Both dispersions present a secondary g(r) maximum, but with different shapes, intensities and positions. For the hydrophobic particle, the position slightly after 6 nm is consistent with 2 NPs separated by a solvent layer and matches the end of the free energy barrier noticed on the respective pmf (Figure ). A similar peak due to NPs separated by a solvent layer is also noticed for both NPs in C8, however, for the hydrophilic particle in C4 the solvent layers are ill-defined and there is no significative barrier for the dimer association, which explains the absence of the maximum separated by a solvent layer around 6.0 nm. On the other hand, there is a broad maximum around 9.0 nm, which is nearly 4 times the radius of the NP and corresponds to the distance between second neighbors in the cluster formed if the angle between three bonded NPs is close to 180⁰. The broadness of this maxima, however, indicate that the cluster formed isn't much structured beyond the first neighbors around each particle.