An automated, high-throughput experimental system for induced charge electrokinetics.

Abstract

Recent experiments in induced charge electrokinetics (ICEK) have shown that the standard theory generally overpredicts experimentally observed velocities. Such discrepancies reduce the efficacy of practical ICEK devices, and highlight our incomplete understanding of electrokinetic phenomena. Here, we present an automated experimental system that allows for the rapid collection of ICEK data under a variety of conditions ( approximately 1000 per day) to help develop and constrain new theories. We demonstrate this system by studying the ICEK slip flows over electrodes that have been controllably "contaminated" with a dielectric layer, either SiO(2) or an alkanethiol self-assembled monolayer, of known thickness. We also develop a theory that accounts for the effects of the dielectric coatings surface chemistry that yields quantitative agreement with experiments over nearly a thousand distinct conditions in the SiO(2) system and present an additional three thousand experiments of flows over alkanethiol monolayers. Our experimental system allows the direct interrogation of the physico-chemical effects that influence ICEK flows and for the optimization of these flows in lab-on-a-chip systems.