El-Sherbiny, I. M. & Yacoub, M. H. Hydrogel scaffolds for tissue engineering: progress and challenges. Glob. Cardiol. Sci. Pract. 2013, 38 (2013).

Article  Google Scholar 

Nonoyama, T. & Gong, J. P. Tough double network hydrogel and its biomedical applications. Annu. Rev. Chem. Biomol. Eng. 12, 393–410 (2021).

Article  CAS  PubMed  Google Scholar 

Yuk, H., Wu, J. & Zhao, X. Hydrogel interfaces for merging humans and machines. Nat. Rev. Mater. 7, 935–952 (2022).

Article  CAS  Google Scholar 

Long, R. & Hui, C.-Y. Fracture toughness of hydrogels: measurement and interpretation. Soft Matter 12, 8069–8086 (2016).

Article  CAS  PubMed  Google Scholar 

Zhao, X. et al. Soft materials by design: unconventional polymer networks give extreme properties. Chem. Rev. 121, 4309–4372 (2021).

Article  CAS  PubMed  PubMed Central  Google Scholar 

Tang, J., Li, J., Vlassak, J. J. & Suo, Z. Fatigue fracture of hydrogels. Extreme Mech. Lett. 10, 24–31 (2017).

Article  Google Scholar 

Bonn, D., Kellay, H., Prochnow, M., Ben-Djemiaa, K. & Meunier, J. Delayed fracture of an inhomogeneous soft solid. Science 280, 265–267 (1998).

Article  CAS  PubMed  Google Scholar 

Tanaka, Y., Fukao, K. & Miyamoto, Y. Fracture energy of gels. Eur. Phys. J. E 3, 395–401 (2000).

Article  CAS  Google Scholar 

Flory, P. J. & Rehner, J. Jr. Statistical mechanics of cross-linked polymer networks II. swelling. J. Chem. Phys. 11, 521–526 (2004).

Article  Google Scholar 

Hong, W., Zhao, X., Zhou, J. & Suo, Z. A theory of coupled diffusion and large deformation in polymeric gels. J. Mech. Phys. Solids 56, 1779–1793 (2008).

Article  CAS  Google Scholar 

Gong, J. P., Katsuyama, Y., Kurokawa, T. & Osada, Y. Double-network hydrogels with extremely high mechanical strength. Adv. Mater. 15, 1155–1158 (2003).

Article  CAS  Google Scholar 

Sun, J. Y. et al. Highly stretchable and tough hydrogels. Nature 489, 133–136 (2012).

Article  CAS  PubMed  PubMed Central  Google Scholar 

Sun, T. L. et al. Physical hydrogels composed of polyampholytes demonstrate high toughness and viscoelasticity. Nat. Mater. 12, 932–937 (2013).

Article  CAS  PubMed  Google Scholar 

Okumura, Y. & Ito, K. The polyrotaxane gel: a topological gel by figure-of-eight cross-links. Adv. Mater. 13, 485–487 (2001).

Article  CAS  Google Scholar 

Liu, C. et al. Tough hydrogels with rapid self-reinforcement. Science 372, 1078–1081 (2021).

Article  CAS  PubMed  Google Scholar 

Nonoyama, T. et al. Instant thermal switching from soft hydrogel to rigid plastics inspired by thermophile proteins. Adv. Mater. 32, e1905878 (2020).

Article  PubMed  Google Scholar 

Haraguchi, K. & Takehisa, T. Nanocomposite hydrogels: a unique organic–inorganic network structure with extraordinary mechanical, optical, and swelling/de-swelling properties. Adv. Mater. 14, 1120 (2002).

Article  CAS  Google Scholar 

Hua, M. et al. Strong tough hydrogels via the synergy of freeze-casting and salting out. Nature 590, 594–599 (2021).

Article  CAS  PubMed  Google Scholar 

Karino, T., Shibayama, M. & Ito, K. Slide-ring gel: topological gel with freely movable cross-links. Phys. B Condens. Matter 385–386, 692–696 (2006).

Article  Google Scholar 

Bin Imran, A. et al. Extremely stretchable thermosensitive hydrogels by introducing slide-ring polyrotaxane cross-linkers and ionic groups into the polymer network. Nat. Commun. 5, 5124 (2014).

Article  Google Scholar 

Jiang, L. et al. Highly stretchable and instantly recoverable slide-ring gels consisting of enzymatically synthesized polyrotaxane with low host coverage. Chem. Mater. 30, 5013–5019 (2018).

Article  CAS  Google Scholar 

Sakai, T. et al. Design and fabrication of a high-strength hydrogel with ideally homogeneous network structure from tetrahedron-like macromonomers. Macromolecules 41, 5379–5384 (2008).

Article  CAS  Google Scholar 

Kamata, H., Akagi, Y., Kayasuga-Kariya, Y., Chung, U.-I. & Sakai, T. ‘Nonswellable’ hydrogel without mechanical hysteresis. Science 343, 873–875 (2014).

Article  CAS  PubMed  Google Scholar 

Ohira, M. et al. Star-polymer-DNA gels showing highly predictable and tunable mechanical responses. Adv. Mater. 34, e2108818 (2022).

Article  PubMed  Google Scholar 

Shibayama, M., Li, X. & Sakai, T. Precision polymer network science with tetra-PEG gels — a decade history and future. Colloid Polym. Sci. 297, 1–12 (2018).

Article  Google Scholar 

Kim, J., Zhang, G., Shi, M. & Suo, Z. Fracture, fatigue, and friction of polymers in which entanglements greatly outnumber cross-links. Science 374, 212–216 (2021).

Article  CAS  PubMed  Google Scholar 

Nian, G., Kim, J., Bao, X. & Suo, Z. Making highly elastic and tough hydrogels from doughs. Adv. Mater. 34, e2206577 (2022).

Article  PubMed  Google Scholar 

Kamiyama, Y. et al. Highly stretchable and self-healable polymer gels from physical entanglements of ultrahigh–molecular weight polymers. Sci. Adv. 8, eadd0226 (2022).

Article  CAS  PubMed  PubMed Central  Google Scholar 

Nakajima, T. et al. Tough double-network gels and elastomers from the nonprestretched first network. ACS Macro Lett. 8, 1407–1412 (2019).

Article  CAS  PubMed  Google Scholar 

Nakajima, T. et al. A universal molecular stent method to toughen any hydrogels based on double network concept. Adv. Funct. Mater. 22, 4426–4432 (2012).

Article  CAS  Google Scholar 

Zheng, Y. et al. In situ and real-time visualization of mechanochemical damage in double-network hydrogels by prefluorescent probe via oxygen-relayed radical trapping. J. Am. Chem. Soc. 145, 7376–7389 (2023).

Article  CAS  PubMed  Google Scholar 

Gong, J. P. Why are double network hydrogels so tough? Soft Matter 6, 2583–2590 (2010).

Article  CAS  Google Scholar 

Gong, J. P. Materials both tough and soft. Science 344, 161–162 (2014).

Article  CAS  PubMed  Google Scholar 

Dai, X. et al. A mechanically strong, highly stable, thermoplastic, and self‐healable supramolecular polymer hydrogel. Adv. Mater. 27, 3566–3571 (2015).

Article  CAS  PubMed  Google Scholar 

Hu, X., Vatankhah-Varnoosfaderani, M., Zhou, J., Li, Q. & Sheiko, S. S. Weak hydrogen bonding enables hard, strong, tough, and elastic hydrogels. Adv. Mater. 27, 6899–6905 (2015).

Article  CAS  PubMed  Google Scholar 

Wang, Y. J. et al. Ultrastiff and tough supramolecular hydrogels with a dense and robust hydrogen bond network. Chem. Mater. 31, 1430–1440 (2019).

Article  CAS  Google Scholar 

Han, Z. et al. A versatile hydrogel network-repairing strategy achieved by the covalent-like hydrogen bond interaction. Sci. Adv. 8, eabl5066 (2022).

Article  CAS  PubMed  PubMed Central  Google Scholar 

Lin, P., Ma, S., Wang, X. & Zhou, F. Molecularly engineered dual-crosslinked hydrogel with ultrahigh mechanical strength, toughness, and good self-recovery. Adv. Mater. 27, 2054–2059 (2015).

Article  CAS  PubMed  Google Scholar 

Luo, F. et al. Oppositely charged polyelectrolytes form tough, self-healing, and rebuildable hydrogels. Adv. Mater. 27, 2722–2727 (2015).

Article  CAS  PubMed  Google Scholar 

Cui, K. et al. Multiscale energy dissipation mechanism in tough and self-healing hydrogels. Phys. Rev. Lett. 121, 185501 (2018).

Article  PubMed  Google Scholar 

Cui, K. et al. Phase separation behavior in tough and self-healing polyampholyte hydrogels. Macromolecules 53, 5116–5126 (2020).

Article  CAS  Google Scholar 

Li, X. et al. Effect of mesoscale phase contrast on fatigue-delaying behavior of self-healing hydrogels. Sci. Adv. 7, eabe8210 (2021).

Article  CAS  PubMed