Upcycling Waste PET Into Ionic Liquid-Derived Small-Molecule Adhesives

The chemical upcycling of polyethylene terephthalate (PET) presents a critical pathway toward a circular plastics economy, yet existing methods are often hampered by high energy demands and downcycled products. Herein, we report a catalyst- and solvent-free aminolysis strategy that depolymerizes waste PET into a versatile molecular precursor under mild conditions. This precursor is subsequently engineered into a series of low-molecular-weight ionic adhesives via strategic functionalization and supramolecular assembly. By leveraging a rich network of noncovalent interactions, such as hydrogen bonds and electrostatic forces, these materials achieve remarkable cohesion and interfacial adhesion. An alkoxy-functionalized variant demonstrated an adhesion strength of 12.4 MPa on glass, ranking among the strongest small molecular-based supramolecular adhesives reported. This work establishes a sustainable paradigm for converting waste polyester into value-added functional materials, bridging the gap between plastic pollution and high-value manufacturing, promotes the circular economy.