Sacrificial bonds break to dissipate energy and can increase the toughness of materials. Incorporating sacrificial bonds into hydrogels through the double network process enabled the first extremely tough hydrogels. In this Focus Review, we discuss the nature of sacrificial bonds, and how they can be used on the macroscale to enable tough soft composite materials. By matching the essence of the double network concept, we can make tough materials from macroscale composites for biomedical and engineering applications.
