No abstract

It is very challenging to achieve polymers that are mechanically robust and fast self-healable at ambient conditions, which are highly desirable for smart materials of the next-generation. Herein, combining dynamic ditelluride bonds and 2-ureido-4­[1H]-pyrimidinone (UPy) moieties in the main chains, a novel type of visible-light-induced self-healing water-dispersed supramolecular polymers (DTe-WSPs) with outstanding healing properties were developed. The prepared DTe-WSPs emulsions showed excellent emulsion stability, and highly transparent DTe-WSPs films obtained from these emulsions exhibited much improved mechanical properties and fast recoverability after the incorporation of UPy groups, owing to the physical cross-links formed by quadruple hydrogen-bonded UPy moieties. Supertoughness (105.2 MJ m–3) and fast self-healability under visible light (healing efficiency of 85.6% within 10 min) could be achieved simultaneously with the adjustment of the ditelluride content and the UPy content, and the toughness of our polymers is higher than those of the reported ambient temperature self-healable polymers. The visible-light-induced ditelluride metathesis is a predominant factor in the healing process of DTe-WSPs, and the ditelluride metathesis triggered by photothermy and hydrogen bonding could also afford the ultimate healing result. Meanwhile, DTe-WSPs can be reprocessed using visible light, providing a facile way to process polymers at mild conditions. To our surprise, the “living” DTe-WSPs exhibited the ability to initiate the polymerization of vinyl monomers under visible light, which is first reported for water-dispersed self-healing polymers. We considered the elaborated design philosophy, based on the readily available, clean, safe, and easily manipulated visible light, which can not only provide inspiration for preparing fast ambient temperature self-healing and reprocessing polymer materials with robust mechanical properties but also develop a new macroinitiator to initiate the ambient temperature polymerization of vinyl monomers.

Visible-light-induced dynamic aromatic Schiff base bond was developed for waterborne polyurethanes, which possess a desirable room-temperature self-healability and excellent mechanical properties (tensile stress: 14.32 MPa; toughness: 64.80 MJ m−3).