Control of Thermal Softening Behavior of Polyphenylsilsesquioxane Particles for Transparent Thick Films by Electrophoretic Deposition

Abstract

Electrophoretically deposited polyphenylsilsesquioxane (PhSiO_3/2) particles were thermally softened to form continuous films, via heat treatment. The onset temperature for thermal sintering of the PhSiO_3/2 particles was successfully controlled from 110 to 270°C by changing the time for their condensation, catalyzed by ammonia, from 0.5 to 120 h. The increased onset temperature mainly resulted from an increase in the molecular weight of the particles as the condensation time increased. The PhSiO_3/2 particles with controlled onset temperatures for thermal sintering were used to obtain highly transparent films, -10μm thick, by electronhoretic deposition and consecutive heat treatment at 200°C.