Effects of catalytic acid and templating surfactant concentrations on mesostructure of submillimeter-thick mesoporous silica by solvent evaporation synthesis

Submillimeter-thick films of mesoporous silica were synthesized by the solv ent evaporation method using tetraethoxysilane (TEOS) and cetyltrimethylamm onium chloride (CTAC) as the silica source and the templating agent, respec tively. The effects of HCl/TEOS and CTAC/TEOS molar ratios were investigate d. It was revealed that a high CTAC concentration and a low gelation rate a t a low HCl concentration were favorable for the formation of highly ordere d mesostructures, since the mesostructure is governed by the concentration of CTAC at gelation of the solution. The pore diameter increased as the CTA C/TEOS ratio decreased, suggesting the intermediation between a silica wall and a CTAC micelle by a water layer whose thickness increases with the inc rease in the H2O/CTAC ratio. (C) 2001 Elsevier Science B.V. All rights rese rved.