Sarkadi, Zsófia and Fertig, Dávid and Ható, Zoltán and Valiskó, Mónika and Boda, Dezső (2021) From nanotubes to nanoholes: Scaling of selectivity in uniformly charged nanopores through the Dukhin number for 1:1 electrolytes. JOURNAL OF CHEMICAL PHYSICS, 154 (15). No154704. ISSN 00219606

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Abstract
Scaling of the behavior of a nanodevice means that the device function (selectivity) is a unique smooth and monotonic function of a scaling parameter that is an appropriate combination of the system’s parameters. For the uniformly charged cylindrical nanopore studied here, these parameters are the electrolyte concentration, c, voltage, U, the radius and the length of the nanopore, R and H, and the surface charge density on the nanopore’s surface, σ. Due to the nonlinear dependence of selectivities on these parameters, scaling can only be applied in certain limits. We show that the Dukhin number, Du = ∣σ∣/eRc ∼ ∣σ∣λ 2D /eR (λ D is the Debye length), is an appropriate scaling parameter in the nanotube limit (H → ∞). Decreasing the length of the nanopore, namely, approaching the nanohole limit (H → 0), an alternative scaling parameter has been obtained, which contains the pore length and is called the modified Dukhin number: mDu ∼ Du H/λ D ∼ σλ D H/eR. We found that the reason for nonlinearity is that the double layers accumulating at the pore wall in the radial dimension correlate with the double layers accumulating at the entrances of the pore near the membrane on the two sides. Our modeling study using the Local Equilibrium Monte Carlo method and the Poisson–Nernst–Planck theory provides concentration, flux, and selectivity profiles that show whether the surface or the volume conduction dominates in a given region of the nanopore for a given combination of the variables. We propose that the inflection point of the scaling curve may be used to characterize the transition point between the surface and volume conductions.
Item Type:  Article 

Subjects:  Q Science / természettudomány > QC Physics / fizika > QC03 Heat. Thermodinamics / hőtan, termodinamika Q Science / természettudomány > QC Physics / fizika > QC06 Physics of condensed matter / szilárdtestfizika Q Science / természettudomány > QD Chemistry / kémia > QD02 Physical chemistry / fizikai kémia 
Depositing User:  Professor Dezső Boda 
Date Deposited:  09 Nov 2023 15:01 
Last Modified:  09 Nov 2023 15:01 
URI:  http://real.mtak.hu/id/eprint/179441 
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