Synthesis of polystyrene core/SiO2 shell composite particles and fabrication of SiO2 capsules out of them

Systemic studies on the dependence of the morphology of polystyrene core/SiO₂ shell composite particles on the conditions of their fabrication have been performed. Spherical polystyrene particles synthesized in the presence of a cationic initiator of polymerization were used as cores. SiO₂ shells were formed by modified Stober's method. Exposure of the synthesized composite particles to high temperatures has been shown to cause destruction of their polystyrene core, thereby allowing the formation of mesoporous SiO₂ capsules with a mean pore diameter of ∼3 nm and specific surface area of ∼270 m²/g. Model experiments on loading the SiO₂ capsules with amoxicillin have been carried out. Spectrophotometry in the UV and visible spectral regions has been used to estimate the kinetics of amoxicillin release from the SiO₂ capsules. (paper)