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 a fast and reliable feedback of the human motion, even for fine gesture, and can detect vital physiological parameters such as breathing and heart beating, while being able to be easily integrated on 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 pre-conditioning for strain up to 20%. Together with a measured gauge factor of about 10, sensors without pre-conditioning exhibits very good stability and they result to be a good candidate for wearable applications. We demonstrate this statement analyzing the performance of a smart wristband prototype that integrates these strain gauges, obtaining very high performance of the sensors without pre-strain in gesture recognition tasks with an accuracy and F-score of about 94%.