Researchers at the Department of Energy's Pacific Northwest National Laboratory (PNNL) were attempting to make magnetic nanowires when by accident they created something far more interesting and promising. When inspecting their failed experiment with a vapor analysis instrument and high powered microscope they were astonished to see the carbon-rich nanorods oozing water whenever the humidity in the specimen holder was 50 to 80 percent.
After replicating this event dozens of times where the nanorods absorbed water in low humidity and then released it as water vapor in high humidity, the researchers realized that this material they created could have huge life-improving benefits like low-energy water harvesting and purification in arid and developing regions or fabrics that pull sweat away from the body and release it as water vapor to keep people comfortable in extreme temperatures or while exercising.
"Our unusual material behaves a bit like a sponge; it wrings itself out halfway before it's fully saturated with water," explained PNNL post-doctoral research associate David Lao, who manufactured the material.To be able to turn the material into those life-changing applications, the researchers first have to figure out how to control the nanorods size and shape and they have to understand what exactly is causing the nanorods to act like a sponge wringing itself in high humidity.
The team searched through scientific journals and found a couple of similar discoveries that helped to explain what might be happening with their material. PNNL explains:
"Armed with this knowledge, the PNNL team hypothesized water was condensing and forming a bridge between the nanorods, through a process known as capillary condensation. Next, they believe water between rods forms a curved cavity whose surface tension pulls the adjacent rods closer together. When two intersecting nanorods reach about 1.5 nanometers apart, the team reasoned, the water caught between them could be forced to quickly evaporate."
With an understanding of the phenomenom, the researchers believe that large amounts of the nanomaterial could be used to harvest and collect water for drinking in areas where clean drinking water is scarce. The researchers say it's a breakthrough in water purification and separation.
You can watch the nanorods expel water under microscope below.