Preparation And Characterization Of Composite Micro-nano Fibers By Electrospinning

Electrospinning fibers can be combined with functional nanomaterials to prepare functional composite micro-nano fiber films.Electrospinning fibers uaually use a non-conductive polymer as the matrix framework,but when it is combined with conductive materials,the conductive micro-nano fiber film can be prepared.Electrospinning has a huge potential in the field of creating new conductive fiber materials.This article mainly studies the method of compounding conductive materials with electrospinning polymer fibers,get composite conductive micro-nano fiber membranes,and then explores their conductive properties.The main research results obtained are as follows:(1)Electrospinning was used to assemble silver nanowires(Ag NWs)in micro-nano fibers.The Ag NWs are arranged along the fiber long axis direction by direct dispersion electrospinning and part of the Ag NWs are overlapped with each other to make the fiber membrane have good conductivity.By adjusting the concentration of Ag NWs,the content of Ag NWs in the fiber can be adjusted,thereby controlling the conductivity of the fiber membrane.Based on the premise of precursor liquid’s spinnability,the concentration of Ag NWs can be increased.Eventurally the conductivity of silver nanowire/polyvinylpyrrolidone(Ag NWs/PVP)fiber membrane is increased to 4.74×10-2 S/cm.The self-made parallel metal rod receiving device is used to arrange the Ag NWs/PVP composite fibers in parallel to prepare an anisotropic fiber membrane.(2)In-situ photochemical deposition method was used to grow silver on the surface of TiO2/PVB composite fiber,to prepare "quasi-core-shell structure" composite fiber,in which TiO2/PVB is the core and silver(Ag)is the shell.First,the TiO2/PVB composite fiber was prepared by direct dispersion method.Then the growth of Ag on the fiber surface was achieved by in-situ chemical deposition method under ultraviolet irradiation based on the photocatalytic properties of TiO2.By adjusting the deposition time,the amount of Ag generated can be controlled to further adjust the electrical conductivity of the fiber.The conductivity of the fiber membrane can be up to 5.34×10-2 S/cm.In addition,silver/polyvinyl butyral(Ag/PVB)composite micro-nano fibers were prepared by solution impregnation.The fiber membrane containing silver nitrate(AgNO3)was immersed in the solution where the silver synthesis reaction was taking place,and the silver seeds on the fiber surface were used to induce the large growth of Ag particles on the fiber surface to form Ag/PVB composite fibers.(3)A stepped heat treatment process was used to pre-oxidize and carbonize the silver nitrate/polyacrylonitrile(AgNO3/PAN)fiber membrane,thus to obtain highly conductive silver/carbon(Ag/C)composite micro-nano fibers.The effects of different ratios of AgNO3 to PAN and carbonization temperature on the generation of carbon fibers as well as the distribution of silver particles on the fibers were explored.The pyrolysis process of carbon fibers and the growth process of silver particles were explored.When the mass ratio of AgNO3 and PAN is 1:1,the conductivity of the fiber membrane obtained after carbonization at 800℃ reaches 9.36×102 S/cm.