Research On Graphene/MXene-PDMS@Sponge Piezoresistive Flexible Pressure Sensor And Its Performance

With the rapid development of flexible electronic devices,flexible sensors are developing in the direction of high sensitivity,high detection limit,high resolution,and arrayed microstructures.For the flexible pressure sensor,the current stage is mainly to change the structure,change the conductive material and the combination of the conductive material and the base material to improve the sensor’s performance indicators such as stability,consistency,and sensitivity.Further exploration is needed to manufacture flexible pressure sensors with simple methods,high sensitivity and high consistency.In this paper,with the purpose of improving the sensitivity,consistency and detection limit of the flexible pressure sensor,a Graphene/MXene（Transition metal carbides and nitrides）-PDMS@sponge-based flexible pressure sensor is prepared,and corresponding performance tests are performed on the prepared sensor.The specific results are as follows:（1）A flexible pressure sensor based on graphene@sponge is prepared.Disperse the graphene in an alcohol solution and immerse it in the sponge several times to form a conductive path.By characterizing the prepared sensor with scanning electron microscope,it can be concluded that graphene can be uniformly distributed inside the sponge and form a conductive path.The graphene@sponge flexible pressure sensor is tested for sensitivity and cyclic loading.The sensor has high sensitivity(0.175 k Pa^-1),and the detection limit is 0 k Pa-5 k Pa.（2）In view of the narrow detection limit range of the graphene@sponge flexible pressure sensor and the unstable appearance during the stability test,in order to stably adhere the graphene inside the sponge,this experiment introduces a low Young’s modulus for PDMS,PDMS is injected into the sponge and then extruded to form a layer of PDMS film inside the sponge,and then the prepared graphene solution is immersed into the sponge so that the graphene adheres to the sponge through PDMS.The graphene-PDSM@sponge flexible pressure sensor was tested for performance.The sensitivity of the sensor reaches 0.075 k Pa^-1,the response time is 120 ms,the detection limit of the sensor is increased to 0 k Pa-45 k Pa,and the sensor shows excellent stability in the cyclic loading-unloading test.And through multiple sets of sensors for testing,the sensors show good consistency.（3）In the sensor preparation process,in order to explore the maintenance of high sensitivity of the sensor while maintaining a wide detection limit,the following experiments were carried out.Fabricated flexible pressure sensor based on graphene/MXene-PDMS@sponge.MXene is added to the experiment.MXene is a new type of two-dimensional carbon material with high conductivity.The relative molecular mass of MXene is larger than that of Graphene,and the volume per unit mass is much smaller,which can solve the problem of incompatibility between the sensitivity of the sensor and the detection line.The performance of the prepared sensor was tested,and the results showed that the sensitivity of the sensor can reach 0.07 k Pa^-1 and the detection limit of the sensor can be increased to 0 kPa-37 kPa.