In addition, to provide a finer insight into the relative reactivities of the two substrates, we calculated the local reactivity indices for each atom forming the eight ester groups of the two oligomers (𝑘 = C, O' and O'', ) electron density, and they depend on a global descriptor (𝜔) and the condensed Fukui functions (𝑓), as detailed in the Computational Methods section. The atomic populations for the nucleophilic (𝑓 + ) and electrophilic (𝑓 -) Fukui functions were calculated at the B3LYP/def2-TZVP level using four different atomic population schemes: Mulliken, ChelpG, Hirshfeld, and the minimal basis iterative stockholder (MBIS). In Figure , we present the results obtained for C5, O5', and O5'' atoms for PET4 (panel A) and PEF4 (panel B), as these atoms form the ester group hydrolyzed during the WTMD simulations. To illustrate the variation between the two substrates, we used uniformly continuous lines for 𝜔 and dashed lines for 𝑁 6 (Figure ). The results indicate that the 𝜔 6 8