Effects of temperature on the structure of mesoporous silica materials templated with cationic surfactants in a nonhydrothermal short-term synthesis route

Abstract

This paper reports the influence of synthesis temperature on the structure of mesoporous silica materials templated with ionic surfactant. The results obtained allow for the prediction of optimal temperature value to be used in nonhydrothermal short-term synthesis. The model materials were mesoporous silicates of MCM-41 type. The samples were prepared under alkaline conditions using tetraethyl orthosilicate as a silica source and cetyltrimethylammonium bromide or octadecyltrimethylammonium bromide as templates. An increase in synthesis temperature led to a rougher surface and decrease in the long-range ordering of the materials obtained, while a slight temperature decrease produced additional porosity. The reasons for these structural disturbances were briefly explained. The best material structure was obtained by synthesis at a temperature slightly higher than the Krafft temperature of surfactant of the porosity template.