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International audience; Epoxy vitrimers encompass many advantages compared to traditional epoxy materials such as recyclability, repairability, and reprocessability. These properties are induced by the incorporation of dynamic reversible covalent bonds. Recently, the incorporation of aromatic disulfide bridges that are dynamic has expanded the development of new eco-friendly epoxy materials. Herein, we studied a bio-based aliphatic disulfide based on cystamine as a hardener with a vanillin-derived bio-sourced epoxy to prepare fully bio-based epoxy vitrimers. This article provides a comparative study between cystamine and an aromatic disulfide benchmark hardener issued from petrol resources. This work demonstrated that the presence of this aliphatic hardener has a significant influence not only on the reactivity, but most importantly on the resulting dynamic properties. An interesting yet counterintuitive accelerating effect of the dynamic exchanges was clearly demonstrated with only 2 to 20% of molar fraction of cystamine added to the aromatic disulfide formulation. A similar glass transition was obtained compared to the purely aromatic analogue, but relaxation times were decreased by an order of magnitude.

The use of reactive diluents is undeniably of paramount importance to develop epoxy resins which would meet more demanding and restrictive processes and applications in terms of viscosity and glass transition temperature.

Functional polymers, such as poly(ethylene glycol) (PEG) terminated with a single phosphonic acid, hereafter PEGik-Ph are often applied to coat metal oxide surfaces during post synthesis steps, but are not sufficient to stabilize sub-10 nm particles in protein-rich biofluids. The instability is attributed to the weak binding affinity of post-grafted phosphonic acid groups, resulting in a gradual detachment of the polymers the surface. Here, we assess these polymers as coating agents using an alternative route, namely the one-step wet-chemical synthesis, where PEGik-Ph is introduced with cerium precursors during the synthesis. Characterization of the coated cerium oxide nanoparticles indicates a core-shell structure, where the cores are 3 nm cerium oxide and the shell consists of functionalized PEG polymers in a brush configuration. Results show that cerium oxide nanoparticles coated with PEG1k-Ph and PEG2k-Ph are of potential interest for applications as nanomedicine due to their high Ce(III) content and increased colloidal stability in cell culture media. We further demonstrate that the cerium oxide nanoparticles in the presence of hydrogen peroxide show an additional absorbance band in the UV-vis spectrum, which is attributed to Ce-O22- peroxo-complexes and could be used in the evaluation of their catalytic activity for scavenging reactive oxygen species., 21 pages, 7 figures

Optical in vivo imaging has become a widely used technique and is still under development for clinical diagnostics and treatment applications.

International audience; In the nanomedicine field, there is a need to widen the availability of nanovectors to compensate for the increasingly reported side effects of poly(ethene glycol). Nanovectors enabling cross-linking can further optimize drug delivery. Cross-linkable polyoxazolines are therefore relevant candidates to address these two points. Here we present the synthesis of coumarin-functionalized poly(2-alkyl-2-oxazoline) block copolymers, namely, poly(2-methyl-2-oxazoline)-block-poly(2-phenyl-2-oxazoline) and poly(2-methyl-2-oxazoline)-block-poly(2-butyl-2-oxazoline). The hydrophilic ratio and molecular weights were varied in order to obtain a range of possible behaviors. Their self-assembly after nanoprecipitation or film rehydration was examined. The resulting nano-objects were fully characterized by transmission electron microscopy (TEM), cryo-TEM, multiple-angle dynamic and static light scattering. In most cases, the formation of polymer micelles was observed, as well as, in some cases, aggregates, which made characterization more difficult. Cross-linking was performed under UV illumination in the presence of a coumarin-bearing cross-linker based on polymethacrylate derivatives. Addition of the photo-cross-linker and cross-linking resulted in better-defined objects with improved stability in most cases.

International audience; Photo-crosslinked shape-memory polymer (SMP) materials were obtained by the copolymerization of methacrylates bearing 2-ethylhexyl plasticizing group (EHMA) and photoactive coumarin unit (CoumMA). The photo-dimerization of coumarin units ensured the crosslinking of P(EHMA-co-CoumMA) and further allowed the fabrication by stereolithography of well-defined butterfly with ribbed wings to illustrate the potential of promising coumarin chemistry in additive fabrication. The influence of dye ratio on the optical and the mechanical properties of the transparent P(EHMA-co-CoumMA) films as well as the shape memory properties of the films in unfolding and twisting deformations were detailed and demonstrate the opportunity of coumarin-bearing photoprintable polymers for 4D printing.

Beyond the need to find a non-toxic alternative to DiGlycidyl Ether of Bisphenol-A (DGEBA), the serious subject of non-epichlorohydrin epoxy resins production remains a crucial challenge that must be solved for the next epoxy resin generations. In this context, this study focuses on the valorization of vegetable oils (VOs) into thermoset materials by using (i) epoxidation of the VOs through the “double bonds to epoxy” synthetic route and (ii) synthesis of crosslinked homopolymers by UV or hardener-free thermal curing processes. A thorough identification, selection and physico-chemical characterization of non-edible or non-valuated natural vegetable oils were performed. Selected VOs, characterized by a large range of double bond contents, were then chemically modified into epoxides thanks to an optimized, robust and sustainable method based on the use of acetic acid, hydrogen peroxide and Amberlite® IR-120 at 55 °C in toluene or cyclopentyl methyl ether (CMPE) as a non-hazardous and green alternative solvent. The developed environmentally friendly epoxidation process allows reaching almost complete double bond conversion with an epoxy selectivity above 94% for the 12 studied VOs. Finally, obtained epoxidized vegetable oils (EVOs), characterized by an epoxy index from 2.77 to 6.77 meq. g−1 were cured using either UV or hardener-free thermal curing. Both methods enable the synthesis of 100% biobased EVO thermoset materials whose thermomechanical performances were proved to linearly increase with the EVOs' epoxy content. This paper highlights that tunable thermomechanical performances (Tα from −19 to 50 °C and Tg from −34 to 36 °C) of EVO based thermoset materials can be reached by well selecting the starting VO raw materials.

In this feature article, we provide an overview of our research on statistical copolymers as a coating material for metal oxide nanoparticles and surfaces. These copolymers contain functional groups enabling non-covalent binding to oxide surfaces and poly(ethylene glycol) (PEG) polymers for colloidal stability and stealthiness. The functional groups are organic derivatives of phosphorous acid compounds R-H$_2$PO$_3$, also known as phosphonic acids that have been screened for their strong affinity to metals and their ability to build multidentate binding. Herein we develop a polymer-based coating platform that shares features with the techniques of self-assembled monolayers (SAM) and Layer-by-Layer (L-b-L) deposition. The milestones of this endeavor are the synthesis of PEG-based copolymers containing multiple phosphonic acid groups, the implementation of simple protocols combining versatility with high particle production yields and the experimental demonstration of the colloidal stability of the coated particles. As a demonstration, coating studies are conducted on cerium (CeO$_2$), iron ($\gamma$-Fe$_2$O$_3$), aluminum (Al$_2$O$_3$) and titanium (TiO$_2$) oxides of different sizes and morphologies. We finally discuss applications in the domain of nanomaterials and nanomedicine. We evaluate the beneficial effects of coating on redispersible nanopowders, contrast agents for In Vitro/Vivo assays and stimuli-responsive particles., Comment: 28 pages 10 figures, accepted at Langmuir as Invited Feature Article

Oxidative stress, which is one of the main harmful mechanisms of pathologies including is-chemic stroke, contributes to both neurons and endothelial cell damages, leading to vascular lesions. Although many antioxidants have been tested in preclinical studies, no treatment is currently available for stroke patients. Since cerium oxide nanoparticles (CNPs) exhibit remarkable antioxidant capacities, our objective is to develop an innovative coating to enhance CNPs biocompatibility without disrupting their antioxidant capacities or enhance their toxicity. This study reports the synthesis and characterization of functional polymers and their impact on the enzyme-like catalytic activity of CNPs. To study the toxicity and the antioxidant properties of CNPs for stroke and particularly endothelial damages, in vitro studies are conducted on a cerebral endothelial cell line (bEnd.3). Despite their internalization in bEnd.3 cells, coated CNPs are devoid of cytotoxicity. Microscopy studies report an intracellular localization of CNPs, more precisely in endosomes. All CNPs reduces glutamate-induced intracellular production of ROS in endothelial cells but one CNP significantly reduces both the production of mitochondrial super-oxide anion and DNA oxidation. In vivo studies report a lack of toxicity in mice. This study there-fore describes and identifies biocompatible CNPs with interesting antioxidant properties for ischemic stroke and related pathologies., 27 pages 9 figures

The combination of multiple functionalities in a single material is an appealing strategy for the de-velopment of smart materials with unique features. In this work, we present the preparation of thermoresponsive magnetic nanoparticles and their one-dimensional assembly into transient micro-filaments. The material is based on 9.4 nm iron oxide nanoparticles grafted with poly(N-n-propylacrylamide) via multiphosphonic acid anchoring sites. The hybrid nanoparticles present a low critical solution temperature (LCST) transition between 21 {\deg}C and 28 {\deg}C, depending on the pH and the ionic strength. When heated above the LCST in defined conditions, the nanoparticles ag-gregate and respond to an external magnetic field. An intrinsic characteristic of the thermorespon-sive particles is an asymmetric transition between cooling and heating cycles, that was favorably exploited to build one-dimensional permanent microstructures, such as magnetic microfilaments and cilia. In summary, we present the development of a nanoplatform responsive to multiple stimu-li, including temperature, magnetic field, pH and ionic strength and its transformation into magneti-cally active microfilaments that could find potential applications in remotely controlled devices., Comment: 18 pages, 8 figures

Bio-epoxy resins based on five epoxidized vegetable oils were formulated with an aromatic disulfide crosslinker with diacid functionality, 2,2′-dithiodibenzoic acid (DTBA), to obtain recyclable epoxy thermosets. Flax fibres (FF) and PLA woven were used as bio-based reinforcements for these matrices. Different percentages of reinforcement were tested and the effect of the natural fibres on the matrix's crosslinking reaction was studied by DSC analysis. Then, the obtained materials were analyzed by Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), Dynamic Mechanical Analysis (DMA), water absorption and Scanning Electron Microscopy (SEM). The reinforcements improved the thermal and mechanical properties of the neat resins, with tan δ values varying from 91 to 148 °C showing a good compatibility matrix-FF but a reduced one in case of matrix-PLA woven. The dynamic nature of the networks crosslinking allowed the chemical and mechanical recycling of both resins and bio-composites. Moreover, the obtained results show the possibility to recuperate the natural FF filler for the preparation of second-life generation bio-composites.

International audience; Bio-inspired materials are commonly used in the development of functional devices. The fabrication of artificial cilia mimicking the biological functions has emerged as a promising strategy for fluid manipulation in miniaturized systems. In this study, we propose a different physicochemical insight for the preparation of magnetic cilia based on the temperature-triggered reversible assembly of coated iron oxide nanoparticles in a biocompatible template-free approach. The length of the prepared cilia could be tuned between 10-100 µm reaching aspect ratios up to 100 in a very dense array of flexible structures with persistence lengths around 8 µm. Magnetic actuation of the cilia revealed robust structures (over several hours of actuation) with a wide range of bending amplitudes resulting from high susceptibility of the filaments. The results demonstrate that the proposed strategy is an efficient and versatile alternative for templated fabrication methods and producing cilia with remarkable characteristics and dimensions within the template-free approaches.

International audience; The preparation of thermosets based on epoxidized vegetable oils (EVOs) involved a peculiar attention in recent years; however, most of them cannot be recycled once cross-linked. In the present work, epoxy thermosetting resins like-vitrimers with dynamic disulfide covalent bonds were prepared by copolymerizing twelve EVOs with 2,2′-dithiodibenzoic acid, as hardener. Here, we show for the first time the reprocessability, repairability, and recyclability properties of EVOs thermosets. The 3R abilities were evaluated in correlation with the EVO epoxy contents, which influence the final thermo-mechanical properties of the recycled material. The virgin versus recycled materials' comparison was studied by FT-IR, DSC, TGA, and DMA, also comparing their swelling ability and high gel content. The study investigates, in addition, the excellent shape memory properties of the reprocessed EVOs/disulfide materials.

Epoxy resins are widely used in the composite industry due to their dimensional stability, chemical resistance, and thermo-mechanical properties. However, these thermoset resins have important drawbacks. (i) The vast majority of epoxy matrices are based on non-renewable fossil-derived materials, and (ii) the highly cross-linked molecular architecture hinders their reprocessing, repairing, and recycling. In this paper, those two aspects are addressed by combining novel biobased epoxy monomers derived from renewable resources and dynamic crosslinks. Vanillin (lignin) and phloroglucinol (sugar bioconversion) precursors have been used to develop bi- and tri-functional epoxy monomers, diglycidyl ether of vanillyl alcohol (DGEVA) and phloroglucinol triepoxy (PHTE) respectively. Additionally, reversible covalent bonds have been incorporated in the network by using an aromatic disulfide-based diamine hardener. Four epoxy matrices with di erent ratios of epoxy monomers (DGEVA/PHTE wt%: 100/0, 60/40, 40/60, and 0/100) were developed and fully characterized in terms of thermal and mechanical properties. We demonstrate that their performances are comparable to those of commonly used fossil fuel-based epoxy thermosets with additional advanced reprocessing functionalities. This project has received funding from the Bio Based Industries Joint Undertaking under the European Union’s Horizon 2020 research and innovation program under grant agreement No 744311

Cerium oxide nanoparticles have been shown to mimic oxidoreductase enzymes by catalyzing the decomposition of organic substrates and reactive oxygen species. This mimicry can be found in superoxide radicals and hydrogen peroxides, harmful molecules produced in oxidative stress asso-ciated diseases. Despite the fact that nanoparticle functionalization is mandatory in the context of nanomedicine, the influence of polymer coatings on their enzyme-like catalytic activity is poorly understood. In this work, six polymer coated cerium oxide nanoparticles are prepared by associa-tion of 7.8 nm cerium oxide cores with two poly(sodium acrylate) and four poly(ethylene glycol) (PEG) grafted copolymers with different terminal or anchoring end groups, such as phosphonic acids. The superoxide dismutase-, catalase-, peroxidase- and oxidase-like catalytic activities of the coated nanoparticles were systematically studied. It is shown that the polymer coatings do not af-fect the superoxide dismutase-like, impair the catalase-like and oxidase-like and surprisingly im-proves peroxidase-like catalytic activities of cerium oxide nanoparticles. It is also demonstrated that the particles coated with the PEG-grafted copolymers perform better than the poly(acrylic acid) coated ones as oxidoreductase-like enzymes, a result that confirms the benefit of having phosphon-ic acids as anchoring groups at the particle surface., Comment: 23 pages, 8 figures, 3 tables

International audience; Bisphenol A based epoxy thermosets involve both environmental and health risks. By reacting a vegetal oil-based epoxide with an aromatic diacid containing S-S bonds a thermoset is produced. Herein, reprocessable thermosets were synthesized, the recyclability being designed through a dual mechanism: that of disulfide metathesis and of transesterifications. To assess the feasibility of the reprocessing, a series of ten initiators were tested to probe their effect not only on the crosslinking reaction but also on the recyclability. This study introduces for the first time the key role of the initiator on the material performances and on their reprocessing. A very good reprocessability was obtained for thermosets prepared using as initiator the imidazole. Moreover, the thermosets exhibit complete chemical recyclability in 1N NaOH at 80 °C, after 3 days, without needing additional chemicals. The reprocessed materials have similar performances with the virgin ones, even after 10 cycles of reprocessing.

International audience; In a sustainable development context, epoxidized vegetable oils (EVO) have unlimited and promising future prospects as renewable and environmentally friendly feedstock. The only drawback to their use is their low and non-selective reactivity compared to the aromatic epoxides. Properly, a small optimized amount of "true" initiators can overcome this issue and also beneficially serve in properties such as glass transition, modulus, strength, elongation at break, and chemical resistance. This paper presents efforts to understand and identify the initiator's effect to more accurately predict how to select a good initiator on EVO/dicarboxylic acid systems. A new bio-based reprocessable epoxy resin was prepared from epoxidized linseed oil (ELO) and 2,2′-dithiodibenzoic acid (DTBA). The evolution of the chemical structures and the reactions' mechanisms have been systematically studied by in situ Fourier transform infrared (FT-IR) and nuclear magnetic resonance (NMR) spectroscopies and differential scanning calorimetry (DSC). A screening of 10 initiators was performed for the ELO/DTBA cross-linking reaction. The influence of the initiator's structure, basicity, and nucleophilicity was assessed and ranked in terms of the kinetic response including the epoxy− acid reaction rate and the percentage of functional group consumption. An excellent effect achieved by imidazole as an initiator was demonstrated. An attempt has been proposed to corroborate the experimental values with the results of quantum chemistry calculations.

International audience; For the first time, the effect of reactant structure, stoichiometry and heating rate on the reactivity of epox-idized perilla oil (EPLO) and epoxidized safflower oil (ESFO) with dicarboxylic acids (DCAs) was studied using in situ FT-IR. The epoxy content in the monomer structure was found to affect the copolymeriza-tion system's reactivity, with epoxidized linseed oil (ELO) considered as a reference. In this study we discuss also the influence of the DCA structure on the copolymerization reactivity. Two aromatic diacids, dithiodibenzoic acid (DTBA) and diphenic acid (DPA), were studied and compared in the copolymerization of the 3 EVOs, in the presence of imidazole (IM) initiator. The kinetics of these reactions were followed by in situ FT-IR. The corresponding activation energies were calculated via different kinetic models. These data highlight the higher reactivity of the EPLO monomer and the DTBA hardener.

Bio-inspired materials are commonly used in the development of functional devices. The fabrication of artificial cilia mimicking the biological functions has emerged as a promising strategy for fluid manipulation in miniaturized systems. In this study, we propose a different physicochemical insight for the preparation of magnetic cilia based on the temperature-triggered reversible assembly of coated iron oxide nanoparticles in a bio-compatible template-free approach. The length of the prepared cilia could be tuned between 10 and 100 microns reaching aspect ratios up to 100 in a very dense array of flexible structures with persistence lengths around 8 microns. Magnetic actuation of the cilia revealed robust structures (over several hours of actuation) with a wide range of bending amplitudes resulting from high susceptibility of the filaments. The results demonstrate that the proposed strategy is an efficient and versatile alternative for templated fabrication methods and producing cilia with remarkable characteristics and dimensions within the template-free approaches., Comment: 15 pages 5 figures

International audience; The end-of-life of thermoset materials is a real issue that confronts our society, and the strategy of introducing dynamic reversible bonds can be a sustainable solution to overcome this problem. This study shows an efficient way to produce biobased and recyclable thermosets, for a circular use. To reduce the production costs linked to energy and duration, an improved curing process is proposed by combining aromatic and aliphatic diacid hardeners containing dynamic S−S bonds. The work demonstrates the increased reactivity of epoxidized vegetable oil reacted with the two diacids. The structural evolutions during the exchange reactions that allow the recyclability were followed by Fourier transformed-infrared and nuclear magnetic resonance spectroscopies, high-performance liquid chromatography, and mass spectroscopy. The curing process was studied by differential scanning calorimetry and kinetic study.

Even though the hydrosilylation reaction has been the method of choice to produce organosilicon compounds for 70 years, improving its selectivity still remains a current challenge. In this work, a comprehensive study of the influence of experimental parameters on hydrosilylation side reactions was undertaken by applying a fractional factorial design of experiments. The study was conducted for polyethylene glycol (PEG, 1000 g mol−1) terminated allyl ether, which is commonly employed as a reactive functional group toward hydrosilylation. In addition, the resulting silane-functionalized PEG happens to be a molecule of interest in various domains such as the biomedical, cosmetic or food industry thanks to its properties in accordance with these sectors' requirements. This methodology enables highlighting an optimized combination of experimental parameters as well as a cause–effect relationship between the different side reactions, leading to a better control of the hydrosilylation reaction.

This paper reports the synthesis of epoxy functionalized bio-renewable monomers that can be applied in cationic photopolymerization. The cationic UV-curing process was efficient giving rise to crosslinked coatings with a wide range of thermo-mechanical properties. The final properties were analysed based on the monomer chemical structure.

Whether it is for imparting anti-corrosion, anti-fogging or stable optical properties, hydrophobic coatings have been at the center of numerous research studies these last few decades. While surface perfluorination and surface roughening have been thoroughly studied, few studies discuss the introduction of fluoroalkylsilanes (FASs) directly into sol–gel networks in order to obtain water-repellent silica films. The latter method, referred to as co-condensation, is yet easier to perform (one-pot and mild conditions) and in accordance with industrial standards. However, so far its implementation to achieve maximum surface hydrophobicity has not been well-controlled and the influence of such FAS molecules trapped in the sol–gel network on the mechanical properties has not been investigated. In this work, how the co-condensation method affects the distribution of the fluorinated additives in the sol–gel network is studied by obtaining a precise XPS profile of the FASs within the material. The water-repellent, optical and mechanical properties of such coatings were evaluated. From these results, the one-step co-condensation method was proved to exhibit similar properties to a classic multi-step surface silanization. Moreover, by getting a better understanding of the mechanisms involved during the film formation, it is henceforth possible to accurately control the concentration of FASs needed to optimize the water-repellency. Besides, it was demonstrated that these results were not impacted by the chemical structure of the FASs, thus highlighting various alternative synthesis strategies of interest. Based on these conclusions, the co-condensation is, for the first time, demonstrated to be a method of choice to prepare water-repellent sol–gel coatings, presenting the significant advantage compared to classic silanization to allow an accurate adjustment of the FAS concentration in order to achieve maximum hydrophobicity.

The work presented here describes new UV-crosslinkable thin layer polymeric materials for the encapsulation of ZnO nanowires (NWs) in multi-NWs pressure based fingerprint sensors. Such innovative sensor is a novel technology for fingerprint capture developed within the PiezoMAT FP7 European project. The sensing principle is based on the piezoelectric property of ZnO NWs, on which a potential difference is generated when they undergo compression and/or bending forces. Since the pressure induced by the finger cannot be directly applied on the NWs, the deformation is applied through a polymeric material that aims at transferring forces from the finger onto the array of NWs without altering their integrity. Besides, since it is dedicated to be in direct contact with human finger or oil pollutants, the encapsulation layer must also exhibit chemical inertness, as well as hydrophobicity and oleophobicity.

SPECIFIC POLYMERS is a SME acting as R&D service provider in the field of functional monomers, polymers and materials with high specificity. In more than 12 years, SP has developed the synthesis of more than 1000 functional building blocks, monomers and polymers and is now working with more than 400 customers and partners in more than 30 countries worldwide in all field of applications such as surface finishing (glass, metal, metal oxides, nanoparticles, plastics), aeronautic, automotive, pharmaceutical industry, cosmetic, electronic, optic, energy (fuel cells, solar cells or lithium batteries). Since 2013, SP is developing innovative materials for electronic devices. As for example, SP is involved in PiezoMAT European Project and develops UV-crosslinkable thin layer polymeric materials for the encapsulation of ZnO nanowires (NWs) in multi-NWs pressure based fingerprint sensors.

To estimate the potential of ZnO nanostructures for force sensing applications, arrays of single nanowires and arrays of nanowire bundles have been fabricated by wet chemical growth method. The piezoelectrical and electrical properties of the single nanowires have been investigated by atomic force microscopy based techniques. The piezoelectric constant d(33) = 15 pm/V has been determined from vibration analyses. The electrical response in the range up to 400 fA upon applying force between 40 nN and 1 mu N has been recorded. The nanowire bundles were studied by electro-mechanical macro probing technique within the force range 1 - 10 mN, where a reproducible response in pA range has been measured.

The use of functional polymers for the sorption of metallic species in water was widely practiced in treatment processes. Such sorbents offered the possibility to remove a large range of metals because of the variety of possible functional groups on polymeric backbones. In particular, acidic groups (carboxylic, phosphonic or sulfonic groups) proved to be of great interest for the sorption of different cations. Sorption efficiency and selectivity through complexation or ion exchange interactions were directly linked to the nature of both the functional groups and the cationic metallic ions. In addition, the physical nature of materials was another important parameter that had to be considered. Depending on the polymer solubility, the cross-linking density, and the polymeric architecture, significant differences regarding sorption properties were observed in the sorption kinetics. Thus, it was challenging to select the appropriate polymeric sorbent with the most relevant physical nature and functionality in the area of wastewater treatment. This review aims at reporting organic polymeric materials bearing acidic groups able to interact (selectively or not) with metallic cations. Both synthetic and bio-based materials were reviewed and main parameters that had to be considered when choosing functional organic sorbents for the removal of metallic pollution were highlighted. Finally, recyclability of the polymeric sorbents was also considered.

We report on the synthesis, characterization, stability and pharmacokinetics of novel iron based contrast agents for magnetic resonance imaging (MRI). Statistical copolymers combining multiple phosphonic acid groups and poly(ethylene glycol) (PEG) were synthesized and used as coating agents for 10 nm iron oxide nanocrystals. In vitro, protein corona and stability assays show that phosphonic acid PEG copolymers outperform all other coating types examined, including low molecular weight anionic ligands and polymers. In vivo, the particle pharmacokinetics is investigated by monitoring the MRI signal intensity from mouse liver, spleen and arteries as a function of the time, between one minute and seven days after injection. Iron oxide particles coated with multi-phosphonic acid PEG polymers are shown to have a blood circulation lifetime of 250 minutes, i.e. 10 to 50 times greater than that of recently published PEGylated probes and benchmarks. The clearance from the liver takes in average 2 to 3 days and is independent of the core size, coating and particle stability. By comparing identical core particles with different coatings, we are able to determine the optimum conditions for stealth MRI probes., Comment: 19 pages 8 figures, RSC Advances, 2016

International audience; This study reports on a new process for the removal and recovery of metal elements from wastewaters, associating a sorption step on a thermosensitive copolymer bearing phosphonic acid moieties, namely the poly(N-n-propylacrylamide-stat-hydrolyzed (dimethoxyphosphoryl)methyl 2-methylacrylate) (P(NnPAAm-stat-hMAPC1)), with a separation step by filtration. The phosphonic acid groups enable high sorption capacities for multi-component solutions (Ca2+, Ni2+, Cd2+, Al3+), while the thermosensitive behavior of the polymer allows, for temperatures higher than its LCST (25.6 °C), to get copolymer–cations non soluble particles. In the presence of aluminum, which was shown to have simultaneous coagulationand neutralization actions, these particles form aggregates of mean diameter 27–63 µm easily removed by conventional filtration (pore diameter >10 µm), leading to a lower energetic separation process compared with the well-known Polymer Enhanced Ultrafiltration (PEUF) Process. To recover metal ions and regenerate the thermosensitive copolymer sorbent, an acidic (H2SO4) regeneration step was studied. A decrease of the regeneration solution pH from 4 to 1 led to 100% desorption when the pH was set to 1. Such low pH conditions simultaneously allowed (i) a decrease of the copolymer LCST down to 19.5 °C, and (ii) to reach the isoelectric point of copolymer particles to finally lead to the formation ofregenerated copolymer particles which could be recovered by filtration and reused in additional sorption–filtration cycles without any loss of sorption capacities.

Congrès sous l’égide de la Société Française de Génie Biologique et Médical (SFGBM); National audience; For nanomedicine applications, there is a need to design advanced and cost-effective coatings, resistant to protein adsorption leading to increased biodistribution in vivo. In this study, phosphonate poly(ethylene glycol) copolymers were synthesized and used to coat 6nm and 13nm iron oxide particle. In vitro, PEGylated particles exhibit exceptional stability and low cellular uptake, of the order of 100 femtograms of iron per cell. In vivo, we developed an in vivo Dynamic Susceptibility Weighted MRI (7T) protocol to monitor the hepatic capture and clearance of the particles injected to mice as a function of the time. PEGylated coat of molecular weight 2000 gmol-1 show a 2hrs delay to liver uptake as compared to the commercially available USPIO Cliavist, indicating a direct correlation between the surface properties of the contrast agents and their stealthiness.

When disperse in biological fluids, engineered nanoparticles are selectively coated with proteins, resulting in the formation of a protein corona. It is suggested that the protein corona is critical in regulating the conditions of entry into the cytoplasm of living cells. Recent reports describe this phenomenon as ubiquitous and independent of the nature of the particle. For nanomedicine applications however, there is a need to design advanced and cost-effective coatings that are resistant to protein adsorption and that increase the biodistribution in vivo. In this study, phosphonic acid poly(ethylene glycol) copolymers were synthesized and used to coat iron oxide particles. The copolymer composition was optimized to provide simple and scalable protocols as well as long-term stability in culture media. It is shown that polymers with multiple phosphonic acid functionalities and PEG chains outperform other types of coating, including ligands, polyelectrolytes and carboxylic acid functionalized PEG. PEGylated particles exhibit moreover exceptional low cellular uptake, of the order of 100 femtograms of iron per cell. The present approach demonstrates that the surface chemistry of engineered particles is a key parameter in the interactions with cells. It also opens up new avenues for the efficient functionalization of inorganic surfaces., 21 page, 7 figures,Biomacromolecules 2014

International audience; The present contribution deals with the ease of controlling the thermosensitivity of statistical copolymers prepared by free radical polymerization playing on the reactivity ratios of both monomers used for the synthesis. The copolymers were prepared using N-n-propylacrylamide (NnPAAm) monomer to achieve the thermoresponsive properties. The second monomer was either (dimethoxyphosphoryl)methyl 2-methylacrylate (MAPC1) or diethyl 2-(acrylamido)ethylphosphonate (DAAmEP) in order to incorporate phosphonic acid moieties after hydrolysis. The architecture of these original statistical copolymers was determined by measuring the reactivity ratios of both (NnPAAm/MAPC1) and (NnPAAm/DAAmEP) monomer couples. By varying the chemical nature of the phosphonated-based monomer (methacrylate or acrylamide), it was possible to get different reactivity ratios, and as a consequence to significantly affect the thermosensitive behavior of the statistical copolymers for a constant proportion of phosphonic acid groups. Additionally, all copolymers showed similar sorption rates toward nickel cations (Ni2+).

International audience; Reversible addition-fragmentation chain-transfer (RAFT) polymerization of dimethyl(methacrylamido) dodecylphosphonate (DMADP-(OMe)2), a new long alkyl chain methacrylamide monomer bearing phosphonated diester groups and originating from undecylenic acid, was successfully achieved in the presence of a dithioester or a trithiocarbonate chain transfer agent (CTA). Polymers with various molecular weights and low dispersities (Đ < 1.3) were obtained in a controlled way. Then, amphiphilic polymers were produced after selective hydrolysis of phosphonated diester moieties. Finally, dynamic light scattering (DLS), transmission electron microscopy (TEM) and atomic force microscopy (AFM) measurements were performed on the corresponding phosphonic diacid amphiphilic polymers showing that they were able to self-assemble in water and in organic solvent (acetonitrile), forming particles with hydrodynamic diameters of 2600 and 470 nm, respectively. By using 1H diffusion ordered spectroscopy NMR (1H DOSY NMR), these objects were found to possess a sharp interphase with very short mobile "hair" on their surface.

In this paper, original thermosensitive copolymers bearing phosphonic acid groups, namely the poly(N-n-propylacrylamide-stat-2-(methacryloyloxy)methylphosphonic acid) (P(NnPAAm-stat-hMAPC1)) were synthesized, and their sorption properties for three divalent cations (Ni(2+), Ca(2+), Cd(2+)) and one trivalent cation (Al(3+)) have been investigated. The sorption experiments were performed with increasing relative amount of cationic pollution compared to the amount of sorption sites (C(n+)/P ratio) in mono and multi-component solutions to investigate the sorption mechanisms. C(n+)/P proved to strongly affect the sorption capacity and high capacities were obtained for all cations at highest C(n+)/P ratios, reaching one mole of C(sorbed)(n+) per phosphonated moiety. For divalent cations, sorption mechanisms were likely to be described by electrostatic interactions only, whereas for aluminum trivalent cation the sorption not only resulted from electrostatic interactions but also from the formation of coordination binding. The selectivity of the phosphonic acid moieties for aluminum cations was demonstrated, highlighting the interest of P(NnPAAm-stat-(h)MAPC1) for their use for the treatment of metallic pollution from wastewater.

International audience; In this work, new thermosensitive copolymers bearing phosphonated groups were synthesized and used to remove metal pollution. Sorption properties are brought by hydrolysed (dimethoxyphosphoryl)methyl 2-methylacrylate (hMAPC1) monomer. N-n-propylacrylamide (NnPAAm) led to the thermoresponsive properties of the copolymers. Low Lower Critical Solution Temperature (LCST) values were observed, ranging between 20 °C and 25 °C depending on the molar ratio of each monomer in the copolymer. Sorption properties of these copolymers toward nickel ions were evaluated for increasing temperatures (10 to 40 °C), Ni ions concentrations of 20 mg.L-1 and pH values between 3 and 7. Best results were observed for temperatures just lower than the LCST (20 °C), when the copolymer was fully soluble in water solution. For temperature higher than the LCST, phosphonic diacid groups accessibility was considerably reduced by the precipitation of the thermosensitive part of the copolymer leading to lower sorption properties. In these conditions, the highest Ni removal by the copolymer was observed for pH = 7, when there was almost no competition between the sorption of H+ and Ni2+ ions on the phosphonic acid groups. These optimal conditions enabled to remove about 70% of the Nickel in the synthetic effluent.

In order to remove metal ions from wastewaters, thermosensitive copolymers bearing sorption properties toward metal cations were prepared by free radical copolymerization between the N- n -propylacrylamide (N n PAAm) and the (dimethoxyphosphoryl)methyl 2-methylacrylate (MAPC1), followed by a hydrolysis of the phosphonated esters into phosphonic diacid groups ( h MAPC1). The thermosensitivity and the sorption abilities of the resulting poly(N n PAAm- stat - h MAPC1) copolymers were studied. Lower Critical Solution Temperatures (LCST) of these copolymers ranged from 22 °C to 26 °C, depending on the molar ratio of phosphonated monomers and were lower than those obtained with usual poly(N- iso propylacrylamide)-based polymers. The influence of both the temperature and the pH on the sorption properties of the copolymers was evaluated for Ni 2+ cations. The most interesting results were obtained for temperatures around the LCST, i.e. when the proximity of the complexing groups favored the sorption of metallic cations. Concerning the pH effect, the maximum sorption capacity was obtained at pH 7, i.e. in the absence of competition between the sorption of H + and Ni 2+ ions on the phosphonic acid groups. The influence of the molar ratio of metal ions and phosphonate moieties was also studied and different sorption mechanisms were proposed.

International audience; The present contribution reports on the synthesis and controlled polymerization of a novel acrylamide monomer containing phosphonated moieties, namely diethyl-2-(acrylamido)ethylphosphonate. This monomer appears to be of great interest due to the phosphonated moieties, which can lead to a wide range of applications, associated with the chemical stability of the acrylamide compared to more common (meth)acrylate monomers. Reversible Addition-Fragmentation Transfer (RAFT) polymerization of this monomer was investigated using two different trithiocarbonate chain transfer agents, and it allowed the synthesis of poly(diethyl-2-(acrylamido)ethylphosphonate) with controlled molecular weight and low dispersity. Additionally, a diblock copolymer was successfully prepared by a similar RAFT procedure using thermosensitive poly(N-n-propylacrylamide) as a macro-chain transfer agent. A combination of both stimuli-responsive and phosphonated ester or phosphonic diacid (after hydrolysis) containing blocks appears valuable for drug delivery or water treatment, for instance.

International audience; This Review is focused on the growing interest brought to phosphorus-containing organic materials for applications in the biomedical field, mainly because of their properties such as biocompatibility, hemocompatibility, and protein adsorption resistance. It mainly describes relevant works achieved on these materials for various applications: dentistry, regenerative medicine, and drug delivery. Special attention was given to 2-methacryloyloxyethyl phosphorylcholine (MPC) monomer as the latter appeared of great importance because of its biomimetic structure due to the presence of the phospholipid group on its structure. As a result, much research effort is currently concentrated on the development of phosphorylcholine- containing (co)polymers that represent a promising class of materials.