Preparation of Superhydrophobic Coatings with Drag Reduction and Anti-icing Properties via a Simple Spraying Method

Underwater drag and icing pose significant challenges in navigation bodies such as ship navigation. Despite the importance of mitigating these challenges, functional surfaces that can integrate both anti-icing and drag-reduction properties remain scarce. In this work, we fabricate a superhydrophobic coating by spraying modified TiO2 nanoparticles on Al substrates, which can reduce drag while delaying icing. The superhydrophobic coating demonstrated excellent drag reduction performance, with a drag reduction rate of 39.8%. At the same time, under a low-temperature environment of 15 °C, the superhydrophobic coating delayed the ice formation rate by 6 times compared to the substrate. This is because the rough micronano structure of the superhydrophobic coating can trap air. The trapped air not only generates gas–liquid interfaces that replace solid–liquid interfaces, inducing slip flow and thereby reducing drag, but also reduces the thermal exchange between the droplets and the substrate and delays the nucleation of ice, thereby achieving delayed freezing. Therefore, this study proposes a novel method for large-area preparation of functional surfaces with drag reduction capabilities and provides an anti-icing capability.