Scaling Behavior of Bipolar Nanopore Rectification with Multivalent Ions

Fertig, Dávid and Matejczyk, Bartlomiej and Valiskó, Mónika and Gillespie, Dirk and Boda, Dezső (2019) Scaling Behavior of Bipolar Nanopore Rectification with Multivalent Ions. The Journal of Physical Chemistry C, 123 (47). pp. 28985-28996. ISSN 0022-3654


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We present a scaling behavior of a rectifying bipolar nanopore as a function of the parameter ξ = R_P /(λz_if), where R_P is the radius of the pore, λ is the characteristic screening length of the electrolyte filling the pore, and z_if = \sqrt{z+|z− |} is a scaling factor that makes scaling work for electrolytes containing multivalent ions (z+ and z− are cation and the anion valences). By scaling we mean that the rectification of the pore (defined as the ratio of currents in the forward and reversed biased states) depends on pore radius, concentration, c, and ion valences via the parameter ξ implicitly. This feature is based on the fact that rectification depends on the voltage-sensitive appearance of depletion zones that, in turn, depend on the relation of RP to the rescaled screening length λz_if. In this modeling study, we use the Poisson-Nernst-Planck (PNP) theory and a particle simulation method, the Local Equilibrium Monte Carlo (LEMC). The latter can compute ion correlations that are ignored in the mean-field treatment of PNP and that are very important for multivalent ions (we show results for 1:1, 2:1, 3:1, and 2:2 electrolytes). In addition to the z_if factor, we show that one must choose a screening length appropriate to the system, in our case the Debye length for λ for PNP and the screening length given by the Mean Spherical Approximation for LEMC.

Item Type: Article
Subjects: Q Science / természettudomány > QC Physics / fizika > QC03 Heat. Thermodinamics / hőtan, termodinamika
Q Science / természettudomány > QD Chemistry / kémia > QD02 Physical chemistry / fizikai kémia
Depositing User: Professor Dezső Boda
Date Deposited: 10 Feb 2020 11:15
Last Modified: 10 Feb 2020 11:15

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