Comparison among Multi-Chain Simulations for Entangled Polymers under Fast Shear

Abstract

Due to the slow relaxation nature of polymers, attempts for the development of multi-scale simulations have been made towards the optimization of material processing concerning the molecular characteristics. However, transferability among the utilized models has not been frequently discussed. In this study, a few multi-chain simulations for entangled polymers were compared for the viscosity growth curve under fast shear flows. The multi-chain slip-spring (MCSS) simulations and the multi-chain slip-link simulations (also known as primitive chain network (PCN) simulations) were performed, and the results were compared to the data reported by Cao and Likhtman for the bead-spring model proposed by Kremer and Grest. The conversion parameters for the unit of time and stress were determined from the comparison for the linear viscoelasticity, for which the tree models are essentially transferrable. The obtained viscosity growth curve for the MCSS simulations was in good agreement with that reported for the bead-spring simulations, including the viscosity overshoot. For the PCN simulations, the magnitude of viscosity overshoot was underestimated, whereas the steady state viscosity was reasonably captured. The results demonstrate that the multi-scale strategy by the examined models would work in a certain extent.