For each of the systems, we used the last frame of production simulation and relaxed the Drude oscillators via energy minimization in CHARMM, as described above for Drude conversion. We then generated the Connolly surface of the PET molecules (either amorphous slab or crystal array) using the MSMS software with a probe radius of 1.5 Å. Finally, we calculated the electrostatic potential (V (r p )) exerted by PET residues at each vertex of the Connolly surface (r p ) defined by MSMS according to Equation :