Speaking of the strongest fiber material, perhaps you think of Kevlar. That's right, Kevlar, known as the "Armored Guardian", is now widely used in military projects due to the combination of rigidity and flexibility. So if you talk about the most conductive material, perhaps you are thinking of metal material-silver. But if you tell you that there is now such a material that is stronger than Kevlar and has a conductivity close to 80% of copper, what kind of expression would you have? (I add a black question mark emoticon here) Yes, such material has been born. It not only has superior performance, but also has excellent flexibility and light weight. So who is it? It is carbon nanotube fiber (CNTF).
At present, in order to realize the wide application of CNTF, a large-scale production method with controllable and reproducible characteristics is required. Currently, the more popular commercial methods include solution spinning (SS-CNTF), direct spinning (DS-CNTF) and array spinning (AS-CNTF).
Since the solution spinning process separates fiber production from the growth of carbon nanotubes, it allows a clear correlation between the aspect ratio of the original carbon nanotubes and CNTF performance. The basic relationship between the properties of carbon nanotube raw materials and the properties of macro-fibers points out the way forward for the development of CNTF: CNTs with high crystallinity, high aspect ratio and low impurities.
Recently, researchers such as Matteo Pasquali from Rice University in the United States proved that higher quality and longer CNTs can be processed into CNTF through solution, and CNTF has good mechanical and electrical properties and flexibility. The tensile strength of CNTFs prepared by the researchers is 4.2 GPa and Kevlar is 3.6 GPa. The conductivity of CNTFs has increased to 10.9MS/m, which is the first time that CNT fiber has broken through MS/m. According to quality standards, the conductivity of this fiber is about 80% of copper. The research results were published on "Carbon" as a paper entitled "Improved Properties, Increased Production, and the Path to Broad Adoption of Carbon Nanotube Fibers".