Superhydrophobicity on hierarchical periodic surface structures fabricated via direct laser writing and direct laser interference patterning on an aluminium alloy

Multi-scaled hierarchical surface microstructures are fabricated on Al2024 alloy using Direct Laser Writing and Direct Laser Interference Patterning. During the manufacturing procedure two distinct laser sources are used, including an ultra-violet nanosecond laser system that produces microcell structures with different dimensions through Direct Laser Writing. Posteriorly, an infrared picosecond laser source is used to fabricate sub-micron features on the previously patterned microcells. Thus, the fabricated multi-scaled hierarchical structures are a closer representation of what is observed in nature. Water contact angle measurements are carried out in order to assess the wettability response, which revealed superhydrophobicity one week posterior to the fabrication, with measured contact angles up to 161.5 ± 3°.