Preparation and Characterization of Silica Hollow Nanospheres

Hollow SiO2 nanospheres were prepared in ethanol/NH3·H2O medium by precipita-ting SiO2 on polystyrene(PS) particulates functionalized by polyvinylpyrrolidone(PVP).The main factors influencing the formation of hollow SiO2 nanospheres were investigated.Moreover,possible mechanism for the formation of hollow SiO2 nanospheres was explored.It was found that at a certain reaction time,hollow SiO2 nanospheres were easily obtained at a temperature of 70 ℃ and NH3·H2O dosage of 0.6 mL.Besides,it was feasible to manipulate the thickness of the encapsulating shell by adjusting the content of tetraethyl orthosilicate(TEOS).