Selective Interbundle Cross-Linking for Lightweight and Superstrong Carbon Nanotube Yarns

In this study, a range of carbon nanotube yarn (CNTY) architectures was examined and controlled by chemical modification to gain a deeper understanding of CNTY load-bearing systems and produce lightweight and superstrong CNTYs. The architecture of CNTY, which has polymer layers surrounding a compact bundle without hampering the original state of the CNTs in the bundle, is a favorable design for further chemical cross-linking and for enhancing the load-transfer efficiency, as confirmed by in situ Raman spectroscopy under a stress load. The resulting CNTY exhibited excellent mechanical performance that exceeded the specific strength of the benchmark, high-performance fibers. This exceptional strength of the CNTY makes it a promising candidate for the cable of a space elevator traveling from the Earth to the International Space Station given its strength of 4.35 GPa/(g cm–3), which can withstand the self-weight of a 440 km cable.