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. |