Nonlinear ion transport mediated by induced charge in ultrathin nanoporous membranes
Journal Article
·
· Physical Review. E
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); OSTI
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Ultrathin membranes with nanoporous conduits show promise for ionic separations and desalination applications, but the mechanisms underlying the nonlinear ionic transport observed in these systems are not well understood. Here, in this work, we demonstrate how induced charge at membrane interfaces can lead to nonlinear ionic transport and voltage-dependent conductance through such channels. The application of an electric field on a polarizable membrane leads to induced charges at the membrane interfaces. The induced charges in turn are screened by diffuse charges in the electrolyte, which are acted upon by the electric field. For extremely thin membranes, the induced charge effect can be significant even for moderate applied voltages commonly used in experiments. We apply a continuum Poisson-Nernst-Planck model to characterize the current-voltage behavior of ultrathin membranes over a wide parameter space. The predictions of the model are compared to recent experiments on graphene and MoS2 membranes in an electric field. We expect the role of induced charge to be especially pronounced in the limit of atomically thin membranes.
- Research Organization:
- Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- SC0019112
- OSTI ID:
- 1980195
- Journal Information:
- Physical Review. E, Journal Name: Physical Review. E Journal Issue: 4 Vol. 104; ISSN 2470-0045
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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