Authors Hu, Y. ; Werner, C. ; Li, D.
Title Influence of the three-dimensional heterogeneous roughness on electrokinetic transport in microchannels
Date 24.11.2004
Number 12750
Abstract Surface roughness has been considered as a passive means of enhancing species mixing in electroosmotic flow through microfluidic systems. It is highly desirable to understand the synergetic effect of three-dimensional (3D) roughness and surface heterogeneity on the electrokinetic flow through microchannels. In this study, we developed a three-dimensional finite-volume-based numerical model to simulate electroosmotic transport in a slit microchannel (formed between two parallel plates) with numerous heterogeneous prismatic roughness elements arranged symmetrically and asymmetrically on the microchannel walls. We consider that all 3D prismatic rough elements have the same surface charge or zeta potential, the substrate (the microchannel wall) surface has a different zeta potential. The results showed that the rough channel's geometry and the electroosmotic mobility ratio of the roughness elements' surface to that of the substrate, var epsilonµ, have a dramatic influence on the induced-pressure field, the electroosmotic flow patterns, and the electroosmotic flow rate in the heterogeneous rough microchannels. The associated sample-species transport presents a tidal-wave-like concentration field at the intersection between four neighboring rough elements under low var epsilonµ values and has a concentration field similar to that of the smooth channels under high var epsilonµ values.
Publisher Journal of Colloid and Interface Science
Citation Journal of Colloid and Interface Science 280 (2004) 527-536

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