Laser patterning for fast production of superhydrophobic copper with delayed formation of patina and maintenance of surface electrical conductivity

The wettability of copper can be modified using laser patterning, allowing the surface to achieve a superhydrophobic behavior after aging in ambient conditions or in a faster way when combined with a green engineering method (heating in an ethanol bath). The surface chemistry of copper irradiated with a 355 nm pulsed laser was studied using Raman spectroscopy and Fourier transform infrared measurements allowing to discuss the mechanism responsible for the wettability change. It was found that the adsorption of organic compounds rather, than the reduction of CuO to Cu₂O previously presented in the literature as the dominant effect, is what plays a key role in this process. Moreover, the superhydrophobic copper presents an ability to delay the formation of patina allowing the copper surface to keep its electrical conductivity for a longer time when compared with non-irradiated copper exposed to the same conditions. Copper and its alloys are widely used in applications that take advantage of their electrical conductivity, so the reported strategy to maintain the electrical conductivity of the surface presents remarkable interest.