Photothermal Surface Plasmon Resonance and Interband Transition‐Enhanced Nanocomposite Hydrogel Actuators with Hand‐Like Dynamic Manipulation

Abstract Hydrogel actuators represent a powerful tool due to their ability to capture, move, and be manipulated, which has applications in diverse fields. The development of hydrogel actuators capable of localized movement, where only a part of the whole system moves, wireless remote control, and flexible shape‐changing is critical and challenging to fulfill their potential. Here, photothermal hydrogel actuators are designed and fabricated to accomplish a precise hand‐like manipulation of encapsulating and finger‐like one‐by‐one bending by light. A thermoresponsive poly( N ‐isopropylacrylamide) (PNIPAm) active layer and a non‐thermoresponsive poly(acrylamide) passive layer are combined to generate a thermal‐expansion coefficient mismatch among the interface and this energy eventually transforms into a bending motion. As an energy transformation agent, the gold nanoparticles doped in the PNIPAm hydrogel absorb the light energy and transform it into thermalenergy effectively as a result of a surface plasmon resonance electron–phonon process and intrinsic interband transitions. The resulting nanocomposite actuators exhibit flexible, reversible motions and local hand‐like finger flexion driven by either flood illumination or local irradiation. The developed programmable actuators are expected to be an attractive candidate for the next generation of “smart” soft robots.