Viscolelastic Properties Controlled by pH of Telechelic Metal-Coordinating Hydrogels

Nature uses metal binding amino acids to engineer mechanical properties. An example of this engineering can be found in the mussel byssal thread. This acellular thread contains reversible intermolecular protein-metal bonds, which allows the mussel to robustly anchor to rocks, while withstanding the mechanically demanding intertidal environment. Inspired by this metal-binding material, we present a synthetic hydrogel designed to mimic this bonding behavior. Our study demonstrates that pH is the main driver for the hydrogel's viscoelastic properties, and that a specific metal concentration is not crucial to stable hydrogel formation. This gel has potential applications as an energy dissipating material, and furthers our understanding of the bio-inspired engineering techniques that are used to design viscoelastic soft materials.