Conformational behavior of comb-like polyelectrolytes in selective solvent: computer simulation study.

In this work, we present molecular dynamics simulations of comb-like polyelectrolytes in selective solvent. The studied polymers have a neutral backbone and polyelectrolyte side chains. The solvent is poor for the backbone and the theta solvent for the side chains. The polymers are modeled on a coarse-grained level with implicit solvent. The simulations show that the comb-like polyelectrolytes tend to form intramolecular self-organized structures of the pearl necklace type. This type of conformational behavior has been predicted by Borisov and Zhulina (Borisov, O. V.; Zhulina, E. B. Macromolecules 2005, 38, 2506) for neutral comb-like copolymers in selective solvent. The present study shows that comb-like polyelectrolytes in selective solvent exhibit the same type of behavior; however, it can be controlled by one additional parameter, the degree of dissociation of the grafts. The local conformational characteristics are studied using the ensemble-averaged bond angle cosines as functions of monomer position in the chain, which reveal structural details invisible by other means.