Researchers at the North Carolina State University have created conductive wires that are made out of liquid metal, with the ability to stretch eight times their original length, without compromising their basic functionality. These wires could be used in headphones as well as phone chargers.
The scientists published their findings in the journal Advanced Functional Materials. The wires were made with a thin tube of an elastic polymer that was filled with a liquid metal alloy of gallium and indium, which conducts electricity efficiently.
Previous efforts to create stretchable wires focused on embedding materials or other electrical conductors in elastic polymers, creating a trade-off, states Michael Dickey, a chemical engineer at NC State, and co-author of the paper.
Increasing the amount of metal improves the conductivity of the composite, but diminishes its elasticity, Dickey continues. The approach was to keep the metals separate, so that there is maximum conductivity without impairing elasticity. The wires are orders of magnitude more stretchable than most conductive wires, and at least an order of magnitude more conductive than most of the stretchable wires currently in the scientific literature.
The manufacturing process of these new wires is relatively straightforward, but before any commercial applications are started, the scientists need to figure out how to minimize the leakage of the material if the wires are severed.
Reference: “Ultrastretchable Fibers with Metallic Conductivity Using a Liquid Metal Alloy Core” by Shu Zhu, Ju-Hee So, Robin Mays, Sharvil Desai, William R. Barnes, Behnam Pourdeyhimi and Michael D. Dickey, 13 December 2012, Advanced Functional Materials.
DOI: 10.1002/adfm.201202405
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1 Comment
Liquid gallium alloys cause the catastrophic disintegration of things made of aluminum. So dangerous is this effect- a single drop of the molten metal can turn a high strength aluminum girder to mush, that air shipment of gallium is essentialy forbidden.
Heaven help the rider whose bike frame runs afoul of this stretch earbuds!