Experimental determination of the Young's modulus of individual single-walled carbon nanotubes with single chirality

One-dimensional carbon nanotube (CNT) exhibits excellent mechanical properties and is considered to be an ideal candidate material for the space elevator. However, subtle changes in its chirality strongly affect its physical and chemical properties, including mechanical properties (such as Young's modulus, YM). Theoretical studies reveal that the YMs of perfect single-walled carbon nanotubes (SWCNTs) are in the order of TPa and related to their structures. Nevertheless, due to the lack of SWCNTs samples with well-defined structures and the difficulties in mechanical tests on individual SWCNTs, the theoretical correlations between YM and structure of SWCNTs have not been verified and are still in debate, which directly influences the practical utilization of the excellent mechanical properties of SWCNTs. In this work, we have developed an experimental method to measure the YM of an individual micrometer-scale suspended CNT by atomic force microscopy. A distinct regularity is found between the YM and chirality (i.e., chiral angle and diameter) of SWCNT in the experiment for the first time. By comparing the YMs of SWCNTs with similar diameters and different chiral angles, it manifests that the SWCNT with a near zigzag configuration has a larger YM. This finding suggests that the effect of SWCNT's structures on the YMs cannot be ignored. The developed method of measuring YMs of SWCNTs will be valuable for further experimental research on the inherent physical and chemical properties of SWCNTs.