THE DYNAMICS OF MOLECULAR BEARINGS

Various types of molecular bearings have recently been proposed in the growing nanotechnology literature. Using novel molecular dynamics met hods, we have simulated several model graphite bearings. The bearings varied in size from inner shafts of between 4 and 16 Angstrom in diame ter, up to 120 Angstrom in length, and outer cylinders of between 10 a nd 23 Angstrom in diameter, up to 40 Angstrom in length. The turning s haft was either instantaneously started or torqued up to the desired r otational speeds. Frictional properties were size-, temperature- and v elocity-dependent. The presence of more than one bearing vibrational m ode in some simulations created beats that could possibly adversely af fect bearing performance; placing a stretching tension on the bearing suppressed one of the modes and therefore the beats. These and future studies will help evaluate the performance, wear and load-bearing prop erties of fundamental components of nanomachines such as bearings.