Enhanced stability and durability of Cassie-Baxter state in aluminum-based superhydrophobic surfaces fabricated via nanosecond laser ablation

The stability of the Cassie-Baxter (CB) state plays a crucial role in the application of metallic superhydrophobic surfaces, especially in low-temperature and high-humidity environments. Despite the extensive research on superhydrophobic properties achieved through various micro/nanostructures, the instability of the CB state remains a significant obstacle to commercializing these surfaces. In this study, we present a hybrid method combining nanosecond laser ablation and chemical modification to fabricate superhydrophobic aluminum surfaces. Three distinct micro/nanostructures are prepared and their CB state stability is evaluated through evaporation and underwater pressure tests. The results show that surfaces with conical microstructures exhibit the most stable CB state. Additionally, these structures can spontaneously transition from the Wenzel to CB state during icing/melting cycles, maintaining their superhydrophobicity after 15 cycles. This scalable, cost-effective method produces surfaces with excellent CB state stability and durability, making them promising for various industrial applications.