Dip-Coated Conductive\nPolyurethane Fibers Composited\nwith Liquid Metal Particles and Multiwall Carbon Nanotubes for Multifunctional\nApplications

Currently, highly stretchable conductive fibers have\nbecome one\nof the most important components of flexible electronics due to their\nexcellent conductivity, adaptability, and knittability. In this work,\na conductive fiber was developed with a thermoplastic polyurethane\n(TPU) core and a composited conductive sheath of liquid metal particles\n(LMP) and multiwall carbon nanotubes (CNTs) by simply dip coating\nand then was permeated and encapsulated by a waterborne polyurethane\n(WPU) layer. After mechanical sintering, the resulting WPU/LMP-CNTs/TPU\nfiber (WLCTF) exhibited ultrahigh conductivity, reaching 1.15 ×\n10<sup>6</sup> S/m, along with remarkable linearity (<i>R</i><sup>2</sup> = 0.997) across a large strain range of 160%. The WLCTF\nwas molded by thermoplastic process into stretchable helical electrodes,\nwhich provided a stable signal output at 1700% strain with an extremely\nhigh-quality factor of 5483.9 (helical index of 7). Notably, these\nfibers can be woven into fabric substrates to possess Joule heating\ncapabilities and waterproof properties; in addition, the WLCTF is\nengineered with efficiency in recycling. With its consistent strain\nsensing capabilities, electrical conductivity, recyclability, and\nJoule heating properties, the WLCTF holds significant potential for\nadvancement in the fields of flexible electronics and wearable technology.