Ion binding in polyelectrolyte solutions. An account for noncoulombic interactions

Abstract

Canonical Monte Carlo method is used to study a refined model of polyelectrolyte solution. The discrete charges on a polyion are located periodically along the helix. The ion‐ion and ion‐polyion interactions are described by a solvent‐averaged potential which accounts for the desolvation of ions. The major parameters of the short‐range potential function are Gurney coefficients for the counterion‐counterion (Acc) and the charged group‐counterion interaction (Apc). From simulations, the self‐diffusion coefficient for counterions, D/Do, was calculated. This quantity is rather sensitive to the value of Apc and much less to the choice of the counterion‐counterion coefficient. The refined model is used to analyze a fraction of apparently free counterions, α (≈D/D0), as obtained from recent measurements of transport properties in aqueous solutions of lithium and cesium poly(styrenesulfonate). The values of Gurney parameters, which fit experimental results, are determined: for a good agreement with experimental data an additional repulsive interaction Apc≈3900 J/mol is required for lithium poly(styrenesulfonate) at 5°C. This value is smaller (≈1500 J/mol) for lithium salt at 35°C, and negative, ≈−130 J/mol, for cesium salt of poly(styrenesulfonic) acid.

Osmotic Properties of Aqueous Ionene Solutions

“…Further, they neglect the effect of specific interactions, treating the solution as a purely Coulombic fluid, where the charges are embedded in a dielectric continuum. There are a few exceptions in this respect, , for example, Jayaram and Beveridge 19 used a modified model that included a Gurney correction term for desolvation , to interpret the experimental data. In a similar study, Rebolj et al used the Gurney model to analyze the experimental results for ion binding in lithium and cesium poly(styrenesulfonate) solutions at various temperatures.…”

“…Only Coulombic interactions were included in this computation. Finally, in the third model the counterion−counterion and the fixed charge−counterion interactions are modeled using the interaction potential of Ramanathan and Friedman 22 to account for solvation phenomena . The canonical Monte Carlo method was utilized to obtain numerical results for the discrete-charge models. − …”

Polyelectrolyte hydration: Theory and experiment

“…Negative deviations are more difficult to capture quantitatively and the simplest way seems to by invoking the non-Coulombic counterion-polyion attraction [61]. Attempts have also been made [52,53] to explain the disagreement between theory and experiment for some other properties by augmenting the cylindrical cell model with an additional short-range potential between the polyions and counterions.…”

“…It can correctly predict the concentration dependence of the osmotic coefficients (see, e.g., ref. [4]), as well as some transport and other properties [51][52][53]. Due to the shortcomings of the Poisson-Boltzmann equation, which ignores ion-ion correlations, this approach is less successful for divalent counterions [38][39][40][41][42].…”

Influences of co‐monomers and electrolyte acidity on morphological structure of copper‐in‐copolymer gradient film

“…Obviously, chemical and physical interactions among polymer groups and metal ions in SCF affect the ion transport. From this point of view, the ion transport in SCF is similar to lithium ion motion in polymer electrolyte in rechargeable lithium batteries 11–13. On the other hand, electrochemical conditions like a voltage drop in the SCF are important influencing factors on ion transport.…”