Enhanced Fatigue\nResistance of Liquid Crystal Elastomers\nEnabled by Dynamic Sacrificial Bonds

Fatigue resistance and elasticity are critical factors\nin extending\nthe service life of liquid crystal elastomers (LCEs) and expanding\ntheir application fields. Currently, most of the LCE-related studies\nfocus on achieving large reversible deformations, while research on\nfatigue-resistant LCE material is relatively limited. Here, we report\na facile strategy to improve the fatigue resistance of LCEs by introducing\npartial dynamic sacrificial bonds (tetraaryl­succinonitrile,\nTASN) into polymeric matrixes. It is found that increasing the amount\nof TASN units leads to a decrease in the LC-to-isotropic phase transition\ntemperature, topology freezing transition temperature, and thermal\nactuation strain while concurrently resulting in an increase in elongation\nat break. Most notably, the LCE–TASN materials exhibit exceptional\nfatigue resistance, as evidenced by their ability to withstand 3000\ncyclic stretching with a substantial 100% strain load, and they also\ndemonstrate rapid self-recovery in as little as 5 min. This remarkable\nperformance is attributed to the reversible dissociation and recombination\nof the dynamic central C–C bonds of the TASN units, a feature\nnot found in conventional LCE materials. The current work provides\ninsight into the design of fatigue-resistant LCEs, thereby helping\nto expand the application of LCEs.