One-level microstructure-arrayed hydrophobic surface with low surface adhesion and strong anti-wetting function.

To achieve both a low surface adhesion function and a high anti-wetting function, it is generally necessary to introduce multi-level micro-nano-structures on a surface. However, this will bring the difficulty of preparation technology, and the functions will fail due to the fact that the nanostructures can easily be damaged. In this research, the surface adhesion and anti-wetting properties of several typically one-level microstructure-arrayed hydrophobic surfaces are analyzed with the dynamics theory, including a square pillar-arrayed three-dimensional microstructure, a conical table-arrayed microstructure, and square frustum-arrayed microstructure. It is found that the anti-adhesion performance and anti-wetting property cannot achieve the best performance simultaneously on the one-level microstructure arrayed surfaces. Either the critical pressure of anti-wetting is finite when the surface adhesion is the lowest, or both the anti-adhesion and anti-wetting capacities are finite. However, an interesting phenomenon is found in that the square frustum-arrayed surface can not only achieve an almost infinite anti-wetting capacity when the distance between neighboring microstructures vanishes, but also reach near-zero adhesion when the square frustum reduces to a square pyramid. All the theoretical predictions are further verified by precise numerical simulations. The results of this paper should be helpful for the design of surfaces with low surface adhesion and strong anti-wetting functions in practical engineering.