A new preparation method of hierarchical microstructure for wear-resistant superhydrophobic surface

Biomimetic superhydrophobic surfaces are increasingly used on substrate materials in order to improve their performance, such as corrosion resistance, self-cleaning, anti-icing and fluid drag reduction. Scientists have developed many methods to prepare superhydrophobic surfaces, among which wire electrical discharge machining (WEDM) and laser etching are common methods. However, there exist many disadvantages in current preparation methods of superhydrophobic surfaces, such as low mechanical strength, environmental pollution and high cost. Combining the advantages of wire electrical discharge machining (low cost and good wear resistance) and laser etching (small surface texture size), this paper proposes a low-cost and pollution-free hybrid method for preparing wear-resistant superhydrophobic surface with hierarchical microstructure. The hierarchical microstructure includes discharge micro morphology of WEDM and surface texture of laser etching. The WEDM experiments are carried out to analyze the effect of discharge micro morphology on the apparent contact angle. The laser etching experiments are implemented to analyze the influence of process parameters on the contact angle. Heat treatment is adopted to further reduce the surface energy. The experimental results show that the maximum value of surface contact angle (154.1 ± 2°) can be obtained under rough cutting of WEDM, groove width of 100 μm, grid spacing of 300 μm and heat treatment. In addition, after sliding 5000 mm on 600# sandpaper under the pressure of 100g weight, the prepared hierarchical microstructure still maintains superhydrophobic property. The prepared superhydrophobic surfaces show good time durability, mechanical wear resistance, anti-icing and corrosion resistance property.