Multiscale Modeling of Nonlinear Rheology for Entangled Polymer Melts

Due to the growing demand for new sustainable polymers with novel molecular structures, there is a pressing need to develop a fast and reliable computational method for predicting their rheological properties, especially under real-world nonequilibrium processing conditions, based on their chemical structure. Recently, we developed a bottom-up multiscale modeling method for in-silico equilibrium rheology of entangled polymer melts. In this method, three simulation models with decreasing resolutions (namely all-atom, coarse-grained, and slip-spring) are performed to probe the polymer relaxation at increasing time and length scales, which are eventually unified to predict the full relaxation spectrum. In this talk, we will show the extension of this method to nonequilibrium rheology. As a proof of concept, we applied this method to atactic polystyrene (aPS) under nonequilibrium shear. Our method predicted the steady shear viscosity of entangled aPS melts across various molecular weights (Mw=60k~300k) and shear rates (Weissenberg number, Wi=0.1~10), demonstrated good agreement with experimental measurements, all achieved without the need for experimental data input. The presented multiscale modeling method paves the way for the rapid and efficient development of sustainable and processable polymeric materials.