A tribological study of double-walled and triple-walled carbon nanotube oscillators
Ma, Chi Chiu
Yam, Chi Yung
Chen, Guan Hua
Date of Issue2005
School of Materials Science and Engineering
We reported in a previous study that energy transfer from the orderly intertube translational oscillation to intratube vibrational modes for an isolated system of two coaxial carbon nanotubes at low temperatures takes place primarily via two distinct types of collective motion of the carbon nanotubes, i.e., off-axial rocking motion of the inner tube and radial wavy motion of the outer tube, and that these types of motion may or may not occur for such a system, depending upon the amount of the initial extrusion of the inner tube out of the outer tube. Our present study, using micro-canonical molecular dynamics (MD), indicates the existence of an energy threshold, largely independent of system sizes and configurations, for a double-walled nano-oscillator to deviate from the intertube translational oscillation and thus to encounter significant intertube friction. The frictional forces associated with several distinct dissipative mechanisms are all found to exhibit no proportional dependence upon the normal force between the two surfaces in relative sliding, contrary to the conventional understanding resulting from tribological studies of macroscopic systems. Furthermore, simulation has been performed at different initial temperatures, revealing a strong temperature dependence of friction in the early phase of oscillation. Finally, our studies of three-walled nano-oscillators show that an initial extrusion of the middle tube can cause inner-tube off-axial instabilities, leading to strong frictional effects.
©2005 Institute of PhysicsThis is the author created version of a work that has been peer reviewed and accepted for publication by Nanotechnology, Institute of Physics. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [DOI: http://dx.doi.org/10.1088/0957-4484/16/8/046].