Figure 4.

Plots of storage G’ and loss G” modulus for [PEG-Cat]₄+M^z+ hydrogels with the following program: successive amplitude sweeps of γ = 1–1000% with a 100 s ramp; recovery time of 100 s. This program was repeated a total of four times for each sample including (a) [PEG-Cat]₄+Fe³⁺ and (b) [PEG-Cat]₄+V⁵⁺ hydrogels. Representative samples of (c) [PEG-Cat]₄+Fe³⁺ hydrogels (d) [PEG-Cat]₄+V⁵⁺ hydrogels that undergo self-healing after physical damage.