SKM 2023 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 12: Modeling and Simulation of Soft Matter II
CPP 12.3: Talk
Monday, March 27, 2023, 15:45–16:00, MER 02
Dynamics of the Rouse-mode distribution of a Gaussian chain in an external field and connection to spinodal decomposition — •David Steffen1, Jörg Rottler2, and Marcus Müller1 — 1Institut für Theoretische Physik, Georg-August-Universität, 37077 Göttingen, Germany — 2Department of Physics and Astronomy and Stewart Blusson Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
The current description of spinodal decomposition of a homopolymer blend via dynamic self-consistent field theory (D-SCFT) is based on the density of the monomers and uses a time-independent Onsager coefficient. This is sufficient for long wavevectors where the dynamics can be solely described by the diffusion of the center of mass. On small timescales and for larger wavevectors the dynamic is influenced by subdiffusive processes inside the chain. Therefore, a more microscopic description is needed. In this work, we provide an analytical solution for the time-dependent Rouse-mode distribution of a single chain in a weak external field. The time-dependent monomer density can then be obtained via a projection from the Rouse-mode distribution. Although different Rouse-mode distributions yield the same monomer density, an accurate description of the dynamics of the density requires the more microscopic description via the Rouse-modes distribution. This technique can be extended to the spinodal decomposition of a binary homopolymer melt. We compare the analytical results for the density and the Rouse-mode distribution to Monte-Carlo simulations of Gaussian chains.