The Research Of Preparation And Performance About Wearable Strain Sensor Based On Carbon Nanotubes And Graphene

With the development of flexible electronic devices,flexible wearable sensors have gained extensive attention.Compared with the traditional sensor,it has a very prominent advantage because of the excellent tensile performance which can fit more closely into human body and get more accurate signals.The selection of conductive filler is crucial to make sure the sensor works.In recent years,one-dimensional carbon nanotubes(CNT)and two-dimensional graphene(GR)have attracted extensive attention to researchers.The excellent electrical conductivity and mechanical properties provide important support for the development of flexible sensors.Therefore,this paper mainly selects CNT and GR as conductive fillers to prepare and study the performance of the flexible stretchable sensor.The main contents are shown as follows:(1)Ecoflex/CNT/GR flexible strain sensor was prepared based on CNT、GR and ultrasoft platinum silica gel(Ecoflex).The experimental results show that the sensing range is0-175%,and the highest sensitivity up to 20.The sensor can not only monitor the motion signal of human body,but also be applied in night cycling warning.(2)The substrate of the sensor was prepared by electrospinning and CNT/GR was the suction filtered to prepare PU/CNT/GR flexible strain sensor.The fiber film is obtained by receiving the electrostatic spinning fiber with copper net and tin foil paper respectively.The performance of CNT,GR and CNT/GR sensors prepared by the suction filtering were analyzed by contrast experiments.The experimental results show that the PU/CNT/GR stretchable sensor which prepared by the electrospinning film received by the copper mesh has higher sensitivity(up to 6.5 GF)and stability(more than 1000 cycles).The sensor can monitor physiological signals such as bending and stretching at finger joints,knee movements,pulse at wrist,swallowing and vocalization.(3)Preparing the PU/CNT/GR strain sensor by spraying the conductive fillers CNT and GR alternately on the electrostatic spinning fiber film with a spray pen,and the effect of the electrostatic spinning film received by copper mesh and tin foil paper as the flexible substrate.The performance of the sensors prepared by spraying CNT and GR with a single conductive filler was compared with that prepared by spraying CNT and GR alternately.The results show that the sensitivity of the sensor prepared by alternating spraying CNT and GR on the electrospinning film collected by copper mesh is higher,the highest is 6.3.The performance is more stable and the sensor is able to maintain stable sensing performance after 500 cycles.The sensor can monitor the human body’s tiny movement signal,such as pulse,blink,facial smile.For large movements of the human body,such as finger joint movement,jumping knee joint movement and wrist joint movement can be accurately monitored.It is proved that the sensor prepared by spraying CNT/GR has great potential in human motion monitoring.Conclusion: The flexible stretchable sensor based on CNT/GR prepared by mixing,the suction filtering and spraying which could monitor human movement signals.Thus,it has great potential in human movement and health monitoring.