ABSTRACT
An ideal MWNT has no chemical bond between the atomistically
smooth carbon layers within the cylindrically nested structure;
the only inter-layer coupling comes from the weak van der
Waals (vdW) interaction among constituent atoms. The loose
coupling between concentric carbon cylinders alludes to a striking
telescoping property whereby individual cylinders can slide and
rotate with respect to each other [351]; see Fig. 11.1 for the internal
sliding behavior of a double-wall carbon nanotube. The earlier
experiments confirmed that both the translational [28, 351, 352]
and rotational shear strengths [353] within an isolated MWNT
can be less than 1 MPa, extremely small compared with other
solids. This extremely low friction against the interwall motion
within of MWNTs led to the idea of constructing a new set of
mechanical (and electromechanical) nanodevices that are endowed
with the high-speed, low-friction, and low-power-consumption
Figure 11.1 (a) Pullout of a double-wall carbon nanotube. The yellow balls represent for atoms of the inner wall while the purple ones denote those
of outer wall. (b) Diagram of the vdW force FvdW, the pullout force FI, and stress components τ on sliding interface. Reprinted from Carbon, 48(10), Li, Y., Hu, N., Yamamoto, G., Wang, Z., Hashida, T., Asanuma, H., Dong, C., Okabe,
T., Arai, M., and Fukunaga, H., Molecular mechanics simulation of the sliding
behavior between nested walls in a multi-walled carbon nanotube, 2934-
2940, Copyright (2010), with permission from Elsevier.
