A general model based on the Onsager reciprocal relations is developed to study the streaming potential and streaming current in heterogeneous microchannels. The surface heterogeneities may be symmetrically or asymmetrically distributed parallel or perpendicular to the flow axis. Both streaming effects are modified by the flow rate through the heterogeneous channel, to eliminate the possible influence of electrokinetic flow on the streaming potential and streaming current measurements. Although they are still dependent on the distribution of surface heterogeneity, the flow rate-modified streaming effects are demonstrated to provide more consistent results with the traditional linear assumption than do the traditional ones, especially apparent in small microchannels.
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Acknowledgments Financial support from Clemson University through a start-up package and a Research Investment Initiative Fund to X.X. is gratefully acknowledged.
Copyright 2008 Elsevier B.V., All rights reserved.
- Flow rate
- Heterogeneous microchannel
- Onsager reciprocal relations
- Streaming current
- Streaming potential