弹性导电复合纤维的制备及其应变与温度传感性能

Preparation of elastic conductive composite fiber and its stain and temperature sensing properties

为满足柔性可穿戴传感器的多功能传感需求,实现应变和温度传感具有重大的意义。采用湿法纺丝技术制备聚(3,4-乙烯二氧噻吩)-聚苯乙烯磺酸(PEDOT:PSS)/银纳米线(AgNWs)/聚氨酯(PU)弹性复合导电纤维,研究其拉伸应变传感性能和温度传感性能。结果表明:当AgNWs质量分数为20%,(PEDOT:PSS)与PU质量比为1∶3时,纤维热电性能达到最佳,电导率为47.4 S/cm,塞贝克系数为13.8μV/K,功率因数为902.7 nW/(m·K^(2)),此外,该弹性导电复合纤维具有良好的力学性能,断裂伸长率可达800%,能够检测0%~90%的应变范围,并在100次循环拉伸/回复下依旧保持良好稳定性;同时可将其作为温度传感器,快速检测人体与环境温度。

Objective In order to promote the development of multi-functional flexible wearable sensors,it is of great significance to develop a sensor which could sense both strain and temperature.PEDOT:PSS is a conductive polymer with excellent thermoelectric properties,and can be employed as an ideal base material for stretchable strain sensor and temperature sensor.In this research,a composite conductive fiber was prepared by wet spinning method to achieve strain and temperature sensing.Method The composite conductive fibers with different PU content were prepared by the wet spinning method.The conductivity,Seebeck coefficient,power factor and mechanical property of the composite conductive fiber were measured and analyzed.To verify the ability of this fiber as a strain sensor for motion detection,it was fixed on the index finger and wrist respectively,and the resistance response at different bending angles was measured.Furthermore,the fiber was sewn into a glove,and the temperature-sensing performance was studied.Results With the increase of PU content,the conductive network was destructed by the non-conductive component,resulting in a decrease in conductivity,but the Seebeck coefficient of the composite remained stable because the thermoelectric material was unchanged.The stress and strain of composite fiber were both increased with the increase of PU content.This fiber showed wide work strain range(0%-90%),high sensitivity and good stability.The finger and wrist were bent for 5 times,the maximum resistance changes were basically the same,indicating that the elastic composite wire fiber sensor has good stability.The tensile deformation caused by wrist bending was larger than that caused by finger bending,the corresponding resistance change rate was also much larger than that caused by finger bending.When it is used as a temperature sensor,the voltage is generated by the temperature difference formed at the two ends of the fiber.With the temperature difference increasing,the voltage was increasing too.To detect the water temperature,the fiber was sewn into the glove.Once the hand touches the beaker filled with warm/cold water,a temperature difference was created between the inside and outside of the glove,then a voltage signal was generated.When holding a beaker containing warm water of about 37℃,a positive voltage of about 35μV was generated.After release,the voltage dropped back gradually.When clenched again,the voltage rises at almost the same height.When holding a beaker with ice water at about 0℃,a negative voltage of about 50μV was generated.After release,the voltage returns to 0.When clenched again,a negative voltage of about 45μV was generated.The result demonstrated that this fiber has great promise for temperature sensing.Conclusion The conductive PEDOT:PSS/AgNWs/PU fiber was prepared by wet spinning method.The AgNWs were added to improve the conductivity of the composite fiber.The mechanical properties of PEDOT:PSS could be increased by adjusting the ratio of PU.The PEDOT:PSS/AgNWs/PU composite fiber has good mechanical properties,elongation at break can reach 800%,able to detect 0%-90%strain range,and still maintain good stability under 100 cycles of stretching/recovery.In addition,it can also be used as a temperature sensor to quickly detect human body and environmental temperature,showing great potential in health monitoring.