Stimuli-responsive aqueous micelles from an ABC metallo-supramolecular triblock copolymer

A metallo-supramol. ABC triblock copolymer contg. a bis(2,2':6',2''-terpyridine)ruthenium(II) complex as a supramol. connection between the constituting polystyrene-block-poly(2-vinylpyridine) diblock and poly(ethylene oxide) block (PS32-b-P2VP13-[Ru]-PEO70) was prepd. The copolymer was further utilized to prep. aq. micelles consisting of a PS core, a pH-sensitive P2VP shell, and a PEO corona. The micelles were characterized by a combination of dynamic light scattering, TEM, and at. force microscopy. Spherical micelles and a minor fraction of bigger aggregates were obsd. by these three independent techniques. The pH sensitivity of the P2VP shell was demonstrated and the reversibility of the metallo-supramol. complex was studied utilizing a strong competitive ligand. The bis(2,2':6',2''-terpyridine)ruthenium(II) connection was stable, and the integrity of the triblock copolymer was kept in the aq. environment even at extreme pH values. This complex is opened whenever a large excess of a strong competitive ligand was added, allowing the release of PEO coronal chains; the metal complex was then re-formed, even using a different metal ion. This last feature will be used in the near future as a tool to manipulate or to chem. modify nano-objects such as micelles. These micelles attractive for encapsulation and/or release of active specie