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 (≥45 wt%), mesopores become dominant and the hybrid materials exhibit high surface area of ∼800 m2 g−1, pore volume of ∼0.6 cm3 g−1 and pore diameters of ∼3–5 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 °C results in appreciable changes in the pore parameters, attributable to polymer chain motions in the hybrid framework.