The results obtained here provide the foundation for possible future work. For instance, the effect of tortuosity on diffusion coefficient values and relevant definitions for tortuosity remain open questions. Unidimensional channels can be particularly examined, where the frequency and magnitude of changes in direction can be analyzed to quantify their occurrence . Another challenge could consist in measuring different diffusion regimes, such as single-file diffusion characterized by a square root time relation in the mean square displacement (MSD) . In this study, materials with MSD relations other than linear were excluded since only materials with high determination coefficients in the linear fit were considered.