References of "Detrembleur, Christophe"
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See detailDesign of hybrid nanovehicles for remotely triggered drug release: an overview
Liu, Ji; Detrembleur, Christophe ULg; Mornet, Stéphane et al

in Journal of Materials Chemistry B (in press)

n the past few decades, various nanovehicles have been developed as drug delivery systems, in which inorganic and organic components are integrated within a nano-object. Upon the application of remote ... [more ▼]

n the past few decades, various nanovehicles have been developed as drug delivery systems, in which inorganic and organic components are integrated within a nano-object. Upon the application of remote stimuli, e.g. alternating magnetic field, near infrared or ultrasound radiations, the release of guest molecules can be triggered in a quite controlled manner. Herein, we review different hybrid nanostructures which have already been reported for the remotely triggered release, such as those based on (1) host–guest conjugates, (2) core–corona nanoparticles, (3) polymer nanogels, (4) polymer micelles, (5) liposomes, (6) mesoporous silica particles and (7) hollow nanoparticles. Moreover, we also summarize six underlying mechanisms that govern such a kind of remotely triggered release behaviours: (1) enhanced diffusion and/or permeation, (2) thermo- or photo-labile bond cleavage, (3) fusion of phase-changed materials, (4) photo-induced isomerisation, (5) thermo-induced swelling/de-swelling of thermo-responsive polymers, and (6) destruction of the nanostructures. The ways in which different components are incorporated into an integrated hybrid nanostructure and how they contribute to the remotely triggered release behaviours are detailed. [less ▲]

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See detailOrganocatalytic synthesis of bio-based cyclic carbonates from CO2 and vegetable oils
Alves, Margot ULg; Grignard, Bruno ULg; Gennen, Sandro ULg et al

in RSC Advances (in press)

Bio-based cyclic carbonates were synthesized by coupling CO2 with epoxidized linseed oil using a catalytic platform composed of a bicomponent organocatalyst. A screening of the catalytic activity of a ... [more ▼]

Bio-based cyclic carbonates were synthesized by coupling CO2 with epoxidized linseed oil using a catalytic platform composed of a bicomponent organocatalyst. A screening of the catalytic activity of a series of organic salts and ionic liquids used in combination with (multi)phenolic or fluorinated hydrogen bond donors was realized before highlighting the synergistic effect between the organocatalyst and the most efficient cocatalysts. These kinetics studies, followed by IR spectroscopy under pressure, enabled to optimize the reaction conditions and to provide quantitative formation of the cyclocarbonated vegetable oil in short reaction time without using any organic solvent. [less ▲]

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See detailNanocomposite foams of polypropylene and carbon nanotubes: preparation, characterization, and evaluation of their performance as EMI absorbers
Tran, Minh-Phuong; Thomassin, Jean-Michel ULg; Alexandre, Michaël et al

in Macromolecular Chemistry and Physics (in press)

Highly expanded nanocomposite foams of polypropylene and carbon nanotubes (PP/CNT) are formed using supercritical carbon dioxide (scCO 2 ) technology. The foaming parameters (temperature, pressure) are ... [more ▼]

Highly expanded nanocomposite foams of polypropylene and carbon nanotubes (PP/CNT) are formed using supercritical carbon dioxide (scCO 2 ) technology. The foaming parameters (temperature, pressure) are investigated to establish their infl uence on the morphology of the resulting foams and their impact on the electrical con- ductivity. As promising electromagnetic-interference (EMI) absorbers, the EMI shielding performance of the foams is determined, and a preliminary relationship is established between foam morphology and the EMI shielding perfor- mance. The best candidates are highly expanded foams with a volume expansion of >25, containing 0.1 vol% CNTs; they are able to absorb more than 90% of the incident radiation between 25 and 40 GHz. [less ▲]

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See detailFluorinated alcohols as activators for the solvent-free chemical fixation of carbon dioxide onto epoxides
Gennen, Sandro ULg; Alves, Margot ULg; Méreau, Raphaël et al

in ChemSusChem (2015), 8(11), 1845-1849

The addition of fluorinated alcohols to onium salts provides highly efficient organocatalysts for the chemical fixation of CO2 onto epoxides under mild experimental conditions. The combination of online ... [more ▼]

The addition of fluorinated alcohols to onium salts provides highly efficient organocatalysts for the chemical fixation of CO2 onto epoxides under mild experimental conditions. The combination of online kinetic studies, NMR titrations and DFT calculations allows understanding this synergistic effect that provides an active organocatalyst for CO2/epoxides coupling. [less ▲]

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See detailA new design of organic radical batteries (ORBs): carbon nanotube buckypaper electrode functionalized by electrografting
Aqil, Abdelhafid ULg; Vlad, Alexandru; Piedboeuf, Marie-Laure ULg et al

in Chemical Communications (2015), 51(45), 9301-9304

A novel hybridmaterial displaying a fast and reversible charge storage capability is prepared by electrografting of an alkoxyamine-bearing acrylate onto a carbon nanotube buckypaper, followed by the quan ... [more ▼]

A novel hybridmaterial displaying a fast and reversible charge storage capability is prepared by electrografting of an alkoxyamine-bearing acrylate onto a carbon nanotube buckypaper, followed by the quan- titative generation of an electroactive polynitroxide. [less ▲]

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See detailNovel nanosized water soluble fluorescent micelles with embedded perylene diimide fluorophores for potential biomedical applications: Cell permeability, localization and cytotoxicity
Bryaskova, Rayna; Georgiev, Nikolai I.; Dimov, Stefan M. et al

in Materials Science & Engineering : C (2015), 51

Novel biocompatiblewater-soluble fluorescent micelleswithembedded perylene diimides (PDI) for intracellular applications have been prepared by self assembling of amphiphilic poly(vinyl alcohol)-b-poly ... [more ▼]

Novel biocompatiblewater-soluble fluorescent micelleswithembedded perylene diimides (PDI) for intracellular applications have been prepared by self assembling of amphiphilic poly(vinyl alcohol)-b-poly(acrylonitrile) (PVA-b-PAN) copolymers in the presence of synthesized fluorophores. Amphiphilic PVA-b-PAN copolymers were obtained by selective hydrolysis of well-defined poly(vinyl acetate)-b-poly(acrylonitrile) (PVAc-b-PAN) copolymer. The preparation of the novel fluorescence micelles consisting of PVA hydrophilic shell and PAN hy- drophobic core with incorporated PDI fluorophores has been confirmed by DLS and TEManalysis. The cytotoxic- ity of the water-soluble fluorophores and their internalization into living cells depending on the micellar concentration have been tested. Itwas shown that they could successfully enter in living cellswithout destroying their morphology. The results obtained indicate that the novel water-soluble fluorescent micelles with embed- ded PDI fluorophores would be suitable for potential intracellular biomedical applications. [less ▲]

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See detailGold nanorods coated with mesoporous silica shell as drug delivery system for remote near infrared light-activated release and potential phototherapy
Liu, Ji; Detrembleur, Christophe ULg; De Pauw-Gillet, Marie-Claire ULg et al

in Small (Weinheim an der Bergstrasse, Germany) (2015), 11(19), 2323-2332

In this study, we report the synthesis of a nanoscaled drug delivery system, which is composed of a gold nanorod-like core and a mesoporous silica shell (GNR@MSNP) and partially uploaded with phase ... [more ▼]

In this study, we report the synthesis of a nanoscaled drug delivery system, which is composed of a gold nanorod-like core and a mesoporous silica shell (GNR@MSNP) and partially uploaded with phase-changing molecules (1-tetradecanol, TD, Tm 39 degrees C) as gatekeepers, as well as its ability to regulate the release of doxorubicin (DOX). Indeed, a nearly zero premature release is evidenced at physiological temperature (37 degrees C), whereas the DOX release is efficiently achieved at higher temperature not only upon external heating, but also via internal heating generated by the GNR core under near infrared irradiation. When tagged with folate moieties, GNR@MSNPs target specifically to KB cells, which are known to overexpress the folate receptors. Such a precise control over drug release, combining with the photothermal effect of GNR cores, provides promising opportunity for localized synergistic photothermal ablation and chemotherapy. Moreover, the performance in killing the targeted cancer cells is more efficient compared with the single phototherapeutic modality of GNR@MSNPs. This versatile combination of local heating, phototherapeutics, chemotherapeutics and gating components opens up the possibilities for designing multifunctional drug delivery systems. [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 detailPrerparation of graphene oxide-poly(methyl methacrylate) nanocompposites by a precipitation polymerization process and their dielectric and rheological characterization
Alkarmo, Walid ULg; Thomassin, Jean-Michel ULg; Macosko, Christopher et al

Poster (2015, May 18)

The graphene sheet, a flat monolayer composed of sp2-bonded carbon atoms packed into a two-dimensional honeycomb structure, has attracted a tremendous attention due to its extraordinary electrical ... [more ▼]

The graphene sheet, a flat monolayer composed of sp2-bonded carbon atoms packed into a two-dimensional honeycomb structure, has attracted a tremendous attention due to its extraordinary electrical, thermal, and mechanical properties. Graphene nanosheets–poly(methyl methacrylate) GN/PMMA nanocomposites were prepared via a precipitation polymerization process in a water/methanol mixture and thermal or chemical reduction of graphene oxide (GO). Scanning electron and transmission electron microscopies confirmed that the precipitate consists of polymer particles (<1μm) surrounded by the GO sheets. The GO sheets acts as a surfactant and adsorbs on the interface between polymerized PMMA particles and solvent mixture. Parallel dielectric and rheological characterization demonstrated that the thermal reduction is a quite fast process without significant degradation of the polymer. In addition, the main increase in electrical conductivity occurred during the first minutes of the thermal treatment but continued for about 30 min. The absence of dramatic change in the storage modulus confirmed that the increase in conductivity was not due to alteration of the particle dispersion. The addition of GO sheets had a dramatic influence on the glass transition (Tg) temperature of PMMA with an increase of 8 °C at only 0.2 wt %. This Tg increase has been attributed to the restricted mobility of PMMA chains which have been grafted onto the graphene surfaces during the in-situ polymerization. However, at GO content higher than 0.7 wt %, the glass transition decreases. This drop may be attributed to the increase in the number of stacked graphene layers. The obtained GN/PMMA composites not only have enhanced mechanical properties but also achieved electrical conductivity higher than 10 −2 S/m at 0.4 wt % of GO. The study should open up new opportunities in the design of GN-based polymer nanocomposites. [less ▲]

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See detailNon-isocyanate polyurethane: from the monomer synthesis to foamed materials
Gennen, Sandro ULg; Alves, Margot ULg; Tassaing, Thierry et al

Poster (2015, May 18)

Polyurethane (PU) is one of the most important polymers in our everyday life with numerous applications such as thermosets, thermoplastics, elastomers, adhesives, sealants, coatings, rigid and flexible ... [more ▼]

Polyurethane (PU) is one of the most important polymers in our everyday life with numerous applications such as thermosets, thermoplastics, elastomers, adhesives, sealants, coatings, rigid and flexible foams... Classically, PUs are produced by a step-growth polymerization between diols and diisocyanates. However, isocyanates are harmful upon prolonged exposure to vapours which can lead to health issues such as asthma and skin irritation. In addition, isocyanates are produced from even more toxic and explosive phosgene. Due to these problems in combination with increasing regulatory scrutiny, there is today a need to develop isocyanate- and phosgene free- PU synthesis, also called non-isocyanate polyurethane or NIPUs. One of the most promising alternatives to the conventional synthesis of PU relies on the step-growth polymerization between bicyclic carbonate monomers and diamines, but until now, obtaining high molar mass NIPUs in a short time still remains a challenge. This study will be focused on three objectives: 1) The synthesis of CO2-sourced biscyclic carbonates by CO2/epoxide coupling using new highly efficient bicomponent organocatalysts allowing the fast conversion of epoxides into the corresponding cyclic carbonates under mild and solvent-free conditions. 2) The synthesis of high molar mass NIPUs from CO2-sourced monomers and diamines thanks to the use of efficient organocatalysts. A series of organic compounds interacting with cyclic carbonates by hydrogen bonding were first identified and their catalytic activity was highlighted by a model reaction between ethylene carbonate and a primary amine before extrapolation to NIPU synthesis. 3) The scCO2-assisted foaming of CO2-sourced NIPUs with production of potential carbon zero-emission materials with low thermal conductivity [less ▲]

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See detailNew efficient bicomponent organocatalysts for the chemical fixation of CO2 onto epoxides: a theoretical study
Alves, Margot ULg; Méreau, Raphaël; Grignard, Bruno ULg et al

Poster (2015, May 18)

Regarding the economic and environmental issues, valorising CO2 as a C1 feedstock for producing useful building blocks is seducing as it is a free and abundant waste resulting from the human activity ... [more ▼]

Regarding the economic and environmental issues, valorising CO2 as a C1 feedstock for producing useful building blocks is seducing as it is a free and abundant waste resulting from the human activity. Cyclic carbonates are useful compounds that found application as green solvents, electrolytes for lithium battery or monomers for polycarbonates or polyurethanes synthesis. These cyclocarbonates can be synthesized with a total atom economy by chemical fixation of CO2 onto epoxides using organometallic complexes or organocatalysts. To date, although this area of research has been the subject of many studies, the identification and development of (organo)catalysts highly efficient under mild experimental conditions still remains challenging. In this context, we developed a new organocatalytic platform based on the use of ammonium salts in combination with single or double hydrogen bond donor activators derived from fluorinated alcohols that showed unexpected booster effect. In this contribution, the ammonium/fluoroalcohol promoted CO2/propylene oxide coupling was investigated through detailed kinetic studies by IR spectroscopy under pressure and results were compared to the most efficient organocatalysts based on ammonium salts and (multi)phenolic derivatives that were reported in the literature. In order to finely understand the reaction mechanism, this study was completed by molecular modeling. DFT calculations showed that the addition of H-bond donors (HBD) with hexafluoroisopropanol functionalities modified the mechanism of the ammonium promoted coupling of CO2 with epoxides. HBDs dramatically decreased the epoxide ring-opening step barrier which highlights the key role of the fluorinated activators in stabilizing the intermediates and transitions states by inter- and intra-molecular hydrogen bonds. [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 detailDesign of new multifunctional nanocarriers for protein delivery
Parilti, Rahmet ULg; Jérôme, Christine ULg; Howdle, Steven M. et al

Conference (2015, May 18)

Polymeric nanoparticles have been extensively investigated for their biomedical applications especially as drug carriers. However, efficient encapsulation and delivery of therapeutic proteins in targeted ... [more ▼]

Polymeric nanoparticles have been extensively investigated for their biomedical applications especially as drug carriers. However, efficient encapsulation and delivery of therapeutic proteins in targeted manner still present challenges. This project aims to develop a novel one-pot strategy to obtain nanoparticles able to carry proteins in their core, as well as bearing targeting and/or imaging agents on their surface. In addition to this objective, polymerizations are carried out in supercritical carbon dioxide (scCO2), which confers environmentally benign features to the process. Dispersion polymerizations of hydrophilic monomer 2-hydroxyethyl methacrylate (HEMA) in are carried out in scCO2 in the presence of an initiator, cross-linker and CO2-philic photoclevable stabilizer. Upon exposure to UV light, the o-nitrobenzyl junctions present at the surface of the particles are cleaved, thus providing water dispersible hydrogels. Spherical monodisperse nanoparticles were successfully synthesized in scCO2 with two different conditions. Milder reaction conditions were achieved by using 2,2'-Azobis(4-methoxy-2,4-dimethyl valeronitrile (V70) as an initiator which opens up the platform for one-pot protein encapsulation in scCO2. [less ▲]

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See detailChitosan-coated electrospun nanofibers with antibacterial activity
Croisier, Florence ULg; Sibret, Pierre ULg; Dupont-Gillain, Christine C. et al

in Journal of Materials Chemistry B (2015), 3(17), 3508-2517

Charged nanofibers were prepared by electrospinning (ESP) poly(ε-caprolactone) with a copolymer bearing carboxylic acid functions. The presence of these functions allowed exposing some negative charges on ... [more ▼]

Charged nanofibers were prepared by electrospinning (ESP) poly(ε-caprolactone) with a copolymer bearing carboxylic acid functions. The presence of these functions allowed exposing some negative charges on the fiber surface, by dipping the fibers in a phosphate buffer. A layer of chitosan, a polycation in acidic medium, was then deposited on the nanofiber surface, thanks to electrostatic attraction. Fibers were characterized at each step of the process and the influence of the copolymer architecture on chitosan deposition was discussed. The antibacterial activity of the resulting fibers was finally assessed. [less ▲]

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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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