Beetle-Inspired Bumpy Materials to Trap & Control Droplets

In Africa's Namib Desert, fog-filled morning wind carries the drinking water for a beetle called the Stenocara. Tiny droplets collect on the beetle's bumpy back. The areas between the bumps are covered in a waxy substance that makes them water-repellant, or hydrophobic. Water accumulates on the water-loving, or hydrophilic, bumps - forming droplets that eventually grow too big to stay put, then roll down the waxy surface. Over a decade ago, news of this creature's efficient water collection system inspired engineers to try and reproduce these surfaces. Using various methods to create intricately patterned surfaces, engineers can now make materials that closely mimic the beetle's back. Engineers can create materials that repel liquids so well they're called superhydrophobic; many superhydrophobic surfaces created by chemical coatings are already in the marketplace. Funded by the National Science Foundation, mechanical engineer Constantine Megaridis at the University of Illinois at Chicago has used beetle-inspired designs to put precise, textured patterns on inexpensive materials, making microfluidic circuits. By varying the layout of these surfaces, researchers can now trap, direct, and repulse small amounts of water for a variety of new purposes.