Researchers at Virginia Tech University have developed a new type of soft electronics that can self-heal and be recycled at end of life.
The ‘skin-like’ circuits, developed at the university’s Department of Mechanical Engineering and Macromolecules Innovation Institute, aim to pave the way for a new generation of reconfigurable, robust self-healing devices.
Led by assistant professor Michael Bartlett, the team’s approach replaces rigid materials and soldered wires currently used in consumer electronics with soft electronic composites and tiny electricity-conducting liquid metal droplets. The result is said to be a soft and stretchy circuit that can sustain ‘numerous damage events’ under load without losing conductivity.
Published in Communications Materials, the team’s study describes how the liquid metal droplets were initially dispersed in an elastomer, a type of rubbery polymer, as electrically insulated, discrete drops.
“To make circuits, we introduced a scalable approach through embossing, which allows us to rapidly create tuneable circuits by selectively connecting droplets,’ said postdoctoral researcher and first author Ravi Tutika. “We can then locally break the droplets apart to remake circuits and can even completely dissolve the circuits to break all the connections to recycle the materials, then start back at the beginning.”
If a hole is punched in the circuits, the metal droplets can still transfer power, researchers said, by making new connections around the hole to continue conducting electricity. The team also reported stretching the device to over ten times its original length without loss of electrical connection.
At the end of a product’s life, the metal droplets and rubbery materials can be reprocessed and returned to a liquid solution. They can then be remade, offering potential for sustainable, recyclable electronics.
Researchers believe that the development holds promise for wearable electronics and soft robotics amongst other emerging soft technologies.