UV laser-ablated Cu superwetting surface with improved anti-icing and antibacterial properties

Abstract

Ultraviolet laser-ablated technique was used to improve the anti-icing and antibacterial properties of copper (Cu) with the objective of achieving efficient heat exchange performance. The laser scanning space interval exhibited a critical influence on the surface topography. SEM observation showed that nano-villi-like products appeared on the surface, which resulted in the formation of a micro/nano-hierarchical structure when the scanning interval was below 40 µm. When the scanning space interval was above 40 µm, the surface presented only a micron-level papilla/groove pattern without any nano-villi-like product. Combined analysis of XRD, TEM, and XPS results indicated that the nano-villi products were partially crystallized copper oxide particles with 5–10 nm size. It was speculated that nano-oxide was obtained by vapor deposition of Cu caused by laser ablation. Furthermore, after modification with FAS-17, the hydrophobicity of the nano-villi-like surface became significantly higher than that of the papilla/groove surface. The highest water contact angle reached 156.30 ± 0.53° and the water sliding angle was as low as 1.57 ± 0.99°. In the anti-icing test at − 10 °C, the delayed freezing time of this superhydrophobic surface reached 9923 s. This excellent anti-icing property can be attributed to the improvement in critical activation energy for ice nucleation and reduction in interfacial thermal conductivity caused by superhydrophobic surface. Finally, the inhibition zone test proved that laser ablation could significantly improve the antibacterial activity of Cu against E. coli and S. aureus.