Polylactic acid/MXene composites: A journey from structural properties to emerging multifunctional applications

During a phase of ever-increasing demands for advanced materials, polymeric composites and nanocomposites have drawn remarkable attention due to their multifunctional applications, ease of processing, and indispensable properties. A significant interest in polymeric composites centers on poly(lactic acid) (PLA) owing to its biodegradability and widespread use in various applications. Nonetheless, most variants developed with PLA suffer from inadequate performance and efficacy during use. Herein, we shed light on the current progress in PLA/MXene composites from the perspective of structural properties. Embarking on the MXene fundamentals and its combinations with PLA, the unique pros of PLA/MXene composites are discussed from the perspective of interfacial engineering, underscoring the significance of thermodynamically stable interactions to achieve strong molecular-level affinity as the foundation for realizing high-performance properties. We carry on this narrative from the realm of processing viewpoints, including solution, melt mixing, electrospinning, and 3D/4D printing of PLA/MXene. The review further addresses the key properties of PLA/MXene composites, including mechanical performance, thermal behavior and stability, electrical and thermal conductivity, photothermal functionality, antibacterial activity, and surface characteristics, together with their degradation mechanisms, environmental impact, and ecotoxicological behavior. We will conclude our review by providing an encyclopedic assessment of PLA/MXene applications, spanning from biomedical, electronics and energy storage, electromagnetic interference shielding, wastewater management, flame retardancy, and shape memory. Critical insights into the current state of PLA/MXene and demanding areas, such as meticulous interfacial engineering, standardized processing protocols, functional longevity, and biodegradability/sustainability, will close out our discussion, offering a useful guideline for future research on PLA/MXene composites.