Synthesis of Mesoporous Silica Spheres by Using Neutral-cationic Surfactant and Semi-batch Growth

A one-step synthesis of mono-dispersed mesoporous silica spheres by using the mixed surfactants CTAB and dodecylamine proceeded with the hydrolysis and condensation of tetraethy-lorthosilicate (TEOS) in a mixture of alcohol, isopropyl alcohol, water, and ammonia as a catalyst. The silica spheres have high specific surface area and can be used as a good substrate in high performance liquid chromatography (HPLC). The size of 0.2~1.5μm and morphology of the silica spheres can be controlled by varying the proportion of surfactant and co-solvent. The prepared silica spheres can be enlarged to the maximum diameter 3μm with a seeded growth method in a semi-batch reacting system. Based on the experiments above, several mechanisms were discussed on the growth process of mesoporous silica spheres in the synthesis.