SKM 2021 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 17: Theory and Simulation (joint session CPP/DY)
DY 17.4: Talk
Friday, October 1, 2021, 14:30–14:45, H3
Ultra-coarse-graining of homopolymers in inhomogeneous systems — •Fabian Berressem1, Christoph Scherer2, Denis Andrienko2, and Arash Nikoubashman1 — 1Johannes Gutenberg University, Mainz — 2Max Planck Institute for Polymer Research, Mainz
We develop coarse-grained (CG) models for simulating homopolymers in inhomogeneous systems, focusing on polymer films and droplets. If the CG polymers interact solely through two-body potentials, then the films and droplets either dissolve or collapse into small aggregates, depending on whether the effective polymer-polymer interactions have been determined from reference simulations in the bulk or at infinite dilution. To address this shortcoming, we include higher order interactions either through an additional three-body potential or a local density-dependent potential (LDP). We parameterize the two- and three-body potentials via force matching, and the LDP through relative entropy minimization. While the CG models with three-body interactions fail at reproducing stable polymer films and droplets, CG simulations with an LDP are able to do so. Minor quantitative differences between the reference and the CG simulations, namely a slight broadening of interfaces accompanied by a smaller surface tension in the CG simulations, can be attributed to the deformation of polymers near the interfaces, which cannot be resolved in the CG representation, where the polymers are mapped to spherical beads.