Polyethylene glycol (PEG) hydrogels were synthesized with two crosslinked networks working in tandem in each sample. The primary network is composed of covalently bound PEG and the secondary network is composed of 4-PEG functionalized with histidine on each arm. The histidine decorated PEG forms metal ion coordinated crosslinks. The loss modulus is dictated by this secondary metal coordinated network and can be controlled through a variety of methods. The heat dissipation amplitude scales with the ratio of histidine to metal ion and the frequency at which the peak is present can be shifted by changing the metal ion. The metal coordinated bonds are shown to be reversible by pH change and can be visualized as a color change within the hydrogel.