Approaches to design a surface with tunable wettability: a review on surface properties

Abstract

Due to the wide application prospects in energy harvesting, conversion, and emission control technology, wettability has gathered momentum in recent years. Surface wettability alteration by nanomaterial fabrication and coating is of recent interest among researchers to attain desirable wetting surfaces. The wettability of liquid over a surface changes with surface properties such as roughness, surface energy, porosity, capillarity, and structure. Eventually, surface chemistry plays major role in changing surface energy which in turn leads to wettability alteration toward wetting and non-wetting extents. Herein, the dependence of surface properties in wettability alteration has been analyzed with the literature reports. Furthermore, surface pre- and post-treatments such as laser, ozone plasma, and UV irradiation contribute to change of surface energy inducing the liquid to encroach toward superhydrophilicity and superhydrophobicity. This review article analyzes the properties that induces wetting and non-wetting ability of liquids over surfaces. Theoretical models opted for wettability determination has been accounted to study the contribution of roughness, porosity, and surface energy. The article provides a clear idea of properties involved in wettability alteration with respect to wide range of applications in energy conversion, oil–water separation, self-cleaning, bio-adhesion, and bio-molecular immobilization.