, where the diffusion coefficient at short (D " ) and long (D ! ) diffusion times are obtained from PFG NMR. Tortuosity describes the extent to which the pathways within a porous material deviate from a straight line, reflecting the material's structural complexity, and is commonly quantified by comparing the effective distance traveled by diffusing particles to the shortest possible distance between two points (Figure , bottom). Given the large tortuosity values measured in our work, it was essential to extrapolate the short-range diffusion coefficient to values not limited by the finite gradient strengths imposed by the instrumentation, which set a lower bound on the diffusion times suitable for accurate diffusion measurements.