Crystalline Framework Formation in Single-digit Nanometer Scale Silica Nanoparticles of Reverse Mesostructure

Single-digit nanometer scale silica nanoparticles with partially crystalline frameworks were prepared using a reverse mesostructure approach. Crystallization was found on the mesostructure where polycondensation of hydrolyzed silica precursors occurred in confined space of reverse micelles. A formation mechanism of crystalline silica framework was newly proposed under acidic condition at room temperature. Partial frameworks were crystallized in silica nanoparticles of reverse mesostructure that were prepared by evaporation-induced self-assembly under ambient conditions. It was revealed that crystalline domains were sequentially formed in acidic conditions through polycondensation of silica precursors in discretely confined space of outer surfactant micelles.