Waterproof and conductive tough fibers for washable e-textile

Abstract Conductive fibers are essential for wearable electronics, especially in electronic textiles (e-textiles) used as skin-interfaced sensors and interconnects. Achieving sustainable e-textiles with integrated toughness, waterproofing, and washability remains challenging. We present waterproof conductive tough fibers (CTFs) fabricated via a scalable, continuous capillary tube-assisted coating (CTAC) process. The multilayered CTFs demonstrate a conductivity of 6.42 kS/cm, Young’s modulus of 6.22 MPa, toughness of 9.40 × 10 5 J/m 3 , and 70% strain at break. With lengths exceeding 20 m, a native oxide layer on the eutectic gallium-indium (EGaIn) shell ensures reliable waterproofing with the IPX8 standard. They also maintain consistent performance for 24 days water immersion and repeated washing up to 100 cycles, showing superior resistance retention compared to the EGaIn-absence fibers. As a proof-of-concept, they enable wireless power transfer and reliable monitoring of electrocardiogram and electromyogram signals, establishing a robust platform for sustainable e-textiles.