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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., (© 2022. The Author(s).)

Dielectric elastomer actuators (DEAs) with large actuation strain and high energy density are highly desirable for actuating soft robots. However, DEAs usually require high driving electric fields (>100 MV m−1) to achieve high performances due to the low dielectric constant and high stiffness of dielectric elastomers (DEs). Here, we introduce polar fluorinated groups and nanodomains aggregated by long alkyl side chains into DE design, simultaneously endowing DE with a high dielectric constant and desirable modulus. Our DE exhibits a maximum area strain of 253% at a low driving electric field of 46 MV m−1. Notably, it achieves an ultrahigh specific energy of 225 J kg−1 at only‍‌ ‌‌40‍‌ MV m−1, around 6 times higher than natural muscle and twice higher than the state-of-the-art DE. Using our DE, soft robots reach an ultrafast running speed of 20.6 BL s−1, 60 times higher than that of commercial VHB 4910, representing the fastest DEA-driven soft robots ever reported. Dielectric elastomer actuators require high driving electric fields to achieve high performances for soft robots due to their low dielectric constant and high stiffness. Here, the authors introduce polar fluorinated groups and nanodomains aggregated by long alkyl side chains into the dielectric elastomer design to overcome these issues and develop fast soft robots. [ABSTRACT FROM AUTHOR]

Rapid underwater self‐healing elastomers with high mechanical strength at ambient temperature are highly desirable for dangerous underwater operations. However, current room temperature self‐healing materials have shortcomings, such as low healing strength (below megapascal), long healing time (hours), and decay of healing functions in harsh environments (salty, acidic, and basic solutions), limiting their practical applications. Herein, it is introduced water‐stable Debye forces and high‐density nano‐sized physical crosslinking into one network to achieve a stiff yet rapid self‐healing elastomer that can work in harsh aqueous environments. The obtained elastomer possesses a high Young's modulus of 48 MPa (24 times than that of natural elastomer), and it can achieve 90% of maximum mechanical strength healing for 10 s at ambient temperature in all types of harsh aqueous conditions, outperforming three orders of magnitudes in healing speed of reported room‐temperature self‐healing elastomers with Young's modulus over 10 MPa. The new stiff yet rapidly healable elastomers have great potential in emergent repair in urgent and dangerous cases. [ABSTRACT FROM AUTHOR]