Preparation And Research Of High Thermal Conductivity, Flexible And Stretchable Electronic Devices Based On Electrospun Fibers

In recent years,flexible electronic devices have become one of the hotspots in current scientific research.Because the flexible device can maintain stable electrical performance under bending,twisting,folding,stretching,etc.Compared with conventional rigid devices,flexible electronic devices have a wide range of applications in fields such as flexible sensors,wearable devices,energy storage,and implanted medicine.At present,the preparation of flexible electronic devices is mostly obtained by compounding conductive nanomaterials?e.g.nanowires,nanotubes,graphene,etc.?with flexible polymer matrices.Its preparation is similar to composite nanomaterials with high thermal conductivity.However,during the repeated deformation process of the device,the contact resistance between the conductive nanomaterials will increase,and the contact between the nanomaterials and the polymer matrix will be poor.Therefore,the flexible electronic device accumulates a lot of unnecessary heat during operation.If this heat cannot be dissipated from the device in time,it will affect the performance and life of the device and even endanger the safety of the entire system.In addition to excellent mechanical properties and electrical properties,flexible electronic devices also need to have stable thermal properties.It is very important for the development of a new generation of flexible wearable electronic devices to explore appropriate thermal management materials and structures,apply them to the field of flexible electronic devices,and conduct in-depth research on their mechanisms.In this work,according to the orderly arrangement of nanoparticles in the shape controllable electrospun fibers,they can form a stable network structure and in the electrospinning process,high electric field forces can improve the material's thermal conductivity.We used boron nitride nanosheets as inorganic thermally conductive materials,and prepared electrospun fiber-based thermally conductive nanocomposites.Apply it to flexible stretchable electronic devices.First of all,we use electrostatic spinning technology combined with suction filtration and spin coating to prepare a laminated flexible stretchable electrode with both high thermal conductivity and high electrical conductivity.The flexible stretchable electrode has little resistance change and excellent mechanical properties.It can maintain excellent electric performance under 200%strain with an R/R₀ value of 1.46.Moreover,two-dimensional boron nitride nanosheets?BNNSs?enhance the thermal conductivity of the sample.Even under 100%strain,the fluctuation of the equilibrium operational temperature was within 10%.The thermal failure caused by Joule heat during use can be avoided,thereby achieving the purpose of protecting the device and extending the life of the device.The preparation method of the flexible stretchable electrode is simple and the cost is low.It has good application prospects in the fields of new-generation intelligent electronics,high-temperature power supply,electronic equipment and so on.In addition,after optimizing the content of GNRs and BNNSs,a flexible stretchable sensor based on laminated nanocomposites was prepared by using electrospun TPU fiber membrane as a support and using GNRs and BNNSs as active materials for electrical and thermal conductivity.The sensor is highly stretchable and durable,and maintains high thermal stability over more than 1200 cycles.In addition,it has good biocompatibility.Therefore,it can be used to accurately sense the motion of the human body.Based on the high specific surface area and low porosity of the nanofiber membrane,the graphene nanoribbons are more uniformly and densely distributed on the fiber surface.Therefore,it shows high sensitivity,fast response speed,excellent durability and other characteristics.Due to the simple preparation method and excellent performance,it has potential application value in the field of wearable devices.