Thermoresponsive Deformable Actuators Prepared by Local Electrochemical Reduction of Poly(N-isopropylacrylamide)/Graphene Oxide Hydrogels

Inspired by the shape deformations of plants with inhomogeneous structures, more and more attention has been paid to prepare deformable actuators with inhomogeneous structures and precisely program their shape deformations. Here, we report a simple and novel method to prepare graphene oxide/reduced graphene oxide (GO/RGO) nanocomposite hydrogel-based deformable actuators by local electrochemical reduction of homogeneous poly(N-isopropylacrylamide)/GO (PNIPAM/GO) hydrogels. GO nanosheets in PNIPAM/GO hydrogels can be reduced in an electrolytic cell made of two indium–tin oxide (ITO) glass plates, and local reduction can be realized by pasting patterned insulating stickers onto the cathodal ITO glass plate. The reduction of GO nanosheets leads to the breakage of hydrogen bonding between GO nanosheets and PNIPAM chains and hence lower cross-linking densities of the reduced regions. Therefore, the difference in the swelling/deswelling behaviors between the reduced and unreduced sides (or regions) enables the ...