Hierarchical Cauliflower-Like Structural Surfaces for Efficient Anti-Condensation Under Extreme Supercooling Condition

Abstract

Efficient removal of condensation droplets from cooled superhydrophobic surfaces is pivotal for practical applications such as anti-icing, water collection, and condensation heat transfer. However, these surfaces often lose their superhydrophobicity as microdroplets become trapped within their structures during condensation, particularly under high supercooling conditions. Here, a fluorine-free superhydrophobic surface, fabricated via a facile one-step vapor deposition method, is introduced, featuring a hierarchical cauliflower-like structure. This design restricts condensation droplet size to a maximum diameter of ≈50 µm and a coverage rate of ≈16%, markedly enhancing droplet shedding efficiency, due to a hierarchical cauliflower-like structure enhances the larger Laplace force and smaller adhesion. Notably, the surface maintains stable superhydrophobicity even after 720 min of exposure to 100 °C vapor (supercooling of ≈99 °C), surpassing the durability of traditional superhydrophobic surfaces by two orders of magnitude, highlighting its efficacy in anti-condensation under extreme supercooling conditions. Beyond anti-condensation, this design demonstrates enhanced self-cleaning even via condensation droplets or for high-adhesive nanoparticles, eco-friendliness, and demonstrates robust durability, including thermal stability above 500 °C and anti-ultraviolet radiation, thereby broadening its potential for industrial applications in various harsh environments.