DYNAMICS AND FRICTION IN DOUBLE WALLED CARBON NANOTUBES

Nanotubes have exceptional physical properties theyare as tough as diamond and excellent heat andelectricity conductors. On the other hand theircylindrical shape suggests the possibility of usingthem as mechanical parts at the nanoscale. Recent experiments showed that oscillators or rotationalaxes could be manufactured and controlled. Moreoverthe motion was observed to be wearless and withextremely low friction. This book shows analyticaland numerical results on the dynamics and friction inthose systems. The results show that the empiricallaw stating that friction is proportional to the areaof contact is very well verified. Moreover frictionincreases with temperature. These dependencies can beeasily interpreted. Indeed if the temperature islarge enough so that electronic effects can benegligible then dissipation is only due to thephonons. Consequently if the temperature increasesthe coupling between the phonons and therotational or oscillatory motions increases as wellas friction. In the same manner when the area ofcontact increases the number of available phonons totransport energy increases resulting in a higherfriction force.