Figure 3.

(a) Shape of a water droplet on the sample's surface, indicating its large CA of 164° (the inset is side view of 5 μL water droplet). (b) Shape of water on the sample's surface when the sample is turned upside down (the inset is the side view of 75 μLwater droplet). (c) Receding angle of water droplet when withdrawing water. (d) Advancing angle of water droplet when adding water. (e) Force-distance curves recorded before and after 5 μL water droplet contacted the as-prepared hierarchical structure. (f) Slide angle of a 100 μL water droplet on the verge of motion.