Hierarchical organization of silicate/surfactant system: Biomimetic inorganic materials

Abstract

Mesoporous silica MCM-41 with adjustable and uniformed pore sizes in the range of 1.5 to 10.0 nm, which possesses hexagonal arrangement of uniformly sized channel mesopores, has been the focus of recent investigations. MCM-41 silica possess a wide variety of morphologies. We have found a new way of synthesizing MCM-41 with novel tubular and spherical morphology. Hollow spheres and tubular structures with various topological structures can be obtained in different ranges of water/surfactant/alcohol molar ratio. The sample synthesized with C16TMABr-silicate system with suitable water content leads to tubular morphology. Surfactants with shorter carbon chain length would inhibit the formation of tubular morphology. The sample synthesized with C14TMAB-silicate system with added short chain alcohols leads to hollow spherical morphology with internal pillars. This structure follows from a transformation from the lamellae phase. Detailed studies of mechanism for the formation of these intricate hierarchical orders of the aluminosilicates are discussed. The hierarchical structures are biomimetic and can be understood from the physics of amphiphile organization.