Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 42: Polymer Physics IV
CPP 42.7: Vortrag
Freitag, 27. März 2009, 12:00–12:15, ZEU 160
Monte Carlo simulations of dendrimers — •Jaroslaw Klos and Jens-Uwe Sommer — Leibniz Institute of Polymer Research, Dresden, Germany
We inspect star-burst dendrimers by means of Monte Carlo simulations based on the Bond Fluctuation Model. Each molecule is modeled as a collection of monomers connected with bonds so as to form a treelike structure on a cubic lattice. The simulations are athermal since merely the excluded volume interactions between the monomers and bond constraints are considered. Through a variation of dendrimers’ generation number G and spacer length S we focus on their mean instantaneous shape, size and radial distributions of monomers and terminal groups. The calculations show that the shape of dendrimers changes monotonously from oblate to spherical as the increase in their molecular weight N is caused by an increase in G, while for fixed G it is hardly affected by variations of S. The obtained data lead to the conclusion that the radius of gyration obeys satisfactorily the scaling prediction Rg∼ (SG)2/5N1/5 with G and S treated as two independent variables. Moreover, our simulations support the dense-core picture of dendrimers due to a substantial decrease of monomer densities with the radial distance from the dendrimers’ centre of mass. The decrease is strictly monotonous for low generation molecules, whereas for ones with higher G there is either a local maximium or relatively broad plateau in the density profiles that correspond to the dendrimers’ domain. The interior of dendrimers is also penetrated by the terminal groups due to finite values of the end-group densities in that area.