Sintering-Oxidation Method to Prepare Self-Supporting Silica Films

Abstract

In this work, an innovative method of sintering-oxidation has been developed to prepare self-supporting silica films with good flexibility. Polyethylene (PE) film was used as a template, SiC powder and polycarbosilane (PCS) were employed as silicon sources. The surface of the PE films was coated with slurry of SiC powder and hydroxypropyl methylcellulose aqueous solution. After drying, the hexane solution of PCS was sprayed on the slurry. Subsequently, the films were coated with slurry in high-temperature furnace under Ar conditions. After cooling, a white and self-supporting film was prepared. The thickness of the films was 15 μm, and it demonstrated flexibility. The morphology and composition of the film were characterized and the results proved that the films prepared as innovative method described above was pure silica. The formation mechanism and self-supporting mechanism of self-supporting silica films were discussed. The method required no tedious operation or restriction conditions, and is easy and economical. Therefore, the proposed method offers a new way to prepare self-supporting silica films.