Low–Temperature and Ultrafast Synthesis of Silica–Based Membranes for Gas Separation by Atmospheric–Pressure Plasma–Enhanced CVD

Abstract

we developed a novel technique to fabricate microporous silica membranes by utilizing atmospheric–pressure plasma–enhanced chemical vapor deposition (AP–PECVD). AP–PECVD provided a facile and scalable strategy to synthesize microporous silica membranes under ambient temperature and pressure. The “remote” AP–PECVD, in which the deposition was performed remotely in the downstream of the discharge region, enabled the synthesis of silica membranes even at room temperature. The remote AP–PECVD was further employed for the synthesis of polymer–supported silica membranes, which can potentially minimize the cost of membrane synthesis via the use of inexpensive polymers instead of conventional ceramics to support silica membranes. The “direct” AP–PECVD, where the deposition was performed directly in the discharge region, was also developed to achieve ultrafast synthesis of silica membranes. Direct deposition in the discharge enabled immediate formation of silica thin layer on the order of minutes. The AP–PECVD–derived membranes exhibited outstanding permselectivity comparable to conventional microporous inorganic membranes, providing a nonthermal alternative for the synthesis of silica membranes for molecular separation.