Disulfide bonds and metal-ligand co-crosslinked network with improved mechanical and self-healing properties

The simultaneous improvement of mechanical properties and healing efficiency of self-healing polymers is often contradictory because of the different requirements of chain mobility for these two demands. In this study, we have incorporated imidazole-zinc ion coordination bonds into a disulfide based cross-linked network to investigate the influence of non-covalent bonds on the mechanical properties and healing efficiency of dynamic covalent network. It is found that the modulus, strength, and toughness of covalent network were greatly improved by the introduction of non-covalent bonds due to the additional cross-linking and energy dissipation functions of non-covalent bonds. While the time dependent healing test revealed the higher healing efficiency of covalent network by the addition of non-covalent bonds because of their faster exchange dynamics as compared to dynamic covalent bonds. The co-crosslinked network can also be reprocessed by hot press due to the dynamic nature of both covalent and non-covalent crosslinkings.