Superhydrophobic Textiles: Review of Theoretical Definitions, Fabrication and Functional Evaluation

Abstract

Engineering of superhydrophobic textile surfaces has gained significant scientific and industrial interest for its potential applications in outdoor wear and protective textiles, resulting in many publications especially on theoretical models and fabrication methods. In this review, progress in theoretical definitions to explain the wetting behavior and realization techniques for superhydrophobic textile surfaces is discussed. Firstly, theoretical models from Young, Wenzel, and Cassie-Baxter to the more recent re-entrant angle model are overviewed to understand the design strategy for superhydrophobic surfaces. Secondly, major surface manipulation techniques to produce superhydrophobic textiles were reviewed for: modification of surface energy, addition of surface roughness by depositing or growing nanoparticles either in spherical form or in high aspect ratio, etching by plasma or caustic chemicals. Particular attention is paid to evaluation methods to measure the level of hydrophobicity for superhydrophobic textile surfaces, as a limitation of static water contact angle (WCA) on differentiating superhydrophobic surfaces has been reported elsewhere. The challenges in application of superhydrophobic textiles to clothing materials in terms of comfort properties and durability are discussed with the suggestion of further research opportunities to expand the application.