Berlin 2008 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 18: SYMPOSIUM Driven Soft Matter III
CPP 18.6: Vortrag
Dienstag, 26. Februar 2008, 18:00–18:15, C 130
Novel estimators for the effective charge of polyelectrolytes during electrophoresis — •Kai Grass1 and Holm Christian1,2 — 1Frankfurt Institut for Advanced Studies, Ruth-Moufang-Strasse 1, D-60438 Frankfurt am Main, Germany — 2Max-Planck-Institut für Polymerforschung, Ackermannweg 10, D-55128 Mainz, Germany
In this contribution, we present two novel estimates for the effective charge (Qeff) of strongly charged polyelectrolyte chains during free solution electrophoresis by means of coarse-grained molecular dynamics simulations.
First, we show that it is possible to calculate Qeff from the electrophoretic mobility obtained from Langevin simulations. Second, we are able to directly obtain Qeff from the number of comoving counter ions. Both estimators yield similar results and show that the effective charge of polyelectrolyte chains grows linear in the number of monomers as previously predicted.
The effective charge is used to evaluate the scaling behavior of the hydrodynamic friction of the polyelectrolyte-counterion-complex. We show the violation of the Nernst-Einstein equation during free solution electrophoresis by obtaining a linear dependence on chain length for the hydrodynamic friction which differs from the scaling of the hydrodynamic size.