Scalable Engineering of Superhydrophobic Copper Surfaces with Enhanced Corrosion Resistance by Combined Nanostructuring and Chemical Vapor Deposition

The vulnerability of copper to corrosion in humid and saline environments remains a critical challenge for its long-term use. In this work, we present a streamlined and scalable approach for fabricating superhydrophobic, corrosion-resistant copper surfaces by integrating a simple wet chemical oxidation process with atmospheric pressure chemical vapor deposition (APCVD) of a perfluorinated silane. The hierarchical CuO nanostructures formed via alkaline oxidation serve as a robust layer, while subsequent silane functionalization imparts low surface energy, resulting in surfaces with water contact angles exceeding 170° and minimal contact angle hysteresis. Comprehensive surface characterization by SEM and roughness analysis confirmed the preservation of hierarchical morphology after coating. Wettability studies reveal a transition from hydrophilic to superhydrophobic behavior, with the Cassie-Baxter regime achieved on nanostructured and silane-functionalized samples, leading to enhanced droplet mobility and self-cleaning effect. Salt spray tests demonstrate that the superhydrophobic surfaces exhibit a corrosion rate reduction of 85.7% (from 2.51 mm/year for bare copper to 0.36 mm/year for the treated surface), indicating a seven-fold improvement in corrosion resistance compared to bare copper. This methodology offers a practical, reproducible route to multifunctional copper surfaces, advancing their potential for use in anti-fouling, self-cleaning, and long-term protective applications.