Things like earbud cords have a nasty way of getting hooked on things and breaking. Such incidences may become a lot less common, however, as scientists from North Carolina State University have created conductive wires that stay intact even when stretched up to eight times their regular length.

The researchers made the wires by filling a tube of extremely elastic polymer with a liquid metal alloy of gallium and indium. As a result, even when the polymer is stretched to several times its relaxed state, the liquid metal inside of it is still able to carry an electrical current. A demonstration can be seen in the video below.

According to NC State’s Dr. Michael Dickey, other efforts at creating stretchable electrical wires have involved embedding metals or other conductive materials within the polymer matrix itself. Doing so, however, compromised the elasticity of the material.

“Our approach keeps the materials separate, so you have maximum conductivity without impairing elasticity,” he said. “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.”

Not only could the wires be useful in devices like earbuds or phone chargers, but they could also find use in smart fabrics or stretchable electronics. Some of NC State’s other approaches to routing electricity through such materials have involved the use of coiled nanowires or carbon nanotubes that straighten out as the material stretches.

Before the new wires make their way into anything, however, the scientists still need to figure out how to minimize leakage of the liquid metal should the polymer be damaged.

Scientists from Northwestern University are conducting similar research – they’ve developed a stretchable electronic material in which liquid metal is deposited within the pores of an elastic polymer.