Chem. Mater. 2002, 14, 931-939
931
An in Situ Study of Mesostructured CTAB-Silica Film Formation during Dip Coating Using Time-Resolved SAXS and Interferometry Measurements David Grosso,*,† Florence Babonneau,† Pierre-Antoine Albouy,‡ Heinz Amenitsch,§ A. R. Balkenende,| Aline Brunet-Bruneau,⊥ and Josette Rivory⊥ Chimie de la Matie` re Condense´ e, UPMC-CNRS, 4 place Jussieu, 75005 Paris, France, Laboratoire de Physique des Solides, Universite´ Paris-Sud, 91405 Orsay, France, Institute of Biophysics and X-ray Structure Research, Austrian Academy of Sciences, Steyrergasse 17/VI, 8010 Graz, Austria, Philips Research Laboratories, Prof. Holstlaan 4, 5656 AA Eindhoven, Netherlands, and Laboratoire d'Optique des Solides, UPMC, 4 place Jussieu, 75 252 Paris, France Received October 11, 2001
Silica thin films with ordered porosity can be prepared by dip coating, combining polycondensation of silicate species and organization of amphiphilic mesophases. This paper reports on the preparation of templated films using cetyltrimethylammonium bromide (CTAB) as the surfactant and tetraethoxysilane (TEOS) as the inorganic precursor. Depending on the CTAB/Si molar ratio, films with different porous networkss3D hexagonal (P63/mmc), cubic (Pm3n), and columnar hexagonal (p6m)swere obtained. Identification of the structures was accomplished by coupling two-dimensional X-ray diffraction at grazing incidence and TEM investigations on film cross sections. Other experimental parameters (e.g., deposition rate and composition of the starting sol, including its aging time) appeared also to influence the degree of organization of the final films greatly. To obtain a better understanding of the self-assembly mechanism, the structural formation of the films was followed in real time by in situ SAXS. Because of the very fast self-assembly process (
