Toward Exceptional Icephobicity with Chionophile-Inspired Durable Biomimetic Coatings

Liquid-infused polymeric surfaces have demonstrated promising icephobicity. However, the capability to maintain the icephobic performance after material damage has been a challenge, both in terms of conserving a smoother surface and the replenishment of infused liquid. Cetacean skin possesses a microscopically smooth texture in the form of cells lubricated with lipid proteins and consists of structural fibres that ensure durability. Concerning the structure of cetacean skin, glycerol infused fibre-reinforced polyurethane coatings (GIFRP) were proposed. Instead of hosting the lipid proteins, the coatings were infused with glycerol, a known cryoprotectant to induce the supercooling of water, a strategy inspired by wood frogs and red flat dark beetles to prevent freezing. The inclusion of glycerol delayed water droplet freezing duration by 659%, while negligible frost accumulated on the fabricated coatings during anti-icing tests. The reinforcement of fibres was effective and the surface damage was reduced by a factor of 4, compared to the pure polyurethane coatings under erosion impact. The incorporation of fibres has proven to be beneficial for infused-liquid replenishment and the slow-releasing capabilities of GIFRP coatings. Minimised surface deterioration and the continued presence of glycerol on GIFRP coatings demonstrated a small increase in ice adhesion from 0.22 kPa to 0.77 kPa after the erosion tests, one of the lowest values reported in the literature after substantial surface damage. The concept inspired by cetacean skin and the cryoprotective features of chionophiles was instrumental in keeping the ice adhesion under 1 kPa after erosion impact.