The Important Roles of Topological Constraints on Interfacial Effects of Nanoconfined Polymers

Interfaces play a significant role in determining the dynamics of nanoconfined polymers. Recent experiments and simulations have revealed the long-range nature over which interfacial effects originating at the polymer-substrate interface can propagate within a thin film. Here, we show that topological constraints, that is, the interpenetration and entanglement between chains directly adsorbed to the substrate and neighboring non-adsorbed chains, play a major role in the suppression of thin film dynamics. This is because such constraints increase motional coupling of free and adsorbed chains, thus giving rise to a mechanism for the propagation of substrate effects. In addition, we demonstrate that the propagation of the suppressed interfacial dynamics can be tuned by controlling the local conformation of chains adsorbed to the substrate surface.