The synthesis of hollow silica nanostructures by co-assembly of silica and surfactants

Abstract

The research focused on the synthesis of hollow silica nanostructures by co-assembly of silica and surfactants. The major projects include understanding the cylinder-to-vesicle phase transition of mesoporous silica, the application in encapsulation of hydrophobic dyes in silica vesicles and fabrication of core-shell nanostructures with mesoporous silica shells, exploration and application of the dissolution and re-growth process in the formation of silica nanostructures, studying the formation mechanism of helical mesoporous silica, and researching on the stability of silica and doping cationic species into silica nanostructures. As summarized in a phase diagram, the outcome of the surfactant-silica co-assembly can be rationally controlled by the concerted effects of the ingredients. The cylinder-to-vesicle transition reveals basic principles underlying the phase control. Such understanding permits insights in the unique behaviors of surfactant-silica co-assembly and grants readily control of the phases of mesoporous silica. On the basis of the above understanding, core-shell nanostructures with mesoporous silica shells were created by simply depositing the clumps of start materials as shells on the nanoparticle surface. We have also developed a new method to load hydrophobic dyes into silica nanostructures. By doping functional molecules in the clumps of start materials, we have synthesized different new functional silica nanostructures.