Fully-integrated wearable pressure sensor array enabled by highly sensitive textile-based capacitive ionotronic devices

Recently, textile-based pressure sensors have gained considerable interest in the field of wearable electronics due to their wide range of applicability and good scalability. Despite recent progress, however, urgent challenges remain to develop a fully integrated textile sensor array with highly sensitive multi-sensing capability and low-power consumption. Here, we demonstrate a highly-sensitive capacitive ionotronic (CIT) pressure sensor array using high-k ion-gel (IG) film for implementation of textile-based electronic systems. With a composition and thickness optimized IG film, CIT pressure sensors with high sensitivity up to 308 nF kPa−1 and relatively good stability was successfully obtained. In addition, based on mechanical simulations using finite element method, it was found that the pressure-dependent contact-area variation between multifilament fiber electrodes and the IG film played the dominant role in capacitance change rather than the thickness change of the IG film. Furthermore, a 3 × 3 CIT pressure sensor system is implemented on a large-area textile substance with multi-point detection capability, demonstrating a textile-based pressure monitoring system integrated with a pressure variable multi-color light emitting diode array.