Abstract
We report on a small-angle neutron scattering (SANS) study of dilute solutions of neutral and charged polystyrene-polyisoprene (PS-b-PI) diblock copolymers in dimethyl acetamide (DMAc), a polar selective solvent for PS. This is a model macromolecular surfactant system: the low glass temperature of the PI block ensures that thermodynamic equilibrium can be attained; the ionic character of the copolymers is provided by a single sulfonate group at the free chain end of the PI block. The crossover from ionic to non-ionic behaviour is investigated by addition of salt. The results are compared to theoretical predictions for micellization of these model macromolecular systems.