All-Textile Wearable Capacitive Pressure Sensors Based on Cut-Pile Fabrics with Integrated Electrodes

Wearable pressure sensors have the potential to revolutionize healthcare and promote wellness through the detection and monitoring of vital signs and human motion. Although textiles are an ideal platform for wearable sensors due to their ubiquity in daily life, textile-based pressure sensors typically suffer from low sensitivity. Capacitive pressure sensors require a porous, deformable dielectric layer to achieve high sensitivity, and off-the-shelf textiles have not met this challenge. In this paper, we present all-textile capacitive pressure sensors based on off-the-shelf cut-pile fabrics, in which we use selective solution metallization to integrate the electrode and cut-pile dielectric layer into a single piece of fabric. The resulting sensors exhibit sensitivities (0.029 kPa^-1) and response times (3 ms) suitable for monitoring motions of the human body. We demonstrate their utility to detect subtle human facial motions, as well as grip strength. Through a comparative analysis of different cut-pile fabrics, we show that the compressibility of the cut-pile layer and thus the sensitivity of the sensor depend on the specific attributes of the cut piles. This work provides not only a new approach to wearable textile-based sensor fabrication but also insight into the textile structure/performance relationships necessary to advance the field of e-textiles.