A team of researchers has found inspiration in an unlikely critter: the humble Namib Desert beetle, a south African species that gathers water molecules straight from the air. The beetle does this by developing a pattern of water-attracting and repelling molecules on its wings and trapping water molecules in these peaks and troughs.
The scientists took a cue from this and created a mat capable of absorbing water molecules from the air with billions of tiny carbon tubes. Here's how it came about:
The researchers applied two polymer layers—a water-loving one on top and a water-repelling one on the bottom—to a 1-centimetre-high forest of thin cylinders of carbon atoms, called carbon nanotubes. Once finished, the top layer draws water molecules into the forest, without any need for an external power source, the team reports online this month in ACS Applied Materials & Interfaces. Having been drawn inside the forest, the moisture is contained by the water-repelling bottom and sides of the structure—although some can be lost to evaporation over time. Like a sponge, the forest can simply be squeezed to release the water it has collected, after which the material can be reused.
Obviously, the more humid the air, the more water the mat collects. But even in early tests in dry environments, the researchers found that a 8-milligram mat absorbed more than a fourth of its weight in water over 11 hours.
It's still early days, but imagine the implications. Harvesting water, which is particularly challenging in dry regions of the world, would be much, much simpler than current methods. And who wouldn't want to walk around in hot, summer days with a magical sponge that automatically fills up with water? [Science magazine]
Top image credit: Science magazine