Morphology Control of Mesoporous Silica Particles

Abstract

We demonstrate morphology dependence of mesoporous silica synthesized in acidic condition via the control of silica hydrolysis and condensation at 4 °C under quiescent acidic condition, and without using any organic cosolvents. Tetramethyl orthosilicates (TMOS) is used as a silica source and cetyltrimethylammonium chloride (CTAC) as the structure directing agent (SDA). Straight fibers of different aspect ratio with pore channels aligned parallel to the fiber axis are synthesized by varying TMOS from the sols of molar compositions 0.17−0.32TMOS:0.22CTAC:9HCl:100H2O. Curved morphologies such as discoids and spheres are prepared by controlling acidity in the sols of molar compositions 0.17TMOS:0.22CTAC:14−16HCl:100H2O. The mesoporous silica particles show BET surface area of 1100−1400 cm3/g, and the mesopore diameter and mesopore volume are in the range of 2.2−2.6 nm and 0.6−0.8 cm3/g, respectively.