A photoresponsive azopyridine-based supramolecular elastomer for self-healing strain sensors

Optical-stimuli materials have been applied in many fields since it can be activated from external system and localized in time and space. Although, optically healable polymers have been well developed in recent years, to be healed under mild conditions remains a big challenge for these materials. Herein, we report the design and synthesis of a metallo-supramolecular polymer containing azopyridine ligands to address this conundrum. The resulting photo-healable polymer is highly stretchable (up to 735%) with a high toughness (16.33 MJ/m(3)) and excellent light-healing efficiency of similar to 90% after three cutting/healing cycles at mild temperature (40 degrees C) in various harsh conditions (e.g. underwater, subzero temperature). Furthermore, a novel bioinspired microcrack nanostructure design is presented to endow the resulted supramolecular elastomer with outstanding sensitivity to strain, which makes it very suitable for human motion monitoring applications. We believe this work will provide afflatus on future design, fabrication and application of photo-stimuli smart materials.