Bridging Rigidity and Flexibility: Modulation of Supramolecular Hydrogels by Metal Complexation. Issue 12 (17th September 2021)

• Record Type: Journal Article
• Authors: Stach, Oliver S.; Breul, Katharina; Berač, Christian M.; Urschbach, Moritz; Seiffert, Sebastian; Besenius, Pol
• Other Names: Barz Matthias guestEditor.; Nuhn Lutz guestEditor.; Theato Patrick guestEditor.
• Is Part Of: Macromolecular rapid communications. Volume 43:Issue 12(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-09-17
• Subjects: multistimuli‐responsive hydrogelation -- peptide amphiphiles -- supramacromolecular hydrogels -- supramolecular copolymers -- terpyridine coordination; Macromolecules -- Periodicals; Polymers -- Periodicals; Chemistry -- Periodicals; 547.705
• DOI: 10.1002/marc.202100473
• Languages: English
• ISSNs: 1022-1336

Abstract

Abstract: The combination of complementary, noncovalent interactions is a key principle for the design of multistimuli responsive hydrogels. In this work, an amphiphilic peptide, supramacromolecular hydrogelator which combines metal‐ligand coordination induced gelation and thermoresponsive toughening is reported. Following a modular approach, the incorporation of the triphenylalanine sequence FFF into a structural ( C 3 EG ) and a terpyridine‐functionalized ( C 3 Tpy ) C 3 ‐symmetric monomer enables their statistical copolymerization into self‐assembled, 1D nanorods in water, as investigated by circular dichroism (CD) spectroscopy and transmission electron microscopy (TEM). In the presence of a terpyridine functionalized telechelic polyethylene glycol (PEG) cross‐linker, complex formation upon addition of different transition metal ions (Fe 2+, Zn 2+, Ni 2+ ) induces the formation of soft, reversible hydrogels at a solid weight content of 1 wt% as observed by linear shear rheology. The viscoelastic behavior of Fe 2+ and Zn 2+ cross‐linked hydrogels are basically identical, while the most kinetically inert Ni 2+ coordinative bond leads to significantly weaker hydrogels, suggesting that the most dynamic rather than the most thermodynamically stable interaction supports the formation of robust and responsive hydrogel materials. Abstract : Supramolecular peptide nanorods are produced and interconnected through metallo‐supramolecular bis ‐terpyridine complexes in the presence of transition metals (Zn 2+, Fe 2+ and Ni 2+ ) and a telechelic polyethylene glycol cross‐linker at a concentration of 1 wt% in water. The viscoelastic behavior of the reversibly cross‐linked hydrogels is modulated via the transition metal, while thermal toughening is applied using thermoresponsive oligoethylene glycol chains.