(429b) Relationships Between Water Wettability and Ice Adhesion

Ice formation and accretion may hinder the operation of, for example, airplanes, power lines, windmills, ships, and telecommunications equipment. Yet despite the pervasiveness of the icing problem, the fundamentals of ice adhesion have received relatively little attention in the literature, and it is not widely understood which attributes must be tuned to design icephobic surfaces. Here we probe the relationships between advancing/receding water contact angles and the strength of ice adhesion to a range of test coatings. Contact angles are measured using a commercial goniometer while the shear strengths of ice adhesion are evaluated with a home-built laboratory-scale apparatus. The coatings investigated consist of commercially available homopolymers blended with fluorodecyl polyhedral oligomeric silsesquioxane (FluoroPOSS), a low surface energy additive known to enhance liquid repellency. These test surfaces allow us to explore a broad range of water wettabilities and we find that high receding water contact angles correlate strongly with reduced ice adhesion. We believe these results allow us to estimate the minimum strength of ice adhesion that is attainable on smooth surfaces using known low surface energy coatings. Current investigations are focused on incorporating surface texture (including reentrant topographical features) into the design of icephobic surfaces.