Strong and Tough Liquid Crystal Elastomers Reinforced by Cellulose Nanocrystals for Energy Absorption

ABSTRACT Liquid crystal elastomer (LCE) has emerged as a promising candidate for energy absorption applications, leveraging the unique coupling between the director reorientation of liquid crystal mesogens and the viscoelastic properties of polymer networks. However, achieving synergistic enhancements in mechanical properties (e.g., strength, toughness) alongside energy absorption capabilities remains a significant challenge in current research. This study utilizes oleic acid‐modified cellulose nanocrystals (OCNCs) to reinforce LCE through a dual‐linking mechanism that involves both physical entanglement and nanoscale cross‐linking sites, providing a novel solution to this problem. Mechanical tests indicate that the strength and energy‐absorbing properties of OCNCs‐doped LCE (OCNCs‐LCE) composites are enhanced by more than 10‐fold compared to pure LCE while maintaining tensile elasticity. Notably, the compressive strength of OCNCs‐LCE is significantly higher than that of pure LCE, with its maximum number of compression cycles exceeding 680, demonstrating excellent toughness and fatigue resistance. In addition, impact tests demonstrate that under the same impact energy, the energy absorption performance of OCNCs‐LCE is more than twice that of pure LCE. Vibration tests exhibit that OCNCs‐LCE shows superior internal damping. Falling steel ball impact tests further verify its practical ability to absorb impact energy and protect fragile items from damage.