Preparation and characterization of super-hydrophilic porous TiO2 coating films

In this study, the super-hydrophilic TiO2 coating films are prepared from a lkoxide solutions containing polyethylene glycol (PEG) by the sol-gel metho d on soda lime glass. The effects of PEG addition to the precursor solution on the super-hydrophilic property and microstructure of the resultant coat ing films are studied. The larger the amount and molecular weight of PEG, t he larger are the size and numbers of pores produced in the resultant coati ng films on the decomposition of PEG during heat treatment. The adsorbed hy droxyl content of such porous coating films is found to increase due to the larger size and number of pores in the coating films. However, the transmi ttance of the coating film decreases due to the scattering by the larger si ze and number of pores. The contact angle for water of porous TiO2 coating film decreases with the increase of the adsorbed hydroxyl content, capillar y force and roughness of the resultant coating films. (C) 2001 Elsevier Sci ence B.V. All rights reserved.