Dip-coating of TiO2 films using a sol derived from Ti(O-i-Pr)4-diethanolamine-H2O-i-PrOH system

Abstract

Diethanolamine (DEA) can suppress the precipitation of oxides from the alcoholic titanium isopropoxide solution in its hydrolysis so that much water can be added to the Ti(O-i-Pr)4-diethanolamine-i-propanol the solution to give a clear solution. Addition of excess water converted the solution to the gel. The conditions for the formation of the clear solution and gel are examined. Uniform transparent TiO2 films can be prepared by dip-coating with the clear solution. The limit of the thickness of uniform films was 200 to 240 nm. Films thicker than 1 μm can be prepared by repeating the coating cycle. These films were well densified. Diethanolamine has some positive effect on the densification of the TiO2 crystals. © 1988 Chapman and Hall Ltd.