Comparative study of fabricated superhydrophobic surfaces via LST with carbon soot, chemical etching and auto-oxidation

Abstract

The present work aims to fabricate superhydrophobic surfaces (SHS) on commonly used low carbon steel (AISI 1018). Laser surface texturing (LST) was used for creating circular textures on substrate while varying the diameter and pitch of the texture geometry with the help of fiber laser machine. Three different methods, (a) LST followed by waxing and candle sooting, (b) LST followed by chemical etching, and (c) LST followed by auto-oxidation were introduced to fabricate SHS and to make a comparison among them. Also, the mechanical stability and durability of the modified surface via these methods were evaluated by the mean of small-scale laboratory wear tests like tape peeling, sand abrasion, and water impact test. The developed surfaces were characterized for surface roughness, FESEM analysis, EDS analysis, besides water contact angle (WCA) and sliding angle (SA) have been evaluated. The highest WCA and lowest SA were discovered on textured and chemical etched followed by dip coated specimens and was found to be ~159° and ~5° respectively. However, the auto-oxidized laser textured samples showed best results among other methods in terms of mechanical stability. These processes are simple, effective and can be of great interest for producing SHS for various industrial applications.