Design and Characterization of Interconnected, Microporous Hybrid Thin Films by a Sol−Gel Process

Abstract

Interconnected, microporous thin films have been prepared by formation of organic−inorganic hybrid materials via a sol−gel process. The spin-coating solution was obtained by hydrolyzing tetramethoxysilane (TMOS) with different portions of methyltrimethoxysilane (MTMS) under acidic catalyst. The organo−silicon groups incorporated into the structure reduced the extent of cross-linking of the silicate network during the curing process, and promoted the formation of a porous structure. The type I sorption isotherms and diffusion-controlled adsorption kinetic studies on the films indicated that the hybrid materials were microporous and that the interconnected pores had an effective pore size close to the diameter of nitrogen. The microporosity and microstructures of the hybrid materials were also qualitatively supported by using TEM, 29Si MAS/NMR, and FTIR spectroscopy.