Soft robots can bend, walk and grip, but unlike their rigid counterparts, they can deform and bounce back into shape. In their recent publication in the journal ACS: Applied Materials & Interfaces, graduate student Gregory Gossweiler and MRSEC investigator Stephen Craig report a new way to make an elastic material for soft robots that changes color when it stretches. The color change might be used as camouflage or to indicate stress points, leading to a better robot design, but it also shows that the team has the capability to embed other chemical agents in the polymer that might be released on command, such as drugs, catalysts or enzymes.
Flexible, elastic, and soft robots under development could bridge the gap between traditional rigid robot movements and the more fluid, adaptable movements of animals and humans. These soft machines respond when they are pumped with gases or liquids. This inflation results in specific shape changes and desired movements. To impart more versatility to these devices, Stephen 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 allow a robot to camouflage itself while 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.
Watch the robots walk and grip here.