  In the present paper we overview our recent results on intrinsic frictional
properties of adsorbed monolayers, composed of mobile hard-core particles
undergoing continuous exchanges with a vapor phase. Within the framework of a
dynamical master equation approach, describing the time evolution of the
system, we determine in the most general form the terminal velocity of some
biased impure molecule - the tracer particle (TP), constrained to move inside
the adsorbed monolayer probing its frictional properties, define the frictional
forces as well as the particles density distribution in the monolayer. Results
for one-dimensional solid substrates, appropriate to adsorbtion on polymer
chains, are compared against the Monte Carlo simulation data, which confirms
our analytical predictions.
