A Facile Strategy for Self-Healing Polyurethanes Containing Multiple Metal-Ligand Bonds.

A metal-ligand crosslinked internal self-healing polyurethane is developed using low-cost and commercially available compounds. The mechanical, photoluminescent, and self-healing properties can be governed by incorporating multiple metal-ligand crosslinks with weak and strong coordination bonds and varying the metal ion. In-situ attenuated total reflectance Fourier transform infrared spectroscopy reveals that the metal-ligand bond is cleaved during the damage process while metal ion is still coordinated with the ligand by stronger metal-pyridyl interaction. The multiple metal-ligand coordination facilitates the crosslinks to be fully reformed during the repairing process, leading to the superior self-healing property.