Influence of fluence, beam overlap and aging on the wettability of pulsed Nd3+:YAG nanosecond laser-textured Cu and Al sheets

Superhydrophobic and hydrophobic surfaces on Al and Cu have a wide range of applications in electronics, industrial devices, air conditioning, and refrigeration plants, and home appliances due to their excellent electrical and thermal characteristics. In many of these applications, the wettability of their surface is essential. This work presents the fabrication of superhydrophobic and hydrophobic surfaces on Al and hydrophobic surfaces on the Cu metal sheets via laser processing and aging without any additional chemical treatment. Texturing with laser spot overlap is used to generate naturally formed nanoscale textures by scanning the whole sample surface. The influence of laser parameters on the dimension and shape of the fabricated surface textures and their impact on wettability is analyzed along with the evolution of wetting behavior over time. The laser textured surfaces, which are initially hydrophilic, are found to transform hydrophobic over time upon exposure to atmospheric conditions. Experimental evidence using X-ray photoelectron spectroscopy (XPS) and ATR-FTIR spectroscopy corroborates this transition is owing to the adsorption of organic molecules present in ambient. The depth profiling using XPS reveals carbon contamination around 60-70 nm from the sample surface. Furthermore, textures exhibiting static contact angles of up to similar to 154 degrees have been achieved with Al sheets, whereas contact angles up to similar to 122 degrees have been attained in the Cu sample. These experimental findings enable control of wettability of Al and Cu sheets through precise tuning of laser parameters for desired properties.

Automated summary

This study demonstrates the fabrication of superhydrophobic and hydrophobic surfaces on Al and Cu metal sheets through laser processing and aging, without the need for additional chemical treatment. The influence of laser parameters on the surface textures and wettability, as well as the transition from hydrophilic to hydrophobic behavior over time, are analyzed. The experimental findings highlight the ability to control the wettability of Al and Cu sheets by adjusting laser parameters.