Formation mechanism of superhydrophobicity of stainless steel by laser-assisted decomposition of stearic acid and its corrosion resistance

Abstract

Superhydrophobic surfaces have attracted extensive attention over the past decade, primarily due to their self-cleaning, corrosion resistance and anti-bacterial abilities. However, it is still a challenge to prepare superhydrophobic surfaces with good chemical stability, low cost, environmental friendliness, and suitable for large-scale production applications. In this paper, a hybrid laser-chemical method to prepare superhydrophobic micro-patterns on 316L stainless steel were put forward, which combined laser ablation and laser assisted chemical decomposition of stearic acid (C17H35COOH). Experiments show that under the laser power of 10 W, the frequency of 150 kHz, the speed of 20 mm/s, and the mesh spacing of 75 μm, the best superhydrophobicity with a static contact angle of 153.9° can be obtained. The fundamental mechanism of laser-chemical method is the increase of the non-polar CC(H) bond of specimen by laser assisted hydrodeoxygenation reaction of stearic acid. Moreover, unlike laser ablation-stearic acid coated specimen, the specimen prepared by laser-chemical method can maintain superhydrophobicity after 10 min of ultrasonic cleaning. The electrochemical corrosion experiments shows that the hybrid laser-chemical method can manufacture superhydrophobic specimens with better chemical durability and corrosion resistance.