Anomalous polymer diffusion in unentangled systems

Recent theoretical results on anomalous sub-diffusion of polymer coils in unentangled polymer melts and concentrated solutions are discussed. Both 3D bulk systems and polymers confined in 2D monolayers are considered. It is shown that the highly cooperative dynamics in these complex fluids is accounted for by the effect of viscoelastic hydrodynamic interactions, which is strong even in the presence of Langevin friction.