Hierarchically structured superhydrophobic surfaces with photothermal conversion to avoid icing

Superhydrophobic photothermal materials have gained considerable attention in anti-icing and deicing applications owing to their unique wettability and photothermal conversion capabilities. However, there is a lack of efficient and scalable fabrication methods for crafting superhydrophobic photothermal materials, which significantly hampers the practical applicability of these materials. This paper introduces a scalable strategy that employs maskless electrochemical machining to produce macro/micro/nano hierarchical structures essential for achieving superhydrophobic and photothermal properties. The hierarchical structure is enveloped with numerous interconnected nano pores, contributing not only to the establishment of superhydrophobic properties but also inducing a pronounced "light capture effect". This effect substantially enhances light absorption through multiple reflections, thereby augmenting the photothermal conversion capability. The results show that the modified surface exhibits outstanding superhydrophobicity, featuring a contact angle of approximately 157.6° and a sliding angle of about 1.9° The surface also demonstrates commendable light-capture ability, with an absorption rate of around 92 % within the wavelength range of 200–1600 nm. Moreover, the surface achieves a notable temperature rise of 21.6 °C under one solar irradiation. Crucially, the paper showcases the anti-icing and deicing performance of the fabricated surface. The results underscore the synergistic effect of superhydrophobicity and photothermal conversion, significantly delaying freezing time and efficiently melting ice and frost under light irradiation. In summary, the proposed superhydrophobic photothermal surface exhibits substantial potential and broad impact due to its scalable fabrication characteristics. Its applicability extends to diverse domains such as solar desalination, antibacterial applications, droplet manipulation and oil-water separation.