Mechanical exfoliation assisted with carbon nanospheres to prepare a few-layer graphene for flexible strain sensor

Abstract

Graphene is an ideal material for the preparation of wearable flexible sensors because of its excellent electrical and mechanical properties. However, the preparation of effective graphene is still challenging due to factors such as the low efficiency of the final product, complex processes, environmental pollution, etc. In this study, a method of exfoliating graphite into graphene using water as solvent and carbon nanospheres as exfoliation agents under a high shear rate of microfluidic homogenizer is proposed. The prepared graphene can be used for the preparation of flexible strain sensors by screen printing. The number of layers of the prepared graphene was 2–5 layers. Meanwhile, the sensor had excellent flexibility, which still maintains a stable working state after 100,000 times of flexing test or 1,000 times of abrasion test, and can be used as a wearable flexible strain sensor to monitor the relative change of resistance caused by the movement of the limbs. This method is of great value for the green preparation of graphene and provides a possibility for high-quality and batch production of flexible strain sensors.