Carbon nanotubes show a love/hate relationship with water

Researchers at the University of Pittsburgh have revealed that, as a coating, carbon nanotubes can both repel and hold water in place, a useful property for applications such as printing, spectroscopy, water transport, or harvesting surfaces. When water is dropped on a carbon nanotube forest, the carbon nanotubes repel the water, which forms a sphere. But when the drop of water is flipped over, it does not fall to the ground but rather clings to the surface.