Atomistic simulations of doublewalled carbon nanotubes as rotational bearings

Atomistic simulations of double-walled carbon nanotubes (DWCNTs) as rotational bearings were performed. Molecular mechanics (MM) calculations show that the interlayer energy surface of the bearings is nearly flat. Thermal effects on the bearings were studied with molecular dynamics (MD) simulations at finite temperature. These simulations show that the interlayer corrugation against rotation, and hence the interlayer friction coefficient, is extremely small, suggesting the possible application of DWCNTs as wearless bearings. Extreme operational conditions of the bearings for which the bearings disintegrate are also reported. The reliability of molecular bearings has recently attracted attention.1,2 Previous experimental and modeling work has led to poor results, both in experiment and modeling.3,4 One of the major limitations of such microbearings is that high friction-induced wear results in rapid disintegration. Sug-gestions have been made that wear can be avoided by the use of atomically precise bearings.1 Defect-free DWCNTs possess such atomically precise surfaces, thus holding promise as possible wearless nanoscale bearings. An exampl