One-Step Preparation of Porous Silica Spheres from Sodium Silicate Using Triblock Copolymer Templating

Mesoporous and microporous monodispersed silica spheres have been prepared using a simple one-step synthetic procedure from an aqueous reaction mixture consisting of a commercial sodium silicate solution, various Pluronic triblock copolymers, and HCl or HNO3. The formation of porous silica spheres 130-225 m in diameter was observed over a moderately wide range of reaction conditions. The pore structures of the resultant spheres lacked any long-range order, although they did exhibit outer textural uniformity. We concluded that the well-defined spherical morphology and pore sizes were the result of a combined effect of the EO/(EO + PO) block ratio and molecular weight of the Pluronics and the counteranions of the acid source.