Controllable morphology and pore structure of micron-sized organic-inorganic hybrid silica spheres derived from silsesquioxane

摘要

Mesoporous organic-inorganic hybrid silica with ethylidene bridging group between two silicon atoms was prepared via a sol-gel and hydrothermal synthesis process by using silsesquioxane (1,2-bis(triethoxysilyl) ethane, BTESE) as silicon source and triblock copolymer poly(ethylene glycol)-b-poly(propylene glycol)-b-poly(ethylene glycol) (P123) in combination with dodecyltrimethylammonium bromide (DTAB) as template. Factors that affect the morphology and pore structure of silica particles were investigated in detail by means of scanning electron microscopy, transmission electron microscopy and nitrogen adsorption-desorption. The results show that the sphericity and surface smoothness of organic-inorganic hybrid silica are distinctly enhanced with increasing amount of DTAB and hydrochloric acid. Meanwhile, suitable synthesis time and crystallization temperature are beneficial to the formation of silica spheres with improved sphericity. The organic-inorganic hybrid silica spheres prepared with a DTAB/BTESE molar ratio of 0.8, a HCl/BTESE molar ratio of 6, an aging time of 24 h and a crystallization temperature of 100 A degrees C exhibit a particle size of around 1.7 A mu m, a high surface area of 1063.35 m(2) g(-1) and a narrow pore size distribution centered at 3.12 nm.