Mimicking the Namib Desert Beetle with Hydrophilic and Hydrophobic Surfaces

The Namib Desert beetle, Stenocara gracilipes, condenses fog that rolls in off the west coast of Namibia to provide itself with the water it needs for the day. By lifting its abdomen into the air to collect the water vapor, it condenses on hydrophilic bumps that are about 500μm in diameter and are spaced apart about 500-1500μm. Once the water reaches a critical size, the droplet rolls off the hydrophilic bump and onto the flat hydrophobic surface of the elytra. Since the beetle is angled with its abdomen in the air, the water rolls down to its mouth. A design could be created to help costal regions that experience drought get potable water. This was done using glass beads as hydrophilic bumps on a polystyrene background to act as the hydrophobic surface. An alternative was explored using glass beads modified with hydrophobic agents: octadecyltrichlorosilane (OTS) and decyltrichlorosilane (DTS), to generate hydrophobic bumps and using nail polish as the hydrophilic background since it contains nitrocellulose which is hydrophilic. This was done to determine if the beetle’s characteristics could be improved. Overall, there was no significant difference between the designs’ water condensation capability to say that one was better in the end