Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

A new procedure has been developed, which is based on homogeneous precipitation of organized mesoporous silica from an aqueous solution of sodium metasilicate and a nonionic poly(ethylene oxide) surfactant serving as a structure-directing agent. The decrease in pH, which induces the polycondensation of silica, is achieved by hydrolysis of ethyl acetate. Owing to the complexation of Na⁺ cations by poly(ethylene oxide) segments, assembling of the mesostructure appears to occur under electrostatic control by the S⁰Na⁺I^- pathway, where S⁰ and I^- are surfactant and inorganic species, respectively. As the complexation of Na⁺ cations causes extended conformation of poly(ethylene oxide) segments, the pore size and pore volume of organized mesoporous silica increase in comparison with materials prepared under neutral or acidic conditions. The assembling of particles can be fully separated from their solidification, which results in the formation of highly regular spherical particles of mesoporous silica.

Keywords: Mesoporous SiO₂; Silicates; Nonionic surfactants; Sodium metasilicate; Homogeneous precipitation; Spherical morphology; Heterogeneous catalysis.

References: 19 live references.