Lotus-leaf-like microstructures on tungsten surface induced by one-step nanosecond laser irradiation

A method of one-step nanosecond laser scanning irradiating was employed to produce microstructures on tungsten surfaces. The effect of the laser fluence, scanning speed and scanning interval on the morphology of tungsten surfaces was investigated. The results indicated that higher laser fluence along with smaller scanning interval and lower scanning speed was more beneficial for obtaining lotus-leaf-like hierarchical microstructures. When the laser fluence was >1.8 J/cm(2) at the scanning speed of 10.0 mm/s and interval of 1.0 mu m, lotus-leaf-like hierarchical microstructures were produced on tungsten surfaces, on which the WCAs of 5 mu l water droplets were measured as low as 0 degrees. Superhydrophobic surfaces with a maximum WCA of 162 degrees and a minimum rolling angle of 1.0 degrees were further obtained from fluoroalkylsilane modification on the superhydrophilic surfaces. The availability of tungsten surfaces with controllable wettability from superhydrophilicity to superhydrophobicity was meaningful for the application of tungsten-based components in various fields. (C) 2016 Elsevier B.V. All rights reserved.