Drop by drop
Two water drops illuminated with a fluorescent dye. The drop on the left (the one that appears round) is sitting on a nanowire surface with a very hydrophobic coating. The drop on the right, which is spread out, is sitting on a flat surface with the same coating. This picture shows that the nanowires create a lotus leaf-like surface. Arizona State University researchers have made that surface photoresponsive and can make the drop on the left move in response to light. Credit: Arizona State University.