Application of Unconditioned Nanostructured Thermoplastic-Based Strain Gauge Sensor in Wearable Electronics

Wearable electronics is now revolutionizing the world of smart sensors offering tremendous solutions to a variety of applications that span from biomedical market to gaming and fashion sectors. In this scenario, physical sensors play a crucial role since they offer fast and reliable feedback on human motion, even for fine gestures, and can detect vital physiological parameters such as breathing and heart beating, while being able to be easily integrated into textile. Among wearable physical sensors, thermoplastic materials are utilized for their sensitivity and high stretchability. Moreover, these materials exhibit a good chemical resistance and implement low-cost manufacturing processes. In this work, we report a full characterization of a new thermoplastic nanocomposite material comparing its performances with and without preconditioning for strain up to 20%. Together with a measured gauge factor (GF) of about 10, sensors without preconditioning exhibit very good stability and they result to be a good candidate for wearable applications. We demonstrate this statement by analyzing the performance of a smart wristband prototype that integrates these strain gauges, obtaining very high performance of the sensors without prestrain in gesture recognition tasks with an accuracy and F-score of about 94%.