Printable wet-resistive textile strain sensors using bead-blended composite ink for robustly integrative wearable electronics

With an increased demand for integrative wearable devices for various smart healthcare systems, highly deformable textile strain sensors have attracted significant attention in recent years. For real application as wearable devices, the primary challenge is developing outperforming textile strain sensors with mechanical robustness and high operational stability under both dry and wet conditions. Here a printable micro-structured textile strain sensor with high sensitivity and mechanical durability is proposed for these integrative wearable devices. A composite ink, composed of a conductive mixture with elastic microbeads and conducting polymer, is incorporated into the sensor via a simple printing process. These conducting polymer-encapsulated elastic microbeads provide a microcrack structure on the textile strain sensor, yielding sensitivity with a maximum gauge factor of 57. The conformally printed textile strain sensor allows integrative devices to retain their high sensing performances with a wide sensing range (~130%), excellent repeatability (>10,000 cycles), and waterproof capability (contact angle ~112°). To demonstrate its high versatility in practical application, the printable textile strain sensor is applied to an integrative user-interface device, monitoring respiration and arm motion signals in real time under both dry and wet environments.