Interaction between charged nanoparticles in deionized suspensions

We develop a theoretical framework to calculate the interaction potential between charged nanoparticles in monovalent deionized suspensions. The approach is based on the renormalized Jellium (rJellium) model, which provides the effective charge governing the far-field behavior of the Derjaguin, Landau, Verwey, and Overbeek (DLVO) potential. For short interparticle separations, we combine rJellium with the modified Derjaguin approximation, explicitly accounting for local violations of charge neutrality while imposing a constant-charge boundary condition on the Derjaguin surfaces. The theoretical predictions are systematically compared with Monte Carlo simulations, where the infinite system size is treated using Ewald summation. We find excellent quantitative agreement across all separations, surface charge densities, colloidal volume fractions, and particle sizes-without any adjustable parameters.