Tunable pulsewidth nanosecond laser texturing: From environment friendly superhydrophobic to superamphiphobic surfaces

Controlled wetting of metallic surfaces is highly interesting in many practical applications, from self-cleaning to drag reduction. Laser processing to obtain micro-/nano-textured surfaced to obtain superhydrophobic has mainly leveraged expensive and low throughput pico-/femto-second ultrashort pulse lasers. In this study, we demonstrate the micro/nano-texturing of an aluminum surface with a nanosecond laser and the possibility of tuning the repelling properties by varying the laser pulse duration in the range 4–50 ns, and the scan line spacing in the range 40–140 μm. We also compare two different surface treatment approaches based on a fluorosilane and a flaxseed oil vapor coating obtaining superamphiphobic and superhydrophobic behavior, respectively. In the case of oil vapor treated superhydrophobic surface, we developed an inexpensive, environment-friendly, faster, and simpler surface treatment for hydrocarbon adsorption-based superhydrophobicity (contact angle ∼ 160°), providing an alternative to silane-based coatings. Static and dynamic characterization of the surfaces obtained showed good performance, also demonstrating a self-cleaning property. These surfaces also demonstrate a good durability in line with the state-of-the-art. The combination of nanosecond laser texturing and the coating treatment proposed has the potential for scaling in many industrial applications given the ease of processing.