Karine Assaker
University of Lorraine
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Featured researches published by Karine Assaker.
New Journal of Chemistry | 2014
Karine Assaker; Thibault Roques-Carmes; Jaafar Ghanbaja; Marie-José Stébé; Jean-Luc Blin
Herein, we report the preparation and characterization of mesoporous zinc titanate materials. The Zn contents have been estimated by elemental analysis. Samples have been characterized by SAXS, XRD, EDX, nitrogen adsorption–desorption, XPS, Raman and UV spectroscopy. SAXS analysis has shown that the hexagonal array is lost when the zinc content in the materials increases beyond 7 mol%. As proven by XRD and Raman experiments anatase is the predominant phase, however upon zinc addition the crystallinity decreases and the formation of ZnTiO3 is promoted. Finally the photocatalytic activity of the zinc titanate materials has been tested in the photodegradation of methyl orange.
New Journal of Chemistry | 2016
Manon Besançon; Laure Michelin; Ludovic Josien; Loïc Vidal; Karine Assaker; Magali Bonne; Bénédicte Lebeau; Jean-Luc Blin
Two series of TiO2–SiO2 composites have been prepared by post-synthesis impregnation of a TiO2 precursor onto SBA-15 silica matrices and subsequent thermal treatment at 400 °C in air. The influence of the textural properties of the SBA-15 and the TiO2 content was evaluated upon the dispersion of TiO2 and its crystallization in anatase. The morphology of the samples before and after impregnation was observed by electronic microscopy while the textural and structural properties were evaluated by different techniques such as XRD, nitrogen sorption manometry, and Raman spectroscopy. The quantity of crystallized anatase in the composites was determined by XRD quantification using an internal standard. The bandgap energy (Eg) of the composites was evaluated by diffuse reflectance spectroscopy and the results show that Eg decreases as a function of the titania content. The photoactivity of the prepared materials was evaluated by following the degradation of methyl orange (MO) in water under UV irradiation. For the same amount of catalyst, the MO degradation rate in the presence of the composites containing 28 and 44 wt% of crystallized anatase was found to be similar to the one in the presence of commercial fully crystallized anatase.
ACS Applied Materials & Interfaces | 2017
Elvia Anabela Chavez Panduro; Karine Assaker; Thomas Beuvier; Jean-Luc Blin; Marie-José Stébé; Oleg Konovalov; Alain Gibaud
Surfactant templated silica thin films were self-assembled on solid substrates by dip-coating using a partially fluorinated surfactant R8F(EO)9 as the liquid crystal template. The aim was 2-fold: first we checked which composition in the phase diagram was corresponding to a 2D rectangular highly ordered crystalline phase and second we exposed the films to sc-CO2 to foster the removal of the surfactant. The films were characterized by in situ X-ray reflectivity (XRR) and grazing incidence small angle X-ray scattering (GISAXS) under CO2 pressure from 0 to 100 bar at 34 °C. GISAXS patterns reveal the formation of a 2-D rectangular structure at a molar ratio R8F(EO)9/Si equal to 0.1. R8F(EO)9 micelles have a cylindrical shape, which have a core/shell structure ordered in a hexagonal system. The core contains the R8F part and the shell is a mixture of (EO)9 embedded in the silica matrix. We further evidence that the extraction of the template using supercritical carbon dioxide can be successfully achieved. This can be attributed to both the low solubility parameter of the surfactants and the fluorine and ethylene oxide CO2-philic groups. The initial 2D rectangular structure was well preserved after depressurization of the cell and removal of the surfactant. We attribute the very high stability of the rinsed film to the large value of the wall thickness relatively to the small pore size.
Journal of Colloid and Interface Science | 2015
Karine Assaker; Issam Naboulsi; Marie-José Stébé; Mélanie Emo; Jean-Luc Blin
Due to the difference in «mutual phobicity» between fluorocarbon and hydrocarbon chains, mixtures of fluorinated and hydrogenated surfactants are excellent candidates to design bimodal systems having two types of mesopores. In literature, only a few papers deal with these bimodal systems. Here hexagonal liquid crystal mixtures of the polyoxyethylene fluoroalkyl ether [R(F)8(EO)9] and the Pluronic [P123] have been used to template this kind of mesostructure through the liquid crystal mechanism, which is barely considered. After the detailed investigation of the R(F)8(EO)9/P123/water liquid crystal domain, materials have been synthesized and characterized by small angle X-ray scattering, transmission electron microscopy and nitrogen adsorption-desorption analysis. Our results show that this system provides two separate pore sizes in the materials over the mesoporous range. The ratio between the small mesopores and the large ones depends on the proportion between the porogens in the mixture. Nonetheless, we also outline that a minimum quantity of silica is required to recover the two hexagonal networks.
ACS Sustainable Chemistry & Engineering | 2014
Karine Assaker; Bénédicte Lebeau; Claire Marichal; Loïc Vidal; Marie-José Stébé; Jean-Luc Blin
Journal of Physical Chemistry C | 2013
Karine Assaker; Pierrick Durand; Lionel Aranda; Marie-José Stébé; Jean-Luc Blin
Microporous and Mesoporous Materials | 2015
Karine Assaker; Taissire Benamor; Laure Michelin; Bénédicte Lebeau; Claire Marichal; Marie-José Stébé; Jean-Luc Blin
Journal of Alloys and Compounds | 2015
Karine Assaker; Bénédicte Lebeau; Laure Michelin; P. Gaudin; Loı̈c Vidal; Magali Bonne; Jean-Luc Blin
RSC Advances | 2013
Karine Assaker; Bénédicte Lebeau; Claire Marichal; Loı̈c Vidal; Marie-José Stébé; Jean-Luc Blin
Physics Procedia | 2014
Mounir Kassir; Thibault Roques-Carmes; Karine Assaker; Tayssir Hamieh; Angelina Razafitianamaharavo; Joumana Toufaily; Frédéric Villiéras