Enhancement of mechanochemical self-blocking and self-healing of early minor damages in polymers through hyperbranched architecture

For more effective removal of the hidden troubles from early minor damages before their spreading out, hyperbranched polyurethane crosslinked by dioxyphenylalanine-Fe3+ (DOPA-Fe3+) and histidine-Zn2+ (His-Zn2+) coordination bonds is synthesized. By taking advantage of the cascading variation of the two types of metal-ligand complexations under the applied force, the growth of minor damages is firstly blocked, and then rehabilitation of the blocked damages takes place without manual intervention. Moreover, the experimental results indicate that the specific structure of hyperbranched macromolecules, which possess plenty of functional groups and great mobility, benefits to construct a stronger network with rapid response than that derived from the linear macromolecules. As a result, the stress-induced micro-voids in the crosslinked hyperbranched polyurethane are much smaller, and its robustness is allowed to be maintained to a higher extent, which is consistent with the concept of timely repairing upon destruction.

Automated summary

By utilizing DOPA-Fe3+ and His-Zn2+ coordination bonds for crosslinking, the spread of minor damages can be prevented and the blocked damages can be repaired without manual intervention. The specific structure of hyperbranched polyurethane enables the construction of a network with rapid response.