Figure 10

(a) Optical image of 20 µL droplet on dusty hydrophobic surface. Dust thickness is 50 µm. (b) Optical image of 20 µL droplet on dusty hydrophobic surface. Dust thickness is 100 µm. (c) Optical image of 20 µL droplet on dusty hydrophobic surface. Dust thickness is 150 µm.