Study of the influence of the metal-ligand complex on the size of aqueous metallo-supramolecular micelles

A library of metallo-supramolecular block copolymers has been synthesized, and the micellization behavior of those copolymers in water has been studied. A series of amphiphilic block copolymers composed of poly(styrene) and poly(ethylene oxide) joined by a bis(terpyridine) ruthenium complex were prepared. The micelles formed from these copolymers were characterized by AFM and TEM. The results evidence that the classical scaling laws relating the micelle size to the size of the hydrophobic block are not valid for metallo-supramolecular copolymers. This different behavior is due to electrostatic repulsions between the charged and bulky metal-ligand complexes present at the core-corona interface. If those repulsions are screened by increasing the ionic strength during micelle formation, the classical behavior is observed.