A photoluminescent elastomer with high toughness and fast self-healing behavior enabled by crosslinking polyurethane with reactive lanthanide complex

Abstract

The synthesis of luminescent self-healing materials together with outstanding comprehensive mechanical features is yet a significant challenge due to the contradictory relationship between the self-healing features and mechanical characteristics. In this work, a lanthanide-based photoluminescent elastomer exhibiting super toughness and fast self-healing behavior was prepared via first synthesizing a photoluminescent complex and then utilizing which as the effective functional cross-linkers. The complexes were synthesized with p-aminobenzoic acid and 1,10-Phenanthroline as ligands, Ln³⁺ as the central luminescent ions. The backbone of the polymers was obtained by the polymerization of tolylene-2,4-diisocyanate-terminated polypropylene glycol (PPG-NCO) and isophorone diamine (IPDA). The addition of the complex as a cross-linking agent increases the degree of cross-linking of the polymer chains, and endows the material with good mechanical properties. In addition, self-healing properties was achieved thanks to the dynamic synergistic effect of Ln³⁺-ligand bonding and inter-amide hydrogen bonding. Furthermore, by varying the molar ratio of Eu³⁺/Tb³⁺, multi-color emission which ranging from red to green, has been accomplished. We are confident that the method employed in this study offers a little inspiration on the preparation of toughened luminescent products with self-healing features, which have wide ranging of applications in flexible optical devices, advanced information encryption, and other fields.