基于石墨烯复合薄膜的应变传感器及性能分析

Performance analysis of strain sensor based on graphene composite film

为了克服现有应变传感器在结构健康监测上的不足,以还原氧化石墨烯(rGO)为导电填料,纳米纤维素(CNF)为骨架,硅橡胶(PDMS)为弹性基体,采用溶剂挥发法,制备一种层状结构的柔性应变传感器。分析GO-CNF悬浮液分散性和rGO-CNF/PDMS薄膜传感器的机敏性能,分析传感器的应变-电阻响应机理,建立rGO-CNF/PDMS复合薄膜的压阻行为预测理论模型。研究结果表明:CNF能有效协助rGO的分散,CNF相互交叉、搭接有助于在PDMS基底表面形成多孔隙结构的rGO-CNF薄膜;rGO-CNF/PDMS传感器能承受较大的拉伸变形(应变大于80%),可通过调整基底材料种类和厚度进行调节,并且传感器对应变具有较高的灵敏度(灵敏系数为12~41),可通过调整rGO和CNF的掺量进行调节;rGO-CNF/PDMS复合薄膜的压阻行为预测理论模型所得应变与电阻的关系与实测结果较吻合。

To remedy the deficiency of existing strain sensors in structural health monitoring,using reduced graphene oxide(rGO)as conductive filler,cellulose nanofiber(CNF)as skeleton and polydimethylsiloxane(PDMS)as elastic matrix,a flexible strain sensor with layered structure was prepared by solvent evaporation method.The dispersion of rGO-CNF suspension and electromechanical property of rGO-CNF/PDMS film sensor were analyzed.The mechanical and electrical response mechanism of the sensor was analyzed,and a theoretical prediction model of piezoresistive behavior of rGO-CNF/PDMS composite film was established.The results show that CNF can effectively assist the dispersion of rGO,and its cross-linking and overlapping can help to form porous rGO-CNF film on the surface of PDMS substrate.The rGO-CNF/PDMS sensor can withstand large tensile deformation(strain is larger than 80%)which can be adjusted by the type and thickness of the substrate material.The sensor also has high sensitivity to strain with gauge factors of 12?41 and can be adjusted by the content of rGO and CNF.The relationship between strain and resistance obtained by the theoretical prediction model of piezoresistive behavior of rGO-CNF/PDMS composite film are in agreement with the measured results.