Cylindrical Micelles of Wormlike Polyelectrolytes

We report on a study of the association behavior in solution of semirigid polymers consisting of a poly(p-phenylene) backbone with alternation of negatively charged and hydrophobic moieties. Small-angle X-ray scattering data of aqueous solutions of sulfonated poly(p-phenylene)s show aggregated polymer chains in the form of cylindrical micelles, in which the phenylene backbone is oriented parallel to the long axis of the micelle. The charge density and the length of the alkyl side chains influence the diameter and aggregation number of the micelles. Micelles with strand aggregation numbers between 3 and 11 are formed depending on the hydrophobic−hydrophilic balance. The observed behavior resembles the formation of supermolecular structures by biogenic semirigid polyelectrolytes.