Synthesis of hollow SiO₂/polystyrene composite microspheres by Pickering emulsion polymerization

Nano-SiO₂, which were synthetized via improved Stöber method, were endowed with amphiphilic surface by means of surface modification with long chain alkyl silane coupling agent. Stable Pickering emulsion was fabricated using this amphipathic nano-SiO₂ particles as stabilizer. The SiO₂/polystyrene composite microspheres with hollow structure were successfully synthetized through adjusting the ratio between styrene monomer and n-octane. The products were characterized by fourier transformation infrared spectrum (FTIR), gel permeation chromatography coupled with a multi angle laser light scattering photometer (GPC-MALLS), thermogravimetic analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). A possible mechanism for the formation of the hollow composites by Pickering emulsion polymerization was proposed at last.