Mixed surfactant templating route for mesoporous silica

Mesoporous silica SBA-3 was synthesized by using mixtures of cationic surfactant cetyltrimethylammonium bromide (CTAB), and six nonionic surfactants containing polyoxyethylene as template. The results show, that either by changing the ratio of nonionic to cationic surfactant in the mixture, or by increasing the non-polar chain length of the nonionic surfactants, the pore size can be controlled and the mesoporous silica with larger pore size than that synthesized by using CTAB alone as template can be obtained. The shortcoming of less ordered pore array in the mesoporous silica synthesized by using nonionic surfactant alone as template can also be overcome. Mesoporous silica MCM-48 was also synthesized by using CTAB-CnNH2 (n = 8,10,12,14) as template in basic medium. It is revealed that the transition from cubic to lamellar structure takes place with increasing chain length of alkylamine. The effect of non-polar and polar organic additives on d-spacing of silica SBA-3 for CTAB template system was investigated. (C) 2001 Elsevier Science B.V. All rights reserved.