title: Switchable Hydrophobic Valve for Controlled Microfluidic Processing.
abstract: A simple microfluidic valve, without any moving parts, is presented that can control solution flow on demand in microchannels of many different materials using a low-power electric signal. Many independently operating valves can easily be integrated into complex microfluidic systems. The valve consists of a self-assembled monolayer (SAM) formed on a platinum electrode that is incorporated directly in the microchannel. The normally-on valve stops the solution flow due to a hydrophobic SAM on the electrode surface. The solution is allowed to pass the valve by applying a potential to the electrode, which removes the SAM due to reductive desorption. The valve operation is highly stable and has switching times of the order of 1 s. The valve is ideal for controlled solution manipulation in integrated micro-analytical systems and autonomous microfluidic systems.
authors.affiliation: Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8573, Japan.
authors.forename: Gokul Chandra
authors.initials: GC
authors.lastname: Biswas
authors.affiliation: Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8573, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8573, Japan.
authors.forename: Edwin T
authors.initials: ET
authors.lastname: Carlen
authors.affiliation: Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8573, Japan.
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Yokokawa
authors.affiliation: Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, 305-8573, Japan. hsuzuki@ims.tsukuba.ac.jp.
authors.forename: Hiroaki
authors.identifier: http://orcid.org/0000-0002-3535-703X
authors.initials: H
authors.lastname: Suzuki
keywords: electrochemical desorption; lab on a chip; microfluidics; platinum; self-assembled monolayers