Most materials used in electronic circuitry tend to be rigid. Engineers have tried to force them into stretchability by fashioning them into smaller and smaller accordion-like mechanisms, yielding circuits with bendable joints. Those joints fail over time, however, as they concentrate the energies of wear. To solve the problem, researchers at North Carolina State University and the University of Michigan turned away from the accordion to another flexible, toylike model: the Slinky. (To be fair, the abstract doesn’t mention the Slinky. But it is a good example of a stretchable structure made from rigid material by using coils.)
The team created spiraling silicon nanowires by fabricating them on a stretched rubber substrate; when the stretch was released, the nanowires sprang into coils. (It sounds simpler than it was; to stretch the rubber substrate to precise specs, the researchers applied measured amounts of ozone and ultraviolet light.) The resulting coiled nanowires stretch to more than twice their resting length. Once the electronics are figured out, engineers will be on their way to creating stretchy circuits that can be embedded in textiles or implanted in medical devices. I worry about the durability of such circuits, however; every Slinky I ever owned ended up lying in a tangled knot at the bottom of the toy chest. �via Eurekalert