Multiple morphologies of polyisoprene-block-poly(2-cinnamoylethyl methacrylate) and polystyrene-block-poly(2-cinnamoylethyl methacrylate) micelles in organic solvents

Polyisoprene-block-poly(2-cinnamoylethyl methacrylate) (PI-b-PCEMA) and polystyrene-block-poly(2-cinnamoylethyl methacrylate) (PS-b-PCEMA) formed micelles in solvents, such as cylcopentane (CP), which were selectively poor for PCEMA. Decreasing the length of the soluble blocks relative to that of PCEMA, the shape of the micelles changed from spheres, to cylinders, and to vesicles for both families of diblock copolymers. When a binary solvent mixture was used, the same micellar morphological transitions could be induced for the same diblock by increasing the content of the block selective solvent in the mixture. For PI-b-PCEMA, this meant an increase in the content of hexanes (HX) in THF/HX where HX was good only for PI. Similar trend was observed for PS-b-PCEMA in THF/CP. This represented the first observation of multiple morphologies of diblock copolymer micelles formed in organic solvents. (C) 1997 Elsevier Science Ltd.