ELECTROSTATICS IN THE SELF-ASSEMBLY OF MACROMOLECULAR SURFACTANTS

We report on a small-angle neutron scattering (SANS: study of dilute s olutions of neutral and charged polystyrene-polyisoprene (PS-b-PI) dib lock copolymers in dimethyl acetamide (DMAc), a polar selective solven t for PS. This is a model macromolecular surfactant system: the low gl ass 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 c rossover From ionic to non-ionic behaviour is investigated by addition of salt. The results are compared to theoretical predictions for mice llization of these model macromolecular systems.