Synthesis of polystyrene-silica hybrid mesoporous materials via the nonsurfactant-templated sol-gel process

The first synthesis of polymer-silica hybrid mesoporous materials has been achieved via the acid-catalyzed sol-gel reactions of tetraethyl orthosilica te with poly(styrene-co-styrylethyltrimethoxysilane), containing 90 mol% of styrene, in the presence of dibenzoyltartaric acid (DBTA) as a nonsurfacta nt template or pore-forming agent, followed by extraction with EtOH-H2O (2: 1 v/v) to remove the DBTA molecules. At low DBTA concentrations, both micro pores and mesopores contribute to the porosity of the materials. At high DB TA concentrations (greater than or equal to 45 wt%), mesopores become domin ant and the hybrid materials exhibit high surface area of similar to 800 m( 2) g(-1), pore volume of similar to0.6 cm(3) g(-1) and pore diameters of si milar to3-5 nm with relatively narrow size distributions. Polymer chains ar e covalently bonded to the silica network through the cross-condensation of the alkoxysilyl groups in both the inorganic and polymer precursors. Therm al treatment at 130 degreesC results in appreciable changes in the pore par ameters, attributable to polymer chain motions in the hybrid framework.