Elastic and shear moduli of single-walled carbon nanotube ropes

Carbon nanotubes are believed to be the ultimate low-density high-modulus f ibers, which makes their characterization at nanometer scale vital for appl ications. By using an atomic force microscope and a special substrate, the elastic and shear moduli of individual single-walled nanotube (SWNT) ropes were measured to be of the order of 1 TPa and 1 GPa, respectively. In contr ast to multiwalled nanotubes, an unexpectedly low intertube shear stiffness dominated the flexural behavior of the SWNT ropes. This suggests that inte rtube cohesion should be improved for applications of SWNT ropes in high-pe rformance composite materials.