Microscopic PIV measurements for electro-osmotic flows in PDMS microchannels

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.