Scalable Wettability Modification of Aluminum Surface through Single-Shot Nanosecond Laser Processing

Abstract

Conversion of a regular metal surface to a superhydrophobic one has great appeal because of the wide range of potential applications such as anti-fouling, anti-corrosion, and anti-icing. One promising technique is to modify surface wettability by laser processing to form nano-micro hierarchical structures with various patterns, such as pillars, grooves, and grids, followed by an aging process in the air or additional chemical processes. Surface processing is typically a lengthy process. Herein, we demonstrate a facile laser technique that converts the surface wettability of aluminum from inherently hydrophilic to hydrophobic and superhydrophobic with single-shot nanosecond laser irradiation. A single shot covers a fabrication area of approximately 19.6 mm2. The resultant hydrophobic and superhydrophobic effects persisted after six months. The effect of the incident laser energy on the surface wettability is studied, and the underlying mechanism of the wettability conversion through single-shot irradiation is suggested. The obtained surface shows a self-cleaning effect and the control of water adhesion. The single-shot nanosecond laser processing technique promises a fast and scalable method to produce laser-induced surface superhydrophobicity.

Determining the Role of Oxygen in Obtaining Long-Term Stable Superhydrophilic Surfaces on Metals Treated with a Femtosecond Laser

“…It is important to understand how to fabricate the desired topography and impose favorable chemistry on engineering metal substrates for desired wettability. It has been widely demonstrated that the wettability state of a solid surface can be changed by micro/nanostructuring of the surface. − Fabrication techniques such as thermal oxidation, chemical vapor deposition, laser structuring, and plasma spray were widely used to create wetting properties based on two primary factors, and those are surface chemistry and surface micro-/nanostructures. − Laser processing of metal surfaces is a reliable technique to produce superhydrophilic or superhydrophobic materials, depending on the surface energy of the material. − Furthermore, a femtosecond laser with its good consistency, high precision, and negligible heat-affected zone is a one-step solution for creating multifunctional surfaces. Modification of the surface morphology under ultrafast laser irradiation is mainly carried out by ablation of a localized area with a focused beam, which makes it possible to change both the chemical composition of the material and the surface microstructure. − …”