Dynamic Liquid Crystal Elastomers for Body Heat- and Sunlight- Driven Self-Sustaining Motion via Material-Structure Synergy

Abstract

Self-sustained actuators powered by natural, low-energy sources based on liquid crystal elastomers (LCEs) are attractive as they offer high safety, abundant energy availability, and practicality in applications. However, achieving stable self-sustaining motion with low-energy sources requires high actuation strain rates within a narrow temperature range near ambient conditions – a great challenge as LCEs with low nematic-to-isotropic transition temperatures (T_ni) generally exhibit reduced actuation strain and strain rates. To address this, we synthesized a carbon nanotube-doped LCE with a low T_ni and reversible Diels–Alder crosslinks, termed DALCE, and readily (re)fabricated it into specific structures (e.g., twisted-and-coiled or bimorph shapes). By leveraging material-structure synergy, we achieved both low T_ni and high actuation strain rates, enabling self-rolling, self-breathing and autonomous twisting-untwisting movements powered by ambient/body temperature or natural sunlight. This low-energy, self-sustained actuator design opens new possibilities for LCE-based biomedical applications and naturally powered automatic devices.