Estimation of zeta potential by electrokinetic analysis of ionic fluid flows through a divergent microchannel.

The streaming potential is generated by the electrokinetic flow effect within the electrical double layer of a charged solid surface. Surface charge properties are commonly quantified in terms of the zeta potential obtained by computation with the Helmholtz-Smoluchowski (H-S) equation following experimental measurement of streaming potential. In order to estimate a rigorous zeta potential for cone-shaped microchannel, the correct H-S equation is derived by applying the Debye-Hückel approximation and the fluid velocity of diverging flow on the specified position. The present computation provides a correction ratio relative to the H-S equation for straight cylindrical channel and enables us to interpret the effects of the channel geometry and the electrostatic interaction. The correction ratio decreases with increasing of diverging angle, which implies that smaller zeta potential is generated for larger diverging angle. The increase of Debye length also reduces the correction ratio due to the overlapping of the Debye length inside of the channel. It is evident that as the diverging angle of the channel goes to nearly zero, the correction ratio converges to the previous results for straight cylindrical channel.

[1]  Myung-Suk Chun,et al.  On the behavior of the electrostatic colloidal interaction in the membrane filtration of latex suspensions , 2001 .

[2]  Shuming Nie,et al.  Confinement and Detection of Single Molecules in Submicrometer Channels , 1997 .

[3]  W. Bowen,et al.  Electrokinetic effects in membrane pores and the determination of zeta-potential , 1998 .

[4]  R. J. Hunter,et al.  Zeta Potential in Colloid Science , 1981 .

[5]  A. Szymczyk,et al.  Streaming potential through multilayer membranes , 2001 .

[6]  J. Happel,et al.  Low Reynolds number hydrodynamics , 1965 .

[7]  M. Gad-el-Hak,et al.  Micro Flows: Fundamentals and Simulation , 2002 .

[8]  M. Nyström,et al.  Streaming potential as a tool in the characterization of ultrafiltration membranes , 1989 .

[9]  Norman Epstein,et al.  Theory of electrokinetic flow in fine cylindrical capillaries at high zeta-potentials , 1975 .

[10]  R. C. Furneaux,et al.  The formation of controlled-porosity membranes from anodically oxidized aluminium , 1989, Nature.

[11]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[12]  Szymczyk,et al.  Electrokinetic Phenomena in Homogeneous Cylindrical Pores. , 1999, Journal of colloid and interface science.

[13]  Yang,et al.  Electrokinetic Effects on Pressure-Driven Liquid Flows in Rectangular Microchannels , 1997, Journal of colloid and interface science.

[14]  John L. Anderson,et al.  Electrokinetic parameters for capillaries of different geometries , 1977 .

[15]  M. Guiver,et al.  Tangential flow streaming potential measurements : Hydrodynamic cell characterization and zeta potentials of carboxylated polysulfone membranes , 1998 .

[16]  Saulnier,et al.  A Convenient Apparatus to Determine the Zeta Potential of Grains by Electro-Osmosis. , 1999, Journal of colloid and interface science.

[17]  C. Causserand,et al.  Study of streaming potentials of clean and fouled ultrafiltration membranes , 1994 .

[18]  R. J. Hunter.  Zeta potential in colloid science : principles and applications , 1981 .

[19]  A. Fane,et al.  Evaluation of electroosmosis and streaming potential for measurement of electric charges of polymeric membranes , 1996 .

[20]  C. L. Rice,et al.  Electrokinetic Flow in a Narrow Cylindrical Capillary , 1965 .

[21]  A. Foissy,et al.  Use of electrophoretic mobility and streaming potential measurements to characterize electrokinetic properties of ultrafiltration and microfiltration membranes , 1998 .