Optical Fiber Waveguiding Soft Photoactuators Exhibiting Giant Reversible Shape Change

Soft actuators, an emerging field in robotics, have great potential for wide‐ranging applications in biology, medicine, engineering, and oceanography. Photoactuators that are stimulated by light to produce reversible mechanical deformation have attracted significant interest in recent years owing to their advantages of high resolution, fast switching, flexible controllability, and electromagnetic interference immunity. Conventional photoactuators rely on free‐space illumination, which limits the control in light‐obstructed surroundings. A low loss optical fiber waveguide‐based soft photoactuator composed of photothermally responsive material hinges and high‐transparency elastomer fiber arms is proposed. When light travels in the elastomer fiber arms, the hinges exhibit a very large shape change so that the arms bend by themselves, with a maximum repeatable bending angle of approximately 145°. The angle is determined by the injected optical power. A fiber photoactuator with dual hinges is designed that is capable of reversible complex deformation. Moreover, in a narrow silicone tube, the fiber photoactuator can still be stimulated with considerable deformation by the light injected along the fiber. A fiber photoactuator‐constructed microhook is demonstrated for grabbing object in water. An optical fiber has been proposed to make consistent illumination for photoactuation fabricated with photothermally responsive materials to realize flexible light‐guide and light‐actuation functions together. The great flexibility with giant deformation and the combination of actuation and control in a soft fiber for the photoactuator can effectively extend the photoactuator applications to the implantable biomedical engineering field.