Superstretchable, yet stiff, fatigue-resistant ligament-like elastomers
Mengxue Li, Lili Chen, Yiran Li, Xiaobin Dai, Zhekai Jin, Yucheng Zhang, Wenwen Feng, Li‐Tang Yan, Yi Cao, Chao Wang
Abstract
Abstract Ligaments are flexible and stiff tissues around joints to support body movements, showing superior toughness and fatigue-resistance. Such a combination of mechanical properties is rarely seen in synthetic elastomers because stretchability, stiffness, toughness, and fatigue resistance are seemingly incompatible in materials design. Here we resolve this long-standing mismatch through a hierarchical crosslinking design. The obtained elastomer can endure 30,000% stretch and exhibit a Young’s modulus of 18 MPa and toughness of 228 MJ m −3 , outperforming all the reported synthetic elastomers. Furthermore, the fatigue threshold is as high as 2,682 J m −2 , the same order of magnitude as the ligaments (~1,000 J m −2 ). We reveal that the dynamic double-crosslinking network composed of Li + -O interactions and PMMA nanoaggregates allows for a hierarchical energy dissipation, enabling the elastomers as artificial ligaments in soft robotics.