Abstract
Conductors that can sustain large strains without change in resistance are highly needed for wearable electronic systems. Here, the fabrication of highly stretchable coaxial fiber conductors through self-buckling of conductive polymer ribbons inside thermoplastic elastomer channels, using a "solution stretching-drying-buckling" process, is reported. The unique hierarchically buckled and conductive core in the axial direction makes the resistance of the fiber very stable, with less than 4% change when applying as much as 680% strain. These fibers can then be directly used as stretchable electrical interconnects or wearable heaters.