References of "Detrembleur, Christophe"
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See detailStimuli-responsive magnetic nanohybrids designed for controlled drug release application
Liu, Ji ULg; Detrembleur, Christophe ULg; Mornet, Stephan et al

Conference (2012, May 10)

Stimuli-responsive organic/inorganic nanohybrids, with an inorganic core and a polymer coating, have been frequently suggested as a promising vehicle for drug or gene delivery and also controlled release ... [more ▼]

Stimuli-responsive organic/inorganic nanohybrids, with an inorganic core and a polymer coating, have been frequently suggested as a promising vehicle for drug or gene delivery and also controlled release, due to their outstanding biocompatibility, versatile surface modification, specific responsive properties to external stimuli, and so on. Magnetic nanoparticles have various applications in biomedical filed, such as magnetic resonance imaging, biosensors, magnetic separation, drug release, hyperthermia therapy and so on. Poly (acrylic acid) copolymers exhibit a sharp conformation transition when exposed to external change in pH. The PAA copolymer was used to form a polymer shell outside the magnetic core, a cationic dye was uploaded by electro-static interaction. The controlled release was achieved by tuning the external pH value. Magnetic/SiO2 mesoporous nanoparticles were prepared as another drug vehicle, in order to obtain a higher drug loading amount. Crystalline molecules were utilized as a gate keeper to control the release of drugs uploaded. [less ▲]

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See detailAntibacterial polyelectrolyte micelles for coating stainless steel
Falentin, Céline ULg; Faure, Emilie ULg; Svaldo Lanero, Tiziana ULg et al

in Langmuir (2012), 28(18), 7233-7241

In this study, we report on the original synthesis and characterization of novel antimicrobial coatings for stainless steel by alternating the deposition of aqueous solutions of positively charged ... [more ▼]

In this study, we report on the original synthesis and characterization of novel antimicrobial coatings for stainless steel by alternating the deposition of aqueous solutions of positively charged polyelectrolytes micelles doped with silver based nanoparticles with a polyanion. The micelles are formed by electrostatic interaction between two oppositely charged polymers, a polycation bearing 3,4-dihydroxyphenylalanine units (DOPA, a major component of natural adhesives) and a polyanion (poly(styrene sulfonate), PSS) without using any block copolymer. DOPA units are exploited for their well-known ability to anchor to stainless steel and to form and stabilize biocidal silver nanoparticles (Ag0). The chlorine counter-anion of the polycation forms and stabilizes biocidal silver chloride nanoparticles (AgCl). We demonstrate that two layers of micelles (alternated by PSS) doped by silver particles are enough to impart to the surface a strong antibacterial activity against Gram-negative E. coli. Moreover, micelles that are reservoirs of biocidal Ag+ can be easily reactivated after depletion. This novel water-based approach is convenient, simple and attractive for industrial applications. [less ▲]

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See detailMolecular biomimetics applied to medical devices
Van de Weerdt, Cécile ULg; Archembeau, Catherine; Vreuls, Christelle ULg et al

Poster (2012, May 05)

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See detailNanoporous thin films from ionically connected diblock copolymers
Yu, Haizhou; Stoffelbach, François; Detrembleur, Christophe ULg et al

in European Polymer Journal (2012), 48(5), 940-944

An ionically connected polystyrene-block-poly(ethylene oxide) diblock copolymer (PS−+PEO) has been prepared by blending a PEO block functionalized by a dimethylamino group at one extremity with a sulfonic ... [more ▼]

An ionically connected polystyrene-block-poly(ethylene oxide) diblock copolymer (PS−+PEO) has been prepared by blending a PEO block functionalized by a dimethylamino group at one extremity with a sulfonic acid terminated PS block. Proton transfer occurs from the sulfonic acid to the dimethylamino group, resulting in the formation of an ion pair acting as a junction between the two polymer blocks. This copolymer was further used to prepare thin films with a cylindrical morphology consisting of PEO cylinders embedded in a PS matrix and oriented perpendicularly to the film surface. Nanoporous thin films with sulfonate groups on the pore walls have been finally obtained after solvent extraction of the PEO microphases. The presence of those sulfonate groups was evidenced by grafting a positively charged fluorescent dye on the pore walls. [less ▲]

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See detailBiomolecule-based antibacterial coating on a stainless steel surface: multilayer film build-up optimization and stability study.
Vreuls, Christelle ULg; Zocchi, Germaine ULg; Vandegaart, Hélène ULg et al

in Biofouling (2012), 28(4), 395-404

The goal of this paper was to establish the durability profile of antibacterial multilayer thin films under storage and usage conditions. Thin films were built on stainless steel (SS) by means of a layer ... [more ▼]

The goal of this paper was to establish the durability profile of antibacterial multilayer thin films under storage and usage conditions. Thin films were built on stainless steel (SS) by means of a layer-by-layer process alternating a negatively charged polyelectrolyte, polyacrylic acid, with a cationic antibacterial peptide, nisin. SS coupons coated with the antibacterial film were challenged under environmental and usage conditions likely to be encountered in real-world applications. The change in antibacterial activity elicited by the challenge was used as an indicator of multilayer film resistance. Antibacterial SS samples could be stored for several weeks at 4°C in ambient air and antibacterial films were resistant to dipping and mild wiping in water and neutral detergent. The multilayer coating showed some weaknesses, however, that need to be addressed. [less ▲]

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See detailInnovative multilayered nanofibers for wound dressing application
Croisier, Florence ULg; Detrembleur, Christophe ULg; Jérôme, Christine ULg

Poster (2012, April 18)

Chitosan is a natural polymer derived from the chitin of crustacean or mushroom shells, that intrinsically presents haemostatic, mucoadhesive, antimicrobial and immunostimulant properties. This ... [more ▼]

Chitosan is a natural polymer derived from the chitin of crustacean or mushroom shells, that intrinsically presents haemostatic, mucoadhesive, antimicrobial and immunostimulant properties. This polysaccharide has shown a great potential for biomedical and pharmaceutical applications, on account of its remarkable compatibility with physiological medium. Besides, it is degraded in a physiological environment into non-toxic products, which make chitosan an outstanding candidate for short- to medium-term applications. In this respect, nanometric fibers are highly interesting as their assembly mimics the skin extracellular matrix structure. Such nanofibrous materials can be prepared by electrospinning (ESP). This technique uses a high voltage to create an electrically charged jet of polymer solution or melt which leads to fibers formation. Depending on the polymer characteristics (a.o. molecular weight, solution viscosity and conductivity) and processing conditions (electric potential, distance between syringe-capillary and collection plate, concentration, flow rate), polymer fibers ranging from nanometers to a few microns in diameter can be obtained and subsequently used as potential scaffolds, a.o. to form a temporary, artificial extracellular matrix. In the present study, electrospinning technique was combined with layer-by-layer deposition method (LBL) - a well-known method for surface coating, based on electrostatic interactions - in order to prepare multilayered chitosan-based nanofibers. The antibacterial properties of the obtained material were then assessed, and the presence of a multilayered deposit was confirmed by several techniques. (Future) possibilities for valorization: These multilayered chitosan-based nanofibers present great prospects for the preparation of new biomedical scaffolds - such as wound dressings that could improve skin regeneration. [less ▲]

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See detailMolecular biomimetics applied to medical devices
Van de Weerdt, Cécile ULg; Vreuls, Christelle ULg; Genin, Alexis ULg et al

Poster (2012, April 18)

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See detailMicrostructure characterisation of nanocomposite polymeric foams by X-ray microtomography
Plougonven, Erwan ULg; Detrembleur, Christophe ULg; Tran, Minh Phuong ULg et al

Poster (2012, March 26)

Recent advances in microstructured materials have given rise to many new types of composites that exhibit original and interesting physical properties. For example, a nanocomposite made of carbon ... [more ▼]

Recent advances in microstructured materials have given rise to many new types of composites that exhibit original and interesting physical properties. For example, a nanocomposite made of carbon nanotubes inside a polymer matrix shows exceptional electromagnetic interference shielding effectiveness when foamed. However, the effective properties of such materials strongly depend on the shape and topology of the microstructural cells. An accurate method for investigating the cellular microstructure is X-ray microtomography (XRμT), for it is non-destructive, and it provides 3D geometric information. Although it cannot be used to observe nanofiller dispersion, it has a strong potential for cell structure characterisation. In order to reduce the need for trial and error in tailoring these materials, our objective is to quantify, using XRμT, cellular microstructure, for two different types of foaming procedures, namely supercritical CO2 batch foaming and freeze drying, to be able to establish a link between the structure and its shielding effectiveness. The main difficulty stems from the type of material being studied: it is light, therefore hardly absorbs X-rays, cell size is small compared to the resolution capacity of the tomograph, and cell wall thickness is extremely thin in some cases, making them very hard to discern in the images. For these reasons, common image analysis tools for identifying and delimiting objects in an image prove impractical. We propose an original method that uses the 3D autocorrelation function of the tomograms to determine statistical information from these images, such as average cell size and anisotropy, without the need to binarise and segment the images. [less ▲]

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See detailRadical coupling of polymers formed by cobalt-mediated radical polymerization
Debuigne, Antoine ULg; Hurtgen, Marie ULg; Jérôme, Christine ULg et al

in Matyjaszewski, Krzysztof; Sumerlin, Brent; Tsarevsky, Nicolas V. (Eds.) Progress in controlled radical polymerization: mechanisms and techniques (2012)

Considerable progress has been recently made in cobalt-mediated radical polymerization (CMRP), a controlled radical polymerization system based on the temporary deactivation of the polymer chains by a ... [more ▼]

Considerable progress has been recently made in cobalt-mediated radical polymerization (CMRP), a controlled radical polymerization system based on the temporary deactivation of the polymer chains by a cobalt complex, like the improvement of the mechanistic understanding, the extension to a range of monomers and the preparation of novel architectures. However, the real breakthrough in this field concerns the development of efficient radical coupling methods for polymer precursors preformed by CMRP. This book chapter aims to describe the general principle and main characteristics of such radical coupling techniques involving dienes, nitrones, fullerenes or carbon nanotubes. Well-defined and complex architectures obtained by these techniques are provided in order to illustrate their potential for macromolecular engineering. [less ▲]

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See detailHybrid material for electromagnetic absorption
Detrembleur, Christophe ULg; Molenberg, Isabel; Huynen, Isabelle et al

Patent (2012)

The present invention relates to a hybrid material (10) for absorbing electromagnetic radiation (60) and a method for making such a material. The hybrid material (10) comprises at least one grid panel (20 ... [more ▼]

The present invention relates to a hybrid material (10) for absorbing electromagnetic radiation (60) and a method for making such a material. The hybrid material (10) comprises at least one grid panel (20) of thickness t 1 having holes (25) traversing said thickness t 1 , at least one polymer composite material (30) of thickness t 2 filling at least partially the holes (25) of the at least one grid panel (20), said at least one polymer composite material (30) including a polymer matrix (40) and conductive particles (50) dispersed into said polymer matrix (40), characterized in that the internal surface of the holes (25) of the at least one grid panel (20) is metallic. [less ▲]

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See detailHybrid material for electromagnetic absorption
Detrembleur, Christophe ULg; Huynen, Isabelle; Thomassin, Jean-Michel ULg et al

Patent (2012)

The present invention relates to a hybrid material (10) for absorbing electromagnetic radiation (60) and a method for making such a material. The hybrid material (10) comprises at least one grid panel (20 ... [more ▼]

The present invention relates to a hybrid material (10) for absorbing electromagnetic radiation (60) and a method for making such a material. The hybrid material (10) comprises at least one grid panel (20) of thickness t 1 having holes (25) traversing said thickness t 1 , at least one polymer composite material (30) of thickness t 2 filling at least partially the holes (25) of the at least one grid panel (20), said at least one polymer composite material (30) including a polymer matrix (40) and conductive particles (50) dispersed into said polymer matrix (40), characterized in that the internal surface of the holes (25) of the at least one grid panel (20) is metallic. [less ▲]

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See detailProcess for preparing electromagnetic interference shileding materials
Thomassin, Jean-Michel ULg; Jérôme, Christine ULg; Detrembleur, Christophe ULg et al

Patent (2012)

The present invention relates to a process for preparing an electromagnetic interference shielding material, or a precursor thereof, comprising a first polymer matrix and carbon conductive loads, said ... [more ▼]

The present invention relates to a process for preparing an electromagnetic interference shielding material, or a precursor thereof, comprising a first polymer matrix and carbon conductive loads, said process comprises the steps of: (a) Forming a reaction mixture comprising carbon conductive loads and a polymerizable medium said polymerizable medium comprising one or more monomers dissolved in a solvent, (b) Exposing the reaction mixture to polymerization conditions to polymerize said polymerizable medium and thus form a polymer, and (c) Forming a precipitate or an agglomerate of an electromagnetic interference shielding material made of less than 50 wt.% carbon conductive loads dispersed in the first polymer matrix formed in step (b), characterized in that, said polymer is insoluble in said solvent and in that a fraction of the polymer chains thus formed are grafted on part of the surface of the carbon conductive loads. [less ▲]

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See detailProcess for preparing electromagnetic interference shileding materials
Thomassin, Jean-Michel ULg; Jérôme, Christine ULg; Detrembleur, Christophe ULg et al

Patent (2012)

The present invention relates to a process for preparing an electromagnetic interference shielding material, or a precursor thereof, comprising a first polymer matrix and carbon conductive loads, said ... [more ▼]

The present invention relates to a process for preparing an electromagnetic interference shielding material, or a precursor thereof, comprising a first polymer matrix and carbon conductive loads, said process comprises the steps of: (a) Forming a reaction mixture comprising carbon conductive loads and a polymerizable medium said polymerizable medium comprising one or more monomers dissolved in a solvent, (b) Exposing the reaction mixture to polymerization conditions to polymerize said polymerizable medium and thus form a polymer, and (c) Forming a precipitate or an agglomerate of an electromagnetic interference shielding material made of less than 50 wt.% carbon conductive loads dispersed in the first polymer matrix formed in step (b), characterized in that, said polymer is insoluble in said solvent and in that a fraction of the polymer chains thus formed are grafted on part of the surface of the carbon conductive loads. [less ▲]

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See detailClay and DOPA containing polyelectrolyte multilayer film for imparting anticorrosion properties to galvanized steel
Faure, Emilie ULg; Halusiak, Emilie; Farina, Fabrice et al

in Langmuir (2012), 28(5), 2971-2978

A facile and green approach is developed to impart remarkable protection against corrosion to galvanized steel. A protecting multilayer film is formed by alternating the deposition of a polycation bearing ... [more ▼]

A facile and green approach is developed to impart remarkable protection against corrosion to galvanized steel. A protecting multilayer film is formed by alternating the deposition of a polycation bearing catechol groups, used as corrosion inhibitors, with clay that induces barrier properties. This coating does not affect the esthetical aspect of the surface and does not release any toxic molecules in the environment. [less ▲]

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See detailElectromagnetic absorption properties of carbon nanotube nanocomposite foam filling honeycomb waveguide structures
Quiévy, Nicolas; Bollen, Pierre; Thomassin, Jean-Michel ULg et al

in IEEE Transactions on Electromagnetic Compatibility (2012), 24(1), 43-51

Carbon nanotube reinforced polymer foams filling a metallic honeycomb were processed and characterized for the production of hybrid materials with high electromagnetic absorption potential ... [more ▼]

Carbon nanotube reinforced polymer foams filling a metallic honeycomb were processed and characterized for the production of hybrid materials with high electromagnetic absorption potential. Electromagnetic modeling and experimental characterization of the hybrids proved that the honeycomb, acting as a hexagonal waveguide, improves the absorption properties in the gigahertz range above the cutoff frequency. The electromagnetic absorption can be tuned by changing the hybrid material properties. The required levels of electrical conductivity are attained owing to the dispersion of low amounts (1–2 wt%) of carbon nanotubes inside the polymermatrix. The combination of the foam and honeycomb architecture contributes to decrease the real part of the relative effective permittivity Re{εr,eff }. Varying the cell shape of the honeycomb changes the frequency range for high absorption. An analytical model for the absorption has been developed, showing good agreement with the experimental results. [less ▲]

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See detailSynthesis of thermo-responsive poly(N-vinylcaprolactam)-containing block copolymers by cobalt-mediated radical polymerization
Hurtgen, Marie ULg; Liu, Ji ULg; Debuigne, Antoine ULg et al

in Journal of Polymer Science. Part A, Polymer Chemistry (2012), 50(2), 400-408

Thermo-responsive block copolymers based on poly(N-vinylcaprolactam) (PNVCL) have been prepared by cobalt-mediated radical polymerization (CMRP) for the first time. The homopolymerization of NVCL was ... [more ▼]

Thermo-responsive block copolymers based on poly(N-vinylcaprolactam) (PNVCL) have been prepared by cobalt-mediated radical polymerization (CMRP) for the first time. The homopolymerization of NVCL was controlled by bis(acetylacetonato)cobalt(II) and a molecular weight as high as 46,000 g/mol could be reached with a low polydispersity. The polymerization of NVCL was also initiated from a poly(vinyl acetate)-Co(acac)2 (PVAc-Co(acac)2) macroinitiator to yield well-defined PVAc-b-PNVCL block copolymers with a low polydispersity (Mw/Mn = 1.1) up to high molecular weights (Mn = 87,000 g/mol), which constitutes a significant improvement over other techniques. The amphiphilic PVAc-b-PNVCL copolymers were hydrolyzed into unprecedented double hydrophilic poly(vinyl alcohol)-b-PNVCL (PVOH-b-PNVCL) copolymers and their temperature-dependent solution behavior was studied by turbidimetry and dynamic light scattering. Finally, the so-called cobalt-mediated radical coupling (CMRC) reaction was implemented to PVAc-b-PNVCL-Co(acac)2 precursors to yield novel PVAc-b-PNVCL-b-PVAc symmetrical triblock copolymers. [less ▲]

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See detailA convenient route for the dispersion of carbon nanotubes in polymers: Application to the preparation of electromagnetic interference (EMI) absorbers
Thomassin, Jean-Michel ULg; Vuluga, Daniela; Alexandre, Michaël ULg et al

in Polymer (2012), 53(1), 169-174

A new dispersion technique has been implemented which consists in the polymerization of a monomer in the presence of CNTs in a bad solvent of the polymer. During its formation, the polymer precipitates ... [more ▼]

A new dispersion technique has been implemented which consists in the polymerization of a monomer in the presence of CNTs in a bad solvent of the polymer. During its formation, the polymer precipitates and entraps all the CNTs. Thanks to the establishment of a suitable CNTs dispersion, this method promotes much higher electrical conductivity in the resulting nanocomposite than more conventional techniques, i.e. melt-mixing and co-precipitation. Moreover, the quantity of solvent required is much lower than in the co-precipitation method that makes this process industrially viable. One potential application of these nanocomposites has been demonstrated by the preparation of foams using the supercritical CO2 technology that present very high electromagnetic interference (EMI) absorbing properties since more than 90% of the incoming power being absorbed in the foam. [less ▲]

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See detailSynthesis of star and H-shape polymers via a combination of cobalt-mediated radical polymerization and nitrone mediated radical coupling reactions
Detrembleur, Christophe ULg; Debuigne, Antoine ULg; Altintas, Ozcan et al

in Polymer Chemistry (2012), 3(1), 135-147

Via consecutive cobalt-mediated radical polymerization (CMRP), nitrone-mediated radical coupling (NMRC) and copper catalyzed azide-alkyne cycloaddition (CuAAC), polymers with mikto-arm star and H-shape ... [more ▼]

Via consecutive cobalt-mediated radical polymerization (CMRP), nitrone-mediated radical coupling (NMRC) and copper catalyzed azide-alkyne cycloaddition (CuAAC), polymers with mikto-arm star and H-shape architecture were synthesized. Poly(vinyl acetate)40-block-poly(acrylonitrile)78-Co(acac)2 polymers were synthesized via CMRC and subsequently coupled using an alkyne functional nitrone. The coupling efficiency of the NMRC process was assessed employing N-tert-butyl a-phenyl nitrone (PBN), which is structurally very similar to the later employed coupling agent. Generally, coupling efficiencies of close to 90% or higher were observed in all cases. Since the coupling reaction yields triblock copolymers bearing an alkoxyamine functionality (and thus also an alkyne group) in the middle of the chain, well defined PEG conjugates could be obtained via CuAAC. Miktoarm star polymers of the structure (PVAc-b-PAN)2-PEG were generated as well as H-shaped material of the structure (PVAc-b-PAN)2-PEG-(PVAc-b-PAN)2 via conjugation with bifunctional PEG. In all cases, very narrow molecular weight material was obtained. Molecular weight analysis of the intermediate and the final products reveals that the hydrodynamic volume of the miktoarm star and the H-shaped materials is not substantially increased during the final conjugation reaction despite the fact that the absolute molecular weight increases by more than a factor of two in the latter case. Success of the conjugation reactions was confirmed via composition analysis via NMR. [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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See detailCobalt-mediated radical polymerization
Debuigne, Antoine ULg; Jérôme, Robert ULg; Jérôme, Christine ULg et al

in Schlüter, Dieter A.; Hawker, Craig; Sakamoto, Junji (Eds.) Synthesis of polymers: new structures and methods (2012)

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