Octopus Inspired Hydrogel Actuator with Synergistic Structural Color and Shape Change

Abstract Living organisms in nature, such as chameleon and octopus, have amazing performances by changing their color and shape simultaneously for camouflage. Inspired by the camouflage behaviors of octopus, an intelligent hydrogel actuator with tunable structural color is presented in this work. The actuator is fabricated by a typical bilayer of active poly( N ‐isopropylacrylamide) (PNIPAM) hydrogel layer and inert poly(acrylamide‐acrylic acid) hydrogel layer, which endows the actuator shape‐changing by temperature stimulus. The only difference about this actuator is a thin layer of thermoresponsive microgels film embedded into the PNIPAM hydrogel layer, and thus tunable structural color can be displayed with the shape‐changing of the actuator. This makes the preparation procedure straightforward and environment‐friendly. Moreover, when multi‐wall carbon nanotubes are incorporated into the hydrogel, the color and shape of the hydrogel can be controlled via remote near‐infrared irradiation. This smart hydrogel actuator would be of benefit in various fields such as grippers, and soft robots with dynamic camouflage.