Regensburg 2010 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 33: Poster: Charge Effects in Soft and Biological Matter
CPP 33.4: Poster
Mittwoch, 24. März 2010, 17:30–19:00, Poster C
Properties of terminally-charged dendrimers with flexible spacer-chains and explicit counterions: A Monte Carlo study — Jaroslaw Klos1,2 and •Jens-Uwe Sommer1,3 — 1Leibniz Institute of Polymer Research Dresden e. V., 01069 Dresden, Germany — 2Faculty of Physics, A. Mickiewicz University, Umultowska 85, 61-614 Poznan, Poland — 3Institute for Theoretical Physics, Dresden University of Technology, 01069 Dresden, Germany
We study the properties of terminally-charged dendrimers of generations G=5, 6 with flexible spacers of length S=1, 2, 4, 8 accompanied by explicit 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 explicitly with the reduced temperature τ as the main simulation parameter. Our calculations confirm that counterions get localized in the molecules’ interior and, in particular, condense on the terminal gropus as τ is lowered. This, in turn, affects the conformational properties of the molecules that weakly swell at intermediate τ due to dominating repulsion between the terminal groups and shrink in the limit of high and low τ, respectively. Like for neutral dendrimers, we find a substantial decrease of monomer densities with the radial distance from the dendrimers’ center of mass and backfolding of the terminal groups towards the molecules’ interior. Furtheremore, by means of the radius of gyration tensor we conclude that the mean instantaneous shape of dendrimers is spherical for all τ inspected.