Formation and Functionalization of Inorganic-Organic Nanostructured Materials Prepared by Self-Organization of Organoalkoxysilanes.

点击翻译按钮获取中文摘要

Structural control of silica-based hybrids derived from organoalkoxysilanes is a subject of great importance. We developed a new approach to create mesostructured silica-based hybrids by using newly designed siloxane oligomers (C_nH_<2n+1>Si(OSi(OMe)_3)_3, n=8-18) as single precursors. Either well-ordered lamellar phase or slightly distorted 2D hexagonal phase was obtained depending on the alkyl chain lengths in the precursor. The hybrids with a hexagonal structure can be converted to meso-or micro-porous silica upon calcination to remove organic groups, which is the first example of the synthesis of hexagonally ordered porous silica without the use of surfactants as template.We also reported the synthesis of novel layered silica-organic nanostructured materials, consisting of bimolecular layers of long-chain alcohols and thin silica layers, from alkoxytrichlorosilanes (n-C_nH_<2n+1>OSiCl_3, n=12-20). The formation relies on the self-assembly of alkoxysilanetriols (n-C_nH_<2n+1>OSi(OH)_3) generated by the preferential hydrolysis of Si-Cl groups in the precursors. Polycondensation of alkoxysilanetriols was found to proceed in the solid state to form silica networks, being accompanied by the cleavage of the alkoxy groups.