Anion-exchange-driven disassembly of a SiO2/CTAB composite mesophase: the formation of hollow mesoporous silica spheres.

Silica-based surfactant/inorganic composite mesophases have been extremely studied. In this work, we developed a mild method to realize the room-temperature disassembly of a SiO(2)/cetyltrimethylammonium bromide (CTAB) mesophase in a neutral medium. Using KMnO(4) as a typical etching agent, SiO(2)/CTAB mesophase spheres were partially disassembled into normal or rattle-type hollow structures. The disassembly of the SiO(2)/CTAB spheres was supposed to be driven by anion exchange between permanganate and silicate ions. This unique method makes possible the selective etching of a SiO(2)/CTAB mesophase over a SiO(2) phase.