Figure 7.

(a) Water collection rates per unit surface area for single cylinder and cone, ungrooved and grooved with homogeneous wettability at 0° inclination. The left side shows the data when water was collected under the entire surface. The right side shows data when the water was collected at the base (as in nature). At the base, a cone collects more water than the cylinder whereas total water collection rates are comparable. Grooved cones have higher collection rates than ungrooved. (b) The optical images show movement of the water droplets on cylinders and cones in complete collection. (c) The top shows optical images of a droplet sitting on an ungrooved cone and a grooved cone; the grooves elongate the droplet. The bottom shows comparison of weights and frequency of droplets in complete collection at the base. Grooved cones collect heavier droplets and frequency of droplets falling is comparable. (Online version in colour.)