SKM 2023 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 20: Polymer and Molecular Dynamics, Friction and Rheology
CPP 20.9: Talk
Tuesday, March 28, 2023, 12:00–12:15, ZEU 255
On the Relaxation Behavior of Linear Chains under Oscillatory Forces — •Ron Dockhorn1 and Jens-Uwe Sommer1,2 — 1Leibniz-Institut für Polymerforschung Dresden e.V., D-01069 Dresden, Germany — 2Technische Universität Dresden, Institut für Theoretische Physik, D-01069 Dresden, Germany
We are studying the relaxation spectra and the force-extension behavior of linear chains under externally driven oscillatory periodic forces f in means of theory and simulations. An oscillatory force f= f0 + fa · sin(ω t) is applied on the chain ends and the response of the end-to-end-distance R as well as the relaxation time τR on the oscillatory frequency ω is investigated. An analytical expression for the end-to-end-distance R(f) is derived by using the Rouse model and compared to simulations. The dissipated energy is calculated by the hysteresis loop A = | ∮df R(f) |, which shows a characteristic maximum at ω τR ≃ 1 for ideal chains independent of the applied force. Contrary, excluded volume chains show a force dependence on the relaxation time τR ∼ f−0.3 as well as a shift on the hysteresis in the Pincus regime. Extensive computer simulations are performed to investigate the scaling properties utilizing the Bond-Fluctuation-Model. Furthermore, the relaxation behavior of different polymer architectures (ring polymer, 31-trefoil knot, two concatenate rings) are compared to the linear chain behavior. The theory and simulations suggests implications for dynamic experiments of biopolymer subject to external forces.