Nano-tribology of a polytetrafluoroethylene transfer films using molecular dynamics simulation and microtribometry

Molecular dynamics simulations were performed to examine the effect of chain configuration on the frictional behavior of polytetrafluoroethylene (PTFE) at the molecular level and compared to microtribological studies on aligned transfer films of PTFE. The average friction coefficient was substantially lower (μ < 0.04) for the duration of the experiment. Low friction coefficients (μ < 0.10) were seen for PTFE under slow speed contacts in open air; friction coefficients under MPa of contact pressure and meter per second sliding speed were typically closer to μ = 0.2. The simulation results were obtained from a well-contacted nanoscale region, which made it difficult to make a direct comparison to microscale and macroscale tribological measurements. The dynamics of the transfer films during sliding were responsible for the frictional behavior. Different morphological configurations and the addition of small oligomeric molecules were both expected to show different deformation behavior and frictional coefficients. This is an abstract of a paper presented at the World Tribology Congress III (Washington, DC 9/12-16/2005).