Soft robots can bend, walk and grip. And, unlike their rigid counterparts, some can get flattened and bounce back into shape. Now scientists report a new advance in the journal ACS Applied Materials & Interfaces: a way to make elastic material for soft robots that changes color when it stretches. They say this process opens the door to robot camouflage, new ways to deliver medicines and other applications.
Most commercial robots are stiff, made of hard plastics and metal parts. But the supple robots under development could bridge the gap between today’s inflexible varieties and the more fluid and forgiving movements of animals and humans. These machines work when operators pump them with gases or liquids. This inflation results in specific shape changes and desired movements. To impart more versatility to the devices, Stephen L. Craig and colleagues wanted to take advantage of the molecular changes that occur when a robot curls or twists.
The researchers incorporated color-changing compounds in their robots’ material that are activated when stretched. This feature could help a robot camouflage itself when it moves. And, because the color change is most intense where the strain on the material is highest, it also can indicate where it’s vulnerable to breaking. The researchers note that other compounds could also be added to release drug molecules, make a robot glow or repair the material when it ruptures.