A sensitive and flexible interdigitated capacitive strain gauge based on carbon nanofiber/PANI/silicone rubber nanocomposite for body motion monitoring

Abstract

Stretchable nanocomposites-based strain gauges have received much attention due to their adjustable properties in various applications, including soft robotics, human health monitoring, body motion detection, structural health monitoring, and artificial intelligence. Although low sensitivity (gauge factor) is one of the challenges of capacitive strain gauges, in this study, we design, manufacture, and illustrate characterizations of a stretchable interdigitated capacitive strain gauge based on carbon nanofiber/polyaniline/silicone rubber nanocomposite by an improvement in sensitivity with linearity, and low hysteresis. This strain gauge reaches a gauge factor of about 14 over an applied strain of 2% and about 2.8 over an applied strain of 20% and demonstrates linearity with negligible hysteresis. The sensitivity of the strain sensor is enhanced not only by the interdigitated design of electrodes but also by the electrodes' outstanding electrical conductivity, even in a large strain. Due to its sensitivity, the proposed device is suitable for detecting small and large strains and can be used in wearable applications or straight on the skin for human motion detection.