The initial structure for the concentrated NPs dispersions was prepared using the Packmol 55 software to arrange one NP and 1900 C4 or 1350 C8 ion pairs in a cubic box with a 4.3 nm edge. Those boxes were replicated 4 times in each cartesian direction rendering the compositions and sizes given in Table with an initial structure with each NP is distant from the closest neighbors by 8.6 nm (structure on the left of Figure ). The number of ion pairs was selected to result in the same concentration of NPs in both liquids, namely 0.0026 mol/L after relaxation. The simulations of a single NP used to characterize the solvent organization around the particle were prepared directly by packing the molecules using the Packmol software. For the initial structure used in the pmf calculations, the Themis software was used to locate the structure with minimum energy for a pair of NPs in contact (Figure ) by performing rigid-body rotations and translations of the two NPs and computing the interaction energy using the same parameters employed in the simulations. The dimer with the lowest energy was solvated with the ILs using Packmol. ** For the pmf calculations, the value given is the sum over every simulation performed to compute one pmf.