Nanometre-sized rods of carbon can expel water in puffs of vapour when the air is already humid.
Materials such as carbon and silica gels typically pick up moisture as humidity increases. But Satish Nune and his colleagues at the Pacific Northwest National Laboratory in Richland, Washington, found that their carbon-based nanorods take up water at low humidity and then give off about half of it when the relative humidity exceeds 50–80%. The team thinks that water condenses between adjacent rods and then capillary forces draw the rods together until the water bursts from the ends of the rods and evaporates.
Nature Nanotechnol. http://dx.doi.org/10.1038/nnano.2016.91 (2016)