Published online by Cambridge University Press: 10 February 2011
Monodisperse silica-tin oxide particles of the core-shell type were prepared via a sol-gel process without formation of agglomerates. After synthesis of silica cores the surface was coated with tin oxide by controlled hydrolysis and condensation of tin(IV) tertiary butoxide. Particle properties were characterized by electron microscopy, dynamic light scattering, N2-sorption (BET), zeta potential and X-ray fluorescence analysis. As a consequence of the variable content of tin oxide numerous possible applications arise, for example introducing X-ray opacity in dental filling materials. In order to use such particles as fillers, an additional surface functionalization with 3-methacryloxypropyltrimethoxysilane was created matching the C=C-functional groups of the polymer resins, e.g. ORMOCER*s. Characterization methods such as diffuse reflectance infrared Fourier transform spectroscopy and elemental analysis were used to confirm the surface coverage.