Shear-thinning in Polymer Melts -- Molecular Origins and Hybrid Multiscale Simulations
Abstract
We investigate the molecular origin of shear-thinning in melts of flexible, semiflexible and rigid oligomers with coarse-grained simulations of a sheared melt. Alignment, stretching and tumbling modes or suppression of the latter all contribute to understanding how macroscopic flow properties emerge from the molecular level. By performing simulations of single chains in a shear flow, we identify which of these phenomena are of collective nature and arise through interchain interactions and which are already present in dilute systems. Building upon these microscopic simulations we identify by means of the Irving-Kirkwood formula the corresponding macroscopic stress tensor for a non-Newtonian polymer fluid. Shear-thinning effects in oligomer melts are also demonstrated by macroscopic simulations of a channel flow. The latter have been obtained by the discontinuous Galerkin method approximating macroscopic polymer flows. Our study confirms the influence of microscopic details in the molecular structure of short polymers such as chain flexibility on macroscopic polymer flows.
Keywords
Cite
@article{arxiv.2101.03645,
title = {Shear-thinning in Polymer Melts -- Molecular Origins and Hybrid Multiscale Simulations},
author = {Ranajay Datta and Leonid Yelash and Friederike Schmid and Florian Kummer and Martin Oberlack and Maria Lukáčová-Medvid'ová and Peter Virnau},
journal= {arXiv preprint arXiv:2101.03645},
year = {2021}
}