We estimate the stiffness of single-walled carbon nanotubes by observing their freestanding room-temperature vibrations in a transmission electron microscope. The nanotube dimensions and vibration amplitude are measured from electron micrographs, and it is assumed that the vibration modes are driven stochastically and are those of a clamped cantilever. Micrographs of 27 nanotubes in the diameter range 1.0–1.5 nm were measured to yield an average Young’s modulus of $〈Y〉=1.25\mathrm{}\hspace{0.5em}\mathrm{TPa}.$ This value is consistent with previous measurements for multiwalled nanotubes, and is higher than the currently accepted value of the in-plane modulus of graphite.

• Received 14 May 1998

DOI:https://doi.org/10.1103/PhysRevB.58.14013