Reversible mechanical bistability of carbon nanotubes under radial compression

Carbon nanotubes (CNTs) have been proposed as one of the most promising materials for nanoelectromechanical systems. Taking advantage of the long range van der Waals interactions between inner walls of CNTs, the tubes have bistable states: the cylindrical CNTs and the flattened CNTs. As an electrical switch, CNT can be switched between ON and OFF states because of their different conductivities. We focus on this mechanical behavior by radial compressing cylindrical CNTs into the flattened CNTs. We show that the radial compressive elastic modulus of CNTs is exponential decay with the tube radius. With the temperature increases, the flattened CNTs can expand to the cylindrical state again. The critical temperature increases with the tube radius. Taking the advantage of the bistability of CNTs, it can be used as nanoswitch, nanosensors and it also can control fluid flow.