Researchers Create Ultrastretchable Wires Using Liquid Metal

"From TFA, the changing cross srction reduces resistance as it stretches.... they could be designed for no change when stretched"

Well, that's not quite what TFA writes: "As expected, electrical measurements show that the fibers increase resistance as the fiber elongates and the cross sectional area narrows. Fibers with large diameters (~600 [micrometers]) change from a triangular to a more circular cross-section during stretching, which has the appeal of lowering the resistance below that predicted by theory."

The abstract doesn't mention how the circular/triangular transition would affect the resistance - with conservation of volume it shouldn't matter. But I don't read here in any way that this effect would be able to cancel the resistance increase due to stretching.

Note that in first approximation, resistance would scale as L^2 for a wire with length L (both diameter decrease and length increase affect the resistance). With stretching up to a factor 10, i.e. 100x increase in resistance, a small effect due to the shape of the cross section would be negligible.

Source: http://rss.slashdot.org/~r/Slashdot/slashdotScience/~3/lXrmIxZz4AA/story01.htm

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