Metallo-supramolecular hydrogels based on copolymers bearing terpyridine side-chain ligands

A well-defined amphiphilic poly(triethyleneglycol methylether methacrylate)-block-polystyrene (PTEGMA-b-PS) block copolymer with terpyridine groups randomly distributed within the water-soluble block has been sequentially synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. Its self-assembly into micellar structures was analyzed in dilute aqueous solution by dynamic light scattering measurements (DLS). Metallo-supramolecular hydrogels were obtained after the addition of Ni(II) ions to either the precursor PTEGMA homopolymer solution or the PTEGMA-b-PS micellar solution. The PTEGMA-b-PS micelles formed gels at a much lower concentration than the corresponding PTEGMA homopolymer, thus evidencing the influence of the hydrophobic PS block on the critical gelation concentration. The mechanical properties of both hydrogels were finally investigated by rotational rheometry.