Light-Guided Dynamic Liquid Crystalline Elastomer Actuators enabled by Mussel Adhesive Protein Chemistry

Light-guided soft actuators with dynamic polymer networks have drawn much attention in recent years. However, the application of such actuators is limited by their synthetic strategies, polymer structures, and shape-morphing modes. This work reports a new class of liquid crystalline elastomer (LCE) actuators crosslinked by mussel-inspired catechol-Fe (III) complexes. The actuators are mechanically strong while being self-healable, shape-reprogrammable, and reprocessable. Importantly, the formation of catechol-Fe (III) complexes enables the single-component LCE network to exhibit outstanding photothermal effects without any light-absorbing additives. Thus, actuators with designable structures and complex shape-morphing capabilities can be readily programmed with mechanical force coupled with either environmental heating or NIR light irradiation. Furthermore, the material platform provides a robust and flexible way to fabricate actuators with different dimensional structures varying from 1D to 3D. The LCE shows great potential in robotic fields, and as a proof-of-concept, a crawling robot, C-Bot, is specially designed. The robot is capable of moving untethered both on solid-substrate and water surfaces under the guidance of light based on the mechanisms of shape-morphing and Marangoni propulsion, respectively. Surprisingly, different from the vast majority of previously reported LCE-based robots, the C-Bot is strong enough to carry a heavy load while moving.