DEPOSITION PROCESS AND PROPERTY OF SILICA FILMS CONTAINING ORGANIC GROUPS FROM AQUEOUS-SOLUTION OF ALKOXIDES

Silica thin films containing organic groups were directly deposited fr om aqueous solutions of silicon alkoxides. Effects of functional, grou ps of the alkoxides and the deposition conditions on the preparation o f the films were investigated in order to clarify the deposition proce ss. Silica films containing methyl and phenyl groups were deposited fr om aqueous solutions of methyl- and phenyltrialkoxysilanes, respective ly, in the pH region lower than 3 or higher than 6. The composition an d the property of the deposited films were influenced by pH and the te mperature of the solutions and the starting materials. The adhesion of the deposited films on hydrophobic substrates was lower than that on hydrophilic ones, although the films were formed on both surfaces. The refractive index of the methyl-containing films, ca. 1.44, decreased with removal of methyl groups by heating up to 500 degrees C.