Back to Search
Start Over
Electrically driven flow near a colloidal particle close to an electrode with a Faradaic current
- Source :
- Langmuir : the ACS journal of surfaces and colloids. 23(7)
- Publication Year :
- 2007
-
Abstract
- To elucidate the nature of processes involved in electrically driven particle aggregation in steady fields, flows near a charged spherical colloidal particle next to an electrode were studied. Electrical body forces in diffuse layers near the electrode and the particle surface drive an axisymmetric flow with two components. One is electroosmotic flow (EOF) driven by the action of the applied field on the equilibrium diffuse charge layer near the particle. The other is electrohydrodynamic (EHD) flow arising from the action of the applied field on charge induced in the electrode polarization layer. The EOF component is proportional to the current density and the particle surface (zeta) potential, whereas our scaling analysis shows that the EHD component scales as the product of the current density and applied potential. Under certain conditions, both flows are directed toward the particle, and a superposition of flows from two nearby particles provides a mechanism for aggregation. Analytical calculations of the two flow fields in the limits of infinitesimal double layers and slowly varying current indicate that the EOF and EHD flow are of comparable magnitude near the particle whereas in the far field the EHD flow along the electrode is predominant. Moreover, the dependence of EHD flow on the applied potential provides a possible explanation for the increased variability in aggregation velocities observed at higher field strengths.
- Subjects :
- Faradaic current
Chemistry
Near and far field
Surfaces and Interfaces
Condensed Matter Physics
Molecular physics
Charged particle
Particle aggregation
Classical mechanics
Electrode
Electrochemistry
General Materials Science
Electrohydrodynamics
Polarization (electrochemistry)
Current density
Spectroscopy
Subjects
Details
- ISSN :
- 07437463
- Volume :
- 23
- Issue :
- 7
- Database :
- OpenAIRE
- Journal :
- Langmuir : the ACS journal of surfaces and colloids
- Accession number :
- edsair.doi.dedup.....dee6ad923d32c3225278ac646d99d635