title: Nonionic Fluorinated Surfactant Removal from Mesoporous Film Using sc-CO2.
abstract: Surfactant templated silica thin films were self-assembled on solid substrates by dip-coating using a partially fluorinated surfactant R8F(EO)9as 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-CO2to 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 CO2pressure 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)9micelles have a cylindrical shape, which have a core/shell structure ordered in a hexagonal system. The core contains the R8Fpart and the shell is a mixture of (EO)9embedded 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.
authors.affiliation: Deparment of Physics, Norwegian University of Science and Technology ,Høgskoleringen 5, 7491 Trondheim, Norway.|IMMM, UMR CNRS 6087, Université du Maine , Le Mans 72085 cedex 09, France.|ESRF , 6 Jules Horowitz, Grenoble 38000 cedex, France.
authors.forename: Elvia A
authors.initials: EA
authors.lastname: Chavez Panduro
authors.affiliation: Université de Lorraine/CNRS, SRSMC, UMR7565 , Vandoeuvre-lès-Nancy F-54506 cedex, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Assaker
authors.affiliation: IMMM, UMR CNRS 6087, Université du Maine , Le Mans 72085 cedex 09, France.
authors.forename: Thomas
authors.initials: T
authors.lastname: Beuvier
authors.affiliation: Université de Lorraine/CNRS, SRSMC, UMR7565 , Vandoeuvre-lès-Nancy F-54506 cedex, France.
authors.forename: Jean-Luc
authors.identifier: http://orcid.org/0000-0002-0947-2552
authors.initials: JL
authors.lastname: Blin
authors.affiliation: Université de Lorraine/CNRS, SRSMC, UMR7565 , Vandoeuvre-lès-Nancy F-54506 cedex, France.
authors.forename: Marie-José
authors.initials: MJ
authors.lastname: Stébé
authors.affiliation: ESRF , 6 Jules Horowitz, Grenoble 38000 cedex, France.
authors.forename: Oleg
authors.initials: O
authors.lastname: Konovalov
authors.affiliation: IMMM, UMR CNRS 6087, Université du Maine , Le Mans 72085 cedex 09, France.
authors.forename: Alain
authors.identifier: http://orcid.org/0000-0002-7777-6427
authors.initials: A
authors.lastname: Gibaud
keywords: GISAXS; XRR; nonionic fluorinated surfactant thin film; sc-CO2; silica mesoporous