Reducing the toughness, rather than the strength, between ice and the surface it covers is key to developing highly icephobic materials, a new study reports. The results hint that if materials are designed with low adhesion toughness, removing ice from them is no longer dependent on how much area the ice covers, as it is with approaches now. Ice accumulation on large surfaces, such as wind-turbine blades, power transmission lines or airplane wings, can cause catastrophic failure. Generally, most contemporary de-icing materials focus on minimizing the adhesion strength between the ice and the surface. However, the amount of force required to detach ice from a surface increases as the area of the iced surface becomes larger. As such, detaching ice from particularly large surfaces can require prohibitively high levels of force, which limits the use of these icephobic coatings and can require costly and environmentally unsafe processes. A countervailing perspective on understanding interfacial ice-adhesion is based upon the toughness, or resistance to lots of little forces, rather than being focused on strength, the resistance of a surface to large forces. Kevin Golovin and colleagues compare traditional strength-limited de-icing with toughness-limited de-icing, in this study. According to the authors, for materials designed with low interfacial toughness (LIT), de-icing is no longer limited as a function of ice coverage. Golovin et al. evaluated the de-icing properties of various plastic and rubber coatings designed with LIT and show a large reduction in the amount of force required to remove ice over large areas. Furthermore, the results demonstrate that PDMS, a commonly used rubber-based icephobic coating, when engineered with low interfacial toughness, was able to cause ice to cleanly and completely detach from large areas merely by the weight of the ice itself.
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Journal
Science