Formation at low surfactant concentrations and characterization of mesoporous MCM-41

Abstract

At low concentrations of cetyltrimethylammonium bromide, all silica-based mesoporous materials with hexagonal phase have been synthesized via interactions between self-assembled surfactant molecule aggregates and anionic silicate polymers. The resulting materials are characterized by XRD, FT-IR, solid state29Si MAS NMR, ther-mal analysis and N2 adsorption-desorption measurements. After soluble ions are removed, the interactors between sur-factant micelles and silicate polymers are reorganized and then form mesostructures. The hexagonal framework is con-sistent with amorphous silica gel. The structures of materials depend on the synthesis conditions. Hydrothermal pro-cess improves the interact~ons between molecules and increases the degree of framework silicon atom polymerization. The surface area and the mesopore volume of the material prepared at l000C increase by 87% and 71 %, respectively, compared with those obtained at room temperature.