Microscopic PIV Measurements for Electro-osmotic Flows in PDMS Microchannels

Article type: Research Article

Authors: Kim, M.J. | Kihm, K.D.

Affiliations: Division of Engineering, Brown University, Box D 182 Hope St., Providence, RI 02912, U.S.A. E-mail: Minjun_Kim@Brown.edu | Department of Mechanical Engineering, Texas A&M University, College Station, TX 77843, U.S.A.

Abstract: Electro-osmosis is the flow produced by the action of an electric field on a fluid with a net charge, which is created by the Zeta potential and confined in the Debye layer. This basic phenomenon in the electro-kinetic transport plays an important role in the microfluidic systems being explored today because it can be applied to a variety of MEMS devices. This paper presents global and point-wise comparisons of experimental measurements of electro-osmotically driven flows in elementary microchannel configurations, which are made by photolithography using poly-di-methyl-siloxane (PDMS). To measure full field velocity distributions in PDMS microchannels, a microscopic particle image velocimetry (μ-PIV) system has been developed to track the fluorescent images of 500 nm diameter particles. Comparisons of experimental results among various micro-configurations show feasibilities of the electro-osmotic flows to use for micro-pumping and micro-fluidic flow control.

Keywords: electro-osmotic flow, μ-PIV, microchannel, fluorescent micro-spheres

Journal: Journal of Visualization, vol. 7, no. 2, pp. 111-118, 2004