fig2

Figure 2. Molecular/chain-level structure strategy. (A) Chain flexibility tuned by molecular weight and degree of polymerization^[40,52]. Copyright 2021, The American Association for the Advancement of Science; Copyright 2022, Wiley-VCH; (B) Crosslinking density^[53]. Copyright 2023, Wiley-VCH; (C) Branching and side-chain structures^[41]. Copyright 2021, American Chemical Society; (D) Self-assembly and noncovalent interactions; (E) Double/multiple network structures. (D and E) are reprinted with permission from Ref.^[34]. Copyright 2024, Springer Nature; (F) Slide-ring and fully sliding structures^[54]. Copyright 2010, Elsevier; (G) Sacrificial network design^[55]. Copyright 2025, Innovation Press. PVA: Poly(vinyl alcohol).