Super elastic 'skin' for softer, mood robots

Imagine a "doctor" robot that could display the patient's temperature and pulse and even reacts to a patient's mood. Now, Cornell University researchers have developed an electroluminescent "skin" that stretches to more than six times its original size while still emitting light.

The discovery can lead to significant advances in health care, transportation, electronic communication and other areas.

"This material can stretch with the body of a soft robot. It allows robots to change their colour and it also allows displays to change their shape," said Rob Shepherd, assistant professor of mechanical and aerospace engineering.

This hyper-elastic light-emitting capacitor (HLEC) can endure more than twice the strain of previously tested stretchable displays.

It consists of layers of transparent hydrogel electrodes sandwiching an insulating elastomer sheet. The elastomer changes luminance and capacitance (the ability to store an electrical charge) when stretched, rolled and otherwise deformed.

"We can take these pixels that change colour and put them on these robots, and now we have the ability to change their colour," Shepherd added in a paper published in the journal Science.

In addition to its ability to emit light under a strain of greater than 480 percent its original size, the group's HLEC was shown to be capable of being integrated into a soft robotic system.

Three six-layer HLEC panels were bound together to form a crawling soft robot, with the top four layers making up the light-up skin and the bottom two the pneumatic actuators.

The chambers were alternately inflated and deflated, with the resulting curvature creating an undulating, "walking" motion.