Experimental Verification of Overlimiting Current by Surface Conduction and Electro-Osmotic Flow in Microchannels
SCIE
SCOPUS
- Title
- Experimental Verification of Overlimiting Current by Surface Conduction and Electro-Osmotic Flow in Microchannels
- Authors
- Nam, S; Cho, I; Heo, J; Lim, G; Bazant, MZ; Moon, DJ; Sung, GY; Kim, SJ
- Date Issued
- 2015-03-16
- Publisher
- AMER PHYSICAL SOC
- Abstract
- Direct evidence is provided for the transition from surface conduction (SC) to electro-osmotic flow (EOF) above a critical channel depth (d) of a nanofluidic device. The dependence of the overlimiting conductance (OLC) on d is consistent with theoretical predictions, scaling as d(-1) for SC and d(4/5) for EOF with a minimum around d = 8 mu m. The propagation of transient deionization shocks is also visualized, revealing complex patterns of EOF vortices and unstable convection with increasing d. This unified picture of surface-driven OLC can guide further advances in electrokinetic theory, as well as engineering applications of ion concentration polarization in microfluidics and porous media.
- Keywords
- ION CONCENTRATION POLARIZATION; POROUS-MEDIA; MEMBRANE; CONVECTION; MODEL; ELECTRODIALYSIS; DESALINATION; INSTABILITY; NANOPORES; LAYER
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/13204
- DOI
- 10.1103/PHYSREVLETT.114.114501
- ISSN
- 0031-9007
- Article Type
- Article
- Citation
- PHYSICAL REVIEW LETTERS, vol. 114, no. 11, 2015-03-16
- Files in This Item:
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