Universal properties of complexes formed by two oppositely charged flexible polyelectrolytes

Results of molecular dynamics simulations for systems with two flexible, oppositely charged polymer chains are presented. It is shown that the chains aggregate into densely packed structures. The universal properties of the formed complexes are investigated as a function of chain length and interaction strength. For weakly interacting systems, a chain length-dependent effective interaction strength is obtained which governs the initiation of the aggregation process. At intermediate interaction strengths, the formed complexes exhibit a scaling behaviour with respect to molecular weight typically for chain molecules in a bad solvent. An unusual weak dependence of the radius of gyration on the interaction strength is found in this regime. Finally, for strong interactions, tightly packed globules are obtained. The radii of gyration and the densities of the complexes are discussed