Fine-tuning Cavity Size and Wall Thickness of Silica Hollow Nanoparticles by Templating Polymeric Micelles with Core-Shell-Corona Structure

Hollow silica nanospheres have been successfully prepared by templating the polymeric micelles of poly(styrene-b-2-vinylpyridine-b-ethylene oxide) (PS-PVP-PEO), which shows a core-shell-corona structure in aqueous solutions. In this template, each block has its own function; the PS block (core) works as a template of the void space of hollow silica, the PVP block (shell) acts as a reaction field for the sol-gel reaction of silica precursor, and the PEO block (corona) stabilizes the polymer/silica composite particles. It was found that the diameter of the void space of the hollow silica spheres can be fine-tuned on a several nanometer scale by changing the chain length of the PS block. The wall thickness of the hollow silica is also finetuned by varying the concentration of the silica precursor.