Developing an autonomous room temperature self‐healing supramolecular polyurethane (PU) with toughness and stiffness remains a great challenge. Herein, a novel concept that utilizes a T‐shaped chain extender with double amide hydrogen bonds in a side chain to extend PU prepolymers to construct highly stiff and tough supramolecular PU with integrated functions is reported. Mobile side‐chain H‐bonds afford a large flexibility to modulate the stiffness of the PUs ranging from highly stiff and tough elastomer (105.87 MPa Young's modulus, 27 kJ m−2 tearing energy), to solvent‐free hot‐melt adhesive, and coating. The dynamic side‐chain multiple H‐bonds afford an autonomous self‐healability at room temperature (25 °C). Due to the rapid reconstruction of hydrogen bonds, this PU adhesive demonstrates a high adhesion strength, fast curing, reusability, long‐term adhesion, and excellent low‐temperature resistance. Intriguingly, the PU emits intrinsic blue fluorescence presumably owing to the aggregation‐induced emission of tertiary amine domains induced by side‐chain H‐bonds. The PU is explored as a counterfeit ink coated on the predesigned pattern, which is visible‐light invisible and UV‐light visible. This work represents a universal and facile approach to fabricate supertough supramolecular PU with tailorable functions by chain extension of PU prepolymers with multiple H‐bonding chain extenders.
Real-time deployment of adhesives and achieving long-term and highstrength adhesion in various harsh environments remains a significant challenge both in the engineering field and daily life. Herein, the authors report the construction of a super adhesive based on an entirely new mechanism of zwitterion-initiated polymerization. This adhesive can be formed quickly by the rapid spontaneous polymerization of 4-aminostyrene (4-AS) in the presence of acidic polyanion aqueous solution initiated by zwitterions. Direct adhesion and curing process of the adhesive is independent of the environment, and it can be completely cured within 20 min to strongly glue diverse materials spanning from plastics to inorganic substances and metal in various environments (water, acid, alkali, seawater, oil, organic solvent, and low temperature), supposedly due to their marvelous ability to repel the surface liquid barrier layer and form multiple interactions with adherend. Remarkably, this adhesive can maintain high-strength and long-term adhesion to different materials surfaces, quickly repairing broken containers in various conditions. The zwitterion-initiated spontaneous polymerization provides a new strategy for constructing an eco-benign highstrength adhesive with an ability to bond a wide variety of materials with long-term stability against various severe environments.
Self-healing polyurethane elastomers have been extensively studied; however, developing an eco-friendly self-healable waterborne polyurethane (WPU) with exceptional mechanical properties remains a great challenge. Herein, we report healable, and highly tough...
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