A facile process for generating monolithic-structured nano-silica/polystyrene multi-core/shell microspheres by a seeded sol-gel process method.

Monodisperse "monolithic-structured" organic-inorganic composite microspheres were produced by a seeded sol-gel process method. A large number of nano-silica particles were generated and dispersed in the inner domains of the obtained microspheres. Seed particles were prepared by dispersion co-polymerization of styrene and (trimethoxysilyl)propyl 2-methylprop-2-enoate (TMSPM). The seed particles were swollen with an emulsified tetraethoxysilane (TEOS) in 0.25 wt.% sodium dodecylsulfate (SDS) aqueous solutions. Then the sol-gel reaction was conducted with ammonium hydroxide after completion of the swelling process. In contrast to conventional methods, the sol-gel reaction occurred in the inner space of the prepared template particles and monolithic-structured nano-silica and polystyrene organic-inorganic composite microspheres were obtained. The synthetic procedure for composite particles was studied by utilizing transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and thermo-gravimetric analysis (TGA).