Surface Repellency beyond Hydrophobicity: A Review on the Latest Innovations in Superomniphobic Surfaces

Superhydrophobic surfaces have long faced challenges in repelling low-surface-tension liquids like oil and alcohol, limiting their practical applications. Over the past few years, researchers have been actively looking for new alternatives to overcome this issue. Recently, superomniphobic surfaces have attracted significant interest due to their ability to repel both high- and low-surface-tension liquids. Compared with superhydrophobic surfaces, superomniphobic surfaces provide enhanced liquid repellency, making them more suitable for industrial and real-world applications. This Review explores the recent advancements in the fabrication of superomniphobic surfaces. Three basic wetting principles, Young's, Wenzel's, and Cassie-Baxter's equations, are discussed. The vital role of low surface energy and high surface roughness of hierarchical and re-entrant structures in achieving a steady Cassie-Baxter state that has a low contact area between the solid surface and liquid droplet is emphasized. Additionally, a comprehensive description of various fabrication techniques, characterizations, and practical applications of superomniphobic surfaces is provided. Finally, the challenges and future prospects regarding this research area are addressed. This comprehensive review aims to inspire researchers to refine and enhance current development methods of superomniphobic surfaces and stimulate further exploration in the research field.