4D printing Light-Driven soft actuators based on Liquid-Vapor phase transition composites with inherent sensing capability

Soft robots capable of responding to different actuation schemes are flourishing due to the appealing advantages of being highly flexible and adaptive to complex environments. However, it remains challenging to produce untether soft actuators that can sense their own motions. Herein, a novel photo-responsive liquid–vapor phase transition composite with integrated actuating and sensing performances is proposed. The composite is operated based on the principle that piezocapacitive sensing and liquid–vapor phase transition are caused by the photothermal effect of the embedded graphene plate. The composite exhibits superior and tunable optically responsive and self-sensing properties. As a proof of concept, the muscle-like actuator with effective actuating and real-time sensing feedback functions is produced. Furthermore, several “Janus” bilayer untethered actuators are fabricated via 3D printing, which can achieve a variety of light-driven programmed locomotion, such as bending, grasping, and crawling. This work holds great promise for designing and fabricating soft robots with integrated self-sensing capacity.