Effects of cations on the size and silica shell microstructure of hollow silica nanoparticles prepared using PAA/cation/NH4OH template

Abstract

This paper describes the effect of cations on the size and silica shell microstructure of hollow silica nanoparticles (HSNPs) using polyacrylic acid/cation/ammonium templates in ethanol. The influence of the cations was investigated using four kinds of cations such as sodium, potassium, magnesium, and calcium. The smaller hydrated radius cation could prepare the smaller HSNPs, because the smaller hydrated radius cations could easily interact with the PAAs due to the lower steric hindrance. Moreover, the divalent cations could prepare the smaller HSNPs with the denser silica shell, because the divalent cations could be used as the cross-linker for the PAAs. These results show that the multivalent cation, which has the smaller hydrated radius, can prepare the small HSNPs and the dense silica shell. Therefore, the 10 nm HSNPs with dense silica shell could be prepared using the calcium ion which is a divalent ion with a smaller hydrated radius.