Cauliflower-like micro-nano structured superhydrophobic surfaces for durable anti-icing and photothermal de-icing

Ice formation and accretion have a severe negative impact, thus creating the tremendous demand for anti-icing/deicing surfaces. Compared with other techniques, superhydrophobic surfaces possess unique advantages including extremely low affinity to water droplets and reduced ice adhesion strength, whereas their weak durability and failure in cold and moist environments restrict their practical applications. Therefore, photothermal superhydrophobic surfaces possessing high light absorptivity have been proposed, by which ice can be removed by harvesting solar energy as heat eco-friendly and efficiently. However, practical photothermal superhydrophobic surfaces with superior photothermal capability, anti-icing/deicing performance and high durability remain scarce. In this study, a durable cauliflower-like micro-nano structured superhydrophobic surface was produced by combining the ultrafast laser ablation and wet chemical reactions. The hierarchical structures, composed of microcones arrays, in-situ grown cauliflower-like structure and closely bonded PDMS layer, exhibited not only a high absorption rate of 97.3%, but also the high durability in both experimental and natural environment. The temperature raised 48.5 °C under 1 sun illumination for 300 s in ambient conditions. The surface still kept superhydrophobic after several durability tests. The photothermal effect dramatically reduced the ice adhesion strength and deteriorations on the surface during its operation. Under the light intensity of 1 sun for 1 min each cycle, the ice adhesion strength maintained around 10 kPa stably over 40 icing-deicing cycles and the ice layer was melted under 2 min irradiation. Besides, in a three-month long outdoor experiment, the proposed superhydrophobic surface remained its efficient photothermal conversion capacity as well as high durability. Therefore, the cauliflower-like micro-nano structured superhydrophobic surface is one of the most promising methods for anti-icing/deicing applications due to the advantages of superior photothermal capability, long-term durability and adaptability.