Static and kinetic friction of strongly confined polymer films under shear

In the present work, we investigate the dependence of relaxational processes in strongly confined polymer liquids as a function of the molecular mass and of the confining film thickness, both theoretically and experimentally. A qualitative agreement is observed between the theoretical predictions and experimental findings. On the basis of the proposed theory and experimental data, we estimate the relaxation time of the polymer segments in the first surface layer and far away from the surfaces as well as the maximum stress relaxation time.