Ion association at discretely-charged dielectric interfaces: Giant charge inversion

Abstract

Giant charge reversal has been identified for the first time by Monte Carlo simulation for a discretely charged surface in contact with a trivalent electrolyte solution. It takes place regardless of the surface charge density under study and the monovalent salt. In stark contrast to earlier predictions based on the 2-dimensional Wigner crystal model to describe strong correlation of counterions at the macroion surface, we find that giant charge reversal reflects an intricate interplay of ionic volume effects, electrostatic correlations, surface charge heterogeneity, and the dielectric response of the confined fluids. While the novel phenomenon is yet to be confirmed with experiment, the simulation results appear in excellent agreement with a wide range of existing observations in the subregime of charge inversion. Our findings may have far-reaching implications to understanding complex electrochemical phenomena entailing ionic fluids under dielectric confinements.

Nanopore charge inversion and current-voltage curves in mixtures of asymmetric electrolytes

“…Charge inversion constitutes a subject of current interest for both fundamental and applied research [1,14,15]. Theoretically, this effect can be studied by means of computer simulations and physical models based on strongly correlated liquids of multivalent ions in the vicinity of a charged surface [1,[16][17][18][19].…”

Simulations of Coulomb systems confined by polarizable surfaces using periodic Green functions

“…This notwithstanding, there are many important systems with a broken symmetry: ionic liquids at electrified interfaces [12][13][14][15][16][17] , charged nanopores [18][19][20] , nanoconfined electrolytes [21][22][23] , just to cite a handful of examples. These systems can present new phenomena, such as like-charged attraction [24][25][26][27] and charge reversal [28][29][30] , which are hard to describe analytically 31 , hence the importance of fast simulation methods. To overcome the difficulty of using 2d Ewald summation, a number of approaches have attempted to extend the efficient 3d Ewald summation method to systems with slab geometry 22,[32][33][34] .…”

Size and charge correlations in spherical electric double layers: a case study with fully asymmetric mixed electrolytes within the solvent primitive model

“…However, due to the presence of three Helmholtz planes, the dielectric constant should not be the same everywhere. 43 Extension of the same model to include image charges will be considered in the next study. The off-centric charge on the small ions will be a simple extension of the current study.…”

“…1 to be noted here that with this single dielectric constant (78.5), the effects due to image charges are completely ignored, which may not be an exact situation considering different Stern layers formed due to the unequal size of the small ions. 43 The interaction potential between any two components (a and b) of the electrolyte solution is given as…”