A redox responsive polymeric gel based on ionic crosslinking.

We report here an electrochemically responsive polymer hydrogel based on ionic crosslinking. The crosslinking by metal cations and anionic carboxylic acid side groups can be controlled by redox reactions. The crosslinks dissociate when the cation crosslinker is reduced to a lower oxidation state and reform following oxidation, which leads to a reversible and localized swelling-contraction. By choosing biocompatible components and miniaturization designs, the system has potential in microrobotic and biomedical applications.