Fabrication of convex-shaped polybenzylsilsesquioxane micropatterns by the electrophoretic sol–gel deposition process using indium tin oxide substrates with a hydrophobic-hydrophilic-patterned surface

Polybenzylsilsesquioxane (BnSiO_3/2) particles become a supercooled liquid through a heat treatment above the glass transition temperature (T _g) of the particles. Micropatterns of BnSiO_3/2 thick films with high transparency were obtained by the electrophoretic deposition of the BnSiO_3/2 particles on indium tin oxide (ITO)-coated substrates with a hydrophobic-hydrophilic-patterned surface and subsequent heating above T _g of the particles. It was found that the control of electrophoretic deposition conditions, in which the amounts of the particles deposited on the substrates were changed, led to two types of micropatterning processes of the BnSiO_3/2 thick films. In the first process, the particles were selectively deposited on the hydrophilic areas after the electrophoretic deposition. In the second process, the particles were deposited on the whole area of the ITO-coated substrate with hydrophobic-hydrophilic patterns after the electrophoretic deposition. Due to the difference in wettability of BnSiO_3/2 molten liquids between hydrophobic and hydrophilic surfaces, the molten liquids on the hydrophobic areas, which were obtained by heating above T _g of the particles, migrated toward the hydrophilic areas. In both the processes, convex-shaped BnSiO_3/2 micropatterns with high transparency were fabricated only on the hydrophilic areas after a heat treatment above T _g of the particles.