Highly stretchable and elastic PEDOT:PSS helix fibers enabled wearable sensors

Wearable electronics have emerged as a promising research field, generating considerable interest in exploring the high stretchability and electrical sensitivity of flexible conducting materials. This work proposes a novel, eco-friendly technique to continuously produce self-helical conductive PEDOT:PSS fibers. The resultant fibers reveal a high breaking tensile elongation (>950%), superior electrical conductivity (650 S cm−1), and remarkable elasticity even when deformed by up to 400%. The morphology and performance of self-helical fibers can be optimized by tuning the metal salt concentrations in the coagulation bath, spinning speeds, and needle inner diameter. Additionally, finite element software (Ansys) was used to model the fibers under stress. The optimal fibers spun from the coagulation bath made of 20 vol% phosphoric acid aqueous solution with 0.05 M magnesium chloride were selected as a sensing unit. These fibers possess excellent sensitivity and cycle stability over a broad range of operations, making them suitable for accessible human–computer interfaces and next-generation flexible electronics.