Mechanically Robust, Highly Sensitive and Superior Cycling Performance Nanocomposite Strain Sensors Using 3-nm Thick Graphene Platelets

Abstract Flexible, highly sensitive stain sensors combining polymers with nanofillers have attracted a great deal of interests, due to the rapid development of robotics, transportation, aerospace and health monitoring. However, these sensors are often limited by unideal mechanical properties, sensitivity and cycling performance. We herein report a facile approach to developing high-cycling performance strain sensors based on a nanocomposite film. The film was prepared by dispersing 3 nm-thick graphene platelets (GnPs) within an epoxy matrix. TEM micrographs confirmed that GnPs were uniformly dispersed in epoxy and some were closely connected to each other, which improved the mechanical properties and electrical conductivity of the resulting nanocomposites. At 2 vol% GnPs, Young’s modulus, fracture toughness and energy release rate of neat epoxy were improved by 93%, 135% and 215%, respectively. Having gauge factors of 1–33, the film sensor demonstrated high sensitivity to tensile strains of 0–0.67%. Meanwhile, the film sensor revealed excellent cycling performance over 35,000 cycles due to effective dissipation of the heat accumulated during fatigue cycles. Practically, the film sensor also demonstrated effective response to temperature, humidity and damage evolution. This work provides an effective strategy for developing graphene-based strain sensors for excellent mechanical properties, sensitivity and reliability.