Surface modification of silica particles with organoalkoxysilanes through two-step (acid-base) process in aqueous solution

Surface modification of silica particles was achieved by two-step (acid-base) process in an aqueous solution with organoalkoxysilanes, such as methyltrimethoxysilane (MTMS), methyltriethoxysilane (MTES), vinyltrunethoxysilane (VTMS), and vinyltriethoxysilane (VTES). The relative hydrolysis and condensation rates of organoalkoxysilanes; could be elucidated from the kinetic data that were obtained by measuring the mixing time (hydrolysis) and the turbid time (condensation) in this system. Surface-modified silica particles were prepared by two-step process separating the hydrolysis and condensation procedures to easily control the condensation rate. The size of the surface-modified silica particles could be controlled by the ratio of monomer/silica seed. Control of the condensation rate and colloidal interaction could prevent the self-aggregation between primary particles. The size and morphology of the resulting particles were examined by FE-SEM and TEM. The particles were characterized by FTIR and TGA.