Preparation Of Aligned Silver Nanowire And Its Performance Of Flexible Sensor

With the rapid development of the electronics industry,flexible wearable equipment has begun to gradually enter people’s life.Among them,nano-materials for the conductive substrate of the flexible sensor has become a hot research especially the flexible resistance strain sensor because of its high tensile properties and variable sensitivity is widely used in health monitoring,medical testing and electronic skin.For the strain sensor,where the transparent conductive film layer is the weight of the entire sensor,the sensor signal transmission function depends mainly on the conductive film.In addition to the requirements of the high conductivity and high flexibility,in order to adapt the development of large data in today’s society,flexible sensors should also have high transmittance and high sensitivity.For improving the performance of flexible resistance strain sensor,we usually make a certain exploration and research in the material and structure of the sensor,so as to achieve both mechanical properties and electrical performance of the flexible sensor.In this paper,the preparation of flexible resistance strain sensor with special conductive layer structure is studied including the preparation process of silver nanowires with high aspect ratio,the orientation of silver nanowires on flexible PDMS films and the preparation process and performance testing of flexible strain sensors.In the course of the experiment,we also put forward the analysis and principle hypothesis of directional arrangement of the silver nanowires.Moreover,the real-time wearable monitoring of the flexible sensor was carried out to get a better relevant data.The silver nanowires with high aspect ratio were prepared by one step reduction method.The concept of auxiliary ion additives was introduced by modifying the parameters such as the type of ionic additives,the molar ratio of PVP and so on during the preparation of silver nanowires.The Na Br was used as the second ion additive,and we select PVP from one kind of PVP into two kinds of PVP mixture.The final aspect ratio of preparation of the silver nanowire is more than 800.In the process of directional arrangement of silver nanowires,we used the waterbath pulling method.The selected substrate is the flexible PDMS.In this paper,we mainly discussed the influence of the concentration of silver nanowire solution,the temperature of water bath and pulling speed.Finally,we got the special conductive film of silver nanowire with high conductivity and high transmittance with obvious directional structure and the principle of water bath pulling was analyzed.In the preparation of flexible sensors,we have proposed the use of mask to prepare the base film and the final package cover to form the special PDMS-Ag NWsPDMS sandwich packaging structure to ensure the accuracy and stability of the sensor in the using process.The silver nanowire flexible sensor was tested for performance.The maximum transmittance at 550 nm was 86.3%,while the resistance was only 168 Ω.Importantly,the maximum gauge factor reached as high as 84.6 with 30% strain.,far more than similar sensors.Finally,we conducted a real-time monitoring wearable experiment on the sensor for simulating human activities and got a stable feedback data.In summary,the flexible transparent resistance strain sensor prepared in this paper has the performance which required by the future flexible wearable equipment,and can play a role in the future large data area.