovery, injury repair, polymers, reverse thermal gel, Scaffolds, Spinal cord injury, Synthetic hydrogel.

  • Verdoni, M.; Roudaut, H.; De Pomyers, H.; Gigmes, D.; Bertin, D.; Luis, J.; Bengeloune, A. H.; Mabrouk, K. Bioorganic & Medicinal Chemistry 2016, 24 (22), 5685-5692.
    Résumé : To discover new molecules with an inhibitory activity of melanogenesis a hundred of scorpions, snakes, spiders and amphibians venoms were screened for their capacity to inhibit mushroom tyrosinase using 3,4-L-dihydroxyphenylalanine (L-DOPA) as substrate. The Argiope lobata spider venom proved to be the most active. HPLC fraction containing Argiotoxine-636 (ArgTX-636), a polyamine known for its numerous biological activities, was found to also show a good regulation activity of melanogenesis by inhibiting DOPA and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) oxidases activities, wore by tyrosinase (TYR) and tyrosinase-related protein 1 (TRP-1), respectively. Our results demonstrate that ArgTX-636 reduced the mushroom tyrosinase activity in a dose dependent way with a maximal half inhibitory concentration (IC50) value of 8.34 mu M, when L-DOPA is used as substrate. The Lineweaver-Burk study showed that ArgTX-636 is a mixed type inhibitor of the diphenolase activity. Moreover, ArgTX-636 inhibits DHICA oxydase activity of mushroom tyrosinase activity with IC50 at 41.3 mu M. ArgTX-636 has no cytotoxicity in B16F10 melanoma cells at concentrations up to 42.1 mu M. The effect of ArgTX-636 on melanogenesis showed that melanin production in B16F10 melanoma cell decreased by approximatively 70% compared to untreated cells. ArgTX-636 displayed no significant effect on the TYR expression while the protein level of TRP-1 decreased in B16F10 cells. Thus, ArgTX-636 could have particular interest for cosmetic and/or pharmaceutical use in order to reduce important dermatoses in black and mixed skins. (C) 2016 Elsevier Ltd. All rights reserved.
    Mots-clés : 5,6-dihydroxyindole-2-carboxylic acid, Argiotoxine, ArgTX-636, DHICA oxydase activity, DOPA oxydase activity, Hyperpigmentation, melanocytes, Melanogenesis, oxidase activity, receptors, Spider venoms, Tyrosinase, Tyrosinase related protein 1 (TRP-1).

  • Zhang, J.; Campolo, D.; Dumur, F.; Xiao, P.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2016, 54 (14), 2247-2253.
    Résumé : The development of iron complexes for the photoredox catalysis is a huge challenge. Indeed, Iron complexes can be ideal candidates due to their potential visible light absorption and redox properties but also because they are less toxic, inexpensive and environmentally friendly compared to other catalysts. In the present paper, a series of novel iron complexes have been synthesized and utilized to initiate the free radical promoted cationic polymerization of epoxides or the free radical polymerization of acrylates through photoredox catalysis processes upon exposure to near UV (385 nm) or visible violet (405 nm) light emitting diodes (LEDs). When combined with an iodonium salt and N-vinylcarbazole, the iron complex-based photoinitiating systems are able to generate radicals, cations, and radical cations. The initiation efficiency is investigated through real-time Fourier transform infrared spectroscopy and a satisfactory initiating ability is found. The mechanisms for the generation of the reactive initiating species through photoredox catalysis are studied by different methods (steady state photolysis, cyclic voltammetry and electron spin resonance spin trapping techniques) and discussed in detail. (C) 2016 Wiley Periodicals, Inc.
    Mots-clés : amine system, arene complex, atom-transfer, Cationic photopolymerization, epoxy polymerization, fragmentation chain transfer, iridium complexes, iron complexes, LEDs, n-vinylcarbazole, photoinduced electron-transfer, Photoinitiator, Photoinitiators, photopolymerization reactions, Radical photopolymerization.

  • Zhang, J.; Campolo, D.; Dumur, F.; Xiao, P.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Chemcatchem 2016, 8 (13), 2227-2233.
    Résumé : The novel role of metal-based complexes as photoinitiator catalysts fits well into the concept of green chemistry, as it realizes the activation of polymer synthesis processes by visible light that are abundant in the solar light and allows the marked reduction of photoinitiator amount in the systems. In the present paper, a series of iron complexes (FeC_x) with various ligands have been proposed as new photoinitiator catalysts to initiate the cationic polymerization of epoxides or the free radical polymerization of acrylates upon a near-UV or visible-light LED exposure. The ligands play an important role on the light absorption properties and the photoinitiation ability of the iron complexes. In combination with one or two additives, FeC_x are capable to efficiently generate radicals, cations, and radical cations through an oxidative or a reductive path. Two of the newly developed FeC_x-based photoinitiating systems exhibited comparable photoinitiation efficiency with the commercial TypeI photoinitiator bis(2,4,6-trimethylbenzoyl)phenylphosphineoxide (BAPO). Owing to the photocatalytic effect, remarkable photoinitiation efficiencies have been achieved by using very low concentration of iron complexes (0.02 wt%) in the systems. The involved photochemical mechanisms have been studied using electron spin resonance spin trapping, steady state photolysis, cyclic voltammetry, and laser flash photolysis techniques.
    Mots-clés : aldehydes, cationic-polymerization, Dyes, free-radical photopolymerization, green chemistry, iridium complexes, iron, ligand effects, n-vinylcarbazole, organocatalysis, photocatalysis, Photochemistry, Polymerization, solar-cells, versatile photoinitiators.

  • Zhang, J.; Campolo, D.; Dumur, F.; Xiao, P.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Polymer Bulletin 2016, 73 (2), 493-507.
    Résumé : A carbazole-bound ferrocenium salt [i.e., (eta(6)-Carbazole) (eta(5)-cyclopentadienyl) iron hexafluorophosphate-FS] is proposed as an efficient photoinitiator for the cationic ring-opening polymerization of epoxides under air upon the exposure to a near-UV LED at 385 nm or a visible LED at 405 nm. When using this ferrocenium salt FS (0.2 wt%)/diphenyliodonium hexafluorophosphate or FS (0.2 wt%)/diphenyliodonium hexafluorophosphate/N-vinylcarbazole, final epoxide conversions of 55-66 % can be obtained after 800 s of irradiation at 385 or 405 nm. Reference cationic photoinitiators (i.e., diphenyliodonium hexafluorophosphate; 9-(4-hydroxyethoxyphenyl) thianthrenium hexafluorophosphate and triphenylsulfonium hexafluorophosphate) are unable to initiate the epoxide polymerization under the same conditions. The photochemical mechanisms for the formation of the initiating species are studied using steady-state photolysis, cyclic voltammetry, laser flash photolysis and electron spin resonance spin-trapping techniques. Molecular orbital calculations help to describe the absorption properties and the initiation step. The performance attained when using FS alone is really promising for applications under soft near-UV or visible light-emitting diode irradiation.

  • Zhang, J.; Dumur, F.; Horcajada, P.; Livage, C.; Xiao, P.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Macromolecular Chemistry and Physics 2016, 217 (22), 2534-2540.
    Résumé : Photoinitiating systems consisting of a highly porous iron(III)-based metal-organic framework (MOF), an iodonium salt, and N-vinylcarbazole are developed to initiate the free radical promoted cationic polymerization of epoxides under air and the free radical polymerization of acrylates in laminate upon exposure to near UV (385 nm) or visible (405 nm) light-emitting diodes. These systems present a satisfactory initiating ability. Among the five tested iron carboxylate MOFs exhibiting different compositions and topologies, the flexible microporous iron(III) terephthalate MIL53 is particularly interesting, leading to a final conversion of 58% for the ring-opening polymerization of epoxides. This provides the possibility of designing MOF/polymer composite materials with enhanced mechanical properties through the in situ incorporation of the MOF structure during the photopolymerization process.
    Mots-clés : catalysis, Cationic photopolymerization, light, metal-organic framework, mil-100(fe), oxide, photocatalyst, Photoinitiator, Photoinitiators, Radical photopolymerization.

  • Zhang, J.; Dumur, F.; Xiao, P.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2016, 54 (9), 1189-1196.
    Résumé : The cations and radicals produced in aminothiazonaphthalic anhydride derivatives (ATNAs) combined with an iodonium salt, N-vinylcarbazole, amine, or chloro triazine initiate the ring-opening cationic polymerization of epoxides and the free radical polymerization of acrylates under LEDs at 405 or 455 nm. The photoinitiating ability of these novel photoinitiating systems is higher than that of the well-known camphor-quinone-based systems. An example of the high reactivity of the new proposed photoinitiator is also provided in resins for 3D-printing using a LED projector@405 nm. The chemical mechanisms are investigated by steady-state photolysis, cyclic voltammetry, fluorescence, laser flash photolysis, and electron spin resonance spin-trapping techniques. (C) 2015 Wiley Periodicals, Inc.

  • Zhang, J.; Xiao, P.; Dumur, F.; Guo, C.; Hong, W.; Li, Y.; Gigmes, D.; Graff, B.; Fouassier, J. - P.; Lalevee, J. Macromolecular Chemistry and Physics 2016, 217 (19), 2145-2153.
    Résumé : A series of conjugated polymers and oligomers previously used in organic photovoltaics and organic light-emitting diodes ( OLEDs) have been examined for the first time as photoinitiators of polymerization. They address the present and future challenges facing photopolymerization: requirement of high extinction molar coefficients, absorption over the whole visible spectrum, ability to easily withdraw or release electrons. Interestingly, these compounds initiate the cationic polymerization of epoxides or the free radical polymerization of acrylates upon exposure of the photocurable formulations to a LED emitting at 405 nm. Some of them can potentially operate under blue, green, or red laser diodes.
    Mots-clés : Acrylate, atom-transfer, bulk heterojunction, derivatives, design, epoxide, led, naphthalimide, organic solar-cells, Photoinitiator, photopolymerization, polymer, power-conversion efficiency, ptb7, radical polymerization.

  • Zivic, N.; Zhang, J.; Bardelang, D.; Dumur, F.; Xiao, P.; Jet, T.; Versace, D. - L.; Dietlin, C.; Morlet-Savary, F.; Graff, B.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Polymer Chemistry 2016, 7 (2), 418-429.
    Résumé : A series of naphthalimide derivatives containing tertiary amine groups (DNNDs) have been prepared. Some of these derivatives (e.g. DNND3, DNND4 and DNND5) exhibit interesting shifted absorption so that they can be utilized as versatile photoinitiators upon exposure to various violet and blue LEDs (385, 405, 455 and 470 nm). They are particularly efficient for the cationic photopolymerization of an epoxide and the free radical photopolymerization of an acrylate. The thiol-ene photopolymerization, as well as the synthesis of interpenetrating polymer networks (of epoxide/acrylate blend) IPNs, is feasible. Remarkably, the production of hydrogels can also be easily achieved using a DNND derivative after inclusion in a cyclodextrin cavity. The photochemical mechanisms have been comprehensively investigated by steady state photolysis, Electron Spin Resonance (ESR), fluorescence, electrochemistry and laser flash photolysis and discussed in detail.
2015


  • Belekian, D.; Beyou, E.; Chaumont, P.; Cassagnau, P.; Flat, J. J.; Quinebèche, S.; Guillaneuf, Y.; Gigmes, D. European Polymer Journal 2015, 66, 342-351.
    Résumé : The effect of a nitroxyl-based radical scavenger (tretramethyl piperidino radicals, TEMPO or indolynoxyl radicals, DPAIO) on the course of the melt radical grafting of maleic anhydride (MA) onto polyethylene has been explored. The reaction was conducted at 160 °C in a mini-extruder with 2,5-dimethyl-2,5-di(tertiobutylperoxy)hexane (Luperox 101-C16H34O4; L101) as hydrogen abstractor. Optimal experimental conditions were defined by varying both L101 concentration and L101/nitroxide molar ratio. The degree of grafting of MA was determined by infra-red spectroscopy and was as high as 0.26 wt.% and 0.34 wt.% in presence of TEMPO and DPAIO respectively.
    Mots-clés : DPAIO, Maleic anhydride, Polyethylene, Radical melt grafting, TEMPO.

  • Chendo, C.; Moreira, G.; Tintaru, A.; Posocco, P.; Laurini, E.; Lefay, C.; Gigmes, D.; Viel, S.; Pricl, S.; Charles, L. Journal of the American Society for Mass Spectrometry 2015, 26 (9), 1483-1493.
    Résumé : Anomerization of simple sugars in the liquid phase is known as an acid- and base-catalyzed process, which highly depends on solvent polarity. This reaction is reported here to occur in the gas phase, during traveling wave ion mobility spectrometry (TWIMS) experiments aimed at separating alpha- and beta-anomers of penta-acrylated glucose generated as ammonium adducts in electrospray ionization. This compound was available in two samples prepared from glucose dissolved in solvents of different polarity, namely tetrahydrofuran (THF) and N,N-dimethylacetamide (DMAC), and analyzed by electrospray tandem mass spectrometry (ESI-MS/MS) as well as traveling wave ion mobility (ESI-TWIMS-MS). In MS/MS, an anchimerically-assisted process was found to be unique to the electrosprayed alpha-anomer, and was only observed for the THF sample. In ESI-TWIMS-MS, a signal was measured at the drift time expected for the alpha-anomer for both the THF and DMAC samples, in apparent contradiction to the MS/MS results, which indicated that the alpha-anomer was not present in the DMAC sample. However, MS/MS experiments performed after TWIMS separation revealed that ammonium adducts of the alpha-anomer produced from each sample, although exhibiting the same collision cross section, were clearly different. Indeed, while the alpha-anomer actually present in the THF sample was electrosprayed with the ammonium adducted at the C2 acrylate, its homologue only observed when the DMAC sample was subjected to TWIMS hold the adducted ammonium at the C1 acrylate. These findings were explained by a beta/alpha inter-conversion upon injection in the TWIMS cell, as supported by theoretical calculation and dynamic molecular modeling.


  • Chendo, C.; Rollet, M.; Phan, T. N. T.; Viel, S.; Gigmes, D.; Charles, L. International Journal of Mass Spectrometry 2015, 376, 90-96.
    Résumé : The position of nitrogen atoms in poly(4-vinylpyridine) (P4VP), compared to their poly(2-vinylpyridine) (P2VP) isomers, explains most difficulties faced when determining their molecular weight parameters by size exclusion chromatography, due to oligomers strongly adsorbing onto stationary phases. The high accessibility of these nitrogen atoms is shown here to be challenging also in matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), probably accounting for the lack of mass data reported for P4VP in the literature. Using a “bottom-up” strategy starting from small oligomers prior to consider high molecular weight polymers, P4VP species were observed here to strongly interact with acidic matrix molecules such as 2,5-DHB when preparing MALDI sample using the traditional dried-droplet procedure. In contrast, MALDI best performed when using a solvent-free sample preparation involving a non-acidic matrix such as DCTB. Accordingly, reliable MS determination of molecular weight parameters could be achieved for P4VP up to about 40 kDa, as validated by diffusion NMR experiments.
    Mots-clés : MALDI, Mass spectrometry, P4VP, Poly(4-vinylpyridine), Solvent-free preparation, Synthetic polymer.

  • Delplace, V.; Guegain, E.; Harrisson, S.; Gigmes, D.; Guillaneuf, Y.; Nicolas, J. Chemical Communications 2015, 51 (64), 12847-12850.
    Résumé : 2-Methylene-4-phenyl-1,3-dioxolane (MPDL) was successfully used as a controlling comonomer in NMP with oligo(ethylene glycol) methyl ether methacrylate (MeOEGMA) to prepare well-defined and degradable PEG-based P(MeOEGMA-co-MPDL) copolymers. The level of ester group incorporation is controlled, leading to reductions in molecular weight of up to 95% on hydrolysis. Neither the polymer nor its degradation products displayed cytoxicity. The method was also successfully applied to methyl methacrylate.

  • Delplace, V.; Guegain, E.; Harrisson, S.; Gigmes, D.; Guillaneuf, Y.; Nicolas, J. Chemical Communications 2015, 51 (66), 13146-13146.

  • Devaux, D.; Gle, D.; Phan, T. N. T.; Gigmes, D.; Giroud, E.; Deschamps, M.; Denoyel, R.; Bouchet, R. Chemistry of Materials 2015, 27 (13), 4682-4692.
    Résumé : Safety is one of the most important criteria for electrochemical energy storage devices used in large scale applications such as wind or solar farms. In this context, solid polymer electrolytes based on nanostructured block copolymer electrolytes (BCEs) are promising because their properties can be finely tuned by adjusting simultaneously their block chemistries and polymer architectures. However, there is a need to rationalize the different properties of BCE that are optimal for battery applications. We produced by controlled radical polymerization a large number of BCEs based on either (1) linear poly(ethylene oxide) (PEO) or (2) comb PEO as the ionic conductor block, and polystyrene as the structural block. We varied the molecular weight of the PEO-based block, the composition, and the architecture (diblock vs triblock). We performed a systematic analysis of their thermodynamic, ionic transport, and mechanical properties. To verify the potential of BCEs as electrolytes, we evaluated their electrochemical stabilities. Laboratory scale batteries comprising the best BCEs and LiFePO4 as a positive active material were cycled at different rates and temperatures. This process allows the selection of the best architectures and compositions that had been successfully tested in battery prototypes and cycled for more than 600 cycles at high rates without any dendritic growth.

  • Dumur, F.; Beouch, L.; Peralta, S.; Wantz, G.; Goubard, F.; Gigmes, D. Organic Electronics 2015, 25, 21-30.
    Résumé : A new carbazole-based polymer PEPEK varying from the previously reported PEPK by the length of the spacer between the polymer backbone and the pendent carbazole moiety was investigated as polymeric host for solution-processed devices. Interestingly, if the two polymers are structurally close since the length of the alkyl chain only differs from one carbon atom, the previously reported PEPK gave higher performances than the newly synthesized PEPEK when tested as host for the wide bandgap triplet emitter FIrpic. To optimize electroluminescence performances, two device configurations were examined. On doping the emissive layer of phosphorescent organic light-emitting devices (OLEDs) at 16 wt% with FIrpic, best PEPK-based OLEDs gave an efficacy of 15.14 cd/A whereas PEPEK-based devices furnished an efficiency of 12.17 cd/A in the same conditions. To determine the origin of this unexpected behavior, the new polymer PEPEK was characterized by UV-visible absorption and luminescence spectroscopy as well as cyclic voltammetry. Thermal properties of PEPEK were also examined and compared to those of PEPK. (C) 2015 Elsevier B.V. All rights reserved.

  • Guegain, E.; Delplace, V.; Trimaille, T.; Gigmes, D.; Siri, D.; Marque, S. R. A.; Guillaneuf, Y.; Nicolas, J. Polymer Chemistry 2015, 6 (31), 5693-5704.
    Résumé : The functionalization of alkoxyamines prior to nitroxide-mediated polymerization (NMP) induces important structural variations when compared to the parent molecules. This may have important consequences on the design of functionalized materials by pre-functionalization. In this context, a wide range of amide-functionalized alkoxyamines (a functionality often obtained after conjugation from COOH- and N-succinimidyl-containing alkoxyamines) based on the nitroxide SG1 (N-tert-butyl-N-(1-diethyl phosphono-2,2-dimethylpropyl) nitroxide) have been synthesized and their dissociation rate constants (k(d)) have been determined. To rationalize their reactivity, a multi-parameter procedure was applied and enabled to discriminate disubstituted amide-functionalized alkoxyamines from monosubstituted ones. Monosubstituted alkoxyamines exhibited lower k(d) than their disubstituted counterparts (E-a increase of similar to 7-10 kJ mol(-1)) because of the occurrence of intramolecular hydrogen bonding (IHB) between the alkyl and the nitroxide fragments. NMP of styrene, n-butyl acrylate and methyl methacrylate with a small amount of acrylonitrile was then successfully performed from two representative secondary SG1-based alkoxyamines employed for conjugation: namely AMA (COOH-containing) and AMA-NHS (N-succinimidyl derivative), and compared to polymerizations initiated with AMA-Gem, an AMA-based alkoxyamine pre-functionalized with the anticancer drug Gemcitabine (Gem) and subjected to IHB. Although AMA-NHS showed the best results due to its lower Ea, the strong polarity of the Gem moiety that counter-balanced the detrimental effect of IHB over its kd still allowed for a reasonable control.

  • Jimenez-Sanchez, G.; Pavot, V.; Chane-Haong, C.; Handke, N.; Terrat, C.; Gigmes, D.; Trimaille, T.; Verrier, B. Pharmaceutical Research 2015, 32 (1), 311-320.
    Résumé : Activation of immune cells through pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs) or NOD-like receptors (NLRs), has been identified as a key issue in the development of new efficient vaccine adjuvants. We report here on the elaboration and immunostimulatory potential of polylactide (PLA)-based micelles core-loaded with imiquimod TLR7 ligand and able to be further surface-functionalized with antigenic protein (HIV-1 Gag p24) for antigen delivery purpose. Micelles prepared from poly(D,L-lactide)-b-poly(N-acryloxysuccinimide-co-N-vinylpyrrolidone) amphiphilic copolymer were incubated in the presence of imiquimod, leading to 1.2 wt% loading, and further conjugated to p24 antigen through reaction of p24 lysines and N-terminal amine with the N-succinimidyl pendant groups of the micelle corona. The impact of imiquimod encapsulation in the micelles on its immunostimulatory properties was investigated in vitro, by monitoring: (i) the NF-kappa B and mitogen-activated protein kinases (MAPK) pathways through experiments with RAW-Blue (TM) cells, a mouse macrophage cell line encoding an NF-kappa B/AP-1-inducible reporter construct; (ii) human dendritic cells (DCs) maturation markers by flow cytometry. RAW-Blue (TM) cells based experiments showed that imiquimod encapsulated in the micelles was much more efficient to activate the NF-kappa B and MAPK pathways than free imiquimod. Furthermore, encapsulated imiquimod was found to induce much higher maturation of DCs than the free analog. Finally, these immunostimulatory properties of the loaded imiquimod were shown to be conserved when the p24 antigen was coupled at the micelle surface. Taken together, these data regarding improved immunostimulatory efficiency suggest the strong potential of our micelle-based nano-system for vaccine delivery.

  • Le, D.; Ziarelli, F.; Phan, T. N. T.; Mollica, G.; Thureau, P.; Aussenac, F.; Ouari, O.; Gigmes, D.; Tordo, P.; Viel, S. Macromolecular Rapid Communications 2015, 36 (15), 1416-1421.
    Résumé : High-field dynamic nuclear polarization (DNP) has emerged as a powerful technique for improving the sensitivity of solid-state NMR (SSNMR), yielding significant sensitivity enhancements for a variety of samples, including polymers. Overall, depending upon the type of polymer, the molecular weight, and the DNP sample preparation method, sensitivity enhancements between 5 and 40 have been reported. These promising enhancements remain, however, far from the theoretical maximum (>1000). Crucial to the success of DNP SSNMR is the DNP signal enhancement (epsilon(DNP)), which is the ratio of the NMR signal intensities with and without DNP. It is shown here that, for polymers exhibiting high affinity toward molecular oxygen (e.g., polystyrene), removing part of the absorbed (paramagnetic) oxygen from the solid-state samples available as powders (instead of dissolved or dispersed in a solvent) increases proton nuclear relaxation times and epsilon(DNP), hereby providing up to a two-fold sensitivity increase (i.e., a four-fold reduction in experimental time).


  • Lepeltier, M.; Gigmes, D.; Dumur, F. Synthetic Metals 2015, 199, 360-364.
    Résumé : Two homoleptic iridium(III) complexes Ir3F and Ir6F were synthesized and tested as wide bandgap organometallic hosts for green phosphorescent OLEDs. While using Ir(ppy)3 as the green triplet emitter, Ir3F-based devices clearly outperformed similar devices fabricated with the traditional CBP host. On the opposite, Ir6F-based devices showed lower performances than the reference device. As appealing feature, Ir6F-based devices showed almost no efficiency roll-off i.e., no reduction of the luminous efficiency with the current density contrarily to that commonly observed for phosphorescent OLEDs.
    Mots-clés : Electroluminescence, Iridium complex, OLED, Phosphorescence, Triplet state.


  • Lepeltier, M.; Morlet-Savary, F.; Graff, B.; Lalevée, J.; Gigmes, D.; Dumur, F. Synthetic Metals 2015, 199, 139-146.
    Résumé : Two heteroleptic iridium complexes were synthesized and their photophysical properties studied. The two complexes vary by their ancillary ligand that is respectively acetylacetone (acac) or dibenzoylmethane (dbm). Interestingly, only the acac-based complex proved to be highly emissive and electroluminescent devices were only fabricated with this complex. In order to determine the emissive properties of this new complex, comparison with complexes previously reported in the literature was established.
    Mots-clés : Acetylacetone, Electroluminescence, Iridium complex, OLED, Phosphorescence, Triplet state.


  • Lepeltier, M.; Xiao, P.; Graff, B.; Morlet-Savary, F.; Gigmes, D.; Lalevée, J.; Dumur, F. Synthetic Metals 2015, 204, 48-56.
    Résumé : Three heteroleptic iridium(III) complexes comprising 1-methyl-3-propyl-5-(2,4,5-trifluorophenyl)-1H-1,2,4-triazole (tfpt) as the cyclometalated ligand and varying by their ancillary ligands were examined as triplet emitters for Phosphorescent OLEDs. Interestingly, major differences in device performances were obtained with these three isostructural complexes comprising dibenzoylmethane (dbm), acetylacetone (acac) or pyridine-2-carboxylic acid (pic) as the ancillary ligands. Best OLEDs were fabricated with the dibenzoylmethane-based iridium(III) complex. On the opposite, the picolinate and the acetylacetonate-based complexes gave moderate performances. To complement this work, theoretical calculations were carried out on the three complexes. The newly synthesized complex i.e., Ir(tfpt)(pic) was also characterized by UV–vis absorption and luminescence spectroscopy as well as cyclic voltammetry.
    Mots-clés : Electroluminescence, Iridium complex, OLED, Phosphorescence, Triazole.


  • Lessard, B. H.; Beouch, L.; Goubard, F.; Wantz, G.; Marić, M.; Gigmes, D.; Dumur, F. Organic Electronics 2015, 17, 377-385.
    Résumé : Poly(2-(N-carbazolyl)ethyl acrylate), a poly(acrylate) comprised of carbazole-side groups attached via a flexible chain to the polymer backbone (PVAK) has been tested as host for solution-processed polymer light-emitting devices (PLEDs). This non-conjugated polymer proved to be an excellent candidate to host wide-bandgap phosphors. Notably, this polymer exhibited a high thermal stability (Td = 322 °C), a glass transition temperature (Tg) of 91 °C and a wide bandgap corresponding to the pendent carbazole units and the disrupted π-conjugation of the polymer main chain, making this polymeric host a suitable candidate for wide bandgap triplet emitters. When tested as a host for FIrpic and Ir(ppy)3, the resulting blue and green light-emitting devices showed a maximum luminous efficiency of 18.25 and 17.74 cd/A, respectively, which are comparable to recent reports of devices made using other carbazole-based oxygen-rich polymeric hosts. The polymer was also characterized by UV–visible absorption, photoluminescence spectroscopy as well as cyclic voltammetry.
    Mots-clés : Acrylate, Blue dopants, Carbazole, Electroluminescence, Iridium complex, Polymer LED.

  • Mertz, G.; Fouquet, T.; El Ahrach, H. I.; Becker, C.; Phan, T. N. T.; Ziarelli, F.; Gigmes, D.; Ruch, D. Plasma Processes and Polymers 2015, 12 (11), 1293-1301.
    Résumé : Biocompatible plasma polymers are expected to be used in various applications in medicine such as drug delivery with a controlled release. In this context we investigated the possibility to monitor the kinetic of hydrolytic degradation of plasma polymers by tailoring the chemistry of the precursor. A homemade precursor way synthesized by grafting acrylate function on both side of a polycaprolactone diol (PCL diol) to produce a PCL diacrylate characterized by IR, NMR, and MS to confirm its chemical structure. Acrylates constitute a promising class of precursors to improve the retention of the integrity of the precursor by working in soft plasma conditions. The plasma polymerization of the so-synthesized precursor have been highlighted by means of a multi technique analytical strategy and ensured the retention of hydrolyzable ester function of the precursor. Finally the thickness consumption during immersion in PBS were performed and found to be slower as compared to the degradation kinetic of a plasma polymerized methacrylic anhydride.

  • Mokbel, H.; Toufaily, J.; Hamieh, T.; Dumur, F.; Campolo, D.; Gigmes, D.; Fouassier, J. P.; Ortyl, J.; Lalevee, J. Journal of Applied Polymer Science 2015, 132 (46), 42759.
    Résumé : Two iodonium salts based on a coumarin chromophore are investigated for polymerization upon light emitting diode irradiations (LEDs). They work as one-component photoinitiators. They initiate the cationic polymerization of epoxides (under air) and vinylethers (laminate) upon exposure to violet LEDs (385 and 405 nm). Excellent polymerization profiles are recorded. Their efficiency is quite similar to that of a ferrocenium salt. Interpenetrating polymer networks can also be obtained through a concomitant cationic/radical photopolymerization of an epoxy/acrylate blend monomer. The light absorption properties of these new salts as well as the involved photochemical mechanisms are investigated for the first time through electron spin resonance, laser flash photolysis, steady state photolysis experiments. Molecular orbital calculations are also used to shed some light on the initiation mechanisms. (c) 2015 Wiley Periodicals, Inc.

  • Mokbel, H.; Xiao, P.; Simonnet-Jegat, C.; Dumur, F.; Gigmes, D.; Toufaily, J.; Hamieh, T.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2015, 53 (8), 981-989.
    Résumé : Four novel onium salts (onium-polyoxometalate) have been synthesized and characterized. They contain a diphenyliodonium or a thianthrenium (TH) moiety and a polyoxomolybdate or a polyoxotungstate as new counter anions. Outstandingly, these counter anions are photochemically active and can sensitize the decomposition of the iodonium or TH moiety through an intramolecular electron transfer. The phenyl radicals generated upon

  • Moreira, G.; Fedeli, E.; Ziarelli, F.; Capitani, D.; Mannina, L.; Charles, L.; Viel, S.; Gigmes, D.; Lefay, C. Polymer Chemistry 2015, 6 (29), 5244-5253.
    Résumé : Cellulose acetate-g-polystyrene (CA-g-PS) grafted copolymers have been synthesized by nitroxide-mediated polymerization (NMP) under homogeneous conditions by using the 1,2-intermolecular radical addition (1,2-IRA) methodology to introduce the SG1-based alkoxyamine BlocBuilder MA (BB) on the polysaccharide backbone. A preliminary study conducted on model sugar-based alkoxyamines proved that whatever the position of the alkoxyamine on the sugar unit, the number of sugar units and the presence of OH groups, one could expect a controlled/living polymerization process. This was confirmed by the graft polymerization of styrene from the BB-modified cellulose acetate backbone with two different grafting ratios (3 and 20%) and different grafted chain lengths (40 000 and 80 000 g mol(-1) targeted M-n). The grafted copolymers were carefully analyzed, in particular, by DOSY NMR to confirm their grafted structure.

  • Morris, J. C.; Walsh, L. A.; Gomes, B. A.; Gigmes, D.; Fairfull-Smith, K. E.; Bottle, S. E.; Blinco, J. P. Rsc Advances 2015, 5 (116), 95598-95603.
    Résumé : The current study reports the synthesis and properties of a novel isoindoline nitroxide containing a benzophenone chromophore fused into the carbon framework. When exposed to UV light, rather than undergoing traditional benzophenone photochemical pathways, the presence of the nitroxide enables an energy transfer process whereby the nitroxide enters an excited state which induces an efficient hydrogen atom transfer from unactivated alkanes.

  • Morris, J.; Telitel, S.; Fairfull-Smith, K. E.; Bottle, S. E.; Lalevee, J.; Clement, J. - L.; Guillaneuf, Y.; Gigmes, D. Polymer Chemistry 2015, 6 (5), 754-763.
    Résumé : The combination of thermally-and photochemically-induced polymerization using light sensitive alkoxy-amines was investigated. The thermally driven polymerizations were performed via the cleavage of the alkoxyamine functionality, whereas the photochemically-induced polymerizations were carried out either by nitroxide mediated photo-polymerization (NMP2) or by a classical type II mechanism, depending on the structure of the light-sensitive alkoxyamine employed. Once the potential of the various structures as initiators of thermally-and photo-induced polymerizations was established, their use in combination for block copolymer syntheses was investigated. With each alkoxyamine investigated, block copolymers were successfully obtained and the system was applied to the post-modification of polymer coatings for application in patterning and photografting.

  • Pereira, B. de F. A.; Tardy, A.; Monnier, V.; Guillaneuf, Y.; Gigmes, D.; Charles, L. Rapid Communications in Mass Spectrometry 2015, 29 (23), 2302-2308.
    Résumé : RATIONALE: In order to prevent side reactions while developing new polymerization processes, their mechanism has to be understood and one first key insight is the structure of the end-groups in polymeric by-products. The synthetic method scrutinized here is the nitroxide-mediated polymerization (NMP) of a cyclic ketene acetal, a promising alternative process to the production of polyesters. METHODS: Polymer end-group characterization was performed by mass spectrometry (MS), combining elemental composition information derived from accurate mass data in the MS mode with fragmentation features recorded in the MS/MS mode. Electrospray was used as the ionization method to ensure the integrity of original chain terminations and a quadrupole time-of-flight (QTOF) instrument was employed for high-resolution mass measurements in both MS and tandem mass spectrometry (MS/MS) modes. RESULTS: Occurrence of side reactions in the studied polymerization method, first evidenced by an unusual increase in dispersity with conversion, was confirmed in MS with the detection of two polymeric impurities in addition to the expected species. Fragmentation rules were first established for this new polyester family in order to derive useful structural information from MS/MS data. In addition to a usual NMP by-product, the initiating group of the second polymeric impurities revealed the degradation of the nitroxide moiety. CONCLUSIONS: Unambiguous MS/MS identification of end-groups in by-products sampled from the polymerization medium allowed an unusual side reaction to be identified during the NMP preparation of polyesters. On-going optimization of the polymerization method aims at preventing this undesired process. Copyright (C) 2015 John Wiley & Sons, Ltd.


  • Poggi, E.; Guerlain, C.; Debuigne, A.; Detrembleur, C.; Gigmes, D.; Hoeppener, S.; Schubert, U. S.; Fustin, C. - A.; Gohy, J. - F. European Polymer Journal 2015, 62, 418-425.
    Résumé : A poly(vinyl alcohol)-block-poly(acrylic acid)-block-poly(4-vinylpyridine) triblock terpolymer (PVOH-b-PAA-b-P4VP) is prepared by hydrolyzing a poly(vinyl acetate)-block-poly(acrylonitrile)-block-poly(4-vinylpyridine) precursor (PVAc-b-PAN-b-P4VP) synthesized by a combination of cobalt-mediated radical polymerization (CMRP) and nitroxide mediated polymerization (NMP). The PVOH-b-PAA-b-P4VP terpolymer is further micellized in water and the accordingly obtained micellar structures are characterized by a combination of dynamic light scattering (DLS) and cryo-transmission electron microscopy (cryo-TEM) as a function of pH. Well-defined micelles are observed in the whole pH range except for pH values below 4.5 where non-aggregated chains (unimers) are present. The formation of micelles can be rationalized by the formation of insoluble PAA/P4VP inter-polyelectrolyte complexes in the 4.5–6 pH range while hydrophobic P4VP cores are observed at pH values above 6. Finally, the effect of the addition of different salts on the micellar characteristic features is investigated.
    Mots-clés : Block copolymer micelles, Cobalt mediated radical polymerization, Dynamic light scattering, Nitroxide mediated polymerization, Stimuli-responsive micelles, Triblock copolymers.


  • Rollet, M.; Pelletier, B.; Altounian, A.; Berek, D.; Maria, S.; Phan, T. N. T.; Gigmes, D. Journal of Chromatography A 2015, 1392, 37-47.
    Résumé : We studied molar mass limits for the LC LCD separation of parent polystyrene (PS) and poly(ethylene oxide) (PEO) homopolymers from PEO/PS based block copolymers and we identified optimized chromatographic conditions. Time delays between barriers and sample injections were 0–2–3′10. Eluent was composed of dimethylformamide (DMF) 40 wt.% and 1-chlorobutane (CLB) 60 wt.%; Barrier 1 (B1), which retained block copolymer, was composed of 100 wt.% CLB and Barrier 2 (B2), which retained PEO, was a mixture of DMF and CLB, which proportions were adjusted to studied block copolymers. With B2 composed of DMF 23 wt.% and CLB 77 wt.%, we obtained successful separation of PS23K-b-PEO35K-b-PS23K (56.5 wt.% of PS, the subscripts indicate the molar mass in kg mol−1 of each polymer part in the block copolymer) from its parent homopolymers. With B2 adjusted to DMF 30 wt.% and CLB 70 wt.%, PS2.3K-b-PEO3.1K (42.6 wt.% of PS) was also efficiently separated from its parent homopolymers.
    Mots-clés : Block copolymer, Liquid chromatography under limiting conditions of desorption, Method optimization, Poly(ethylene oxide), Polystyrene.

  • Telitel, S.; Telitel, S.; Bosson, J.; Lalevee, J.; Clement, J. - L.; Godfroy, M.; Fillaut, J. - L.; Akdas-Kilig, H.; Guillaneuf, Y.; Gigmes, D.; Soppera, O. Langmuir 2015, 31 (36), 10026-10036.
    Résumé : We report on the use of an alkoxyamine (AA) for fabrication of functional micropattems with complex structures by UV mask lithography. The living character of the polymer surface and the vertical spatial control of the repolymerization reaction from few tens of nanometers to few micrometers were demonstrated. The impact of the main parameters governing the controlled polymerization and the reinitiation process activated by light or heat was investigated. Micropatteming is shown to be a powerful method to investigate the physicochemical molecular phenomena. It is possible to control the polymer microstructure thickness from few tens of nanometers to few micrometers. In the last section, some applications are provided showing the potential of the AA for generating covalently bonded hydrophilic/hydrophobic micropatterns or luminescent high versatility and interest of this route. surfaces. This demonstrates the

  • Xiao, P.; Dumur, F.; Graff, B.; Zhang, J.; Morlet-Savary, F.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2015, 53 (4), 567-575.
    Résumé : Isoquinolinone derivatives (IQ) have been synthesized and combined with different additives (an amine, 2,4,6-tris(trichloromethyl)-1,3,5-triazine, an iodonium salt, or N-vinylcarbazole) to produce reactive species (i.e. radicals and cations) being able to initiate the radical polymerization of acrylates, the cationic polymerization of epoxides, the thiol-ene polymerization of trifunctional thiol/divinylether, and the synthesis of epoxide/acrylate interpenetrated polymer network IPN upon exposure to very soft polychromatic visible lights, blue laser diode or blue LED lights. Compared with the use of camphorquinone based systems, the novel combinations employed here ensures higher monomer conversions (approximate to 50-60% vs. approximate to 15-35%) and better polymerization rates in radical polymerization. The chemical mechanisms are studied by steady-state photolysis, fluorescence, cyclic voltammetry, laser flash photolysis, and electron spin resonance spin trapping techniques. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 567-575

  • Xiao, P.; Dumur, F.; Zhang, J.; Bouzrati-Zerelli, M.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2015, 53 (15), 1806-1815.
    Résumé : Isoquinolinone derivatives bearing amino- or nitro- substituent (IQNs) have been synthesized as photoinitiators and combined with various additives (i.e., iodonium salt, N-vinylcarbazole, amine or 2,4,6-tris(trichloromethyl)-1,3,5-triazine) to initiate ring-opening cationic polymerizations (CP) or free radical polymerizations under exposure to visible LEDs (e.g., LEDs at 405 nm or 455 nm, or cold white LED) or a halogen lamp. Compared to the well-known camphorquinone-based systems, the novel IQNs-based combinations employed here demonstrate higher efficiencies for the CP of epoxides. The photochemically generated reactive species (i.e., cations and radicals) from the IQNs-based systems have been investigated by steady state photolysis, cyclic voltammetry, fluorescence, laser flash photolysis, and electron spin resonance spin trapping techniques. The structure/reactivity/photoinitiating ability relationships of IQNs-based combinations are also discussed; the crucial role of the excited state lifetimes of the photoinitiators to ensure efficient quenching by additives is clearly underlined. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1806-1815

  • Xiao, P.; Dumur, F.; Zhang, J.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2015, 53 (5), 665-674.
    Résumé : Naphthalimide-phthalimide derivatives (NDPDs) have been synthesized and combined with an iodonium salt, N-vinylcarbazole, amine or 2,4,6-tris(trichloromethyl)-1,3,5-triazine to produce reactive species (i.e., radicals and cations). These generated reactive species are capable of initiating the cationic polymerization of epoxides and/or the radical polymerization of acrylates upon exposure to very soft polychromatic visible lights or blue lights. Compared with the well-known camphorquinone based systems used as references, the novel NDPD based combinations employed here demonstrate clearly higher efficiencies for the cationic polymerization of epoxides under air as well as the radical polymerization of acrylates. Remarkably, one of the NDPDs (i.e., NDPD2) based systems is characterized by an outstanding reactivity. The structure/reactivity/efficiency relationships of the investigated NDPDs were studied by fluorescence, cyclic voltammetry, laser flash photolysis, electron spin resonance spin trapping, and steady state photolysis techniques. The key parameters for their reactivity are provided. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 665-674

  • Xiao, P.; Dumur, F.; Zhang, J.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Polymer Chemistry 2015, 6 (7), 1171-1179.
    Résumé : Four different 2-amino-1H-benzo[de]isoquinoline-1,3(2H)-dione derivatives (NDNs) bearing nitro-or amino-substituents have been prepared and incorporated into photoinitiating systems together with an iodonium salt, N-vinylcarbazole, an amine or 2,4,6-tris(trichloromethyl)-1,3,5-triazine. The ring-opening cationic polymerization of epoxides as well as the free radical polymerization of acrylates upon exposure to various visible LEDs (e.g. LEDs at 405 nm, 455 nm or 470 nm) could be performed. Reactions under green or red light (e.g. laser diodes at 532 or 635 nm) are also feasible. Compared to the well-known camphorquinone-based systems, some of the novel NDN-based combinations employed here exhibit a much higher polymerization efficiency. A panchromatic behavior can also be observed with a specifically designed compound bearing two nitro groups (e.g. radical polymerization or thiol-ene processes can be promoted upon blue, green or red light). This outstanding performance paves the way to polymerization under soft conditions. Their photochemical properties and structure/efficiency relationships have been investigated using steady state photolysis, fluorescence, cyclic voltammetry, laser flash photolysis, and electron spin resonance spin trapping techniques.

  • Xiao, P.; Dumur, F.; Zhang, J.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Macromolecular Chemistry and Physics 2015, 216 (17), 1782-1790.
    Résumé : Naphthalimide derivatives (NDAs) with amino- or alkylthio-substituents have been synthesized and combined in photoinitiating systems (PIS) with an iodonium salt, N-vinylcarbazole, an amine, or 2,4,6-tris(trichloromethyl)-1,3,5-triazine to produce radicals, cation radicals, or cations. The photochemical mechanisms are investigated by fluorescence, cyclic voltammetry, laser flash photolysis, electron spin resonance spin trapping, and steady state photolysis techniques. The generated reactive species are capable of initiating the cationic polymerization (CP) of epoxides under air or the free radical polymerization (FRP) of acrylates in laminate upon exposure to visible lights delivered by a halogen lamp, a cold white light-emitting diode (LED), or LEDs at 385, 395, 405, 455, or 470 nm. Compared to the well-known camphorquinone based systems, the novel NDA containing PISs exhibit higher efficiencies both for CP and FRP. Remarkably, the photobleaching of some NDAs is significant, and colorless final polymer coatings are obtained. The structure/photochemical property relationships of NDAs are discussed in detail (redox potentials, fluorescence, rate constants of reactions, etc.) to shed some light on their respective photoinitiating ability.

  • Xiao, P.; Dumur, F.; Zhang, J.; Graff, B.; Morlet-Savary, F.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2015, 53 (24), 2860-2866.
    Résumé : Only one naphthalic anhydride derivative has been reported as light sensitive photoinitiator, this prompted us to further explore the possibility to prepare a new family of photoinitiators based on this scaffold. Therefore, eight naphthalic Naphthalic anhydride derivatives (ANH1-ANH8) have been prepared and combined with an iodonium salt (and optionally N-vinylcarbazole) or an amine (and optionally 2,4,6-tris(trichloromethyl)-1,3,5-triazine) to initiate the cationic polymerization of epoxides and the free radical polymerization of acrylates under different irradiation sources, that is, very soft halogen lamp (approximate to 12 mW cm(-2)), laser diode at 405 nm (approximate to 1.5 mW cm(-2)) or blue LED centered at 455 nm (80 mW cm(-2)). The ANH6 based photoinitiating systems are particularly efficient for the cationic and the radical photopolymerizations, and even better than that of the well-known camphorquinone based systems. The photochemical mechanisms associated with the chemical structure/photopolymerization efficiency relationships are studied by steady state photolysis, fluorescence, cyclic voltammetry, laser flash photolysis, and electron spin resonance spin-trapping techniques. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2860-2866

  • Xiao, P.; Zhang, J.; Campolo, D.; Dumur, F.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2015, 53 (23), 2673-2684.
    Résumé : The utilization of visible lights for the fabrication of polymeric materials is recognized as a promising and environmentally friendly approach. This process relies on the photochemical generation of reactive species (e.g., radicals, radical cations, or cations) from well-designed photoinitiators (PIs) or photoinitiating systems (PISs) to initiate the polymerization reactions of different monomers (acrylates, methacrylates, epoxides, and vinyl ethers). In spite of the fact that metal complexes such as ruthenium- or iridium-based complexes have found applications in organic and polymer synthesis, the search of other low-cost metal-based complexes as PISs is emerging and attracting increasing attentions. Particularly, the concept of the photoredox catalysis has appeared recently as a unique tool for polymer synthesis upon soft conditions (use of light emitting diodes and household lamp). This highlight focuses on recently designed copper and iron complexes as


  • Xiao, P.; Zhang, J.; Dumur, F.; Tehfe, M. A.; Morlet-Savary, F.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevée, J. Progress in Polymer Science 2015, 41, 32-66.
    Résumé : Although there have been many reports on photoinitiating systems adapted to visible lights for radical photopolymerization, the challenge for the design and development of photoinitiating systems for cationic photopolymerization or concomitant radical/cationic photopolymerization (for interpenetrating polymer network IPN synthesis) with visible lights still remains open. Particularly, the recent development of cheap and easily accessible LEDs operating upon soft visible light irradiations has opened new fields for polymer synthesis. Since 2011, many novel photoinitiating systems based on organic and organometallic compounds with excellent visible light absorption have emerged and exhibited outstanding photoinitiating abilities especially for cationic photopolymerization. In this review, recent progress (mainly from 2011 to early 2014) in applications of photoinitiators and sensitive photoinitiating systems under visible lights are reported. In addition, their relative efficiencies in the photopolymerization of different monomers are exemplified and discussed.
    Mots-clés : Cationic photopolymerization, Interpenetrating polymer network IPN, Photoinitiating systems, Radical photopolymerization, Visible lights.

  • Zhang, J.; Campolo, D.; Dumur, F.; Xiao, P.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2015, 53 (1), 42-49.
    Résumé : Six iron complexes (FeCs) with various ligands have been designed and synthesized. In combination with additives (e.g., iodonium salt, N-vinylcarbazole, amine, or chloro triazine), the FeC-based systems are able to efficiently generate radicals, cations, and radical cations on a near UV or visible light-emitting diode (LED) exposure. These systems are characterized by an unprecedented reactivity, that is, for very low content 0.02% FeC-based systems is still highly efficient in photopolymerization contrary to the most famous reference systems (Bisacylphosphine oxide) illustrating the performance of the proposed catalytic approach. This work paves the way for polymerization in soft conditions (e.g., on LED irradiation). These FeC-based systems exhibit photocatalytic properties, undergo the formation of radicals, radical cations, and cations and can operate through oxidation or/and reduction cycles. The photochemical mechanisms for the formation of the initiating species are studied using steady state photolysis, cyclic voltammetry, electron spin resonance spin trapping, and laser flash photolysis techniques. (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 42-49

  • Zhang, J.; Dumur, F.; Bouzrati, M.; Xiao, P.; Dietlin, C.; Morlet-Savary, F.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2015, 53 (14), 1719-1727.
    Résumé : N,N'-dibutylquinacridone (DBQA) is utilized here for the first time as a high-performance panchromatic photoinitiator for the cationic polymerization (CP) of epoxides, the free radical polymerization (FRP) of acrylates, the thiol-ene polymerization and the synthesis of interpenetrated polymer networks (epoxide/acrylate) under violet, blue, green and yellow lights (emitted from LED at 405 nm, 470 nm, 520 nm, or 594 nm, or laser diode at 532 nm). It confers a panchromatic character to the photopolymerizable matrices. Remarkably, the proposed DBQA based photoinitiating systems exhibit quite excellent efficiency (the final monomer conversion for multifunctional monomers at room temperature can reach 62% and 50% in CP and FRP, respectively) and appear as much more powerful than the camphorquinone or Eosin-Y containing reference systems for visible light. For green light, DBQA is much more reactive than the literature reference (Eosin-Y) and for blue light, a good reactivity is found compared with camphorquinone. The photochemical mechanisms are studied by molecular orbital calculations, steady state photolysis, fluorescence, cyclic voltammetry, laser flash photolysis, and electron spin resonance spin trapping techniques. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1719-1727


  • Zhang, J.; Dumur, F.; Xiao, P.; Graff, B.; Bardelang, D.; Gigmes, D.; Fouassier, J. P.; Lalevée, J. Macromolecules 2015, 48 (7), 2054-2063.
    Résumé : Seven naphthalimide derivatives (NDP1?NDP7) with different substituents have been designed as versatile photoinitiators (PIs), and some of them when combined with an iodonium salt (and optionally N-vinylcarbazole) or an amine (and optionally chlorotriazine) are expected to exhibit an enhanced efficiency to initiate the cationic polymerization of epoxides and the free radical polymerization of acrylates under different irradiation sources (i.e., the LED at 385, 395, 405, 455, or 470 nm or the polychromatic visible light from the halogen lamp). Remarkably, some studied naphthalimide derivative based photoinitiating systems (PIS) are even more efficient than the commercial type I photoinitiator bisacylphosphine oxide and the well-known camphorquinone-based systems for cationic or radical photopolymerization. A good efficiency upon a LED projector at 405 nm used in 3D printers is also found: a 3D object can be easily created through an additive process where the final object is constructed by coating down successive layers of material. As another example of their broad potential, a NDP compound enveloped in a cyclodextrin (CD) cavity, leads to a NDP?CD complex which appears as a very efficient water-soluble photoinitiator when combined with methyldiethanol amine to form a hydrogel. The high interest of the present photoinitiator (NDP2) is its very high reactivity, allowing synthesis in water upon LED irradiation as a green way for polymer synthesis.The structure/reactivity/efficiency relationships as well as the photochemical mechanisms associated with the generation of the active species (radicals or cations) are studied by different techniques including steady state photolysis, fluorescence, cyclic voltammetry, laser flash photolysis, and electron spin resonance spin-trapping methods.

  • Zhang, J.; Sallenave, X.; Bui, T. - T.; Dumur, F.; Xiao, P.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Macromolecular Chemistry and Physics 2015, 216 (2), 218-227.
    Résumé : Two star-shaped tris(4-(thiophen-2-yl)phenyl)amine derivatives, namely tris(4-(5-(3-pentylthieno[3,2-b]thiophen-5-yl)thiophen-2-yl)phenyl) amine and tris(4-(5-(3-pentyl-2-(thiophen-2-yl)thieno[3,2-b]thiophen-5-yl) thiophen-2-yl) phenyl) amine, are developed as photoinitiators for radical and cationic polymerizations under near-UV and visible light-emitting diodes (LEDs) (e.g., 385, 405, and 455 nm). When used in combination with an iodonium salt (and optionally N-vinyl carbazole) or an amine/alkyl halide couples, they lead to excellent photoinitiating abilities for the polymerization of epoxides or (meth) acrylates under air. Compared with commercial photoinitiators, i.e., camphorquinone-based systems or bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide, the novel photoinitiators exhibit noticeably higher polymerization efficiencies under air (epoxide conversions = 41-57% vs approximate to 0%, halogen lamp exposure; methacrylate conversions = 50-55% vs 44%, LED at 405 nm exposure; methacrylate conversions = 34-42% vs 0-8%, LED at 455 nm exposure). These systems are also interesting in overcoming oxygen inhibition. The photochemical mechanisms are studied by steady-state photolysis, electron spin resonance spin trapping, fluorescence, cyclic voltammetry, and laser flash photolysis techniques.

  • Zhang, J.; Zivic, N.; Dumur, F.; Guo, C.; Li, Y.; Xiao, P.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Materials Today Communications 2015, 4, 101-108.
    Résumé : A series of diketopyrrolopyrrole derivatives (DPPs) and indigo derivatives (IDGs) are synthesized and applied as photoinitiators (PIs) for the cationic polymerization (CP) of epoxides, the free radical polymerization (FRP) of acrylates or the thiol-ene polymerization under different lights (purple, blue, green, yellow, red LEDs and green laser diode). The photochemical mechanisms involved in the presence of these PIs and additives (iodonium salt (Iod), N-vinylcarbazole (NVK), amine (MDEA) or 2,4,6-tris(trichloromethyl)-1,3,5-triazine (R-Cl)) are investigated by steady state photolysis, electron spin resonance spin trapping, fluorescence, cyclic voltammetry, and laser flash photolysis techniques. Real-time infrared spectroscopy studies reveal that DPP4/Iod/NVK is very efficient for both CP and FRP and, compared to two references (Eosin-Y and camphorquinone), displays noticeably higher polymerization efficiencies. Panchromatic curable formulations exhibiting an almost constant photosensitivity from the blue to the red are proposed. (C) 2015 Published by Elsevier Ltd.

  • Zhang, J.; Zivic, N.; Dumur, F.; Xiao, P.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Journal of Polymer Science Part a-Polymer Chemistry 2015, 53 (3), 445-451.
    Résumé : A benzophenone-naphthalimide derivative (BPND) bearing tertiary amine groups has been developed as a high-performance photoinitiator in combination with 2,4,6-tris(trichloromethyl)-1,3,5-triazine or an iodonium salt for both the free radical polymerization (FRP) of acrylates and the cationic polymerization (CP) of epoxides upon exposure to near UV and visible LEDs (385-470 nm). BPND can even produce radicals without any added hydrogen donor. The photochemical mechanisms are studied by molecular orbital calculations, steady state photolysis, electron spin resonance spin trapping, fluorescence, cyclic voltammetry and laser flash photolysis techniques. These novel BPND based photoinitiating systems exhibit an efficiency higher than that of the well-known camphorquinone-based systems (FRP and CP) or comparable to that of bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide (FRP at 455 nm). (c) 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 445-451

  • Zoller, A.; Gigmes, D.; Guillaneuf, Y. Polymer Chemistry 2015, 6 (31), 5719-5727.
    Résumé : The decomposition kinetics of the initiation reaction between benzoyl peroxide and a tertiary amine, either dimethyl-p-toluidine or dihydroxyethyl-p-toluidine, was studied by infrared spectroscopy and an Arrhenius plot was established. Based on these results, a model was developed for the polymerization of methyl methacrylate at room temperature. The model used both free volume and empirical models for propagation, termination and several side reactions. The model described the conversion for a very broad range of reaction conditions and the results were in good agreement with the experimental data. This study showed significant differences between dimethyl-p-toluidine and dihydroxyethyl-p-toluidine with respect to the gel time and the molar mass of poly(methyl methacrylate).
2014


  • Biver, E.; Berta, M.; D’Aléo, A.; Phan, T.; Maria, S.; Fages, F.; Gigmes, D.; Sentis, M.; Delaporte, P. ACS Applied Materials & Interfaces 2014, 6 (1), 41-48.
    Résumé : In this work, we investigate the effects of KrF nanosecond laser ablation on poly(methyl methacrylate) (PMMA) in combination with pyrene. Three materials containing PMMA were studied: (1) one doped with pure pyrene, (2) one doped with methyl 3-(1-pyrenyl)propanoate (so called alkylpyrene derivative thereafter), and (3) one grafted with pyrene. This last new material was developed by covalently bonding pyrene molecules to PMMA side-chains. A comparative study was undertaken to determine and compare the respective properties of the PMMA dye containing pyrene during nanosecond laser ablation at 248 nm. Cavities were etched for each material with up to 20 pulses for fluences between 0.03 and 1.7 J/cm2 in samples containing 1, 2, and 4 mol % chromophore. The threshold fluences and the effective absorption coefficients were obtained. It was observed that effective absorption coefficients increased and threshold fluences decreased with the chromophore percentages in each kind of sample. Ablation parameters were not significantly modified when the dopant was changed from pyrene to the alkylpyrene derivative. On the other hand, when pyrene molecules were grafted on the polymer, the threshold fluences decreased, whereas the effective absorption coefficients became similar at fluences above 0.6 J/cm2.

  • Delplace, V.; Harrisson, S.; Tardy, A.; Gigmes, D.; Guillaneuf, Y.; Nicolas, J. Macromolecular Rapid Communications 2014, 35 (4), 484-491.
    Résumé : Well-defined, degradable copolymers are successfully prepared by nitroxide-mediated radical ring opening polymerization (NMrROP) of oligo(ethylene glycol) methyl ether methacrylate (OEGMA) or methyl methacrylate (MMA), a small amount of acrylonitrile (AN) and cyclic ketene acetals (CKAs) of different structures. Phosphorous nuclear magnetic resonance allows in-depth chain-end characterization and gives crucial insights into the nature of the copolymer terminal sequences and the living chain fractions. By using a small library of P(OEGMA-co-AN-co-CKA) and P(MMA-co-AN-co-CKA) as macroinitiators, chain extensions with styrene are performed to furnish (amphiphilic) block copolymers comprising a degradable segment. <boxed-text content-type="graphic" position="anchor"> <graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="urn:x-wiley:10221352:media:marc201300809:marc201300809-abs-0 001">image</graphic

  • Detrembleur, C.; Jerome, C.; De Winter, J.; Gerbaux, P.; Clement, J. - L.; Guillaneuf, Y.; Gigmes, D. Polymer Chemistry 2014, 5 (2), 335-340.
    Résumé : In this communication we report the first homopolymerization of a variety of methacrylates by an NMP process at moderate temperature (40-50 degrees C), using an easily accessible and inexpensive nitroxide precursor. The combination of a low temperature azo-initiator with a hindered nitroso-compound produces a mixture of hindered nitroxides in the polymerization medium that act as efficient polymerization control agents. Results of Electron Spin Resonance (ESR) spectroscopy experiments combined with mass spectrometric studies support the proposed in situ NMP mechanism. The hindered structure of the nitroxides formed in situ is believed to be responsible for the efficiency of the process by allowing it to proceed at low temperature, therefore limiting the side reactions generally observed in NMP of methacrylates.


  • Dumur, F.; Beouch, L.; Tehfe, M. - A.; Contal, E.; Lepeltier, M.; Wantz, G.; Graff, B.; Goubard, F.; Mayer, C. R.; Lalevée, J.; Gigmes, D. Thin Solid Films 2014, 564, 351-360.
    Résumé : A series of blue fluorescent Zn (II) tetradentate Schiff base complexes has been designed and synthesized for applications in organic light-emitting diodes. The five complexes were investigated as dopant materials or as single emitters of multilayered p-i OLEDs. White OLEDs were achieved using these compounds as dopants of 4,4′,4″-tris(N-carbazolyl)triphenylamine and best devices exhibited a high quality white-light emission with remarkable CIE (Commission Internationale de l'Eclairage) coordinates (0.33, 0.34). When used as single emitters, sky-blue and blue electroluminescent devices were prepared, except with one complex that gave yellow OLEDs. Optical properties of these complexes were examined by UV–visible absorption and luminescence spectroscopy. Their electrochemical properties are also reported. These results open the route to the development of cost-effective complexes for white organic light-emitting devices applications.
    Mots-clés : Blue, Electroluminescence, Organic light emitting diodes, White, Zinc.

  • Dumur, F.; Contal, E.; Wantz, G.; Gigmes, D. European Journal of Inorganic Chemistry 2014, Nᵒ 25, 4186-4198.
    Résumé : A series of organic-metal chelate complexes of symmetric tetradentate Schiff base ligands derived from salicylaldehyde and 2-hydroxy-1-naphthaldehyde were designed and investigated. The combination of five nonconjugated flexible spacers and five conjugated rigid spacers with four salicylaldehyde derivatives provided a series of forty complexes. The series of blue to red photoluminescent complexes was investigated by UV/Vis absorption and luminescence spectroscopy in solution and in the solid state as well as cyclic voltammetry. The nature of the bridge in the ligand scaffold was determined to be the main parameter that influences the absorption and the emission color of the investigated zinc(II) complexes.


  • Dumur, F.; Lepeltier, M.; Siboni, H. Z.; Gigmes, D.; Aziz, H. Synthetic Metals 2014, 198, 131-136.
    Résumé : A series of four heteroleptic iridium (III) complexes comprising acetylacetonate as the ancillary ligand is synthesized and tested as phosphorescent dopants in OLEDs. It was found that the substitution pattern of the cyclometalated ligand strongly influences the device performance. Notably, reduced device performances were observed for the fluorinated complexes as a result of poor exciton confinement in the guest molecules.
    Mots-clés : Acetylacetonate, Electroluminescence, Iridium complex, OLED, Phosphorescence.

  • Dumur, F.; Lepeltier, M.; Siboni, H. Z.; Gigmes, D.; Aziz, H. Advanced Optical Materials 2014, 2 (3), 262-266.
    Résumé : The performance of a heteroleptic bis-cyclometalated complex based on 7,8-benzoquinoline ligands is investigated as a new emitter in phosphorescent OLEDs. The devices show very high efficiency at various dopant concentrations and maximum efficiency is achieved at 8% dopant concentration. A comparison of the performance of PHOLEDs with the new emitter versus those with Ir(ppy)3 emitter reveals an improvement of efficiency at all dopant concentrations. These preliminary results obtained with the first bzq-based emitter indicate that this family of cyclometalated proligands is a promising compound for the development of highly emissive complexes.

  • Dumur, F.; Lepeltier, M.; Siboni, H. Z.; Xiao, P.; Graff, B.; Lalevee, J.; Gigmes, D.; Aziz, H. Journal of Luminescence 2014, 151, 34-40.
    Résumé : Two heteroleptic iridium(III) complexes Ir(piq)(2)(dbm) and Ir(btp)(2)(acac) have been tested as emitters for phosphorescent OLEDs (PhOLEDs). Interestingly, device performance exhibited a marked insensitivity to the dopant concentration. In this study, a dibenzoylmethane (dbm)-based complex has also been tested for the first time as dopant for OLEDs. To evaluate the emissive properties of this new emitter belonging to a family of complexes that has not been investigated yet, identical devices were prepared with the well-known red dopant Ir(btp)(2)(acac) for comparison. The new complex Ir(piq)(2)(dbm) exhibited comparable performance to that obtained with Ir(btp)(2)(acac). (C) 2014 Elsevier B.V. All rights reserved.


  • Dumur, F.; Lepeltier, M.; Siboni, H. Z.; Xiao, P.; Graff, B.; Lalevée, J.; Gigmes, D.; Aziz, H. Thin Solid Films 2014, 562, 530-537.
    Résumé : A neutral heteroleptic iridium(III) complex bis(1-phenylisoquinoline) (dibenzoylmethane)iridium(III) Ir(piq)2(dbm) bearing a dibenzoylmethane (dbm) moiety as the ancillary ligand has been designed and investigated as an emitter in phosphorescent organic light emitting devices (PhOLEDs). To date, the family of dbm-based complexes has only been scarcely investigated in OLEDs and only one complex of this family has been tested in electroluminescent devices. Interestingly, pure red devices were obtained with this emitter. PhOLEDs were fabricated at different dopant concentrations and the best device performances were obtained in the device with 8 wt.% dopant concentration. Ir(piq)2(dbm) was characterized by UV–visible absorption and photoluminescence spectroscopy, cyclic voltammetry and theoretical calculations were also performed to support our experimental results.
    Mots-clés : Electroluminescence, Iridium complex, Organic light emitting devices, Phosphorescence, Red emission, Triplet state.


  • Dumur, F.; Lepeltier, M.; Zamani Siboni, H.; Xiao, P.; Graff, B.; Lalevée, J.; Gigmes, D.; Aziz, H. Journal of Luminescence 2014, 151, 34-40.
    Résumé : Two heteroleptic iridium(III) complexes Ir(piq)2(dbm) and Ir(btp)2(acac) have been tested as emitters for phosphorescent OLEDs (PhOLEDs). Interestingly, device performance exhibited a marked insensitivity to the dopant concentration. In this study, a dibenzoylmethane (dbm)-based complex has also been tested for the first time as dopant for OLEDs. To evaluate the emissive properties of this new emitter belonging to a family of complexes that has not been investigated yet, identical devices were prepared with the well-known red dopant Ir(btp)2(acac) for comparison. The new complex Ir(piq)2(dbm) exhibited comparable performance to that obtained with Ir(btp)2(acac).
    Mots-clés : Acetylacetone, Dibenzoylmethane, Electroluminescence, Iridium complex, OLED, Phosphorescence.


  • Dumur, F.; Lepeltier, M.; Zamani Siboni, H.; Xiao, P.; Graff, B.; Morlet-Savary, F.; Lalevée, J.; Gigmes, D.; Aziz, H. Synthetic Metals 2014, 195, 312-320.
    Résumé : Two heteroleptic iridium complexes have been designed with 1-methyl-3-propyl-5-(2,4,5-trifluorophenyl)-1H-1,2,4-triazole as the cyclometalated ligand and acetylacetone (acac) or dibenzoylmethane (dbm) as the ancillary ligands. Interestingly, when tested as emitters for phosphorescent OLEDs (PhOLEDs), these two isostructural complexes that only have varying ancillary ligands exhibited completely different behaviors in devices. Notably, highly efficient PhOLEDs were only obtained with the complex bearing dbm as the ancillary ligand. To get a deeper insight in this unexpected behavior, TD-DFT calculations were carried out. The optical properties of the two complexes (UV–vis absorption and photoluminescence) and their electrochemical behaviors were also studied.
    Mots-clés : Electroluminescence, Iridium complex, OLED, Phosphorescence, Triplet state, Yellow emission.

  • Lalevee, J.; Telitel, S.; Xiao, P.; Lepeltier, M.; Dumur, F.; Morlet-Savary, F.; Gigmes, D.; Fouassier, J. - P. Beilstein Journal of Organic Chemistry 2014, 10, 863-876.
    Résumé : In the present paper, the photoredox catalysis is presented as a unique approach in the field of photoinitiators of polymerization. The principal photocatalysts already reported as well as the typical oxidation and reduction agents used in both reductive or oxidative cycles are gathered. The chemical mechanisms associated with various systems are also given. As compared to classical iridium-based photocatalysts which are mainly active upon blue light irradiation, a new photocatalyst Ir(piq)(2)(tmd) (also known as bis(1-phenylisoquinolinato-N, C-2') iridium(2,2,6,6-tetramethyl-3,5-heptanedionate) is also proposed as an example of green light photocatalyst (toward the long wavelength irradiation). The chemical mechanisms associated with Ir(piq)(2)(tmd) are investigated by ESR spin-trapping, laser flash photolysis, steady state photolysis, cyclic voltammetry and luminescence experiments.


  • Le, D.; Casano, G.; Phan, T. N. T.; Ziarelli, F.; Ouari, O.; Aussenac, F.; Thureau, P.; Mollica, G.; Gigmes, D.; Tordo, P.; Viel, S. Macromolecules 2014, 47 (12), 3909-3916.
    Résumé : This work compares the overall sensitivity enhancements provided by dynamic nuclear polarization (DNP) for the solid-state NMR characterization of polymer samples doped with biradicals and prepared either by film casting (FC), or by glass forming (GF) using 1,1,2,2-tetrachloroethane as the solvent. Analysis of amorphous and semicrystalline polymers (polystyrene, poly(ethylene oxide), polylactide, poly(methyl methacrylate)) of varying molecular weights showed that GF provided larger sensitivity enhancements than FC but yielded DNP-enhanced 13C CPMAS spectra of lower resolution for semicrystalline polymers, owing to line-broadening due to conformational distribution of the polymer chains in frozen solution. Moreover, use of deuterated solvents significantly reduced the intensity of the solvent signals in the DNP-enhanced 13C CPMAS spectra of polymers prepared by GF, while preserving the sensitivity enhancement observed for the polymer signals. For the polymers investigated here, both FC and GF performed better than incipient wetness impregnation, yielding overall sensitivity enhancements between 5 and 40.


  • Lê, D.; Liénafa, L.; Phan, T. N. T.; Deleruyelle, D.; Bouchet, R.; Maria, S.; Bertin, D.; Gigmes, D. Macromolecules 2014, 47 (7), 2420-2429.
    Résumé : Amphiphilic block copolymers based on azido-functional polystyrene (PVBA) and hydrophilic poly(ethylene oxide) (PEO) have been synthesized by nitroxide mediated polymerization and used to prepare aqueous spherical micelles. These micelles consisting of a PEO corona and a PVBA core were stabilized by cores cross-linking under UV irradiation without addition of photoreagent. The efficiency of the core cross-linking was estimated in term of the conversion of azide groups to dibenzyldiazene junctions with liberation of gaseous nitrogen molecules. The micellar structures were studied by dynamic light scattering (DLS) and atomic force microscopy (AFM). Differential scanning calorimetry (DSC) was used to characterize the thermal behavior of freeze-dried micelles. Attachment of PEO block to a rigid core modified considerably the thermal behavior of PEO. We observed a decrease of about 15 °C for the crystallization temperature and 50% for the degree of crystallinity of cross-linked micelles submitted to 45 min UV irradiation compared to pristine copolymer.

  • Lepeltier, M.; Dumur, F.; Graff, B.; Xiao, P.; Gigmes, D.; Lalevee, J.; Mayer, C. R. Helvetica Chimica Acta 2014, 97 (7), 939-956.
    Résumé : An iridium(III) complex comprising three different cyclometalated phenylpyridine-based ligands was designed and synthesized. Interestingly, mixed-ligand complexes could be obtained by using a simple and straightforward procedure. A tris(heteroleptic) Ir-III complex was obtained as a mixture of stereoisomers that could not be separated. Photophysical properties of the tris(heteroleptic) complex was investigated by UV/VIS absorption and luminescence spectroscopy, and compared with those of the parent homoleptic complexes. Modelling by time-dependent density functional theory (TD-DFT) was also performed to elucidate the nature and the location of the excited state, and to support the experimental results.


  • Mlayah-Bellalouna, S.; Dufour, M.; Mabrouk, K.; Mejdoub, H.; Carlier, E.; Othman, H.; Belghazi, M.; Tarbe, M.; Goaillard, J. M.; Gigmes, D.; Seagar, M.; El Ayeb, M.; Debanne, D.; Srairi-Abid, N. Toxicon 2014, 92, 14-23.
    Résumé : We have purified the AaTX1 peptide from the Androctonus australis (Aa) scorpion venom, previously cloned and sequenced by Legros and collaborators in a venom gland cDNA library from Aa scorpion. AaTX1 belongs to the α-Ktx15 scorpion toxins family (αKTx15-4). Characterized members of this family share high sequence similarity and were found to block preferentially IA-type voltage-dependent K+ currents in rat cerebellum granular cells in an irreversible way. In the current work, we studied the effects of native AaTX1 (nAaTX1) using whole-cell patch-clamp recordings of IA current in substantia nigra pars compacta dopaminergic neurons. At 250 nM, AaTX1 induces 90% decrease in IA current amplitude. Its activity was found to be comparable to that of rAmmTX3 (αKTx15-3), which differs by only one conserved (R/K) amino acid in the 19th position suggesting that the difference between R19 and K19 in AaTX1 and AmmTX3, respectively, may not be critical for the toxins' effects. Molecular docking of both toxins with Kv4.3 channel is in agreement with experimental data and suggests the implication of the functional dyade K27-Y36 in toxin-channel interactions. Since AaTX1 is not highly abundant in Aa venom, it was synthesized as well as AmmTX3. Synthetic peptides, native AaTX1 and rAmmTX3 peptides showed qualitatively the same pharmacological activity. Overall, these data identify a new biologically active toxin that belongs to a family of peptides active on Kv4.3 channel.
    Mots-clés : Alpha-KTx15 toxins family, Androctonus australis scorpion, Kv4 potassium channel.

  • Mokbel, H.; Dumur, F.; Graff, B.; Mayer, C. R.; Gigmes, D.; Toufaily, J.; Hamieh, T.; Fouassier, J. - P.; Lalevee, J. Macromolecular Chemistry and Physics 2014, 215 (8), 783-790.
    Résumé : Four new push-pull dyes derived from Michler's ketones are investigated. These dyes, based on a donor--acceptor (D--A) structure, exhibit a tunable character according to the electron-withdrawing ability of the acceptor used. The new proposed structures can be used in high-performance photoinitiating systems. Remarkably, two of them are characterized by an excellent reactivity to initiate the free-radical polymerization of acrylates, the ring-opening polymerization of epoxides, as well as the synthesis of interpenetrating polymer networks (IPNs) under exposure to a laser diode at 457 nm. The chemical mechanisms are investigated by steady-state photolysis, fluorescence, and electron spin-resonance (ESR) experiments. <boxed-text content-type="graphic" position="anchor"> <graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="urn:x-wiley:10221352:media:macp201300779:macp201300779-abs-0 001">image</graphic


  • Mokbel, H.; Dumur, F.; Mayer, C. R.; Morlet-Savary, F.; Graff, B.; Gigmes, D.; Toufaily, J.; Hamieh, T.; Fouassier, J. - P.; Lalevée, J. Dyes and Pigments 2014, 105, 121-129.
    Résumé : Nine new photoinitiating systems based on a combination of new and established dyes (having an end capped polyenic structure) with an iodonium salt have been synthesized and tested for the polymerization of divinylether and epoxy monomers upon a visible light exposure. They exhibit a strong absorption in the 350–650 nm range which well matches the visible light emission of different convenient visible light sources. Interestingly, very soft irradiation conditions can be employed. Excellent polymerization profiles have been obtained from selected dye iodonium salt combinations using a halogen amp or a laser diode à 457 nm. The chemical mechanisms associated with these novel photoinitiating systems are investigated by steady-state photolysis and ESR experiments.
    Mots-clés : Cationic photopolymerization, Dyes, Halogen lamp, Laser diode, Photoinitiator, Visible light.


  • Mollica, G.; Le, D.; Ziarelli, F.; Casano, G.; Ouari, O.; Phan, T. N. T.; Aussenac, F.; Thureau, P.; Gigmes, D.; Tordo, P.; Viel, S. ACS Macro Letters 2014, 3 (9), 922-925.
    Résumé : High-field dynamic nuclear polarization (DNP) may enhance the sensitivity of solid-state NMR experiments on a wide range of systems, including synthetic polymers, owing to the transfer of electron spin polarization from radicals to nuclei upon microwave irradiation (usually at cryogenic temperatures). Provided that the radicals are homogeneously dispersed in the sample, a uniform DNP enhancement is expected for all the signals in the 13C cross-polarization magic angle spinning (CPMAS) spectrum. Here, we show that, in the case of methyl group containing polymers, a change in the cross-polarization (CP) dynamics induced by the moderate increase in sample temperature due to microwave irradiation may lead to the observation of apparent nonuniform enhancements in the DNP-enhanced 13C CPMAS spectra. This peculiar behavior should be accounted for when measuring 13C CP DNP enhancements on polymer materials, especially for heterogeneous polymer samples (for which truly nonuniform DNP enhancements could potentially be detected), or when quantitative results are sought.


  • Obadia, M. M.; Mudraboyina, B. P.; Serghei, A.; Phan, T. N. T.; Gigmes, D.; Drockenmuller, E. ACS Macro Letters 2014, 3 (7), 658-662.
    Résumé : A series of anionic poly(ionic liquid)s with 1,2,3-triazolium counter cations are prepared by cation exchange between tailormade 1,3,4-trialkylated-1,2,3-triazolium iodides and a polystyrene derivative having pendant potassium bis(trifluoromethylsulfonyl)imide groups. The physical and ion-conducting properties of the resulting materials are compared to the parent potassium-containing polyelectrolyte based on 1H NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and broadband dielectric spectroscopy (BDS) measurements. Substitution of the potassium counter cation by 1,2,3-triazolium charge carriers affords polyelectrolytes with improved processability (broader solubility and removal of the crystalline behavior) as well as a substantial increase in anhydrous ionic conductivity.


  • Pertici, V.; Trimaille, T.; Laurin, J.; Felix, M. - S.; Marqueste, T.; Pettmann, B.; Chauvin, J. - P.; Gigmes, D.; Decherchi, P. Biomaterials 2014, 35 (24), 6248-6258.
    Résumé : The present study is designed to assess the properties of a new degradable PLA-b-PHEMA block copolymer hydrogel and its therapeutic effectiveness after implantation following a thoracic spinal cord hemisection on rats. Degradable characteristics and porous aspect of the scaffold are respectively analyzed by the evaluation of its mass loss and by electron microscopy. The biomaterial toxicity is measured through in vitro tests based on motoneuron survival and neurite growth on copolymer substrate. Functional measurements are assessed by the Basso, Beattie and Bresnahan (BBB) and the Dynamic Weight Bearing (DWB) tests during 8 weeks post-surgery. Histological analyses are achieved to evaluate the presence of blood vessels and axons, the density of the glial scar, the inflammatory reaction and the myelination at the lesion site and around it. The results indicate that the synthetic PLA-b-PHEMA block copolymer is a non-toxic and degradable biomaterial that provides support for regenerating axons and seems to limit scar tissue formation. Additionally, the implantation of the porous PLA-b-PHEMA scaffold enhances locomotor improvement. The observed functional recovery highlights the potential benefits of plain tissue engineering material, which can further be optimized by bioactive molecule functionalization or transplanted cell encapsulation.
    Mots-clés : Axonal regrowth, Behavioral recovery, PLA-b-PHEMA, Spinal cord hemisection, Weight-bearing distribution.


  • Rollet, M.; Pelletier, B.; Altounian, A.; Berek, D.; Maria, S.; Beaudoin, E.; Gigmes, D. Analytical Chemistry 2014, 86 (5), 2694-2702.
    Résumé : Separation of parent homopolymers, polystyrene and poly(ethylene oxide), from the triblock copolymer polystyrene-b-poly(ethylene oxide)-b-polystyrene was investigated by means of liquid chromatography techniques. Overall suitability was evaluated and compared for size exclusion chromatography, (SEC), liquid chromatography under critical conditions of enthalpic interactions (LC CC), and liquid chromatography under limiting conditions of desorption (LC LCD). Among these techniques, LC LCD was the only one able to fully separate block copolymers from both their parent homopolymers in one single run. The efficiency of the separation was proven by 1H NMR analysis of previously collected fractions.

  • Tehfe, M. - A.; Dumur, F.; Xiao, P.; Delgove, M.; Graff, B.; Fouassier, J. - P.; Gigmes, D.; Lalevee, J. Polymer Chemistry 2014, 5 (2), 382-390.
    Résumé : Chalcone derivatives are proposed as novel photoinitiators for polymerization upon exposure to visible light (even under soft irradiation conditions: blue LED bulb at 462 nm, halogen lamp, and sunlight). Remarkably, these structures are highly versatile allowing access to photoinitiating systems for (i) the free radical polymerization of acrylates, (ii) the cationic polymerization of epoxides and vinyl ethers, (iii) the synthesis of interpenetrated polymer networks (IPNs) and (iv) the thiol-ene processes. Excellent polymerization profiles are obtained. The initiation mechanisms are analyzed through ESR, steady state photolysis, cyclic voltammetry, laser flash photolysis and fluorescence experiments.


  • Tehfe, M. - A.; Dumur, F.; Xiao, P.; Zhang, J.; Graff, B.; Morlet-Savary, F.; Gigmes, D.; Fouassier, J. - P.; Lalevée, J. Polymer 2014, 55 (10), 2285-2293.
    Résumé : Novel photoinitiators based on a phenazine scaffold are proposed for the ring opening polymerization of epoxy monomers as well as the free radical polymerization of (meth)acrylates. Good to excellent polymerization profiles can be obtained upon different easily accessible, energy saving and cheap LEDs (385, 395 and 405 nm) as well as a diode laser at 405 nm or halogen lamp opening new fields for polymer synthesis upon soft and convenient irradiations. These compounds can be particularly attractive as high performance photoinitiators in the 350–425 nm range. The initiation mechanisms are investigated in detail through fluorescence, cyclic voltammetry, steady state photolysis and electron spin resonance (ESR) experiments.
    Mots-clés : LEDs, Phenazine, Photoinitiators.

  • Tehfe, M. - A.; Schweizer, S.; Chany, A. - C.; Ysacco, C.; Clement, J. - L.; Gigmes, D.; Morlet-Savary, F.; Fouassier, J. - P.; Neuburger, M.; Tschamber, T.; Blanchard, N.; Lalevee, J. Chemistry-a European Journal 2014, 20 (17), 5054-5063.
    Résumé : The synthesis and physical characterization of a new class of N-heterocycle-boryl radicals is presented, based on five membered ring ligands with a N(sp(2)) complexation site. These pyrazole-boranes and pyrazaboles exhibit a low bond dissociation energy (BDE; BH) and accordingly excellent hydrogen transfer properties. Most importantly, a high modulation of the BDE(BH) by the fine tuning of the N-heterocyclic ligand was obtained in this series and could be correlated with the spin density on the boron atom of the corresponding radical. The reactivity of the latter for small molecule chemistry has been studied through the determination of several reaction rate constants corresponding to addition to alkenes and alkynes, addition to O-2, oxidation by iodonium salts and halogen abstraction from alkyl halides. Two selected applications of N-heterocycle-boryl radicals are also proposed herein, for radical polymerization and for radical dehalogenation reactions.

  • Telitel, S.; Telitel, S.; Bosson, J.; Spangenberg, A.; Lalevee, J.; Morlet-Savary, F.; Clement, J. - L.; Guillaneuf, Y.; Gigmes, D.; Soppera, O. Advanced Materials Interfaces 2014, 1 (5), 1400067.


  • Telitel, S.; Dumur, F.; Kavalli, T.; Graff, B.; Morlet-Savary, F.; Gigmes, D.; Fouassier, J. - P.; Lalevée, J. RSC Advances 2014, 4 (31), 15930-15936.
    Résumé : 1,3-Bis(dicyanomethylidene)indane is presented as a new initiator for ring opening polymerization of epoxides at RT. This compound behaves as a strong acid (AH) with an associated basic form (A−) that does not inhibit the propagation of the cationic polymerization. Remarkably, A− is characterized by a strong visible light absorption and can also photosensitize iodonium salt decomposition. A new iodonium salt based on A− as a counter-anion is proposed. This latter compound exhibits unusual properties: (i) excellent absorption in the 300–700 nm wavelength range and (ii) a free radical initiating ability for λ > 300 nm. The chemical mechanisms are investigated by ESR, fluorescence and steady state photolysis experiments.


  • Telitel, S.; Dumur, F.; Telitel, S.; Soppera, O.; Lepeltier, M.; Guillaneuf, Y.; Poly, J.; Morlet-Savary, F.; Fioux, P.; Fouassier, J. - P.; Gigmes, D.; Lalevée, J. Polymer Chemistry 2014, 6 (4), 613-624.
    Résumé : A new iridium complex (nIr) was designed and investigated as a photoinitiator catalyst for radical and cationic polymerizations upon very soft irradiations (lights ranging from 457 to 532 nm). A ring-opening polymerization (ROP) of an epoxy monomer was easily promoted through the interaction between nIr and an iodonium salt (Iod) upon light. The addition of N-vinylcarbazole (NVK) enhances the performance. In radical polymerization, nIr can be efficient in combination with phenacyl bromide (PBr) and optionally an amine: these photoinitiating systems work according to an original oxidative cycle and a regeneration of nIr is observed. A control of the methyl methacrylate polymerization (conducted under a 462 nm light) with 1.2–1.6 polydispersity indexes was displayed. Surface modifications by direct laser write was also easily carried out for the first time through surface re-initiation experiments, i.e. the dormant species being reactivated by light in the presence of nIr; the polymer surfaces were analyzed by XPS. The chemical mechanisms were examined through laser flash photolysis, NMR, ESR and size exclusion chromatography experiments.

  • Trimaille, T.; Autissier, L.; Rakotonirina, M. D.; Guillaneuf, Y.; Villard, C.; Bertin, D.; Gigmes, D.; Mabrouk, K. Chemical Communications 2014, 50 (21), 2744-2747.
    Résumé : Intermolecular radical 1,2-addition (IRA) of N-tert-butyl-N-(1-diethylphosphono-2,2-dimethylpropyl)aminoxyl (SG1) based alkoxyamines onto activated olefins is used as a tool for peptide ligation. This strategy relies on simple peptide pre-derivatization to obtain (i) a SG1 nitroxide functionalized resin peptide at its N-terminus (SG1-peptide alkoxyamine), (ii) a vinyl functionalized peptide (either at its C-terminus or N-terminus), and does not require any coupling agents.


  • Versace, D. - L.; Bourgon, J.; Leroy, E.; Dumur, F.; Gigmes, D.; Fouassier, J. P.; Lalevée, J. Polymer Chemistry 2014, 5 (22), 6569-6576.
    Résumé : [N,N′-Bis(salicylidene)-1,2-phenylenediamine]zinc(II) (ZnC) exhibits unexpected properties as a photoinitiator or additive for both free-radical photopolymerization reactions and in situ formation of Zn-based fillers under light activation and aerated conditions. The ZnC/2,2-dimethoxy-2-phenylacetophenone (DMPA) and ZnC/N-methyldiethanolamine (MDEA) couples are characterized by remarkable properties: (i) a photoinitiating efficiency for the radical polymerization of an acrylate matrix under air higher than that of a reference Type I photoinitiator such as DMPA (final conversion of 30–45% vs. 15%) and therefore a good ability to overcome the oxygen inhibition effect and (ii) a never reported in situ formation of Zn-based fillers (100 μm thick sticks) or composites. The photochemical properties of the ZnC are investigated by fluorescence and UV-visible spectroscopy and Electron Spin Resonance (ESR). The photodecomposition of ZnC under air is governed by either an addition of peroxyl radicals onto ZnC when associated with DMPA, or a H-abstraction mechanism when combined with MDEA. When using a ZnC/MDEA/silver salt photoinitiating system, a highly efficient polymerization of the acrylate matrix under air and a concomitant in situ production of Ag(0) NPs are observed.


  • Xiao, P.; Dumur, F.; Frigoli, M.; Graff, B.; Morlet-Savary, F.; Wantz, G.; Bock, H.; Fouassier, J. P.; Gigmes, D.; Lalevée, J. European Polymer Journal 2014, 53, 215-222.
    Résumé : The perylene derivatives (PTCTE, BPTI and DPPDI) combined with an iodonium salt or an amine (and optionally an additive) are used as photoinitiating systems to initiate the cationic polymerization (CP) of epoxides, the free radical polymerization (FRP) of acrylates, or the thiol-ene polymerization (TEP) of a Trithiol/divinylether mixture under different irradiation sources i.e. very soft halogen lamp or laser diodes at 473 nm or 457 nm (blue light). Upon a blue light exposure, the PTCTE based systems are very efficient for CP and FRP and better than the camphorquinone (CQ) based reference systems. Interestingly, the combination of PTCTE with previously studied green light and red light sensitive perylene derivatives and an iodonium salt ensures the manufacture of a panchromatic thiol-ene polymerizable film (400–650 nm) usable under various household LED bulbs irradiations (i.e. blue, green, yellow or red lights). The photochemical mechanisms are studied by steady state photolysis, fluorescence, cyclic voltammetry, laser flash photolysis and electron spin resonance spin-trapping techniques.
    Mots-clés : Blue light, Cationic photopolymerization, Perylene derivative, Photoinitiator, Radical photopolymerization, Thiol-ene photopolymerization.


  • Xiao, P.; Dumur, F.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevée, J. Macromolecules 2014, 47 (2), 601-608.
    Résumé : Novel naphthalimide derivatives (or naphthalic anhydride derivatives) have been prepared and combined with an iodonium salt, N-vinylcarbazole, amines or 2,4,6-tris(trichloromethyl)-1,3,5-triazine to produce radicals and cations upon exposure to low intensity blue lights (e.g., a household blue LED bulb). The photochemical mechanisms are studied by electron spin resonance spin trapping, fluorescence, cyclic voltammetry, laser flash photolysis, and steady state photolysis techniques. The naphthalimide derivatives (ND4) or the naphthalic anhydride derivative (ND10) based photoinitiating systems are particularly efficient for cationic, radical and thiol?ene photopolymerizations; the synthesis of interpenetrated polymer networks IPNs can also be easily carried out. Compared to camphorquinone/amine or camphorquinone/iodonium salt, the new proposed combinations appear as highly versatile and high performance visible light photoinitiating systems. Some of these photoinitiating systems can also be used for UV LED irradiations (e.g., 365, 385, or 395 nm).


  • Xiao, P.; Dumur, F.; Graff, B.; Morlet-Savary, F.; Gigmes, D.; Fouassier, J. P.; Lalevée, J. Macromolecules 2014, 47 (3), 973-978.
    Résumé : Novel naphthalene derivatives have been designed to be used as versatile photoinitiators upon a laser diode (405 nm), a polychromatic halogen lamp, or an UV LED (385 nm) exposure. The reactive species produced from photoinitiating systems based on one particular naphthalene derivative (NA3) and an iodonium salt, N-vinylcarbazole, an amine or 2,4,6-tris(trichloromethyl)-1,3,5-triazine were particularly efficient for cationic, radical, IPN and thiol?ene photopolymerizations upon low light intensity exposure. The best proposed systems exhibit a higher efficiency than references systems for visible lights (i.e., camphorquinone CQ-based photoinitiating systems). The mechanisms for the photochemical generation of reactive species (i.e., radicals and cations) were studied by electron spin resonance spin-trapping, fluorescence, cyclic voltammetry, laser flash photolysis, and steady state photolysis techniques.


  • Xiao, P.; Dumur, F.; Graff, B.; Morlet-Savary, F.; Vidal, L.; Gigmes, D.; Fouassier, J. P.; Lalevée, J. Macromolecules 2014, 47 (1), 26-34.
    Résumé : Newly synthesized indanedione derivatives combined with an iodonium salt, N-vinylcarbazole, amine, phenacyl bromide, or 2,4,6-tris(trichloromethyl)-1,3,5-triazine have been used as photoinitiating systems upon very low visible light intensities: blue lights (e.g., household blue LED bulb at 462 nm) or even a halogen lamp exposure. One of them (ID2) is particularly efficient for cationic, radical and thiol?ene photopolymerizations as well as for the synthesis of interpenetrated polymer networks (IPNs). It can be useful to overcome the oxygen inhibition. ID2 based photoinitiating systems can also be selected for the reduction of Ag+ and the in situ formation of Ag(0) nanoparticles in the synthesized polymers. The (photo)chemical mechanisms are studied by electron spin resonance spin trapping, fluorescence, cyclic voltammetry, laser flash photolysis, and steady state photolysis techniques.


  • Xiao, P.; Dumur, F.; Zhang, J.; Fouassier, J. P.; Gigmes, D.; Lalevée, J. Macromolecules 2014, 47 (12), 3837-3844.
    Résumé : Three copper complexes (E1, G1, and G2) with different ligands in combination with an iodonium salt (and optionally another additive) were used to generate radicals upon soft visible light exposure (e.g., polychromatic visible light from a halogen lamp, laser diodes at 405 and 457 nm, LEDs at 405 and 455 nm). This approach can be worthwhile and versatile to initiate free radical photopolymerization, ring-opening cationic photopolymerization, and the synthesis of interpenetrating polymer networks. The photochemical mechanisms for the production of initiating radicals are studied using cyclic voltammetry, electron spin resonance spin trapping, steady state photolysis, and laser flash photolysis techniques. The photoinitiation ability of the copper complexes based photoinitiating systems are evaluated using real-time Fourier transform infrared spectroscopy. G1 and G2 are better than the well-known camphorquinone (CQ)-based systems (i.e., TMPTA conversion = 18%, 35%, 48%, and 39% with CQ/iodonium salt, CQ/amine, G1/iodonium salt, and G2/iodonium salt, respectively; halogen lamp exposure). Interestingly, some of these systems are also better than the well-known type I phosphine oxide photoinitiator (BAPO) clearly showing their high performance. These copper complexes can be used as highly efficient catalysts in photoredox catalysis.


  • Xiao, P.; Dumur, F.; Zhang, J.; Gigmes, D.; Fouassier, J. P.; Lalevée, J. Polymer Chemistry 2014, 5 (21), 6350-6357.
    Résumé : Twenty-three copper complexes (CuC) containing different ligands were synthesized. Most of them exhibited light absorption in the visible range (adapted to LEDs, laser diodes and halogen lamp exposure). The CuC/iodonium salt (Iod), CuC/Iod/N-vinylcarbazole, CuC/alkyl bromide/methyl diethanolamine photoinitiating systems (PISs) allow good monomer conversion profiles for the free radical polymerization of trimethylolpropane triacrylate. Some of them are better than bisacylphosphine oxide or camphorquinone based systems used as references. Real-Time Fourier Transform Infrared spectroscopy and steady state photolysis were used as analytical methods. The results revealed that the ligands of the copper complexes played an important role towards the photoinitiation ability of these PISs. The use of CuC as photocatalysts to initiate thiol–ene reaction is also discussed.


  • Xiao, P.; Frigoli, M.; Dumur, F.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevée, J. Macromolecules 2014, 47 (1), 106-112.
    Résumé : Two push?pull dyes (a julolidine derivative DCJTB and a fluorenone-co-amino phenyl derivative h-B3FL), incorporated in multicomponent photoinitiating systems have been investigated for the cationic polymerization of epoxides or the radical polymerization of acrylates under visible light irradiations (household halogen lamp or green laser diode at 532 nm). The DCJTB/iodonium salt (and optionally N-vinylcarbazole) based systems are pretty efficient for the cationic polymerization of epoxides. Both dyes, when combining with an amine and 2,4,6-tris(trichloromethyl)-1,3,5-triazine, exhibit a good efficiency in the radical polymerization of acrylates. The photochemical mechanisms are studied by steady state photolysis, fluorescence, cyclic voltammetry, laser flash photolysis, and electron spin resonance spin trapping techniques.


  • Xiao, P.; Hong, W.; Li, Y.; Dumur, F.; Graff, B.; Fouassier, J. P.; Gigmes, D.; Lalevée, J. Polymer 2014, 55 (3), 746-751.
    Résumé : Several diketopyrrolopyrrole derivative based dyes (DPP), combined with an iodonium salt or an amine (and optionally an additive), are studied as photoinitiating systems for the cationic polymerization CP of epoxides or the free radical polymerization FRP of acrylates under different irradiation sources i.e. a very soft halogen lamp as well as laser diodes at 473 nm (blue light) and 532 nm (green light). The diketopyrrolopyrrole-furan derivative (FuDPP) is very efficient in CP. The structure/reactivity/efficiency relationships in this series of DPP derivatives are investigated. A comparison with a well known reference for visible light photoinitiating system (i.e. camphorquinone based photoinitiating system) is also provided showing the better efficiency of the new proposed structures. The photochemical mechanisms are studied by steady state photolysis, fluorescence, cyclic voltammetry, laser flash photolysis and electron spin resonance spin-trapping techniques.
    Mots-clés : Diketopyrrolopyrrole derivative, Photoinitiator, Visible light.


  • Xiao, P.; Hong, W.; Li, Y.; Dumur, F.; Graff, B.; Fouassier, J. P.; Gigmes, D.; Lalevée, J. Polymer Chemistry 2014, 5 (7), 2293-2300.
    Résumé : The monomeric (DPPDT) and polymeric (PDQT) diketopyrrolopyrrole–thiophene derivatives combined with an iodonium salt or an amine (and optionally an additive) are used as photoinitiating systems to initiate the cationic polymerization of epoxides or divinyl ethers, radical polymerization of acrylates and thiol–ene polymerization under different irradiation sources (i.e. very soft halogen lamp, laser diodes at 473 nm, 532 nm and 808 nm). The DPPDT based systems are very efficient upon the green light exposure. Remarkably, these systems are characterized by a higher efficiency than references based on camphorquinone, a well known photosensitizer for visible light. The photochemical mechanisms are studied by steady state photolysis, fluorescence, cyclic voltammetry, laser flash photolysis and electron spin resonance spin trapping techniques.


  • Zhang, J.; Frigoli, M.; Dumur, F.; Xiao, P.; Ronchi, L.; Graff, B.; Morlet-Savary, F.; Fouassier, J. P.; Gigmes, D.; Lalevée, J. Macromolecules 2014, 47 (9), 2811-2819.
    Résumé : Three novel photoinitiators, namely (2,2?-bithiophen-5-yl)(4-(N,N?-dimethylaminophenyl)ketone, 5,10-dimethoxybenzo[j]fluoranthene and 6,6?-(((1E,1?E)-(2,5-bis(octyloxy)-1,4-phenylene)bis(ethene-2,1-diyl))bis(4,1-phenylene))bis(1,3,5-triazine-2,4-diamine) applicable to different near UV or visible LEDs (385 nm, 395 nm, 405 nm or cold white LED) have been developed. When incorporated into multicomponent photoinitiating systems PISs (in the presence of iodonium salt (and optionally N-vinyl carbazole) or amine/alkyl halide couples), they exhibit quite excellent photoinitiating abilities for the cationic polymerization CP of epoxides or the free radical polymerization FRP of methacrylates under air. Compared to the corresponding camphorquinone-based systems, the newly developed photoinitiating systems display noticeably higher polymerization efficiencies under air (epoxide conversions = 31?55% vs ?0%, halogen lamp exposure; methacrylate conversion = 56?66% vs 0?8%, LED irradiation). These systems are very interesting to overcome the oxygen inhibition. The photochemical mechanisms have been studied by steady state photolysis, electron spin resonance spin trapping, fluorescence, cyclic voltammetry, and laser flash photolysis techniques.


  • Zhang, J.; Zivic, N.; Dumur, F.; Xiao, P.; Graff, B.; Fouassier, J. P.; Gigmes, D.; Lalevée, J. Polymer 2014, 55 (26), 6641-6648.
    Résumé : Two naphthalimide derivatives (DMAENs) containing tertiary amine groups have been designed and synthesized. Upon exposure to near UV and visible LEDs (365 nm–455 nm), they lead to radicals without adding a hydrogen donor and, in combination with 2,4,6-tris(trichloromethyl)-1,3,5-triazine, an iodonium salt or N-vinylcarbazole, they produce radicals and cations. Compared to the well-known camphorquinone or bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide photoinitiator, the novel DMAENs containing photoinitiating systems are characterized by a very high reactivity for both the free radical polymerization of acrylates and the cationic polymerization of epoxides. This outstanding performance paves the way for polymerization in soft conditions (e.g. upon LED irradiation). The photochemical mechanisms are studied by Molecular Orbitals MO calculations, steady state photolysis, fluorescence, cyclic voltammetry, electron spin resonance spin trapping and laser flash photolysis techniques.
    Mots-clés : Naphthalimide derivatives, Near UV and visible LEDs, Photoinitiator.
2013


  • Astolfi, P.; Charles, L.; Gigmes, D.; Greci, L.; Rizzoli, C.; Sorana, F.; Stipa, P. Organic & Biomolecular Chemistry 2013, 11 (8), 1399-1406.
    Résumé : The formation of a di-tert-alkyl nitroxide has been observed by Electron Spin Resonance during the exposure of coenzyme CoQ10, in both the oxidized and reduced forms, to nitrogen dioxide (˙NO2) or to nitric oxide (˙NO) in the presence of oxygen. The same kind of nitroxide has been observed also with CoQ1, CoQ3 or with 1-phenyl-3-methyl-2-butene, chosen as model compounds. In all cases, the formation of the nitroxide may be justified only by admitting the involvement of the isoprenic chain of the coenzymes and in particular the addition of ˙NO2 to the double bond. A mechanism which accounts for the formation of the nitroxide as well as the other compounds observed in the reactions is proposed and confirmed by a spectroscopic investigation (FT-IR, 1H NMR, X-ray analysis) and by ESI-MS.


  • Astolfi, P.; Greci, L.; Stipa, P.; Rizzoli, C.; Ysacco, C.; Rollet, M.; Autissier, L.; Tardy, A.; Guillaneuf, Y.; Gigmes, D. Polymer Chemistry 2013, 4 (13), 3694-3704.
    Résumé : Indolinic nitroxides derived from 2,2-diphenyl-3-phenylimino-2,3-dihydroindol-1-yloxyl (DPAIO) nitroxide were designed to improve the bulk polymerization of methacrylate derivatives. The corresponding alkoxyamines were prepared by reacting alkyl halide and nitroxide in the presence of tin hydride and PbO2. The replacement of one phenyl ring at the C-2 position on the nitroxide by either a neopentyl or an isopropyl group led to compounds with faster decomposition kinetics and better selectivity for the C–ON bond homolysis. The alkoxyamines derived from these two nitroxides were used to control the polymerization of methyl methacrylate and were also tested for the polymerization of styrene as a model for mono-substituted monomers. The shift of the molar mass distribution during the NMP of styrene showed for the first time that pure homopolymerization of styrene and methacrylate derivatives could be controlled by the same nitroxide, thus opening the way to a universal nitroxide for NMP.


  • Bélékian, D.; Cassagnau, P.; Flat, J. - J.; Quinebeche, S.; Autissier, L.; Bertin, D.; Siri, D.; Gigmes, D.; Guillaneuf, Y.; Chaumont, P.; Beyou, E. Polymer Chemistry 2013, 4 (9), 2676-2679.
    Résumé : A new H-abstracting agent, N-acetoxy-phthalimide (NAPI), was designed that cleaves mainly homolytically into acyloxyl and aminyl radicals at 190 °C. Melt PE grafting experiments confirmed the H-abstraction efficiency of NAPI. It was also shown that the grafting of maleic anhydride increased and at the same time undesired crosslinking lowered compared to peroxides.


  • Berta, M.; Biver, É.; Maria, S.; Phan, T. N. T.; D’Aleo, A.; Delaporte, P.; Fages, F.; Gigmes, D. Applied Surface Science 2013, 282, 880-886.
    Résumé : In this work we discuss the response to laser ablation of a poly(4-vinylbenzyl azide-random-methyl methacrylate) (p((S-N3)-r-MMA)) random copolymer. This material is cross-linkable thermally and upon exposure to UV light, and on cross-linked films the irradiation with a 248 nm ns KrF laser induces the formation of laser induced periodical surface structure (LIPSS). The LIPSS morphology is dependent on the amount of 4-vinylbenzyl azide (S-N3) groups in the pristine copolymer. We propose a crosslinking mechanism based on the scission of azide with formation of azo groups and we discuss the possible relationship between this chemical modifications and the formation of ripples on the bottom of laser ablation cavities.
    Mots-clés : Azo, Isomerism, LIPSS, Ripples, Unpolarized laser.

  • Bouchet, R.; Maria, S.; Meziane, R.; Aboulaich, A.; Lienafa, L.; Bonnet, J. - P.; Phan, T. N. T.; Bertin, D.; Gigmes, D.; Devaux, D.; Denoyel, R.; Armand, M. Nature Materials 2013, 12 (5), 452-457.
    Résumé : Electrochemical energy storage is one of the main societal challenges of this century. The performances of classical lithium-ion technology based on liquid electrolytes have made great advances in the past two decades, but the intrinsic instability of liquid electrolytes results in safety issues. Solid polymer electrolytes would be a perfect solution to those safety issues, miniaturization and enhancement of energy density. However, as in liquids, the fraction of charge carried by lithium ions is small (<20%), limiting the power performances. Solid polymer electrolytes operate at 80 degrees C, resulting in poor mechanical properties and a limited electrochemical stability window. Here we describe a multifunctional single-ion polymer electrolyte based on polyanionic block copolymers comprising polystyrene segments. It overcomes most of the above limitations, with a lithium-ion transport number close to unity, excellent mechanical properties and an electrochemical stability window spanning 5V versus Li+/Li. A prototype battery using this polyelectrolyte outperforms a conventional battery based on a polymer electrolyte.

  • Bremond, P.; Butscher, T.; Roubaud, V.; Siri, D.; Viel, S. Journal of Organic Chemistry 2013, 78 (20), 10524-10529.
    Résumé : The C-ON bond homolysis in alkoxyamines can be influenced by the presence of an intramolecular hydrogen bond (IHB) between the alkyl and the nitroxyl fragments, which leads to an 8-fold decrease in the homolysis rate constant k(d). When the IHB is disrupted by the solvent or by substitution of the hydrogen involved in the IHB by a protecting group (OMe, OAc, OBz, OBn, or OTBDMS), a higher homolysis rate constant k(d) is observed, as expected from the correlations developed by Marque (Bet-tin, D.; Gigmes, D.; Marque, S.; Tordo, P. Macromolecules 2005, 38, 2638-2650). Results were confirmed by DFT calculations at the B3LYP/6-31G(d,p) level.


  • Delplace, V.; Tardy, A.; Harrisson, S.; Mura, S.; Gigmes, D.; Guillaneuf, Y.; Nicolas, J. Biomacromolecules 2013, 14 (10), 3769-3779.
    Résumé : Three cyclic ketene acetals, 2-methylene-1,3-dioxepane (MDO), 5,6-benzo-2-methylene-1,3-dioxepane (BMDO), and 2-methylene-4-phenyl-1,3-dioxolane (MPDL), have been copolymerized with oligo(ethylene glycol) methyl ether methacrylate and a small amount of acrylonitrile (or styrene) at 90 °C by nitroxidemediated radical ring-opening polymerization, as a convenient way to prepare degradable PEG-based copolymers for biomedical applications. MPDL was the best candidate, enabling high monomer conversions to be reached and well-defined PEG-based copolymers with adjustable amount of ester groups in the main chain to be synthesized, leading to nearly complete hydrolytic degradation (5% KOH aqueous solution, ambient temperature). The noncytotoxicity of the obtained copolymers was shown on three different cell lines (i.e., fibroblasts, endothelial cells and macrophages), representing a promising approach for the design of degradable precursors for PEGylation and bioconjugation via the NMP technique.

  • Detrembleur, C.; Clement, J. - L.; Sciannamea, V.; Jerome, C.; Catala, J. - M.; Gigmes, D.; Autissier, L.; Botek, E.; Zarycz, N.; Champagne, B. Journal of Polymer Science Part a-Polymer Chemistry 2013, 51 (8), 1786-1795.
    Résumé : The styrene polymerization initiated by benzoyl peroxide (BPO) in the presence of N-tert-butyl--isopropylnitrone as nitroxide precursor is well-controlled provided that a prereaction between the nitrone and BPO is carried out in suitable conditions prior to polymerization at a higher temperature. Electron spin resonance (ESR) spectroscopy was implemented to probe the nitroxides formed during both steps, that is, the prereaction and polymerization, and to get crucial information regarding the structure of the nitroxides responsible for the polymerization control. ESR studies combined with first principles calculations have evidenced that nitroxides observed during the prereaction in the presence of styrene and during the polymerization steps consist of a mixture of two macronitroxides. One is formed by the addition of a growing polystyrene chain to the nitrone as would be expected. However, the second one results from the addition of a polystyrene chain to tert-butyl nitroso that is in situ formed presumably by decomposition of the first macronitroxide type. (c) 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013, 51, 1786-1795


  • Dommanget, C.; Boisson, C.; Charleux, B.; D’Agosto, F.; Monteil, V.; Boisson, F.; Junkers, T.; Barner-Kowollik, C.; Guillaneuf, Y.; Gigmes, D. Macromolecules 2013, 46 (1), 29-36.
    Résumé : Enhanced spin capturing polymerization (ESCP)?a recent and versatile technique in the field of controlled radical polymerization?achieves control over molecular weights and the synthesis of complex copolymer structures for a wide range of monomers. In the present work, the use of ESCP was extended to the radical polymerization of ethylene under mild conditions (low temperature and medium ethylene pressure) using a nitrone as spin trapping agent. It was demonstrated that the evolution of polyethylene (PE) molecular weight can be accurately described by classical ESCP kinetic equations. A PE bearing a midchain alkoxyamine function was thus obtained with high selectivity (90%). A more complex structure was produced from the radical polymerization of ethylene in the presence of a midchain alkoxyamine-functionalized polystyrene (PS) synthesized by ESCP in the form of ABA triblock copolymer (where A is polystyrene and B polyethylene).

  • Dumur, F.; Contal, E.; Wantz, G.; Phan, T. N. T.; Bertin, D.; Gigmes, D. Chemistry-a European Journal 2013, 19 (4), 1373-1384.
    Résumé : A series of styrene-substituted 1,3,4-oxadiazoles has been designed and investigated as new low-molecular-weight organogelators. The photophysical properties of the resulting thermoreversible organogels have been characterized by UV/Vis absorption and luminescence spectroscopies. Surprisingly, the gelation ability of the oxadiazoles depended on the presence of the styrene moiety as gelation of the investigated oxadiazoles did not take place in its absence. Gel formation was accompanied by a modification of the fluorescence of the organogelators in the supramolecular state. UV irradiation of the gels caused a rearrangement of the immobilized 1,3,4-oxadiazoles bearing a styrene moiety by a tandem [4+2] and [3+2] cascade reaction. Structure modification and color change of the gels were also evident upon irradiation.


  • Dumur, F.; Lepeltier, M.; Graff, B.; Contal, E.; Wantz, G.; Lalevée, J.; Mayer, C. R.; Bertin, D.; Gigmes, D. Synthetic Metals 2013, 182, 13-21.
    Résumé : Two neutral heteroleptic iridium(III) complexes bearing substituted pyridine 1,2,4-triazoles as the ancillary ligands have been designed and investigated as emitters for PhOLEDs. Interestingly, blue and blue–green devices were obtained with the two complexes. Best devices were obtained with C1 and reached a maximum brightness of 10,200 cd/m2, a current efficiency of 4.3 cd/A at an operation voltage of 7.9 V while exhibiting the unusual low turn-on voltage of only 2.8 V. UV–visible absorption and photoluminescence spectroscopy as well as the cyclic voltammetry of the two iridium(III) complexes were also investigated.
    Mots-clés : Blue emission, Electroluminescence, Iridium complex, OLED, Phosphorescence, Triazole, Triplet state.


  • Dumur, F.; Yuskevitch, Y.; Wantz, G.; Mayer, C. R.; Bertin, D.; Gigmes, D. Synthetic Metals 2013, 177, 100-104.
    Résumé : The optical and electronic properties of a solution-processed light-emitting electrochemical cell (LEC) based on an anionic iridium (III) complex as the emitter material has been designed and investigated. The obtained multi-layered devices emitted light of a light-green color (CIE, x = 0.29, y = 0.45) at low external applied voltage. The electroluminescent devices fabricated from this anionic iridium complex exhibited a relatively moderate electroluminescent efficiency and a luminance as high as 140 cd/m2 at 7.2 V.
    Mots-clés : Anion, Electroluminescence, Iridium complex, LEC, Phosphorescence, PVK, Triplet state.

  • Edeleva, M.; Marque, S. R. A.; Kabytaev, K.; Guillaneuf, Y.; Gigmes, D.; Bagryanskaya, E. Journal of Polymer Science Part a-Polymer Chemistry 2013, 51 (6), 1323-1336.
    Résumé : Thermal decomposition of four tertiary N-(2-methylpropyl)-N-(1-diethylphosphono-2,2-dimethylpropyl)-N-oxyl (SG1)-based alkoxyamines (SG1-C(Me)2-C(O)-OR, R = Me, tBu, Et, H) has been studied at different experimental conditions using 1H and 31P NMR spectroscopies. This experiment represents the initiating step of methyl methacrylate polymerization. It has been shown that H-transfer reaction occurs during the decomposition of three alkoxyamines in highly degassed solution, whereas no products of H-transfer are detected during decomposition of SG1-MAMA alkoxyamine. The value of the rate constant of H-transfer for alkoxyamines 1 (SG1-C(Me)2-C(O)-OMe) and 2 (SG1-C(Me)2-C(O)-OtBu) has been estimated as 1.7 x 103 M1s1. The high influence of oxygen on decomposition mechanism is found. In particular, in poorly degassed solutions, nearly quantitative formation of oxidation product has been observed, whereas at residual pressure of 105 mbar, the main products originate from H-atom transfer reaction. The acidity of the reaction medium affects the decomposition mechanism suppressing the H-atom transfer. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013


  • Faury, T.; Dumur, F.; Clair, S.; Abel, M.; Porte, L.; Gigmes, D. CrystEngComm 2013, 15 (11), 2067-2075.
    Résumé : A series of substituted 1,4-benzenediboronic acids (BDBA) was synthesized and their thermal properties investigated. Two diboronic acids were studied as building-blocks for covalent organic framework (COF) formation, namely 2,5-dimethoxy-1,4-benzenediboronic acid and 2-nitro-1,4-benzeneboronic acid. Interestingly, substitution of the BDBA core caused a dramatic decrease of the polymerization temperature leading to the formation of a less organized structure.


  • Handké, N.; Ficheux, D.; Rollet, M.; Delair, T.; Mabrouk, K.; Bertin, D.; Gigmes, D.; Verrier, B.; Trimaille, T. Colloids and Surfaces B: Biointerfaces 2013, 103, 298-303.
    Résumé : Efficient biomolecule conjugation to the surface of biodegradable colloidal carriers is crucial for their targeting efficiency in drug/vaccine delivery applications. We here propose a potent strategy to drastically improve peptide immobilization on biodegradable polylactide (PLA) nanoparticles (NPs). Our approach particularly relies on the use of an amphiphilic block copolymer PLA-b-poly(N-acryloxysuccinimide-co-N-vinylpyrrolidone) (PLA-b-P(NAS-co-NVP)) as NP surface modifier, whose the N-succinimidyl (NS) ester functions of the NAS units along the polymer chain ensure N-terminal amine peptide coupling. The well-known immunostimulatory peptide sequence derived from the human interleukin 1β (IL-1β), VQGEESNDK, was coupled on the NPs of 169 nm mean diameter in phosphate buffer (pH 8, 10 mM). A maximum amount of 2 mg immobilized per gram of NPs (i.e. 0.042 peptide nm−2) was obtained. Introduction of a three lysine tag at the peptide N-terminus (KKKVQGEESNDK) resulted in a dramatic improvement of the immobilized peptide amounts (27.5 mg/g NP, i.e. 0.417 peptide nm−2). As a comparison, the density of tagged peptide achievable on surfactant free PLA NPs of similar size (140 nm), through classical EDC or EDC/NHS activation of the surface PLA carboxylic end-groups, was found to be 6 mg/g NP (i.e. 0.075 peptide nm−2), showing the decisive impact of the P(NAS-co-NVP)-based hairy corona for high peptide coupling. These results demonstrate that combined use of lysine tag and PLA-b-P(NAS-co-NVP) surfactant represents a valuable platform to tune and optimize surface bio-functionalization of PLA-based biodegradable carriers.
    Mots-clés : Amphiphilic block copolymer, N-succinimidyl ester, Peptide conjugation, Polylactide nanoparticles.

  • Handke, N.; Lahaye, V.; Bertin, D.; Delair, T.; Verrier, B.; Gigmes, D.; Trimaille, T. Macromolecular Bioscience 2013, 13 (9), 1213-1220.
    Résumé : Glycopolymer-corona-based micelles are obtained in a one-pot procedure, through reaction of D-mannosamine or D-glucosamine with the N-succinimidyl (NS) esters of a poly(D,L-lactide)-block-poly(N-acryloxysuccinimide-co-N-vinylpyrrolidone ) (PLA-b-P(NAS-co-NVP)) amphiphilic copolymer (presenting quasi-alternating NAS/NVP units) in dimethyl sulfoxide (DMSO), followed by nanoprecipitation and dialysis against water. The glycopolymer micelles exhibit a higher CMC and size than those obtained from unmodified copolymer, due to increased hydrophilicity of the external block as a result of sugar derivatization, and the availability of the sugars at the micelle surface is evidenced through interactions with Concanavalin A (Con A) lectin, as attested by turbidimetric measurements and enzyme-linked lectin assay (ELLA). Interestingly, the glycopolymer micelles can be further used for hydrophobic molecule encapsulation and release, as shown with imiquimod, while keeping their interactions with con A intact. It is concluded that the PLA-based amphiphilic/reactive copolymer represents a versatile platform for glycopolymer-based micelle constructs for drug/vaccine delivery.

  • Lalevee, J.; Tehfe, M. - A.; Dumur, F.; Gigmes, D.; Graff, B.; Morlet-Savary, F.; Fouassier, J. - P. Macromolecular Rapid Communications 2013, 34 (3), 239-245.
    Résumé : Two new photoinitiators with unprecedented light absorption properties are proposed on the basis of a suitable truxene skeleton where several


  • Lefay, C.; Guillaneuf, Y.; Moreira, G.; Thevarajah, J. J.; Castignolles, P.; Ziarelli, F.; Bloch, E.; Major, M.; Charles, L.; Gaborieau, M.; Bertin, D.; Gigmes, D. Polymer Chemistry 2013, 4 (2), 322-328.
    Résumé : Chitosan (CS) was modified by SG1-based nitroxide-mediated polymerization under heterogeneous conditions. After introduction of acrylamide and/or acrylate functions onto the CS backbone followed by intermolecular 1,2 radical addition of the BlocBuilder alkoxyamine (CS–BB), methyl methacrylate (MMA) in the presence of a small amount of acrylonitrile (AN) or sodium 4-styrenesulfonate (SS) was polymerized by nitroxide-mediated polymerization (NMP). ESR and free-solution capillary electrophoresis confirmed the synthesis of CS–BB. The successful synthesis of CS-g-P(MMA-co-AN) and CS-g-PSS grafted copolymers was proved by TGA and solid-state NMR spectroscopy with ca. 20 to 30 wt% of grafted synthetic polymer in the final product.


  • Lepeltier, M.; Dumur, F.; Marrot, J.; Contal, E.; Bertin, D.; Gigmes, D.; Mayer, C. R. Dalton Transactions 2013, 42 (13), 4479-4486.
    Résumé : The first reported combination of regioselective hydro-defluorination and a ligand exchange reaction during the syntheses of neutral iridium(III) complexes is presented. Surprisingly, loss of one fluorine atom per ligand combined with a complete ligand exchange reaction on the transition metal were jointly observed during a bridge-splitting and substitution reaction of two different dimeric iridium(III) precursor complexes with two different ancillary ligands. The regioselectivity of defluorination was evidenced in both cases. The reaction time was identified as a factor strongly impacting the kinetics of the thermally induced reaction.


  • Lepeltier, M.; Dumur, F.; Wantz, G.; Vila, N.; Mbomekallé, I.; Bertin, D.; Gigmes, D.; Mayer, C. R. Journal of Luminescence 2013, 143, 145-149.
    Résumé : Highly efficient red-emitting Phosphorescent Organic Light-Emitting Diodes (PhOLEDs) based on a neutral vacuum-sublimatable heteroleptic iridium (III) complex have been designed and studied. Heteroleptic complex Ir(piq)2(acac) was prepared in one step with acetylacetone (acac) as the ancillary ligand. Electronic and spectroscopic properties of Ir(piq)2(acac) were investigated by UV–visible absorption, fluorescence spectroscopy and cyclic voltammetry. Electrophosphorescent devices comprising Ir(piq)2(acac) as dopant of TCTA exhibited outstanding electroluminescence performance with a current efficiency of 10.0 cd A−1, a maximum power efficiency of 7.2 lm W−1 and a maximal brightness of 3540 cd m−2 was reached at 8.0 V. CIE coordinates close to the standard red of the national television system committee were obtained (0.67, 0.33).
    Mots-clés : Electroluminescence, Iridium, OLED, Phosphorescence, Red.


  • Lessard, B. H.; Guillaneuf, Y.; Mathew, M.; Liang, K.; Clement, J. - L.; Gigmes, D.; Hutchinson, R. A.; Marić, M. Macromolecules 2013, 46 (3), 805-813.
    Résumé : Previously, nitroxide-mediated controlled copolymerization (NMP) of methyl methacrylate (MMA) using BlocBuilder unimolecular initiator was found to require much less controlling comonomer when using 9-(4-vinylbenzyl)-9H-carbazole (VBK) compared to styrene (S) as a comonomer (minimum ?1 mol % VBK versus 4.4 mol % S). Here, we explored why this was the case. Initially, the use of dimethylformamide (DMF) solvent in the copolymerization of MMA/S was studied as the MMA/VBK copolymerizations were done in DMF. The results confirmed that the increased effectiveness of VBK as a controlling comonomer was not due to the solvent or other experimental conditions. Second, the propagation rate constant kP,VBK and various ?kP?MMA/VBK for MMA/VBK copolymerizations were determined using pulsed laser polymerization?size exclusion chromatography (PLP-SEC), and the dissociation rate constants kd,VBK for the VBK-BlocBuilder adduct and PVBK chains were determined using electron paramagnetic resonance (EPR) spectroscopy, showing that kd for VBK was very similar to S and ?kP?MMA/VBK was very similar to kP,MMA. Finally, modeling of the system using PREDICI was done and illustrated that the difference in reactivity ratios between MMA/S and MMA/VBK was ultimately one of the major reasons for the increased control of VBK versus S. This study showed that propagation rate of the copolymerization and equilibrium constant for the dormant/active species are not the only parameters that govern controlled NMP, and the effect of reactivity ratios between the methacrylate and the controlling comonomer must also be considered for the controlled nitroxide-mediated copolymerization of methacrylate-rich mixtures.

  • Maniego, A. R.; Ang, D.; Guillaneuf, Y.; Lefay, C.; Gigmes, D.; Aldrich-Wright, J. R.; Gaborieau, M.; Castignolles, P. Analytical and Bioanalytical Chemistry 2013, 405 (28), 9009-9020.
    Résumé : Branching was detected in polyacrylates synthesised through radical polymerization via solution-state NMR, while inconsistencies have been reported for the determination of the molar mass of hydrophilic polyacrylates using aqueous-phase and organic-phase size-exclusion chromatography. In this work, poly(sodium acrylate)s, PNaAs, of various topologies were separated for the first time using free-solution capillary electrophoresis (CE). Free-solution CE does not separate the PNaAs by their molar mass, similarly to separations by liquid chromatography in the critical conditions, rather by different topologies (linear, star branched, and hyperbranched). The electrophoretic mobility of PNaAs increases as the degree of branching decreases. Separation is shown to be not only by the topology but also by the end groups as expected for a separation in the critical conditions: replacing a relatively bulky nitroxide end group with hydrogen atom yielded a higher electrophoretic mobility. This novel method, capillary electrophoresis in the critical conditions enabled, for the first time, the separation of hydrophilic polyacrylates according to their topology (branching) and their chain ends. This will allow meaningful and accurate characterization of their branched topologies as well as molar masses and progress in for advanced applications such as drug delivery or flocculation.

  • Mokbel, H.; Dumur, F.; Telitel, S.; Vidal, L.; Xiao, P.; Versace, D. - L.; Tehfe, M. - A.; Morlet-Savary, F.; Graff, B.; Fouassier, J. - P.; Gigmes, D.; Toufaily, J.; Hamieh, T.; Lalevee, J. Polymer Chemistry 2013, 4 (23), 5679-5687.
    Résumé : Novel push pull dyes containing a (substituted) hydrocarbon moiety and a malonate (or a malononitrile) moiety are proposed as photoinitiators for the ring opening polymerization of epoxides as well as the synthesis of interpenetrated polymer networks (IPNs) upon exposure to visible light (laser diode, halogen lamp, etc.). Excellent polymerization profiles are obtained. The role of the acceptor and donor moieties in these dyes towards their light absorption properties, the associated photochemical processes and their photoinitiating ability is investigated. A very efficient dye has been selected for the reduction of Ag+ and the in situ formation of Ag(0) nanoparticles in the synthesized IPNs.


  • Mondal, S.; Dumur, F.; Barbarat, B.; Grauby, O.; Gigmes, D.; Olive, D.; Bertrand, M. P.; Nechab, M. Colloids and Surfaces B: Biointerfaces 2013, 112, 513-520.
    Résumé : Two novel enediynes containing an aromatic ring and substituted by two thiol functions as end-groups were designed and studied as functionalizing agent of gold nanoparticles. Phototriggered cyclization of the capping agent under UV–visible irradiation was investigated. Interestingly, the length of the thiol-substituted chain was shown to influence significantly the cyclization rate. Depending on the length of the spacer, either polymerization or simple cyclization of the coating agent was evidenced. The present study underscores the possibility of finely controlling the fate of the coating agent (polymerization/cyclization). Nanocomposites were characterized by UV–visible absorption spectroscopy, dynamic light scattering (DLS) technique and transmission electron microscopy (TEM) measurements. Finally, the ability of the colloidal solutions to induce photoinitiated damages to PcDNA3 supercoiled DNA was evaluated. Interestingly, an increase as high as 50% of the DNA cleavage could be registered when adding enediynes-capped gold nanoparticles to solutions of enediynes. In particular, the enhancement of DNA scission was observed in both thermal and photochemical activation modes.
    Mots-clés : Cyclization, DNA, Enediyne, Gold nanoparticles, Photochemistry.

  • Moreira, G.; Charles, L.; Major, M.; Vacandio, F.; Guillaneuf, Y.; Lefay, C.; Gigmes, D. Beilstein Journal of Organic Chemistry 2013, 9, 1589-1600.
    Résumé : The range of applications of cellulose, a glucose-based polysaccharide, is limited by its inherently poor mechanical properties. The grafting of synthetic polymer chains by, for example, a "grafting from" process may provide the means to broaden the range of applications. The nitroxide-mediated polymerization (NMP) method is a technique of choice to control the length, the composition and the architecture of the grafted copolymers. Nevertheless, cellulose is difficult to solubilize in organic media because of inter and intramolecular hydrogen bonds. One possibility to circumvent this limitation is to solubilize cellulose in N,N-dimethyl-formamide (DMF) or N,N-dimethylacetamide (DMA) with 5 to 10 wt % of lithium salts (LiCl or LiBr), and carry out grafted polymerization in this medium. The stability of nitroxides such as SG1 has not been studied under these conditions yet, even though these parameters are of crucial importance to perform the graft modification of polysaccharide by NMP. The aim of this work is to offer a model study of the stability of the SG1 nitroxide in organic media in the presence of unprotected glucose or cellobiose (used as a model of cellulose) and in the presence of lithium salts (LiBr or LiCl) in DMF or DMA. Contrary to TEMPO, SG1 proved to be stable in the presence of unprotected sugar, even with an excess of 100 molar equivalents of glucose. On the other hand, lithium salts in DMF or DMA clearly degrade SG1 nitroxide as proven by electron-spin resonance measurements. The instability of SG1 in these lithium-containing solvents may be explained by the acidification of the medium by the hydrolysis of DMA in the presence of LiCl. This, in turn, enables the disproportionation of the SG1 nitroxide into an unstable hydroxylamine and an oxoammonium ion. Once the conditions to perform an SG1-based nitroxide-mediated graft polymerization from cellobiose have been established, the next stage of this work will be the modification of cellulose and cellulose derivatives by NMP.

  • Nicolas, J.; Guillaneuf, Y.; Lefay, C.; Bertin, D.; Gigmes, D.; Charleux, B. Progress in Polymer Science 2013, 38 (1), 63-235.
    Résumé : Nitroxide-mediated polymerization (NMP) is a controlled/living radical polymerization (CLRP) technique that enables the design of well-defined, functional and complex macromolecular architectures. This comprehensive review covers all aspects, features and achievements of NMP, from its discovery to 2012. All topics related to NMP are thoroughly discussed and detailed in-depth: synthetic approaches to nitroxides and alkoxyamines, kinetic aspects and polymerization features, range of controllable monomers, polymer characterization, polymerization processes (ionic liquids, dispersed media, etc.), macromolecular coupling approaches, functionalization strategies, macromolecular architectures, bio-related and hybrid materials, industrial applications as well as environmental constraints. (C) 2012 Elsevier Ltd. All rights reserved.


  • Ouari, O.; Phan, T.; Ziarelli, F.; Casano, G.; Aussenac, F.; Thureau, P.; Gigmes, D.; Tordo, P.; Viel, S. ACS Macro Letters 2013, 2 (8), 715-719.
    Résumé : Dynamic nuclear polarization (DNP) is shown to greatly improve the solid-state nuclear magnetic resonance (SSNMR) analysis of synthetic polymers by allowing structural assignment of intrinsically diluted NMR signals, which are typically not detected in conventional SSNMR. Specifically, SSNMR and DNP SSNMR were comparatively used to study functional polymers for which precise structural elucidation of chain ends is essential to control their reactivity and to eventually obtain advanced polymeric materials of complex architecture. Results show that the polymer chain-end signals, while hardly observable in conventional SSNMR, could be clearly identified in the DNP SSNMR spectrum owing to the increase in sensitivity afforded by the DNP setup (a factor ?10 was achieved here), hence providing access to detailed structural characterization within realistic experimental times. This sizable gain in sensitivity opens new avenues for the characterization of ?smart? functional polymeric materials and new analytical perspectives in polymer science.

  • Ould-Yahoui, A.; Sbai, O.; Baranger, K.; Bernard, A.; Gueye, Y.; Charrat, E.; Clement, B.; Gigmes, D.; Dive, V.; Girard, S. D.; Feron, F.; Khrestchatisky, M.; Rivera, S. Cell Transplantation 2013, 22 (6), 993-1010.
    Résumé : Adult olfactory ectomesenchymal stem cells (OE-MSCs) and olfactory ensheathing cells (OECs), both from the nasal olfactory lamina propria, display robust regenerative properties when transplanted into the nervous system, but the mechanisms supporting such therapeutic effects remain unknown. Matrix metalloproteinases (MMPs) are an important family of proteinases contributing to cell motility and axonal outgrowth across the extracellular matrix (ECM) in physiological and pathological conditions. In this study, we have characterized for the first time in nasal human OE-MSCs the expression profile of some MMPs currently associated with cell migration and invasiveness. We demonstrate different patterns of expression for MMP-1, MMP-2, MMP-9, and MT1-MMP upon cell migration when compared with nonmigrating cells. Our results establish a correspondence between the localization of these proteinases in the migration front with the ability of cells to migrate. Using various modulators of MMP activity, we also show that at least MMP-2, MMP-9, and MT1-MMP contribute to OE-MSC migration in an in vitro 3D test. Furthermore, we demonstrate under the same conditions of culture used for in vivo transplantation that OE-MSCs and OECs secrete neurotrophic factors that promote neurite outgrowth of cortical and dorsal root ganglia (DRG) neurons, as well as axo-dendritic differentiation of cortical neurons. These effects were abolished by the depletion of MMP-2 and MMP-9 from the culture conditioned media. Altogether, our results provide the first evidence that MMPs may contribute to the therapeutic features of OE-MSCs and OECs through the control of their motility and/or their neurotrophic properties. Our data provide new insight into the mechanisms of neuroregeneration and will contribute to optimization of cell therapy strategies.

  • Pertici, V.; Amendola, J.; Laurin, J.; Gigmes, D.; Madaschi, L.; Carelli, S.; Marqueste, T.; Gorio, A.; Decherchi, P. Asn Neuro 2013, 5 (2), 149-166.
    Résumé : There have been considerable interests in attempting to reverse the deficit because of an SCI (spinal cord injury) by restoring neural pathways through the lesion and by rebuilding the tissue network. In order to provide an appropriate micro-environment for regrowing axotomized neurons and proliferating and migrating cells, we have implanted a small block of pHPMA [poly N-(2-hydroxypropyl)-methacrylamide] hydrogel into the hemisected T10 rat spinal cord. Locomotor activity was evaluated once a week during 14 weeks with the BBB rating scale in an open field. At the 14th week after SCI, the reflexivity of the sub-lesional region was measured. We also monitored the ventilatory frequency during an electrically induced muscle fatigue known to elicit the muscle metaboreflex and increase the respiratory rate. Spinal cords were then collected, fixed and stained with anti-ED-1 and anti-NF-H antibodies and FluoroMyelin. We show in this study that hydrogel-implanted animals exhibit: (i) an improved locomotor BBB score, (ii) an improved breathing adjustment to electrically evoked isometric contractions and (iii) an H-reflex recovery close to control animals. Qualitative histological results put in evidence higher accumulation of ED-1 positive cells (macrophages/monocytes) at the lesion border, a large number of NF-H positive axons penetrating the applied matrix, and myelin preservation both rostrally and caudally to the lesion. Our data confirm that pHPMA hydrogel is a potent biomaterial that can be used for improving neuromuscular adaptive mechanisms and H-reflex responses after SCI.


  • Robbes, A. - S.; Cousin, F.; Meneau, F.; Dalmas, F.; Schweins, R.; Gigmes, D.; Jestin, J. Macromolecules 2013, 46 (3), 1260-1260.


  • Tardy, A.; Delplace, V.; Siri, D.; Lefay, C.; Harrisson, S.; Pereira, B. de F. A.; Charles, L.; Gigmes, D.; Nicolas, J.; Guillaneuf, Y. Polymer Chemistry 2013, 4 (17), 4776-4787.
    Résumé : The ring-opening polymerization of cyclic ketene acetals (CKAs) by controlled radical mechanisms represents an alternative route for the synthesis of aliphatic polyesters. For the first time, 5,6-benzo-2-methylene-1,3-dioxepane (BMDO) and 2-methylene-4-phenyl-1,3-dioxolane (MPDL) were homopolymerized by nitroxide mediated polymerization (NMP), from the commercially available SG1-based BlocBuilder MA alkoxyamine. Various experimental conditions (i.e., reaction temperature, nature of solvent, and nature of the alkyl initiating radical) were varied to determine the optimized conditions in terms of polymerization kinetics and living character of the final polymer. Chain-end extensions from either PS-SG1 or PBMDO-SG1 were also performed in order to furnish PS-b-PBMDO and PBMDO-b-PS, respectively, thus demonstrating the synthesis of block copolymers comprising a CKA block. In order to have a better insight into the polymerization mechanism, the occurrence of side reactions was analyzed by 31P NMR spectroscopy and ESI-MS. It was supposed that the ketal-based macroradical could be irreversibly trapped by nitroxide and thus the corresponding macroalkoxyamine decomposed by CO–N bond dissociation. DFT calculations as well as PREDICI modeling were also undertaken in order to support this hypothesis.

  • Tehfe, M. - A.; Dumur, F.; Contal, E.; Graff, B.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Macromolecular Chemistry and Physics 2013, 214 (19), 2189-2201.
    Résumé : Truxene-acridine-1,8-dione derivatives (Tr_AD) are proposed as new photoinitiators of polymerization under very soft irradiation (by a household halogen lamp), as well as laser-diode exposure at 405 nm. They exhibit a strong absorption around 380 nm. The Tr_AD/diphenyl iodonium salt/9-vinylcarbazole combination is able to promote the ring-opening polymerization of an epoxide, whereas the Tr_AD/alkyl halide/amine system is very efficient in initiating the radical photopolymerization of an acrylate. Excellent polymerization profiles are obtained. Acrylate/epoxide blends are also easily polymerized. These Tr_ADs in the three-component systems behave as photocatalysts according to oxidative cycles. The mechanisms are discussed for the different multicomponent initiating systems.


  • Tehfe, M. - A.; Dumur, F.; Contal, E.; Graff, B.; Morlet-Savary, F.; Gigmes, D.; Fouassier, J. - P.; Lalevée, J. Polymer Chemistry 2013, 4 (5), 1625-1634.
    Résumé : New aromatic derivatives PyD based on a pyrene moiety are proposed here as new photoinitiators (PIs) in multi-component systems (with an iodonium salt, a sulfonium salt and optionally a silane) for the radical polymerization of acrylates and the cationic polymerization of epoxy, epoxy-silicone and vinyl ethers. These new photoinitiators allow the use of a long wavelength excitation (using visible light delivered by a halogen lamp, a laser diode at 457 nm or a Xe–Hg lamp). Excellent polymerization profiles are obtained. For polymerization processes using pyrene, very low conversions are reached in agreement with the lack of absorption of this compound for λ > 380 nm i.e.PyDs are attractive compounds for visible light. Acrylate–epoxide, acrylate–vinyl ether and vinyl ether–epoxide blends are also easily polymerized i.e. for the synthesis of interpenetrating or crosslinked polymer networks. The initiation step mechanisms analyzed by ESR, fluorescence, steady state photolysis and laser flash photolysis experiments are discussed.


  • Tehfe, M. - A.; Dumur, F.; Graff, B.; Clément, J. - L.; Gigmes, D.; Morlet-Savary, F.; Fouassier, J. - P.; Lalevée, J. Macromolecules 2013, 46 (3), 736-746.
    Résumé : A new Type I photoinitiator Tr_DMPA is described. It consists in three 2,2?-dimethoxy 2-phenyl acetophenone (DMPA) units grafted onto a truxene (Tr) scaffold. Compared to DMPA itself, the lowest electronic transition exhibits a ππ* character and the corresponding molar extinction coefficients ε are increased from about 400 M?1 cm?1 (at about 332 nm for DMPA) to 63?000 M?1 cm?1 (at 338 nm for Tr_DMPA); such huge values are exceptional in Type I photoinitiators at this wavelength. Tr_DMPA undergoes a fast cleavage and efficiently initiate an acrylate polymerization upon a Xe?Hg lamp, a halogen lamp or a laser diode exposure at 405 nm (upon very low light intensities: 2?12 mW/cm2) in the 300?450 nm range. The polymerization of epoxides or divinylethers is also feasible in the presence of an iodonium salt at 405 nm where reference photoinitiators cannot efficiently operate. The chemical mechanisms analyzed by ESR, fluorescence, steady state photolysis, and laser flash photolysis experiments are discussed.


  • Tehfe, M. - A.; Dumur, F.; Graff, B.; Gigmes, D.; Fouassier, J. - P.; Lalevée, J. Macromolecules 2013, 46 (9), 3332-3341.
    Résumé : The actual photonitiators PI can only operate in a restricted part of the visible spectrum; as a consequence, several PIs are usually necessary to harvest all the emitted visible photons. In the present paper, new dyes based on a donor?π-acceptor structure (1,3-indanedione derivatives) are incorporated into visible light sensitive photoinitiating systems of polymerization. They exhibit an unusual and remarkable broad absorption lying from the blue to the red. When employed in the presence of an iodonium salt (Iod) and optionally N-vinylcarbazole (NVK), these dyes can efficiently initiate the radical photopolymerization of acrylates, the cationic photopolymerization of epoxide and vinylether monomers and the hybrid cure of acrylate/epoxide blends under exposure, e.g., at 405, 457, 473, 532, and 635 nm. They partly behave as organic photocatalysts. These particular light absorption properties and the initiation step mechanisms are investigated in detail.

  • Tehfe, M. - A.; Dumur, F.; Graff, B.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Macromolecular Chemistry and Physics 2013, 214 (9), 1052-1060.
    Résumé : New perylene-3,4:9,10-bis(dicarboximide) (PBI) photoinitiators/photosensitizers derived from perylene-3,4:9,10-tetracarboxylic dianhydride are synthesized and investigated for the formation of free radicals under air and under very soft irradiation (i.e., halogen lamp) or laser diode exposure at 532 nm. Such a PBI in combination with a diphenyl iodonium salt and N-vinylcarbazole or a silane very efficiently promotes the ring-opening polymerization of epoxides and can also generate acrylate/epoxide interpenetrated polymer networks. It partly behaves as a metal-free organic photocatalyst operating in an oxidative catalytic cycle. The different chemical intermediates are characterized by ESR and laser flash photolysis experiments. The mechanisms involved in the initiation step are discussed.


  • Tehfe, M. - A.; Dumur, F.; Graff, B.; Morlet-Savary, F.; Fouassier, J. - P.; Gigmes, D.; Lalevée, J. Macromolecules 2013, 46 (10), 3761-3770.
    Résumé : Among other photoinitiating systems, aromatic ketone based compounds have been largely exploited as photoinitiators (PIs). However, none of these compounds efficiently absorb above 420 nm. The search of novel architectures of PIs for getting an important red-shift of the absorption is crucial for the use of visible lights for polymer synthesis. Novel bifunctional dyes derived from the Michler?s ketone structure are proposed here as photoinitiators for the free radical polymerization of acrylates and the cationic polymerization of epoxides upon exposure to 457, 473, and 532 nm laser diodes and even to a green LED bulb at 514 nm. Excellent polymerization profiles are obtained. These original dyes exhibit a push?pull molecular character for a remarkable covering of the visible lights. The formation of the radicals and the ions in the two- and three-component photoinitiating systems is described and the initiation steps are discussed.

  • Tehfe, M. - A.; Dumur, F.; Graff, B.; Morlet-Savary, F.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Polymer Chemistry 2013, 4 (7), 2313-2324.
    Résumé : New Type I and Type II photoinitiators based on 2,2-dimethoxy-2-phenylacetophenone (DMPA), benzophenone (BP) and thioxanthone (TX) linked to a pyrene (Py) moiety (Py_DMPA, Py_BP, Py_TX) are proposed here for the free radical polymerization of acrylates and the cationic polymerization of epoxides and vinylethers under a Xe-Hg lamp, laser diode at 405 nm or a halogen lamp. Excellent polymerization profiles using Py_DMPA and Py_BP are obtained, i.e. better than those recorded with the reference compounds (DMPA and BP). Specifically, Py_DMPA and Py_BP absorb in the near UV-visible range (360-420 nm range; absorption red-shift similar to 15 nm), exhibit huge epsilon values (up to a 90 fold increase) and high photochemical reactivity. The mechanisms analyzed by electron spin resonance, steady state photolysis, fluorescence and laser flash photolysis experiments are discussed for the different initiating systems.

  • Tehfe, M. - A.; Dumur, F.; Graff, B.; Morlet-Savary, F.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Polymer Chemistry 2013, 4 (13), 3866-3875.
    Résumé : A series of new dyes based on (thio)barbituric acid derivatives were synthesized and used as photoinitiators of polymerization upon very soft irradiation (laser diodes at 457 nm and 473 nm; blue LED bulbs or even a halogen lamp). These dyes can work according to an oxidative cycle (dye/diphenyl iodonium salt/N-vinylcarbazole system) or a reductive cycle (dye/amine/alkyl halide system) and partly behave as organic photocatalysts. Ring-opening polymerization (ROP) of epoxides and radical polymerization (RP) of acrylates are easily promoted. Excellent


  • Tehfe, M. - A.; Dumur, F.; Telitel, S.; Gigmes, D.; Contal, E.; Bertin, D.; Morlet-Savary, F.; Graff, B.; Fouassier, J. - P.; Lalevée, J. European Polymer Journal 2013, 49 (5), 1040-1049.
    Résumé : Zinc-based metal complexes (ZnC) are proposed as original photoinitiators in multi-component systems for the formation of free radicals under visible light irradiation. The ZnC/iodonium salt/additive three-component systems (where the additive can be a silane or a divinyl ether) present an excellent ability to promote either the free radical polymerization of an acrylate, the cationic polymerization of a divinyl ether and the polymerization of acrylate/vinyl ether blends under very soft irradiations (e.g. halogen lamp irradiation) or laser diodes (457 or 532 nm) exposure. The mechanisms are investigated by photolysis, luminescence and ESR experiments.
    Mots-clés : Cationic photopolymerization (ROP), Divinyl ether, Free radical polymerization, Photocatalysts, Silane, Zinc complex (ZnC).

  • Tehfe, M. - A.; Dumur, F.; Vila, N.; Graff, B.; Mayer, C. R.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Macromolecular Rapid Communications 2013, 34 (13), 1104-1109.
    Résumé : For polymer synthesis upon visible light, actual photoinitiator operates in a restricted part of the spectrum. As a consequence, several photoinitiators are necessary to harvest all of the emitted visible photons. Herein, 2,7-di-tert-butyldimethyldihydropyrene is used for the first time as a multicolor photoinitiator for the cationic polymerization of epoxides. Upon addition of diphenyliodonium hexafluorophosphate and optionally N-vinylcarbazole, the originality of this approach is to allow efficient monomer conversions under various excitation light sources in the 360-650 nm wavelength range: halogen lamps, and light-emitting and laser diodes. The synthesis of an interpenetrated polymer network from an epoxide/acrylate blend using a red light at 635 nm is also feasible. The formed polymer material exhibits a photochromic character.


  • Tehfe, M. - A.; Dumur, F.; Xiao, P.; Graff, B.; Morlet-Savary, F.; Fouassier, J. - P.; Gigmes, D.; Lalevée, J. Polymer Chemistry 2013, 4 (15), 4234-4244.
    Résumé : Novel photoinitiators derived from a chromone structure are proposed for the free radical polymerization of acrylates and the free radical promoted cationic polymerization of epoxides upon exposure to a 457 nm laser diode and even under soft irradiation conditions (blue LED bulb at 462 nm and halogen lamp). Good polymerization profiles are obtained. These original dyes exhibit a push–pull molecular character as revealed by MO calculations. The initiation mechanisms are analyzed through ESR, fluorescence and laser flash photolysis experiments.

  • Tehfe, M. - A.; Mondal, S.; Nechab, M.; Dumur, F.; Bertrand, M. P.; Graff, B.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Macromolecular Chemistry and Physics 2013, 214 (12), 1302-1308.
    Résumé : New thiols for efficient thiol-ene polymerization reactions are presented. They do not exhibit any unpleasant odor, are characterized by quite good light-absorption properties at > 300 nm, and generate thiyl radicals upon UV-light exposure. Due to these interesting properties and contrary to many previously reported methodologies, the present thiol-acrylate polymerizations can be efficiently carried out without the presence of any additional photoinitiator. The chemical mechanisms are investigated by steady-state photolysis and electron spion resonance (ESR) experiments. Important parameters can also be extracted from molecular orbital calculations.


  • Tehfe, M. - A.; Zein-Fakih, A.; Lalevée, J.; Dumur, F.; Gigmes, D.; Graff, B.; Morlet-Savary, F.; Hamieh, T.; Fouassier, J. - P. European Polymer Journal 2013, 49 (2), 567-574.
    Résumé : A series of pyridinium salts were synthesized and investigated as new dyes for photoinitiating systems of polymerization. They exhibit a strong absorption at about 550 nm well matching with the visible light emission of different convenient visible light sources. Interestingly, very soft irradiation (halogen lamp) as well as laser diode exposure (457 and 532 nm) can be used. When employed in the presence of a silane and an iodonium salt, they efficiently initiate the free radical polymerization of acrylates and free radical promoted cationic polymerization of epoxides. An acrylate/epoxide blend is also easily polymerized i.e. for the synthesis of interpenetrating polymer networks. In combination with amine, the proposed dyes can also initiate free radical polymerizations. The mechanisms analyzed by ESR and photolysis experiments are discussed for the different multi-component initiating systems.
    Mots-clés : Cationic photopolymerization, Dyes, Photoinitiators, Pyridinium salt, Radical photopolymerization.


  • Telitel, S.; Dumur, F.; Gigmes, D.; Graff, B.; Fouassier, J. P.; Lalevée, J. Polymer 2013, 54 (12), 2857-2864.
    Résumé : Novel functionalized ketones (K_PY) incorporating one/two pyrene moieties or a pyridinium chromophore for radical and/or cationic polymerization under soft irradiation conditions (Xe–Hg lamp, halogen lamp) are proposed. These compounds exhibit red-shifted absorptions and enhanced molar extinction coefficients (e.g. for near visible lights (395 nm), the absorption can be increased by a factor of 20). The ability of the various K_PY/amine couple in the radical polymerization of an acrylate (up to 75% conversion) and the different K_PY/diphenyliodonium salt system in the cationic polymerization of an epoxide (up to 70% conversion) is often better than that of reference compounds. These structures are also very efficient to overcome the oxygen inhibition. Molecular orbital calculations, ESR experiments and laser flash photolysis allow an investigation of the absorption properties, the excited state processes and the involved initiation mechanisms.
    Mots-clés : Cationic photopolymerization, Photoinitiator, Radical photopolymerization.

  • Telitel, S.; Dumur, F.; Faury, T.; Graff, B.; Tehfe, M. - A.; Gigmes, D.; Fouassier, J. - P.; Lalevee, J. Beilstein Journal of Organic Chemistry 2013, 9, 877-890.
    Résumé : Eleven di- and trifunctional compounds based on a core-pyrene pi structure (Co_Py) were synthesized and investigated for the formation of free radicals. The application of two- and three-component photoinitiating systems (different Co_Pys with the addition of iodonium or sulfonium salts, alkyl halide or amine) was investigated in detail for cationic and radical photopolymerization reactions under near-UV-vis light. The proposed compounds can behave as new photocatalysts. Successful results in terms of rates of polymerization and final conversions were obtained. The strong MO coupling between the six different cores and the pyrene moiety was studied by DFT calculations. The different chemical intermediates are characterized by ESR and laser flash photolysis experiments. The mechanisms involved in the initiation step are discussed, and relationships between the core structure, the Co_Py absorption property, and the polymerization ability are tentatively proposed.


  • Tintaru, A.; Chendo, C.; Phan, T. N. T.; Rollet, M.; Giordano, L.; Viel, S.; Gigmes, D.; Charles, L. Analytical Chemistry 2013, 85 (11), 5454-5462.
    Résumé : Cleavage of the labile halide termination upon matrix-assisted laser desorption/ionization (MALDI) has always been reported as a major concern in mass analysis of polystyrene prepared by atom transfer radical polymerization (ATRP). By studying this issue using nuclear magnetic resonance (NMR) and electrospray ionization?mass spectrometry, we evidence here that the ionization step is not involved in this deleterious process. Instead, removal of the halogen was shown to readily occur upon interaction of the silver salt (AgTFA) used as the cationizing agent in mass spectrometry, either in solution or in the solid-state when performing solvent-free sample preparation. In solution, this silver-induced reaction mostly consists of a nucleophilic substitution, leading to polystyrene molecules holding different terminations, depending on relative nucleophilicity of species present in the liquid-phase solution composition. In chloroform supplemented with AgTFA, trifluoroacetate-terminated PS were evidenced in ESI-MS spectra but experienced end-group cleavage in MALDI. In contrast, the major methoxy-terminated PS macromolecules formed when the silver-catalyzed nucleophilic substitution was performed in methanol were generated as intact gas-phase ions using both ionization techniques. This controlled and fast modification could hence be advantageously used as a rapid sample pretreatment for safe MALDI mass analysis of ATRP-made polystyrene.


  • Xiao, P.; Dumur, F.; Bui, T. T.; Goubard, F.; Graff, B.; Morlet-Savary, F.; Fouassier, J. P.; Gigmes, D.; Lalevée, J. ACS Macro Letters 2013, 2 (8), 736-740.
    Résumé : The photoinitiating abilities of indoline and squaraine dyes (D102 and SQ02) incorporated in multicomponent systems for the cationic polymerization of an epoxide or a vinyl ether have been investigated. The polymerizable films exhibit a panchromatic character as revealed by their photosensitivity to a halogen lamp (370?800 nm); household LED bulbs centered at 462 nm (blue), 514 nm (green), 591 nm (yellow), and 630 nm (red); and laser diodes at 457, 473, 532, and 635 nm. SQ02 is particularly efficient in the 520?700 nm range, while D102 exhibits a good efficiency in the 400?580 nm region. The radical photopolymerization of an acrylate can also be observed particularly at 635 nm or upon a halogen lamp. The photochemical mechanisms are studied by steady state photolysis, fluorescence, cyclic voltammetry, electron spin resonance spin trapping, and laser flash photolysis techniques.


  • Xiao, P.; Dumur, F.; Frigoli, M.; Tehfe, M. - A.; Graff, B.; Fouassier, J. P.; Gigmes, D.; Lalevée, J. Polymer Chemistry 2013, 4 (21), 5440-5448.
    Résumé : The abilities of two naphthalimide derivatives with a methacryloyl group to initiate, when incorporated in multi-component systems, a ring-opening polymerization of epoxides and a radical polymerization of acrylates under different irradiation sources (e.g. very soft halogen lamp irradiation, laser diode at 457 nm, laser diode at 405 nm and blue LED bulb at 462 nm) have been investigated. One of them is particularly efficient for the cationic and radical photopolymerization of an epoxide/acrylate blend in a one-step hybrid cure and leads to the formation of an interpenetrated polymer network IPN (30 s for getting tack free coatings). The migration stability of one of these naphthalimide derivatives is found to be excellent in the cured polyacrylates and IPNs. The photochemical mechanisms are studied by steady state photolysis, fluorescence, cyclic voltammetry, electron spin resonance spin trapping and laser flash photolysis techniques.


  • Xiao, P.; Dumur, F.; Graff, B.; Fouassier, J. P.; Gigmes, D.; Lalevée, J. Macromolecules 2013, 46 (17), 6744-6750.
    Résumé : Anthraquinone derivatives in combination with an iodonium salt (and optionally N-vinylcarbazole) have been used as photoinitiating systems. One of them (Oil Blue N) that is particularly efficient for cationic, IPN, and thiol?ene polymerization upon red lights (laser diode at 635 nm or household red LED bulb at 630 nm) belongs to the very few systems available at this long wavelength in such experimental conditions (low light intensity in the 10?100 mW/cm2 range). Their abilities to initiate the cationic photopolymerization of epoxides or vinyl ethers under very soft halogen lamp irradiation have been also investigated. The photochemical mechanisms are studied by steady state photolysis, fluorescence, cyclic voltammetry, and electron spin resonance spin trapping techniques.

  • Xiao, P.; Dumur, F.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Jacques, L. Macromolecular Rapid Communications 2013, 34 (18), 1452-1458.
    Résumé : Nine different perylene derivatives are prepared and their ability to initiate, when combined with an iodonium salt (and optionally N-vinylcarbazole), a ring-opening cationic photopolymerization of epoxides under very soft halogen lamp irradiation is investigated. One of them is particularly efficient under a red laser diode exposure at 635 nm and belongs now to the very few systems available at this wavelength. The photochemical mechanisms are studied by steady-state photolysis, electron spin resonance spin trapping, fluorescence, cyclic voltammetry, and laser flash photolysis techniques.


  • Xiao, P.; Dumur, F.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevée, J. Macromolecules 2013, 46 (19), 7661-7667.
    Résumé : Newly developed benzophenone derivatives in combination with an iodonium salt (and optionally N-vinylcarbazole) or amines have been used as photoinitiating systems. Their abilities to initiate cationic photopolymerization of epoxides and/or radical photopolymerization of acrylates under very soft visible halogen lamp, LED and laser diodes irradiations have been investigated. One of them (BPD5) is particularly efficient for the cationic and radical photopolymerization of an epoxide/acrylate blend in a one-step hybrid cure and leads to the formation of an interpenetrated polymer network IPN upon the house hold blue LED bulb exposure (1 min for getting tack free coatings). The performances attained with some derivatives are better than those obtained with camphorquinone, used as reference photoinitiator, highlighting their high initiating abilities. These systems can be useful to overcome the oxygen inhibition for very low light intensity. The photochemical mechanisms are studied by molecular orbital calculations, fluorescence, cyclic voltammetry, laser flash photolysis, electron spin resonance spin trapping, and steady state photolysis techniques.

  • Xiao, P.; Dumur, F.; Tehfe, M. - A.; Graff, B.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Macromolecular Chemistry and Physics 2013, 214 (15), 1749-1755.
    Résumé : New photoinitiating systems based on a polyoxometalate (POM) are proposed: phosphomolybdic acid in combination with silane, germane, or iodonium salt can be used to generate silyl, germyl, or phenyl radicals as well as silylium cations. The photochemical mechanisms are studied by steady-state photolysis and electron spin resonance. The phosphomolybdic acid/silane/iodonium salt system can initiate either the radical photopolymerization of acrylates or the cationic photopolymerization of epoxides. The synthesis of interpenetrated polymer networks can also be carried out. The mechanical properties of the synthesized polymers are affected by the presence of POM in the matrix, as shown by their dynamic mechanical analysis (DMA).

  • Xiao, P.; Dumur, F.; Tehfe, M. - A.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevee, J. Macromolecular Chemistry and Physics 2013, 214 (20), 2276-2282.
    Résumé : Ten acridinediones (ADs) with different substituents are prepared and investigated for their abilities to initiate a ring-opening cationic photopolymerization in combination with an iodonium salt and N-vinylcarbazole upon UV-vis light (Xe-Hg lamp; >330 nm) or visible light (halogen lamp) exposure. The structural effects in the ADs are outlined. The cationic and radical photopolymerization of an epoxide/acrylate blend in a one-step hybrid cure very efficiently leads to the formation of an interpenetrated polymer network under UV-vis light or visible light irradiation (30 s for tack-free coatings). The photochemical mechanisms are studied by molecular orbital calculations, steady-state photolysis, electron spin resonance-spin trapping, cyclic voltammetry, fluorescence, and laser flash photolysis techniques. [GRAPHICS] .


  • Xiao, P.; Dumur, F.; Tehfe, M. - A.; Graff, B.; Gigmes, D.; Fouassier, J. P.; Lalevée, J. Polymer 2013, 54 (14), 3458-3466.
    Résumé : Seven difunctional acridinediones DAD were prepared and investigated for their abilities to initiate a ring-opening cationic photopolymerization in combination with an iodonium salt (and optionally N-vinylcarbazole) upon UV/visible light (Xe–Hg lamp; &gt;330 nm) or visible light (halogen lamp) exposure. The structural effects in the DADs and the role of the radical cation are outlined. The cationic and radical photopolymerization of an epoxide/acrylate blend in a one-step hybrid cure leads to the formation of an interpenetrated polymer network. The photochemical mechanisms are studied by fluorescence, steady state photolysis, cyclic voltammetry, electron spin resonance spin trapping, and laser flash photolysis techniques.
    Mots-clés : Acridinedione derivatives, Photoinitiators, Ring-opening polymerization (ROP).


  • Xiao, P.; Dumur, F.; Thirion, D.; Fagour, S.; Vacher, A.; Sallenave, X.; Morlet-Savary, F.; Graff, B.; Fouassier, J. P.; Gigmes, D.; Lalevée, J. Macromolecules 2013, 46 (17), 6786-6793.
    Résumé : Thiophene and polythiophene derivatives have been prepared and used as photoinitiators upon visible light exposure. Their abilities to initiate, when combined with an iodonium salt (and optionally N-vinylcarbazole), a ring-opening cationic photopolymerization of epoxides and radical photopolymerization of acrylates under various different irradiation sources (i.e., very soft halogen lamp irradiation, laser diode at 405, 457, 473, 532, and 635 nm and blue LED bulb at 462 nm) have been investigated. These systems are characterized by a remarkable performance for purple to red light exposure. They are also particularly efficient for the cationic and radical photopolymerization of an epoxide/acrylate blend in a one-step hybrid cure and lead to the formation of an interpenetrated polymer network IPN (30 s for getting tack-free coatings). Their migration stability is excellent in the cured IPNs. The photochemical mechanisms are studied by steady state photolysis, fluorescence, cyclic voltammetry, electron spin resonance spin trapping, and laser flash photolysis techniques.

  • Xiao, P.; Simonnet-Jegat, C.; Dumur, F.; Schrodj, G.; Tehfe, M. - A.; Fouassier, J. P.; Gigmes, D.; Lalevee, J. Polymer Chemistry 2013, 4 (16), 4526-4530.
    Résumé : alpha-Silicon polyoxomolybdates in combination with an iodonium salt and/or a silane are used to generate phenyl and/or silyl radicals as well as silylium cations upon UV light irradiation. These species can initiate the radical photopolymerization of acrylates, the cationic photopolymerization of epoxides and the photopolymerization of epoxy/acrylate blends (i.e. for the synthesis of interpenetrated polymer networks) thereby leading to the formation of polyoxometalate/polymer hybrid materials. The mechanical properties of e.g. the polyether films are affected by the presence of polyoxometalate in the matrix as shown by their dynamic mechanical analysis (DMA). The photochemical mechanisms are studied by steady state photolysis, cyclic voltammetry, and electron spin resonance techniques.
2012

  • Barrere, C.; Chendo, C.; Phan, T. N. T.; Monnier, V.; Trimaille, T.; Humbel, S.; Viel, S.; Gigmes, D.; Charles, L. Chemistry-a European Journal 2012, 18 (25), 7916-7924.
    Résumé : A sample pretreatment was evaluated to enable the production of intact cationic species of synthetic polymers holding a labile end-group using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. More specifically, polymers obtained by nitroxide-mediated polymerization involving the MAMA-SG1 alkoxyamine were stirred for a few hours in trifluoroacetic acid (TFA) to induce the substitution of a tert-butyl group on the nitrogen of nitroxide end-group by a hydrogen atom. Nuclear magnetic resonance, electrospray ionization tandem mass spectrometry, and theoretical calculations were combined to scrutinize this sample pretreatment from both mechanistic and energetic points of view. The substitution reaction was found to increase the dissociation energy of the fragile C?ON bond to a sufficient extent to prevent this bond to be spontaneously cleaved during MALDI analysis. This TFA treatment is shown to be very efficient regardless of the nature of the polymer, as evidenced by reliable MALDI mass spectrometric data obtained for poly(ethylene oxide), polystyrene and poly(butylacrylate).

  • Dumur, F.; Bertin, D.; Gigmes, D. International Journal of Nanotechnology 2012, 9 (3-7), 377-395.
    Résumé : Light-emitting Electrochemical Cells (LECs) constitute one of the most recent generations of Organic Light-Emitting Diodes (OLEDs). The main difference between LECs and OLEDs is that LECs include mobile ions in the active layer. Ionic transition-metal complexes and especially ionic iridium (III) complexes have recently attracted widespread attention as potential electroluminescent materials for LECs. Herein, we present an overview of LECs incorporating ionic iridium (III) complexes as phosphorescent emitters. Synthetic strategies developed to introduce iridium (III) complexes in the active layer are also reviewed. Despite the numerous intrinsic drawbacks still remaining, recent advances make iridium-based LECs promising devices for future commercial and scientific applications.


  • Faury, T.; Clair, S.; Abel, M.; Dumur, F.; Gigmes, D.; Porte, L. The Journal of Physical Chemistry C 2012, 116 (7), 4819-4823.
    Résumé : We report on formation of a new surface covalent organic framework (SCOF) based on a sequential polymerization in two stages. The bifunctional precursor used, p-bromo-benzene boronic acid (BBBA), was vapor deposited in ultra-high-vacuum conditions on a Au(111) surface. In a first step the boronic acid moieties reacted to form trimers linked by covalent boroxine rings. In a second step, an Ullmann coupling reaction was thermally activated to form C?C bonds between the trimers, leading to the final polymeric network. By this procedure the growth mechanism was optimized and the polymerization reaction yield could approach 100%. A well-extended network was obtained, differing from the ideal honeycomb-like network by a substantial number of nonhexagonal pores, which are intrinsic defects to the polymer structure. A comparison of the two competing reactions provides new insights into the complex mechanisms governing growth of two-dimensional covalent networks.


  • Guillaneuf, Y.; Gigmes, D.; Junkers, T. Macromolecules 2012, 45 (13), 5371-5378.
    Résumé : The impact of formation of midchain radicals?and more specifically the follow up reactions of ?-scission and macromonomer addition to propagating macroradicals stemming from this process?on the nitroxide-mediated polymerization of acrylates have been studied via kinetic modeling with the software package Predici on the example of butyl acrylate polymerization at 120 °C. Only small influences of the midchain radical formation on the livingness of the process is observed, however, large effects must be envisaged by the (reverse) scission reaction at high monomer-to-polymer conversions. A significant loss of livingness, depending on the temperature, monomer and initiator concentration must be expected at elevated stages of polymerizations. For a polymerization at 120 °C and a target chain length of 100, less than 75% livingness of the polymer product can be expected at 80% conversion. From this point of polymerization on, significant broadening of the overall polymer product is predicted in accordance to literature data and eventually the chain-length?conversion relation is lost at the end of reaction.

  • Guillaneuf, Y.; Lamps, J. - P.; Catala, J. - M.; Gigmes, D.; Drockenmuller, E. Journal of Polymer Science Part a-Polymer Chemistry 2012, 50 (18), 3750-3757.
    Résumé : A new dialkylated a-hydrogenated linear nitroxide and the corresponding 1-phenylethyl alkoxyamine were synthesized in two and three steps, respectively. The alkoxyamine was involved in the polymerization of styrene at 60 degrees C, and the in situ concentration of nitroxide was monitored by electron spin resonance spectroscopy. The enhanced characteristics of these new alkylated alkoxyamine and nitroxide (k?d60 = 1.5 x 10-4 s-1 and k?c60 = 5.7 x 104 L mol-1 s-1) yielded a monomer consumption one order of magnitude higher than styrene thermal polymerization. This resulted in well-defined polystyrenes up to 70,000 g mol-1 and the observation of a control occurring through the establishment of the radical persistent effect, that is, ln([M]0/[M]) = t2/3. Experimentally determined kinetic constants were involved in PREDICI modelings to investigate the influence of temperature and initial alkoxyamine concentration on the kinetics as well as on the livingness and the controlled character of the polymerization. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012


  • Hurtgen, M.; Debuigne, A.; Gigmes, D.; Jérôme, C.; Detrembleur, C. Polymer 2012, 53 (20), 4353-4358.
    Résumé : The grafting mechanism of poly(vinyl acetate) macroradicals prepared by cobalt-mediated radical polymerization onto C60 is investigated. The experimental conditions directly impact the nature and stability of the PVAc/C60 adducts. In the presence of residual initiating radicals that can compete with PVAc° macroradicals for addition onto C60, mixtures of PVAc/C60 adducts having between one and eight polymer chains per C60 are formed. PVAc/C60 adducts prepared with low [PVAc]:[C60] ratios may contain weak C60–C60 bonds that further dissociate and account for the instability of the products. The formation of such dimers can be lessened by increasing the temperature from 30 °C to 100 °C. The temperature increase also allows a complete dissociation of the PVAc-Co dormant species into PVAc° macroradicals and an almost quantitative grafting of eight PVAc chains onto C60, leading to well-defined C60(PVAc)8 octa-adducts. These results might shed new light on the grafting onto C60 of macroradicals prepared by other CRP techniques.
    Mots-clés : Controlled radical polymerization, Fullerenes, Star polymers.


  • Lalevée, J.; Dumur, F.; Mayer, C. R.; Gigmes, D.; Nasr, G.; Tehfe, M. - A.; Telitel, S.; Morlet-Savary, F.; Graff, B.; Fouassier, J. P. Macromolecules 2012, 45 (10), 4134-4141.
    Résumé : The photoredox catalysis approach is used to initiate the free radical promoted cationic photopolymerization of N-vinylcarbazole (NVK) under very soft irradiation conditions (halogen lamp, blue or green LED bulbs) using visible-light harvesting photocatalysts (mainly Ir(III) complexes) in iodonium salt and silane containing photoinitiating systems. The reactions were shown to proceed via an oxidative catalytic cycle where the generated free radicals are oxidized into cations. The effect of NVK on this catalytic cycle is discussed. Epoxy/NVK matrixes can also be polymerized. The luminescent properties of the synthesized polymers are presented.


  • Lalevée, J.; Dumur, F.; Tehfe, M. - A.; Zein-Fakih, A.; Gigmes, D.; Morlet-Savary, F.; Graff, B.; Fouassier, J. - P. Polymer 2012, 53 (22), 4947-4954.
    Résumé : New dyes (based on diamine, oligophenylenevinylene, salphen ligands and polyazine skeletons) are checked here for the formation of free radicals under very soft irradiation conditions (halogen lamp, blue or green LED bulbs and laser diode at 457 nm) under air. Three component systems involving a combination of diamine (or oligophenylenevinylene) dye/diphenyl iodonium salt/silane (or N-vinylcarbazole NVK) are used. Excellent ring-opening polymerization ROP profiles are obtained. A comparison of the ability of these dyes vs. Eosin-Y (used as a well known reference dye) is also provided. The chemical mechanisms are investigated in detail by ESR and luminescence experiments. Upon a visible light exposure, these systems generate aryl, silyl or αN radicals that can be easily oxidized to promote the ring-opening polymerization of epoxy monomers. In every case, the silyliums (R3Si+) or the N-vinylcarbazole derived cations (NVK+) are the polymerization initiating structures.
    Mots-clés : Dyes, Halogen lamp, Photoinitiators.


  • Lalevée, J.; Tehfe, M. - A.; Dumur, F.; Gigmes, D.; Blanchard, N.; Morlet-Savary, F.; Fouassier, J. P. ACS Macro Letters 2012, 1 (2), 286-290.
    Résumé : A series of iridium(III) complexes was designed and investigated as new potential photocatalysts for radical polymerization reactions. The photocatalytic reduction cycle involves the combination of an iridium complex with an amine (e.g., N-methyldiethanolamine) and an alkyl halide (e.g., phenacylbromide). The different three-component systems herein investigated are very attractive for acrylate polymerization upon visible light irradiation. They are much more reactive than those based on Ru(bpy)32+. Free radicals generated during the reaction were investigated by ESR spectroscopy and the chemical mechanisms are discussed. The crucial role played by the photocatalyst (reduction ability and excited state lifetime) is also demonstrated.

  • Lalevee, J.; Tehfe, M. - A.; Morlet-Savary, F.; Graff, B.; Dumur, F.; Gigmes, D.; Blanchard, N.; Fouassier, J. - P. Chimia 2012, 66 (6), 439-441.
    Résumé : Photoredox catalysis is now well-known in organic synthesis for the formation of free radicals under very soft irradiations conditions (e.g. sunlight, household fluorescence or LED bulbs, Xe lamp). This method has been introduced here to the polymer chemistry area to initiate ring opening polymerizations (ROP) or free radical polymerizations (FRP). The present paper will give an up-to date situation of the photocatalyst achievements in FRP and ROP.


  • Mazzolini, J.; Boyron, O.; Monteil, V.; D’Agosto, F.; Boisson, C.; Sanders, G. C.; Heuts, J. P. A.; Duchateau, R.; Gigmes, D.; Bertin, D. Polymer Chemistry 2012, 3 (9), 2383-2392.
    Résumé : Thiol end functionalized polyethylenes (PE-SH, Mn around 1000 g mol−1, Đ < 1.3) were used as nucleophiles in thia-Michael additions with different acrylic molecules. It was found that under commonly used practical conditions the addition to methacrylates was very difficult, whereas addition to acrylates was very efficient. First, block copolymers based on PE and poly(methyl methacrylate) (PMMA) were targeted by reaction of PE-SH with PMMA obtained by catalytic chain transfer polymerization (CCTP). The reaction however failed and detailed model experiments using butanethiol and a dimer of MMA showed that the solubilization temperature of PE-SH was an impediment to the success of the reaction. The lack of reactivity towards PMMA obtained by CCTP and methacrylate functions was advantageously used to react molecules containing both an acrylate and a methacrylate group in the presence of tributyl phosphine (PBu3) to produce methacrylate-type PE macromonomers. The presence of a hydroxyl function on 3-(acryloyloxy)-2-hydroxypropyl methacrylate induced side trans-esterification reactions catalyzed by PBu3. This was overcome by using the hydroxyl free 2-(acryloyloxy) ethyl methacrylate. With the latter, the desired PE macromonomer exhibited a functionality as high as 85%. Alternatively, 2-isocyanatoethyl methacrylate could also be reacted with PE-SH to produce a highly functionalized methacrylate type PE macromonomer (functionality 89%). Eventually, the efficiency of the thia-Michael addition of PE-SH onto poly(ethylene glycol) acrylate (PEG-acrylate) was used to synthesize the PE-b-PEG block copolymer.

  • Robbes, A. - S.; Cousin, F.; Meneau, F.; Chevigny, C.; Gigmes, D.; Fresnais, J.; Schweins, R.; Jestin, J. Soft Matter 2012, 8 (12), 3407-3418.
    Résumé : We present a new multi-step efficient "grafting from'' method to obtain well defined magnetic gamma-Fe2O3 nanoparticles grafted by polystyrene (PS) chains, from the synthesis of the native nanoparticles up to the refined characterization of the final grafted objects in different organic solvents, using a combination of small angle scattering (SAXS and SANS) and deuteration methods. The polymerization technique, based on a two-step Nitroxide-Mediated Polymerization (NMP), has been adapted for maghemite particles from a protocol previously established for negatively charged silica nanoparticles in dimethylacetamide (DMAc), a polar organic solvent. Such a method requires an initial inversion of the charge surface of the maghemite particles after their synthesis in an aqueous solvent. The colloidal stability of the system has been kept and controlled at every stage of the process to avoid aggregation of the particles to optimize the synthesis parameters in terms of grafting density, conversion rates, and reproducibility. The grafted objects, redispersed in different solvents, have been studied by SAXS (to characterize their gamma-Fe2O3 core) and SANS (to characterize their grafted PS corona, either hydrogenated or deuterated) at different concentrations to extract both the form factor of the object and the structure factor of the suspension. The experimental scattered curves were modelled by a Pedersen model. The parameters extracted from the model can be directly compared with the masses of the degrafted chains. The grafted objects, better dispersed in DMAc than in toluene, are organized as linear fractal aggregates of 3-4 native particles grafted with PS chains whose behavior is in agreement with scaling laws derived for brushes in a theta solvent.


  • Robbes, A. - S.; Cousin, F.; Meneau, F.; Dalmas, F.; Schweins, R.; Gigmes, D.; Jestin, J. Macromolecules 2012, 45 (22), 9220-9231.
    Résumé : We present the synthesis and structural characterization of new nanocomposites made of linear tetramers of spherical magnetic nanoparticles of maghemite (?-Fe2O3), grafted by tethered polystyrene (PS) chains with an intermediate grafting density (?0.15 chains/nm2), dispersed in a PS matrix. First, we studied by combination of SAXS and TEM the dispersion state of the grafted objects within the matrix for various ratio R of the mass of the grafted chains N to the mass of free chains P ranging from R = N/P = 0.09 to R = 2.83. For R < 0.4, we obtained ramified aggregates of a few tens of grafted objects whose compactness slightly depends on R. For R = 1, the objects are well dispersed, a case that we have studied by recovering the free untethered residual chains resulting from the synthesis of the PS-grafted nanoparticles. For R > 1, the objects are also well dispersed although there are some remaining aggregates, arising probably from the fact that we have used matrix? chains below the entanglement mass to reach such a high R values. This enabled to determine the threshold of the ?wet-to-dry? transition, between the wetting of the brush by the free chain and the expulsion of them from the brush due to entropic effects, between 0.4 and 1, a value higher than the one (0.24) obtained on a very similar system on silica spherical particles by Chevigny et al. [Macromolecules 2011, 44 (1), 122?133]. This shift highlights the influence of the curvature of the grafted objects on the threshold?s transition. Second, we have made a direct measurement of the conformation of the grafted chains in the case of aggregates, benefiting from the fact that the scattering length density (SLD) of maghemite has almost the same value as the one of deuterated PS chains. They are strongly collapsed in comparison with their conformation in bulk, as shown by a significant reduction of their radius of gyration accompanied by the deviation from a Gaussian behavior. Finally, by applying a magnetic field during casting on samples for R < 0.4, we showed that the aggregates can be aligned in the direction of the magnetic field. We demonstrate thus the possibility of tuning the structure of the fillers by coupling a double control: chemical and magnetic.


  • Rollet, M.; Glé, D.; Phan, T. N. T.; Guillaneuf, Y.; Bertin, D.; Gigmes, D. Macromolecules 2012, 45 (17), 7171-7178.
    Résumé : Separation of functional poly(ethylene oxide) PEO and PEO block copolymers was investigated using liquid chromatography under critical conditions (LCCC) with a mixture of organic solvents as eluent. The optimum eluent is a mixture of 58.05% chloroform, 6.45% methanol, and 35.50% n-heptane (v/v/v) using a reverse phase (C8) column. Unlike what was expected, the elution mechanism is governed by the interaction of a polar end-group with the column. In these conditions, poly(ethylene oxide) (PEO) functionalized with either an acrylate or alkoxyamine moieties were separated. This allows us to investigate the efficiency of the synthesis of poly(ethylene oxide)-b-polystyrene (PEO-b-PS) and polystyrene-b-poly(ethylene oxide) b-polystyrene (PS-b-PEO-b-PS) block copolymers prepared via the combination of 1,2 radical intermolecular addition followed by the nitroxide-mediated polymerization NMP of styrene. Amphiphilic diblock PEO-b-PS and triblock PS-b-PEO-b-PS copolymers were also separated from PEO homopolymers using the same experimental conditions. We showed that the PEO block is then invisible, and the calibration curve obtained using PS homopolymer standards could be used to determine the whole molar mass of the PS block in block copolymers with PS and PEO segments, with a weak influence of the architecture.

  • Stals, P. J. M.; Phan, T. N. T.; Gigmes, D.; Paffen, T. F. E.; Meijer, E. W.; Palmans, A. R. A. Journal of Polymer Science Part a-Polymer Chemistry 2012, 50 (4), 780-791.
    Résumé : Several (protected) amine and alcohol functionalized styrene monomers were synthesized via readily accessible synthetic routes. The controlled radical copolymerization of these functionalized styrene monomers with styrene was performed using two alkoxyamines, namely N-(2-methylpropyl)-N-(1-diethylphosphono-2,2-dimethylpropyl)-O-(2-carbox ylprop-2-yl) hydroxylamine (MAMA-SG1) and N-tert-butyl-N-(2-methyl-1-phenylpropyl)-O-(1-phenylethyl)hydroxylamine. The copolymers obtained showed low polydispersities, controlled molecular weights, and a random topology. The thermal properties of the polymers were determined with differential scanning calorimetry. All polymers were amorphous and showed glass transition temperatures between


  • Tehfe, M. - A.; Dumur, F.; Graff, B.; Morlet-Savary, F.; Fouassier, J. - P.; Gigmes, D.; Lalevée, J. Macromolecules 2012, 45 (21), 8639-8647.
    Résumé : Trifunctional photoinitiators (tPIs) based on benzophenone, anthracene, and pyrene chromophores linked to a triazine moiety are proposed as new initiating systems. In combination with an iodonium salt and a silane, these structures are able to initiate the radical polymerization RP of acrylates and the cationic polymerization CP of epoxides and vinylethers under Xe?Hg lamp, LED and very soft irradiation (i.e., halogen lamp). Upon addition of an amine, these new photoinitiators were also able to start the radical polymerization of acrylates. Excellent RP and CP polymerization profiles are obtained i.e. better than those recorded using the reference compounds (benzophenone, anthracence and pyrene). In CP, some of these compounds combined with thianthrenium salts can also be used. The mechanisms involved in the different multicomponent initiating systems were analyzed by ESR, fluorescence, steady state photolysis, and laser flash photolysis experiments.


  • Tehfe, M. - A.; Gigmes, D.; Dumur, F.; Bertin, D.; Morlet-Savary, F.; Graff, B.; Lalevée, J.; Fouassier, J. - P. Polymer Chemistry 2012, 3 (7), 1899-1902.
    Résumé : New photoinitiating systems allowing an efficient cationic photopolymerization of epoxides under air using different diode lasers are presented. These new photoinitiating systems are based on various three-component photoinitiating systems i.e. violanthrone-78 (or violanthrone-79, tris(2,2′-bipyridine)ruthenium(II) dichloride, methylene blue, and iridium(III) complexes)/diphenyl iodonium salt/tris(trimethylsilyl)silane. Excellent polymerization profiles with high monomer conversions were obtained. These results allow the design of less shrinkable high speed photopolymers usable in the visible wavelength range for a variety of applications in e.g. the manufacture of optical elements. A reaction mechanism is also proposed.


  • Tehfe, M. - A.; Lalevée, J.; Telitel, S.; Contal, E.; Dumur, F.; Gigmes, D.; Bertin, D.; Nechab, M.; Graff, B.; Morlet-Savary, F.; Fouassier, J. - P. Macromolecules 2012, 45 (11), 4454-4460.
    Résumé : Different polyaromatic structures (truxene derivatives and tris(aza)pentacene) are presented as new metal-free organic photocatalysts (OPC) to promote free radical polymerization FRP and ring-opening polymerization (ROP) under halogen lamp, household LED bulb, and laser diode (405 nm). These OPCs exhibit interesting light absorption properties and lead, through an oxidative catalytic cycle, to the formation of radicals and ions that can initiate both free radical polymerization FRP and ring-opening polymerization ROP. Interestingly, excellent polymerization profiles are obtained even upon visible light exposure. Using these very soft irradiation conditions, acrylate/epoxide blends are also easily polymerized under air and lead to the formation of interpenetrated polymer networks IPN exhibiting no phase separation.

  • Tyagi, P.; Deratani, A.; Bouyer, D.; Cot, D.; Gence, V.; Barboiu, M.; Phan, T. N. T.; Bertin, D.; Gigmes, D.; Quemener, D. Angewandte Chemie-International Edition 2012, 51 (29), 7166-7170.


  • Wantz, G.; Gautier, B.; Dumur, F.; Phan, T. N. T.; Gigmes, D.; Hirsch, L.; Gao, J. Organic Electronics 2012, 13 (10), 1859-1864.
    Résumé : Light-emitting electrochemical cells (LECs) based on a semiconducting polymer blended with lithium salt and novel polyelectrolytes have been studied. Random copolymers of poly(ethylene glycol) methyl ether methacrylate have been developed in order to increase their glass transition temperature (Tg) above room temperature. Devices have been optimized and successfully turned on upon heating. Cooling devices under applied voltage bias down to room temperature leads to frozen PN junctions. The relaxation of these junctions over voltage-free storage is studied. The higher the Tg, the longer the shelf-life of the junctions. This research opens the route to room temperature stable organic PN junctions for use in organic electronic devices such as light-emitting diodes, photovoltaic solar cells and other organic electronic devices.
    Mots-clés : High-Tg polymer electrolyte, Light-emitting electrochemical cell, P–N junction, Room temperature frozen junction.
2011


  • Bertin, D.; Gigmes, D.; Marque, S. R. A.; Tordo, P. Chemical Society Reviews 2011, 40 (5), 2189-2198.
    Résumé : Due to the academic and industrial interest of Nitroxide Mediated Polymerization (NMP), a lot of investigations have focused on the kinetics of this process. During the last decade, although the simplified kinetic scheme—equilibrium reactions between dormant species (alkoxyamine) and active species (alkyl radicals and nitroxides), propagation reaction of the macro-alkyl radical, and termination reactions—was suitable to predict the main trends at the macromolecular level, it has become obvious that it was not sufficient to describe all the kinetic effects involved in the NMP process. Indeed, like the conventional radical polymerization, NMP should be described as a 3 stage process including initiation, propagation, and self- and cross-termination. These two types of radical polymerization differ by the occurrence during NMP of an activation/deactivation process involving the dormant species in both the initiation and propagation stages. Evidence is provided of the importance of the rate of homolysis of the initiator (alkoxyamines) and of the rate of the first alkyl radical addition onto the monomer for the success of NMP. Thus, the fundamental kinetics of the main reactions involved in NMP as well as side-reactions are also discussed in this tutorial review.


  • Chevigny, C.; Dalmas, F.; Di Cola, E.; Gigmes, D.; Bertin, D.; Boué, F.; Jestin, J. Macromolecules 2011, 44 (1), 122-133.
    Résumé : We investigate the dispersion mechanisms of nanocomposites made of well-defined polymer (polystyrene, PS) grafted-nanoparticles (silica) mixed with free chains of the same polymer using a combination of scattering (SAXS/USAXS) and imaging (TEM) techniques. We show that the relevant parameter of the dispersion, the grafted/free chains mass ratio R tuned with specific synthesis process, enables to manage the arrangement of the grafted nanoparticles inside the matrix either as large and compact aggregates (R < 0.24) or as individual nanoparticles dispersion (R > 0.24). From the analysis of the interparticles structure factor, we can extract the thickness of the spherical corona of grafted brushes and correlate it with the dispersion: aggregation of the particles is associated with a significant collapse of the grafted chains, in agreement with the theoretical models describing the free energy as a combination of a mixing entropy term between the free and the grafted chains and an elastic term of deformation of the grafted brushes. At fixed grafting density, the individual dispersion of particles below the theoretical limit of R = 1 can be observed, due to interdiffusion between the grafted and the free chains but also to processing kinetics effects, surface curvature and chains poly dispersity. Mechanical analysis of nanocomposites show the appearance of a longer relaxation time at low frequencies, more pronounced in the aggregated case even without direct connectivity between the aggregates. Correlation between the local structure and the rheological behavior suggests that the macroscopic elastic modulus of the nanocomposite could be described mainly by a short-range contribution, at the scale of the interactions between grafted particles, without significant effect of larger scale organizations.


  • Chevigny, C.; Gigmes, D.; Bertin, D.; Schweins, R.; Jestin, J.; Boué, F. Polymer Chemistry 2011, 2 (3), 567-571.
    Résumé : We synthesized well-defined polystyrene-grafted silica nanoparticles by adapting our previous synthesis process without using free initiator. We were able to obtain a more versatile system in which we can tune the masses of the grafted chains while controlling the polymerization, the colloidal stability and avoid the formation of free polymer chains. The final grafted objects were characterized in a refined way using SANS and the contrast matching method.

  • Clement, B.; Decherchi, P.; Feron, F.; Bertin, D.; Gigmes, D.; Trimaille, T.; Marqueste, T. Macromolecular Bioscience 2011, 11 (9), 1175-1184.
    Résumé : The properties of poly(D,L-lactide)-block-poly(2-hydroxyethyl acrylate) (PLA-b-PHEA) block copolymers by means of in vitro / in vivo (rat) degradation are investigated and compared to those of PLA homopolymer. Over 12 weeks, we observe mass loss and molecular weight decrease. In vitro and in vivo findings are very similar for each polymer tested. When a short PHEA block is used (PLA-b-PHEA 15 000-3 000 g.mol(-1), 85/15 wt%), the degradation process is found to be very similar to that of homo-PLA, and to be typical of a bulk erosion mechanism, with no mass loss observed until week 7 and continuous decrease of molar mass within this timeframe. For a longer PHEA block length within the block copolymer (PLA-b-PHEA 15 000-7 500 g.mol(-1), 65/35 wt%), the degradation mechanism is modified, with a significant mass loss observed at early times and only a slight decrease in molar mass. The latter finding is related to the pronounced hydrophilicity and softness of the material induced by the PHEA block, which allow easy diffusion and rapid leakage of the degradation residues from the material towards the aqueous medium. Schwann cells are found to better adhere on spin-coated films of PLA-b-PHEA (85/15 wt%) than on PLA ones. These results show the potential of such hydrophilized PLA-based copolymers for use in peripheral nerve repair.


  • Dumur, F.; Bertin, D.; Mayer, C. R.; Guerlin, A.; Wantz, G.; Nasr, G.; Dumas, E.; Miomandre, F.; Clavier, G.; Gigmes, D. Synthetic Metals 2011, 161 (17–18), 1934-1939.
    Résumé : A phosphorescent cyclometalated heteroleptic Ir(III) complex was investigated as emitter for light-emitting electrochemical cells (LECs) and polymer organic light-emitting diodes (POLEDs). By exploring the deposition conditions of the emissive layer in multilayered electroluminescent devices, we directly impacted the emission color by mixing or not the complex with poly(vinylcarbazole) (PVK). Strategy of emission color tuning enabled to produce blue or yellow emitting devices. Heteroleptic complex was characterized by UV–visible absorption and luminescence spectroscopy. Cyclic voltammetry and DFT calculations were also performed.
    Mots-clés : Color tunability, Host–guest strategy, Iridium complex, Light-emitting electrochemical cells, Organic light emitting diode.

  • Dumur, F.; Guerlin, A.; Dumas, E.; Bertin, D.; Gigmes, D.; Mayer, C. R. Gold Bulletin 2011, 44 (2), 119-137.

  • Dumur, F.; Guillaneuf, Y.; Guerlin, A.; Wantz, G.; Bertin, D.; Miomandre, F.; Clavier, G.; Gigmes, D.; Mayer, C. R. Macromolecular Chemistry and Physics 2011, 212 (15), 1616-1628.
    Résumé : The synthesis of two random copolymers bearing pendant mixed-ligand orthometallated terpyridine-based cationic iridium (III) complexes, as well as their uses as single-layered electrophosphorescent emitters in polymer light-emitting diodes is described. Both solution-processable iridium metallopolymers are prepared by copolymerization of styrene with a complex-substituted styrene by nitroxide mediated polymerization. Results on devices based on metallopolymers used as dopant of poly(N-vinylcarbazole) or alone as single layers are presented.


  • Dumur, F.; Nasr, G.; Wantz, G.; Mayer, C. R.; Dumas, E.; Guerlin, A.; Miomandre, F.; Clavier, G.; Bertin, D.; Gigmes, D. Organic Electronics 2011, 12 (10), 1683-1694.
    Résumé : Phosphorescent Organic Light-Emitting Diodes (PhOLEDs) based on iridium (III) soft salt were designed and studied. Heteroleptic anionic iridium complex (A) was prepared with thiocyanate anions and cationic iridium complex (C) was synthesized with 4,4′-dinonyl-2,2′-byridine as the ancillary ligand. Electronic and spectroscopic properties of the resulting combination of soft salt C·A were investigated by mean of UV–visible absorption, fluorescence spectroscopy and cyclic voltammetry. DFT calculations were also performed and the electroluminescent performances evaluated. Light-emitting electrochemical cells (LECs) displaying color-variable emission were also obtained. This color tunability aroused from a modification of the molecular packing of the emissive layer with the temperature.
    Mots-clés : Iridium complex, PhOLED, Phosphorescence, Soft complex, Thiocyanate.


  • Gigmes, D.; Dufils, P. - E.; Glé, D.; Bertin, D.; Lefay, C.; Guillaneuf, Y. Polymer Chemistry 2011, 2 (8), 1624-1631.
    Résumé : This review described the potential of the intermolecular radical 1,2-addition from the commercially available BlocBuilder MA alkoxyamine onto activated olefins to synthesize either new functionalized alkoxyamines or various macromolecular architectures. Following this approach, diblock, triblock copolymers, star polymers and hybrid materials are then easily prepared. The various applications of such architectures will be briefly reviewed. Interestingly this new synthetic tool widely expands the range of complex macromolecular architectures which could be obtained by the nitroxide-mediated polymerization (NMP) process.

  • Handke, N.; Trimaille, T.; Luciani, E.; Rollet, M.; Delair, T.; Verrier, B.; Bertin, D.; Gigmes, D. Journal of Polymer Science Part a-Polymer Chemistry 2011, 49 (6), 1341-1350.
    Résumé : Poly(N-acryloxysuccinimide) (PNAS) and poly(N-acryloxysuccinimide-co-N-vinylpyrrolidone) (P(NAS-co-NVP)) of adjustable molecular weights and narrow polydispersities were prepared by nitroxide-mediated polymerization (NMP) in N,N-dimethylformamide in the presence of free SG1 (N-tert-butyl-N-1-diethylphosphono-)2,2-dimethylpropyl) nitroxide), with MAMA-SG 1 (N-(2-methylpropyl)-N-(1-diethylphosphono-2,2-dimethylpropyl)-O-(2-carbo xylprop-2-yl)hydroxylamine) alkoxyamine as initiator. The reactivity ratios of NAS and NVP were determined to be r(NAS) = 0.12 and r(NVP) = 0, indicating a strong alternating tendency for the P(NAS-co-NVP) copolymer. NAS/NVP copolymerization was then performed from a SG1-functionalized poly(D,L-lactice) (PLA-SG1) macro-alkoxyamine as initiator, leading to the corresponding PLA-b-P(NAS-co-NVP) block copolymer, with similar NAS and NVP reactivity ratios as mentioned above. The copolymer was used as a surface modifier for the PLA diafiltration and nanoprecipitation processes to achieve nanoparticles in the range of 450 and 150 nm, respectively. The presence of the functional/hydrophilic P(NAS-co-NVP) block, and particularly the N-succinimidyl (NS) ester moieties at the particle surface, was evidenced by ethanolamine derivatization and zeta potential measurements. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 13411350, 2011


  • Lalevée, J.; Blanchard, N.; Tehfe, M. A.; Fries, C.; Morlet-Savary, F.; Gigmes, D.; Fouassier, J. P. Polymer Chemistry 2011, 2 (5), 1077-1084.
    Résumé : The ability of a new efficient photoinitiator (TX–Si), based on the well-known thioxanthone chromophore linked to a disilylacetylene moiety and exhibiting a red-shifted absorption, to initiate both free radical polymerization and cationic polymerization is checked. A comparison with the parent compound (isopropylthioxanthone) is provided. High rates of polymerization and high final conversions are obtained. The migration of TX–Si out of the polymer film is noticeably reduced (3-fold factor) compared to that observed with ITX. A similar modification of the xanthone chromophore (XT–Si) also leads to an efficient cleavable photoinitiator and opens a door for the design of a new class of potentially interesting compounds for UV curing applications. As characterized by ESR spin trapping, TX–Si and XT–Si generate silyl radicals under light irradiation evidencing a Type I photoinitiator character. The analysis of the excited state processes through laser flash photolysis and molecular orbital calculations allows explaining the observed photochemical behavior.


  • Lalevée, J.; Blanchard, N.; Tehfe, M. - A.; Peter, M.; Morlet-Savary, F.; Gigmes, D.; Fouassier, J. P. Polymer Chemistry 2011, 2 (9), 1986-1991.
    Résumé : A new concept based on the photoredox catalysis is proposed for the design of a photoinitiating system able to efficiently generate, in a single catalytic cycle, both a radical and a cation as initiating species. This is exemplified here by the tris(1,10-phenanthroline)ruthenium(II) (Ru(phen)32+) complex in combination with a diphenyl iodonium salt and a silane. Interesting and promising photopolymerization profiles in free radical photopolymerization (FRP) and free radical promoted cationic photopolymerization (FRPCP) are obtained under air and upon xenon lamp exposure and even soft irradiation conditions (fluorescence bulb, sunlight). An acrylate/epoxide blend is also easily polymerized under air using a fluorescent bulb. The mechanisms are investigated by ESR and Laser Flash Photolysis experiments.

  • Lalevee, J.; Peter, M.; Dumur, F.; Gigmes, D.; Blanchard, N.; Tehfe, M. - A.; Morlet-Savary, F.; Fouassier, J. P. Chemistry-a European Journal 2011, 17 (52), 15027-15031.
    Résumé : Iridium(III) complexes were designed and evaluated as efficient photoinitiators of polymerization reactions in combination with iodonium salts and silanes. Mechanistically, these reactions were shown to proceed through oxidative photoredox catalysis, generating aryl and silyl radicals under very soft irradiation conditions (blue LED, xenon lamp, and even sunlight). These radicals can initiate the free radical polymerization of acrylates or can be oxidized during the catalytic cycle to promote the ring-opening polymerization of epoxy monomers. Remarkably, both the (photo)chemical reactivity and the practical efficiency are dramatically affected by the ligands. In addition, the central role played by the oxidation ability of the excited state of the photocatalyst is discussed.