Optimization of electroactive hydrogel actuators.

To improve actuation of hydrogels, we utilized an emulsion polymerization to engineer porous structures into polyelectrolyte hydrogels. Porous hydrogels generated large deformation as a result of enhanced deswelling mechanisms; for instance, the decreased number of COO(-) groups that must be protonated in porous hydrogels to initiate bending. Measurements of the mechanical properties revealed that porous hydrogels also bend to a larger extent because of their increased flexibility. Overall, our results demonstrate that the fast and large actuation of polyelectrolyte hydrogels can be accomplished by increasing the hydrogel porosity.