Programmable, Recyclable, and Self-Healing Multifunctional Liquid Crystal Elastomers Enabled by Dynamic Spiral Diacetal Structure

Liquid crystal elastomers (LCEs) have drawn great attention due to their capability of performing large and reversible shape morphing under stimulus. However, challenges remain in developing LCEs that integrate reprogramming, self-healing, and recycling abilities within a single system. Here, we report an LCE by incorporating the spiral diacetal bonds into LCE networks. The spiral diacetal (SDA) bonds enhance the mechanical robustness of the LCE network and undergo a reversible dynamic exchange at elevated temperatures. The dynamic exchange of diacetal bonds allows the network to be rearranged, enabling LCE with reprogramming, self-healing, and recycling capabilities that traditional LCE does not possess. Benefiting from the excellent photothermal effect of YHD1, rapid and precise photothermal-driven actuation was achieved. A bilayer actuator exhibiting a photothermal response gradient was fabricated via thermal welding. Furthermore, soft actuators with a bilayer structure can be programmed into different 3D structures that perform different actuations such as bending, rolling, and grasping under an NIR laser. This work enriches the exchangeable LCEs and provides insights into the design and fabrication of photothermally responsive LCEs with multiple functionalities.