Demonstration of an enhanced “interconnect topology”-based superhydrophobic surface on 2024 aluminum alloy by femtosecond laser ablation and temperature-controlled aging treatment

Superhydrophobic surfaces are currently under intense investigation due to their superb properties and enhanced performance. Along these lines, in this work we present a novel designing scheme consisted of five different microstructures (cone structure, pyramid structure, cone ridge structure, adhesive structure, and interconnect topology structure). The static properties, as well as the wettability of all configurations, are evaluated by applying both a comprehensive numerical model as well as a mathematical approach for the wettability contact issue. From our analysis, it is apparent that the interconnect topology structure exhibits better mechanical durability and superhydrophobicity characteristics compared with the other four compounds. The structures were fabricated by employing a femtosecond laser technique on 2024 aluminum alloy surfaces. The interconnect topology structure is a complex micronano unit composed of alternating arrays with holes and bumps while the other configurations are single micronano units with protruding-like monomer shapes. Meanwhile, a low-cost, nonpolluting, high efficiency, and quantitatively controlled method for preparing superhydrophobic surfaces, which is called temperature-controlled aging treatment (TCAT), is proposed. All the above-mentioned structures obtained the superhydrophobic surfaces after imposing the TCAT step (150 °C, 3-6 h). Insights from XPS measurements demonstrate that the wetting modification stems from the decomposition and remodeling of the certain hydrophilic/hydrophobic functional groups at different stages. Among the five kinds of structures, the interconnect topology structure has obvious advantages in terms of improved static properties and wettability transformation after the elapse of 200 days of static storage in the air, especially in the realization of the superhydrophobicity effect.