No matter how long you make a wire, it never seems to be long enough. Whether used for headphones, charging phones or plugging in equipment, it seems like a cord can always be longer. Researchers from the University of North Carolina may have solved the problem once and for all. They have created conductive wires that can stretch up to eight times their original length and still function. The researchers create the wires with a thin tube made of an elastic polymer, then fill it with a metal alloy of gallium and indium—efficient conductors of electricity.

“Previous efforts to create stretchable wires focus on embedding metals or other electrical conductors in elastic polymers, but that creates a trade-off,” said Michael Dickey, an assistant professor of chemical and bio-molecular engineering at North Carolina State and co-author of a paper on the research. “Increasing the amount of metal improves the conductivity of the composite, but diminishes its elasticity.”

“Our approach keeps the materials separate, so you have maximum conductivity without impairing elasticity. In short, our wires are orders of magnitude more stretchable than the most conductive wires, and at least an order of magnitude more conductive than the most stretchable wires currently in the literature.”

According to Dickey, the manufacturing of the wires is a relatively straightforward process, but researchers still have to overcome one problem before the products can be rolled out to the public: minimizing leakage of the metal if the wires become severed.

[Image via North Carolina State University]