A simple and low-cost method for the preparation of monodisperse hollow silica spheres

This paper presents a simple and low-cost method to prepare hollow silica spheres. This method is just based on a PVP-involved emulsion polymerization and subsequent sol-gel process. PVP first participated in the polymerization reaction as a stabilizer or surfactant and then played a coupling agent role in the latter process. The polystyrene particles were dissolved subsequently or simultaneously during the sol-gel coating process to form hollow silica spheres. The influence of some parameters, such as the amount of PVP, the amount of NH4OH, and the amount of TEOS on the morphology of the hollow spheres was investigated. The parameters to control over the formation of all hollow spheres were also studied.