Tiny hygrobots need no batteries—they are powered by water
A team of researchers at Seoul National University has developed a series of small robots that move without need for an engine or batteries. Instead, as the researchers explain in their paper published in the journal Science Robots, the hygrobots, as they are called, move due to absorption and evaporation of water.
Movement of the hygrobots also called for controlling the environment to some extent—in some instances, the team quickly cycled the air in which the hygrobots operated between moist and dry. But they also found that using just the right mix of nanofibers in a dry environment allowed for creating a hygrobot capable of traveling across a wet surface using only the natural differences in humidity levels.
The team videotaped several of their creations in action, such as an inchworm-type bot making its way across a surface and a bot slithering like a sand snake across another surface. And in one instance, a smaller form of their inch-worm-like hygrobot moving across a petri-dish carrying with it antibiotics that cut across a bacterial biofilm. The group suggests their tiny bots might one day prove useful in military applications, as well—and perhaps as medical treatments, or as bots able to deliver drugs inside the body.