On the Formation and Characterization of Nanoplastics During Surface Wear Processes

The invasive presence of nanoplastics in various ecosystems makes them a significant environmental problem nowadays. One of the main production mechanisms of nanoplastics is mechanical wear. The combination of friction, abrasion, and shear forces can indeed lead to the progressive fragmentation of polymeric materials. The high surface area–volume ratio of the resulting nanoparticles not only alters the physicochemical properties of the polymers but also leads to increased interaction with biological systems, which raises questions about the persistence of nanoplastics in the environment and their potential toxicity. Despite the growing body of research on microplastics, studies specifically addressing the formation, characterization, and impact of wear-induced nanoplastics remain limited. This article describes current research on the formation mechanisms of nanoplastics generated by mechanical wear, highlighting the tribological processes underlying their release. Advanced characterization techniques used to identify the morphology and composition of these particles are also mentioned. The techniques include atomic force microscopy (AFM), scanning electron microscopy (SEM), and, to some extent, Raman spectroscopy. In the case of AFM, an example of application to the extrusion of nanoplastics from polystyrene surfaces subjected to repeated nanoscratching is also provided.