References of "Jérôme, Christine"
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See detailMultiple Gas-Phase Conformations of a Synthetic Linear Poly(acrylamide) Polymer Observed Using Ion Mobility-Mass Spectrometry
Haler, Jean ULg; Far, Johann ULg; Aqil, Abdelhafid ULg et al

in Journal of the American Society for Mass Spectrometry (in press)

Ion mobility-mass spectrometry (IM-MS) has emerged as a powerful separation and identification tool to characterize synthetic polymer mixtures and topologies (linear, cyclic, star-shaped ... [more ▼]

Ion mobility-mass spectrometry (IM-MS) has emerged as a powerful separation and identification tool to characterize synthetic polymer mixtures and topologies (linear, cyclic, star-shaped,...). Electrospray coupled to IM-MS already revealed the coexistence of several charge state-dependent conformations for a single charge state of biomolecules with strong intramolecular interactions, even when limited resolving power IM-MS instruments were used. For synthetic polymers, the sample's polydispersity allows the observation of several chain lengths. A unique collision cross-section (CCS) trend is usually observed when increasing the degree of polymerization (DP) at constant charge state, allowing the deciphering of different polymer topologies. In this paper, we report multiple coexisting CCS trends when increasing the DP at constant charge state for linear poly(acrylamide) PAAm in the gas phase. This is similar to observations on peptides and proteins. Biomolecules show in addition population changes when collisionally heating the ions. In the case of synthetic PAAm, fragmentation occurred before reaching the energy for conformation conversion. These observations, which were made on two different IM-MS instruments (SYNAPT G2 HDMS and high resolution multi-pass cyclic T-Wave prototype from Waters), limit the use of ion mobility for synthetic polymer topology interpretations to polymers where unique CCS values are observed for each DP at constant charge state. [less ▲]

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See detailMerging supercritical carbon dioxide and organocatalysis for the precision and green synthesis of poly(lactide)-based (co)polymers
Grignard, Bruno ULg; De Winter, Julien; Gerbaux, Pascal et al

in European Polymer Journal (in press)

Well-defined poly(lactide)-based block copolymers were synthesized by a heterogeneous solvent and metal-free green approach by using organocatalysts in supercritical carbon dioxide (scCO2). We first ... [more ▼]

Well-defined poly(lactide)-based block copolymers were synthesized by a heterogeneous solvent and metal-free green approach by using organocatalysts in supercritical carbon dioxide (scCO2). We first report on the homopolymerization of both L- and D,L- lactide by organocatalyzed Ring-Opening Polymerization (o-ROP) by using a bicomponent organocatalyst composed of a thiourea derivative and various tertiary amines as cocatalysts. Control over the molar mass and dispersity is achieved until high monomer conversion although the polylactides are insoluble in the polymerization medium. The precision synthesis of PLA-based block copolymers from various CO2-phobic hydroxyl end-capped macroinitiators such as polyethylene glycol, polycaprolactone, polybutylene succinate and polyphosphoester was then reported. Merging scCO2 with this organocatalytic system provides therefore a unique tool for the design under solvent-free conditions of poly(lactide)-based block copolymers that are insoluble in scCO2. [less ▲]

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See detailOn the phase behaviour of oxetane-CO2 and propargylic alcohols-CO2 binary mixtures by in situ infrared micro-spectrometry
Zaky, Mohamed; Boyaval, Amélie ULg; Grignard, Bruno ULg et al

in Journal of Supercritical Fluids (2017), 128

The phase behaviour of carbon dioxide/propargylic alcohols and carbon dioxide/oxetanes mixtures has been investigated using in-situ FTIR microspectrometry that allows us determining the evolution of the ... [more ▼]

The phase behaviour of carbon dioxide/propargylic alcohols and carbon dioxide/oxetanes mixtures has been investigated using in-situ FTIR microspectrometry that allows us determining the evolution of the concentration of each component in the liquid phase as a function of temperature and pressure. It was at the same time possible to look inside the cell and to visualize the expansion of the liquid phase during the increase of the pressure. The measurements were performed at three different temperatures (40, 70 and 100◦C) for pressures ranging between 0.1 and 15 MPa. Propargylic alcohol (PA), 2-methyl-3-butyn-2-ol (MBOL), 3-butyn-1-ol (BOL) and trimethylene oxide (TMO) were selected as these molecules are used in the synthesis of cyclic or polycarbonates by coupling with CO2. Thus, we determined the CO2 sorption and the concentration of the substrate in the liquid phase. Thanks to these measurements, we established the pressure-composition phase diagram for the liquid phase of these substrate/CO2 binary mixtures. [less ▲]

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See detailCO2-sourced α-alkylidene cyclic carbonates: a Step forward in the quest for functional regioregular poly(urethane)s and poly(carbonate)s
Gennen, Sandro ULg; Grignard, Bruno ULg; Tassaing, Thierry et al

in Angewandte Chemie International Edition (2017), 56(35), 1039410398

We describe a robust platform for the synthesis of a large diversity of novel functional CO2 -sourced polymers by exploiting the regio-controlled and site selective ring-opening of α- alkylidene ... [more ▼]

We describe a robust platform for the synthesis of a large diversity of novel functional CO2 -sourced polymers by exploiting the regio-controlled and site selective ring-opening of α- alkylidene carbonates by various nucleophiles. The remarkable reactivity of α-alkylidene carbonates is dictated by the exocyclic olefinic group that selectively orients the cyclic carbonate ring- opening with the formation of an enol species. The polyaddition of CO2 -sourced bis-α-alkylidene carbonates (bis-αCCs) with primary and secondary diamines provides novel regioregular functional poly(urethane)s. The reactivity of bis-αCCs is also exploited for producing new poly(β-oxo-carbonate)s by organocatalyzed polyaddition with a diol. All polyadditions were feasible under ambient conditions. This synthesis platform provides new functional variants of world-class leading polymers families (polyurethanes, polycarbonates) and valorises CO2 as a chemical feedstock. [less ▲]

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See detailMild synthesis of poly(HEMA)-networks as well-defined nanoparticles in supercritical carbon dioxide
Parilti, Rahmet ULg; Alaimo, David; Grignard, Bruno ULg et al

in Journal of Materials Chemistry B (2017), 5(29), 5806-5815

Free-radical dispersion polymerisation of 2-hydroxyethyl methacrylate was carried out in supercritical carbon dioxide (scCO2) in the presence of stabilisers based on polyethylene oxide (PEO) and poly ... [more ▼]

Free-radical dispersion polymerisation of 2-hydroxyethyl methacrylate was carried out in supercritical carbon dioxide (scCO2) in the presence of stabilisers based on polyethylene oxide (PEO) and poly(heptadecafluorodecyl acrylate) (PFDA). Different architectures of copolymers (random, palm-tree and diblock) were tested for their surface tension, cloud point and as a stabilising agent. The diblock architecture was found to be the best candidate resulting in poly(HEMA) spherical particles with a size of 316 nm. Furthermore, the effect of the CO2-phobic block (PEO) in the diblock architecture was investigated by using three different chain lengths (1000, 2000, 5000 g mol−1). By optimizing the stabiliser composition and structure, mild reaction conditions have been identified allowing us to obtain well-defined spherical cross-linked poly(HEMA) particles with a mean diameter of unprecedented low size (216 nm) at a temperature as low as 35 °C. [less ▲]

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See detailInnovative polyelectrolytes/poly(ionic liquid)s for energy and environment
Ajjan, Fátima N.; Ambrogi, Martina; Tiruye, Girum Ayalneh et al

in Polymer International (2017), 66(8), 1119-1126

This manuscript presents the work carried out within the European Project RENAISSANCE-ITN, which was dedicated to the development of innovative polyelectrolytes for energy and environmental applications ... [more ▼]

This manuscript presents the work carried out within the European Project RENAISSANCE-ITN, which was dedicated to the development of innovative polyelectrolytes for energy and environmental applications. Within the project different types of innovative polyelectrolytes were synthesized such as poly(ionic liquid)s coming from renewable or natural ions, thiazolium cations, cathechol functionalities or from a new generation of cheap deep-eutectic monomers. Further, macromolecular architectures such as new poly(ionic liquid) block copolymers and new (semi)conducting polymer/polyelectrolyte complexes were also developed. As the final goal, the application of these innovative polymers in energy and environment was investigated. Important advances in energy storage technologies included the development of new carbonaceous materials, new lignin/conducting polymer biopolymer electrodes, new iongels and single-ion conducting polymer electrolytes for supercapacitors and batteries and new poly(ionic liquid) binders for batteries. On the other hand, the use of the innovative polyelectrolytes into sustainable environmental technologies led to the development of new liquid and dry water, new materials for water cleaning technologies such as floculants, oil absorbers, new recyclable organocatalysts platform and multifunctional polymer coatings with antifouling and antimicrobial properties. All in all this article demonstrates the potential of the poly(ionic liquid)s for high-value applications in Energy & Enviromental areas. [less ▲]

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See detailBio- and CO2-sourced polyhydroxyurethanes for hydrogels coatings, foams and high performance adhesives
Gennen, Sandro ULg; Panchireddy, Satyannarayana ULg; Grignard, Bruno ULg et al

Poster (2017, June 09)

Due to concerns about global warming combined with the decrease of fossil resources, the chemical transformation of carbon dioxide (CO2) into added-value products has gained interest in both academic and ... [more ▼]

Due to concerns about global warming combined with the decrease of fossil resources, the chemical transformation of carbon dioxide (CO2) into added-value products has gained interest in both academic and industrial fields. Indeed, CO2 can be viewed as a cheap, non-toxic and renewable C1 building block precursor of sophisticated organic molecules and polymers. One representative example of CO2 transformation includes the synthesis of various (bis)cyclic carbonates via CO2/epoxide coupling.1-3 Bis-cyclic carbonates were then valorized as monomers for the synthesis of series of novel low carbon footprint poly(hydroxyurethane)s (PHUs). These polymers are now exploited to produce sustainable materials including foams for thermal insulation,4 hydrogels (for potential biomedical use)5 and high performance adhesives and glues (for metal, glass and wood). [less ▲]

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See detailPolyphosphoesters: new trends in synthesis and drug delivery applications
Jérôme, Christine ULg

Conference (2017, May 24)

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See detailMultifunctional poly(ionic liquid)s: from synthesis to applications in energy and environment
Detrembleur, Christophe ULg; Patil, Nagaraj ULg; Debuigne, Antoine ULg et al

Conference (2017, May 24)

Poly(ionic liquid)s (PILs) are a subclass of polyelectrolytes that gained an enabling role in many fields of polymer chemistry and material science. PILs combine the unique properties of ionic liquids ... [more ▼]

Poly(ionic liquid)s (PILs) are a subclass of polyelectrolytes that gained an enabling role in many fields of polymer chemistry and material science. PILs combine the unique properties of ionic liquids with the flexibility and properties of macromolecules, and provide novel attractive functions. Recently, the precision design of novel PILs by controlled/living polymerization (CLP) techniques was intensively searched for developing emerging applications. This talk will first discuss recent routes for the precision synthesis of all vinyl-imidazolium based (co)polymers in water or in organic media under non-demanding experimental conditions. We will then describe the preparation of innovative redox and surface active PILs, and show the potential of these PILs in battery applications and for multifunctional coatings. More specifically, we will show how macromolecular engineering can be exploited for designing innovative polymer cathodes for ultra-high performance Li storage with unprecedented performances (high capacities and ultra-long life-span over more than 3000 cycles at an extreme current-rate). This innovative and effective molecular design for polymer cathodes opens up new horizons in developing an economical and environmentally benign platform for large-scalable fabrication of high performance batteries. [less ▲]

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See detailDesign of polyphosphoester-based drug delivery systems by efficient thiol-ene reaction
Riva, Raphaël ULg; Vanslambrouck, Stéphanie; Ergül, Zeynep ULg et al

Poster (2017, May 23)

Thanks to their biocompatibility, biodegradability and their structure similar to natural biomacromolecules, polyphosphoesters (PPE) are appealing polymers for biomedical applications. In contrast to ... [more ▼]

Thanks to their biocompatibility, biodegradability and their structure similar to natural biomacromolecules, polyphosphoesters (PPE) are appealing polymers for biomedical applications. In contrast to polyesters, PPE properties and functionality are easily tuned via the chemical nature of the lateral chains. To enhance the drug loading capacity of PPE-based micelles used as carriers for the delivery of poorly soluble drugs, an efficient strategy to increase the lipophilicity of the PPE block of polyethylene oxide (PEO)-b-PPE amphiphilic copolymers has been investigated. A PEO-b-PPE copolymer bearing pendant vinyl groups along the PPE block was synthesized and then modified by thiol-ene click reaction with thiols bearing either a long linear alkyl chain (dodecyl) or a tocopherol moiety. Ketoconazole was used as model for hydrophobic drugs. Comparison of the loading contents and release profiles with PEO-b-PPE bearing shorter pendant groups is presented evidencing the key role of the structure of the pendant group on the PPE backbone. Finally, the low cytotoxicity of these novel PEO-b-PPE copolymers was also demonstrated. The tocopherol derivative was evidenced as particularly promising for drug delivery systems. [less ▲]

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See detailFunctional emulsion-templated porous polymers by macromolecular surfactant anchoring strategies
Mathieu, Kevin ULg; Jérôme, Christine ULg; Debuigne, Antoine ULg

Poster (2017, May 22)

Macroporous polymer monoliths with interconnected structures have attracted considerable interest in the fields of supported catalysis, chromatography, water purification, etc. A popular and ... [more ▼]

Macroporous polymer monoliths with interconnected structures have attracted considerable interest in the fields of supported catalysis, chromatography, water purification, etc. A popular and straightforward synthesis approach for such open-cell polymers is based on the polymerization of high internal phase emulsion (HIPE). Advanced functional polyHIPEs were also produced via different post-modification strategies but the latter often consists in tedious multi-step processes. This communication aims at reporting an efficient one-pot macromolecular surfactant-assisted method for the simultaneous synthesis and chemical functionalization of macroporous polyHIPEs. Briefly, amphiphilic block copolymers prepared by nitroxide-mediated radical polymerization (NMP) or reversible addition-fragmentation chain transfer (RAFT) were used as HIPE stabilizers and grafted at the surface of the walls of polyHIPE during the polymerization process. The impact of the controlled radical polymerization mechanism on the porous structure, openness and functionalization of the monoliths will be discussed. This strategy was also implemented with alkyne-terminated copolymers in order to decorate the surface of the polyHIPE’s cavities with “clickable” moieties which broadens the scope of functional macroporous polymers. [less ▲]

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See detailMerging CO2 transformation and utilization with renewable bio-resources: a step forward to a double vision of sustainable chemistry
Grignard, Bruno ULg; Poussard, Loïc; Raquez, Jean-Marie et al

Conference (2017, May 22)

Valorizing waste CO2 as a cheap, inexhaustible and renewable C1 feedstock is an early stage technology with strong innovation potential that imposes itself as a strategic driver for developing future low ... [more ▼]

Valorizing waste CO2 as a cheap, inexhaustible and renewable C1 feedstock is an early stage technology with strong innovation potential that imposes itself as a strategic driver for developing future low carbon footprints materials. Beside its use as raw chemical, the “physical” valorization of CO2 in a series of industrial cost-efficient processes will also accelerate the development of a low carbon economy and support the elaboration of a global low carbon vision scheme. The synergistic and paradigm-transforming holistic project we propose perfectly illustrates these concepts by encompassing a “cradle” to “grave” vision, i.e. from the products conception from CO2 and bio-resources to their production and processing through sustainable processes compatible with existing industrial relevant infrastructures. It focuses on the elaboration of sustainable isocyanate-free polyurethane foams with promising thermal insulation properties. By its objectives, this study also proposes an ideal alternative to the conventional synthesis of PUs and a practical answer to the challenge the PU sector is facing due to changes in the REACH regulations limiting the use of isocyanates. The success of the project relies on 3 key steps involving: i) The synthesis of bio- and CO2-sourced cyclic carbonates monomers: Due to the low reactivity of CO2 versus epoxides, addition of catalysts is necessary. To overcome this limitation, we developed a new highly-efficient bicomponent homogeneous organocatalyst that showed unexpected activity for the fast (within a few minutes) and selective addition of CO2 onto model epoxides and epoxidized vegetable oil under solvent-free and mild experimental conditions at the multiKg scale. The use of this powerful dual organocatalyst was further extended to the first organocatalytic coupling of CO2 with less reactive oxetanes to produce hydroxyl telechelic oligocarbonate entering the synthesis of CO2-sourced conventional PUs. - The synthesis of sustainable bio- and CO2- sourced isocyanates-free polyurethanes (NIPU): Sustainable NIPUs were produced by step-growth polymerization between the so-produced bio- and CO2-sourced cyclic carbonates and biosourced amino-telechelic comonomers derived from linseed fatty acids according to a process compatible with existing industrial infrastructures (extrusion). - The foaming of NIPUs: Sustainable foams with thermal insulation were produced by the supercritical CO2 assisted foaming technology. Due to its solubility in polymers, CO2 can replace conventional flammable VOCs and ozone depletion physical blowing agents as hydro- or fluorocarbons exhibiting long atmospheric life-time and/or mean global warming potential 2800 higher than CO2. By finely choosing the CO2 impregnation and the foaming conditions, low density microcellular NIPU foams with a thermal conductivity as low as 0.050 Wm-1K-1 were produced. Our study shows that CO2 is not only sequestered in the material for long-term application, but is also valorized as a blowing agent in the production of sustainable thermally insulating NIPU foams. Such low carbon footprints materials will contribute to energy conservation and savings by reducing CO2 emissions. [less ▲]

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See detailSynthesis of cross-linked P(HEMA) particles in supercritical carbon dioxide for protein delivery
Parilti, Rahmet ULg; Howdle, Steven M.; Jérôme, Christine ULg

Poster (2017, May 22)

This project aims to develop a novel one-pot strategy to obtain well-defined cross-linked particles able to carry peptides/proteins in their core, as along with targeting and/or imaging agents on their ... [more ▼]

This project aims to develop a novel one-pot strategy to obtain well-defined cross-linked particles able to carry peptides/proteins in their core, as along with targeting and/or imaging agents on their surface. In addition to this objective, polymerisations will be carried out in supercritical carbon dioxide (scCO2), which confers environmentally benign features to the process. Here, we investigate the feasibility of free radical dispersion polymerizations of 2-hydroxyethyl methacrylate (HEMA) in scCO2. In order to ensure the successful dispersion in scCO2 novel diblock CO2-philic surfactants are employed. These diblock surfactants are formed from two different segments, a CO2-phobic block which has an affinity to the growing particles and a second CO2-philic block that ensures surfactant solubility. [less ▲]

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See detailProtein encapsulation into nanostructured CaCO3 microparticles templated by PEO-b-polyphosphoester using a supercritical CO2 process
Ergül, Zeynep ULg; Debuigne, Antoine ULg; Calvignac, Brice et al

Poster (2017, May 22)

The use of calcium carbonate microparticles is becoming more and more attractive in biomedical applications as proteins carriers for their controlled delivery in the body. We investigate the protein ... [more ▼]

The use of calcium carbonate microparticles is becoming more and more attractive in biomedical applications as proteins carriers for their controlled delivery in the body. We investigate the protein encapsulation by in situ precipitation of CaCO3 particles prepared by a process based on supercritical CO2 and using a new type of degradable well-defined double hydrophilic block copolymer composed of poly(ethylene oxide) and polyphosphoester block with an affinity for calcium like poly(phosphotriester)s bearing pendent carboxylic acids on each repeating monomer unit which evidenced an efficient structure for templating the formation of CaCO3 leading to unprecedented small-sized particles. Lysozyme was chosen as a model for therapeutic protein for its availability and ease of detection. It was found that by this green process, loading into the CaCO3 microparticles with a diameter about 2 μm can be obtained as determined by scanning electron microscopy. A protein loading up to 6.5% active lysozyme was measured by a specific bioassay (Micrococcus lysodeikticus). By encapsulating fluorescent-labelled lysozyme (lysozyme-FITC), the confocal microscopy images confirmed its encapsulation and suggested a core–shell distribution of lysozyme into CaCO3. [less ▲]

Detailed reference viewed: 31 (1 ULg)
See detailFunctional emulsion-templated macroporous polymers via controlled radical polymerization
Mathieu, Kevin ULg; Jérôme, Christine ULg; Debuigne, Antoine ULg

Conference (2017, May 05)

Macroporous polymer monoliths with interconnected structures have attracted considerable interest in the fields of supported catalysis, chromatography, water purification, etc. A popular and ... [more ▼]

Macroporous polymer monoliths with interconnected structures have attracted considerable interest in the fields of supported catalysis, chromatography, water purification, etc. A popular and straightforward synthesis approach for such open-cell polymers is based on the emulsion-templated polymerization. In this strategy, a major phase is dispersed in a minor continuous phase containing monomers, cross-linker, initiator and surfactant. The curing of the continuous phase followed by the removal of the dispersed phase leads to a monolith with voids interconnected by pores. Size and number of the latters are influenced by several parameters and especially by the nature of the surfactant. Consequently, we prepared by controlled radical polymerization a series of well-defined amphiphilic copolymers having different hydrophilic-lipophilic balance (HLB) and chain-ends, used it as stabilizers for the emulsion-templated polymerizations and demonstrated the crucial effect of the macromolecular features as well as the concentration on the foam morphology. Secondly, the physical and the chemical anchoring of the macromolecular surfactants at the surface of the pores were also considered for tuning the surface properties of the porous monoliths in one step. This strategy was also implemented with alkyne-terminated copolymers in order to decorate the surface of the cavities with “clickable” moieties which broadens the scope of functional macroporous polymers. [less ▲]

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See detailSynthesis of hierarchical N-doped porous carbon structure/nanospheres Fe2O3 composites and its application in lithium-ion battery as lithium-ion anodes
Alkarmo, Walid ULg; Ouhib, Farid ULg; Aqil, Abdelhafid ULg et al

Poster (2017, May 04)

Nitrogen-doped porous carbons are of special interest, because their unique physical properties such as high surface area, multidimensional electron transport pathways and good mechanical strength, and ... [more ▼]

Nitrogen-doped porous carbons are of special interest, because their unique physical properties such as high surface area, multidimensional electron transport pathways and good mechanical strength, and are thus very important for applications in the fields of catalysis, environment techniques and energy generation and storage. Moreover, nitrogen-doping can be further amplified in a porous structure that bears a high surface area to increases their materials performance in electrochemical devices, such as double layer capacitors and lithium-ion batteries. In addition, nitrogen-doping can enhance the lithium insertion, between the nitrogen-doped carbon material and lithium. And it can create a large number of defects in the porous configuration and offer more active sites for lithium insertion. Toward this goal, a hierarchically structured macro- and mesoporous N-doped carbon with dispersed Fe2O3 nanoparticles (NDC@Fe2O3) is prepared by thermal treatment of a novel composite composed by PMMA particles decorated by graphene oxide (GO), PPy and iron salts. The NDC@Fe2O3 composite exhibited high surface area with a hierarchical pores structure. Integrated as a lithium ion battery anode, NDC@Fe2O3 exhibited high reversible capacity of 930 mA h/g over 200 cycles. The combination of Fe2O3 nanoparticles with nitrogen-doped porous carbons to form hybrid anode has been an efficient way to maintain the electronic integrity of the whole electrode since the carbon acts as a buffer layer to accommodate the volume variation and to provide multidimensional electron transport pathways during the charge/discharge process. [less ▲]

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See detailDesign of polyphosphoester coplymers as scaffolds for tissue engineering applications
Shah, Urmil ULg; Ergül, Zeynep ULg; Jérôme, Christine ULg

Poster (2017, May 04)

Polymers with repeating phosphoester linkages in the backbone are biodegradable and emerged as a promising class of novel biomaterials. In contrast to polyesters, the pentavalency of the phosphorus atom ... [more ▼]

Polymers with repeating phosphoester linkages in the backbone are biodegradable and emerged as a promising class of novel biomaterials. In contrast to polyesters, the pentavalency of the phosphorus atom offers a large diversity of structures and as a consequence a wide range of properties for these materials. This study aims at taking profit of this easy functionalization to synthesize a series of degradable polymers of precisely tailored properties especially elasticity, hydrophilicity and functionality. We aim at developing a set of degradable materials in which only elasticity is varied keeping unchanged other parameters such as hydrophilicity, which remains quite a challenge. For that purpose, we have synthesized by organocatalyzed ring-opening polymerization,random di- and terpolymers between various cyclic phosphoesters bearing a short side-chain (hydrophilic), a longer side-chain (hydrophobic) and an unsaturated side-chain (butenyl)able to cross-link under UV irradiation. Playing on the composition of these copolymers, the cross-linking density and the hydrophilicity can be tuned quite independently. In the future, these materials will be used as model scaffolds to study the growth and differentiation of stem cells. [less ▲]

Detailed reference viewed: 46 (5 ULg)
See detailThiol-ene reaction: an efficient tool to design polyphosphoester-based drug delivery systems
Riva, Raphaël ULg; Vanslambrouck, Stéphanie; Ergül, Zeynep ULg et al

Poster (2017, May 04)

Thanks to their biocompatibility, biodegradability and their structure similar to natural biomacromolecules, polyphosphoesters (PPE) are appealing polymers for biomedical applications. In contrast to ... [more ▼]

Thanks to their biocompatibility, biodegradability and their structure similar to natural biomacromolecules, polyphosphoesters (PPE) are appealing polymers for biomedical applications. In contrast to polyesters, PPE properties and functionality are easily tuned via the chemical nature of the lateral chains. To enhance the drug loading capacity of PPE-based micelles used as carriers for the delivery of poorly soluble drugs, an efficient strategy to increase the lipophilicity of the PPE block of polyethylene oxide (PEO)-b-PPE amphiphilic copolymers has been investigated. A PEO-b-PPE copolymer bearing pendant vinyl groups along the PPE block was synthesized and then modified by thiol-ene click reaction with thiols bearing either a long linear alkyl chain (dodecyl) or a tocopherol moiety. Ketoconazole was used as model for hydrophobic drugs. Comparison of the loading contents and release profiles with PEO-b-PPE bearing shorter pendant groups is presented evidencing the key role of the structure of the pendant group on the PPE backbone. Finally, the low cytotoxicity of these novel PEO-b-PPE copolymers was also demonstrated. The tocopherol derivative was evidenced as particularly promising for drug delivery systems. [less ▲]

Detailed reference viewed: 35 (2 ULg)
See detailSynthesis of cross-linked poly(HEMA) microparticles in supercritical carbon dioxide for sustained delivery
Caprasse, Jérémie ULg; Parilti, Rahmet ULg; Riva, Raphaël ULg et al

Poster (2017, May 04)

Microgels are micro-sized polymer networks able to swell or shrink depending on the environment. They find applications in many fields such as for environmental purpose or especially in the biomedical ... [more ▼]

Microgels are micro-sized polymer networks able to swell or shrink depending on the environment. They find applications in many fields such as for environmental purpose or especially in the biomedical field for tissue engineering or controlled drug-delivery applications. Indeed, the use of microgels allows a controlled and sustained release of an encapsulated active ingredient (AI), avoiding Burst release. This work aims at reporting on the solvent-free synthesis of well-defined hydrogel microparticles according to a free radical dispersion polymerization of hydroxyethyl methacrylate (HEMA) in supercritical carbon dioxide (scCO2) which confers environmentally benign features to the process2. For that purpose, a dedicated polymer surfactant has been designed by RAFT polymerization, i.e. poly(ethylene oxide-b-heptadecafluorodecyl acrylate) diblock copolymer with a photocleavable group at the junction of both blocks and used as stabilizer for the HEMA dispersion polymerization in scCO2. The synthesis conditions (stabilizer concentration, temperature and CO2 pressure,…) adapted for the in situ encapsulation of an active ingredient have been studied. Then, the photocleavage of the fluorinated block of the polymer stabilizer allows the further swelling of the polyHEMA particles in water and the sustained release of the encapsulated active ingredient through the microgels. This eco-friendly process allowing the formation of well-defined hydrogel particles, showing a sustain release of their content is quite promising for a high scale microparticles production. Microgels are micro-sized polymer networks able to swell or shrink depending on the environment. They find applications in many fields such as for environmental purpose or especially in the biomedical field for tissue engineering or controlled drug-delivery applications. Indeed, the use of microgels allows a controlled and sustained release of an encapsulated active ingredient (AI), avoiding Burst release. [less ▲]

Detailed reference viewed: 45 (2 ULg)