Feasibility of Inducing Superhydrophobicity on Laser-Textured Surfaces: Development of Mathematical Model and Experimental Investigations

Abstract

Hydrophobicity is a prominent characteristic of a surface that governs its applications in domains such as wear reduction by lubrication retention, self-cleaning surfaces, fluid drag reduction, viscosity testing, development of oleophobic coatings, etc. A superhydrophobic surface exhibits a water contact angle (CA) of 150∘ or larger. High surface energy of nontextured surface limits its wettability. Texturing of a surface imparts low surface energy which proves to be favorable for enhancing the overall surface hydrophobicity. Research and analysis done to fathom an optimum method by which surfaces accomplish superhydrophobicity is still miniscule. It is challenging to fabricate superhydrophobic surfaces by micro-machining due to the expansive range of the features involved. To minimize the exorbitant costs incurred due to trial-and-error-based experimentation, a mathematical model with >90% accuracy has been developed in this study, which would help determine the closest ranges of values of parameters like micro-dimple diameter and areal density responsible for inducing superhydrophobic properties on a micro-dimpled specimen. The exceptionality of this study lies in the fact that though mathematical models are available for textures like micro-grooves and micro-pillars, but miniscule research is available for micro-dimpled surfaces with hardness greater than 55 HRC.