L. Lue and S.B. Kiselev
to be submitted to the Journal of Macromolecules
We perform Monte Carlo calculations for the mean-square center-to-end distance, mean-square radius of gyration, and second virial coefficient of f=3,4,5 and 6 arm star polymers composed of rigidly bonded hard spheres of varying diameters. As with linear chains, there are two different crossover regimes: (i) crossover from the Gaussian chain to the Kuhnian chain limit, where the penetration function psi(f) increases monotonically with increasing polymer molecular weight, and (ii) crossover from the rigid-rod to the Kuhnian chain limit, where the penetration function decreases with increasing molecular weight. We also extend our previous crossover theory for linear polymers to star polymers. In this theory, the relation between the monomer-monomer interactions of the star polymers and the renormalized parameters of the crossover theory are the same as in the case of linear chains. The predictions of the theory are in good agreement with the simulation data. The crossover theory is able to accurately describe the variation of the infinite molecular weight limit of the penetration function psi*(f) with the number of arms f on the star polymer, and it predicts that psi*(f) approaches 1.55 in the limit as f goes to infinity.