Graphene enhanced flexible piezoelectric transducers for dynamic strain measurement: from material preparation to application


 In this study, graphene particles are introduced to the lead magnesium niobate-lead titanate (PMN-PT) and polyvinylidene fluoride (PVDF) to form a flexible ternary composite. The graphene concentration is rigorously designed and morphologically optimized, warranting good piezoelectric and dielectric properties. The piezoelectric and dielectric performances are greatly increased compared with the pure PVDF films. Then a theoretical model is formulated to quantitatively interpret the graphene effect on the permittivity performance and to provide guidelines for the optimization of graphene volume fraction. Moreover, a simple and cost-effective technique is designed to package the composite film as a large-area, lightweight and flexible transducer. Several confirmatory experiments and a proof-of-concept test are performed based on the proposed flexible piezoelectric transducers to validate the capability of the dynamic strain sensing. By comparing with the results from conventional strain gauges and ceramic piezoelectric wafers, it is verified that the proposed flexible transducer has proven responsivity and precision in responding to quasi-static strain, medium-frequency vibration, and ultrasound. The great potential of the developed transducer for a wide range of applications including structural health monitoring and human motion detection has been demonstrated.