Untethered Hydrogel Actuators Generated by an Interfacial Diffusion Reaction toward Pick-and-Place Tasks

Intelligent hydrogel actuators that can display stimuli-responsive shape transformations have attracted tremendous interest and shown promising potential applications in many fields. However, it remains a significant challenge to accomplish remotely controllable actuating performance. Herein, an untethered hydrogel actuator fabricated through an interfacial diffusion reaction toward pick-and-place tasks is presented. The anisotropic structures are obtained by generating Fe3O4 nanoparticles in the local regions of a poly(N-isopropylacrylamide) (PNIPAm) hydrogel, leading to complex shape transformation behaviors. The presence of Fe3O4 nanoparticles endows the hydrogel with magnetically responsive navigation and photothermal conversion capacity. Therefore, untethered soft robots capable of realizing pick-and-place tasks were developed. This presented strategy is expected to promote the development of untethered soft robotics toward pick-and-place tasks.