Influence of Size of Dispersed Silica Particles on Preparation of Thick Silica Films by Using Electrophoretic Sol–Gel Deposition

Abstract

Abstract Monodispersed silica particles, which ranged from 0.14 to 0.42 μm in diameter, were prepared by the sol–gel method. These particles were first separated from original sols, and dried, heat-treated, and then re-dispersed in a mixture of ethanol, water, and triethoxy(methyl)silane. Thick silica films without micro-cracks were formed by electrophoretic deposition of the particles on a stainless steel sheet in the re-dispersed sols. The weight of the silica films deposited was increased with increasing particle size at a given applied voltage. On the other hand, density of the films was increased with decreasing particle size. When the particle size was 0.32 μm in diameter, crack-free films of ca. 20 μm in thickness were prepared after heat treatment at 800 °C for 1 h.