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 orthosilicate with poly(styrene-co-styrylethyltrimethoxysilane), containing 90 mol% of styrene, in the presence of dibenzoyltartaric acid (DBTA) as a nonsurfactant 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 micropores and mesopores contribute to the porosity of the materials. At high DBTA concentrations (greater than or equal to 45 wt%), mesopores become dominant 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 similar to3-5 nm with relatively narrow size distributions. Polymer chains are covalently bonded to the silica network through the cross-condensation of the alkoxysilyl groups in both the inorganic and polymer precursors. Thermal treatment at 130 degreesC results in appreciable changes in the pore parameters, attributable to polymer chain motions in the hybrid framework.