Curvature-Enhanced Superomniphobic Property for Minimizing Contact Time of Low-Surface-Tension Liquid.

Abstract

In nature, the springtail represents an ideal superomniphobic system, exhibiting remarkable resistance to organic liquids in both static and dynamic states. This behavior is attributed to the hierarchical structure of their skin, consists of micro- and nanostructures. While numerous artificial superomniphobic surfaces have been developed to mimic its geometry and properties, previous designs are limited to flat surfaces and failed to incorporate the curvature of the springtail's cuticle. Here, a curved superomniphobic surface is first developed that mimics both the curved shape and hierarchical structure of springtail skin. This system developed on the flexible substrate reveals the significant role that curvature plays in reducing the contact time of low-surface-tension liquid. While the static repellency on curved and flat surfaces is comparable, droplet rebound dynamics are distinctive on curved surfaces, showing asymmetric bouncing that conforms to the curvature. This effect intensifies with increased curvature, leading to a reduction in contact time by up to 54%, a record for organic liquid. This study uncovers the crucial role of surface curvature in springtail superomniphobicity and offers valuable insights for designing advanced omniphobic systems.