Photoinduced amphiphilic property of InNbO4 thin film

An InNbO4 thin film was prepared by a sol-gel method. The photoinduced amphiphilic (hydrophilic and lipophilic) property on the film was determined from the changes in contact angles for water and diiodomethane (CH2I2) under light (lambda > 300 nm) irradiation. Before light irradiation, the contact angles for water and diiodomethane were approximately 50 degrees and 40 degrees, respectively. Subsequently, light irradiation induced the contact angles to decrease. The critical contact angles for water and diiodomethane were approximately 0 degrees and 15 degrees, respectively, suggesting that this film possesses the photoinduced superhydrophilic and amphiphilic properties. This is the first report of a complex oxide with a photoinduced amphiphilicity. In the photoinduced amphiphilic conversion process, it was also found that both the total gas-solid surface free energy and the gas-solid surface free energy of the polar component increased.