Recent developments in bio-monitoring via advanced polymer nanocomposite-based wearable strain sensors

Recent years, an explosive growth of wearable technology has been witnessed. A highly stretchable and sensitive wearable strain sensor which can monitor motions is in great demand in various fields such as healthcare, robotic systems, prosthetics, visual realities, professional sports, entertainments, etc. An ideal strain sensor should be highly stretchable, sensitive, and robust enough for long-term use without degradation in performance. This review focuses on recent advances in polymer nanocomposite based wearable strain sensors. With the merits of highly stretchable polymeric matrix and excellent electrical conductivity of nanomaterials, polymer nanocomposite based strain sensors are successfully developed with superior performance. Unlike conventional strain gauge, new sensing mechanisms include disconnection, crack propagation, and tunneling effects leading to drastically resistance change play an important role. A rational choice of materials selection and structure design are required to achieve high sensitivity and stretchability. Lastly, prospects and challenges are discussed for future polymer nanocomposite based wearable strain sensor and their potential applications.