Facile Synthesis of Hollow Mesoporous Silica Microspheres via Surface Sol-Gel Process on Functional Polymeric Microsphere Template

A facile and effective route has been developed in this study for synthesis of hollow mesoporous silica microspheres (HMSMs), by employing functional core-shell polymeric polystyrene-co-poly (N-(4-vinylbenzyl)-N, N-diethylamine hydrochloride) (PS-co-PVEAH) microspheres as template and tetraethoxysilane (TEOS) as silica source in the presence of cetyltrimethylammonium bromide. Due to inherent action of Lewis alkaline PVEAH segment on the template surface of the PS-co-PVEAH core-shell microspheres, the sol-gel tetraethyl orthosilicate (TEOS) process was directed exclusively onto the template, avoiding the formation of unwanted and irregular aggregates and therefore well-defined HMSMs were fabricated. The products were characterized by various techniques, including transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and nitrogen adsorption-desorption analysis. Results demonstrated that the HMSMs with size ranging from 256 nm to 148 nm and shell thickness from 9 nm to 16 nm could be synthesized at controlled manner. The obtained HMSMs are anticipated to be good candidates for biomedical applications, such as enzyme immobilization, nano-drug delivery system, protein separation, etc.