| 초록 |
Most toroidal micelles reported are ring-closure products of rod-shaped micelles, which coexist with the precursor micelles. However, highly uniform donut-shaped micelles were first observed from PI-b-P2VP (Polyisoprene-block-poly(2-vinylpyridine) block copolymer. (Angew. Chem. 2009, 121, 4664) It might have been possible only if the micelles change the structure from a relatively uniform morphology like spherical micelles. In this study, formation pathway of the toroid micelles was investigated by monitoring the micelle structures at different solvent compositions. At the initial stage near the critical micellar composition, embryo-micelles of imperfect spherical shape were observed. At the intermediate condition between the embryo-micelles and the stable uniform micelles, their shape and size are not highly uniform. It is likely that smaller, immature micelles attract dissolved block copolymers more strongly than matured, bigger micelles and their size become similar during growth. |
