Design considerations to fabricate multifunctional superomniphobic surfaces: A review

A surface possessing repellency to low surface tension liquids e.g., oils and alcohols (superoleophobic) and high surface tension liquids e.g., water (superhydrophobic) is referred to as superomniphobic. Such surfaces are receiving great attention as they can be used in a myriad of industrial and biomedical applications. In this timely review, we discuss the challenges in systematic design and fabrication of superomniphobic surfaces. Particular attention was paid to elucidating the significance of surface energy, roughness and the critical role of re-entrant texture in obtaining the Cassie-Baxter state. We also discussed how hierarchical scales of texture can yield high contact angles and decrease the hysteresis in the contact angle of superomniphobic surfaces by reducing the solid-liquid contact area. On this premise, we discussed design parameters that would allow efficient fabrication of superomniphobic surfaces leading to newer applications and horizons in the field. The review concludes by identifying newer challenges and potential for these surfaces.