The critical micelle concentration for the solution of polyelectrolyte/neutral block-copolymers

The problem of the micelle formation in the solution of diblock copolymers with one polyelectrolyte and one neutral block in selective solvent is considered. It is shown that the application of scaling arguments of Alexander-de Gennes type to this problem leads to the open association picture of the micelle formation. The size distribution function for the micelles in the vicinity of critical micelle concentration (c.m.c.) is rather broad and does not have a pronounced bimodal character. The c. m. c. itself is manifested by the occurrence of the inflection point on the micelles size distribution function. These conclusions are supported by computer simulations. This picture is in contradiction with most of experimental observations which correspond to closed association. Therefore, more experimental and theoretical work is required to achieve an adequate understanding of the structure formation at c.m.c. for block-copolymer solutions.