English
Hydrogels are cross-linked polymer networks that swell with water. Due to their soft and water-containing nature, hydrogels are promising materials for applications in many fields such as biomedical engineering, soft robotics, and environmental research. One of the main obstacles to the practical application of hydrogels is their low mechanical strength and toughness. Since the 2000s, many breakthroughs have been made in the development of mechanically strong and tough hydrogels, leading to tremendous advances in soft materials research and our understanding of their failure mechanisms. Long-term mechanical stability, i.e., cyclic fatigue resistance and self-reinforcement properties of hydrogels have also been studied to enable their application as load-bearing materials. This review provides a comprehensive overview of the design principles of tough hydrogels. Strategies to obtain self-growing and reinforcing hydrogels that can adapt to the surrounding mechanical environment are also proposed.
