| With the rapid progress of technology and manufacturing technology,the rapid popularization of intelligent equipment has greatly contributed to the rapid development of flexible electronics technology.Flexible materials with monitoring functions and can be sensitively converted into usable signals are an important basis for the development of flexible electronics.As a typical flexible functional material,conductive fibers combined with weaving technology has good electrical sensing function,mechanical properties and diverse product forms,which is the ideal material for constructing wearable smart devices,flexible sensors and other high precision flexible electronic products,and achieving health monitoring,disease treatment and sports monitoring applications.Conductive fibers with weave ability have become a rapidly developing and applied research direction in the field of flexible electronics.The growing demand for a wide range of applications is guiding the development of conductive fibers materials.For example,conductive fibers-based flexible sensing materials need to have good mechanical strength,stable air permeability and heat dissipation,as well as good electrical sensing properties to solve the traditional conductive fibers exist in poor wear ability,low sensing sensitivity,structural form is relatively single and other technical problems.Therefore,the preparation of high-sensitivity conductive fibers materials that take into account good mechanical properties,wearing comfort,long-lasting sensing function,and fabric structure diversification has become an important way to promote the transformation and application of conductive fibers-based flexible electronic materials.Electrostatic spinning technology can effectively regulate fibers structure,size,arrangement structure and other parameters to prepare diverse composite fibers including porous structure,etc.It is a common technology for preparing microfibers materials.This thesis is based on electrostatic spinning method with good mechanical strength polyvinylidene(PVDF)fluoride as the base material system of conductive fibers.Through the selective solubility of polyvinylpyrrolidone(PVP),which is easily soluble in water but insoluble in organic reagents,the PVDF-PVP system spinning solution is developed to prepare porous PVDF fibers with the characteristics of porous structure.Based on the high adsorption characteristics of porous PVDF fibers,the porous PVDF conductive fibers are prepared by reducing the silver elemental particle layer on their surface with ascorbic acid as the reducing agent after its full absorption of silver nitrate solution.The combination of woven structure reveals the electrical sensing characteristics of high conductivity,high sensitivity,high linearity and strain sensing range under diverse structural conditions,providing a new and effective method to solve the technical problems of balancing mechanical,functional and structural properties of conductive fibers and to promote the wide application of conductive fibers materials.The main research and conclusions of this thesis are as follows:(1)Using PVP,which is soluble in water but insoluble in organic reagents,as a pore-causing material,PVDF fibers containing PVP prepared by electrostatic spinning machine are immersed in deionized water to dissolve the PVP,and PVDF fibers with porous structure characteristics are obtained.Controllable preparation of porous PVDF fibers porosity can be achieved by regulating the content of PVP in the PVDF-PVP system spinning solution.The good hydrophilicity of porous PVDF fibers establishes the material basis for their efficient adsorption of silver ions during the reduction reaction.The porous PVDF fibers porosity increases and the mechanical strength decreases as the PVP content increases.The porous PVDF fibers with a PVP content of 5 wt.% combines good adsorption properties with high mechanical strength,making it the optimal choice for porous PVDF conductive fibers substrate(porous PVDF fibers).(2)Soak porous PVDF fibers into silver nitrate solution to fully absorb silver ions,then immerse in ascorbic acid solution for silver reduction reaction to generate silver monomer particles on the surface of porous PVDF fibers to obtain conductive PVDF fibers.The silver monolithic particles have uniform particle size and are uniformly and densely distributed in the direction of the surface and thickness of the porous PVDF conductive fibers film,which are firmly bonded with the porous PVDF conductive fiber.The PVP in silver nitrate solution improves the adsorption of silver ions on porous PVDF fibers,effectively increasing the content of silver singlet particles on porous PVDF conductive fibers,and realizing porous PVDF conductive fibers with high electrical conductivity characteristics.The reduced silver conductive process parameter of porous PVDF conductive fibers is 1.2 mol/L concentration of silver nitrate,which can combine good mechanical properties and conductive function.(3)The reduced silver conductive process parameter of porous PVDF conductive fibers is 1.2 mol/L concentration of silver nitrate,which can combine good mechanical properties and conductive function.In addition to good response time,response strain range,response rate and fatigue strength,the porous PVDF conductive fibers can effectively realize strain changes caused by falling small balls,fingers,wrists,elbows and knees,and throat vocalization,verifying its sensing functional characteristics of high sensitivity,high linearity,high cyclic stability and high strain sensing range.The combination of woven structures enables highly sensitive sensing functions under diverse structural conditions. |
