Improving the Mechanical Durability of Superhydrophobic Coating by Deposition onto a Mesh Structure

Superhydrophobic surfaces (SHSs) require a combination of a nano- or microscale rugosity and a low surface energy. However, SH is easily lost under relatively mild mechanical abrasion. Here, by introducing a mesh layer beneath the SH layer, we develop a method that significantly increases the mechanical durability of a SHS. Using the commercially available Ultra-ever Dry SH coating, we found that hardness, abrasion distance, flexibility and water-jet impact resistance all increase. These increases are attributed to the increased mechanical support offered by the presence of the mesh, which provides dynamic mechanical losses at the temperatures and equivalent frequencies of the applied stresses. The SH of the coating surface on both sliding abrasion and water jet impact, as determined by slide angle (SA), exhibits two steps; the first is associated with the wearing away of the surface nanoparticles, and the second, with the wear of the underlying microstructures. A comparison of the SAs, as a function of abrasion distance, demonstrates that the presence of the mesh can significantly protect the nanoparticles, improving and prolonging SH, thereby extending the number of applications of such coatings. The improved mechanical durability may be attributed to the mesh structure protecting the rugosity, and its ability to absorb the energy from both sliding abrasion and water-jet impact.