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Beyond the Tradeoff: Dynamic Selectivity in Ionic Transport and Current Rectification
- Source :
- Journal of Physical Chemistry B, Journal of Physical Chemistry B, American Chemical Society, 2019, 123 (5), pp.1171-1185. ⟨10.1021/acs.jpcb.8b11202⟩, The Journal of Physical Chemistry B
- Publication Year :
- 2019
- Publisher :
- HAL CCSD, 2019.
-
Abstract
- Traditionally, ion selectivity in nanopores and nanoporous membranes is understood to be a consequence of Debye overlap, in which the Debye screening length is comparable to the nanopore radius somewhere along the length of the nanopore(s). This criterion sets a significant limitation on the size of ion-selective nanopores, as the Debye length is on the order of 1-10 nm for typical ionic concentrations. However, the analytical results we present here demonstrate that surface conductance generates a dynamical selectivity in ion transport, and this selectivity is controlled by so-called Dukhin, rather than Debye, overlap. The Dukhin length, defined as the ratio of surface to bulk conductance, reaches values of hundreds of nanometers for typical surface charge densities and ionic concentrations, suggesting the possibility of designing large-nanopore (10-100 nm), high-conductance membranes exhibiting significant ion selectivity. Such membranes would have potentially dramatic implications for the efficiency of osmotic energy conversion and separation techniques. Furthermore, we demonstrate that this mechanism of dynamic selectivity leads ultimately to the rectification of ionic current, rationalizing previous studies, showing that Debye overlap is not a necessary condition for the occurrence of rectifying behavior in nanopores.
- Subjects :
- Materials science
Ionic bonding
010402 general chemistry
7. Clean energy
01 natural sciences
Quantitative Biology::Subcellular Processes
symbols.namesake
0103 physical sciences
Materials Chemistry
Surface charge
Physical and Theoretical Chemistry
[PHYS.COND]Physics [physics]/Condensed Matter [cond-mat]
Debye length
ComputingMilieux_MISCELLANEOUS
Debye
[PHYS]Physics [physics]
Physics::Biological Physics
010304 chemical physics
Conductance
0104 chemical sciences
Surfaces, Coatings and Films
Nanopore
Membrane
Chemical physics
symbols
Selectivity
[PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Subjects
Details
- Language :
- English
- ISSN :
- 15206106 and 15205207
- Database :
- OpenAIRE
- Journal :
- Journal of Physical Chemistry B, Journal of Physical Chemistry B, American Chemical Society, 2019, 123 (5), pp.1171-1185. ⟨10.1021/acs.jpcb.8b11202⟩, The Journal of Physical Chemistry B
- Accession number :
- edsair.doi.dedup.....84f36ea6724b5403250240452e7df1bb