References of "Jérôme, Christine"
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See detailPEO coated magnetic nanoparticles for biomedical application
Aqil, Abdelhafid ULg; Vasseur, S.; Duguet, E. et al

in European Polymer Journal (2008), 44(10), 3191-3199

This paper reports on the preparation, characterization and stealthiness of superparamagnetic nanoparticles (magnetite Fe3O4) with a 5 nm diameter and stabilized in water (pH 6.5) by a shell of water ... [more ▼]

This paper reports on the preparation, characterization and stealthiness of superparamagnetic nanoparticles (magnetite Fe3O4) with a 5 nm diameter and stabilized in water (pH 6.5) by a shell of water-soluble poly(ethylene oxide) (PEO) chains. Two types of diblock copolymers, i.e., poly(acrylic acid)-b-poly(ethylene oxide), PAA–PEO, and poly(acrylic acid)-b-poly(acrylate methoxy poly(ethyleneoxide)), PAA–PAMPEO, were prepared as stabilizers with different compositions and molecular weights. At pH 6.5, the negatively ionized PAA block interacts strongly with the positively-charged nanoparticles, thus playing the role of an anchoring block. Aggregates of coated nanoparticles were actually observed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The hydrodynamic diameter was in the 50–100 nm range and the aggregation number (number of nanoparticles per aggregate) was lying between several tens and hundred. Moreover, the stealthiness of these aggregates was assessed “in vitro” by the hemolytic CH50 test. No response of the complement system was observed, such that biomedical applications can be envisioned for these magnetic nanoparticles. Preliminary experiments of magnetic heating (10 kA/m; 108 kHz) were performed and specific absorption rate varied from 2 to 13 W/g(Fe). [less ▲]

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See detailNovel pH responsive-copolymers for smart drug carriers
Jérôme, Christine ULg

Conference (2008, September 22)

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See detailRecent advances in the synthesis of aliphatic polyesters by “click” chemistry
Riva, Raphaël ULg; Jérôme, Christine ULg; Jérôme, Robert ULg et al

Conference (2008, September 11)

Since the discovery of Sharpless and Meldal, the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) is more and more popular in the field of macromolecular engineering owing to its robustness, its ... [more ▼]

Since the discovery of Sharpless and Meldal, the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) is more and more popular in the field of macromolecular engineering owing to its robustness, its high tolerance to a wide range of functional groups without any need of protecting groups and the absence of side-products. This reaction is known to be a very efficient “click” reaction as defined by Sharpless. The chemical modification of aliphatic polyesters remains, at the time being, a very difficult task to achieve because of the very limited number of efficient chemical reactions, which can be implemented in the absence of chain degradation. The main purpose of this contribution is to report on the most recent advances on the use of CuAAC to derivatize aliphatic polyesters (Scheme 1). Interestingly enough, it was recently shown that CuAAC carried out onto aliphatic polyesters attached with either azides or alkynes is very efficient under mild conditions, which limit undesirable degradation. Several functional groups were grafted onto aliphatic polyesters by CuAAC without using any protection/deprotection reactions. The CuAAC is also very efficient to prepare aliphatic polyesters with various architectures as highlighted by the synthesis of graft copolymers, star-shaped copolymers and networks. This “click” chemistry has been combined with other polymerization mechanism such as ATRP in order to extend further the range of available polymers. [less ▲]

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See detailMacromolecular engineering of aliphatic polyesters by ring-opening polymerization
Lecomte, Philippe ULg; Jérôme, Christine ULg; Jérôme, Robert ULg

Conference (2008, September 09)

During the past few years, a steadily increasing attention was paid to the synthesis of biodegradable and biocompatible aliphatic polyesters because of potential applications as biomaterials or as ... [more ▼]

During the past few years, a steadily increasing attention was paid to the synthesis of biodegradable and biocompatible aliphatic polyesters because of potential applications as biomaterials or as environmentally friendly thermoplastics. The first purpose of this work is to show that the modification of these aliphatic polyesters by pendant functional groups is an efficient tool to tailor the main properties, including biodegradation rate, bioadhesion, hydrophilicity, degree of crystallinity. The strategies implemented for the synthesis of aliphatic polyesters bearing pendant functional groups rely on the synthesis of g-substituted e-caprolactones followed by their ring-opening polymerization and on the chemical modification of duly functionalized aliphatic polyesters.The second part of the lecture will be dedicated to some recent examples dealing with the use of functional caprolactones to prepare various architectures such as star-shaped copolymers, graft copolymers, macrocycles and networks. [less ▲]

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See detailFunctional nanoobjects by means of polymers
Van Butsele, Kathy; Aqil, Abdelhafid ULg; Jérôme, Christine ULg

Conference (2008, September 08)

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See detailTemperature responsive complex coacervate core micelles with a PEO and PNIPAAm corona
Voets, Ilya K.; Moll, Puck M.; Aqil, Abdelhafid et al

in Journal of Physical Chemistry B (2008), 112(35), 10833-10840

In aqueous solutions at room temperature, poly(N-methyl-2-vinyl pyridinium iodide)-block-poly(ethylene oxide), P2MVP38-b-PEO211 and poly(acrylic acid)-block-poly(isopropyl acrylamide), PAA55-b-PNIPAAm88 ... [more ▼]

In aqueous solutions at room temperature, poly(N-methyl-2-vinyl pyridinium iodide)-block-poly(ethylene oxide), P2MVP38-b-PEO211 and poly(acrylic acid)-block-poly(isopropyl acrylamide), PAA55-b-PNIPAAm88 spontaneously coassemble into micelles, consisting of a mixed P2MVP/PAA polyelectrolyte core and a PEO/PNIPAAm corona. These so-called complex coacervate core micelles (C3Ms), also known as polyion complex (PIC) micelles, block ionomer complexes (BIC), and interpolyelectrolyte complexes (IPEC), respond to changes in solution pH and ionic strength as their micellization is electrostatically driven. Furthermore, the PNIPAAm segments ensure temperature responsiveness as they exhibit lower critical solution temperature (LCST) behavior. Light scattering, two-dimensional 1H NMR nuclear Overhauser effect spectrometry, and cryogenic transmission electron microscopy experiments were carried out to investigate micellar structure and solution behavior at 1 mM NaNO3, T = 25, and 60 °C, that is, below and above the LCST of 32 °C. At T = 25 °C, C3Ms were observed for 7 < pH < 12 and NaNO3 concentrations below 105 mM. The PEO and PNIPAAm chains appear to be (randomly) mixed within the micellar corona. At T = 60 °C, onion-like complexes are formed, consisting of a PNIPAAm inner core, a mixed P2MVP/PAA complex coacervate shell, and a PEO corona. [less ▲]

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See detailJoint theoretical experimental investigation of the electron spin resonance spectra of nitroxyl radicals: application to intermediates in in situ nitroxide mediated polymerization (in situ NMP) of vinyl monomers
Zarycz, Natalia; Botek, Edith; Champagne, Benoit et al

in Journal of Physical Chemistry B (2008), 112(34), 10432-10442

Density functional theory (DFT) calculations have been performed to address the structure of nitroxide intermediates in controlled radical polymerization. In a preliminary step, the reliability of ... [more ▼]

Density functional theory (DFT) calculations have been performed to address the structure of nitroxide intermediates in controlled radical polymerization. In a preliminary step, the reliability of different theoretical methods has been substantiated by comparing calculated hyperfine coupling constants (HFCCs) to experimental data for a set of linear and cyclic alkylnitroxyl radicals. Considering this tested approach, the nature of different nitroxides has been predicted or confirmed for (a) the reaction of C-phenyl-N-tert-butylnitrone and AIBN, (b) N-tert-butyl-α-isopropylnitrone and benzoyl peroxide, (c) tert-butyl methacrylate polymerization in the presence of sodium nitrite as mediator, and (d) for the reaction of a nitroso compound with AIBN. Values of HFCC experimentally determined have been confirmed by DFT calculations. [less ▲]

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See detailCobalt-mediated radical polymerization of acrylonitrile: Kinetics investigations and DFT calculations
Debuigne, Antoine ULg; Michaux, Catherine; Jérôme, Christine ULg et al

in Chemistry : A European Journal (2008), 14(25), 7623-7637

The successful controlled homopolymerization of acrylonitrile (AN) by cobalt-mediated radical polymerization (CMRP) is reported for the first time. As a rule, initiation of the polymerization was carried ... [more ▼]

The successful controlled homopolymerization of acrylonitrile (AN) by cobalt-mediated radical polymerization (CMRP) is reported for the first time. As a rule, initiation of the polymerization was carried out starting from a conventional azo-initiator (V-70) in the presence of bis(acetylacetonato)cobalt(II) ([Co(acac)2]) but also by using organocobalt(III) adducts. Molar concentration ratios of the reactants, the temperature, and the solvent were tuned, and the effect of these parameters on the course of the polymerization is discussed in detail. The best level of control was observed when the AN polymerization was initiated by an organocobalt(III) adduct at 0 °C in dimethyl sulfoxide. Under these conditions, poly(acrylonitrile) with a predictable molar mass and molar mass distribution as low as 1.1 was prepared. A combination of kinetic data, X-ray analyses, and DFT calculations were used to rationalize the results and to draw conclusions on the key role played by the solvent molecules in the process. These important mechanistic insights also permit an explanation of the unexpected solvent effect that allows the preparation of well-defined poly(vinyl acetate)-b-poly(acrylonitrile) by CMRP. [less ▲]

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See detailSynthesis of PCL/clay masterbatches in supercritical carbon dioxide
Urbanczyk, Laetitia ULg; Calberg, Cédric ULg; Stassin, Fabrice et al

in Polymer (2008), 49(18), 3979-3986

Pre-exfoliated nanoclays were prepared through a masterbatch process using supercritical carbon dioxide as solvent and poly(epsilon-caprolactone) as organic matrix. In situ polymerization of epsilon ... [more ▼]

Pre-exfoliated nanoclays were prepared through a masterbatch process using supercritical carbon dioxide as solvent and poly(epsilon-caprolactone) as organic matrix. In situ polymerization of epsilon-caprolactone in the presence of large amount of clay was conducted to obtain these easily dispersible nanoclays, collected as a dry and fine powder after reaction. Dispersion of these pre-exfoliated nanoclays in chlorinated polyethylene was also investigated. All the results confirm the specific advantages of supercritical CO2 towards conventional solvents for filler modification. [less ▲]

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See detailA generic chemical platform for molecular recognition and stimuli-responsive probes based on scanning probe microscopy
Cecchet, Francesca; Lussis, Perrine ULg; Jérôme, Christine ULg et al

in Small : Nano Micro (2008), 4(8), 1101-1104

The grafting of poly-N-succinimidyl acrylate from scanning probe microscopy tips is shown to be a robust platform for the very easy elaboration of versatile probes with sensor capabilities and tunable ... [more ▼]

The grafting of poly-N-succinimidyl acrylate from scanning probe microscopy tips is shown to be a robust platform for the very easy elaboration of versatile probes with sensor capabilities and tunable properties. The modified tips can be easily postfunctionalized for single-molecule recognition of host-guest and ligand-receptor systems and for the design of smart probes that are thermo- and pH-responsive. [less ▲]

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See detailPoly(caprolactone)/clay masterbatches prepared in supercritical CO2 as efficient clay delamination promoters in poly(styrene-co-acrylonitrile)
Urbanczyk, Laetitia ULg; Calberg, Cédric ULg; Benali, Samira et al

in Journal of Materials Chemistry (2008), 18(39), 4623-4630

Poly(styrene-co-acrylonitrile) (SAN)/clay nanocomposites with a high degree of clay exfoliation were prepared upon melt blending of pre-exfoliated poly(-caprolactone) (PCL)/organoclay masterbatches in a ... [more ▼]

Poly(styrene-co-acrylonitrile) (SAN)/clay nanocomposites with a high degree of clay exfoliation were prepared upon melt blending of pre-exfoliated poly(-caprolactone) (PCL)/organoclay masterbatches in a Brabender-type internal mixer. These highly filled masterbatches were synthesized by a one-pot process using supercritical carbon dioxide as a polymerization medium. During their dispersion into SAN, PCL is expected to act as a compatibilizer at the polymer–clay interface as it is miscible with the host matrix under these conditions. Reference nanocomposites based on direct melt mixing of the commercial organoclay were also prepared for the sake of comparison. The superiority of the masterbatch route in term of clay delamination efficiency has been evidenced by XRD analysis, visual and TEM observations. The effect of the nanocomposite morphology on the polymer properties was then investigated. A substantial improvement of the fire behaviour and a decrease in gas permeability have been observed for the nanocomposite containing the highest level of clay exfoliation, accompanied with a higher brittleness as evidenced by traction and impact tests. [less ▲]

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