Patterning ZrO2 films surface: Superhydrophilic and superhydrophobic properties

A photosensitive sol-gel method was used to pattern the surface of ZrO2 film with a groove or a processus mastoideus structure. The surface roughness enhanced by the pattern structure had a strong effect on the ZrO2 film wettability. Compared to an un-patterned ZrO2 film, the patterned film showed a smaller static water contact angle (CA) and exhibited superhydrophilicity. Interestingly, the patterned ZrO2 film did not require the use of UV irradiation to induce the superhydrophilicity and exhibited an excellent anti-fogging behavior. The surface modification with a 1H,1H,2H,2H-perfluorooctyltrichlorosilane (PFOTCS) layer was found to induce the change in the wettability of the patterned ZrO2 films from superhydrophilicity to hydrophobicity/superhydrophobicity. The PFOTCS-modified ZrO2 film patterned with the processus mastoideus surface resulted in the highest CA value of 155° and the sliding angle (SA) value of about 7°, and almost did not change under UV irradiation or after being annealed below 350 °C. The surface patterning by using a photosensitive sol-gel method was proved to be a practical approach to fabricate the ZrO2 film with superhydrophilic/superhydrophobic properties.