Strain sensors based on the resistance change upon exposing to mechanical deformation have been drawn great interests owing to their wide applications including health monitoring, movement detection and structural health monitoring. Recently, conductive polymer composites (CPCs) based strain sensors have attracted attentions due to their quick response in the form of electrical resistance variation when subjected to tensile strain. In this work, two dimensional graphene was used as electrical conductive filler to fabricate thermoplastic polyurethane based strain sensor. Compared with other carbon based electrical conductive fillers, such as one dimensional carbon nanotube and zero dimensional carbon black, graphene possesses superior mechanical flexibility, high restorability and carrier mobility, which enable its application in highly sensitive strain sensors with good reproducibility. The effects of filler loading, strain amplitude and strain rate on the strain sensing behaviors were studied systematically. Wide range of strain sensitivity (gauge factor ranging from 0.78 for TPU with 0.6 wt% graphene at the strain rate of 0.1 min^-1 to 17.7 for TPU with 0.2 wt% graphene at the strain rate of 0.3 min^-1) and good sensing stability for different strain patterns were obtained. The CPCs also demonstrated good recoverability and reproducibility after stabilization by cyclic loading. This study provides a guideline for the fabrication of graphene based polymer strain sensors.

References:

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