Formation of Highly Robust Superhydrophobic Nanocomposite Coatings via Dual Spraying Technique

The development of materials that repel water, known as superhydrophobic materials, has been hindered by their vulnerability to mechanical abrasion. This issue is particularly pronounced for superhydrophobic nanocomposite coatings fabricated using a simple blend of resin and nanoparticles (NPs) through uncomplicated methods such as spraying or brushing, where an excessive amount of NPs can deteriorate the mechanical property. Moreover, the limitation of thickness puts forward a request for a high retention rate of the coatings. In response to these challenges, this study presents an innovative approach aimed at enhancing the robustness of superhydrophobic nanocomposite coatings through the utilization of a straightforward dual spraying technique. The results demonstrate that the particles with hierarchical micro/nanostructures fabricated by the primary spraying process provide abundant roughness feedstocks for the secondary‐sprayed coatings, in which superhydrophobicity properties can be achieved with less NP content. Additionally, the mechanical durability of the coatings can be reinforced by the addition of appropriate amounts of aluminum oxide (Al₂O₃) NPs and the continuous‐distributed particles fabricated by the primary‐spraying process, exhibiting a longer abrasion distance and a higher retention rate. Also, the prepared sample shows comprehensive robustness in adhesion, abrasion, and dynamic impact tests. By offering insights into material selection and process optimization, this study paves the way for creating resilient superhydrophobic coatings using a streamlined and convenient approach.