Figure 4.

Normalized diffusivities predicted by the MSDM model compared against experimentally obtained values. Experimental data (gray circles; error bars denote mean ± s.d.; n = 10) and theoretical predictions (lines) for the normalized diffusivity, D/D₀, versus solute hydrodynamic radius (r_s) for PEG hydrogels with different mesh sizes (ξ; mean ± s.d.; n = 4). The MSDM model (red solid line) predicts the existence and location of a local minimum and maximum in D/D₀, whereas free volume theory (black dashed line) and obstruction theory (black dotted line) do not. These local minima/maxima in D/D₀ are reflected in the experimental data.