Synthetic Hagfish Slime Hydrogels With Hyper‐Extensibility, Swellability and Self‐healing in Seawater

ABSTRACT Hagfish slime is an intriguing biological gel‐like material exhibiting rapid gelation, high toughness and ultimate strain to failure, which synergistically serve as an effective deterrence against hagfish's predators. These unique properties arise from the interaction between the slime's building blocks—protein threads and mucin. Here, a systematic approach to develop a hagfish mimetic synthetic hydrogel is developed based on poly(acrylate)‐imidazole chemistry offering self‐healing ability, high swelling ratio of up to 1,200%, and ultimate failure strain of more than 2,000% in natural seawater. Rheological data shows that the storage modulus of the engineered biomimetic slime is two to five of magnitude higher than native hagfish slime and the properties of the hydrogel can be tuned from low swelling with high failure strain to high swelling with lower failure strain by adjusting precursor concentration. The presence of divalent Mg 2+ and Ca 2+ ions is essential to achieve a slime‐like hydrogel with strain‐stiffening, high ultimate failure strain, and rapid self‐healing properties. The hydrogels are prepared using readily available precursors and a simple fabrication protocol that is easily scalable.