Structure of spherical electric double layers: a density functional approach.

Area of Science:

• Physical Chemistry
• Colloid Science
• Computational Physics

Background:

• Electric double layers are crucial in colloid science, influencing stability and interactions.
• Understanding ion distribution near charged surfaces is key to predicting macroscopic behavior.

Purpose of the Study:

• To develop a novel density functional theory (DFT) for spherical electric double layers.
• To model macroion-solvation interactions within the restricted primitive model.

Main Methods:

• A partially perturbative DFT approach was employed.
• Hard-sphere contributions were calculated using averaged weighted density.
• Ionic contributions were derived from a second-order functional Taylor expansion.

Main Results:

• The DFT quantitatively matches Monte Carlo simulations for density profiles and zeta potentials.
• The theory is valid across diverse macroion sizes and electrolyte concentrations.
• Observed agreement validates the theoretical framework.

Conclusions:

• The developed DFT provides accurate predictions for electric double layer structures.
• The theory reveals insights into interfacial layering and charge inversion phenomena.
• This work advances theoretical understanding of charged interfaces.