Large spot diameter nanosecond laser treatment of aluminum alloy sheets for high-speed superhydrophobic hierarchical micro- and nanostructured surface preparation

Nanosecond laser-induced fabrication of superhydrophobic surfaces has become a research focus of functional surfaces studies in recent years. In this study, we present a novel and highly efficient method for fabricating a superhydrophobic functional aluminum alloy surface. The method is based on large spot diameter (d = 960 μm) infrared nanosecond laser high-speed (linear velocity v = 3 m/s) scanning and ablation of the surface followed by low surface energy agent chemical treatment to attain a superhydrophobic state on the aluminum alloy surface. The textured roughness surfaces show three specific micro-morphology characteristics including corrugated, mastoid and flat zones all densely covered by cauliflower-like nanostructures. The hierarchical micro- and nanostructured surfaces demonstrated outstandingly stable superhydrophobicity during long-term exposure to an ambient atmosphere. The proposed method proves that large spot diameter high-speed scanning low-cost nanosecond lasers are also suitable for fabrication of large area metallic superhydrophobic surfaces for practical industrial application.