AFM Investigation of Surface Morphological Changes in Microplastics under Photocatalytic Decomposition

Environmental contamination by persistent micro- and nanoplastics represents a global crisis requiring advanced remediation strategies. Photocatalysis is a promising approach for degrading these polymers, necessitating precise methods to evaluate catalytic efficiency. This work reviews the application of Atomic Force Microscopy (AFM) as a multifaceted tool for characterizing plastic degradation at micro- and nanoscales. AFM provides quantitative data on key morphological and mechanical parameters—such as surface roughness, Young's modulus, average particle size, and adhesion—that serve as direct indicators of polymer breakdown. To standardize the assessment of catalytic performance, we propose a novel quantitative methodology centered on an Integral Degradation Index (IDI). The IDI integrates normalized changes in the aforementioned parameters into a single metric, weighted by their relative significance to the degradation process. This approach enables a comparative and systematic evaluation of different catalytic systems, facilitating the rational design of high-efficiency materials for environmental cleanup. The reviewed studies and the proposed framework establish a foundation for developing a standardized, high-precision protocol to advance photocatalytic solutions for plastic pollution.