Icephobic/anti-icing potential of superhydrophobic Ti6Al4V surfaces with hierarchical textures

The main purpose of this paper was to investigate the icephobic potential of hierarchical superhydrophobic surfaces, which were prepared by modifying micro-nanostructures (constructed by the combination of sand blasting and hydrothermal treatment) on the surfaces of Ti6Al4V alloy with fluoroalkylsilane (FAS-17). We previously reported that this hierarchical superhydrophobic surface displayed excellent nonwettability with apparent contact angle of 161 degrees and sliding angle of 3 degrees. Thus, the present study focused on the systematic characterizations and analyses of the icephobic potential of the superhydrophobic surfaces around three parameters, including icing-delay time, ice adhesion strength, and contact time of an impacting droplet on cold superhydrophobic surfaces. The results indicated that the icing-delay time of a droplet on the superhydrophobic surface was many times longer than that of a droplet on the smooth Ti6Al4V substrate, and the ice adhesion strength on superhydrophobic surface was greatly reduced, which was attributed to the Cassie wetting state of a droplet on the surface. Additionally, the dynamic droplet impact and rebound assay demonstrated that water droplets always bounced off of the superhydrophobic surfaces before freezing under subzero conditions.