Fabrication And Properties Of Graphene-based Composite Fiber By Polyelectrolyte Complex Spinning Device

Graphene has become one of the high-profile research frontiers and hot spots in the past 15 years,due to its extraordinary properties including Young's modulus,tensile strength,theoretical specific surface area,electrical conductivity,and thermal conductivity.However,how to translate the excellent properties inherent in microscopic building blocks to the macroscopic bulk materials to meet its applications in practice is still a pending challenge.Advance in the recent graphene assembled materials was known as 1D graphene fibers materials.It had been researched widely due to its light weight,high strength,good flexibility and high conductivity etc.,which gave it a good application prospect in the fields of fiber supercapacitors,fiber batteries,intelligent drivers,multifunctional fabrics and so on.In this paper,a new fabrication method of graphene fibers,interfacial polyelectrolyte complexation(IPC)spinning,was proposed.This method was based on the ion complexation between GO spinning solution and chitosan,which was more ideal than the traditional wet process which usually requires volatile organic solvents.The main research contents are as follows:(1)Based on polyelectrolyte complex spinning,a spinning system was designed to fabricate graphene fibers and graphene composite fibers.A theoretical calculation and COMSOL simulation analysis of the flow status of graphene oxide spinning solution in the channel showed that there were shear and tensile force fields in the channel.Tensile flow and shear flow together induced graphene nanosheet assembly,which provides theoretical guidance for the preparation of graphene fibers/composite fibers.(2)Graphene fibers with excellent properties were prepared by IPC spinning and chemical reduction.The effects of spinning parameters,post-treatment process and reduction conditions on the final properties of graphene fibers were systematically investigated,and the IPC spinning process was optimized.The best tensile strength of graphene fibers reached 585.06 MPa.The molecular dynamics simulation showed that fracture and reconstruction of intermolecular hydrogen bonds and ionic bonds between graphene sheets and chitosan molecules consumed energy effectively during tensile stress loading.(3)Graphene/biomass-based composite fibers were prepared by IPC spinning and thermal reduction or chemical reduction.The composite fibers with excellent properties were prepared by using GO/lignin as composite spinning solution.The effect of lignin content and heat treatment process parameters on the physical properties of fibers was investigated.The mechanism of physical properties of graphene fiber enhanced by lignin carbon was investigated.The composite fibers were prepared by using GO/nanocellulose(CNF)as the spinning solution.Electrochemical analysis showed that the presence of CNF increased the hydrophilicity of the composite fibers and effectively avoided the restacking of graphene nanosheets in the reduction process.The ordered and loose arrangement of graphene nanosheets in the fibers made the graphenebased composite fibers electrode had great electrochemical performance.