(585a) Insights from Molecular Dynamics Simulation into the Dynamics and Glass Formation Behavior of Polymers Near Interfaces and Under Nanoconfinement

Diverse polymers, small-molecule liquids, and colloids exhibit large alterations in relaxation dynamics, glass transition temperature, and transport properties under nanoscale confinement and in the nanoscale vicinity of interfaces. These alterations have major technological implications, ranging from the stability of polymeric nanostructures to mechanical reinforcement in polymeric nanocomposites to the formation of ultrastable glasses. Moreover, they are implicated in the underlying nature of the glass transition, a long-standing grand challenge of materials science. For this reason, polymer dynamics under nanoconfinement have been the subject of over 30 years of intense study. However, their underlying mechanistic origin and even their overall phenomenology has remained unresolved. Here, I discuss recent progress by our group in employing long-time simulations, in conjunction with theory and experiment, in establishing an understanding of these effects, arriving at a mechanistic picture of their origins, and resolving their ultimate impact on polymer relaxation behavior near interfaces and under nanoconfinement.