Non-fluorinated superomniphobic surfaces

Superomniphobic surfaces, capable of repelling a wide range of liquids, including low-surface-tension oils, rely on a synergy between surface chemistry and texture. For decades, these surfaces have primarily relied on per- and polyfluoroalkyl substances (PFAS) due to their exceptional repellency and durability. However, the persistence of PFAS in the environment and their toxicological risks have triggered global regulations to phase out their use. This transition presents substantial challenges, especially in sectors such as textiles, food packaging, and electronics, where oil and chemical resistance are essential and fluorine-free alternatives remain limited. While recent research has made progress in developing PFAS-free superhydrophobic surfaces, there remains a significant gap in understanding and designing non-fluorinated superomniphobic systems. This review provides a comprehensive overview of recent strategies for achieving superomniphobicity without fluorinated chemistry. We discuss both texture- and chemistry-based approaches, including coatings made with silica nanoparticles, treated fabrics, and metal oxide nanostructures, as well as coating-free systems that leverage advanced 3D-printing to fabricate doubly and triply re-entrant geometries. Importantly, we highlight limitations in scalability, durability, and liquid-specific performance. By identifying key material and structural design considerations, this review offers a clear perspective on current challenges and emerging opportunities for creating sustainable, high-performance, PFAS-free superomniphobic surfaces.