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

At low concentrations of cetyltrimethylammonium bromide, ail silica-based mesoporous materials with hexagonal phase have been synthesized via interactions between sell-assembled surfactant molecule aggregates and anionic silicate polymers. The resulting materials are characterized by XRD, FT-IR, solid stale Si-29 MAS NMR, thermal analysis and N-2 adsorption-desorption measurements. After soluble ions are removed, the interactors between surfactant micelles and silicate polymers are reorganized and then form mesostructures. The hexagonal framework is consistent with amorphous silica gel. The structures of materials depend on the synthesis conditions. Hydrothermal process improves the interactions between molecules and increases the degree of framework silicon atom polymerization. The surface area and the mesopore volume of the material prepared at 100 degrees C increase by 87% and 71%, respectively, compared with those obtained at room temperature.