Quantitative Analysis on the Validity of a Coarse-Grained Model for Nonequilibrium Polymeric Liquids under Flow

Abstract

A detailed quantitative analysis on the validity of a coarse-grained (CG) model for nonequilibrium polymeric liquids under flow was reported. The significant features of CG model included the asymptotic behavior of c̃ xx displayed by the atomistic model attributed to finite chain extensibility due to the strong bond-stretching and bond-bending interactions between atoms behind the chain and the chain rotation occurred in shear flow. The large chain deformations exhibited in the CG model at high values of the Wi number were further reflected for the xy component of the conformation tensor. The CG model predicted correctly only small variations of relaxation time occurred at low strain rates (Wi < 1) and also predicted correctly the incipient flow strength (Wi ≊ 2) beyond which a larger decrease of the relaxation time occurred.