Photothermally promoted recovery of a superhydrophobic surface with anti-icing and de-icing properties for outdoor applications

Ice accumulation is a persistent problem in high-altitude or low-temperature environments, resulting in the abnormal operation of equipment and even fatal accidents. As such, various strategies for removing (de-icing) and preventing (anti-icing) ice from outdoor equipment have been proposed. In this study, a simple photothermal superhydrophobic coating system was developed by combining hydrophilic/hydrophobic silica agglomerates, a polydimethylsiloxane matrix, and organic photothermal dyes (diaminonaphthyl fluorine, DANF) to prevent the loss of superhydrophobicity during ice accumulation. The coating prepared by the spray-coating method exhibited excellent superhydrophobicity with a uniform water contact angle of similar to 165 degrees and sliding angle of similar to 3.5 degrees over a large area. Sunlight-responsive DANF dye with excellent dispersion stability in common coating resins and higher photothermal conversion efficiency than inorganic photothermal dyes, can increase the surface temperature to similar to 30 degree celsius even in an extreme freezing environment (similar to 20 degree celsius) under a near-infrared laser irradiation (808 nm, similar to 1 sun). Therefore, under solar irradiation, ice freezing on a superhydrophobic surface can be delayed (anti-icing). Even after ice formation, the initial superhydrophobicity can be recovered through the thermal evaporation of water molecules trapped within the micropillars (de-icing). The proposed photothermal superhydrophobic coatings exhibited uniform photoinduced heating over a large area under sunlight, self-cleaning performance, and adaptability to various substrates, indicating their expected applicability to various types of outdoor equipment for preventing abnormal performance due to ice accumulation.