Electroosmosis at inhomogeneous charged surfaces
Y. W. Kim; R. R. Netz; Y. W. Kim; Physik Department, TU München - 85748 Garching, Germany; R. R. Netz; Physik Department, TU München - 85748 Garching, Germany
Журнал:
EPL (Europhysics Letters)
Дата:
2005-12-01
Аннотация:
The Helmholtz-Smoluchowski (HS) relation between the local electrostatic potential and lateral solvent velocity in a continuum fluid at a planar charged surface under the action of a tangential electric field is exact for smooth surfaces, even in the presence of ion correlations. At rough surfaces, the interplay of hydrodynamics and surface friction due to electrostatic and excluded-volume interactions between surface groups and counterions gives rise to pronounced deviations from HS-theory. This is demonstrated by hydrodynamic simulations of ions at charged corrugated surfaces. Derived effective electrokinetic surface charges are highly reduced, in agreement with the experimental trend.
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