To better understand the dynamics and electronic properties, we performed simulations of our amorphous PET slab model in vacuum and in water (Figure ). We calculated the induced dipole moment by subtracting the permanent dipole moment from the total dipole moment of each PET residue in the slab and binned them based on the z-axis coordinate of their centers-of-mass. As shown in Figure , the induced dipole distribution at the center of the slab is close to zero in both systems, most likely reflecting the cancellation on average of polarization influences due to the unorganized structure of an amorphous phase. Interestingly, the induced dipole moments in vacuum trended towards slightly negative values at slab-vacuum interface (|Z| > 25 Å), reaching approximately -1 D in the most exposed monomers (Figure ). These results are consistent with the dipole moment decomposition for model compounds shown in Table , suggesting that PET residues tend to depolarize when exposed to vacuum conditions.