Dresden 2006 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 5: Polyelectrolytes
CPP 5.12: Vortrag
Montag, 27. März 2006, 17:30–17:45, ZEU 160
Strong and weak adsorption of polyelectrolyte chains onto the oppositely charged sphere — •Andrey Cherstvy1,2 and Roland Winkler1 — 1Institut für Festkörperforschung, Theorie-II, Forschungszentrum Jülich, D-52425 Jülich, Germany — 2Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzerstrasse 38, 01187 Dresden, Germany
We investigate the complexation of long thin polyelectrolyte (PE) chain with an oppositely charged sphere. In the limit of strong adsorption, when PE chain adapts a definite wrapped conformation on the sphere, we analytically solve the linear Poisson-Boltzmann equation and calculate the electrostatic potential and the energy of the PE complex. We discuss possible attractive interactions between two such non-homogeneously charged complexes and its application to nucleosome core particles. In the limit of weak adsorption, when chain fluctuations are important and PE is crowded around the sphere, we solve the Edwards equation for PE conformations in the Hulthen potential, used as an approximation for the Debye-Hückel potential of the sphere. We predict the shape of the monomer profile away from the sphere and the critical conditions for PE adsorption. We find that the critical sphere charge density depends in a different manner on the Debye screening length than for PE adsorption onto flat surfaces. Our critical adsorption condition is consistent with experiments on complexation of PE with oppositely charged surfactant micelles. We also present results of numerical solutions of the self-consistent field equations for PE adsorption in assemblies of PEs with the oppositely charged spheres.