Hyperelastic superomniphobic surfaces via microprotrusion-induced stress redistribution

Abstract

In this work, we report hyperelastic superomniphobic surfaces that have been engineered to retain superomniphobicity, without coating delamination, even at 400% strain and after thousands of stretch–release cycles. To achieve such hyperelastic superomniphobic surfaces, we introduce a novel design – an array of discrete microprotrusions on the hyperelastic material that redistribute the stresses out-of-plane during elongation. Such an out-of-plane redistribution of stresses results in nearly stress-free tops of the microprotrusions, allowing the coating to be virtually intact even after 5000 stretch–release cycles. Furthermore, through systematic experiments and theoretical analysis, we studied the influence of elongation on contact angles, sliding angles and breakthrough pressures on our hyperelastic superomniphobic surfaces. We envision that our robust hyperelastic superomniphobic surfaces will have a wide range of applications in wearable electronics, textiles, artificial skins, droplet manipulation and protective wraps.