Metallic superhydrophobic nanostructures via bottom–up synthesis: design, functionality, and applications

Superhydrophobic metallic nanostructures fabricated via bottom-up synthesis methods offer a versatile platform for advanced surface engineering, combining extreme water repellency with the inherent electrical, thermal, and mechanical advantages of pure metals. Techniques such as electrochemical deposition, polyol reduction, and galvanic replacement enable precise control over hierarchical morphologies-including nanowires, nanocones, and dendritic arrays-critical for stabilizing the Cassie-Baxter wetting state. Pure metals such as silver, copper, nickel, and aluminum provide distinct benefits, including high conductivity, mechanical robustness, plasmonic activity, and antimicrobial properties, which are directly exploitable without the complexity of composite systems. These nanostructures exhibit multifunctionality, enabling applications such as self-cleaning surfaces, electrothermal and photothermal anti-icing, oil-water separation, electromagnetic interference shielding, and wearable electronics. However, challenges remain in scaling production, minimizing the environmental impact of fabrication processes, and ensuring long-term durability under mechanical stress. Addressing these limitations will be pivotal for translating metallic superhydrophobic nanostructures into sustainable, real-world solutions across aerospace, biomedical, and environmental sectors.