Composite Silica Particles Using A Mixture of Organosilane Monomers: Effect of Molar Ratio of Monomers

초록

Composite silica particles were synthesized by two-step (acid-base) process in an aqueous solution with a mixture of organoalkoxysilane monomers. The two-step process separates the hydrolysis and condensation procedures to easily control condensation rate. In this study, as silane monomers were used phenyltrimethoxysilane (PTMS), vinyltrimethoxysilane (VTMS), methyltrimethoxysilane (MTMS), and tetraethyl orthosilicate (TEOS). The reaction was performed in the variation of reaction temperature, hydrolysis time, and the molar ratio of silane monomers. The physical properties of resultant particles in combination of silane monomers were investigated with the change in the molar ratio of monomers. In particular, the hollow particles were obtained when the molar ratio of PTMS to VTMS was higher than 8.0 in the case of PTMS-VTMS combination. The hollow size of the resultant particles increased with increasing the molar ratio of PTMS to VTMS. The size and morphology of the resulting particles were analyzed by field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The change of zeta potential in the surface of particles in variation of the molar ratio of silane monomers was determined by zeta potential analyzer. In addition, the characterization of the obtained particles was preformed by infrared spectroscopic analysis (IR), solid-state nuclear magnetic resonance spectroscopy (NMR) and thermogravimetric analysis (TGA).