Conductive chromotropic fiber filament sensors with ultrahigh stretchability for wearable sensing textiles toward 3D optical motion capture

Abstract

Wearable strain sensors have received increasing attention on account of their exciting applications in monitoring human movements. However, such conventional devices face the dilemma of low stretchability and inefficient 3D spatio-temporal motion detection. Here, novel Joule-thermochromic Ecoflex fiber filaments with ultrahigh stretchability are fabricated at the meter-scale via an improved wet-spinning technique, which exhibit fascinating properties including a wide sensing range (up to 210%), high sensitivity (gauge factor of 61 within strain 100–200%), fast resistance response time (≈58 ms) and broad color range from pink to blue to purple in the range of the 20–30 °C gradient. Importantly, the chromotropic sensing properties remain basically unchanged after 3000 stretching (50%) cycles and 3 h of machine washing. By integrating an optical motion capture system with the thermochromic fiber filament based fabric sensors, computer vision technology can be used to mark the target, calibrate the contour and make data statistics based on the color change for detecting the 3D pathway of human movements in real time. This work provides a new route for developing stretchable chromotropic strain sensors that can track the 3D spatial–temporal motion of humans.