Springtail-Inspired Hierarchically Structured Polymer Films as Omniphobic Coatings for Directional Transportation of Liquids

Abstract

Slender springtails (Entomobrya nivalis) and orange springtails (Neanura muscorum) are capable of repelling water and organic liquids using the hexagonally arranged nanoscale waxy protrusions and microscale wrinkles on their cuticles to protect the skin-breathing arthropods against suffocation in diversified survival environments. The omniphobic hierarchical structures can even shed and directionally transport liquids along the longitudinal direction of the wrinkles. Bioinspired by springtails, monolayer colloidal crystals are self-assembled onto anisotropic microwrinkled substrates and serve as structural templates to pattern antiwetting hierarchical structure arrays. The dependence of structure configuration on the antiwetting performances is systematically investigated in this study. Impressively, the optimized structure array exhibits anisotropic omniphobic sliding characteristics toward liquids with varied surface tensions ranging from 72.8 to 27.2 mN/m. The springtail-inspired coatings undoubtedly have great potential for developing innovative applications that require directional transportation and the collection of liquids.