Brownian dynamics simulation of charged dendrimers : statistical properties

Computer simulation by the method of Brownian dynamics is used to study the statistical properties of neutral and charged dendrimers up to the sixth generation (382 groups) in dilute solutions. Excluded-volume interactions are described by the Lennard–Jones repulsive potential corresponding to an athermal solvent. Electrostatic interactions are considered in the Debye–Hückel approximation. The resultant radial functions of monomer density distribution have a maximum in the core and decline toward the periphery. The average radius of gyration changes with increasing Debye radius r D to a minor extent. The swelling of a neutral dendrimer is adequately described by the Flory mean-field theory. The fractal dimension found for neutral dendrimers is d f = 2.77; for charged dendrimers, it amounts to d f = 2.63 at r D = 0.8 and d f = 2.42 at r D = 100. Terminal groups are distributed all over the dendrimer volume. The maximum in the distribution of terminal groups shifts toward the periphery as r D increases. 1 This work was supported by the Russian Foundation for Basic Research (project nos. 02-03-33135 and 03-03-06379), the INTAS Foundation (grant no. 00-712), and the SUPERNET and SIMU programs of the European Science Foundation. 2 E-mail: [email protected] MODELING