Facile fabrication of fluorine-free photo-thermal super-hydrophobic coating with hierarchical structure for efficient anti-icing and de-icing applications

The inevitable formation and accumulation of ice on exposed surfaces can have adverse effects on the normal performance of equipment and facilities. Here, we developed a novel strategy to fabricate a coating with superhydrophobicity and photothermal effect. Based on the bottom-up approach, metal-organic framework (MOF) Cu-CAT-1 was grown in situ on a copper (Cu) foil to form nano-whiskers and nanowires, and then coated with octadecyltrichlorosilane (OTS) to obtain OTS@MOF@Cu foil. The coated Cu foil exhibited superhydrophobicity with contact angles up to 155.8°. Such a superhydrophobic foil surface also has good chemical stability in harsh solutions. Furthermore, OTS@MOF@Cu foil exhibited stable icing-delay performance (870 s) and extremely low ice adhesion strength (45.7 kPa). Meanwhile, OTS@MOF@Cu foil possessed rapid photothermal de-icing capability (480 s) and frozen ice droplets can spontaneously fall from its tilted surfaces within 360 s. The frost formation process on the surface of OTS@MOF@Cu foil was significantly delayed, lasting up to 15 min even in cold and high humidity conditions. Molecular dynamic (MD) simulation demonstrated that fluorine-free OTS hydrophobic layer significantly slowed down the ice formation process and reduced the adhesion strengths between the ice layer and the contact surface. This study provides a strategy for designing a material with passive anti-icing and active de-icing performances, which could be extended to the practical applications such as aeriation, electrical and transportation under icing weather conditions.