Superhydrophobicity of micro-structured surfaces on zirconia by nanosecond pulsed laser

This paper presents a systematic approach to improve the hydrophobicity of microstructured surfaces. It includes a contact angle prediction model for microstructures obtained by nanosecond pulsed laser. Combining with the theoretical constraints for stable Cassie-Baxter state this approach can be used to optimize microstructures dimensions for maximising surface hydrophobicity. Laser machining experiments were conducted to evaluate the prediction model. It shows that the proposed systematic approach can accurately predict the contact angle and obtain microstructures dimensions for maximising surface hydrophobicity. The results also indicate that the contact angle increases with the decrease of pitch of the microstructures. Superhydrophobicity with maximum contact angle of 155.7° is obtained, for the first time, on a micro structured surface (P030) of Zirconia with a pitch of 30 μm machined under a laser power at 8W.