Investigation of wetting properties of gold nanolayer coated aluminum surfaces textured with continuous-wave fiber laser ablation

Abstract

This paper describes the fabrication of superhydrophobic surfaces on aluminum plates coated with 15 or 40 nm gold nanolayers by a continuous-wave fiber laser ablation in ethanol. Laser ablation resulted in the creation of Al2O3 microstructures combined with Au micro/nanoparticles on the Al surface. Significant structural evolutions such as reduction of micro/nanostructure size and the percentage of the oxygen concentration were observed on the surfaces by increasing the thickness of the Au nanolayer. In addition, the fabricated Au and Al2O3 nanoparticles separated from the Al surface were non-spherical and roughly spherical in shapes, respectively. The static water contact angle technique to the evolution of wetting properties was employed. The laser-ablated Al sample with a 40 nm Au layer demonstrated a near superhydrophobic surface with a water contact angle of 152 ± 2°. The results of the various characterizations showed that the surface topography was the dominant factor in specifying the degree of hydrophobicity.