Author: "Cristelle Mériadec" - Searchworks@Jio Institute Digital Library Search Results

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56 results on '"Cristelle Mériadec"'

1. Polyoxothiometalate-Derivatized Silicon Photocathodes for Sunlight-Driven Hydrogen Evolution Reaction

Author: Dong Fu, Bruno Fabre, Gabriel Loget, Cristelle Mériadec, Soraya Ababou-Girard, Emmanuel Cadot, Nathalie Leclerc-Laronze, Jérôme Marrot, and Quentin de Ponfilly
Subjects: Chemistry, QD1-999
Published: 2018
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2. Milk sphingosomes as lipid carriers for tocopherols in aqueous foods: Thermotropic phase behaviour and morphology

Author: Christelle Lopez, Elisabeth David-Briand, Cristelle Mériadec, Claudie Bourgaux, Javier Pérez, Franck Artzner, Unité de recherche sur les Biopolymères, Interactions Assemblages (BIA), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Institut Galien Paris-Saclay (IGPS), Institut de Chimie du CNRS (INC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), and Synchrotron Soleil
Subjects: [PHYS]Physics [physics], alpha-Tocopherol, Vesicle, Tocopherols, Water, Milk polar lipid, Lipids, Liposome, Lipophilic antioxidant, Milk, Lipid membrane, [SDV.IDA]Life Sciences [q-bio]/Food engineering, Animals, Encapsulation, Milk sphingomyelin, Food Science, Phase transition
Abstract: International audience; Foods containing polyunsaturated lipids are prone to oxidation. Designing food-grade hydrocolloidal encapsulation systems able to load lipophilic antioxidant molecules, such as tocopherols (vitamin E), is necessary to prevent oxidation and its deleterous consequences. In this study, we hypothesised that α-tocopherol molecules could incorporate in a host membrane composed of milk sphingomyelin (milk-SM) and performed a multi-scale biophysical study. The thermal properties of milk-SM bilayers with various molar proportions of α-tocopherol were characterised by differential scanning calorimetry (DSC), their structural properties were examined by X-ray diffraction (XRD). The miscibility between milk-SM and α-tocopherol was investigated in mixed Langmuir monolayers. The morphology of milk-SM sphingosomes was observed by confocal laser scanning microscopy (CLSM). We found that molecules of α-tocopherol inserted into the milk-SM bilayers and induced a physical desorganisation in the membrane packing, both in the ordered and fluid states. In the presence of α-tocopherol, the bilayers were no longer in a gel phase below the phase transition temperature Tm, but in the liquid ordered Lo phase. Furthermore, the sphingosomes formed elongated structures in presence of α-tocopherol as a result of membrane softening and changes in the bilayer curvature associated to membrane fusion. The findings of this work contribute in a better understanding of the capacity of milk-SM bilayers to incorporate guest molecules. Milk-SM sphingosomes loaded with tocopherols could be used to prevent oxidation in aqueous foods containing polyunsaturated lipids such as oil-in-water emulsions. © 2022 Elsevier Ltd
Published: 2022

3. Bismuth‐Decorated Silicon Photocathodes for CO 2 ‐to‐Formate Solar‐Driven Conversion

Author: Dong Fu, Bruno Fabre, Soraya Ababou-Girard, Cristelle Mériadec, Gabriel Loget, Yaoyin Lou, Florence Geneste, Jeoffrey Tourneur, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), ANR (Agence Nationale de la Recherche) French National Research Agency (ANR) [CHALCO-CAT ANR-15-CE06-0002-01], University of Rennes 1, CNRS Centre National de la Recherche Scientifique (CNRS), ANR-15-CE06-0002,Chalco-Cat,Electrocatalyseurs à base d'oxysulfures moléculaires pour la conversion de l'énergie(2015), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Silicon, Inorganic chemistry, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Catalysis, Bismuth, Inorganic Chemistry, chemistry.chemical_compound, formate, photocathodes, Formate, Physical and Theoretical Chemistry, [PHYS]Physics [physics], Organic Chemistry, silicon, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, 0104 chemical sciences, CO(2)electrocatalytic reduction, chemistry, bismuth catalysts, 0210 nano-technology
Abstract: International audience; The integration of metal-based catalysts onto semiconducting electrodes provides a real benefit for the CO(2)electrochemical conversion because it allows the electrochemical process to be activated by photogenerated electrons. In that context, we report here that silicon photocathodes modified with electrodeposited Bi nanostructures are highly active for the photoelectrocatalytic conversion of CO(2)to formate. Through the consumed electrical charge and the electrodeposition time, it is possible to finely control both the structure and the density of the deposited catalyst. The optimal photocathode was prepared by using a 5 s electrodeposition time and exhibited the highest photocurrent density (-24.1 mA cm(-2)) with partial formate photocurrent densityj(formate)=-17.4 mA cm(-2)at -1.03 V vs Reversible Hydrogen Electrode (RHE), i. e. a 0.84 V overpotential for CO(2)to formate conversion in CO2-saturated 0.5 M KHCO(3)solution. Such values highlight the excellent photoelectrocatalytic activity of our photocathodes.
Published: 2020

4. Membrane mimetic bolaamphiphiles and the role of the nature of lipid chains

Author: Jelena Jeftic, Matthieu Berchel, Cristelle Mériadec, Loic Lemiegre, Franck ARTZNER, Thierry Benvegnu, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Brest (UBO), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Jonchère, Laurent, Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract: International audience
Published: 2021

5. Molecular Engineering onto Ru

Author: Olivier, Galangau, Dania, Daou, Nour, El Beyrouti, Elsa, Caytan, Cristelle, Mériadec, Franck, Artzner, and Stéphane, Rigaut
Abstract: In this article, we report the successful molecular engineering of Ru bis-acetylides that led for the first time to a gelator and more specifically in aromatic solvents. By means of a nonlinear ligand and an extended aromatic platform, the bulky Ru bis-acetylides were able to self-assemble into lamellar structures as evidenced by scanning electron microscopy (SEM) in benzene, toluene, and
Published: 2021

6. Molecular and Material Engineering of Photocathodes Derivatized with Polyoxometalate-Supported {Mo3S4} HER Catalysts

Author: Bruno Fabre, Nathalie Leclerc-Laronze, Antoine Vacher, Cristelle Mériadec, Clément Falaise, Soraya Ababou-Girard, Francis Gouttefangeas, Jeoffrey Tourneur, Loïc Joanny, Emmanuel Cadot, Mohamed Haouas, Gabriel Loget, Emmanuel Guillon, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Synthèse Caractérisation Analyse de la Matière (ScanMAT), Université de Rennes (UR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre de Microscopie Electronique à Balayage et microAnalyse (C.M.E.B.A.), Université de Rennes (UR), Institut Lavoisier de Versailles (ILV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Moléculaire de Reims - UMR 7312 (ICMR), Université de Reims Champagne-Ardenne (URCA)-Institut de Chimie du CNRS (INC)-SFR CAP Santé (Champagne-Ardenne Picardie Santé), Université de Reims Champagne-Ardenne (URCA)-Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS)-SFR Condorcet, Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), ANR (Agence Nationale de la Recherche) [ANR-15-CE06-0002-01], University of Rennes 1, University of Versailles Saint Quentin, LabEx CHARMMMAT of University Paris-Saclay [ANR-11-LABX-0039], CNRS, ANR-11-IDEX-0003,IPS,Idex Paris-Saclay(2011), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut de Chimie du CNRS (INC), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), SFR Condorcet, Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-SFR CAP Santé (Champagne-Ardenne Picardie Santé), and Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], Thesaurus (information retrieval), Chemistry, Nanotechnology, General Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, 0104 chemical sciences, Molecular engineering, Search engine, Colloid and Surface Chemistry, Polyoxometalate, [CHIM]Chemical Sciences
Abstract: International audience; Molecular engineering of efficient HER catalysts is an attractive approach for controlling the spatial environment of specific building units selected for their intrinsic functionality required within the multistep HER process. As the {Mo 3 S 4 } core derived as various coordination complexes has been identified as one as the most promising MoS x-based HER electrocatalysts, we demonstrate that the covalent association between the {Mo 3 S 4 } core and the redox-active macrocyclic {P 8 W 48 } polyoxometalate (POM) produces a striking synergistic effect featured by high HER performance. Various experiments carried out in homogeneous conditions showed that this synergistic effect arises from the direct connection between the {Mo 3 S 4 } cluster and the toroidal {P 8 W 48 } units featured by a stoichiometry which can be tuned from two to four {Mo 4 S 4 } cores per {P 8 W 48 } unit. In addition, we report that this effect is preserved within heterogeneous photoelectrochemical devices where the {Mo 3 S 4 }-{P 8 W 48 } (thio-POM) assembly was used as co-catalyst (cocat) onto a microstructured p-type silicon. Using drop-casting procedure to immobilize cocat onto the silicon interface led to high initial HER performance under simulated sunlight achieving a photocurrent density of 10 mA.cm-2 at +0.13 V vs RHE. Furthermore, electrostatic incorporation of the thio-POM anion cocat into a poly(3,4-ethylenedioxythiophene) (PEDOT) film is demonstrated to be efficient and straightforward to durably retain the cocat at the interface of a micropyramidal silicon (SimPy) photocathode. The thio-POM/PEDOT-modified photocathode is able to produce H 2 under 1 Sun illumination at a rate of ca. 100 µmol cm-2 h-1 at 0 V vs RHE, highlighting the excellent performance of this photoelectrochemical system.
Published: 2019

7. Boosting the Performance of BiVO4Prepared through Alkaline Electrodeposition with an Amorphous Fe Co‐Catalyst

Author: Didier Floner, Stéphanie Fryars, Gabriel Loget, Cristelle Mériadec, Rawa Abdallah, Soraya Ababou-Girard, Hiba Saada, Vincent Dorcet, Antoine Vacher, Bruno Fabre, Lebanese University [Beirut] (LU), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), CNRS, Université de Rennes 1, Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], Photocurrent, Materials science, business.industry, 02 engineering and technology, Photoelectrochemical cell, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 7. Clean energy, Isotropic etching, Catalysis, 0104 chemical sciences, Amorphous solid, chemistry.chemical_compound, Semiconductor, chemistry, Chemical engineering, Bismuth vanadate, Electrochemistry, [CHIM]Chemical Sciences, Water splitting, 0210 nano-technology, business
Abstract: International audience; BiVO4 is a promising n‐type semiconductor for water‐splitting photoelectrochemical cells. We report here a new method to prepare BiVO4 photoanodes that is based on an alkaline electrodeposition process, which avoids chemical etching of Bi. In addition, we present a simple and general method to prepare coatings of amorphous FeOx that behave as a co‐catalyst on our BiVO4 material, improving the water splitting photocurrent.
Published: 2018

8. Polyoxothiometalate-Derivatized Silicon Photocathodes for Sunlight-Driven Hydrogen Evolution Reaction

Author: Jérôme Marrot, Quentin de Ponfilly, Gabriel Loget, Emmanuel Cadot, Nathalie Leclerc-Laronze, Bruno Fabre, Cristelle Mériadec, Soraya Ababou-Girard, Dong Fu, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Institut Lavoisier de Versailles (ILV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), ANR (Agence Nationale de la Recherche) [ANR-15-CE06-0002-01], University of Rennes 1, University of Versailles Saint Quentin, LabEx CHARMMMAT of University Paris-Saclay [ANR-11-LABX-0039], CNRS, ANR-15-CE06-0002,Chalco-Cat,Electrocatalyseurs à base d'oxysulfures moléculaires pour la conversion de l'énergie(2015), ANR-11-IDEX-0003,IPS,Idex Paris-Saclay(2011), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], Valence (chemistry), Materials science, Silicon, Ligand, General Chemical Engineering, chemistry.chemical_element, 02 engineering and technology, General Chemistry, Electrolyte, 010402 general chemistry, 021001 nanoscience & nanotechnology, Photochemistry, 01 natural sciences, Article, Photocathode, 0104 chemical sciences, Catalysis, lcsh:Chemistry, lcsh:QD1-999, chemistry, X-ray photoelectron spectroscopy, Polyoxometalate, 0210 nano-technology
Abstract: International audience; Silicon photocathodes coated with drop-casted {Mo3S4}-based polyoxothiometalate assemblies are demonstrated to be effective for sunlight-driven hydrogen evolution reaction (HER) in acid conditions. These photocathodes are catalytically more efficient than that coated with the parent thiomolybdate incorporating an organic ligand, as supported by a higher onset potential and a lower overvoltage at 10 mA cm(-2). At pH 7.3, the trend is inversed and the beneficial effect of the polyoxometalate for the HER is not observed. Moreover, the polyoxothiometalate-modified photocathode is found to be also more stable under acid conditions and can be operated at the light-limited catalytic current for more than 40 h. Furthermore, X-ray photoelectron spectroscopy and atomic force microscopy measurements indicate that the cathodic polarization of both photocathodes leads to the release of a large amount of the deposited material into the electrolyte solution concomitantly with the formation of mixed valence species {Mo(IV)(3-x)Mo(III)(x)O4-nSn}((4-x)+) resulting from the replacement of S2- sulfido ligands in the cluster by oxo O2- groups; these combined effects are shown to be beneficial for the photoelectrocatalysis.
Published: 2018

9. Controlling the Emission Properties of Quantum Rods via Multiscale 3D Ordered Organization

Author: Charlie Gosse, Mircea Cotlet, Christophe Dupuis, Valérie Marchi, Florian Meneau, Oleg Gang, Pascal Panizza, Elsa Mazari-Arrighi, Pascale Even-Hernandez, Thomas Bizien, Cristelle Mériadec, Marie Postic, Franck Artzner, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Laboratório Nacional de Luz Sìncrotron (LNLS), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Laboratoire de photonique et de nanostructures (LPN), Brookhaven National Laboratory [Upton, NY] (BNL), U.S. Department of Energy [Washington] (DOE)-UT-Battelle, LLC-Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY), Columbia University [New York], The Agence Nationale de la Recherche (ANR contract No. 16-CE09-0027-02 HYPNAP and contract No. 14-CE08-0004 ARTEMIS) funded this work. We are indebted to the Region Bretagne, the French Direction Generale de l’Armement, and the ANR for the PhD financial supports to T. Bizien, M. Postic, and E. Mazari-Arrighi. We also acknowledge Université de Rennes for a travel grant to T. Bizien, so as to enable him to perform measurements at the Center for Functional Nanomaterials of the Brookhaven National Laboratory and Rennes Métropoles for equipment support. Oleg Gang was supported by the US Department of Defense, Army Research Office, grant W911NF-19-1-0395. This research used resources of the Center for Functional Nanomaterials, supported by U.S. DOE Office of Science Facilities at Brookhaven National Laboratory under contract No. DE-SC0012704., ANR-16-CE09-0027,HYBNAP,UNE PLATEFORME NANOPLASMONIQUE HYBRIDE EMETTEUR-COLLOÏDE METALLIQUE(2016), ANR-14-CE08-0004,ARTEMIS,Auto-assemblage et Intégration de Métamatériaux par Ingénierie de Protéines Artificielles(2014), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centro Nacional de Pesquisa em Energia e Materiais = Brazilian Center for Research in Energy and Materials (CNPEM), UT-Battelle, LLC-Stony Brook University [SUNY] (SBU), State University of New York (SUNY)-State University of New York (SUNY)-U.S. Department of Energy [Washington] (DOE), and ANR-14-CE19-0004,CROC,Contrôle de la fréquence de recombinaison méiotique pour accélérer l'innovation variétales chez les espèces cultivées polyploïdes(2014)
Subjects: Materials science, genetic structures, Article Subject, 02 engineering and technology, Electron, 010402 general chemistry, 01 natural sciences, T1-995, [CHIM]Chemical Sciences, General Materials Science, Nanoscopic scale, Technology (General), [PHYS]Physics [physics], Scattering, business.industry, 021001 nanoscience & nanotechnology, Emission intensity, Aspect ratio (image), Fluorescence, eye diseases, 0104 chemical sciences, Optoelectronics, sense organs, 0210 nano-technology, Luminescence, Columnar phase, business
Abstract: International audience; A specific organization of optically active nanoscale objects can greatly affect the optical response of a system. Here, we report the controlled modification of the fluorescent emission by the assembly of water-soluble quantum rods (QRs). Our study combines optical, electron microcopy, and X-ray scattering characterizations to reveal a correlation between the self-assembly behavior of QRs into ordered 3D-arrays and the optical properties (luminescence) of formed assemblies, where the observed optical response is highly dependent on the QR aspect ratio. Specifically, shorter, 18 nm long QRs (QR18), exhibiting a well-defined smectic packing, demonstrate an enhancement of the emission intensity accompanied by a red shift and a lifetime reduction. In contrast, 40 nm long QRs (QR40), forming a columnar phase, does not show these optical properties.
Published: 2021
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10. Structure–Property Relationships in Redox-Derivatized Metal–Insulator–Semiconductor (MIS) Photoanodes

Author: Pichaya Pattanasattayavong, Gabriel Loget, Cristelle Mériadec, Soraya Ababou-Girard, Vincent Dorcet, Stéphanie Fryars, Ponart Aroonratsameruang, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Vidyasirimedhi Institute of Science and Technology [Thaïlande] (VISTEC), Synthèse Caractérisation Analyse de la Matière (ScanMAT), Université de Rennes (UR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Vidyasirimedhi Institute of Science and Technology, Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut de Chimie du CNRS (INC), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: metal-insulator-semiconductor (MIS), energy conversion, Materials science, Nanotechnology, 02 engineering and technology, 010402 general chemistry, Electrocatalyst, 7. Clean energy, 01 natural sciences, Redox, Physical and Theoretical Chemistry, Metal insulator, Prussian blue analogs, business.industry, Structure property, silicon, 021001 nanoscience & nanotechnology, Durability, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, General Energy, Semiconductor, oxygen evolution reaction, Electrode, 0210 nano-technology, business, [CHIM.OTHE]Chemical Sciences/Other
Abstract: International audience; Metal–insulator–semiconductor (MIS) junctions based on n-Si have proven to be effective electrodes in terms of electrocatalysis activity and durability for performing photoelectrochemical water oxidation. Here, we show that the modification of n-Si MIS systems with CoFe Prussian blue (CoFePB) and NiRu Prussian blue (NiRuPB) analogues can modify their properties and allow a direct probing of the interfacial energetics through their redox feature. Our investigations demonstrate the importance of the preparation route and attribute the large upward photovoltage variation found in n-Si/SiOx/Ni/NiRuPB to the increasing inhomogeneity of the metal thin film. Finally, the optimal photoanode was tested for oxygen evolution and urea oxidation reactions. Our findings provide important insights on MIS photoanodes for future development in the field of solar fuel production.
Published: 2020

11. Loading of lutein in egg-sphingomyelin vesicles as lipid carriers: Thermotropic phase behaviour, structure of sphingosome membranes and lutein crystals

Author: Marc Anton, Aurélien Dupont, Elisabeth David-Briand, Cristelle Mériadec, Christelle Lopez, Franck Artzner, Thomas Bizien, Alain Riaublanc, Science et Technologie du Lait et de l'Oeuf (STLO), AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Unité de recherche sur les Biopolymères, Interactions Assemblages (BIA), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Biosit : biologie, santé, innovation technologique (SFR UMS CNRS 3480 - INSERM 018), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique ), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-INSTITUT AGRO Agrocampus Ouest, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique ), and Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-AGROCAMPUS OUEST
Subjects: Lutein, endocrine system, Membrane bilayer, 030309 nutrition & dietetics, Lipid Bilayers, Sphingolipid, 03 medical and health sciences, chemistry.chemical_compound, 0404 agricultural biotechnology, Differential scanning calorimetry, X-Ray Diffraction, Humans, Carotenoid, chemistry.chemical_classification, [PHYS]Physics [physics], 0303 health sciences, Liposome, Chromatography, Calorimetry, Differential Scanning, Vesicle, Functional food, Aqueous two-phase system, food and beverages, 04 agricultural and veterinary sciences, 040401 food science, eye diseases, Sphingomyelins, chemistry, Xanthophyll, Encapsulation, sense organs, Sphingomyelin, [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition, Food Science
Abstract: International audience; Lutein is a xanthophyll carotenoid provided exclusively by the diet, that has protective functions and beneficial effects on human health. Supplementation in lutein is necessary to reach the recommended daily dietary intake. However, the introduction of lutein into foods and beverages is a real challenge since this lipophilic nutrient has a poor aqueous solubility and a low bioavailability. In this study, we investigated the capacity of egg-sphingomyelin (ESM) vesicles called sphingosomes to solubilise lutein into the bilayers. The thermal and structural properties of ESM bilayers were examined in presence of various amounts of lutein by differential scanning calorimetry (DSC) and temperature-controlled X-ray diffraction (XRD), the structures of sphingosomes and lutein crystals were observed by microscopic techniques. ESM bilayers were in the fluid L α phase above the phase transition temperature T m = 39.6 • C and in the lamellar ripple P β ′ phase below T m where ESM sphingo-somes exhibited ondulations and were facetted. Lutein molecules were successfully incorporated into the ESM bilayers where they induced a structural disorganisation. For ESM/lutein 90/10 %mol (91.8/8.2 %wt; 89 mg lutein / g ESM), lutein partitioning occured with the formation of lutein crystals in the aqueous phase together with lutein-loaded ESM vesicles. This study highlighted the capacity of new lipid carriers such as egg-sphingosomes to solubilise lutein and opens perspectives for the formulation of effective lutein-fortified func-tionnal foods and beverages providing health benefits.
Published: 2020

12. Hybrid gold nanoparticle-quantum dot self-assembled nanostructures driven by complementary artificial proteins

Author: Agathe Urvoas, Erik Dujardin, M. Fernandez, Agnès Burel, Franck Artzner, Cristelle Mériadec, Tahar Bouceba, Valérie Marchi, Philippe Minard, Pascale Even-Hernandez, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre de Microscopie de Rennes (MRic), Université de Rennes (UR)-Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique ), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Institut de Biologie Paris Seine (IBPS), Institut National de la Santé et de la Recherche Médicale (INSERM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre d'élaboration de matériaux et d'études structurales (CEMES), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), ANR-14-CE08-0004 ARTEMIS, Agence Nationale de la Recherche, Région Bretagne, ANR-14-CE08-0004,ARTEMIS,Auto-assemblage et Intégration de Métamatériaux par Ingénierie de Protéines Artificielles(2014), Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Rennes-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Structure Fédérative de Recherche en Biologie et Santé de Rennes ( Biosit : Biologie - Santé - Innovation Technologique ), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)
Subjects: Electrophoresis, Nanostructure, Materials science, Scattering, Metal Nanoparticles, Proteins, Nanoparticle, Physics::Optics, Nanotechnology, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, Surface Plasmon Resonance, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Quantum dot, Colloidal gold, Quantum Dots, General Materials Science, Gold, Surface plasmon resonance, 0210 nano-technology, Plasmon
Abstract: International audience; Hybrid nanostructures are constructed by the direct coupling of fluorescent quantum dots and plasmonic gold nanoparticles.The self-assembly is directed by the strong affinity between two artificial α-Repeat proteins that are introduced in thecapping layers of the nanoparticles at a controlled surface density. The proteins have been engineered to exhibit a highmutual affinity, corresponding to a dissociation constant in the nanomolar range, which is conferred to the proteinfunctionalizedquantum dots and gold nanoparticles. Protein-mediated self-assembly is evidenced by Surface PlasmonResonance and gel electrophoresis. The size and the structure of colloidal superstructures of complementary nanoparticlesis analyzed by transmission electronic microscopy and small angle X-ray scattering. The size of the superstructures isdetermined by the number of proteins per nanoparticle. The well-defined geometry of the rigid protein complex sets a highlyuniform interparticle distance of 8 nm that affects the emission properties of the quantum dots in the hybrid ensembles.Our results open the route to the design of hybrid emitter-plasmon colloidal assemblies with controlled near-field couplingand better optical response.
Published: 2020

13. Comparison between a wax/volatile oil mixture and vegetable butters in a long-lasting make-up formula: A rheological and structural study compared to product performance

Author: Cristelle Mériadec, Pascal Panizza, Franck Artzner, Hélène de Clermont-Gallerande, Charlène Hubert, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Chanel Parfums Beauté, and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Long lasting, Oils, fats, and waxes, 030309 nutrition & dietetics, media_common.quotation_subject, formulation, Raw material, 010402 general chemistry, 01 natural sciences, Biochemistry, Cosmetics, long-lasting eyeshadow, 03 medical and health sciences, chemistry.chemical_compound, Rheology, TP670-699, Mathematics, media_common, [PHYS]Physics [physics], 0303 health sciences, Wax, Consumer demand, jojoba butters, Pulp and paper industry, 0104 chemical sciences, chemistry, visual_art, Product (mathematics), visual_art.visual_art_medium, Petroleum, Agronomy and Crop Science, volatile oil, Food Science
Abstract: International audience; The long-lasting make-up was created to avoid migration of the product on the skin throughout the day. Currently, the formulation technology most commonly used to obtain it is based on the use of film-forming agents with volatile oils. However, with the growing trend in natural cosmetics, petroleum-based volatile compounds are increasingly being abandoned. The objective of this study is to determine whether a mixture of plant-based butters can be chosen to replace a mixture of volatile oil and synthetic wax in a long-lasting eyeshadow. Initial comparisons were made between two jojoba butters and a wax/volatile oil mixture in order to identify the best candidate to replace the latter. Then, the best candidate was incorporated into formula and finished formulas were compared using sensory evaluation, rheology and X-ray scattering. The results show that it is possible to preserve texture, rheological properties and structural organization of a formula by replacing a wax/oil mixture with vegetable butters. However, this does not mean that the formulas will behave the same on the eyelids over time. This work illustrates the real complexity faced by formulators when they must replace one raw material with another while guaranteeing the durability of all the product's properties. This challenge is more relevant today as consumer demand for products based on natural ingredients is growing.
Published: 2020

14. Direct SN1 reaction at oxidized PPF surfaces

Author: Frédéric Barrière, Corinne Lagrost, Hassiba Smida, M. Cortés, Cristelle Mériadec, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
Subjects: Chemistry, Nanotechnology, 02 engineering and technology, Photoresist, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrochemistry, 01 natural sciences, 0104 chemical sciences, lcsh:Chemistry, SN1 reaction, lcsh:Industrial electrochemistry, lcsh:QD1-999, X-ray photoelectron spectroscopy, Covalent bond, Monolayer, Polymer chemistry, [CHIM]Chemical Sciences, Surface modification, 0210 nano-technology, Pyrolysis, lcsh:TP250-261
Abstract: For comparative purposes, two series of pyrolyzed photoresist film (PPF) substrates are prepared with and without reductive conditions, i.e. in the presence and absence of H2. Electrochemical and X-ray photoelectron spectroscopy analyses show that PPF substrates prepared in the absence of H2 possess many more surface oxygen functional groups, mostly hydroxyl groups, than PPF prepared under reductive conditions. These oxidized PPF samples can be advantageously involved in an SN1 reaction to covalently bind ferrocenyl groups to the surface as (sub-)monolayers. Keywords: Surface functionalization, PPF, SN1 reaction, Monolayer
Published: 2017

15. Spontaneous decoration of silicon surfaces with MoOxnanoparticles for the sunlight-assisted hydrogen evolution reaction

Author: Jean-François Bergamini, Cristelle Mériadec, Gabriel Loget, T.-G. Truong, O. De Sagazan, Soraya Ababou-Girard, Bruno Fabre, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Institut d'Électronique et des Technologies du numéRique (IETR), Université de Nantes (UN)-Université de Rennes 1 (UR1), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Aqueous solution, Fabrication, Chemical substance, Silicon, chemistry.chemical_element, Nanoparticle, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, law.invention, Anti-reflective coating, chemistry, law, [CHIM]Chemical Sciences, General Materials Science, 0210 nano-technology, Science, technology and society, Faraday efficiency
Abstract: International audience; The immersion of oxide-free Si surfaces in MoS42- aqueous solutions induces their spontaneous decoration with isolated MoOx nanoparticles (NPs). The process is versatile and was used on planar Si (100) as well as on antireflective Si (111) micro-pyramid (SimPy) arrays. The NP decoration does not affect the optical properties of the surface in the visible range and improves the performances of hydrogen evolution reaction (HER) under simulated sunlight. The simplicity and the scalability of the technique make it highly promising for the fabrication of catalytically active photoelectrodes. More specifically, the MoOx-decorated SimPy produced H2 at a rate of 11 μmol cm-2 min-1 with a faradaic efficiency higher than 90 % at -0.35 V vs RHE. Furthermore, this process can be of strong interest for other applications in high-performance electronic devices.
Published: 2017

16. Tailoring the photoelectrochemistry of catalytic metal-insulator-semiconductor (MIS) photoanodes by a dissolution method

Author: Soraya Ababou-Girard, Gabriel Loget, Vincent Dorcet, Cristelle Mériadec, Antoine Vacher, Stéphanie Fryars, Bruno Fabre, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes-Centre National de la Recherche Scientifique (CNRS), Synthèse Caractérisation Analyse de la Matière (ScanMAT), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), ANR [ANR-16-CE09-0001-01], ANR-16-CE09-0001,EASi-NANO,Nanostructuration Electrochimique du Silicium pour la Fabrication de Surfaces Fonctionnelles à un Coût Réduit(2016), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0301 basic medicine, Materials science, Science, Photoelectrochemistry, General Physics and Astronomy, Nanotechnology, 02 engineering and technology, Electrocatalyst, 7. Clean energy, Article, General Biochemistry, Genetics and Molecular Biology, Solar fuels, 03 medical and health sciences, Microelectronics, Photocatalysis, Thin film, lcsh:Science, Dissolution, ComputingMilieux_MISCELLANEOUS, [PHYS]Physics [physics], Multidisciplinary, business.industry, [CHIM.CATA]Chemical Sciences/Catalysis, General Chemistry, Photoelectrochemical cell, 021001 nanoscience & nanotechnology, Surface chemistry, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, 030104 developmental biology, Semiconductor, lcsh:Q, Electrocatalysis, [CHIM.OTHE]Chemical Sciences/Other, 0210 nano-technology, business
Abstract: Apart from being key structures of modern microelectronics, metal-insulator-semiconductor (MIS) junctions are highly promising electrodes for artificial leaves, i.e. photoelectrochemical cells that can convert sunlight into energy-rich fuels. Here, we demonstrate that homogeneous Si/SiOx/Ni MIS junctions, employed as photoanodes, can be functionalized with a redox-active species and simultaneously converted into high-photovoltage inhomogeneous MIS junctions by electrochemical dissolution. We also report on the considerable enhancement of performance towards urea oxidation, induced by this process. Finally, we demonstrate that both phenomena can be employed synergistically to design highly-efficient Si-based photoanodes. These findings open doors for the manufacturing of artificial leaves that can generate H2 under solar illumination using contaminated water., Designing synthetic systems to convert light into fuel is crucial in renewable energy development. Here, authors study electrodissolution in nickel thin films from metal-insulator-semiconductor junctions and find decreased homogeneity to improve junction properties and catalytic performances.
Published: 2019

17. Organic Nanoscrolls from Electrostatic Interactions between Peptides and Lipids: Assembly Steps and Structure

Author: Christophe Chassaing, Cristina Petcut, Joël Richard, Naziha Benamar, Keinny François, Damien Rault, Franck Artzner, Maité Paternostre, Cristelle Mériadec, Thomas Bizien, Pierre Chervy, Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Interactions et mécanismes d’assemblage des protéines et des peptides (IMAPP), Département Biochimie, Biophysique et Biologie Structurale (B3S), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Biologie Intégrative de la Cellule (I2BC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Ipsen [Boulogne Billancourt] (Ipsen), IPSEN, ANR and Ipsen, ANR-14-LAB5-0001,ArchiPex,Auto-Assemblage et formulations de peptides thérapeutiques(2014), ANR-10-INBS-0005,FRISBI,Infrastructure Française pour la Biologie Structurale Intégrée(2010), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), and Institute for Integrative Biology of the Cell (I2BC)
Subjects: Self-assembly mechanism, MESH: peptide, MESH: electrostatic interactions, MESH: supramolecular architectures, Lipid Bilayers, Static Electricity, Peptide, 02 engineering and technology, Supramolecular architectures, 010402 general chemistry, Peptides, Cyclic, 01 natural sciences, lipids, Lipids packing, Static electricity, Electrochemistry, Molecule, General Materials Science, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, MESH: self-assembly, Spectroscopy, chemistry.chemical_classification, Nanotubes, MESH: lipids, Cationic polymerization, Phosphatidylglycerols, Surfaces and Interfaces, self-assembly, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electrostatics, electrostatic interactions, 0104 chemical sciences, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, Membrane, chemistry, Biophysics, peptides, Self-assembly, Somatostatin, 0210 nano-technology
Abstract: International audience; An important aspect of cells is their shape flexibility that gives them motion but also a high adaptation versatility to their environment. This shape versatility is mediated by different types of protein−membrane interactions among which electrostatic plays an important role. In the present work we examined the interaction between a small dicationic peptide, that possesses self-assembly properties, and lipid model membranes. The peptide, lanreotide, spontaneously forms nanotubes in water that have a strictly uniform diameter. In the current work, we show that the interaction between the cationic peptide and negatively charged bilayers of lipids induces the formation of myelin sheath-like structures that we call nanoscrolls. By deciphering the different steps of formation and the molecular structure of the self-assembly, we show how electrostatics modify the spontaneous peptide and lipid way of packing.
Published: 2019

18. Molecular and Material Engineering of Photocathodes Derivatized with Polyoxometalate-Supported {Mo

Author: Jeoffrey, Tourneur, Bruno, Fabre, Gabriel, Loget, Antoine, Vacher, Cristelle, Mériadec, Soraya, Ababou-Girard, Francis, Gouttefangeas, Loic, Joanny, Emmanuel, Cadot, Mohamed, Haouas, Nathalie, Leclerc-Laronze, Clément, Falaise, and Emmanuel, Guillon
Abstract: Molecular engineering of efficient HER catalysts is an attractive approach for controlling the spatial environment of specific building units selected for their intrinsic functionality required within the multistep HER process. As the {Mo
Published: 2019

19. Black Silicon Photoanodes Entirely Prepared with Abundant Materials by Low-Cost Wet Methods

Author: Bruno Fabre, Antoine Vacher, Kiseok Oh, Soraya Ababou-Girard, Francis Gouttefangeas, Benedikt Lassalle-Kaiser, Vincent Dorcet, Loïc Joanny, Gabriel Loget, Cristelle Mériadec, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), ANR (project EASi-NANO) [ANR-16-CE09-0001-01], ANR-16-CE09-0001,EASi-NANO,Nanostructuration Electrochimique du Silicium pour la Fabrication de Surfaces Fonctionnelles à un Coût Réduit(2016), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Fabrication, Materials science, Silicon, Energy Engineering and Power Technology, Nanoparticle, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, 7. Clean energy, water splitting, chemistry.chemical_compound, nickel, Catalytic metal, Materials Chemistry, Electrochemistry, Chemical Engineering (miscellaneous), [CHIM]Chemical Sciences, Electrical and Electronic Engineering, Black silicon, Oxygen evolution, Substrate (chemistry), silicon, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Nickel, chemistry, Chemical engineering, artificial photosynthesis, 0210 nano-technology
Abstract: International audience; We report a new design for water-splitting photoanodes, based on a highly absorbing black silicon (BSi) substrate modified with catalytic metal nanoparticles (NPs). The overall fabrication strategy is cost-efficient as it only requires the use of abundant materials and simple wet procedures such as electrochemical etching and electrodeposition and does not involve the use of a buried homojunction and protection layer. Importantly, these results demonstrate that electrodeposited transition metal NPs can stabilize structured Si photoelectrodes without the need for a protection layer.
Published: 2019

20. Transversal Rotation of Unsymmetrical Bolaamphiphile Molecules in Lamellar Structures

Author: Jeftic, J., Berchel, M., Lemiegre, L., Cristelle Mériadec, Franck ARTZNER, Benvegnu, T., Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Brest (UBO), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), and Jonchère, Laurent
Subjects: [PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract: International audience
Published: 2019

21. A General Concept for Solar Water‐Splitting Monolithic Photoelectrochemical Cells Based on Earth‐Abundant Materials and a Low‐Cost Photovoltaic Panel

Author: Sitthichok Kasemthaveechok, Kiseok Oh, Bruno Fabre, Jean‐François Bergamini, Cristelle Mériadec, Soraya Ababou‐Girard, and Gabriel Loget
Subjects: Renewable Energy, Sustainability and the Environment, General Environmental Science
Published: 2020

22. Casein interaction with lipid membranes: Are the phase state or charge density of the phospholipids affecting protein adsorption?

Author: Berta Gumí-Audenis, Christelle Lopez, Franck Artzner, Cristelle Mériadec, Adrián Crespo-Villanueva, Florence Rousseau, Fausto Sanz, Marina I. Giannotti, Fanny Guyomarc'H, Institute for Bioengineering of Catalonia, Barcelona Institute of Science and Technology (BIST), Material Sciences and Physical Chemistry Department, Universitat de Barcelona, Centro de Investigación Biomédica en Red (CIBER), Instituto de Salud Carlos III (ISC), Science et Technologie du Lait et de l'Oeuf (STLO), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Institute for Bioengineering of Catalonia (IBEC), Universitat de Barcelona (UB), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Centro de Investigación Biomédica en Red, 2016-2017 AIC-P2B, Département Caractérisation et Élaboration des Produits Issus de l’Agriculture, Institut National de la Recherche Agronomique, AGAUR 2017 SG 1442, Generalitat de Catalunya, Ministerio de Economía y Competitividad, Instituto de Salud Carlos III, Instituto de Salud Carlos III [Madrid] (ISC), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), and Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)
Subjects: phospholipide, Lipid Bilayers, Biophysics, Phospholipid, Golgi Apparatus, cellule mammaire, micelle de caséine, 02 engineering and technology, 010402 general chemistry, Endoplasmic Reticulum, Microscopy, Atomic Force, 01 natural sciences, Biochemistry, microscopie à force atomique, chemistry.chemical_compound, Membrane Lipids, membrane lipidique, X-Ray Diffraction, milk protein, protéine du lait, Casein, [SDV.IDA]Life Sciences [q-bio]/Food engineering, diffraction x, phospholipid, Micelles, Phospholipids, [PHYS]Physics [physics], caséine, Calorimetry, Differential Scanning, xrd, Endoplasmic reticulum, Bilayer, Force spectroscopy, membrane de phospholipide, Caseins, Biological membrane, Cell Biology, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Membrane, chemistry, Adsorption, 0210 nano-technology, [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition, Protein adsorption, Protein Binding
Abstract: International audience; Casein micelles are ~200 nm electronegative particles that constitute 80 wt% of the milk proteins. During synthesis in the lactating mammary cells, caseins are thought to interact in the form of ~20 nm assemblies, directly with the biological membranes of the endoplasmic reticulum and/or the Golgi apparatus. However, conditions that drive this interaction are not yet known. Atomic force microscopy imaging and force spectroscopy were used to directly observe the adsorption of casein particles on supported phospholipid bilayers with controlled compositions to vary their phase state and surface charge density, as verified by X-ray diffraction and zetametry. At pH 6.7, the casein particles adsorbed onto bilayer phases with zwitterionic and liquid-disordered phospholipid molecules, but not on phases with anionic or ordered phospholipids. Furthermore, the presence of adsorbed caseins altered the stability of the yet exposed bilayer. Considering their respective compositions and symmetry/asymmetry, these results cast light on the possible interactions of casein assemblies with the organelles' membranes of the lactating mammary cells.
Published: 2018

23. Elucidating the performance and unexpected stability of partially coated water-splitting silicon photoanodes

Author: Kiseok Oh, Gabriel Loget, Soraya Ababou-Girard, Francis Gouttefangeas, Bruno Fabre, Benedikt Lassalle-Kaiser, Loïc Joanny, Cristelle Mériadec, Vincent Dorcet, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Synthèse Caractérisation Analyse de la Matière (ScanMAT), Université de Rennes (UR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), ANR (project EASi-NANO) [ANR-16-CE09-0001-01], Rennes Metropole [AIS 16C402], ANR-16-CE09-0001,EASi-NANO,Nanostructuration Electrochimique du Silicium pour la Fabrication de Surfaces Fonctionnelles à un Coût Réduit(2016), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut de Chimie du CNRS (INC), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Silicon, Passivation, chemistry.chemical_element, Nanoparticle, 02 engineering and technology, engineering.material, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Coating, Etching (microfabrication), Environmental Chemistry, [PHYS]Physics [physics], Aqueous solution, Renewable Energy, Sustainability and the Environment, business.industry, 021001 nanoscience & nanotechnology, Pollution, 0104 chemical sciences, Semiconductor, Nuclear Energy and Engineering, chemistry, Chemical engineering, engineering, Water splitting, 0210 nano-technology, business
Abstract: International audience; H-2 is an ideal energy carrier because it has a high energy density, and it can be easily stored, transported, and readily used to power electrical devices. Like photosynthesis, where photons are converted into energy-rich molecules, sunlight energy can be converted into H-2 and O-2 using photoelectrochemical water splitting cells (PECs). Despite the fact that silicon is considered one of the most attractive semiconductors for manufacturing photoelectrodes, its use is currently limited by its low activity and its instability in aqueous solutions. Herein, we report on surprisingly stable Si-based photoanodes, fabricated by simple aqueous electrodeposition, which results in the partial (
Published: 2018

24. Tailoring the self-assembling abilities of functional hybrid nanomaterials from rod-like to disk-like clustomesogens based on a luminescent {Mo6Br8}(4+) inorganic cluster core

Author: Susanta K. Nayak, Franck Artzner, Maria Amela-Cortes, Aurore Gandubert, Cristelle Mériadec, Stéphane Cordier, Yann Molard, Cristian Vicent, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Synthèse Caractérisation Analyse de la Matière (ScanMAT), Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut de Chimie du CNRS (INC), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Fondation Langlois, MENSR, FP7-PEOPLE-IIF [299527 LH-NANLC], ANR Clustomesogen [ANR-13-BS07-0003-01], ANR-13-BS07-0003,CLUSTOMESOGEN,Cristaux liquides hybrides organiques-inorganiques luminescents contenant des clusters octaédriques de métaux de transition(2013), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], Scaffold, Materials science, Mesogen, Nanotechnology, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Nanomaterials, Core (optical fiber), Octahedron, Materials Chemistry, Cluster (physics), 0210 nano-technology, Luminescence, Hybrid material
Abstract: International audience; Self-organizing processes are elegant ways to generate and control the nanostructuration of hybrid materials. We describe in this work the synthesis, self-organizing abilities and photo-physical properties of (nBu(4)N)(2)[Mo6Br8i(L)(a)(6)] clustomesogens containing 18 cyanobiphenyl (CB) mesogenic moieties spread equally around the metallic scaffold via aliphatic spacers. By controlling the spacer length and thus the mesogenic density around the rigid inorganic bulky scaffold, we tailored the morphology of hybrid supermolecular building blocks from rod-like to disk-like which strongly influenced their self-organizing abilities. The photophysical properties of hybrids were investigated in their glassy state and in solution. Temperature studies reveal different behaviours depending on the hybrid nanostructuration. Despite their isotropic nature, octahedral clusters offer numerous possibilities in the design of self-assembled hybrid materials showing strong luminescence properties, which is of particular interest in the fields of optics or optoelectronics.
Published: 2018

25. A General Concept for Solar Water-Splitting Monolithic Photoelectrochemical Cells Based on Earth-Abundant Materials and a Low-Cost Photovoltaic Panel

Author: Kiseok Oh, Gabriel Loget, Cristelle Mériadec, Jean-François Bergamini, Soraya Ababou-Girard, Bruno Fabre, Sitthichok Kasemthaveechok, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), ANR (project EASi-NANO) [ANR-16-CE09-0001-01], Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), ANR. Grant Number: ANR-16-CE09-0001-01, ANR-16-CE09-0001,EASi-NANO,Nanostructuration Electrochimique du Silicium pour la Fabrication de Surfaces Fonctionnelles à un Coût Réduit(2016), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
Subjects: Materials science, Silicon, Earth abundant, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, 7. Clean energy, water splitting, Artificial photosynthesis, Solar water, nickel Alike photosynthesis, nickel, [CHIM]Chemical Sciences, General Environmental Science, sunlight energy, [PHYS]Physics [physics], Renewable Energy, Sustainability and the Environment, Photovoltaic system, silicon, Photoelectrochemical cell, 021001 nanoscience & nanotechnology, Engineering physics, 0104 chemical sciences, Nickel, chemistry, artificial photosynthesis, Water splitting, 0210 nano-technology, where light is transformed into energy-rich molecules
Abstract: International audience; Like photosynthesis, where light is transformed into energy-rich molecules, sunlight energy can be converted into H-2 and O-2 using water-splitting photoelectrochemical cells (PECs). These systems are highly promising to produce H-2 without carbon emissions, however, their fabrication is still based on expensive fabrication procedures and nonabundant materials, which prevents their manufacturing and study by many laboratories. Here, an original concept for preparing monolithic water-splitting PECs based on the integration of a low-cost Si photovoltaic (PV) panel with two Si-based photoelectrodes fabricated by simple procedures and earth-abundant materials is demonstrated. In contrast with previous approaches, in the present system, the PV solid junction and the two solid/liquid junctions participate in the creation of the effective photovoltage applied for water splitting. This simple device that can split water from various electrolytes for several hours should promote new advances in the field of solar fuels.
Published: 2018

26. Dispersed Ni nanoparticles stabilize silicon photoanodes for efficient and inexpensive sunlight-assisted water oxidation

Author: Cristelle Mériadec, Gabriel Loget, Stéphanie Fryars, Bruno Fabre, Soraya Ababou-Girard, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), ANR-16-CE09-0001-01, Agence Nationale de la Recherche, AIS 16C402, Rennes M?tropole, ANR-16-CE09-0001,EASi-NANO,Nanostructuration Electrochimique du Silicium pour la Fabrication de Surfaces Fonctionnelles à un Coût Réduit(2016), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Silicon, Passivation, Energy Engineering and Power Technology, chemistry.chemical_element, Nanoparticle, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Catalysis, Materials Chemistry, [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS, Aqueous solution, Renewable Energy, Sustainability and the Environment, Oxygen evolution, Photoelectrochemical cell, 021001 nanoscience & nanotechnology, Solar fuel, 0104 chemical sciences, Fuel Technology, Chemical engineering, chemistry, Chemistry (miscellaneous), 0210 nano-technology
Abstract: Ni electrodeposited on n-type Si from aqueous solutions in the form of isolated or coalescent nanoparticles (NPs) protects the underlying and partially exposed Si from photocorrosion-induced electrical passivation. Such photoanodes, fabricated without the need for additional protecting layers, a buried junction, and high-vacuum techniques, show a high photovoltage of ∼500 mV for the oxygen evolution reaction (OER), state-of-the-art photocurrents, and faradaic efficiencies > 90% under AM 1.5G illumination conditions at pH 14. Remarkably, these photoelectrodes are stable and can be operated at the light-limited catalytic current from 10 h to more than 40 h in 1 M NaOH. These findings demonstrate that robust and efficient Si-based photoanodes can be produced easily, which opens new opportunities for the implementation of low-cost Si-based monolithic photoelectrochemical cells for efficient solar fuel production.
Published: 2017

27. Mechanical properties of membranes composed of gel-phase or fluid-phase phospholipids probed on liposomes by atomic force spectroscopy

Author: Nicolas Delorme, Cédric Gaillard, Christelle Lopez, Franck Artzner, Oumaima Et-Thakafy, Fanny Guyomarc'H, Cristelle Mériadec, Science et Technologie du Lait et de l'Oeuf (STLO), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institut des Molécules et Matériaux du Mans (IMMM), Le Mans Université (UM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Unité de recherche sur les Biopolymères, Interactions Assemblages (BIA), Institut National de la Recherche Agronomique (INRA), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), The Asylum Research MFP3D-BIO atomic force microscope was funded by the European Union (FEDER), the French Ministry of Education and Research, INRA, Conseil Général 35 and Rennes Métropole. The doctoral fellowship of author Et-Thakafy was funded by INRA CEPIA and Région Bretagne under the grant ARED 8806., Le Mans Université (UM)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: phospholipide, x ray, rayon x, Lipid Bilayers, Analytical chemistry, diffraction, 02 engineering and technology, Microscopy, Atomic Force, 010402 general chemistry, vésicule phospholipidique, 01 natural sciences, Adsorption, membrane lipidique, lipid, Microscopy, Electrochemistry, General Materials Science, Lipid bilayer, Phospholipids, Spectroscopy, lipide, Mechanical Phenomena, [PHYS]Physics [physics], Liposome, Chemistry, Spectrum Analysis, Force spectroscopy, technology, industry, and agriculture, Surfaces and Interfaces, Penetration (firestop), [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, diffraction électronique, Membrane, [CHIM.POLY]Chemical Sciences/Polymers, Electron diffraction, Liposomes, liposome, Phosphatidylcholines, electron diffraction, lipids (amino acids, peptides, and proteins), spectroscopie à force atomique, 0210 nano-technology
Abstract: International audience; In many liposome applications, the nanomechanical properties of the membrane envelope are essential to ensure, e.g., physical stability, protection, or penetration into tissues. Of all factors, the lipid composition and its phase behavior are susceptible to tune the mechanical properties of membranes. To investigate this, small unilamellar vesicles (SUV; diameter < 200 nm), referred to as liposomes, were produced using either unsaturated 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) or saturated 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) in aqueous buffer at pH 6.7. The respective melting temperatures of these phospholipids were −20 and 41 °C. X-ray diffraction analysis confirmed that at 20 °C DOPC was in the fluid phase and DPPC was in the gel phase. After adsorption of the liposomes onto flat silicon substrates, atomic force microscopy (AFM) was used to image and probe the mechanical properties of the liposome membrane. The resulting force–distance curves were treated using an analytical model based on the shell theory to yield the Young’s modulus (E) and the bending rigidity (kC) of the curved membranes. The mechanical investigation showed that DPPC membranes were much stiffer (E = 116 ± 45 MPa) than those of DOPC (E = 13 ± 9 MPa) at 20 °C. The study demonstrates that the employed methodology allows discrimination of the respective properties of gel- or fluid-phase membranes when in the shape of liposomes. It opens perspectives to map the mechanical properties of liposomes containing both fluid and gel phases or of biological systems.
Published: 2017

28. Time-dependent phase diagram of bolaamphiphile molecules presenting various lamellar structures

Author: Jeftic, J., Berchel, M., Lemiègre, L., Cristelle Mériadec, Franck ARTZNER, Benvegnu, T., Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), and Jonchère, Laurent
Subjects: [PHYS]Physics [physics], ComputingMilieux_MISCELLANEOUS, [PHYS] Physics [physics]
Abstract: International audience
Published: 2017

29. Assembly of Platinum Diimine Dithiolate Complexes onto Hydrogen-Terminated Silicon Surfaces

Author: Vincent Dorcet, Thierry Roisnel, Bruno Fabre, Dominique Lorcy, Cristelle Mériadec, Gilles Yzambart, Soraya Ababou-Girard, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: organometallic electrochemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Hydrosilylation, Organic Chemistry, chemistry.chemical_element, Crystal structure, Photochemistry, Inorganic Chemistry, Bipyridine, chemistry.chemical_compound, chemistry, Radical ion, Covalent bond, Polymer chemistry, Physical and Theoretical Chemistry, Cyclic voltammetry, Platinum, Diimine
Abstract: International audience; The synthesis and structural characterization of the platinum diimine dithiolate complexes [Pt(R2bipy)(dmipi)] (dmipi = 4,5-dimercapto-l,3-dithiol-2-propargylimino and R = H, tBu) are described together with the X-ray crystal structure of the dithiolate proligand. These heteroleptic Pt complexes have been covalently bound to hydrogen-terminated silicon (100) surfaces using either a one-step or two-step procedure. The redox-active organometallic film modified surfaces were prepared from a hydrosilylation reaction at 90 °C of either the Pt complex bearing an ethyne terminal group or an ethyne-terminated dithiolate precursor followed by the subsequent anchoring of the Pt complex. Cyclic voltammetry measurements showed the presence of a single reversible one-electron-oxidation process corresponding to the oxidation of the complex into its radical cation species at 0.42 and 0.46 V vs SCE for the unsubstituted and tBu-substituted bipyridine dithiolate Pt complex-modified Si(100) surfaces, respectively. Such values compare well with those determined for the electroactive molecules in solution. Moreover, FTIR spectroscopy and X-ray photoelectron spectroscopy (XPS) measurements were consistent with the expected structure of grafted molecular chains and revealed a significant oxidation of the underlying silicon surface. Nevertheless, the one-step procedure was found to lead to redox-active films of density higher than those produced from the two-step procedure. From XPS data, the surface coverage was estimated at 0.10 and in the range 0.03–0.06 Pt complex per surface silicon atom for the one-step and two-step procedures, respectively.
Published: 2014

30. Cover Feature: Boosting the Performance of BiVO 4 Prepared through Alkaline Electrodeposition with an Amorphous Fe Co‐Catalyst (ChemElectroChem 3/2019)

Author: Gabriel Loget, Stéphanie Fryars, Cristelle Mériadec, Rawa Abdallah, Soraya Ababou-Girard, Hiba Saada, Didier Floner, Vincent Dorcet, Antoine Vacher, and Bruno Fabre
Subjects: chemistry.chemical_compound, Materials science, Chemical engineering, chemistry, Bismuth vanadate, Electrochemistry, Water splitting, Catalysis, Amorphous solid
Published: 2019

31. Water soluble polymer–surfactant complexes-stabilized Pd(0) nanocatalysts: Characterization and structure–activity relationships in biphasic hydrogenation of alkenes and α,β-unsaturated ketones

Author: Josiel B. Domingos, Alain Roucoux, Audrey Denicourt-Nowicki, Brunno L. Albuquerque, Cristelle Mériadec, Institut des Sciences Chimiques de Rennes ( ISCR ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Ecole Nationale Supérieure de Chimie de Rennes-Institut National des Sciences Appliquées ( INSA ) -Centre National de la Recherche Scientifique ( CNRS ), Departamento Física [Florianópolis], Universidade Federal de Santa Catarina [Florianópolis] ( UFSC ), Institut de Physique de Rennes ( IPR ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Centre National de la Recherche Scientifique ( CNRS ), We are grateful to CNPq and CAPES for financial support received for this study under the Science Without Borders Program (SWE 200723/2014-6). This work was also supported by the Brazilian Synchrotron Light Laboratory (LNLS) under proposal SAXS1-15973 (beam time usage) and the Central Laboratory of Electron Microscopy (LCME) at UFSC (TEM analysis). The authors are indebted to Patricia Beaunier from Université Pierre et Marie Curie (UMPC) for transmission electron microscopy analysis and Franck Artzner from Institut de Physique at Université de Rennes for additional SAXS analysis and discussions., Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Universidade Federal de Santa Catarina = Federal University of Santa Catarina [Florianópolis] (UFSC), Institut de Physique de Rennes (IPR), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Supramolecular chemistry, chemistry.chemical_element, Nanoparticle, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, [ CHIM ] Chemical Sciences, Catalysis, Supramolecular self-assemblies, Surfactant, [CHIM]Chemical Sciences, Organic chemistry, Physical and Theoretical Chemistry, Polymer, chemistry.chemical_classification, Substrate (chemistry), Water, 021001 nanoscience & nanotechnology, palladium, Nanomaterial-based catalyst, 0104 chemical sciences, [ CHIM.POLY ] Chemical Sciences/Polymers, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, nanoparticles, Hydrogenation, 0210 nano-technology, Selectivity, Palladium
Abstract: International audience; A suitable approach to stabilize palladium nanoparticles in water as a green reaction medium for catalytic hydrogenation reactions is described. Supramolecular self-assemblies, obtained through the mixture of modified polyethyleneimines as amphiphilic polymers and water-soluble ammonium salts as surfactants, were used as efficient protective agents in the synthesis of Pd(0) nanospecies. The size and dispersion of the nanoparticles prepared with these original self-assemblies were characterized by TEM, SAXS and DLS techniques. The performances of the catalysts according to the polymer–surfactant mixtures were investigated in the hydrogenation of alkenes and α,β-unsaturated ketones in pure biphasic water/substrate medium, under mild conditions (room temperature and 1 bar H2). The nanocatalysts showed efficient catalytic activities and selectivity towards CC bonds. From investigations, the polymer–surfactant complexes act as cooperative protective agents and a pertinent structure–activity relationship was proposed based on the zeta-potential values and the catalytic activity of the resulting colloids
Published: 2016

32. Electrokinetic analysis of PES/PVP membranes aged by sodium hypochlorite solutions at different pH

Author: Kamel Baddari, Murielle Rabiller-Baudry, Soraya Ababou-Girard, Patrick Loulergue, Yamina Hanafi, Cristelle Mériadec, Anthony Szymczyk, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), UR- MPE (Université M'hamed Bougara de Boumerdes, Unité de Recherche Matériaux, Procèdes et Environnement UR- MPE, Algérie), UR- MPE, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Financial support from the French National Research Agency is gratefully acknowledged (project MEDUSE-no. ANR-09-BLAN-0055-01)., ANR-09-BLAN-0055,MéDUSE,Approche Multi-Echelle de la dégradation en conditions d'USagE de membranes polymères de filtration(2009), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Radical, Inorganic chemistry, Synthetic membrane, Ultrafiltration, Filtration and Separation, 02 engineering and technology, 010501 environmental sciences, 01 natural sciences, Biochemistry, Electrokinetic phenomena, chemistry.chemical_compound, Phenol, [CHIM]Chemical Sciences, General Materials Science, Polymer membranes, Physical and Theoretical Chemistry, 0105 earth and related environmental sciences, Chemistry, 021001 nanoscience & nanotechnology, Free radical scavenger, Electrokinetics, Ageing, Sodium hypochlorite, Membrane, Isoelectric point, 0210 nano-technology
Abstract: International audience; This study focused on the impact of ageing solution pH (200 ppm TFC sodium hypochlorite) on the electrokinetic properties of a commercial PES/PVP UF membrane. PVP oxidation, leading to an increase in the negative charge density of aged membranes, was pointed out whatever the ageing solution pH although different mechanisms might be involved depending on the ageing pH. PES degradation was also demonstrated. Electrokinetic measurements highlighted the formation of functional groups with very weak acid properties on the surface of membranes aged in sodium hypochlorite at pH 8.0 and to a lesser extent at pH 6.0 and 11.5. These results were found to be consistent with the formation of phenol groups due to the radical hydroxylation of PES aromatic rings. Moreover, the disappearance of the isoelectric point of membranes aged in sodium hypochlorite at pH 6.0 and 8.0 gave evidence for the formation of strong acid groups such as sulfonic acids. These results suggested some PES-chain scissions, which was confirmed by XPS measurements. The disappearance of the isoelectric point was not observed for membranes aged in sodium hypochlorite at pH 11.5, thus indicating that ClO− was not involved in PES-chain scissions for the ageing conditions considered in this work. Finally, electrokinetic measurements performed with the addition of tertiobutanol (free radical scavenger) and thermo-oxidation experiments revealed for the first time that, although both HClO and free radicals species contributed to PES-chain scissions, HClO had the greater impact on PES degradation.
Published: 2016

33. Magnetically Recoverable Palladium(0) Nanocomposite Catalyst for Hydrogenation Reactions in Water

Author: Audrey Denicourt-Nowicki, Cristelle Mériadec, Carl-Hugo Pélisson, Alain Roucoux, Jean-Marc Greneche, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Institut des Molécules et Matériaux du Mans (IMMM), Le Mans Université (UM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université européenne de Bretagne - European University of Brittany (UEB), MAGFOCAT, Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes-Centre National de la Recherche Scientifique (CNRS), Le Mans Université (UM)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Nanocomposite, Materials science, Organic Chemistry, Inorganic chemistry, Nanoparticle, chemistry.chemical_element, Maghemite, engineering.material, 7. Clean energy, 6. Clean water, Catalysis, Nanomaterial-based catalyst, Inorganic Chemistry, X-ray photoelectron spectroscopy, chemistry, engineering, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, Spectroscopy, ComputingMilieux_MISCELLANEOUS, Palladium
Abstract: International audience; An easy and straightforward strategy has been used for loading palladium(0) nanoparticles onto the magnetic surface of maghemite (γ-Fe2O3), without the use of organic modifiers. The nanocomposite was fully characterized by TEM, XRD, 57Fe Mössbauer spectroscopy, X-ray photoelectron spectroscopy, and superconducting quantum interference device measurements. The Pd0@γ-Fe2O3 nanocatalyst has been investigated in various catalytic reactions, under mild conditions (100 kPa H2, RT), and in neat water. Relevant catalytic activities were achieved in the hydrogenation of olefinic substrates, as well as in hydrodehalogenation reactions of halogenoarenes, that constitutes a promising process for wastewater treatment. These nanocatalysts proved also pertinent for the reduction of nitroarene derivatives into the corresponding anilines, which are promising substrates for fine chemistry. Finally, these catalysts proved to be easily recoverable through the use of an external magnet, without significant loss of activity.
Published: 2015

34. Influence of the electrografting method on the performances of a flow electrochemical sensor using modified electrodes for trace analysis of copper (II)

Author: Cecilia Cristea, Robert Săndulescu, Cristelle Mériadec, Florence Geneste, Ionel Fizesan, Bogdan Feier, Soraya Ababou Girard, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Cluj-Napoca, facultatea, Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), This paper was published under the frame of European Social Found, Human Resources Development Operational Programme 2007–2013, Project No. POSDRU/159/1.5/S/136893. The authors are also thankful for the financial support to 'Iuliu Hatieganu' University of Medicine and Pharmacy of Cluj-Napoca, for the research Grant 1491/8/28.01.2014 and for their help to Ioana Băjan, Ana Gui and Ioana Ionel, students of 'Iuliu Hatieganu' University of Medicine and Pharmacy, Faculty of Pharmacy., Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Copper detection, [CHIM.ORGA]Chemical Sciences/Organic chemistry, General Chemical Engineering, Electrografting, Inorganic chemistry, Open circuit preconcentration, chemistry.chemical_element, Electrochemistry, Copper, Analytical Chemistry, Electrochemical gas sensor, chemistry.chemical_compound, chemistry, Electrode, Cyclam, Graphite, Cyclic voltammetry, Voltammetry, Sensor
Abstract: The performances of carboxylate- and cyclam-modified graphite felt electrodes prepared by different electrografting methods for trace analysis of copper (II) were compared to determine the influence of the immobilization process of the linkers on the sensor properties. The derivatization performed by cathodic reduction of diazonium salts and by anodic oxidation of amines in organic and aqueous media was first evaluated by cyclic voltammetry and X-ray photoelectron spectroscopy analyses, showing a higher surface coverage for the reduction process. Cyclam was subsequently attached on the COOH-modified graphite felts by a coupling reaction. The modified electrodes were then employed in a flow analytical system for trace analysis of copper (II) ions. The influence of the surface coverage and the nature of the linker on the electrochemical signal obtained by linear sweep stripping voltammetry analysis after a preconcentration step performed at open circuit was highlighted. The selectivity estimated in the presence of lead used as a common ion interferent was higher when a selective receptor was used and depends on the nature of the linker.
Published: 2015

35. Deepin situdry-etch monitoring of III-V multilayer structures using laser reflectometry and reflectivity modeling

Author: H. Moussa, Isabelle Sagnes, Cristelle Mériadec, R. Daneau, L. Manin, and Rama Raj
Subjects: Materials science, business.industry, Surfaces and Interfaces, Nitride, Condensed Matter Physics, Distributed Bragg reflector, Laser, Surfaces, Coatings and Films, Vertical-cavity surface-emitting laser, law.invention, Optics, Stack (abstract data type), Etching (microfabrication), law, Deep reactive-ion etching, Optoelectronics, Dry etching, business
Abstract: Deep reactive ion etching of III-V multilayer structures is an important issue for long wavelength vertical cavity surface emitting laser (VCSELs) where full laser structures are usually very thick. Test etchings were performed on GaAs/AlxGa1−xAs Bragg mirror structures and monitored using laser reflectometry at 651.4 nm. In order to perform very deep etching, up to 9 μm, we designed and fabricated a special two-level mask made up of a thick nitride layer and a thin nickel layer. The etching rate is a complex function of many parameters and may change from run to run for similar structures. Therefore, it is important to have a method to control accurately the process in situ by continuously matching, experimental curves with the results of the reflectivity modeling. Here, we present a model, based on the Abeles matrix method, of the normal incidence reflectivity of a multilayer stack as a function of etch depth. Comparison between the model and the observed reflectivity variation during etching makes it p...
Published: 2002

36. Effects of a Novel Archaeal Tetraether-based Colipid on the In Vivo Gene Transfer Activity of Two Cationic Amphiphiles

Author: Thierry Benvegnu, Tony Le Gall, Franck Artzner, Paul-Alain Jaffrès, Sylvain Barrier, Deborah R. Gill, Mathieu Berchel, Loïc Lemiègre, Cristelle Mériadec, Julie Barbeau, Claude Férec, Tristan Montier, Pierre Lehn, Jelena Jeftić, Stephen C. Hyde, Génétique, génomique fonctionnelle et biotechnologies (UMR 1078) (GGB), Institut Brestois Santé Agro Matière (IBSAM), Université de Brest (UBO)-Université de Brest (UBO)-EFS-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Chimie, Electrochimie Moléculaires et Chimie Analytique (CEMCA), Université de Brest (UBO)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Gene Medicine Group, Nuffield Division of Clinical Laboratory Sciences, 'Association Française contre les Myopathies' (Evry, France), 'Vaincre La Mucoviscidose' (Paris, France), 'Association de Transfusion Sanguine et de Biogénétique Gaétan Saleün' (Brest, France), 'Conseil Régional de Bretagne', 'Brest Métropole Océane'., EFS-Université de Brest (UBO)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut Brestois Santé Agro Matière (IBSAM), Université de Brest (UBO), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Brest (UBO)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Brestois Santé Agro Matière (IBSAM), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Genetic enhancement, Pharmaceutical Science, Gene delivery, Biology, 010402 general chemistry, DNA condensation, Transfection, 01 natural sciences, cystic fibrosis, 03 medical and health sciences, chemistry.chemical_compound, Mice, Surface-Active Agents, In vivo, Cations, Drug Discovery, Amphiphile, Animals, gene delivery, 030304 developmental biology, 0303 health sciences, Liposome, tetraether, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Cationic polymerization, Gene Transfer Techniques, DNA, Archaea, Lipids, 0104 chemical sciences, colipid, chemistry, Biochemistry, Archaeosome, Liposomes, Molecular Medicine, Female, Ethers
Abstract: International audience; Gene therapy for treating inherited diseases like cystic fibrosis might be achieved using multi-modular non-viral lipid-based systems. To date, most optimizations have concerned cationic lipids rather than colipids. In this study, an original archaeal tetraether derivative was used as a colipid in combination with one or the other of two monocationic amphiphiles. The liposomes obtained, termed archaeosomes, were characterized regarding lipid self-assembling properties, macroscopic/microscopic structures, DNA condensation/neutralization/relaxation abilities, and colloidal stability in presence of serum. In addition, gene transfer experiments were conducted in mice with lipid/DNA complexes being administered via systemic or local delivery routes. Altogether, the results showed that the tetraether colipid can provide complexes with different in vivo transfection abilities depending on the lipid combination, the lipid/colipid molar ratio, and the administration route. This original colipid appears thus as an innovative modular platform endowed with properties possibly beneficial for fine-tuning of in vivo lipofection and other biomedical applications.
Published: 2014

37. Thermotropic Luminescent Clustomesogen Showing a Nematic Phase: A Combination of Experimental and Molecular Simulation Studies

Author: Yann Molard, Franck Artzner, Cristelle Mériadec, Marianne E. Prévôt, Maria Amela Cortes, Régis Gautier, Viorel Cîrcu, Stéphane Cordier, Bruno Fontaine, Florent Goujon, Hervé Folliot, Aziz Ghoufi, Frederick Dorson, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Fonctions Optiques pour les Technologies de l'informatiON (FOTON), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université européenne de Bretagne - European University of Brittany (UEB)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de Clermont-Ferrand (ICCF), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-SIGMA Clermont (SIGMA Clermont)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Dept. of Inorganic Chemistry, University of Bucharest (UniBuc), ANR-13-BS07-0003,CLUSTOMESOGEN,Cristaux liquides hybrides organiques-inorganiques luminescents contenant des clusters octaédriques de métaux de transition(2013), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Université européenne de Bretagne - European University of Brittany (UEB)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Luminescent, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, Molecular Dynamics, 01 natural sciences, Thermotropic crystal, Catalysis, Nanoclusters, Cluster Compounds, Molecular dynamics, Liquid crystal, Phase (matter), Organic chemistry, Clustomesogen, Chemistry, Mesogen, Organic Chemistry, General Chemistry, Self-assembly, 021001 nanoscience & nanotechnology, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Crystallography, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Hybrid materials, 0210 nano-technology, Hybrid material, Thermotropic
Abstract: International audience; Octahedral Mo6 nanoclusters are functionalized with two organic ligands containing cyanobiphenyl (CB) units, giving luminescent hybrid liquid crystals (LC). Although the mesogenic density around the bulky inorganic core is constant, the two hybrids show different LC properties. Interestingly, one of them shows a nematic phase, which is particularly rare for this kind of supermolecular system. This surprising result is explained by using large-scale molecular dynamic simulations.
Published: 2014

38. Hexacyano octahedral metallic clusters as versatile building blocks in the design of extended polymeric framework and clustomesogens

Author: Franck Artzner, Stéphane Cordier, Yann Molard, Cristelle Mériadec, Maria Amela-Cortes, Nikolay G. Naumov, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Nikolaev Institute of Inorganic Chemistry [Novosibirsk] (NIC), Siberian Branch of the Russian Academy of Sciences (SB RAS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Magnetism, Ionic bonding, Nanotechnology, General Chemistry, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, Octahedron, Transition metal, Chemical engineering, Liquid crystal, Materials Chemistry, Cluster (physics), Luminescence, Hybrid material
Abstract: International audience; Using self-assembling processes to generate hybrid organic inorganic materials allows the control of their structuration at the nanometric scale. We describe in this work the synthesis, liquid crystal and photo-physical properties of [M6Qi8(CN)a6]n- (M = Mo, Re; Qi = Br, Se; n = 2, 3 or 4) cluster anionic units containing clustomesogens. A new and efficient synthetic route was developed to synthesize the [Mo6Bri8(CN)a6]2- building block that is stable in water solution and that could be crystallized as the porous [trans-Cd(H2O)2][Mo6Bri8(CN)a6]. Hybrids were obtained by a metathesis reaction with a specifically designed organic cation. Their self-assembling abilities can be tailored by playing with the charge of the inorganic building blocks going from a nematogenic behaviour, which is particularly rare for ionic mesomorphic material, to the formation of layered structures. The intrinsic properties (luminescence or magnetism) of transition metal clusters are well retained in the hybrid matrices. The nanostructuration of the material influences its ability to emit light despite the isotropy of the emissive nanocluster. Finally, we demonstrate that the magnetic [Re6Se8CN6]3- can be reduced into the luminescent [Re6Se8CN6]4- upon heating at 150 [degree]C. These hybrid materials show promising prospects in the field of luminescent material.
Published: 2014

39. Experimental observation of double-walled peptide nanotubes and monodispersity modeling of the number of walls

Author: Franck Artzner, Camille Delvaux, Nicolas Fay, Frédéric Gobeaux, Cristelle Mériadec, Jean-Christophe Cintrat, Céline Valéry, Christophe Tarabout, Florian Meneau, Maïté Paternostre, Institut de Biologie et de Technologies de Saclay (IBITECS), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Ipsen-Pharman, Ipsen-Pharma, Commissariat à l'énergie atomique et aux énergies alternatives, Région Bretagne, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Models, Molecular, Work (thermodynamics), LIPID TUBULES, Surface Properties, OCTAPEPTIDE, Dispersity, Molecular Conformation, Nanotechnology, 02 engineering and technology, ARCHITECTURES, 010402 general chemistry, 01 natural sciences, Divalent, MOLECULES, Electrochemistry, Molecule, General Materials Science, Particle Size, Spectroscopy, chemistry.chemical_classification, ELECTRON-MICROSCOPY, COUNTERIONS, PACKING, Nanotubes, Biomolecule, Chemical modification, Surfaces and Interfaces, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, Membrane, chemistry, SINGLE, Chemical physics, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Counterion, MEMBRANE, 0210 nano-technology, Peptides
Abstract: International audience; Self-assembled nanoarchitectures based on biological molecules are attractive because of the simplicity and versatility of the building blocks. However, size control is still a challenge. This control is only possible when a given system is deeply understood. Such is the case with the lanreotide acetate, an octapeptide salt that spontaneously forms monodisperse nanotubes when dissolved into pure water. Following a structural approach, we have in the past demonstrated the possibility to tune the diameter of these nanotubes while keeping a strict monodispersity, either by chemical modification of one precise amino acid on the peptide sequence or by changing the size of the counterions. On the basis of these previous studies, we replaced monovalent counterions by divalent ones to vary the number of walls. Indeed, in the present work, we show that lanreotide associated with a divalent counterion forms double-walled nanotubes while keeping the average diameter constant. However, the strict monodispersity of the number of walls was unexpected. We propose that the divalent counterions create an adhesion force that can drive the wall packing. This adhesion force is counterbalanced by a mechanical one that is related to the stiffness of the peptide wall. By taking into account these two opposite forces, we have built a general model that fully explains why the lanreotide nanotubes formed with divalent counterions possess two walls and not more.
Published: 2013

40. Electroless patterned assembly of metal nanoparticles on hydrogen-terminated silicon surfaces for applications in photoelectrocatalysis

Author: Bruno Fabre, Soraya Ababou-Girard, Cristelle Mériadec, Leila Hennous, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), CNRS, UMR 6226, Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, electron spectroscopy (XPS), Silicon, Scanning electron microscope, Analytical chemistry, chemistry.chemical_element, electron microscopy (SEM), 02 engineering and technology, 010402 general chemistry, Electrocatalyst, Platinum nanoparticles, 01 natural sciences, Metal, electrocatalysis, General Materials Science, galvanic displacement, Deposition (law), 021001 nanoscience & nanotechnology, 0104 chemical sciences, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, chemistry, Colloidal gold, visual_art, gold nanoparticles, silicon surfaces, visual_art.visual_art_medium, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 0210 nano-technology, Platinum, platinum nanoparticles
Abstract: International audience; The deposition of gold and platinum nanoparticles (NPs) on hydrogen-terminated Si(100) (Si(100)-H) surfaces has been performed by galvanic displacement using fluoride-free sub-millimolar metallic salt solutions. The scanning electron microscopy (SEM) images showed the formation of oblate hemispherical NPs, with an average diameter of ca. 40 nm and an average height of 20 ± 10 and 10 ± 5 nm for Au and Pt, respectively. Furthermore, the calculated number density was (6.0 ± 0.8) × 10(9) Au NPs cm(-2) and (6.6 ± 1.3) × 10(9) Pt NPs cm(-2) with a larger size distribution measured for Au NPs. The Au 4f and Pt 4f X-ray photoelectron spectra of the metallized surfaces were characterized by a principal component corresponding to either the metallic gold or platinum. However, two other components located at higher binding energies were also visible and ascribed to gold or platinum silicides. Using this fluoride-free deposition process and a "reagentless" UV photolithography technique, we have also demonstrated that it was possible to prepare metallic NP micropatterns. Following this approach, single metal (Au) and two metals (Au and Pt) patterns have been produced and characterized by energy-dispersive X-ray spectroscopy (EDS) which revealed the presence of the expected metal(s). Such metallic NP micropatterned surfaces were used as photocathodes for H(2) evolution from water as a proof-of-concept experiment. These electrodes exhibited much higher electrocatalytic performance than that of nonmetallized Si(100)-H, both in the absence of light and under illumination. The overpotential for hydrogen evolution was significantly decreased by ca. 450 mV with respect to Si(100)-H (measured for a current density of 0.1 mA cm(-2)) under identical illumination conditions.
Published: 2013

41. Near-infrared chiro-optical effects in metallogels

Author: Sisir Debnath, Cristelle Mériadec, Jean-François Bergamini, Marc Fourmigué, Franck Camerel, Franck Artzner, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Right handed, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Near-infrared spectroscopy, Metals and Alloys, Nanotechnology, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Catalysis, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Crystallography, Materials Chemistry, Ceramics and Composites, 0210 nano-technology
Abstract: International audience; A series of novel metallogelators containing near-IR nickel-bis(dithiolene) absorbers were rationally designed and synthesized. Robust gel networks are formed by right handed helical 1D-nanofibers which generate strong and remarkable chiro-optical effects in the near-infrared region.
Published: 2012

42. Structural role of counterions adsorbed on self-assembled peptide nanotubes

Author: Nicolas Fay, Frédéric Gobeaux, Florian Meneau, Céline Valéry, Christophe Tarabout, Melinda Ligeti, David-Alexandre Buisson, Maïté Paternostre, Cristelle Mériadec, Lionel Perrin, Franck Artzner, Jean-Christophe Cintrat, Khac Minh Huy Nguyen, Institut de Biologie et de Technologies de Saclay (IBITECS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Ipsen-Pharman, Ipsen-Pharma, Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Models, Molecular, inorganic chemicals, Stereochemistry, MESH: Somatostatin, Molecular Conformation, Context (language use), MESH: Amino Acid Sequence, 010402 general chemistry, 01 natural sciences, Biochemistry, Peptides, Cyclic, Catalysis, chemistry.chemical_compound, Colloid and Surface Chemistry, Physisorption, Amino Acid Sequence, MESH: Peptides, Cyclic, chemistry.chemical_classification, MESH: Molecular Conformation, Nanotubes, 010405 organic chemistry, MESH: Peptides, Cationic polymerization, General Chemistry, Electrostatics, 0104 chemical sciences, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, Monomer, chemistry, Counterion condensation, Chemisorption, Chemical physics, Adsorption, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Counterion, MESH: Adsorption, Peptides, Somatostatin, MESH: Nanotubes, MESH: Models, Molecular
Abstract: International audience; Among noncovalent forces, electrostatic ones are the strongest and possess a rather long-range action. For these reasons, charges and counterions play a prominent role in self-assembly processes in water and therefore in many biological systems. However, the complexity of the biological media often hinders a detailed understanding of all the electrostatic-related events. In this context, we have studied the role of charges and counterions in the self-assembly of lanreotide, a cationic octapeptide. This peptide spontaneously forms monodisperse nanotubes (NTs) above a critical concentration when solubilized in pure water. Free from any screening buffer, we assessed the interactions between the different peptide oligomers and counterions in solutions, above and below the critical assembly concentration. Our results provide explanations for the selection of a dimeric building block instead of a monomeric one. Indeed, the apparent charge of the dimers is lower than that of the monomers because of strong chemisorption. This phenomenon has two consequences: (i) the dimer-dimer interaction is less repulsive than the monomer-monomer one and (ii) the lowered charge of the dimeric building block weakens the electrostatic repulsion from the positively charged NT walls. Moreover, additional counterion condensation (physisorption) occurs on the NT wall. We furthermore show that the counterions interacting with the NTs play a structural role as they tune the NTs diameter. We demonstrate by a simple model that counterions adsorption sites located on the inner face of the NT walls are responsible for this size control.
Published: 2012

43. Stereochemical effect revealed in self-assemblies based on archaeal lipid analogues bearing a central five-membered carbocycle: a SAXS study

Author: Thierry Benvegnu, Loïc Lemiègre, Cristelle Mériadec, Alicia Jacquemet, Franck Artzner, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Models, Molecular, Stereochemistry, Supramolecular chemistry, Molecular Conformation, 02 engineering and technology, Cyclopentanes, 010402 general chemistry, 01 natural sciences, chemistry.chemical_compound, X-Ray Diffraction, Lyotropic, Scattering, Small Angle, Electrochemistry, General Materials Science, Cyclopentane, Spectroscopy, Alkyl, chemistry.chemical_classification, Small-angle X-ray scattering, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Diastereomer, Temperature, Stereoisomerism, Surfaces and Interfaces, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Lipids, 0104 chemical sciences, chemistry, Pseudorotation, 0210 nano-technology, Cis–trans isomerism
Abstract: International audience; The relative stereochemistry (cis or trans) of a 1,3-disubstituted cyclopentane unit in the middle of tetraether archaeal bipolar lipid analogues was found to have a dramatic influence on their supramolecular self-assembly properties. SAXS studies of two synthetic diastereomeric archaeal lipids bearing two lactosyl polar head groups at opposite ends revealed different lyotropic behaviors. The cis isomer led to L(c)-L(α)-Q(II) transitions whereas the trans isomer retained an L(α) phase from 20 to 100 °C. These main differences originate from the conformational equilibrium (pseudorotation) of 1,3-disubstituted cyclopentanes. Indeed, this pseudorotation exhibits quite similar orientations of the two substituents in a trans isomer whereas several orientations of the two alkyl chains are expected in a cis-1,3-dialkyl cyclopentane, thus authorizing more conformational flexibility in the lipid packing.
Published: 2012

44. Génération de second harmonique accordée en phase dans les cristaux photoniques en semiconducteur III-V à géométrie verticale

Author: Cristelle Mériadec, Petar Vidakovic, Juan Ariel Levenson, Paul Monnier, I. Sagnes, and Yannick Dumeige
Subjects: Physics, Optical materials, General Physics and Astronomy, Second-harmonic generation, Physical chemistry, Nonlinear optics, Phase matching
Abstract: Nous avons observe la generation de second harmonique accordee en phase dans une structure periodique constituee d'Al 30% Ga 70% As et d'AlOx. D'une part l'accord de phase est realise en utilisant le fait que la dispersion du cristal photonique ainsi constitue est suffisante pour compenser la dispersion naturelle du materiau semi-conducteur. D'autre part la localisation du champ electrique a l'interieur de la structure permet une augmentation de l'efficacite de conversion.
Published: 2002

45. Control of peptide nanotube diameter by chemical modifications of an aromatic residue involved in a single close contact

Author: Christophe Tarabout, Franck Artzner, Frédéric Gobeaux, François Besselievre, Emilie Pouget, Cristelle Mériadec, Céline Valéry, Daryl Thomas, Michel Petitjean, Maarten IJsselstijn, Maïté Paternostre, Jean-Marc Verbavatz, Luc Perrin, David-Alexandre Buisson, Jean-Christophe Cintrat, Stéphane Roux, Nicolas Fay, Melinda Ligeti, Bernard Rousseau, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Institut de Biologie et de Technologies de Saclay (IBITECS), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Système membranaires, photobiologie, stress et détoxication (SMPSD), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Interactions cellulaires et moléculaires (ICM), Ipsen-Pharman, Ipsen-Pharma, De Villemeur, Hervé, Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay
Subjects: Models, Molecular, Nanotubes, Peptide, Nanotube, Materials science, Silicon dioxide, Chemical structure, MESH: Somatostatin, Dispersity, MESH: Molecular Structure, Supramolecular chemistry, [SDV.BBM.BP] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, Nanotechnology, 02 engineering and technology, MESH: Microscopy, Electron, 010402 general chemistry, Peptides, Cyclic, 01 natural sciences, MESH: Silicon Dioxide, Nanomaterials, Amino Acids, Aromatic, chemistry.chemical_compound, X-Ray Diffraction, Scattering, Small Angle, [SDV.BBM] Life Sciences [q-bio]/Biochemistry, Molecular Biology, Molecule, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, MESH: Nanotubes, Peptide, MESH: Nanotechnology, MESH: Peptides, Cyclic, MESH: Scattering, Small Angle, Multidisciplinary, Molecular Structure, MESH: X-Ray Diffraction, Chemical modification, Silicon Dioxide, 021001 nanoscience & nanotechnology, 0104 chemical sciences, MESH: Amino Acids, Aromatic, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, Microscopy, Electron, chemistry, Physical Sciences, Somatostatin, 0210 nano-technology, MESH: Models, Molecular
Abstract: International audience; Supramolecular self-assembly is an attractive pathway for bottom-up synthesis of novel nanomaterials. In particular, this approach allows the spontaneous formation of structures of well-defined shapes and monodisperse characteristic sizes. Because nanotechnology mainly relies on size-dependent physical phenomena, the control of monodispersity is required, but the possibility of tuning the size is also essential. For self-assembling systems, shape, size, and monodispersity are mainly settled by the chemical structure of the building block. Attempts to change the size notably by chemical modification usually end up with the loss of self-assembly. Here, we generated a library of 17 peptides forming nanotubes of monodisperse diameter ranging from 10 to 36 nm. A structural model taking into account close contacts explains how a modification of a few Å of a single aromatic residue induces a fourfold increase in nanotube diameter. The application of such a strategy is demonstrated by the formation of silica nanotubes of various diameters.
Published: 2011

46. Protein molecule stratification inside a single curved film: Evidence from X-ray scattering

Author: Stéphane Pezennec, Janine Emile, Cristelle Mériadec, Florian Meneau, Alain Faisant, Franck Artzner, Anne Renault, Estelle Robert, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Science et Technologie du Lait et de l'Oeuf (STLO), Institut National de la Recherche Agronomique (INRA)-AGROCAMPUS OUEST, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Globular protein, [PHYS.PHYS.PHYS-BIO-PH]Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], Analytical chemistry, Synchrotron radiation, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, law.invention, rayon-X, law, Molecule, chemistry.chemical_classification, molécule, propriété physico-chimique, Scattering, X-ray, Protéine, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Synchrotron, 0104 chemical sciences, chemistry, Chemical physics, pression osmotique, Small-angle scattering, 0210 nano-technology, Electronic density
Abstract: International audience; We have studied single curved films stabilized by globular proteins, using small angle scattering. By combining both the use of in-house X-ray and synchrotron radiation, we have measured the structural properties of films (thickness, electronic density) by controlling the physicochemical properties of protein (ovalbumin, pH 7, bulk concentration 10 g L−1). For each experiment, solutions of highly purified protein were freshly prepared to eliminate any problem of aging. The observation of Kiessig fringes shows that the films are thin with an average thickness of 60 nm. Benefiting from the fine angular resolution and the short acquisition time of a synchrotron source, we have highlighted a stratification formation inside the films. This phenomenon suggests protein structural reorganization under confinement, possibly driven by high osmotic pressure.
Published: 2011

47. Ionically Self-Assembled Clustomesogen with Switchable Magnetic/Luminescence Properties Containing [Re6Se8(CN)6]n- (n = 3, 4) Anionic Clusters

Author: Yann Molard, Viorel Cîrcu, Nikolai G. Naumov, Franck Artzner, Cristelle Mériadec, Alexandra Yu. Ledneva, Maria Amela-Cortes, Stéphane Cordier, Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences (SB RAS), Inorganic Chemistry Department, University of Bucharest (UniBuc), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université Rennes 1, Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, General Chemical Engineering, [PHYS.PHYS.PHYS-BIO-PH]Physics [physics]/Physics [physics]/Biological Physics [physics.bio-ph], chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Thermotropic crystal, liquid crystals, Liquid crystal, Lyotropic, hybrid materials, Materials Chemistry, luminescence, Organic chemistry, Inorganic compound, chemistry.chemical_classification, 010405 organic chemistry, General Chemistry, Rhenium, 0104 chemical sciences, Crystallography, chemistry, cluster compounds, Cyclic voltammetry, Luminescence, Hybrid material
Abstract: International audience; Octahedral anionic rhenium clusters are obtained by high-temperature solid-state chemistry synthesis as single crystals or powders within which their charge is counter balanced by alkali cations. The ceramic-like behavior of the solid-state Re6 based inorganic compound limits strongly their use in functional devices. We present herein a facile route to introduce these anionic clusters in a self-organized hybrid organic-inorganic material. By replacing alkali countercations by mesogenic organic ones, polarized optical microscopy (POM), DSC, X-ray, magnetic, fluorescence, and cyclic voltammetry techniques confirm that a lyotropic and thermotropic liquid crystal material, able to switch reversibly from a bright red NIR luminescent form to a magnetic green-colored one, is obtained.
Published: 2011

48. Structure of liquid films of an ordered foam confined in a narrow channel

Author: Alain Moréac, Janine Emile, Patrick Chasle, Franck Artzner, Emmanuel Terriac, Cristelle Mériadec, Jeremy Ohana, Jean-Claude Ameline, Groupe matière condensée et matériaux (GMCM), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Granulaires - Mousses, Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Work (thermodynamics), Thermodynamic equilibrium, Disjoining pressure, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Optics, Pulmonary surfactant, Electrochemistry, Perpendicular, Molecule, General Materials Science, Specular reflection, Composite material, Spectroscopy, Chemistry, business.industry, Surfaces and Interfaces, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, [SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 0210 nano-technology, business, Layer (electronics)
Abstract: International audience; A bamboo foam is the simplest case of an ordered foam confined in a narrow channel. It is made of a regular film distribution, arranged perpendicularly to the channel. Our work consists of studying the structural properties of several films taken in a drained foam. X-ray experiments highlighted the equality of the equilibrium thickness for each film within a foam. The same thickness was found as by measurements of disjoining pressure isotherms, proving as well that films of a bamboo foam behave like isolated ones. The refinement of X-ray data by a simple model of specular reflectivity showed a significant variation of the electronic distribution of the surfactant layer for a common black film forwarding from one equilibrium state to another. A discussion on the organization of the surfactant molecules to the gas/liquid interface and film is proposed.
Published: 2007

49. Monolithic tunable InP-based vertical-cavity surface-emitting laser

Author: Taha Benyattou, Guillaume Saint-Girons, Alexandru Z. Mereuta, Cristelle Mériadec, Antonina Plais, Jean Louis Leclercq, Pierre Viktorovitch, A. Bakouboula, Sophie Bouchoule, Isabelle Sagnes, Philippe Regreny, and Joel Jacquet
Subjects: Optical fiber, Materials science, business.industry, Laser, law.invention, Vertical-cavity surface-emitting laser, Optical pumping, Surface micromachining, chemistry.chemical_compound, Optics, chemistry, law, Wavelength-division multiplexing, Indium phosphide, business, Tunable laser
Abstract: We report on the combination of the well established 1.55 micrometers monolithic VCSEL's concept with the Micro-Opto-Electro- Mechanical System (MOEMS) technological breakthrough in order to develop a novel tunable laser device for wavelength division multiplexing optical systems. Technological issures are presented for fabricating surface micromachined InP-based tunable VCSELs.
Published: 2002

50. Phase-matched frequency doubling at photonic band edges: efficiency scaling as the fifth power of the length

Author: Izo Abram, Yannick Dumeige, Ariel Levenson, Cristelle Mériadec, Isabelle Sagnes, Petar Vidakovic, and Paul Monnier
Subjects: Physics, business.industry, Phase (waves), General Physics and Astronomy, Optical field, Computational physics, Nonlinear system, Optics, Quadratic equation, Fifth power (algebra), Harmonic, Photonics, business, Scaling
Abstract: By exploiting the unique properties of periodic stratified media we demonstrate simultaneously phase matching and enhancement of the optical field under second order nonlinear interaction. This leads to a second harmonic efficiency growth faster than the fifth power of the structure length, far better than the usual quadratic behavior associated with second order nonlinear effects.
Published: 2001

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