DYNAMICS AND FRICTION IN DOUBLE WALLED CARBON NANOTUBES

Nanotubes have exceptional physical properties, they are as tough as diamond and excellent heat and electricity conductors. On the other hand their cylindrical shape suggests the possibility of using them as mechanical parts at the nanoscale. Recent experiments showed that oscillators or rotational axes could be manufactured and controlled. Moreover the motion was observed to be wearless and with extremely low friction. This book shows analytical and numerical results on the dynamics and friction in those systems. The results show that the empirical law stating that friction is proportional to the area of contact is very well verified. Moreover, friction increases with temperature. These dependencies can be easily interpreted. Indeed, if the temperature is large enough so that electronic effects can be negligible, then dissipation is only due to the phonons. Consequently, if the temperature increases, the coupling between the phonons and the rotational or oscillatory motions increases, as well as friction. In the same manner, when the area of contact increases, the number of available phonons to transport energy increases, resulting in a higher friction force.