  For three-dimensional mono-layer molecularly thin-film lubrication, it is
found that elasticity of the substrate affects tribological behaviors of a thin
fluid film confined by two solid substrates.To account for the elastic effects,
a multiscale method that combines an atomistic description of the near region
with a coarse-grained description of the far region of the solid substrate is
developed to simulate the thin-film lubrication. It is shown that in a range of
temperature and film-substrate coupling strength, the multiscale method yields
results in excellently agreement with those obtained from the fully atomistic
simulation. It reveals that the elastic response of substrate can be
effectively rendered in the hybrid scheme. In the application of the multiscale
method to investigate tribological properties of the multi-layer molecularly
thin-film lubrication, it is found that the systematic static friction
coefficient monotonously decreases as the molecular layer thickness in the
fluid film increases. In comparison with the mono-layer molecularly thin-film
lubrication, the multi-layer molecularly thin-film lubrication plays a role in
reducing friction and wear of the system.
