A high- sensitivity wearable flexible strain sensor based on three-dimensional twist-like network structure

With the rapid development of the flexible electronics field, flexible pressure sensors are widely used inwearable devices, medical monitoring and other fields. However, it is still a huge challenge to design a sensor with highsensitivity, low cost and a simple manufacturing process. In this work, we report a flexible strain sensor based on discarded mask straps (MS) with a unique three-dimensional (3D) twist-like network structure. Multi-walled carbon nanotubes (MWCNTs)/carbon nanoparticles (CN)/MS composites were prepared by a simple dip-drying method and encapsulated using a medical Polyurethane (PU) film. It is founded that the fabricated MWCNTs/CN/MS/PU flexible strain sensor (MCMP-FSS) exhibits a high gauge factor (GF) of 13,928 and advanced performance with a large sensing range of 0%-72%. Moreover, good water-repellent harmony and various types of stimuli over 1000 cycles were obtained for the MCMP-FSS. Benefiting from the unique 3D twist-like network structure and the MWCNTs/CN synergistic conductive network, MCMP-FSS also has broad application prospects in the fields of human motion detection, encrypted communication, and natural human-robot interaction.