Micellar morphologies of charged diblock-copolymers

Using scaling arguments, we consider dilute solutions of diblock-copolymers consisting of a strongly hydrophobic block and a charged block in an aqueo us salt solution. At low salt, the electrostatic repulsion of the charged b lock dominates and we find a transition from spherical to cylindrical micel les as the salt concentration increases. At high salt, the elastic energy o f the hydrophobic core dominates and bilayers are favored. At intermediate salt concentrations cylindrical, spherical. and bilayer morphologies coexis t, suggesting the formation of degenerate, multiply connected structures. T he endcap energy of cylindrical micelles is high, suggesting the formation of long or toroidal cylindrical micelles.