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See detailEthylene/vinyl acetate-based macrocycles via organometallic-mediated radical polymerization and CuAAC ‘click’ reaction
Demarteau, Jérémy ULiege; De Winter, Julien; Detrembleur, Christophe ULiege et al

in Polymer Chemistry (in press)

Recent advances in organometallic-mediated radical polymerization led to unique α,ω-difunctional poly(vinyl acetate) (PVAc) and ethylene/vinyl acetate copolymers (EVA). A copper- catalyzed Huisgen dipolar ... [more ▼]

Recent advances in organometallic-mediated radical polymerization led to unique α,ω-difunctional poly(vinyl acetate) (PVAc) and ethylene/vinyl acetate copolymers (EVA). A copper- catalyzed Huisgen dipolar cycloaddition ring-closure reaction was applied to these difunctional precursors paving the way to unprecedented PVAc and/or EVA macrocycles, and to their PVOH- and EVOH-counterparts after hydrolysis. [less ▲]

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See detailReinforced poly(hydroxyurethane) thermosets as high performance adhesives for aluminum substrates
Panchireddy, Satyannarayana ULiege; Thomassin, Jean-Michel ULiege; Grignard, Bruno ULiege et al

in Polymer Chemistry (2017), 8(38), 5897-5909

Poly(hydroxyurethane) (PHU) thermosets reinforced with (functional) nanofillers were developed to design high performance adhesives for bare aluminum. Solvent-free cyclic carbonate/amine/PDMS formulations ... [more ▼]

Poly(hydroxyurethane) (PHU) thermosets reinforced with (functional) nanofillers were developed to design high performance adhesives for bare aluminum. Solvent-free cyclic carbonate/amine/PDMS formulations loaded with native, epoxy- or cyclic carbonate-functionalized ZnO nanofillers were premixed before deposition and thermal curing onto Al. The results highlight that the addition of PDMS prevents PHUs from delamination of the Al surface by increasing the adhesive hydrophobicity and thus limiting the water uptake. The dispersion of functional fillers within PHUs improves their thermal and mechanical properties. Benchmarking of the adhesive performances of the reinforced PHU glues with existing PHU formulations attests for the benefits of dispersing functional fillers and PDMS within the resin and evidences a 270% increase of the shear strength of reinforced PHUs adhesives compared to formulations reported in the literature. [less ▲]

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See detailPhotosensitive polydimethylsiloxane networks for adjustable-patterned films
Jellali, Rachid; Alexandre, Michaël; Jérôme, Christine ULiege

in Polymer Chemistry (2017), 8(16), 2499-2508

Polydimethylsiloxanes (PDMSs) bearing photoreactive coumarin groups have been synthesized by amida- tion of a coumarin acid chloride derivative with various amine-functionalized PDMSs. Upon exposure to UV ... [more ▼]

Polydimethylsiloxanes (PDMSs) bearing photoreactive coumarin groups have been synthesized by amida- tion of a coumarin acid chloride derivative with various amine-functionalized PDMSs. Upon exposure to UV light having a wavelength of above 300 nm, multifunctional coumarin-PDMSs are transformed into covalent networks via [2 + 2] photocycloaddition of two coumarin moieties forming a cyclobutane ring. Taking advantage of the possible localized irradiation through a photomask, a novel concept to generate patterned PDMS films with various surface topologies was demonstrated. This concept is based on the combination of a low molar mass difunctional PDMS with a multifunctional PDMS of a high molar mass forming a photoreversible network allowing osmotic diffusion of a linear PDMS-coumarin of low mole- cular weight in a loosely crosslinked network. Advantageously, illumination by a light source at 254 nm induces the photocleavage of the cyclobutane cross-links offering some photo-induced reversibility to the PDMS network. These novel photo-responsive networks are interesting for several applications, in photo-adaptable biomedical implants (particularly photo-adjustable intra-ocular lenses), photo-tuneable patterned microsystems (e.g. for microfluidics) and photo-switchable controlled release systems. [less ▲]

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See detailSimultaneous synthesis and chemical functionalization of emulsion-templated porous polymers using nitroxide-terminated macromolecular surfactants
Mathieu, Kevin ULiege; De Winter, Julien; Jérôme, Christine ULiege et al

in Polymer Chemistry (2017), 8(11), 1850-1861

The design of functional 3D macroporous monoliths has become a necessity for a wide range of applications. Traditional post-modification strategies of porous materials are efficient but often consist in ... [more ▼]

The design of functional 3D macroporous monoliths has become a necessity for a wide range of applications. Traditional post-modification strategies of porous materials are efficient but often consist in tedious multi-steps processes. This work describes a straightforward macromolecular surfactant-assisted method for producing chemically functionalized macroporous polyHIPEs with interconnected structures. Accordingly, high internal phase emulsion-templated polymerizations were implemented in the presence of SG1-terminated amphiphilic copolymers prepared by nitroxide- mediated radical polymerization (NMP). The latter served as both stabilizers and functionalizing agents upon thermal activation of its terminal alkoxyamine and covalent anchoring of the released radical copolymer onto the walls of the scaffold. The effect of the polymerization temperature on the functionalization and openness of the final porous materials was explored. As a result, a range of open-cell styrene and acrylate-based polyHIPEs chemically grafted with PEO were obtained. Moreover, polyHIPEs were also decorated with alkyne-bearing PEO and subsequently modified via CuAAc click chemistry in order to demonstrate the potential of this macromolecular surfactants-assisted functionalization method. [less ▲]

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See detailPhotocleavable stabilizer for the preparation of PHEMA nanogels by dispersion polymerization in supercritical carbon dioxide
Alaimo, David; Grignard, Bruno ULiege; Kuppan, Chandrasekar et al

in Polymer Chemistry (2017), 8(3), 581-591

A new photo-sensitive diblock copolymer composed of a hydrophilic sequence of poly(ethylene oxide) (PEO) linked to a CO2-philic sequence of poly(1H,1H,2H,2H-heptadecafluorodecyl acrylate) (PFDA) by a ... [more ▼]

A new photo-sensitive diblock copolymer composed of a hydrophilic sequence of poly(ethylene oxide) (PEO) linked to a CO2-philic sequence of poly(1H,1H,2H,2H-heptadecafluorodecyl acrylate) (PFDA) by a light sensitive o- nitrobenzyl group was successfully synthesized by RAFT polymerization and used as stabilizer for the free radical polymerization of 2-hydroxyethyl methacrylate (HEMA) in dispersion in ?,?,?-trifluorotoluene and supercritical carbon dioxide (scCO2). Thanks to this fluorinated stabilizer, well-defined particles of PHEMA down to 350 nm of diameter were produced in scCO2. Advantageously, the photocleavable group at the block junction of the stabilizer could be cleaved by exposing the particles to UV light so that the fluorinated block could be extracted in TFT or scCO2. As supported by X-ray photoelectron spectroscopy (XPS) analysis, up to 80 % of the fluorinated block of the stabilizer can be removed, leading to efficient swelling and dispersion of the resulting PHEMA nanogels in water. [less ▲]

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See detailTransparent superhydrophobic coatings from amphiphilic-fluorinated block copolymers synthesized by aqueous polymerization-induced self-assembly
Ouhib, Farid ULiege; Dirani, Ali; Aqil, Abdelhafid ULiege et al

in Polymer Chemistry (2016), 7(24), 3998-4003

Preparation of transparent and superhydrophobic coatings by co-deposition of an aqueous solution of an amphiphilic fluorinated block copolymer (FBC) with silica particles was developped. Spin- coating of ... [more ▼]

Preparation of transparent and superhydrophobic coatings by co-deposition of an aqueous solution of an amphiphilic fluorinated block copolymer (FBC) with silica particles was developped. Spin- coating of this aqueous solution onto glass followed by an appropriate thermal treatment promotes the self-assembly of the hybrid material with the formation of superhydrophobic, robust and transparent coatings. [less ▲]

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See detailDirect one-pot synthesis of poly(ionic liquid) nanogels by cobalt-mediated radical cross-linking copolymerization in organic or aqueous media
Weiss-Maurin, Mathilde ULiege; Cordella, Daniela ULiege; Jérôme, Christine ULiege et al

in Polymer Chemistry (2016), 7(14), 2521-2530

Nanogels of controlled kinetic chain length were synthesized by cobalt-mediated radical cross-linking copolymerization (CMRccP) involving a vinyl monomer and a divinyl cross-linker. This strategy was ... [more ▼]

Nanogels of controlled kinetic chain length were synthesized by cobalt-mediated radical cross-linking copolymerization (CMRccP) involving a vinyl monomer and a divinyl cross-linker. This strategy was first validated to achieve neutral poly(vinyl acetate) nanogels by CMRccP of vinyl acetate and divinyl adipate as cross-linker, at 40 °C, in presence of an alkyl- cobalt(III) serving both as initiator and controlling agent, using ethyl acetate as solvent. Poly(ionic liquid) nanogels were then directly obtained by CMRccP of N-vinyl-3-ethyl imidazolium bromide, in presence of 1,13-divinyl-3-decyl diimidazolium bromide as cross-linker. CMRccP experiments could be conducted either in organic solvent using dimethyl formamide or, more interestingly, in aqueous solution, demonstrating the robustness and the versatility of this one-step process. Chain extensions of PILs nanogels were also carried out in water, forming core-shell structures, thus opening new avenues in the design of functional nanogels. [less ▲]

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See detailFar beyond primary poly(vinylamine)s through free radical copolymerization and amide hydrolysis
Dréan, Mathilde ULiege; Guégan, Philippe; Jérôme, Christine ULiege et al

in Polymer Chemistry (2016), 7(1), 69-78

Due to their affinity for many supports, their pH responsiveness, metal binding capacity and polyelectro- lyte complexation, poly(vinylamine) derivatives have attracted attention for many applications ... [more ▼]

Due to their affinity for many supports, their pH responsiveness, metal binding capacity and polyelectro- lyte complexation, poly(vinylamine) derivatives have attracted attention for many applications including coatings, water purification, or gas membrane separation. Nevertheless, most of them possess only pendant primary amines despite the possible benefits of incorporating different amino groups along the chain. In this work, a straightforward and scalable synthesis route towards polymers bearing primary and secondary amines, as well as imidazole groups, is reported. The general strategy relies on the radical copolymerization of different vinylamides and vinyl imidazoles followed by the hydrolysis of the resulting poly(vinylamide) derivatives. Binary and ternary free radical copolymerizations of N-vinylacetamide (NVA), N-methyl vinylacetamide (NMVA) and 1-vinylimidazole (VIm) were investigated and the reactivity ratios for each copolymerization system were determined. Thanks to these values a series of statistical copolymers with predictable composition and low deviation over the chain distribution could then be synthesized. Finally, the acidic hydrolysis of the acetamide functions towards the corresponding amine was performed and optimized. Copolymers containing various pendant amino groups and with low dispersity in the chain composition could be obtained, which opens new perspectives for the above mentioned applications. [less ▲]

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See detailLow bandgap copolymers based on monofluorinated isoindigo towards efficient polymer solar cells
Tomassetti, Mirco ULiege; Ouhib, Farid ULiege; Wislez, Arnaud ULiege et al

in Polymer Chemistry (2015), 6(33), 6040-6049

To explore the effectiveness of monofluorinated isoindigo as an electron-deficient building block in push–pull conjugated polymers for organic solar cell applications, four low bandgap copolymers are ... [more ▼]

To explore the effectiveness of monofluorinated isoindigo as an electron-deficient building block in push–pull conjugated polymers for organic solar cell applications, four low bandgap copolymers are effectively synthesized and characterized. The effects of fluorine introduction, thiophene spacer length and polymer molar mass on the general electro-optical polymer characteristics, thin film blend micro- structure and electronic performance are investigated. Isoindigo monofluorination effectively improves the power conversion efficiency from 2.8 up to 5.0% upon molar mass optimization, without using any processing additives or post-treatments. [less ▲]

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See detailMussel-inspired protein-repelling ambivalent block copolymers: controlled synthesis and characterization
Patil, Nagaraj ULiege; Falentin-Daudré, Céline; Jérôme, Christine ULiege et al

in Polymer Chemistry (2015), 6(15), 2919-2933

This paper describes the reversible addition–fragmentation chain transfer (RAFT) polymerization of mussel-inspired acetonide-protected dopamine (meth)acrylamide monomers (ADA and ADMA) and its ... [more ▼]

This paper describes the reversible addition–fragmentation chain transfer (RAFT) polymerization of mussel-inspired acetonide-protected dopamine (meth)acrylamide monomers (ADA and ADMA) and its implementation to the synthesis of innovative ambivalent block copolymers. They consist of a hydro- phobic poly((meth)acrylamide) block functionalized by catechols and a hydrophilic segment of a poly- ((meth)acrylate) bearing pendent PEG chains. For the first time, a series of well-defined P(PEGAm-b-ADAn) and P(ADMAn-b-PEGMAm) diblock copolymers across a range of molar masses (13–42 kg mol−1) with low molar mass dispersities (Đ = 1.12 − 1.25) were reported. Post polymerization, trifluoroacetic acid (TFA) treatment yields block copolymers bearing free-catechol units in quantitative yields (>95%) with a slight noticeable hydrolysis of pendent-PEG units (2%–4%). The self-assembly of the amphiphilic block copoly- mers into spherical micelles was demonstrated by 1H NMR, DLS and TEM imaging techniques. Real-time quartz crystal microbalance with dissipation monitoring (QCM-D) studies revealed that free-catechol groups were necessary for a strong anchoring onto gold and stainless steel surfaces because acetonide- protected and catechol-oxidized block copolymers completely desorbed from the surface in the rinsing step. The ambivalent nature of catechol functionalized block copolymers was studied by bovine serum albumin (BSA) adsorption on polymer modified surfaces, which displayed improved resistance against BSA adsorption, when compared to an unmodified surface. [less ▲]

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See detailDouble thermo-responsive hydrogels from poly(vinylcaprolactam) containing diblock and triblock copolymers
Thomassin, Jean-Michel ULiege; Mathieu, Kevin ULiege; Kermagoret, Anthony ULiege et al

in Polymer Chemistry (2015), 6(10), 1856-1864

The thermally-induced gelation and gel properties of concentrated aqueous solutions of double thermoresponsive poly(N-vinylamide)-based di- and triblock copolymers are studied by rheology. The copolymers ... [more ▼]

The thermally-induced gelation and gel properties of concentrated aqueous solutions of double thermoresponsive poly(N-vinylamide)-based di- and triblock copolymers are studied by rheology. The copolymers under investigation, prepared by cobalt-mediated radical polymerization and coupling reactions, are composed of poly(vinylcaprolactam) (PNVCL) blocks and of a statistical poly(vinylcaprolactam-stat-vinylpyrrolidone) segment with a cloud point temperature (TCP) higher than that of PNVCL. Heating the di- and triblock solutions beyond the first phase transition temperature favors gel formation while heating above the second TCP leads to opaque gels without macroscopic demixing. Moduli of the triblock hydrogels are systematically higher than those of the corresponding diblocks, even above the second transition. Rheological data suggest distinct micellar structures for each copolymer architecture: densely packed micelles of diblocks and 3-D networks of bridged micelles for triblocks. Strain sweep experiments also emphasize the positive effect of the micelle bridging on the elasticity and stability of the hydrogels. The formation and properties of the obtained gels are also shown to depend on the copolymer concentration, block length, and composition. Addition of salt also allows us to tune the phase transition temperatures of these double thermoresponsive hydrogels. [less ▲]

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See detailImproved photo-induced cobalt-mediated radical polymerization in continuous flow photoreactors
Kermagoret, Anthony; Wenn, Benjamin; Debuigne, Antoine ULiege et al

in Polymer Chemistry (2015), 6

The implementation of cobalt-mediated radical polymerization (CMRP) for continuous microreactor synthesis is described. We demonstrate how the utilization of flow photoreactors allows the speed up of the ... [more ▼]

The implementation of cobalt-mediated radical polymerization (CMRP) for continuous microreactor synthesis is described. We demonstrate how the utilization of flow photoreactors allows the speed up of the polymerization of vinyl acetate (VAc) under UV irradiation without loss of polymerization control. Microfluidics under UV irradiation has also been successfully implemented for the copolymerization of VAc with a less reactive olefin 1-octene (1-Oct). Reactivity ratios were deduced for this copolymerization system, and poly(VAc-co-1-Oct) copolymers containing up to 50 mol% of 1-Oct were synthesized. To the best of our knowledge, this is the first report on a photopolymerization where continuous flow techniques not only led to an improvement of reaction rates and dispersity, but also led to the avoidance of significant side-products that were observed in batch processing [less ▲]

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See detailDouble thermoresponsive di- and triblock copolymers based on N-vinylcaprolactam and N-vinylpyrrolidone: synthesis and comparative study of solution behaviour
Kermagoret, Anthony ULiege; Mathieu, Kevin ULiege; Thomassin, Jean-Michel ULiege et al

in Polymer Chemistry (2014), 5(22), 6534-6544

Poly(N-vinylcaprolactam) (PNVCL) and poly(N-vinylpyrrolidone) (PNVP) are water soluble polymers of interest especially in the biomedical field. Moreover, PNVCL is characterized by a lower critical ... [more ▼]

Poly(N-vinylcaprolactam) (PNVCL) and poly(N-vinylpyrrolidone) (PNVP) are water soluble polymers of interest especially in the biomedical field. Moreover, PNVCL is characterized by a lower critical solution temperature close to 36 °C in water, which makes it useful for the design of thermoresponsive systems. In this context, we used the cobalt-mediated radical polymerization (CMRP) and reaction coupling (CMRC) for synthesizing a series of well-defined NVCL and NVP-based copolymers, including statistical copolymers as well as double thermoresponsive diblocks and triblocks. Dynamic light scattering and turbidimetry analyses highlighted the crucial impact of the copolymer composition and architecture on the cloud point temperature (TCP) of each segment and also their influence on the multistep assembly behaviour of block copolymers. Addition of NaCl enabled us to adjust the inter-TCP range of the di- and triblock in which selective precipitation of one block and self-assembly of the copolymer were favoured. Overall, data presented here provide a basis for the synthesis of a broad range of NVCL/NVP based copolymer architectures with a tunable thermal response in water. [less ▲]

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See detailBlock, random and palm-tree amphiphilic fluorinated copolymers: controlled synthesis, surface activity and use as dispersion polymerization stabilizers
Alaimo, David ULiege; Beigbeder, Alexandre; Dubois, Philippe et al

in Polymer Chemistry (2014), 5(18), 5273-5282

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See detailThermo-responsive gold/poly(vinyl alcohol)-b-poly(N-vinylcaprolactam) core–corona nanoparticles as a drug delivery system
Liu, Ji ULiege; Detrembleur, Christophe ULiege; Hurtgen, Marie et al

in Polymer Chemistry (2014), 5(18), 5289-5299

Core–corona gold/poly(vinyl alcohol)-b-poly(N-vinylcaprolactam) nanoparticles (gold@PVOH-b-PNVCL NPs) were fabricated via an in situ method, where a gold salt was reduced within the macromolecular aqueous ... [more ▼]

Core–corona gold/poly(vinyl alcohol)-b-poly(N-vinylcaprolactam) nanoparticles (gold@PVOH-b-PNVCL NPs) were fabricated via an in situ method, where a gold salt was reduced within the macromolecular aqueous solution. Arrangement of macromolecular chains on the surface of gold cores was studied by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy and infrared spectroscopy. The responsiveness to temperature and the preserved colloidal stability of the gold@PVOH-b-PNVCL NPs above the lower critical solution temperature (LCST) were confirmed by dynamic light scattering and turbidity measurements. The drug loading capacity (DLC of ca. 1.3–2.8 wt%) of the gold@PVOH-b-PNVCL NPs as a drug delivery system (DDS) was tested with Nadolol®, a hydrophilic drug, and the release behaviours were studied at several temperatures. PVOH-b-PNVCL copolymers with an LCST of a few degrees above the biological temperature (37 °C), for example, PVOH180-b-PNVCL110 (LCST of 41 °C), are preferential, due to the slower release at 37 °C, but a faster release at temperatures that are a few degrees higher. The cytocompatibility of the gold@PVOH-b-PNVCL NPs against mouse fibroblastic L929 cells was evaluated via the MTS assay. Cellular uptake within MEL-5 human melanoma cells was studied by confocal laser scanning microscopy, fluorescence-activated cell sorting and TEM techniques and it showed that gold@PVOH-b-PNVCL NPs preferably accumulated within the cellular cytoplasm, with an incubation concentration and period-dependent uptake process. All these results corroborated a general utility of these thermo-responsive gold@PVOH-b-PNVCL NPs for drug delivery and controlled drug release. [less ▲]

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See detail(Co)Polymerization of vinyl levulinate by cobalt-mediated radical polymerization and functionalization by ketoxime click chemistry
Allaoua, Imène; Eleuterio, Beatriz; Obadia, Mona M. et al

in Polymer Chemistry (2014), 5(8), 2973-2979

Vinyl levulinate is synthesized from levulinic acid by palladium-catalyzed vinyl exchange and is characterized by NMR and ESI-HRMS techniques. Homopolymerization of vinyl levulinate and random ... [more ▼]

Vinyl levulinate is synthesized from levulinic acid by palladium-catalyzed vinyl exchange and is characterized by NMR and ESI-HRMS techniques. Homopolymerization of vinyl levulinate and random copolymerization with vinyl acetate by cobalt-mediated radical polymerization affords well-defined ketone functionalized poly(vinyl ester)s. The impact of temperature, solvent and theoretical degree of polymerization on monomer conversion and control of the polymerization is studied by 1H NMR and size exclusion chromatography techniques. The ketoxime conjugation of O-benzylhydroxylamine with the pendant ketone functionality of poly(vinyl levulinate-co-vinyl acetate) is demonstrated. [less ▲]

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See detailElaboration of drug nanocarriers based on a glucosamine labeled amphiphilic polymer
Boyère, Cédric; Duhem, N; Debuigne, Antoine ULiege et al

in Polymer Chemistry (2014), 5(8), 3030-3037

A new functional polymer micelle with high loading efficiency of a poorly soluble drug was made of biocompatible and/or biosourced compounds, i.e. cholesterol-poly(ethylene glycol)-glucosamine (Chol-PEG ... [more ▼]

A new functional polymer micelle with high loading efficiency of a poorly soluble drug was made of biocompatible and/or biosourced compounds, i.e. cholesterol-poly(ethylene glycol)-glucosamine (Chol-PEG-GlcNH2). A synthesis strategy combining enzymatic and metal-free click chemistry was developed in order to meet the increasingly stringent requirements of biomedical applications. After the self-assembly of the Chol-PEG-GlcNH2 amphiphilic polymer in water, the presence of glucosamine at the micelle surface confers an active targeting moiety to the nanocarriers whereas protonation of the peripheral primary amine delay their aggregation. The complete characterization of this novel functional amphiphilic bioconjugate is presented as well as its aqueous solution behaviour and encapsulation efficiency using ketoconazole as a model hydrophobic drug. [less ▲]

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See detailGold nanorods coated with a thermo-responsive poly(ethylene glycol)-b-poly(N-vinylcaprolactam) corona as drug delivery systems for remotely near infrared-triggered release
Liu, Ji ULiege; Detrembleur, Christophe ULiege; De Pauw-Gillet, Marie-Claire ULiege et al

in Polymer Chemistry (2014), 5(3), 799-813

Poly(ethylene glycol)-b-poly(N-vinylcaprolactam) (PEG-b-PNVCL) copolymers are prepared from a PEG macro-chain transfer agent in DMF at 65 °C via reversible addition-fragmentation chain transfer (RAFT ... [more ▼]

Poly(ethylene glycol)-b-poly(N-vinylcaprolactam) (PEG-b-PNVCL) copolymers are prepared from a PEG macro-chain transfer agent in DMF at 65 °C via reversible addition-fragmentation chain transfer (RAFT) polymerization. The well-defined PEG114-b-PNVCL237 copolymer with a cloud point temperature of 39 °C is used for the formation of a thermo-responsive polymer corona on the surface of gold nanorods (GNRs) via a “grafting-to” approach. Thermo-responsiveness and thermo-dependent optical properties of the as-obtained GNR@PEG-b-PNVCL nanoparticles are studied with dynamic light scattering and UV/vis spectroscopy techniques. Near infrared (NIR)-induced heating of GNR@PEG-b-PNVCL is also explored in aqueous suspension under NIR laser irradiation (802 nm, up to 250 mW). The potential of these GNR@PEG-b-PNVCL nanoparticles to be used as smart drug delivery systems (DDS) is then studied. A hydrophilic drug model, Rhodamine ® B, is used to assess the guest loading capacity, and triggered release behaviours are then evaluated under conventional external heating or internal heating induced by remote NIR irradiation. Cytotoxicity evaluation of the GNR@PEG-b-PNVCL against the fibroblast-like L929 cell line is carried out via the MTS assay in order to confirm the improved biocompatibility of the GNRs after polymer coating. These thermo-responsive GNR@PEG-b-PNVCL nanoparticles are promising DDS that combine the chemotherapeutic and phototherapeutic functions. [less ▲]

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See detailReversibly crosslinked thermo- and redox-responsive nanogels for controlled drug release
Liu, Ji ULiege; Detrembleur, Christophe ULiege; Hurtgen, Marie ULiege et al

in Polymer Chemistry (2014), 5(1), 77-88

Reversibly crosslinked poly(vinyl alcohol)-b-poly(N-vinylcaprolactam) PVOH-b-PNVCL nanogels were prepared by using a redox-responsive crosslinking agent, 3,30-dithiodipropionic acid (DPA), to crosslink ... [more ▼]

Reversibly crosslinked poly(vinyl alcohol)-b-poly(N-vinylcaprolactam) PVOH-b-PNVCL nanogels were prepared by using a redox-responsive crosslinking agent, 3,30-dithiodipropionic acid (DPA), to crosslink the PVOH corona, above the lower critical solution temperature (LCST) of the PNVCL block. The stability of the as-prepared nanogels against heating and diluting with water was studied by dynamic light scattering (DLS) to follow the evolution of the hydrodynamic diameter and size distribution. Stability under reductive conditions was also studied by DLS and transmission electron microscopy (TEM) after exposure to dithiothreitol (DTT) buffer solutions at different pH. The reversibility of the crosslinking was evaluated by treating the de-crosslinked nanogels with hydrogen peroxide (H2O2) above the LCST. As a hydrophobic drug model, Nile red (NR) was loaded into the nanogels, and triggered release behaviours were studied after exposure to the same DTT buffer solutions. Moreover, two PVOH-b-PNVCL copolymers with different compositions and LCST were used to evaluate the effect of the LCST on the release behaviours of the nanogels. The cytotoxicity of the nanogels against a mouse fibroblast-like L929 cell line was assessed via the MTS assay, and preliminary studies on cellular uptake of the nanogels within human melanoma MEL-5 cells were also carried out by fluorescence microscopy and fluorescence-activated cell sorting. [less ▲]

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See detailNitroxide mediated polymerization of methacrylates at moderate temperature
Detrembleur, Christophe ULiege; Jérôme, Christine ULiege; De Winter, Julien et al

in Polymer Chemistry (2014), 5(2), 335-340

In this communication we report the first homopolymerization of a variety of methacrylates by an NMP process at moderate temperature (40–50 °C), using an easily accessible and inexpensive nitroxide ... [more ▼]

In this communication we report the first homopolymerization of a variety of methacrylates by an NMP process at moderate temperature (40–50 °C), using an easily accessible and inexpensive nitroxide precursor. The combination of a low temperature azo-initiator with a hindered nitroso-compound produces a mixture of hindered nitroxides in the polymerization medium that act as efficient polymerization control agents. Results of Electron Spin Resonance (ESR) spectroscopy experiments combined with mass spectrometric studies support the proposed in situ NMP mechanism. The hindered structure of the nitroxides formed in situ is believed to be responsible for the efficiency of the process by allowing it to proceed at low temperature, therefore limiting the side reactions generally observed in NMP of methacrylates. [less ▲]

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