On the nature of overcharging and charge inversion in electrical double layers

Abstract

Understanding overcharging and charge inversion is one of the long-standing challenges in soft matter and biophysics. To study these phenomena, we employ the modified Gaussian renormalized fluctuation theory, which allows for the self-consistent accounting of spatially varying ionic strength, as well as the spatial variations in dielectric permittivity and excluded volume effects. The underlying dependence of overcharging on the electrostatic coupling is elucidated by varying surface charge, counterion valency, and dielectric contrast. Consistent with simulations, three characteristic regimes corresponding to weak, moderate, and strong coupling are identified. Important features like the inversion of zeta potential, crowding and ionic layering at the surface are successfully captured. For weak coupling, there is no overcharging. In the moderate coupling regime, overcharging increases with surface charge. Finally, in the strong coupling regime, ionic crowding and saturation in overcharging are observed. Our theory predicts non-monotonic dependence of charge inversion on multivalent salt concentration as well as the addition of monovalent salt, in quantitative agreement with experiments.

References in corpus (9)

• Salt-induced collapse and reexpansion of highly charged flexible polyelectrolytes
• Interfacial layering in the electric double layer of ionic liquids
• 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
• Colloidal charge reversal: Dependence on the ionic size and the electrolyte concentration
• Electrostatic correlation induced ion condensation and charge inversion in multivalent electrolytes
• Ionic current inversion in pressure-driven polymer translocation through nanopores
• Self-Consistent Description of Vapor-Liquid Interface in Ionic Fluids
• Ion correlation driven like-charge attraction in multivalent salt solutions

Cited by in corpus (5)

• 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
• Electric Fields Near Undulating Dielectric Membranes
• Understanding long-range opposite charge repulsion in multivalent salt solutions