Finally, driven by the difference in interaction energies, we calculated the electrostatic potential at the PET film surface when bound to the hevein protein. As shown in Figure , the PET residues bound to the hevein were polarized, increasing the electrostatic potential at the PET surface directly in contact with the protein. This increase is clearly demonstrated in Figure by the positive shift of the electrostatic potential distribution in the system bound to the hevein protein relative to the PET crystal film in water (Figure ). These results suggest that electrostatic interactions between PET crystal films and CBMs could be further explored to design better PET-binding modules.