Stimuli-Responsive Self-Healing Luminescent Materials Based on Lanthanide Ions and Bipyridine Moieties

Contemporary, luminescent materials possessing rapid stimulus-responsive characteristics demonstrate considerable potential in anti-counterfeiting applications. However, if anti-counterfeiting materials become damaged during use, the integrity of the information will be compromised. Consequently, endowing materials with self-healing ability can ensure the accuracy and integrity of anti-counterfeiting data. In this study, a luminescent metallo-supramolecular polymer is synthesized through the coordination of lanthanide ions (Ln3+) and bipyridine ligands within polyurethane (PU) chains. The PU elastomers created using 4,4′-dicyclohexylmethane diisocyanate display remarkable transmittance and hydrophobic properties following coordination with Ln3+. The dynamic Ln–N coordination imparts self-healing behavior and robust mechanical performance to the PU elastomers. The "antenna effect" imbues the resulting materials with exemplary luminescent properties, and the emission color can be conveniently modulated by adjusting the Eu3+/Tb3+ ratio. Importantly, all luminescent materials exhibit a rapid stimulus-response to acid-base fluctuations through the disruption or restoration of the "antenna effect" between Ln3+ and bipyridine, a critical aspect for the advancement of materials in the anti-counterfeiting and information encryption domains.