Preparation of organic/inorganic composites by deposition of silica onto shell layers of polystyrene (core)/poly[2-( N, N-dimethylamino)ethyl methacrylate] (shell) particles

Abstract

Organic/inorganic composites were prepared by catalytic hydrolysis and subsequent condensation of tetraethoxysilane (TEOS) in a shell layer of core–shell polymer particles. First, core–shell particles were prepared by emulsifier-free emulsion polymerization of styrene (St) with 2-chloropropionyloxyethyl methacrylate (CPEM) using potassium persulfate as an initiator, followed by surface-initiated activator generated electron transfer–atom transfer radical polymerization (AGET–ATRP) of 2-( N, N-dimethylamino)ethyl methacrylate (DMAEMA). Dynamic light scattering revealed that hydrodynamic diameter of the particle increased from 482 to 931 nm after AGET–ATRP of DMAEMA. The amount of grafted DMAEMA was determined to be ca. 10 mol% with respect to (wrt) St by 1H NMR. Second, the composite particles were prepared by adding TEOS into a water/methanol dispersion of the P(St-CPEM)- g-P(DMAEMA). The P(St-CPEM)- g-P(DMAEMA)–SiO 2 composite particles containing ca. 50 wt.% of silica wrt the total weight were obtained. Hollow silica shell particles were also obtained by extraction of polymer components from the composites with tetrahydrofuran.