Highly stretchable and sensitive sensor based on GnPs/EPDM composites with excellent heat dissipation performance

Abstract

A highly stretchable, flexible, and sensitive strain sensor is fabricated based on the graphene platelets (GnPs) and ethylene propylene diene monomer (EPDM). Owing to the better dispersion of GnPs in EPDM material, the sensor obtains low percolation threshold of 2.9 wt% and superior thermal conductivity of 0.72 W/m K at 7 wt%. In this paper, GnPs/EPDM composites with GnPs loading of 3 wt% and 5 wt% were selected as strain sensor, and were tested via various mechanical tests. The monotonic tensile results reveal that the sensor with GnPs loading of 3 wt% exhibits relatively high gauge factor of 129.33. The linear growth of the electrical response is softened at 5 wt% GnPs and there were two different linear change sensing stages (0–210%) and (210–300%), and the gauge factors were 52.76 and 107.99, respectively. The sensor with GnPs loading of 3 wt% is reversibility upon 36-cycle loading–unloading test, and can be used as a health-monitoring device by detecting bending of elbow and finger. The result shows that the sensor has higher sensitivities. Furthermore, the mechanism behind the excellent performances of GnPs/EPDM sensor is discussed. The high-performance GnPs/EPDM sensor shows great potentials in the field of monitoring deformation and human body’s motions.