Strain-Insensitive Stretchable Conductive Fiber Based on Helical Core with Double-Network Hydrogel

The development of the highly stretchable and strain-insensitive conductive fibers exhibiting extremely small resistance change under large deformation is crucial for the electronic signal stability in the smart wearable fields. In this paper, an all-polymeric conductive microfiber (PU@PVA-PEDOT:PSS SI-CF) with desirable performances has been developed by using microfluidic spinning technology (MST), during which process the instinct strain-insensitive conductive polymer hydrogel core with semi-interpenetrating network is constructed into the helical structure. The configuration and performances of the PU@PVA-PEDOT:PSS SI-CF have been optimized by regulating the processing parameters of MST, and the fabricated microfiber exhibits excellent stretchability (up to 500%), high conductivity (147 S cm⁻¹), super conductance strain insensitivity (ultra-low resistance change of 5% at 100% strain), as well as excellent durability (2000 stretching-releasing cycles). The PU@PVA-PEDOT:PSS SI-CF shows great smart wearable application potential as the stretchable wire, the self-powered sensor, and the electro-thermal heater.