Electrostatic correlations on the ionic selectivity of cylindrical membrane nanopores

We characterize the role of electrostatic fluctuations on the charge selectivity of cylindrical nanopores confining electrolyte mixtures. To this end, we develop an extended one-loop theory that can account for correlation effects induced by the surface charge, nanoconfinement of the electrolyte, an...

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Bibliographic Details
Published in:The Journal of chemical physics 2014-02, Vol.140 (6), p.064701-064701
Main Authors: Buyukdagli, Sahin, Ala-Nissila, T
Format: Article
Language:English
Subjects:
Calcium chloride
Computer simulation
Confining
Correlation
Deoxyribonucleic acid
Divalent cations
DNA
Electrolytes
Electrolytes - chemistry
Ions - chemistry
Membranes, Artificial
Monte Carlo Method
Monte Carlo simulation
Nanofiltration
Nanopores - ultrastructure
Permittivity
Porosity
Selectivity
Static Electricity
Surface charge
Variation
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Summary:We characterize the role of electrostatic fluctuations on the charge selectivity of cylindrical nanopores confining electrolyte mixtures. To this end, we develop an extended one-loop theory that can account for correlation effects induced by the surface charge, nanoconfinement of the electrolyte, and interfacial polarization charges associated with the low permittivity membrane. We validate the quantitative accuracy of the theory by comparisons with previously obtained Monte-Carlo simulation data from the literature, and scrutinize in detail the underlying forces driving the ionic selectivity of the nanopore. In the biologically relevant case of electrolytes with divalent cations such as CaCl2 in negatively charged nanopores, electrostatic correlations associated with the dense counterion layer in the channel result in an increase of the pore coion density with the surface charge. This peculiarity analogous to the charge inversion phenomenon remains intact for dielectrically inhomogeneous pores, which indicates that the effect should be observable in nanofiltration membranes or DNA-blocked nanopores characterized by a low membrane permittivity. Our results show that a quantitatively accurate consideration of correlation effects is necessary to determine the ionic selectivity of nanopores in the presence of electrolytes with multivalent counterions.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.4864323