Regensburg 2013 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 18: Poster: Polymer Dynamics
CPP 18.1: Poster
Dienstag, 12. März 2013, 18:15–20:15, Poster C
Transport of Polyelectrolytes in Rotational and Pulsed-DC Electric Fields in Confining Cylindrical Geometries — Sorin Nedelcu1 and •Jens-Uwe Sommer1,2 — 1Leibniz Institute of Polymer Research Dresden e.V., Hohe Strasse 6, D-01069 Dresden, Germany — 2Technische Universität Dresden, Institute of Theoretical Physics, Zellescher Weg 17, D-01069 Dresden, Germany
We consider molecular dynamics simulations of the electrophoretic motion of charged polymers in a confining straight cylinder under the influence of an electric field which has a time-independent component orientated along the axis of the cylinder and a component perpendicular to the symmetry axis which rotates with constant angular velocity. The fluid is modeled explicitly, and also the co-ions, counterions and the charged polymer monomers. At moderate applied electric field in the axial direction, and nearly complete separation of the positive from the negative free charges, the electrophoretic velocities of the charged polymer chains in a narrow window of rotational frequencies are found to depend strongly on hydrodynamic friction effects related to changes in the frontal cross-section area and extension due to axial and centrifugal forces. We also investigate electrophoresis in cylinders with a periodic variation (or modulation) of the diameter. In these modulated geometries, the charged polymer chains can be separated only at low fields. At large fields we observe separation effects in modulated geometries if a pulsed electric field is applied. We propose scaling arguments to explain the observed behavior.