Self-Healing Luminescent Elastomers with Ultrahigh Mechanical Strength, Superior Toughness, and Stimuli-Responsive Luminescence

It remains an inherent challenge to simultaneously endow the self-healing materials with robust mechanical properties and extra functions, such as luminescence. Herein, a series of ultrastrong and tough elastomers were synthesized by simultaneously introducing multiple hydrogen bonds and polydentate chelating lanthanide-terpyridine (Ln3+-Tpy) coordination interactions into polymer chains. The optimal materials (noted as HMPU-Tpy0.1-Ln) show a record-high tensile strength of 40.9 MPa and a superior toughness of 308.63 MJ m–3 with a large extensibility of 2067%. In particular, the true fracture stress (0.91 GPa) of the HMPU-Tpy0.1-Ln polymer is comparable to that of typical spider silk (0.80–1.50 GPa) and its toughness is about 1.9 times that of typical spider silk (≈160 MJ m–3). The dynamic nature of the multiple hydrogen bonds and Ln3+-Tpy coordination also endow the material with acceptable self-healing performance, which can be improved by heating. Superior luminescence performance of the characteristic emission of the corresponding Ln3+ ions can be observed under the excitation of UV light. Besides, the break/recovery of energy transfer between Ln3+ and polymer–ligands triggered by acid–base gas endows HMPU-Tpy0.1-Ln with luminescence off/on switching behavior. We believe that the adopted approach in this work paves the way to prepare ultrastrong self-healing luminescent materials with stimulus-response performance.