Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 19: Charged Soft Matter
CPP 19.3: Vortrag
Mittwoch, 28. März 2012, 10:00–10:15, C 243
Simulations of charged dendrimer-linear polyelectrolyte complexes with explicit counterions — •Jarosław Sylwester Kłos1,3 and Jens Uwe Sommer1,2 — 1Leibniz-Institut für Polymerforschung Dresden e.V., 01069 Dresden, Germany — 2Institute for Theoretical Physics, Technische Universität Dresden, 01069 Dresden, Germany — 3Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland
We study complexes comprised of one G4 dendrimer with Nt=32 positively charged end groups and an oppositely charged linear polyelectrolyte accompanied by counterions in an athermal solvent using Monte Carlo simulations based on the bond fluctuation model. In our study both the full Coulomb potential and the excluded volume interactions are taken into account with the reduced temperature τ and chain length Nch as the simulation parameters. Our calculations indicate three temperature ranges that determine the behavior of such complexes. At τcomplex complexes are formed first, which are accompanied by selective counterion localization within the complex at τloc≤ τcomplex. Counterion condensation takes place as temperature is decreased below τcond< τloc. We observe that condensation occurs exclusively on the excess charges in the complex and thus no condensation is observed at the compensation point (Nch=Nt) no matter τ. For Nch ≠ Nt the complex is overally charged. We also find that more rigid chains take a variety of shapes including oblate, spherical and rodlike ones. At low τ a sharp release of tails by long chains is detected by increasing their rigidity.