The polystyrene (PS) particles functioned by polyvinylpyrrolidone (PVP) were dissolved by the ethanol/NH4OH medium during the SiO2 coating process, and the hollow SiO2 nanospheres were obtained. The influence of the contents of PVP, NH4OH and tetraethoxysilane (TEOS) on the size and morphology of the hollow SiO2 nanospheres was investigated. With increasing the content of PVP, the diameter of the PS particles decreased, and the smaller hollow SiO2 nanospheres were thus obtained. The surface of the hollow SiO2 nanospheres was more and more rough with increasing the content of NH4OH. The thickness of the shell of the hollow SiO2 nanospheres was augmented with increasing the content of TEOS. For the formation of the hollow SiO2 nanospheres, the coating (dissolving) temperature was the most effective factor. The all complete hollow SiO2 nanospheres could be obtained at a coating (dissolving) temperature of 70 ℃.

Key words: SiO2 nanosphere, hollow nanosphere, PVP, NH4OH, TEOS, dissolving temperature