Disjoining Pressure of an Electrolyte Film Confined between Semipermeable Membranes

Salim R. Maduar; Olga I. Vinogradova

doi:10.1063/1.4892758

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arXiv · 1311.1471

Disjoining Pressure of an Electrolyte Film Confined between Semipermeable Membranes

Salim R. Maduar·Olga I. Vinogradova

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Abstract

We consider an electrolyte solution confined by semipermeable membranes in contact with a salt-free solvent. Membranes are uncharged, but since small counter-ions leak-out into infinite salt-free reservoirs, we observe a distance-dependent membrane potential, which generates a repulsive electrostatic disjoining pressure. We obtain the distribution of the potential and of ions, and derive explicit formulas for the disjoining pressure, which are validated by computer simulations. We predict a strong short-range power-law repulsion, and a weaker long-range exponential decay. Our results also demonstrate that an interaction between membranes does strongly depend on the screening lengths, valency of an electrolyte solution, and an inter-membrane film thickness. Finally, our analysis can be directly extended to the study of more complex situations and some biological problems.

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Salim R. Maduar, Olga I. Vinogradova. 2014-07-29. Disjoining Pressure of an Electrolyte Film Confined between Semipermeable Membranes. https://doi.org/10.1063/1.4892758

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