Berlin 2015 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 22: Charged Soft Matter I

CPP 22.7: Talk

Tuesday, March 17, 2015, 11:00–11:15, PC 203

Scaling theory of the counterion-exchange slow mode in salt-free polyelectrolyte solutions — •Won Kyu Kim and Roland R. Netz — Institut für Theoretische Physik, Freie Universität Berlin, Berlin, Germany

We present a scaling theory for the dielectric response due to the counterion-exchange mode in dilute and semi-dilute polyelectrolyte solutions. The mean escape time for the counterion to cross over the energy barrier between two polyelectrolytes is shown to yield a distinct scaling behaviour, depending on the polyelectrolyte length and the polyelectrolyte monomer concentration, and we discuss the result in connection with the slowest dielectric response in the super-low-frequency mode which was recently found. Including the super-low-frequency mode, we present overall scaling relations of relaxation times in various modes induced by the counterions in the solution, which are in agreement with the experimental results, throughout dilute and semi-dilute regimes. Our results suggest that the counterion-exchange mode may resolve the conflicting theoretical interpretations in the polyelectrolyte dielectric spectroscopy particularly in the low-frequency mode.