Transforming Plastic Waste into Strain Sensors: Multifunctional Upcycled TPEE Elastomers with MXene Multilayer Assemblies

Abstract The persistent rise in global plastic waste, predominantly polyethylene terephthalate (PET), poses significant environmental challenges due to its durability and resistance to degradation. Conventional recycling methods, though effective, limit the value of reprocessed PET products. In contrast, upcycling offers a promising alternative by converting PET waste into high‐value, functional materials. Here, a sustainable approach is reported for upcycling PET waste into thermoplastic polyester elastomer (TPEE)‐based films with advanced properties, specifically designed for applications in strain sensing, conductivity, and photothermal response. Through a layer‐by‐layer deposition technique, TPEE films are fabricated with bio‐compatible chitosan (CH) or poly(diallyldimethylammonium chloride) (PDAC) and MXene nanosheets, forming multilayer structures via hydrogen bonding and electrostatic interactions. These upcycled films exhibit improved mechanical strength, stretchability, and conductivity, demonstrating their potential as sustainable materials for next‐generation wearable and flexible electronics. This approach not only addresses PET waste management but also enhances material functionalities, advancing the field of sustainable polymer upcycling toward multifunctional applications.