Nano-porous Silica Films Prepared by sol-gel Granular Silica Sol

Homogeneous nanoporous silica films were prepared with colloidal silica sol derived by sol-gel technique of tetraethylorthosilicate(TEOS) catalyzed with NH3?H2O. Dense ammonia enhanced the colloidal solubility of silica and ion intensity; glycerol effectively restrained the growth of silica particles; and PVA adhered to silica particles to form a network, which make it easy to prepare silica films. The pore sizes is 100 nm, the porousity is between 60.50%~7.75%. The refractive indexes of the silica films is between 1.18~1.42 and one layer of the silica films can be adjusted within 3 μm thick.