Controlled Preparation And Property Study Of Single-wall Carbon Nanotube Fibers And Their Core-shell Structure Fibers

Single-wall carbon nanotube fiber is a macroscopic one-dimensional material composed of well-aligned densely packed single-wall carbon nanotubes.Single-wall carbon nanotube fibers have light weight,high strength,high conductivity,good corrosion resistance and oxidation resistance and therefore,it is expected to get important applications in power transmission,national defense and military industry,aerospace,wearable electronics and so on.Single-wall carbon nanotube fibers prepared by wet spinning have shown high electrical conductivity,and it is easy to realize largescale production due to the good compatibility with the current textile industry.Aiming at the key problem that the properties of carbon nanotube macroscopic fiber are still lower than that of single carbon nanotube,the preparation of highly conductive singlewall carbon nanotube fibers with high density and high alignment by wet spinning was explored.In addition,core-shell structured single-wall carbon nanotube/copper fibers with high specific conductivity were prepared by combined magnetron sputtering and electrodeposition.The main results obtained are as follows:(1)Preparation of single-wall carbon nanotube fibers with high density,high alignment and smooth surface.A wet spinning method based on good solvent exchange strategy was established.The traditional acetone coagulation bath was replaced by N-methylpyrrolidone(NMP)with low diffusion rate in chlorosulfonic acid dispersion to slow down the coagulation process of single-wall carbon nanotube fibers,and then the single-wall carbon nanotube fibers were effectively stretched and refined;The influence of solidification process on the structure and properties of single-wall carbon nanotube fibers was explored,and the optimized wet spinning conditions were obtained.Single-wall carbon nanotube fibers with high density,high alignment and smooth and regular surface were prepared.The conductivity of the fiber is 7.97×106 S m-1,and the tensile strength is 1 GPa,which is 2.6 times higher than that of single-wall carbon nanotube fiber prepared by acetone coagulation bath.(2)Preparation and properties of single-wall carbon nanotube/copper coreshell fibers with strong interfacial bonding.Core-shell structured single-wall carbon nanotube/copper fibers were prepared by combined magnetron sputtering and electrodeposition.It was found that the oxygen-containing functional groups on the surface of single-wall carbon nanotube fibers interact with Cu clusters during the magnetron sputtering process and hence,effectively improve the interfacial bonding of the core-shell fibers.In addition,the copper nanoparticles formed by sputtering can be used as nucleation sites for electrochemical deposition of copper;The influence of electrodeposition process on the structure and properties of single-wall carbon nanotube/copper core-shell fiber was investigated.As a result,core-shell structured single-wall carbon nanotube/copper fibers with a high specific conductivity of 1.01 × 104 S m2 kg-1 and high current carrying capacity of 3.14×105 A cm-2 were obtained.The mechanism of improving the conductivity and current carrying capacity of core-shell fibers by strong interfacial bonding is explained,and the role of single-wall carbon nanotubes in electron transport and current carrying of core-shell fibers is also explained.