Facile fabrication of superhydrophobic alloy surface based on room temperature vulcanized silicone modification

Superhydrophobicity of alloy surfaces is generally determined by the low-energy chemical composition and geometric structure of the surface. The appropriate geometry on alloy surfaces can be easily constructed via chemical etching methods. However, the subsequent low-energy modifications for pre-etched alloys are time-consuming or expensive, thus preventing their further application. Here, we prepared superhydrophobic alloy surfaces based on combining wet chemical etching and room temperature vulcanized (RTV) silicone treatment. Compared to traditional immersion methods, RTV silicone treatment for superhydrophobic 6061 Al alloy surfaces needs only 30 s, which is several thousand times faster than stearic acid or polymethyl triethoxy silane solution treatment. Mechanisms of RTV silicone treatment were investigated. The results show that dip-coating modification is different from these traditional methods. We found that the optimized proportion for RTV silicone rubber is HPDMS, PMTSi, and DBTDL with hexane solvent (HPDMS:PMTSi:DBTDL:hexane = 4:3:1:46, weight ratio), and the water contact angles of treated surfaces of pre-etched 6061 Al alloy, pure Al, and steels are 159° ± 2.7°, 168° ± 1.2°, and 169° ± 1.5°, respectively. Herein, our results demonstrate a facile, low-cost strategy to fabricate superhydrophobic alloy surface that is notable and easy to scale up for industrial applications.