Spatially Programmable Electromechanical Response Enabled by Designed Island-Bridge Conductive Fibers for Motion-Sensing Textiles

Integrating high conductivity, stretchability, and mechanical and electrical performance in fibers remains challenging for wearables. This study develops highly stretchable, recyclable composite conductive fibers with exceptional electromechanical stability. Fibers were fabricated via wet-spinning by uniformly dispersing liquid metal particles (LMPs) and carboxylated carbon nanotubes (CNT-COOH) within a polyurethane matrix, forming an initial LMP-CNT_Net island-bridge network. Subsequent ultrasound activation induced the assembly of a continuous LMP-dominated network (LMP_Net), creating a hierarchical dual-network structure (LMP_Net-CNT_Net). This design achieves a conductivity of 3.22 × 10³ S·m^-1, a tensile strength of 6.6 MPa, strain-insensitive charge transport (Δ<i>R</i> < 1.3 Ω·cm^-1 at 100% strain), and near-zero resistance drift (1.6% change over 2000 cycles). Programmatic modulation of the fiber spatial structure via ultrasonic activation enables the integration of high-power transmission, precision Joule heating, and real-time motion sensing. Moreover, the system enables closed-loop recycling via dissolution/respinning, retaining >80% original performance after five cycles. This work provides a sustainable and robust platform for next-generation multimodal smart textiles.