MICELLIZATION BEHAVIOR OF (PS)(8)(PI)(8) MIKTOARM (VERGINA) STAR COPOLYMERS

The static and hydrodynamic properties of micelles formed by (PS)(8)(P I)(8) 16-miktoarm (Vergina) star copolymers in the selective, for the PI arms, solvent n-decane were studied. Static and dynamic light scatt ering and viscometry were employed to determine the aggregation number , the size, and shape of the micelles in dilute solutions. All samples formed multimolecular micelles in n-decane. For the low molecular wei ght symmetric sample, experiments indicate that the micelles have a mo re elongated shape. As the compositional asymmetry increased in favor of the soluble branches, the micelles become more spherical. In compar ison to linear diblocks with block lengths equal to the lengths of the respective branches, miktoarm stars order into micelles of lower aggr egation number and larger dimensions. The area, on the core-corona int erface, per junction point was found to be larger in the miktoarm star s. The differences can be attributed to the differences in architectur e and the additional constraints imposed by a common junction point in these highly branched miktoarm stars, which influence the organizatio n of the macromolecules into stable micellar structures in solution.