Porous Silica Nanocapsules and Nanospheres: Dynamic Self-Assembly Synthesis and Application in Controlled Release

In this work, porous silica nanocapsules and silica nanospheres have been successfully fabricated by a novel combination of stabilizing condensation and dynamic self-assembly. When ethyl ether was used as a cosolvent, porous silica nanocapsules were obtained. In contrast, when 2-ethoxyethanol was used, silica porous nanospheres were produced. The silica nanostructures were characterized by small-angle X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, and nitrogen adsorption−desorption measurements. They had high Brunauer−Emmett−Teller specific surface areas and large pore volumes. The order of their pore structures increased with an increase of the corresponding cosolvent. In situ encapsulation of organic molecules into silica nanocapsules and their controlled release were further investigated by using pyrene as a typical example. As many dyes, drugs, etc. are organic molecules, the current approaches will doubtlessly open many possibilities toward biological and technological applications.