Photo-induced wettability of TiO2 film with Au buffer layer

The effect of thickness of Au buffer layer (15-25 nm) between TiO2 film and substrate on the wettability of TiO2 films is reported. TiO2 films grown on Au buffer layer have a higher contact angle of 96-;100° as compared to 47.6o for the film grown without buffer layer. The transition from hydrophobicity to hydrophilicity under UV irradiation occurs within 10 min. for the buffer layered films whereas it is almost 30 min. for the film grown without buffer layer. The enhanced photo induced hydrophilicity is shown to be surface energy driven