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Generation and Control of Electrohydrodynamic Flows in Aqueous Electrolyte Solutions
Published on: September 7, 2018
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Electrohydrodynamics near hydrophobic surfaces.
S R Maduar1,2, A V Belyaev1,2,3,4, V Lobaskin5
1A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, 31 Leninsky Prospect, 119071 Moscow, Russia.
Physical Review Letters
|April 4, 2015
Summary
Electro-osmotic flow near hydrophobic surfaces is significantly influenced by surface charge mobility. New electrohydrodynamic boundary conditions are proposed for accurate electro-osmotic flow quantification.
Area of Science:
- Fluid dynamics
- Surface science
- Electrochemistry
Background:
- Electro-osmotic flow (EOF) is crucial in microfluidic devices.
- Hydrophobic surfaces exhibit unique fluid behavior due to surface properties.
- Understanding surface charge dynamics is key to controlling EOF.
Purpose of the Study:
- To investigate the impact of surface charge mobility on EOF near hydrophobic surfaces.
- To develop accurate electrohydrodynamic boundary conditions for slipping interfaces.
- To re-evaluate the concept of zeta potential for hydrophobic surfaces.
Main Methods:
- Theoretical formulation of electrohydrodynamic boundary conditions.
- Dissipative particle dynamics (DPD) simulations with explicit charges.
- Analysis of fluid transport and shear stress at the interface.
Main Results:
- EOF strongly depends on surface charge mobility.
- Hydrodynamic slippage amplifies fluid transport for immobile charges.
- Mobile charges introduce an additional electric force, increasing shear stress.
- Proposed electrohydrodynamic boundary conditions accurately predict simulation results.
Conclusions:
- Surface charge mobility is a critical factor in EOF near hydrophobic surfaces.
- Existing hydrodynamic boundary conditions are insufficient for mobile surface charges.
- The study provides a new framework for understanding zeta potential on hydrophobic surfaces.
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