  Using the phenol-terminated polycarbonate blend as an example, we demonstrate
that the hydrodynamic boundary conditions for a flow of an adsorbing polymer
melt are extremely sensitive to the structure of the epitaxial layer. Under
shear, the adsorbed parts (chain ends) of the polymer melt move along the
equipotential lines of the surface potential whereas the adsorbed additives
serve as the surface defects. In response to the increase of the number of the
adsorbed additives the surface layer becomes thinner and solidifies. This
results in a gradual transition from the slip to the no-slip boundary condition
for the melt flow, with a non-monotonic dependence of the slip length on the
surface concentration of the adsorbed ends.
