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

• The effect of a nanosecond pulsewidth for laser textured superhydrophobic surfaces to tune the wetting properties. • Superamphiphobic and superhydrophobic surfaces were obtained with fluorosilane and flaxseed oil vapor based coating. • Use of an environment friendly flaxseed oil vapor for laser textured superhydrophobic surfaces. • Demonstration of self-cleaning 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 20-100 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.