References of "Debuigne, Antoine"
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See detailDouble hydrophilic polyphosphoester containing copolymers as efficient templating agents for calcium carbonate microparticles
Ergül, Zeynep ULg; Debuigne, Antoine ULg; Calvignac, Brice et al

in Journal of Materials Chemistry B (in press)

The use of calcium carbonate (CaCO3) microparticles is becoming more and more attractive in many fields especially in biomedical applications in which the fine tuning of the size, morphology and ... [more ▼]

The use of calcium carbonate (CaCO3) microparticles is becoming more and more attractive in many fields especially in biomedical applications in which the fine tuning of the size, morphology and crystalline form of the CaCO3 particles is crucial. Although some structuring compounds, like hyaluronic acid, give satisfying results, the control of the particle structure still has to be improved. To this end, we evaluated the CaCO3 structuring capacity of novel well-defined double hydrophilic block copolymers composed of poly(ethylene oxide) and a polyphosphoester segment with an affinity for calcium like poly(phosphotriester)s bearing pendent carboxylic acids or poly(phosphodiester)s with a negatively charged oxygen atom on each repeating monomer unit. These copolymers were synthesized by a combination of organocatalyzed ring opening polymerization, thiol–yne click chemistry and protection/deprotection methods. The formulation of CaCO3 particles was then performed in the presence of these block copolymers (i) by the classical chemical pathway involving CaCl2 and Na2CO3 and (ii) by a process based on supercritical carbon dioxide (scCO2) technology in which CO32− ions are generated in aqueous media and react with Ca2+ ions. Porous CaCO3 microspheres composed of vaterite nanocrystals were obtained. Moreover, a clear dependence of the particle size on the structure of the templating agent was emphasized. In this work, we show that the use of the supercritical process and the substitution of hyaluronic acid for a carboxylic acid containing copolymer decreases the size of the CaCO3 particles by a factor of 6 (∼1.5 μm) while preventing their aggregation. [less ▲]

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See detailHalomethyl-cobalt(bis-acetylacetonate) for the controlled synthesis of functional polymers
Demarteau, Jérémy ULg; Kermagoret, Anthony; German, Ian et al

in Chemical Communications (in press)

Novel organocobalt complexes featuring weak C–CoL2 bonds (L = acetylacetonate) are prepared and used as sources of halomethyl radicals. They permit the precision synthesis of a-halide functionalized and ... [more ▼]

Novel organocobalt complexes featuring weak C–CoL2 bonds (L = acetylacetonate) are prepared and used as sources of halomethyl radicals. They permit the precision synthesis of a-halide functionalized and telechelic polymers in organic media or in water. Substitution of halide by azide allows derivatization of polymers using the CuAAC click reaction. [less ▲]

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See detailAll Poly(ionic liquid)-based block copolymers by sequential controlled radical copolymerization of vinylimidazolium monomers
Cordella, Daniela ULg; Kermagoret, Anthony; Debuigne, Antoine ULg et al

in Macromolecules (2015), 48(15), 5230-5243

The organometallic-mediated radical polymerization (OMRP) of N-vinyl-3-alkylimidazolium-type monomers, featuring the bis(trifluoromethylsulfonyl)imide counteranion (Tf2N–), in the presence of Co(acac)2 as ... [more ▼]

The organometallic-mediated radical polymerization (OMRP) of N-vinyl-3-alkylimidazolium-type monomers, featuring the bis(trifluoromethylsulfonyl)imide counteranion (Tf2N–), in the presence of Co(acac)2 as controlling agent, is reported. Polymerizations of monomers with methyl, ethyl, and butyl substituents are fast, reaching high monomer conversion in ethyl acetate as solvent at 30 °C, and afford structurally well-defined hydrophobic poly(ionic liquid)s (PILs) of N-vinyl type. Block copolymer synthesis is also achieved by sequential OMRP of N-vinyl-3-alkylimidazolium salts carrying different alkyl chains and different counteranions (Tf2N– or Br–). These block copolymerizations are carried out at 30 °C, either under homogeneous solution in methanol or in a biphasic medium consisting of a mixture of ethyl acetate and water. Unprecedented PIL-b-PIL block copolymers are thus prepared under these conditions. However, anion exchange occurs at the early stage of the growth of the second block. Finally, diblock copolymers generated in the biphasic medium can be readily coupled by addition of isoprene, forming all PIL-based and symmetrical ABA-type triblock copolymers in a one-pot process. Such a direct block copolymerization method, involving vinylimidazolium monomers bearing different alkyl chains, thus opens new opportunities in the precision synthesis of all PIL-based block copolymers of tunable properties. [less ▲]

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See detailDouble hydrophilic polyphosphoester containing copolymers as efficient templating agnets for calcium carbonate microparticles
Ergül, Zeynep ULg; Debuigne, Antoine ULg; Calvignac, Brice et al

Conference (2015, June 22)

The design of drug delivery systems (DDS) often requires biodegradable and biocompatible materials that allow safe retention and controlled drug release. In this respect, CaCO3 particles are appropriate ... [more ▼]

The design of drug delivery systems (DDS) often requires biodegradable and biocompatible materials that allow safe retention and controlled drug release. In this respect, CaCO3 particles are appropriate drug carriers that have excellent properties such as low density, high specific surface areas and porosity for drugs and proteins encapsulation. Here, degradable synthetic copolymers based on polyphosphoester (PPE) were used to template CaCO3 particles. PPE is a promising candidate due to its biocompatibility, biodegradability and low toxicity of its degradation products such as phosphates. In particular, PPE copolymers with carboxylic acid pendant groups and negatively charged polyphosphodiester-based copolymers were prepared by organocatalyzed ring opening polymerization (ROP) initiated from poly(ethylene oxide). The moieties introduced along the polymer chains enhance the calcium affinity and so the ability of the copolymers to tune the morphology of the CaCO3 particles. The copolymers were tested as templating agents for the preparation of CaCO3 particles by the classical chemical pathway and the supercritical CO2 (Sc-CO2) route. The morphology of the resulting particles was then compared to the one of particles obtained using hyaluronic acid (HA) as a templating agent. The synthesis involving Sc-CO2 and the copolymer with pendant carboxylic groups was particularly interesting and led to smaller (~1.5 µm) and non-aggregated particles. In the future, the impact of the copolymer structure and of the particle size on the encapsulation and release processes will be investigated. [less ▲]

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See detailOrganometallic-mediated radical synthesis of well-defined ethylene-vinyl acetate statistical and block copolymers
Demarteau, Jérémy ULg; Kermagoret, Anthony; Jérôme, Christine ULg et al

Poster (2015, May 18)

The copolymerization of ethylene (E) and vinyl acetate (VAc) is of high interest for polymer industry. Nevertheless, the control of the macromolecular parameters of ethylene-vinyl acetate copolymers (EVAs ... [more ▼]

The copolymerization of ethylene (E) and vinyl acetate (VAc) is of high interest for polymer industry. Nevertheless, the control of the macromolecular parameters of ethylene-vinyl acetate copolymers (EVAs) is difficult to achieve. Herein, we report the controlled radical copolymerization of these monomers by organometallic-mediated radical polymerization (OMRP) using Co(acac)2 as controlling agent. The ethylene pressure is varied from 10 to 100 bar and we discuss the effect of this parameter on kinetics, level of control and copolymer composition. EVAs are synthetized accordingly with low dispersities and ethylene content reaches up to 57 mol%. The precision design of EVA-containing block copolymers, i.e. PVAc-block-EVA, is also addressed. [less ▲]

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See detailA tool for the precision synthesis of poly(ionic liquid)s in water
Cordella, Daniela ULg; Kermagoret, Anthony; Debuigne, Antoine ULg et al

Conference (2015, May 18)

In recent years, poly(ionic liquid)s (PIL)s were found to take an enabling role in important fields of polymer chemistry and material science. PILs combine the unique properties of ionic liquids with the ... [more ▼]

In recent years, poly(ionic liquid)s (PIL)s were found to take an enabling role in important fields of polymer chemistry and material science. PILs combine the unique properties of ionic liquids with the flexibility and properties of macromolecular architectures giving rise to a new family of functional polymers that opens new area of applications such as polymer electrolytes in electrochemical devices, powerful dispersants and stabilizers, absorbing membranes, precursors for carbon materials, porous polymers, etc. In this communication, we will report on the implementation of organometallic-mediated radical polymerization (OMRP) technique for the precision synthesis of unprecedented PILs (co)polymers. We will discuss how an organocobalt complex can efficiently control the growth of vinyl imidazolium chains and lead to PILs with predicted molar masses and low polydispersities under mild experimental conditions, which provide low temperatures (compared to the conventional radical polymerization techniques) and also the use of water as green polymerization medium. The huge potential of this system will be also highlighted by describing the one-pot synthesis of vinyl imidazolium-based block copolymers in heterogeneous conditions. This OMRP is unique for providing well-defined vinyl imidazolium based-copolymers opening for advanced PILs applications. [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 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 detailPoly(vinyl ester 1,2,3-triazolium)s: a new member of the poly(ionic liquid)s family
Obadia, M. M.; Colliat-Dangus, G.; Debuigne, Antoine ULg et al

in Chemical Communications (2015), 51(16), 3332-3335

A vinyl ester monomer carrying a pendant 1,2,3-triazole group is synthesized in two steps and polymerized by cobalt-mediated radical polymerization. Subsequent alkylation with N-methyl bis ... [more ▼]

A vinyl ester monomer carrying a pendant 1,2,3-triazole group is synthesized in two steps and polymerized by cobalt-mediated radical polymerization. Subsequent alkylation with N-methyl bis[(trifluoromethyl)sulfonyl]imide affords the corresponding poly(vinyl ester 1,2,3-triazolium). This unprecedented example of poly(vinyl ester ionic liquid) exhibits an ionic conductivity of 9.2 × 10(-7) S cm(-1) at 30 °C [less ▲]

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See detailStimuli-responsive behavior of micelles prepared from a poly(vinyl alcohol)-block-poly(acrylic acid)-block-poly(4-vinylpyridine) triblock terpolymer
Poggi, Elio; Guerlain, Claire; Debuigne, Antoine ULg et al

in European Polymer Journal (2015), 62

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 ... [more ▼]

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. [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 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 detailDirect route to well-defined poly(ionic liquid)s by controlled radical polymerization in water
Cordella, Daniela ULg; Kermagoret, Anthony ULg; Debuigne, Antoine ULg et al

in ACS Macro Letters (2014), 3

The precision synthesis of poly(ionic liquid)s (PILs) in water is achieved for the first time by the cobalt-mediated radical polymerization (CMRP) of N-vinyl-3-alkylimidazolium-type monomers following two ... [more ▼]

The precision synthesis of poly(ionic liquid)s (PILs) in water is achieved for the first time by the cobalt-mediated radical polymerization (CMRP) of N-vinyl-3-alkylimidazolium-type monomers following two distinct protocols. The first involves the CMRP of various 1-vinyl-3-alkylimidazolium bromides conducted in water in the presence of an alkyl–cobalt(III) complex acting as a monocomponent initiator and mediating agent. Excellent control over molar mass and dispersity is achieved at 30 °C. Polymerizations are complete in a few hours, and PIL chain-end fidelity is demonstrated up to high monomer conversions. The second route uses the commercially available bis(acetylacetonato)cobalt(II) (Co(acac)2) in conjunction with a simple hydroperoxide initiator (tert-butyl hydroperoxide) at 30, 40, and 50 °C in water, facilitating the scaling-up of the technology. Both routes prove robust and straightforward, opening new perspectives onto the tailored synthesis of PILs under mild experimental conditions in water. [less ▲]

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