Core shell silica-silicon hybrid nanoparticles: synthesis and characterization

摘要

Silica-silicon hybrid nanoparticles completely soluble in hydrocarbon were prepared by copolymerization of tetraethoxysilane (TEOS) and alkylethoxysilanes like methyltriethoxysilane (MTEOS), dimethyldiethoxysilane (DMDEOS) and dimethoxydiphenylsilane (DMODPS) by using the sol-gel process catalyzed by ammonium hydroxide in ethanol and methanol. Control of surface chemical structure and solubility was achieved by introducing trimethylchlorosilane (TMCS) as polymerization terminator. Nanoparticles with diameter in the range of 10 to 52 nm were obtained. The structure and thermal stability of the nanoparticles were highly dependent on the reaction condition. Higher conversion of hydrocarbon soluble silica-silicon nanoparticles were attained using water:Si molar ratio close to 9. The hexane soluble nanoparticles present hydroxyl and methyl groups on the surface. Wide angle X-ray diffraction and ~(29)Si solid state NMR show evidences that these silica-silicon hybrids presents a core-shell structure with a core constituted by SiO_2 and a shell formed by methyl or phenyl siloxane. The material can be applied to prepare different types of silica-silicon hybrid membranes.