Scalable wet-spun stretchable conductive fibers with SWCNT-enhanced mechanical and electrical properties for multifunctional wearables

Stretchable conductive fibers demonstrate considerable potential in various wearable flexible devices. However, the scalable fabrication of stretchable conductive fibers that combine ultrahigh stretchability with excellent electrical conductivity remains a significant challenge. Here, we report a simple and scalable wet-spinning strategy to prepare continuous multifunctional pre-vulcanized natural rubber (NR) latex (PNRL)/single-walled carbon nanotubes (SWCNT) composite fibers. The effects of SWCNT microstructure and doping ratio on the mechanical and electrical properties of the composite fibers are systematically investigated. Remarkably, with only 1 wt% SWCNT, the composite fibers achieve a tensile strength of 28.46 ± 1.41 MPa, a strain at break of up to 900 ± 70 %, and an electrical conductivity of 0.297 ± 0.09 S·m −1 . In-situ X-ray scattering characterization revealed that SWCNTs facilitate strain-induced crystallization of NR, acting as nucleation sites that promote the stretch-induced alignment of NR chains, leading to a significant enhancement in the mechanical properties of the PNRL/SWCNT composite fibers. These fibers demonstrate excellent multifunctionality and practical applicability as strain sensors and solar-heating fabrics. This study not only offers a scalable route to high-performance stretchable conductive fibers, but also provides valuable insights into the design principles for optimizing nanocomposite fiber properties.