C. Labrugère

University of Bordeaux, Burdeos, Aquitaine, France

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Publications (101)230.81 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: AFM of high density polyethylene Virgin Direct fluorination, 20 °C C4F8 plasma, 25 °C CF4 plasma, 90 °C.
    Journal of Fluorine Chemistry 09/2014; · 1.94 Impact Factor
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    ABSTRACT: Well crystallized VO2 (A) microrods were grown via a single step hydrothermal reaction in the presence of V2O5 and oxalic acid. With the advantage of high crystalline samples, we propose P4/ncc as an appropriate space group at room temperature. From morphological studies, we found that the oriented attachment and layer by layer growth mechanisms are responsible for the formation of VO2 (A) micro rods. The structural and electronic transitions in VO2 (A) are strongly first order in nature, and a marked difference between the structural transition temperatures and electronic transitions temperature was evidenced. The reversible intra- (LTP-A to HTP-A) and irreversible inter- (HTP-A to VO2 (M1)) structural phase transformations were studied by in-situ powder X-ray diffraction. Attempts to increase the size of the VO2 (A) microrods are presented and the possible formation steps for the flower-like morphologies of VO2 (M1) are described.
    Journal of Solid State Chemistry 01/2014; · 2.04 Impact Factor
  • Solid State Sciences. 11/2013;
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    ABSTRACT: Oh my Gold! Gold atoms stabilise catalytically active palladium nanoparticles when engaged in an alloy heterogenised on carbon. The increased durability makes the Pd-Au/C catalyst more recyclable than the gold-free Pd/C catalyst for the Sonogashira reaction.
    Chemistry 10/2013; 19(42):14024-14029. · 5.93 Impact Factor
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    ABSTRACT: Thin films of WO3 were prepared by surfactant assisted spray pyrolysis on F-doped SnO2 (FTO) conductive glass by using hexadecyltrimethylammonium bromide (HTAB) and polyethylene glycol (PEG400):HTAB as growth controlling agents. The surface tension of the spraying solutions was experimentally evaluated and was correlated with the deposition processes (nucleation and growth) of very smooth and homogenous films. The effect of the surfactant, alone and associated with PEG, on the structure (XRD), morphology (AFM), surface composition (XPS), FTIR and hydrophilicity (contact angle) were investigated and their influence on the electrochromic activity was discussed. Using surfactants and PEG, the coloration efficiency, transmission modulation and cycling stability of the WO3 thin films can be enhanced.
    Materials Chemistry and Physics. 06/2013; 140(1):49–59.
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    ABSTRACT: The present study provides a rapid way to obtain VO2 (B) under economical and environmentally friendly conditions. VO2 (B) is one of the well-known polymorphs of vanadium dioxide and is a promising cathode material for aqueous lithium ion batteries. VO2 (B) was successfully synthesized by rapid single-step hydrothermal process using V2O5 and citric acid as precursors. The present study shows that phase-pure VO2 (B) polytype can be easily obtained at 180 °C for 2 h and 220 °C for 1 h, that is, the lowest combination of temperature and duration reported so far. The obtained VO2 (B) is characterized by X-ray powder diffraction, high-resolution scanning electron microscopy, and Fourier transform infrared spectroscopy. In addition, we present an indirect way to obtain VO2 (M1) by annealing VO2 (B) under vacuum for 1 h.
    Inorganic Chemistry 04/2013; · 4.59 Impact Factor
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    ABSTRACT: Microenvironments such as protein composition, physical features, geometry and elasticity play important role in stem cell lineage specification. The components of the extracellular matrix (ECM) are known to subsequently assemble into fibrillar networks in vivo with defined periodicity. However, the effect of the most critical parameter which involves the periodicity of these fibrillar networks on the stem cell fate is not yet investigated. Here, we show the effect of synthetic fibrillar networks patterned with nanometric periodicities using bottom up approaches, on the response of stem cells. We have used helical organic nanoribbons based on self-assemblies of Gemini-type amphiphiles to access chiral silica nanoribbons with two different shapes and periodicities (twisted ribbons and helical ribbons) from the same native self-assembled organic nanostructure. We demonstrate the covalent grafting of these silica nanoribbons onto activated glass substrates and the influence of this programmed isotropically oriented matrix to direct the commitment of human mesenchymal stem cells (hMSCs) into osteoblast lineage in vitro, free of osteogenic inducing media. The specific periodicity of 63 nm (± 5 nm) with helical ribbon shape induces specific cell adhesion through the fibrillar Focal Adhesions (FAs) formation and leads to stem cell commitment into osteoblast lineage. In contrast, the matrix of periodicity 100 nm (± 15 nm) with twisted ribbon shape does not lead to osteoblast commitment. The inhibition of non-muscle myosin II with blebbistatin is sufficient to block this osteoblast commitment on helical nanoribbon matrix, demonstrating that stem cells interpret the nanohelical shape and periodicity environment physically. These results indicate that hMSCs could interpret nanohelical shape and periodicity in the same way they sense microenvironment elasticity. This provides a promising tool to promote hMSC osteogenic capacity, which can be exploited in 3D scaffold for bone tissue engineering.
    ACS Nano 03/2013; · 12.03 Impact Factor
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    ABSTRACT: Well-defined hybrid latex materials composed of a semi-conducting polymer (i.e. poly(3,4-ethylene dioxythiophene) (PEDOT)) and metal nano-objects (such as silver (Ag) or gold (Au)) were prepared by aqueous dispersion polymerization using ammonium persulfate as an oxidant and the corresponding metal salts as co-oxidants (HAuCl4 and AgNO3 respectively) in the presence of various reactive stabilizers such as aniline-modified-poly(vinyl alcohol) (PVAL-mod-An), pyrrole-modified-poly(vinyl alcohol) (PVAL-mod-Py), pyrrole-modified-poly(N-vinylpyrrolidone-co-vinyl alcohol) (PVP-co-PVAL-mod-Py), or α,ω-fluorene-poly(ethyleneoxide) (Flu-PEO-Flu). The effects of the nature and concentration of the reactive stabilizers as well as the addition time of the co-oxidant on the morphology of the hybrid nanoparticles thus formed are discussed. It is found that the addition time of the co-oxidant affects considerably the size and morphology of the PEDOT–metal nanocomposites.
    Polym. Chem. 01/2013; 4(3):615-622.
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    ABSTRACT: This manuscript describes the formation of spherical nanostructures on surfaces by interfacial migration of amphiphilic block copolymer micelles. The micelles are formed by macrophase separation of a polymer blend composed of polystyrene-b-poly(acrylic acid) (PS-b-PAA) block copolymers and a high molecular weight polystyrene matrix. The micelles formed in bulk are able to migrate towards the interface upon water vapor annealing, thus forming spherical nanodomains with the carboxylic groups of PAA exposed to the polymer/humid air interface. We explored herein the reversible modification of the PAA nanodomains by complexation with three different polymers, i.e. poly(N-vinylpyrrolidone) (PVP), poly(N-isopropylacrylamide) (PNiPAm) and poly(N-tert-butylacrylamide) (PNtBAm) via hydrogen bond interactions. Whereas the first two polymer complexes, are disrupted by changing the environmental pH in aqueous solution, the third polymer employed is able to form and disrupt the complexes by changing the solvent from either 1- or 2-propanol to methanol.
    European Polymer Journal 01/2013; 49(1):130–138. · 3.24 Impact Factor
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    ABSTRACT: Fluorination processes of polymer surfaces are able to lead to drastic modifications of the surface properties without changing the bulk characteristics of the virgin material. In this paper, two types of polymers, i.e. ultrahigh molecular weight polyethylene (UHMWPE) and high density polyethylene (HDPE), are considered. The surface of these materials have been modified using two different fluorination routes, both carried out at room temperature: the direct fluorination with 10% F2 + 90% He gaseous mixtures and the radio-frequency plasma-enhanced fluorination (PEF) using either O2/CF4 mixtures or c-C4F8. The effect of these processes on the surface of the polymer samples are compared using mostly XPS results. The different components of the C1s spectra are assigned in term of CFx bonding, giving valuable information on the surface fluorination rate.
    Acta Chimica Slovenica 01/2013; 60(3):495-504. · 1.14 Impact Factor
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    ABSTRACT: We report the selective functionalization of the external surface in honeycomb structured porous films while maintaining the functionality of the pores. For this purpose, we describe the preparation of polymer films from blends of polystyrene (PS) and polystyrene-b-poly(2,3,4,5,6-pentafluorostyrene) (PS-b-P5FS) by the breath figures approach. The diblock copolymer resulted to be homogeneously distributed along the whole surface of the films as a consequence of the reorientation towards the solution-air interface. The porous films obtained have a wetting behavior that can be described by the Cassie-Baxter state equations. This particular effect allowed us to modify the chemical composition of the film surface whilst the interior of the pores does not vary. As a proof of concept, we report the modification of the surface using "click" chemistry. Thiolated glucose molecules were attached specifically to the poly(2,3,4,5,6-pentafluorostyrene) domains via thiol-para fluorine "click" reaction. The kinetics of this reaction and the possibility to participate in recognition processes have been evaluated by contact angle measurements, X-ray photoelectron spectroscopy and fluorescence microscopy.
    Polymer Chemistry. 01/2013; 4(14):4024-4032.
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    ABSTRACT: The growth of Zn-based thin films, from pure ZnF2 to pure ZnO, has been investigated as a function of the oxygen partial pressure and substrate temperature using pulsed laser deposition. Starting from (1-x) ZnO-x center dot ZnF2 target compositions, ZOF films containing a low fluorine content (x < 0.10) have been successfully deposited. These films exhibit typical ZnO wurtzite structure while maintaining the (002) preferred orientation. The fluorine doping does not modify the film transparency (T approximate to 90%), whereas for a high fluorine content, a large haze effect is observed. Such effects are associated with increased surface roughness. The Hall effect measurements show a beneficial effect with the addition of F corresponding to a decrease in resistivity for ZOF thin films accounting for oxygen to fluorine substitution in the ZnO structure. In contrast, attempts at annealing in air of successfully deposited pure ZnF2 thin films does not lead to increased conductivity in the films: this is associated with a progressive transformation from ZnF2 to ZnO. Finally, improvements in the electrical properties are proposed for F and Si co-doping, and resistivities as low as 7.2 x 10(-4) Omega cm for SZOF thin films deposited at RT from a ZnO (87 at%)-ZnF2 (10 at%)-SiO2 (3 at%) target are achieved. (C) 2012 Elsevier B.V. All rights reserved.
    Solar Energy Materials and Solar Cells 12/2012; 107:136-141. · 5.03 Impact Factor
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    ABSTRACT: A new procedure focused on the design and preparation of structured and functional polymer surfaces by combination of two approaches acting simultaneously is developed. The elaboration of micrometer size patterned surfaces by UV-light lithography is reported where, in addition, the surface chemical composition can be controlled by surface segregation of a fluorinated copolymer incorporated in the photopolymerizable mixture. As evidenced by contact angle and XPS measurements, the surface composition can be modified depending on such factors as with the environmental conditions or the concentration of copolymer in the blend. Moreover, the functionality of the copolymer is enhanced by the surface pattern created. As a consequence, the wettability of the films can be modified depending on the pattern and composition of the blend. By using this methodology, functional adaptive sensitive surfaces with a well-defined topography will be obtained in one single step and without the use of tedious and time-consuming multistep procedures. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
    Journal of Polymer Science Part A Polymer Chemistry 12/2012; 50(23):4902-4910. · 3.54 Impact Factor
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    ABSTRACT: Silicon doped Zinc Oxide thin films, so-called SZO, were deposited at room temperature on glass and plastic substrates by co-sputtering of ZnO and SiO2 targets. The influence of the SiO2 target power supply (from 30 to 75 W) on the SZO thin film composition and crystallinity is discussed. Si/Zn atomic ratio, determined by X-ray microprobe, increases from 1.2 to 8.2 at.%. For Si/Zn ratio equal and lower than 3.9%, SZO (S(3.9)ZO) thin films exhibit the Wurzite structure with the (0 0 2) preferred orientation. Larger Si content leads to a decrease in crystallinity. With Si addition, the resistivity decreases down to 3.5x10(-3) Omega.cm for SZO thin film containing 3.9 at.% of Si prior to an increase. The mean transmittance of S(3.9)ZO thin film on glass substrate approaches 80% (it is about 90% for the film itself) in the visible range (from 400 to 750 nm). Co-sputtered SZO thin films are suitable candidates for large area transparent conductive oxides. (C) 2012 Elsevier B. V. All rights reserved.
    Thin Solid Films 12/2012; 524:151-156. · 1.87 Impact Factor
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    ABSTRACT: To control specific endothelial cell (EC) functions, cell adhesive RGDS, EC specific REDV and YIGSR peptides, and angiogenic SVVYGLR sequences were covalently immobilized onto polyethylene terephthalate (PET) surfaces for the purpose of cell culture. X-ray photoelectron spectroscopy, atomic force microscopy, fluorescence microscopy and contact angle measurement were employed for characterization of surface modifications. The peptide density on PET surfaces was evaluated by fluorescence microscopy. The surfaces immobilized with peptides were exposed to human umbilical vein endothelial cells to study their specific effects onto EC functions. The results showed that the surface functionalized by these peptides enhanced the EC adhesion, spreading and migration as compared with native PET surfaces. Specifically, the RGDS peptides induced more cell adhesion than other peptides. The YIGSR and SVVYGLR sequences induced more cell spreading and cell migration, represented by intense focal adhesion at the leading edges of cell spreading and migration. The bi-functionalization of RGDS and SVVYGLR peptides (MIX) combined the advantages of both peptides and induced significant EC adhesion, spreading and migration. Our study indicates that the surface functionalization by peptides specific for ECs, especially the combination of RGDS with SVVYGLR or YIGSR peptides, has potential applications in promoting endothelialization of vascular prostheses and for construction of vascularized tissues in tissue engineering.
    Journal of Materials Science Materials in Medicine 08/2012; · 2.14 Impact Factor
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    ABSTRACT: In this paper, a detailed study to examine the influence of chalcogen S/Se mole % in the Ge28Sb12S60 −xSex glass system, with x = 0, 15, 30, 45 and 60, is presented that provides insight into the effect of chalcogen content on the glass network and properties. Specifically, we report results of a systematic study to evaluate the relationship between compositional variation, glass properties and dominant bonding configurations. These materials are important to applications in optics manufacturing where correlation of physical and optical properties is required to predict fabrication behavior and ultimate material performance. It has been found that the dominant bonds in the glass system change upon reaching a specific molar ratio (percentage, %) of chalcogen substitution, between 30 < x < 45 mol%, changing from Ge―Se to Sb―Se bonds as the dominant bond type. This singularity has been observed using micro-Raman spectroscopy and X-ray photoelectron spectroscopy. This effect of the dominant bond configurational change was also shown to impart changes in important physical properties including micro-hardness, thermal properties, and the glass' viscometric behavior. Results indicate that the observed dominant bond change was responsible for a constant value in the evolution of both the micro-hardness and calorimetric glass transition temperature. The viscosity was also affected by the change in dominant bond type, breaking the monotony of the viscosity evolution during the S substitution, due to the total strength of the vitreous system which does not linearly increase.
    Journal of Non-Crystalline Solids 08/2012; 358(15):1740–1745. · 1.72 Impact Factor
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    ABSTRACT: Annealing in air of a precursor consisting of coprecipitated gadolinium and chromium hydroxides, containing, in equal proportion, 119Sn4+ Mössbauer dopant cations and Ca2+ co-dopant cations, leads to the location of Sn4+ ions, in the bulk of the formed GdCrO3 crystallites, on the Cr3+ site with the unaltered magnetically active surrounding. These Sn4+ ions are characterized by hyperfine field H78 K equal to 64 kOe. This value, intermediate between those observed in LaCrO3 and LuCrO3, shows that the spin polarization of Sn4+ originates mainly from a π-type overlap of Cr3+t2g3 -orbitals with O2− 2p-orbitals. In the absence of Ca2+ co-dopant cations, the compensation of the excess charge of Sn4+ in the structure of GdCrO3 involves the formation of Cr3+ vacancies and, to a lesser extent, of Gd3+ vacancies. The vacancies of both types appear to be located in the vicinity of one-third of the Sn4+ dopant ions. In hydrogen atmosphere, annealing the precursor, containing only Sn4+ dopant ions, leads to reduction of Sn4+ ions to the divalent state with concomitant location of the dopant on surface sites of crystallites. Upon contact with ambient air, these Sn2+ ions are rapidly oxidized. Approximatively one-third of the formed Sn4+ exhibit no spin polarization (H78 K = 0 kOe) while two-thirds of them reveal considerable weakening in spin polarization as compared to that in the bulk of crystallites. The non-polarized Sn4+ ions are assigned to Gd surface sites and the weakly polarized Sn4+ ions to Cr surface sites with a reduced number of magnetically active Cr3+ neighboring cations.
    Comptes Rendus Chimie. 07/2012; 15(7):609–616.
  • Fluorine Notes Journal. 01/2012; 3(82).
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    ABSTRACT: Hybrid org.-inorg. nanocomposites of poly(3,4-ethylenedioxythiophene) (PEDOT) and silver or gold {PEDOT-metal (PEDOT-M) nano-objects (M = Ag, Au) (particle diam. down to 60 nm)} were prepd. by a one-pot oxidative aq. dispersion polymn. using ammonium persulfate as an oxidant and the corresponding metal salts as co-oxidant (HAuCl4 and AgNO3) in the presence of pyrrole-modified-poly(N-vinylpyrrolidone-co-vinyl alc.) (PVP-co-PVAL-mod-Py) stabilizer. The hydrophilic character of such a stabilizer enhances the polymer layer through hydrophilic interactions, which leads to a smooth surface with high wetting properties for subsequent electropolymns. PEDOT-M is more conducting than the com. available PEDOT:PSS, in which the PSS acts as an insulating agent (elec. conductivities up to 1.25 S cm-1). These nanocomposites were used to replace PEDOT:PSS as anchoring layer for further EDOT monomer polymn., providing an improvement of the electrochromic properties of PEDOT in terms of not only contrast ratio and coloration efficiency but also switching time response. [on SciFinder(R)]
    Berichte der deutschen chemischen Gesellschaft 01/2012; 2012(Copyright (C) 2012 American Chemical Society (ACS). All Rights Reserved.):5360-5370. · 2.94 Impact Factor
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    ABSTRACT: Calcination of cyclopentadienyltitanium-based organic-inorganic hybrid materials at 450-500 °C led to the formation of anatase titanium dioxide as white powders consisting of a porous network of aggregated nanoparticles, the nanoporosity detected being related to the inter-particle space. Depending on the calcination temperatures, the surface area of the titanium dioxide particles varied from 65 to 158 m(2) g(-1).
    Dalton Transactions 11/2011; 41(1):292-9. · 3.81 Impact Factor

Publication Stats

564 Citations
230.81 Total Impact Points

Institutions

  • 2007–2014
    • University of Bordeaux
      Burdeos, Aquitaine, France
    • French Institute of Health and Medical Research
      Lutetia Parisorum, Île-de-France, France
  • 2001–2014
    • Université Bordeaux 1
      • • UMR ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
      • • UMR LCPO - Laboratoire de Chimie des Polymères Organiques
      Talence, Aquitaine, France
  • 2013
    • University of Nantes
      Naoned, Pays de la Loire, France
  • 2001–2013
    • Institut de Chimie de la matière condensée de Bordeaux
      Pessac, Aquitaine, France
  • 2012
    • Université Victor Segalen Bordeaux 2
      Burdeos, Aquitaine, France
  • 1996–2012
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France