Even in this age of smartphones and other electronics wonders, these ideas sound quite futuristic. But 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. The discovery could lead to significant advances in health care, transportation, electronic communication and other areas.
This hyper-elastic light-emitting capacitor (HLEC), which can endure more than twice the strain of previously tested stretchable displays, consists of layers of transparent hydrogel electrodes sandwiching a dielectric (insulating) elastomer sheet. The elastomer changes luminance and capacitance (the ability to store an electrical charge) when stretched, rolled and otherwise deformed.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.
Although Shepherd admitted to “not being very fashion-forward,” another application involves wearable electronics. While wearable technology today involves putting hard electronics onto a soft base (think Apple Watch or Fitbit), this discovery paves the way for devices that fully conform to the wearer’s shape.
The Shepherd Group has also developed a lightweight, stretchable material with the consistency of memory foam, with the potential for use in prosthetic body parts, artificial organs and soft robotics.
The group’s latest work was supported by a grant from the Army Research Office, a 2015 award from the Air Force Office of Scientific Research, and two grants from the National Science Foundation.
