Several years ago, a team of researchers in Japan used a beam of light to move drops of oil around on a surface. They could not do the same thing with water drops, however. Now, with inspiration from lotus leaves, a second team has succeeded in manipulating water with a beam of ultraviolet light. That could open new routes for controlling biochemical reactions, the scientists say.
The difficulty of moving drops of water with light stems from the way water molecules interact with surfaces. In previous experiments, Antonio Garcia and his colleagues at Arizona State University in Tempe tried to sidestep that challenge by manipulating the drops on very smooth surfaces. Yet, while the