Synthesis of mesoporous silica by using anionic surfactant

Abstract

Abstract The first synthesis of mesoporous silica via the S−I+ (S−: anionic surfactant and I+: cationic silicates) pathway using an anionic surfactant has been demonstrated. The S−I+ pathway is promoted by utilization of 3-aminopropyltriethoxysilane, an organoalkoxysilane containing cationic functional group, which can interact with the anionic head group. A variety of commercial and well-known anionic surfactants such as sodium dodecylbenzenesulfonate, sodium dodecylsulfate and lauric acid sodium salt can be used for the formation of a silica-micelle composite. In this novel pathway, the electrostatic interaction between the positively charged amino groups in 3-aminopropyltriethoxysilane and the negatively charged sulfate head groups in sodium dodecyl sulfate is a driving force for the self-assembly of the silica-micelle composite. Extraction of the surfactant by acid treatment led to the inorganic-organic hybrid mesoporous silica containing a large amount of aminopropyl groups. Calcination of the silica-micelle composite at 823 K led to the removal of the aminopropyl moieties as well as the surfactant used.