References of "Kermagoret, Anthony"
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See detailPrecision design of ethylene- and polar-monomer-based copolymers by organometallic-mediated radical polymerization
Kermagoret, Anthony ULg; Debuigne, Antoine ULg; Jérôme, Christine ULg et al

in Nature Chemistry (2014), 6(3), 179-187

The copolymerization of ethylene with polar monomers is a major challenge when it comes to the manufacture of materials with potential for a wide range of commercial applications. In the chemical industry ... [more ▼]

The copolymerization of ethylene with polar monomers is a major challenge when it comes to the manufacture of materials with potential for a wide range of commercial applications. In the chemical industry, free-radical polymerization is used to make a large proportion of such copolymers, but the forcing conditions result in a lack of fine control over the architecture of the products. Herein we introduce a synthetic tool, effective under mild experimental conditions, for the precision design of unprecedented ethylene- and polar-monomer-based copolymers. We demonstrate how an organocobalt species can control the growth of the copolymer chains, their composition and the monomer distribution throughout the chain. By fine tuning the ethylene pressure during polymerization and by exploiting a unique reactive mode of the end of the organometallic chain, novel block-like copolymer structures can be prepared. This highly versatile synthetic platform provides access to a diverse range of polymer materials. [less ▲]

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See detailExpanding the scope of controlled radical polymerization via cobalt–tellurium radical exchange reaction
Kermagoret, Anthony ULg; Nakamura, Yasuyuki; Bourguignon, Maxime et al

in ACS Macro Letters (2014), 3(1), 114-118

Cobalt-mediated radical polymerization (CMRP) and tellurium-mediated radical polymerization (TERP) were combined for the first time, offering new perspectives in the precision design of macromolecular ... [more ▼]

Cobalt-mediated radical polymerization (CMRP) and tellurium-mediated radical polymerization (TERP) were combined for the first time, offering new perspectives in the precision design of macromolecular structures. In particular, the present work highlights the benefits of this strategy for the synthesis of novel poly(vinyl acetate)-based block copolymers. A range of well-defined poly(vinyl acetate)s (PVAc) were first produced via CMRP using the bis(acetylacetonato)cobalt(II) complex (Co(acac)2) as a regulating agent. Substitution of a methyltellanyl moiety for Co(acac)2 at the ω-chain end of the precursor was then achieved upon treatment with dimethylditelluride. In contrast to the PVAc prepared by TERP, the ones produced by sequential CMRP and Co/Te exchange reaction almost exclusively consist of regular head-to-tail-TeMe chain-end species that can be activated by TERP. Ultimately, a series of monomers problematic in Co(acac)2-mediated radical polymerization including N-isopropylacrylamide (NIPAM), 2-(dimethylamino)ethyl acrylate (ADAME), n-butyl acrylate (BA), isoprene (IP), and vinylimidazole (NVIm) were polymerized by TERP from the PVAc–TeMe macroinitiators leading to novel diblock copolymers that cannot be made by each technique used separately. [less ▲]

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See detailRheological characterization of double thermo-responsive block copolymer hydrogels
Thomassin, Jean-Michel ULg; Mathieu, Kevin ULg; Kermagoret, Anthony ULg et al

Poster (2013, November 20)

The ability of double thermoresponsive block copolymers to form hydrogels has been thoroughly studied by rheology. These copolymers having two discrete LCSTs were synthesized following a one-pot strategy ... [more ▼]

The ability of double thermoresponsive block copolymers to form hydrogels has been thoroughly studied by rheology. These copolymers having two discrete LCSTs were synthesized following a one-pot strategy based on the sequential cobalt mediated radical polymeryzation of N-vinylcaprolactam (NVCL) followed by the copolymerization of N-vinylpyrrolidone (NVP) with the residual NVCL.Moreover, the very efficient cobalt mediated radical coupling of the growing chains was advantageously used to design triblock copolymers with similar morphological characteristics than the diblock copolymers (same external block length, copolymer ratio…) allowing direct comparison between their respective gels to be established. Different parameters have been compared such as the block length and the copolymer concentration. Temperature ramps were first performed to distinguish the different states, i.e., solubilized copolymers (below the two LCSTs), micelles (between the two LCSTs) and precipitated polymers (above the two LCSTs). [less ▲]

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See detailDesign of well-defined N-vinylamides based copolymers via organometalllic-mediated radical polymerization
Debuigne, Antoine ULg; Kermagoret, Anthony ULg; Fustin, Charles-André et al

Conference (2013, June 19)

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See detailOne-pot controlled synthesis of double thermoresponsive N-vinylcaprolactam-based copolymers with tunable LCSTs
Kermagoret, Anthony ULg; Fustin, Charles-André; Bourguignon, Maxime et al

in Polymer Chemistry (2013), 4(8), 2575-2583

N-Vinylcaprolactam (NVCL) was copolymerized statistically for the first time in a controlled manner with hydrophilic N-vinylamide or hydrophobic vinylester monomers in order to precisely tune up and down ... [more ▼]

N-Vinylcaprolactam (NVCL) was copolymerized statistically for the first time in a controlled manner with hydrophilic N-vinylamide or hydrophobic vinylester monomers in order to precisely tune up and down the lower critical solution temperature (LCST) of the resulting copolymers. The incorporation of these segments in complex architectures was also considered. Several narrowly distributed NVCL-based copolymers were prepared by cobalt-mediated radical polymerization (CMRP) using the bis-(acetylacetonato)cobalt(II) complex as a controlling agent and N-methyl-N-vinylacetamide (NMVA), N-vinylacetamide (NVA), vinyl acetate (VAc) or vinyl pivalate (VPi) as comonomers. PNVCL-containing block copolymers having two discrete LCSTs were also synthesized following a one-pot strategy based on the sequential CMRP of NVCL followed by the copolymerization of NMVA with the residual NVCL. Upon gradual heating of aqueous solutions of such double thermoresponsive copolymers, we noticed a transition from free chains to micelles before full dehydration and collapse of the block copolymers. These advances represent a significant step towards the development of a platform based on thermoresponsive PNVCL copolymers with a single phase separation or multistep assembly behaviors. [less ▲]

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See detailOrganometallic-mediated radical polymerization of vinyl amides: Effect of metal coordination
Kermagoret, Anthony ULg; Morin, A.; Hurtgen, Marie ULg et al

Poster (2012, September 04)

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See detailOrganometallic-mediated radical polymerization of vinyl amides: Effect of metal coordination
Kermagoret, Anthony ULg; Morin, A.; Hurtgen, Marie ULg et al

Conference (2012, September 04)

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See detailSynthesis of novel poly(N-vinyl amide)s containing copolymers by cobalt-mediated radical polymerization
Kermagoret, Anthony ULg; Hurtgen, Marie ULg; Liu, Ji ULg et al

Poster (2012, May 10)

Poly(N-vinyl amide)s are found in many applications due to their valued properties including water solubility, biocompatibility, metal-coordination ability, etc. Although N-vinyl amides are easily ... [more ▼]

Poly(N-vinyl amide)s are found in many applications due to their valued properties including water solubility, biocompatibility, metal-coordination ability, etc. Although N-vinyl amides are easily polymerized via radical pathways, their growing radicals are quite reactive due to the lack of stabilizing group, rendering the synthesis of well-defined poly(N-vinyl amide)s challenging. Thus, we explored the organometallic-mediated radical polymerization (OMRP) of a series of N-vinyl amides using bis(acetylacetonato)cobalt(II) as controlling agent in order to develop a platform for the precision synthesis of poly(N-vinyl amide)s. [less ▲]

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See detailKey role of intramolecular metal chelation and hydrogen bonding in the cobalt-mediated radical polymerization of N-vinyl amides
Debuigne, Antoine ULg; Morin, Aurélie; Kermagoret, Anthony ULg et al

in Chemistry : A European Journal (2012), 18

This work reveals the preponderance of an intramolecular metal chelation phenomenon in a controlled radical polymerization system involving the reversible trapping of the radical chains by a cobalt ... [more ▼]

This work reveals the preponderance of an intramolecular metal chelation phenomenon in a controlled radical polymerization system involving the reversible trapping of the radical chains by a cobalt complex, i.e. the bis(acetylacetonato)cobalt(II). The cobalt-mediated radical polymerization (CMRP) of a series of N-vinyl amides was considered in order to evidence the effect of the cobalt chelation by the amide moiety of the last monomer unit of the chain. The latter reinforces the cobalt-polymer bond in the order N-vinylpyrrolidone < N-vinyl caprolactam < N-methyl-N-vinyl acetamide, and is responsible for the optimal control of the polymerizations observed for the last two monomers. Such a double linkage between the controlling agent and the polymer, via a covalent bond and a dative one, is unique in the field of controlled radical polymerization and represents a powerful opportunity to fine tune the equilibrium between latent and free radicals. The possible hydrogen bond formation is also taken into account in the case of N-vinyl acetamide and N-vinyl formamide. These results are essential for understanding factors influencing a Co-C bond strength in general, and the CMRP mechanism in particular, but also for developing a powerful platform for the synthesis of new precision poly(N-vinyl amide)s, an important class of polymers which sustains numerous applications today. [less ▲]

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