It is generally recognized that superhydrophobic surfaces in water may be used for corrosion resistance due to the entrapped air in the solid/liquid interface and could find potential applications in the protection of ship hull. For a superhydrophobic surface, as its immersion depth into water increases, the resultant hydrostatic pressure is also increased, and the entrapped air can be squeezed out much more easily. It is therefore predicted that high hydrostatic pressure would cause an unexpected decrease in corrosion resistance for the vessels in deep water (e.g., submarines) because of the unstable entrapped air. In this work, in order to clarify the role of hydrostatic pressure in the corrosion behavior of superhydrophobic surfaces, two typical superhydrophobic surfaces (SHSs) were prepared on bare and oxidized aluminum substrates, respectively, and then were immersed into the NaCl aqueous solutions with different depths of ∼0 cm (hydrostatic pressure ∼0 kPa), 10 cm (1 kPa), and 150 cm (15 kPa). It was found out for the SHSs on the oxidized Al, as the hydrostatic pressure increased, the corrosion behavior became severe. However, for the SHSs on the bare Al, their corrosion behavior was complex due to hydrostatic pressure. It was found that the corrosion resistance under 1 kPa was the highest. Further mechanism analysis revealed that this alleviated corrosion behavior under 1 kPa resulted from suppressing the oxygen diffusion through the liquid and reducing the subsequent corrosion rate as compared with 0 kPa, whereas the relatively low hydrostatic pressure (HP) could stabilize the entrapped air and hence enhance the corrosion resistance, compared with 15 kPa. The present study therefore provided a fundamental understanding for the applications of SHSs to prevent the corrosion, especially for various vessels in deep water.

Solar energy-based renewable energy conversion and storage technologies offer a great promise of combating energy shortage and transitioning to a sustainable society. Efficient collection and transformation play decisive roles in optimizing the harvest of solar energy. Photothermal conversion has emerged as the most efficient solar energy conversion technology, particularly, photothermal coatings could convert light into heat and has triggered a surge of interest in ice removal related applications. Here, we present a comprehensive review of popular documented photothermal conversion materials and the mechanisms of photothermal conversion technologies. Additionally, we pay attention to efficient light-trapping structures for outperformed solar-driven photothermal materials. After that, we investigate the mechanisms of the deicing process. Finally, we discuss the progress of photothermal deicing systems and summarize future challenges in improving their performance. This review serves as a reasonable reference for the classification of photothermal materials and the construction of light-trapping structures, providing valuable insight into the design of photothermal materials for anti-icing applications.

For superhydrophobic surfaces immersed in water, a thin layer of air could be entrapped in the solid/liquid interface.

Superhydrophobic surfaces with an excellent anti-icing performance were prepared on an aluminum substrate using a simple one-step spin coating method. The wettability, morphology, and surface compositions of the prepared surfaces were characterized using the measuring instrument for contact angle and sliding angle, scanning electron microscopy, and Fourier transform infrared spectroscopy, respectively. The contact angle of the as-prepared superhydrophobic surfaces was as high as 165 ± 1.5°, and the sliding angle was less than 5° for a 4 μL pure water droplet, indicating excellent superhydrophobicity and low adhesion. The effects of addition of ZnO powders in different amounts on the morphology and wettability were further analyzed. Moreover, the anti-icing performance of the superhydrophobic surfaces was investigated using a simple lab-made icing monitoring apparatus, and the results are discussed using the one dimensional heat transfer and classical nucleation theory. It was found that the theoretical icing time of the superhydrophobic sample was about five times longer than that of the reference sample whereas for the untreated aluminum, the contact angle was 72 ± 1.5°, which was nearly consistent with the experimental results. The present study demonstrates that the prepared superhydrophobic surface can delay the icing time and decrease the icing temperature, and could be found potential applications in various industries.