New device blends secrets of beetles and cacti to pull water from fog
https://massivesci.com/articles/water-biomimicry-cactus-beetle-desert/
Yahui adapted the lessons from the cactus and the beetle. Everything about these organisms’ natural water collection processes happens on the surface, so Yahui’s team created their device on a piece of aluminum foil. To encourage condensation, they pressed bumps into the foil, which is coated with a pattern of alternating hydrophilic and hydrophobic spots, just like on the beetle’s back. Fog collection devices rely on the movement of fog across the surface, but air comes to a near standstill when it gets close enough to the surface to condense. (This slowdown at surfaces is the same reason why blowing dust off of your glasses doesn’t work for some of the smaller, more stubborn specks.) However, at the top of each bump on the foil, the air will move faster, so it is constantly refreshed with more fog.
Once the water is condensed it must be moved out of the way, so a pattern of holes is cut into the foil to allow the water to flow out underneath. The bottom of the foil is treated with a more hydrophilic coating than on its top, so just like on the cactus spines, water is forced toward the bottom. In this case, the gradient in hydrophobicity causes each droplet to be sucked away through the hole.
For a landlocked or arid regions, desalination of oceanwater is not an option and other methods like wastewater treatment can be inaccessible. Extracting water from the air, however, requires no electricity and mostly likely little maintenance. In the remote areas of Peru, mesh nets are suspended above misty hillsides to collect water, just like a spider’s web collects dew in the morning. Cacti and desert beetles provide examples of specialized adaptations. But nature is teeming with even more, like unidirectional water flow on the mouths of pitcher plants and the superhydrophobic surface of the lotus leaf.
#WatchTheWater