A Weavable, Wrinkle-Textured TPU/PDA/Ag Fiber-Based Strain Sensor Fabricated by Wet-Spinning and Electroless Plating

With diversified global healthcare development and increasingly prominent population aging, smart wearable electronic systems have emerged as a crucial approach to address personalized health monitoring demands and enhance life quality. Currently, fiber-based strain sensors face common challenges, including limited sensitivity, insufficient mechanical flexibility, and poor weavability, which significantly hinder their practical applications in intelligent healthcare fields. In this study, thermoplastic polyurethane (TPU) fibers were first fabricated via wet-spinning technology and then immersed in an N,N-dimethylformamide (DMF) solution to create wrinkled surface structures. Subsequently, TPU/PDA/Ag composite fibers were successfully made by electroless silver plating. The silver layer established a highly conductive network, while the composite fibers demonstrated customizable configurations through weaving and excellent comfort, flexibility, and weavability. Experimental results revealed that the TPU/PDA/Ag composite fibers exhibited high sensitivity (GF = 1812.8), excellent tensile properties (328.2% strain), broad sensing range (1–100%), rapid response time (88 ms), and outstanding cyclic stability (3000 stretching cycles). Notably, these fibers can detect both gross limb movements (wrist, elbow, knee, and ankle) and subtle facial expressions. Furthermore, fiber-based sensors woven with pure TPU fibers as warp and interwoven with as-prepared fibers as weft demonstrate the capability of recognizing basic hand gestures through finger sheath integration, showing promising potential for intelligent flexible wearable devices.