An asymmetric A–B–A′ metallo-supramolecular triblock copolymer linked by Ni2+–bis-terpyridine complexes at one junction

Abstract

A metallo-supramolecular triblock copolymer polystyrene-b-polyisoprene–[Ni²⁺]–polystyrene (SI–[Ni²⁺]–S′) has been efficiently prepared using a one-pot, two-step procedure, where the blocks are held by bis-terpyridine complexes at the junction of SI–S′. This specific metallo-supramolecular chemistry is demonstrated to be a robust approach to potentially broaden the diversity of block copolymers. The location of the metal–ligand complexes has a profound influence on the phase separation of the triblock copolymer in the bulk, which results in a distinctive phase segregation between the end blocks and leads to an unexpected asymmetry of the triblock copolymer. The metal–ligand complexes are found to be preferentially located on the adjacent spherical domain and form a core–shell structure. The resulting multiphase material exhibits distinct elastomeric properties with significant toughness and creep recovery behavior. This type of triblock copolymer is anticipated to be a novel class of hybrid thermo-plastic elastomeric material with wide tunability and functionality.