Directional and sustainable transportation of water droplets using lubricated carbon fibers on a superhydrophobic substrate

Directional transportation of water droplets on solid surfaces has been extensively studied over the past century owing to its scientific and engineering significances. In contrast to the wettability/stiffness/structure gradient methods, we present a new approach using lubricated carbon fiber tracks. The transportation process with different widths of the fiber, the substrates and the sizes of the droplet is tested and analyzed. Two failure modes of the transportation are characterized, which allows the passage of the droplet with a certain range of sizes. These insights are possible to manipulate droplets directionally and selectively, without changing the substrate. We anticipate that this transportation technique will find an extensive range of applications.