Dresden 2009 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 42: Polymer Physics IV
CPP 42.3: Talk
Friday, March 27, 2009, 11:00–11:15, ZEU 160
Determination of local mobilities in polymer electrolytes - concepts and simulations — •Diddo Diddens1,2, Andreas Heuer1,2, and Arijit Maitra1,2 — 1Institut für physikalische Chemie, Westfälische Wilhelms-Universität Münster, Corrensstraße 30, 48149 Münster, Germany — 2NRW Graduate School of Chemistry, Corrensstraße 36, 48149 Münster, Germany
In polymer electrolytes based on poly(ethylene oxide) (PEO) one observes a local slowing down of the polymer motion due to attached ions. We study this effect by MD simulations of an electrolyte composed of PEO and LiBF4. It is, however, difficult to quantify locally slowed down polymer dynamics in MD simulations within established polymer theories like the Rouse model, as it describes the motion by nonlocalized modes. Additionally the short timescale dynamics in MD simulations do not obey the Rouse model but are strongly influenced by the local chemical structure. We provide a new statistical method to determine the relative mobilities of slow and fast regions from MD simulation data using the Langevin equation. In addition, Brownian dynamics simulations of various model chains that resemble polymer chains with heterogeneous friction coefficients are analyzed. By comparing molecular dynamics with the ideal Rouse dynamics the timescale for the validity of the Rouse model can be extracted.