The durable soft electronics could be used in wearable electronics and soft robotics and could someday be part of a stretchable smartphone.
Skin-like electronic circuits are soft and stretchy, sustain numerous damage events under load without losing electrical conductivity, and can be recycled to generate new circuits at the end of a product’s life. Current consumer devices, such as phones and laptops, contain rigid materials that use soldered wires running throughout. The new circuits replace these inflexible materials with soft electronic composites and tiny, electricity-conducting liquid metal droplets that are initially dispersed in an elastomer — a type of rubbery polymer — as electrically insulated discrete drops. To make the circuits, the researchers introduced a scalable approach through embossing, which allows them to rapidly create tunable circuits by selectively connecting droplets. If a hole is punched in the circuits, the metal droplets can still transfer power. Instead of cutting the connection completely as in the case of a traditional wire, the droplets make new connections around the hole to continue passing electricity. The circuits will also stretch without losing their electrical connection, as the team pulled the device to more than 10 times its original length without failure.
Virginia Tech, Blacksburg, Virginia
The soft electronics are part of a rapidly emerging field that gives gadgets a level of durability that would have been impossible just a few years ago. At the end of a gadget’s life, the metal droplets and the rubbery materials can be reprocessed and returned to a liquid solution, effectively making them recyclable.
While a stretchy smartphone has not yet been made, rapid development in the field also holds promise for wearable electronics and soft robotics. The team is making progress and envisions these materials as key components for soft circuitry that could survive in a variety of real-world applications.