Macroion Attraction Due to Electrostatic Correlation between Screening Counterions. 1. Mobile Surface-Adsorbed Ions and Diffuse Ion Cloud

Abstract

Highly charged macroion surfaces in solutions of multivalent electrolytes attract each other electrostatically through correlations in their counterion environment. We show that significant correlation occurs when the counterion distribution has a pseudo-two-dimensional character. This allows us to treat the electrostatic correlation attraction semianalytically by reducing the problem to interaction between layers of adsorbed but mobile counterions neutralizing surfaces of similar charge density. Both when the counterion distribution is in the two-dimensional limit, and when it has a more realistic three-dimensional character, Coulomb repulsion between counterions produces an alternation of positive and negative charges at the surface. Two such apposing patterns adjust complementarily to each other, resulting in electrostatic attraction of the surfaces. The magnitude of this attraction depends solely on the surface charge density and the solution dielectric constant, while its range is defined by the size of the planar correlation hole around each ion. The attraction is stable with respect to the disruptive influence of planar thermal motion of the ions. The theory enables construction of a universal function which, after being scaled with the appropriate parameters of the system, yields the attractive electrostatic correlation pressure.

Ionic effects on the elasticity of single DNA molecules

“…However, an increase in DNA flexibility alone will not drive the collapse of DNA, since divalent cations do not produce this effect. Rather, the driving force for DNA collapse must also reside in the ability of a cation to reduce most, but not all, of the DNA phosphate charge while influencing helix hydration (32), helix secondary structure (33), and͞or electrostatic attractions through ion correlation (34,35).…”

On the fluid–fluid phase separation in charged-stabilized colloidal suspensions

“…For monovalent microions, Γ cc ∝ βq 2 /(ℓǫ) where ℓ is the characteristic mean distance between the microions in the double layer. If the number of condensed counterions is such as to almost completely neutralize the colloidal charge, which is the case for strongly charged colloids, ℓ ≃ a/ √ Z bare , and Γ cc becomes [22,29] When Γ cc exceeds unity, PB theory is expected to break down. The value Γ cc ≃ 2 has been reported to correspond to the instability threshold [29,31], which and has been observed in the simulations of Linse [6].…”

Correlation effects, image charge effects and finite size in the macro-ion-electrolyte system: A field-theoretic approach

“…Same charge attraction describes a situation in which two macro-ions of the same charge are able to attract each other through interactions with their counterions. Notably, both these phenomena have been predicted in the case of strong correlations between ions at the macro-ion surface [7,6,25], where it is supposed that a Wigner crystal forms on the surface of each macro-ion. Here, the mechanism of attraction is that a Wigner crystal on one macro-ion interlocks with the Wigner crystal on another macro-ion, so that the positive charges associated with one macro-ion lie close to the negative regions on the other and vice versa [6,25].…”

“…Correlation effects may lead to two predicted phenomena, that of charge inversion [1,7,23,24] and samecharge attraction [1,3,5,7,9,11,25]. In charge inversion, the amount of positive charge, due to counter-ions, exceeds the surface charge density of the macro-ion effectively making it of opposite charge to its fixed charged groups.…”