Ultra-highly sensitive graphene/polyaniline@epoxidized natural rubber strain sensors for human motion monitoring

Flexible strain sensors are one of the core devices in wearable electronics . At present, it is still difficult to develop flexible strain sensors with high stretchability, sensitivity, and long-term stability. In this work, polyaniline (PANI) was coated on the surface of epoxidized natural rubber (ENR) nanospheres to obtain the PANI@ENR nanospheres, and then mechanically blended with graphene (GN) sheets to prepare the GN/PANI@ENR composites. The composite conductive networks composed of PANI and GN endow the composites with excellent mechanical, electromechanical and strain-sensing performances. The strain-sensing tests show that the ENR composites possess an ultra-high gauge factor (GF) of 29671.7 within 270% of strain. Meanwhile the composites exhibit excellent cycling stability of over 2500 cycles. In addition, the GN/PANI@ENR strain sensors can monitor the large-strain (finger, wrist, elbow and knee joints bending) and small-strain (strains of vocal cord vibration, pulse, facial muscle movements) motions of the human body in real time, indicating a wide range of potential applications in wearable flexible electronics.