(693e) Bottom-up Multiscale Simulation: Predicting Entangled Polymer Rheology in and out of Equilibrium

The increasing demand for sustainable polymers with novel molecular structures has prompted the urgent need for a computational approach to reliably predict their rheological properties, particularly under real-world processing conditions. We introduce a multiscale modeling method for rheology simulation of entangled polymer melts both in and out of equilibrium. This method employs three simulation models, ranging from all-atom to coarse-grained to slip-spring, to investigate polymer relaxation at increasing time and length scales. Start with the atomistic structure and force fields, the coarse-grained and slip-spring models are parameterized in a bottom-up manner. This enables the in-silico prediction of rheological properties of highly entangled polymer melts without any experimental inputs. Using polystyrene and polyacrylates melts as examples, we have demonstrated that this method can accurately capture the effect of tacticity, molecular weight, and polydispersity on the equilibrium viscosity and rheological master curve as observed in experiments. We further extend this method to nonlinear shear rheology and have showcased its efficacy through favorable agreement in shear-rate dependent viscosity compared to experimental data.