Investigation on the differences of surface cleaning properties of series of superhydrophobic aluminum alloys

Abstract

Due to the metallic activity of aluminum, superhydrophobic surfaces are often prepared on aluminum substrates by chemical etching method. However, there are differences in the properties of superhydrophobic surfaces prepared from different series of aluminum alloys. Here, aluminum alloys of the brands 1060, 2024, 5052, 6061 and 7075, which are commonly used in industry, were chosen as experimental subjects and fabricated into different superhydrophobic or hydrophobic aluminum surfaces (SH-HAS) by the same chemical etching method. The effects of different micro-nano structures on surface wettability, mechanical durability, anti-icing and self-cleaning properties were investigated. The results showed that the surface microscopic morphology of different aluminum alloys after etching differed significantly. Different micro-nano structures would determine the surface roughness and the actual liquid-solid contact area of SH-HASs, resulting in different contact angles (CA) and sliding angles (SA). Further experiments demonstrated that SH-HASs with larger CA and smaller SA exhibited more superior anti-icing properties, while those with larger hardness and surface roughness had greater mechanical durability. In addition, all five SH-HASs had excellent self-cleaning properties that would positively impact the anti-fouling and de-fouling of aluminum products and equipment.