Preparation of villus-like PMMA/silica hybrids via surface modification and wet grinding

Abstract

A novel method to prepare inorganic–organic hybrid with villus-like morphology comprising a layer of silica nanoparticles adsorbed on polymethylmethacrylate (PMMA) microsphere was presented in this article. At first, silica nanoparticles were surface treated with vinyltriethoxysilane (VTEOS), and then a wet grinding process with VTEOS as the dispersing agent was utilized to prevent the aggregation of nanoparticles. Zeta-potential measurements confirmed that the surface charge of these milled silica is negative. On the other hand, positively charged PMMA was prepared by adsorption of 2-(methacryloyloxy) ethyl-trimethyl ammonium chloride (METMAC) on as-synthesized PMMA beads. Owing to the electrostatic interaction, the negatively charged silica particles were coated directly on the surface of positively charged PMMA microspheres. The hybrid is fully covered by a layer of silica and the silica content is 18.5%. From our results, it is evident that the villus silica layer adhered on the PMMA bead surfaces and it significantly enhanced the thermal stability of the hybrid microspheres. The characteristics and morphologies of the silica particles, PMMA beads and the resulting PMMA/silica hybrids were investigated by SEM, TEM, FESEM, EDS, FTIR, TGA, and aging analysis.