Figure 4.

Illustration of mechanism: (a) on the SNAs surface, water penetrates to the bases of the cones and spreads out (the inset is side view, after water contact); (b) on the SNAs surface modified with PFTES many air pockets exist between SNAs (the inset shows that a water droplet easily rolls away at very small tilt angle); (c) on GNSs/SNAs surface water cannot penetrate into the nano-gaps between the GNSs but does go partway into spaces between cones (the inset is side view of water CA 164°); (d) on the GNSs/SNAs surface modified with PFTES water also cannot penetrate into the nano-gaps between the GNSs, and it cannot go into spaces between cones as deeply as in unmodified samples (the inset is side view of water CA 155°).