References of "Jérôme, Christine"
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See detailCarbon dioxide, a cheap bio-sourced building block for cyclic carbonates and non-isocyanate polyurethanes
Gennen, Sandro ULg; Alves, Margot ULg; Tassaing, Thierry et al

Poster (2015, May 03)

Due to concerns about global warming combined with the decrease of fossil resources, new carbon feedstocks that are abundant, renewable, non-toxic, inexpensive and environmentally friendly must be ... [more ▼]

Due to concerns about global warming combined with the decrease of fossil resources, new carbon feedstocks that are abundant, renewable, non-toxic, inexpensive and environmentally friendly must be explored to produce chemicals. Besides the valorization of bio-based raw materials, the chemical transformation of carbon dioxide into added-value products has gained interest in both academia and industry. To date, the chemical fixation of CO2 onto epoxides with the formation of cyclic carbonates is one of the most promising ways to valorize CO2 at an industrial scale. Indeed, cyclic carbonates find applications as electrolytes in lithium ion batteries, as aprotic polar solvents or as useful intermediates for polycarbonates. Cyclic carbonates also react with primary amines to produce 2-hydroxyethylurethane. This reaction can be extrapolated to the synthesis of non-isocyanate polyurethanes (NIPU) by polyaddition of bifunctional cyclic carbonates with diamines.5 This study aims (i) at developing a new highly efficient organocatalyst for the synthesis of cyclic carbonates under mild experimental conditions and (ii) their valorization as monomers to produce non-isocyanate polyurethanes. First, we have identified a bicomponent organocatalyst, composed of a judicious combination of an organocatalyst and an activator, for the very fast synthesis of cyclic carbonates from CO2 and epoxides under very mild reaction conditions. Kinetics of reactions were followed by online Raman spectroscopy measurements under pressure. NMR titrations were realized to evidence the mechanism of activation of this novel organocatalytic system that will be discussed in detail in this talk. The second objective relies on the development of new efficient organocatalysts for the synthesis of high molar masses NIPUs in short reaction times. Organic compounds interacting with the cyclic carbonate by hydrogen bonding were identified and their catalytic activity was demonstrated for model compounds. [less ▲]

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See detailControlled synthesis of ethylene-vinyl acetate based copolymers by organometallic mediated radical polymerization
Demarteau, Jérémy ULg; Kermagoret, Anthony ULg; Jérôme, Christine ULg et al

in Matyjaszewski, Krzysztof; Sumerlin, Brent S.; Tsarevsky, Nicolay V. (Eds.) et al Controlled Radical Polymerization: Materials (2015)

The controlled radical copolymerization of ethylene (E) and vinyl acetate (VAc) is further investigated by organometallic- mediated radical polymerization (OMRP) using Co(acac)2 as controlling agent at ... [more ▼]

The controlled radical copolymerization of ethylene (E) and vinyl acetate (VAc) is further investigated by organometallic- mediated radical polymerization (OMRP) using Co(acac)2 as controlling agent at ethylene pressure up to 100 bar. The effect of ethylene pressure on kinetics, level of control and copolymer composition, is discussed. Ethylene-Vinyl Acetate copolymers (EVAs) with low dispersities and ethylene content reaching 57 mol% are notably reported. This work also successfully addresses the precision design of EVA-containing block copolymers, i.e. PVAc-block-EVA. In this case, the order of the synthesis of the blocks is a key parameter. The “PVAc-first” strategy is by far more practical and efficient. [less ▲]

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See detailLinear and propeller-like fluoro-isoindigo based donor–acceptor small molecules for organic solar cells
Ouhib, Farid ULg; Tomassetti, Mirco ULg; Dierckx, Wauter et al

in Organic Electronics (2015), 20

Two donor–acceptor type fluoro-isoindigo based small molecule semiconductors are syn- thesized and their optical, electrochemical, thermal, and charge transport properties are investigated. The two ... [more ▼]

Two donor–acceptor type fluoro-isoindigo based small molecule semiconductors are syn- thesized and their optical, electrochemical, thermal, and charge transport properties are investigated. The two molecular chromophores differ by their architecture, linear (M1) vs propeller-like (M2). Both molecules present a broad absorption in the visible range and a low optical HOMO–LUMO gap (?1.6 eV). AFM images of solution-processed thin films show that the trigonal molecule M2 forms highly oriented fibrils after a few seconds of solvent vapor annealing. The materials are evaluated as electron donor components in bulk heterojunction organic solar cells using PC61BM as the electron acceptor. The devices based on the propeller-like molecule M2 exhibit a high open-circuit voltage (around 1.0 V) and a power conversion efficiency of 2.23%. [less ▲]

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See detailMussel-inspired protein-repelling ambivalent block copolymers: controlled synthesis and characterization
Patil, Nagaraj ULg; Falentin-Daudré, Céline; Jérôme, Christine ULg et al

in Polymer Chemistry (2015), 6(15), 2919-2933

This paper describes the reversible addition–fragmentation chain transfer (RAFT) polymerization of mussel-inspired acetonide-protected dopamine (meth)acrylamide monomers (ADA and ADMA) and its ... [more ▼]

This paper describes the reversible addition–fragmentation chain transfer (RAFT) polymerization of mussel-inspired acetonide-protected dopamine (meth)acrylamide monomers (ADA and ADMA) and its implementation to the synthesis of innovative ambivalent block copolymers. They consist of a hydro- phobic poly((meth)acrylamide) block functionalized by catechols and a hydrophilic segment of a poly- ((meth)acrylate) bearing pendent PEG chains. For the first time, a series of well-defined P(PEGAm-b-ADAn) and P(ADMAn-b-PEGMAm) diblock copolymers across a range of molar masses (13–42 kg mol−1) with low molar mass dispersities (Đ = 1.12 − 1.25) were reported. Post polymerization, trifluoroacetic acid (TFA) treatment yields block copolymers bearing free-catechol units in quantitative yields (>95%) with a slight noticeable hydrolysis of pendent-PEG units (2%–4%). The self-assembly of the amphiphilic block copoly- mers into spherical micelles was demonstrated by 1H NMR, DLS and TEM imaging techniques. Real-time quartz crystal microbalance with dissipation monitoring (QCM-D) studies revealed that free-catechol groups were necessary for a strong anchoring onto gold and stainless steel surfaces because acetonide- protected and catechol-oxidized block copolymers completely desorbed from the surface in the rinsing step. The ambivalent nature of catechol functionalized block copolymers was studied by bovine serum albumin (BSA) adsorption on polymer modified surfaces, which displayed improved resistance against BSA adsorption, when compared to an unmodified surface. [less ▲]

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See detailChitosan-coated nanofibers for wound dressing
Croisier, Florence ULg; Colige, Alain ULg; Jérôme, Christine ULg

Conference (2015, March 23)

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See detailCarbon dioxide and vegetable ooil for the synthesis of bio-based polymer precursor
Alves, Margot ULg; Méreau, Raphaël; Grignard, Bruno ULg et al

Conference (2015, March 18)

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See detailDouble thermo-responsive hydrogels from poly(vinylcaprolactam) containing diblock and triblock copolymers
Thomassin, Jean-Michel ULg; Mathieu, Kevin ULg; Kermagoret, Anthony ULg et al

in Polymer Chemistry (2015), 6(10), 1856-1864

The thermally-induced gelation and gel properties of concentrated aqueous solutions of double thermoresponsive poly(N-vinylamide)-based di- and triblock copolymers are studied by rheology. The copolymers ... [more ▼]

The thermally-induced gelation and gel properties of concentrated aqueous solutions of double thermoresponsive poly(N-vinylamide)-based di- and triblock copolymers are studied by rheology. The copolymers under investigation, prepared by cobalt-mediated radical polymerization and coupling reactions, are composed of poly(vinylcaprolactam) (PNVCL) blocks and of a statistical poly(vinylcaprolactam-stat-vinylpyrrolidone) segment with a cloud point temperature (TCP) higher than that of PNVCL. Heating the di- and triblock solutions beyond the first phase transition temperature favors gel formation while heating above the second TCP leads to opaque gels without macroscopic demixing. Moduli of the triblock hydrogels are systematically higher than those of the corresponding diblocks, even above the second transition. Rheological data suggest distinct micellar structures for each copolymer architecture: densely packed micelles of diblocks and 3-D networks of bridged micelles for triblocks. Strain sweep experiments also emphasize the positive effect of the micelle bridging on the elasticity and stability of the hydrogels. The formation and properties of the obtained gels are also shown to depend on the copolymer concentration, block length, and composition. Addition of salt also allows us to tune the phase transition temperatures of these double thermoresponsive hydrogels. [less ▲]

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See detailGradient foaming of polycarbonate/carbon nanotube based nanocomposites with supercritical carbon dioxide and their EMI shielding performances
Monnereau, Laure; Urbanczyk, Laetitia; Thomassin, Jean-Michel ULg et al

in Polymer (2015), 59

Sorption and diffusion of supercritical carbon dioxide (scCO2) into polycarbonate (PC) nanocomposites loaded with 0, 1 and 2 wt% of multi-walled carbon nanotubes (MWNTs) have been investigated. After ... [more ▼]

Sorption and diffusion of supercritical carbon dioxide (scCO2) into polycarbonate (PC) nanocomposites loaded with 0, 1 and 2 wt% of multi-walled carbon nanotubes (MWNTs) have been investigated. After determination of the saturation equilibrium, the samples have been saturated with scCO2 to ensure a partial foaming with a density gradient from the surface to the center of the samples and the morphology of the porous materials has been analysed by SEM. The gradient materials were very advantageous for EMI shielding since the foamed structure at the surface had low dielectric constant and limited the reflection of the EM signal while the presence of highly conductive solid in the middle ensured a high absorption of the electromagnetic radiation. [less ▲]

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See detailIn situ investigation of scCO2 assisted impregnation of drug into polymer by high pressure FTIR micro-spectroscopy
Champeau, Mathilde ULg; Thomassin, Jean-Michel ULg; Jérôme, Christine ULg et al

in Analyst (2015), 140(3), 869-879

An original experimental set-up combining a FTIR microscope with a high pressure cell has been built in order to analyze in-situ the impregnation of solute into microscopic polymer samples, such as fibers ... [more ▼]

An original experimental set-up combining a FTIR microscope with a high pressure cell has been built in order to analyze in-situ the impregnation of solute into microscopic polymer samples, such as fibers or films, subjected to supercritical CO2. Thanks to this experimental set-up, key factors governing the impregnation process can be simultaneously followed such as the swelling of the polymeric matrix, the CO2 sorption, the kinetic of impregnation and the drug loading into the matrix. Moreover, the solute/polymer interactions and the speciation of the solute can be analyzed. We have monitored in situ the impregnation of aspirin and ketoprofen into PEO (Polyethylene Oxide) platelets at T=40°C and P=5; 10 and 15 MPa. The kinetic of impregnation of aspirin was quicker than the one of ketoprofen and the final drug loading was also higher in case of aspirin. Whereas the CO2 sorption and the PEO swelling remain constant when PEO is just subjected to CO2 under isobaric conditions, we noticed that both parameters can increase while the drug impregnates PEO. Coupling these results with DSC measurements, we underlined the plasticizing effect of the drug that also leads to decrease the crystallinity of PEO in situ thus favoring the sorption of CO2 molecules into the matrix and the swelling of the matrix. The plasticizing effect increases with the drug loading. Finally, the speciation of drug was investigated considering the shift of the carboxyl bands of the drugs. Both drugs were found to be mainly homogeneously dispersed into PEO. [less ▲]

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See detailIn situ bidentate to tetradentate ligand exchange reaction in cobalt-mediated radical polymerization
Kermagoret, Anthony ULg; Jérôme, Christine ULg; Detrembleur, Christophe ULg et al

in European Polymer Journal (2015), 62

Organometallic-mediated radical polymerization (OMRP) has seen a significant growth in the last years notably due to the development of new metal complexes, especially cobalt derivatives. Despite of this ... [more ▼]

Organometallic-mediated radical polymerization (OMRP) has seen a significant growth in the last years notably due to the development of new metal complexes, especially cobalt derivatives. Despite of this, none of the reported complexes offers optimal control for monomers with very different reactivity, which somewhat limits the synthesis of copolymers. In order to expand the scope of cobalt-mediated radical polymerization (CMRP), we investigated an in situ ligand exchange reaction for modulating the properties of the cobalt complex at the polymer chain-end and adjusting the C-Co bond strength involved in the control process. With the aim of improving the synthesis of poly(vinyl acetate)-b-poly(n-butyl acrylate) copolymers, bidentate acetylacetonate ligands, which impart high level of control to the polymerization of vinyl acetate (VAc), were replaced in situ at the PVAc-cobalt chain-end by tetradentate Salen type ligands that are more suited to acrylates. [less ▲]

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See detailInfluence of the protein context on the polyglutamine length-dependent elongation of amyloid fibrils
Huynen, Céline ULg; Willet, Nicolas ULg; Buell, Alexander K. et al

in Biochimica et Biophysica Acta-Proteins and Proteomics (2015), 1854

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See detailDual stimuli-responsive coating designed through layer-by-layer assembly of PAA-b-PNIPAM block copolymers for the control of protein adsorption
Osypova, Alina; Magnin, Delphine; Sibret, Pierre ULg et al

in Soft Matter (2015), 11(41), 8154-8164

In this paper, we describe the successful construction, characteristics and interaction with proteins of stimuli-responsive thin nanostructured films prepared by layer-by-layer (LbL) sequential assembly ... [more ▼]

In this paper, we describe the successful construction, characteristics and interaction with proteins of stimuli-responsive thin nanostructured films prepared by layer-by-layer (LbL) sequential assembly of PNIPAM-containing polyelectrolytes and PAH. PAA-b-PNIPAM block copolymers were synthesized in order to benefit from (i) the ionizable properties of PAA, to be involved in the LbL assembly, and (ii) the sensitivity of PNIPAM to temperature stimulus. The impact of parameters related to the structure and size of the macromolecules (their molecular weight and the relative degree of polymerization of PAA and PNIPAM), and the interaction with proteins under physico-chemical stimuli, such as pH and temperature, are carefully investigated. The incorporation of PAA-b-PNIPAM into multilayered films is shown to be successful whatever the block copolymer used, resulting in slightly thicker films than the corresponding (PAA/PAH)n film. Importantly, the protein adsorption studies demonstrate that it is possible to alter the adsorption behavior of proteins on (PAA-b-PNIPAM/PAH)n surfaces by varying the temperature and/or the pH of the medium, which seems to be intimately related to two key factors: (i) the ability of PNIPAM units to undergo conformational changes and (ii) the structural changes of the film made of weak polyelectrolytes. The simplicity of construction of these PNIPAM block copolymer-based LbL coatings on a large range of substrates, combined with their highly tunable features, make them ideal candidates to be employed for various biomedical applications requiring the control of protein adsorption. [less ▲]

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See detailSmall Angle X-ray Scattering Insights into the Architecture-Dependent Emulsifying Properties of Amphiphilic Copolymers in Supercritical Carbon Dioxide
Alaimo, David ULg; Hermida Merino, Daniel; Grignard, Bruno ULg et al

in Journal of Physical Chemistry B (2015), 119

The supramolecular assembly of a series of copolymers combining a PEO-rich hydrophilic and fluorinated CO2-philic sequences is analysed by synchrotron small-angle xray scattering (SAXS) in supercritical ... [more ▼]

The supramolecular assembly of a series of copolymers combining a PEO-rich hydrophilic and fluorinated CO2-philic sequences is analysed by synchrotron small-angle xray scattering (SAXS) in supercritical CO2, as well as in water/CO2 emulsions. These copolymers were designed to have the same molecular weight and composition, and to differ only by their macromolecular architecture. The investigated copolymers have random, block, and palm-tree architectures. Besides, thermo-responsive copolymer is also analysed, having a hydrophilic sequence becoming water-insoluble around 41 °C, i.e. just above the critical point of CO2. At the length scale investigated by SAXS, only the random copolymer appears to self-assemble in pure CO2, in the form of a disordered microgel-like network. The random, block and thermo-responsive copolymers are all able to stabilize water/CO2 emulsions but not the copolymer with the palm-tree architecture, pointing at the importance of macromolecular architecture for the emulsifying properties. A modelling of the SAXS data shows that the block and the thermo-responsive copolymers form spherical micelle-like structures containing about 70 % water and 30 % polymer. [less ▲]

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See detailImproved photo-induced cobalt-mediated radical polymerization in continuous flow photoreactors
Kermagoret, Anthony; Wenn, Benjamin; Debuigne, Antoine ULg et al

in Polymer Chemistry (2015), 6

The implementation of cobalt-mediated radical polymerization (CMRP) for continuous microreactor synthesis is described. We demonstrate how the utilization of flow photoreactors allows the speed up of the ... [more ▼]

The implementation of cobalt-mediated radical polymerization (CMRP) for continuous microreactor synthesis is described. We demonstrate how the utilization of flow photoreactors allows the speed up of the polymerization of vinyl acetate (VAc) under UV irradiation without loss of polymerization control. Microfluidics under UV irradiation has also been successfully implemented for the copolymerization of VAc with a less reactive olefin 1-octene (1-Oct). Reactivity ratios were deduced for this copolymerization system, and poly(VAc-co-1-Oct) copolymers containing up to 50 mol% of 1-Oct were synthesized. To the best of our knowledge, this is the first report on a photopolymerization where continuous flow techniques not only led to an improvement of reaction rates and dispersity, but also led to the avoidance of significant side-products that were observed in batch processing [less ▲]

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See detailBranched and linear A2–D–A1–D–A2 isoindigo-based solution-processable small molecules for organic field-effect transistors and solar cells
Tomassetti, Mirco ULg; Ouhib, Farid ULg; Cardinaletti, Ilaria et al

in RSC Advances (2015), 5(104), 85460-85469

To establish a correlation between the molecular structure, physicochemical properties, thin film morphology, charge carrier mobility and photovoltaic performance of isoindigo-based electron donor type ... [more ▼]

To establish a correlation between the molecular structure, physicochemical properties, thin film morphology, charge carrier mobility and photovoltaic performance of isoindigo-based electron donor type molecular semiconductors, a series of branched and linear A2–D–A1–D–A2 small molecules (A = acceptor, D = donor) are synthesized. The extended π-conjugated molecular chromophores have an electron-accepting isoindigo core, a bridging oligothiophene electron donor part and terminal octyl cyanoacrylate acceptor moieties. Their photophysical, thermal and electrochemical properties are analysed and the materials are applied in organic field-effect transistors and bulk heterojunction organic solar cells. Compared to an analogous benzothiadiazole-based small molecule, the isoindigo core deepens the HOMO energy level, enabling higher open-circuit voltages in organic solar cells. The linear isoindigo-based small molecule shows an enhanced hole mobility compared to the branched derivatives. The best power conversion efficiency of the investigated set is also obtained for the solar cell based on the linear (CA-3T-IID-3T-CA-l) donor molecule in combination with PC71BM. [less ▲]

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