(699e) [Invited Talk] Interfacial Dynamics in Layered Polymeric Systems

Knowledge of interfacial dynamics in layered polymeric systems is not only important from the fundamental physics point of view but is also of interest to a wide variety of applications in electronics and chemical industries. In separation processes, the flux through polymeric membranes can be increased by reducing their thickness, however, such thin membranes need to be supported on a stiff material for mechanical stability. The separation properties of such supported membranes are affected by the nature of the interface formed with the support. We have used molecular simulations to study the role of the interface in governing chain and penetrant molecule dynamics in layered polymer systems.

In the first part, results will be presented for a system consisting of alternating layers of different polymers that are modeled at the coarse grained level. The effect of interlayer interactions and the differences in the chain flexibility between the layers on the detailed chain dynamics will be discussed. The second part of the presentation will focus on a layered system consisting of alternating layers of polyacrylate and polysulfone. This system was studied using atomistically detailed models that enable accounting for the effects of the specific chemical interactions and the chain topology on the system behavior. In both the model systems, the volumetric and dynamic properties of the individual polymer layers were found to be altered only near the interface, while the properties of the bulk regions of the layers were very similar to those of their unsupported counterparts. The property changes observed in the interfacial regions were governed by the stiffness of the other layer (e.g., soft or hard confinement) and the nature of the interlayer interactions. The effect of the interface on the dynamics of penetrant molecules will also be discussed.