Design and superhydrophobic performance analysis of the rectangular-groove microstructure coated by nanocoatings

Nanocoatings and microstructure fabrication are two key methods to obtain superhydrophobic surfaces. However, the robustness of the nanocoating surfaces is weak and the post-processing of the microstructure surfaces is complicated, and neither of them is ideal for practical useable surfaces. This paper integrates two process technologies and manufactures a rectangular-groove microstructure coated by nanocoatings to obtain a robust superhydrophobic surface. Microscale rectangular groove structures are periodically etched on the surfaces of aluminum alloy by wire electric discharge machine (WEDM), then the nanocoatings were uniformly sprayed on the surfaces of the microstructure. The robustness and superhydrophobicity of the microstructure surfaces with nanocoatings are verified by surface wettability, robustness, weather resistance and chemical durability experiments. Experimental results indicate that microstructure surfaces with nanocoatings are more robust than smooth aluminum alloy surfaces sprayed by nanocoatings. The hydrophobic properties of the nanocoated microstructure surfaces are also much better than that of the uncoated microstructure surfaces.