Bioinspired Stimuli-Responsive Hydrogel with Reversible Switching and Fluorescence Behavior Served as Light-Controlled Soft Actuators

Stimuli-responsive materials with multiple functions occupy a significant position in the research of bionic artificial intelligence materials. It is a challenge to integrate rapid shape deformation and color change synergistically by a simple method in the same system. Herein, an effective strategy to develop an anisotropic bilayer hydrogel actuator with unified complex deformation and color change is proposed via combining the near-infrared (NIR) light-responsive graphene oxide/poly(N-isopropylacrylamide) (GO-PNIPAM) active hydrogel layer and an UV light-responsive fluorescent poly(acrylic acid 4-(1,2,2-triphenylvinyl)] benzyl ester/N-isopropylacrylamide) passive hydrogel layer. The actuator can undergo light-controlled sapphire fluorescence color change and complex shape deformation simultaneously or separately under light irradiation. It can be remotely manipulated without the requirement for additional reagents, and the irradiation dosage can be accurately modulated through adjusting the irradiation parameters. This work provides new perspectives of intelligent systems with synergistic multiple functions, including smart robots, environmental sensors, and intelligent biomimetic devices.