Relation between Flows in Complex Geometries and the Dynamics of Entangled Polymer Chains: a Multiscale Simulation Study

Macroscopic flows of entangled polymer melts are determined by the dynamics of a vast number of constituent polymer chains. In other words, macroscopic flows are tightly connected with the microscopic polymer chain dynamics. Therefore, from a simulation perspective, a combined macro-micro description is required to properly analyze polymeric flows. In contrast to conventional approaches that employ constitutive equations, Murashima and Taniguchi developed a MultiScale Simulation (MSS) method for entangled polymer melts (Murashima et al., 2011). In the MSS method, a microscopic model that describes entangled polymer dynamics is combined with a Lagrangian fluid particle method to track the flow history of the strain rate. As a development of our MSS method, flow simulations in a contraction-expansion channel are performed. Using our MSS method, we investigated the relation between the macroscopic flow and the microscopic dynamics of the entangled polymer chains. In particular, we found that the number of entanglements strongly decreases around the middle of the polymer chains. This kind of information can be helpful when designing polymer melts with specific properties.