Micellization behavior of model asymmetric miktoarm star copolymers of the AA'B type, where A is polyisoprene and B is polystyrene

Model asymmetric miktoarm star copolymers of the type AA'B, where A and A' are polyisoprenes (PIs) and B is deuterated polystyrene (PS), were synthesized by anionic polymerization high-vacuum techniques. Their micellization behavior was studied in n-decane, a selective solvent for the PI blocks, and N, N-dimethylacetamide (DMA), selective for the PS blocks. Utilizing static and dynamic light-scattering techniques along with dilute solution viscometry, parameters such as the aggregation number, N-w, the hydrodynamic and viscometric radii were determined. Based on these results, structural parameters of the micelles, that is, core and corona radii, as well as core-corona interfacial area, were calculated. The thermal stability of the micelles was also examined in both selective solvents. The macromolecular architecture was found to have a considerable effect on the micellization behavior of the block copolymers.