Effects of twin methyl groups insertion on the structure of templated mesoporous silica materials

Abstract

In this paper, the effects of dimethyldiethoxysilane (DMDES) addition on the sol-gel process in preparation of mesoporous hybrid silicates containing twin methyl groups, were investigated. The materials were synthesized using tetraethoxysilane (TEOS) as silica source and DMDES as methyl groups precursor. All samples were prepared at low temperature in alkaline conditions using cetyltrimethylammonium bromide (CTAB) as a template. Obtained materials were characterized applying nitrogen adsorption/desorption, X-ray diffraction, HR TEM, FTIR, 29Si MAS NMR and Raman spectroscopy methods. The influence of aging time (from 5 min to 24 h) on the structure of samples containing 12% (mol/mol) of organic modifier was examined. Duration of synthesis significantly affected the material structure. The effect of added organosilicate amount (12%, 25% and 38%) on morphology and structure properties of prepared samples was also studied. The dimethylsilyl groups were successfully incorporated in wide range in the silica surface using presented short time sol-gel method.