Bionic programmed wearable actuators based on 4D printing of liquid metal-spidroin-liquid crystal elastomer composite

As a pivotal component of robotic systems and wearable devices, flexible actuators play a significant role; while it remains a challenge to achieve intelligent applications due to complex high-degree-of-freedom deformation control and insufficient functionality. Here, inspired by the leaf structure of Ficus benjamina 'Barok', a new type of programmable flexible actuator (PFA) prototype that can be 4D printed is designed, featuring a liquid metal-spidroin-liquid crystal elastomer composite printing functional structure and microstructure substrate, which achieves selective actuation and integrates sensing functions through differentiated manufacturing and pattern design. The interior of PFA is composed of functional masks with photothermal effects and differentiated photopolymerization mesogen structures. The microscopic rearrangement of asymmetric structures at different positions makes remote control of programming deformation convenient. Furthermore, benefiting from the integration of material properties, PFA can sense strain through resistive changes and connect to intelligent devices to transmit signals. The motion support and sensing performance of PFA have the potential to be applied to advanced robotics and human-machine interfaces.