Conformations of flexible dendrimers:: A simulation study

We examine the sizes and conformations of flexible dendrimers of generation numbers G = 4 to G = 9 by means of Monte Carlo simulations on a coarse-grained level. To this end, we introduce a simple, bead-thread model with variable thread-to-bead size ratio 6. In addition, we compare the results from this model to previously calculated ones, based on a soft-sphere-spring model, to test the dependence of the results on the microscopic details. We find a clear insensitivity of the resulting conformational properties on those, both models leading to dense-core density profiles and to increasingly compact structures upon increase of the terminal generation. Moreover, we calculate the distribution of the end monomers, which turns out to be broad and extending throughout the volume occupied by the dendrimer. The dependence of the radius of gyration R-g on the monomer number N does not follow the scaling law R-g similar to N-1/3 that has been often put forward in the literature, but rather it obeys, for high generation numbers, a dependence of the form R-g similar to N-0.24.