Fig. 1 | Design of the microstructu

Fig. 1 | Design of the microstructure armour. a, Schematic showing the strategy for enhancing the mechanical stability of the superhydrophobic surface by housing water-repellent nanostructures within a protective microstructure ‘armour’. b, c, Schematics showing the mechanism by which abrasion damages discrete and interconnected microstructures. b, In the case of discrete microstructures, the abrading object can be easily inserted in between the microstructures and can damage both the nanostructure and the microstructure. c, Protection afforded by the topology of interconnected microstructures. Abrasion objects that are larger than the frame are blocked by the microstructure. d, Relationship between the apparent contact angle θ* and the liquid–solid contact fraction f for an ideal Cassie–Baxter state at two different values of the Young’s contact angle θY. e, Cross-section showing the change of contact area on the top of the framework structures when the height h is fractured to half of its original value by abrasion (see Supplementary Fig. 3 and Supplementary Discussion section 2.2 for details). f, Influence of mechanical stability and change of the liquid–solid contact fraction Δf micro as function of the sidewall angle (α) (see Supplementary Fig. 3 and Discussion section 2.2 for details).