Development of Superhydrophobic Coating on Copper for Enhanced Corrosion Resistance in Chloride Medium
In this paper, a simple and economic method of superhydrophobic (SHP) surface modification of copper surfaces with water contact angle (WCA) of 147° ± 0.1° and roll-off angle of 5° is reported. SHP copper surfaces were synthesized by annealing copper foil in air and then coated with silica nanoparticles dispersed in silane solution. Scanning electron microscopy analysis of the SHP Cu surfaces showed the uniform distribution of spherical micron-sized CuO particles throughout the surface. Atomic force microscopy images of silane-coated surfaces showed increased valleys and peaks with higher root mean square and average roughness contributed by the silica nanoparticles. X-ray photoelectron spectroscopy results further confirmed the micron-sized CuO particles in the outer layer with silane containing silica nanoparticles, which contributed to the micro-/nano-roughness causing a phenomenal improvement in the WCA values. Electrochemical studies carried out in aqueous chloride environments demonstrated the corrosion resistance of superhydrophobic copper surface as evident from the shift in open-circuit potential values towards the nobler direction, increase in the charge transfer resistance and lower anodic current as compared with the fresh copper foil.
KeywordsSuperhydrophobicity Annealing Water contact angle Corrosion Durability Electron microscopy
The authors would like to acknowledge Mr. Satyabrata Mishra, RRDD and Mr. C. Thinaharan, CSTD, IGCAR, for ATR-IR, XRD and XPS characterizations, respectively.
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