Electrostatic correlation induced ion condensation and charge inversion in multivalent electrolytes

Abstract

The study of the electrical double layer lies at the heart of colloidal and interfacial science. The standard mean-field Poisson-Boltzmann (PB) theory is incapable of modeling many phenomena originated from ion correlation. An important example is charge inversion or overcharging of electrical double layers in multivalent electrolyte solutions. Existing theories aiming to include correlations cannot capture the nonmonotonic dependence of charge inversion on salt concentration because they have not systematically accounted for the inhomogeneous nature of correlations from surface to the bulk and the excluded volume effect of ions and solvent molecules. In this work, we modify the Gaussian renormalized fluctuation theory by including the excluded volume effect to study ion condensation and charge inversion. A boundary layer approach is developed to accurately model the giant difference in ion correlations between the condensed layer near the surface and the diffuse layer outside. The theory is used to study charge inversion in multivalent electrolytes and their mixtures. We predict a surface charge induced formation of a three-dimensional condensed layer, which is necessary but not sufficient for charge inversion. The value of the effective surface potential is found to depend non-monotonically on the bulk salt concentration. Our results also show a non-monotonic reduction in charge inversion in monovalent and multivalent electrolyte mixtures. Our work is the first to qualitatively reproduce experimental and simulation observations and explains the underlying physics.

References in corpus (8)

• Salt-induced collapse and reexpansion of highly charged flexible polyelectrolytes
• Interfacial layering in the electric double layer of ionic liquids
• Charge Oscillations in Ionic Liquids: A Microscopic Cluster Model
• Overcharging, charge inversion and reentrant condensation: Using highly-charged polyelectrolytes in tetravalent salt solutions as an example of study
• On the theoretical description of weakly charged surfaces
• Simulation of charge reversal in salty environments: Giant overcharging?
• Self-energy-modified Poisson-Nernst-Planck equations: WKB approximation and finite-difference approaches
• Ion pairing in model electrolytes: A study via three particle correlation functions

Cited by in corpus (6)

• On the nature of overcharging and charge inversion in electrical double layers
• Self-Consistent Description of Vapor-Liquid Interface in Ionic Fluids
• Ion correlation driven like-charge attraction in multivalent salt solutions
• Electrostatic Correlation Augmented Self-Consistent Field Theory and Its Application to Polyelectrolyte Brushes
• Ion Correlation-Driven Hysteretic Adhesion and Repulsion between Opposing Polyelectrolyte Brushes
• Microphase Segregation in Polyelectrolyte Brushes