Silica nanorings on the surfaces of layered silicate

A simple approach to the synthesis of clay-silica nanocomposites is presented. Silica nanorings on the edges of clay sheets were synthesized by using a modified Stöber method. Transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy, and fluorescence spectroscopy were employed to characterize the prepared nanocomposites. TEM results show that the average size of the nanorings increases with the growth of silica. XRD results indicate that the layered structures of clay can be found in the nanocomposite and the growth of silica nanorings expands the d spacing of clay platelets. The mechanism of the formation of the nanorings is discussed. The preparation of polystyrene (PS) brushes on the surfaces of silica nanorings by atom-transfer radical polymerization is also reported. The polymer nanocomposite with negatively charged clay surfaces and hydrophobic polymer brushes on the silica nanorings can be used in Pickering emulsions, and PS colloidal particles with clay-silica on the surfaces were prepared.