Preparation Of Hollow Mesoporous Silica Microspheres Based On The Polystyrene Templates

Multistory structured mesoporous silica, especially hollow spherical particles with mesoporous shells(HMS), are of special interest, because they combine the characteristics of both macroporous and mesoporous structures in one single unit. The hollow cavity in these highly engineered particles can act as storage reservoir or a micro-reactor, whereas the mesoporous shell provides controlled release pathways for encapsulated substances or substantial surface area for reactions. As a result, HMS has attracted intense interest in a wide variety of applications, such as catalysis, separation, sensors and drug delivery.In this paper, we selected polystyrene (PS) nanoparticles as templates, hexadecyl trimethyl ammonium bromide(CTAB) as surfactant and the porogen, using tetraethoxysiliane (TEOS) as source of silica, through sol-gel and electrostatic effect mechanism to prepare hollow mesoporous silica microspheres.At the same time, we prepare polystyrene microspheres by the emulsion polymerization. Through the scanning electron microscope(SEM) and transmission electron microscope (TEM), X-ray diffraction, Fourier Transform Infrared Spectroscopy(FTIR) and Thermogravimetric Analysis (TGA), we studied the particle size, morphology, structure of PS and HMS, and analysis the the formation mechanism of the hollow mesoporous silica microspheres.In the preparation of polystyrene template, we have studied the influence of styrene monomer, surfactants and the stirring rate on PS particle size. In the preparation of hollow mesoporous silica, we have studied the influence of template, surfactants and the aqueous ammonia on HMS shell thickness and morphology.