Bottom-Up Assembly of a Micron-Flake Armor for Durable Photothermal Superhydrophobic Coatings

Abstract

Superhydrophobic surfaces hold great promise for antifouling, anti-icing, and anticorrosion applications, yet their poor mechanical durability hinders practical adoption. While bioinspired armor-like designs can enhance robustness, current fabrication routes are often complex and not easily scalable. Here, we report a durable superhydrophobic coating with a micron-flake armor structure fabricated via a facile dual-spray process. The bottom layer consists of epoxy resin and micron-sized silica flakes, providing strong substrate adhesion and a flake armor for mechanical wear resistance. The top layer comprising modified silicone resin, nanosilica, and an organic photothermal agent imparts superhydrophobicity and photothermal functionality. The obtained coating exhibits exceptional mechanical wear resistance, maintaining its superhydrophobicity after 44 m of abrasion against 1000 grit sandpaper under a pressure of 9.8 kPa. It also demonstrates excellent stability under water impact, UV irradiation, thermal aging, and acidic/alkaline exposure. Furthermore, the coating achieves 99.9% corrosion inhibition efficiency, delays static freezing by 7.6-fold, delays dynamic freezing by 12-fold, and maintains structural integrity after 50 frosting–defrosting cycles. Owing to its photothermal effect, the coating enables significantly accelerated deicing compared to control groups. This work presents an efficient and scalable strategy for fabricating robust, multifunctional superhydrophobic coatings suitable for industrial environments.