Effect of Anodizing Process and Modification on Hydrophobicity of TiO₂ Nanotube Array Film

The TiO₂ nanotube array film was prepared on the titanium sheet surface by anodizing method, and the microstructure of the film prepared at different anodizing voltages (15-25 V) and times (0.5-2 h)was studied. Then the film was modified by stearic acid. The wetting performance of the film before and after modification was analyzed. The results show that the average diameter and tube spacing of TiO₂ nanotube increased with increasing anodizing voltage, but did not changed obviously with the anodizing time. The surface structure uniformity was affected by the anodizing time, and the structure uniformity after anodizing for 2 h was realtively good. The surface of the film before modification was hydrophilic, and after modification was hydrophobic. The more hydrophilic the film before modification, the more hydrophobic after modification. The anodizing time had a greater effect on the water contact angle of the modified film. The films prepared by anodizing at different voltages for 2 h were all superhydrophobic after modification. The average water contact angle of the modified film prepared at 20 V/2 h was the highest, and the value was 159.7°.