Facile fabrication of covalently grafted functionalized graphene-PVDF composites as strain sensor with tunable sensitivity: Application to the structural health and human motion monitoring

Abstract

The rapid development of smart strain sensors has contributed enormously in the field of building construction, physiological health monitoring, soft robotics and wearable devices with the accelerating proliferation of smart electronics. However, the low stretchability and sensitivity of conventional metals or inorganic semiconductor-based piezoresistive sensors have severely restricted their applications in this field. Herein, facile and efficient fabrication of 1-(3-aminopropyl) imidazole functionalized rGO-PVDF composites was introduced for the applications ranging from drastic to subtle deformation monitoring. This article focused into the potential uses of strain sensors and elaborated their diverse applications in various disciplines. Structural constitution and multilayered structure of piezoresistive sensors exhibited substantial electrical conductivity, linearity and electron tunneling capability. Meanwhile, the flexible strain sensor showed a significant change in resistance by ∼40% in the 9% strain range, with a gauge factor (GF) value of 4.562 that is twice as high as that of traditional strain gauges. The sensor's response and recovery time of less than 100 ms enhanced its applicability in biomedical arena where continuous monitoring of human health is required. This work offered a new insight towards the development of highly efficient flexible strain sensor for the applications in continuous structural health monitoring and human-machine interface.