The effect of metal ions on the viscoelastic properties of thermosensitive sol-to-gel reversible metallo-supramolecular hydrogels

Smart metallo-supramolecular hydrogels offer attractive possibilities to combine the properties of hydrogels with the self-assembly features offered by metal–ligand coordination. The preparation of metal-bis(terpyridine-poly(N,N-dimethylacrylamide)-b-poly(N-isopropylacrylamide)) ([M(Tpy-PDMA-b-PNIPAM)₂]²⁺) complexes in aqueous media and their use for the elaboration of hydrogels by thermo-induced micellar aggregation is investigated in this study. The rheological behaviour suggested that the metal-bis complexes based on a copolymer having two distinct hydrophilic blocks self-assemble into flower-like micelles. Moreover, the control of the viscoelastic properties of the hydrogels is notably achieved via an appropriate choice of the nature and the molar equivalent composition of metal ions.