Figure 12. Implementation of the design principle for tough hydrogels– build dissipation into stretchy polymer networks.

Schematics of the implementation strategies with a. interpenetrating or semiinterpenetrating polymer networks, b. polymer networks with high-functionality crosslinks, c. nano-/micro-fibrous polymer networks, and d. polymer networks with reversible crosslinks. e. nominal stress s-stretch λ relations for a PAAm-alginate hydrogel under loading and unloading⁴⁷⁵. f. microscope image of the process zone around the crack in a PAMPS-PAAm hydrogel⁷²². g. microscope image of a fibrous fibrin hydrogel⁷²³. e is adopted from Ref⁴⁷⁵. f is adopted from Ref⁷²². g is adopted from Ref⁷²³.