Supramolecular ABA Triblock Copolymers via a Polycondensation Approach:  Synthesis, Characterization, and Micelle Formation

The combinatorial optimization of the reaction conditions of 1,16-bis(2,2‘:6‘,2‘ ‘-terpyridin-4‘-yloxy)hexadecane 1 with RuCl3 under reductive conditions to form supramolecular polymers with a bis-tpy-Ru(II) type connectivity, utilizing gel permeation chromatography as well as UV/vis spectroscopy as screening tools, led to an improved understanding of important polymerization parameters. Moreover, the obtained knowledge could be applied to the designed synthesis of an A-b-B-b-A type supramolecular triblock copolymer utilizing a α-terpyridine-ω-methyl-poly(ethylene glycol) polymer as a chain stopper during the polycondensation-like reaction. The resulting triblock copolymer revealed a composition of approximately 33 repeat units of 1, outlining the value of the applied optimized conditions for its synthesis. Furthermore, it was observed that the synthesized triblock copolymer was able to form micelles in water. Finally, these micelles were investigated by dynamic light scattering, atomic force microscopy, as well as transmission electron microscopy.