An electroluminescent display made with the new stretchy skin. Photo: Science, Organic Robotics Lab at Cornell University.
An electroluminescent display made with the new stretchy skin. Photo: Science, Organic Robotics Lab at Cornell University.

A team of Cornell graduate students – led by Rob Shepherd, assistant professor of mechanical and aerospace engineering – has developed an electroluminescent ‘skin’ that stretches to more than six times its original size while still emitting light. This discovery could lead to significant advances in healthcare, transportation, electronic communication and other areas, with possible applications including a healthcare robot able to display a patient's temperature and pulse, and even react to their mood.

"This material can stretch with the body of a soft robot, and that's what our group does," Shepherd said, noting that the material has two key properties: "It allows robots to change their color, and it also allows displays to change their shape."

As reported in Science, the skin, or 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 or otherwise deformed.

"We can take these pixels that change color and put them on these robots, and now we have the ability to change their color," Shepherd said. "Why is that important? For one thing, when robots become more and more a part of our lives, the ability for them to have emotional connection with us will be important. So to be able to change their color in response to mood or the tone of the room we believe is going to be important for human-robot interactions."

In addition to being able to emit light under when stretched to more than 480% its original size, the group's HLEC was also 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 panels forming the light-up skin and the bottom two the pneumatic actuators. These bottom two panels were alternately inflated and deflated, with the resulting curvature creating an undulating ‘walking’ motion.

This story is adapted from material from Cornell University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.