Stone rubbing–inspired biomimetic multi–scale surface with highly robust superhydrophobicity

It has been widely recognized that the key issue limiting practical applications of superhydrophobic surfaces is the insufficient robustness. Combining robust microstructure and superhydrophobic material is an effective way to achieve robust superhydrophobicity. Mechanical robustness and superhydrophobicity are usually realized individually and sometimes cannot appear simultaneously in some local regions of the surface. Here, a stone rubbing–inspired strategy was explored to create biomimetic multi–scale surface (BMS) with highly robust superhydrophobicity. The strategy fused mechanical robustness and superhydrophobicity for the entire surface to be created, rather than realizing them individually. BMS was constructed on the substrate of cemented carbide considering the structure features of both honeycomb and lotus leaf. Biomimetic hexagonal recessed microstructures, biomimetic protrusion microstructures and biomimetic micro–/nano–structures layer were superimposed together to form BMS. The resulting BMS with stand protrusion microstructures (BMSS) and tilted protrusion microstructures (BMST) were analyzed to reveal the influences induced by the side length lm (260 μm to 350 μm) of the hexagon and the laser angle φ (110° to 140°). It was found that the strategy effectively synthesized the advantages and circumvented the disadvantages of the microstructures and the micro–/nano–structures layer. BMSS and BMST separately well maintained low-adhesive and high-adhesive superhydrophobicity under sandpaper abrasion, Taber abrasion, knife-scratch and tape peel. The abraded BMS was able to perform self-cleaning, resist slurry impact and manipulate water droplets. The proposed strategy can be extended to various combinations of materials with high wear resistance or low surface energy.