One-step generation of ultrahydrophobic aluminum surface patterns by nanosecond lasers

Abstract

In recent years, metal surfaces that could mimic the water repellence properties of some natural surfaces have been the area of an intense research due to their potential applications such as self-cleaning, anti-contaminating and anti-sticking applications. Ultra short laser machining/structuring is a promising technique to obtain the dual scale roughness on the metal surface, which promotes the complex interfaces between solid-liquid-air, thus improves the wetting property of the surface. An attempt was made to study the improvement of wetting properties of aluminum by nanosecond laser source in one step process. Flat aluminum sheets of thickness 100 μm were laser machined with ultraviolet laser pulses of 30 ns with different laser parameters to optimize the process parameters. The samples produced at the optimum conditions with respect to contact angle measurement were subjected to microstructure and chemical analysis. The wetting properties were evaluated by static contact angle measurements on the laser patterned surface. The laser patterned microstructures exhibited ultrahydrophobic surface with a maximum contact angle of 180° for the droplet volumes of 8μL.