Hydrogen-Bonded Supramolecular Network Enabled Gentle Reprogramming of Liquid Crystal Elastomer toward Evolutionary Robot

In nature, many organisms augment chances of survival by reprogramming their structures to evolving environment, among which sea squirts being a prime example. Such reprogramming has been demonstrated in liquid crystal elastomer (LCE) actuator assembled with heat assistance. However, the required temperature being higher than the actuation temperature limits its application. Here, we reported a hydrogen-bonded supramolecular network LCE to construct soft modular and reprogrammable actuator by assembling with a gentle heat treatment. Leveraging the Michael addition reaction, we introduced hydrogen bonding to the LCE matrix with functionalized pyridine monomers. Experimental and molecular dynamics modeling proved the efficient dynamic hydrogen bond exchange at 60 degrees C, significantly lower than the actuating temperature of the LCE. This gave rise to the reversible and robust adhesion of the same collection of LCE modules capable of being built into different bilayers and performing various morphing upon a short thermal stimulation. Therefore, we demonstrated that these comparatively weak cross-links enabled reconfiguration of the LCE actuator. With the developed hydrogen-bonding LCEs, we built proof-of-concept modular reprogrammable robot, performing crawling, sailing, and microcircuit repair tasks. This bioinspired and efficient method for evolutionary LCE robot offers a viable path for further development of intelligent actuators sustainable in complex environments.