Amphiphile micelles formed by polystyrene/poly(2-vinyl pyridine) heteroarmstar copolymers in toluene

We report the micellar behavior of polystyrene/poly(2-vinyl pyridine) heter oarm star copolymers (PS(n)P2VP(n)) in toluene which is a selective solvent of polystyrene. A series of PS(n)P2VP(n) were synthesized by anionic polym erization and their micellar characteristics such as critical micelle conce ntrations (cmc), aggregation numbers, hydrodynamic dimensions and core-coro na sizes were determined by the means of static and dynamic light scatterin g, viscometry and transmission electron microscopy. All these parameters we re studied as a function of the insoluble arm length and the corresponding scaling relations were established. Our system seems to belong to the class of amphiphile micelles characterized by strong dependencies of the aggrega tion number and the microdomain sizes on the insoluble arm length. This beh avior is also characteristic of strongly segregated diblock and triblock co polymer systems. (C) 1999 Elsevier Science Ltd. All rights reserved.