Ju-Hee So and Michael Dickey from North Carolina State University present an extremely simple fabrication route for microfluidic electrodes by using metal alloys with low melting point , such as eutectic gallium indium.
The liquid metal injected into the microchannels is inherently aligned and in direct contact with the fluid, but is neatly prevented from mixing with the fluid by posts with spacings that are too small to allow the metal to easily flow through. The metal also maintains its shape despite being a liquid, due to the spontaneous formation of a thick oxide skin. The mechanical stability of the electrodes was demonstrated in operating conditions commonly used in microfluidic applications, and as a proof-of-principle, used for electrohydrodynamic mixing, which requires extremely high electric fields.
The authors believe that this technique is significantly simpler and easier to implement than anything that has been published to date in the literature – why not download the article and see for yourself? The article is free to access for 4 weeks!
Inherently aligned microfluidic electrodes composed of liquid metal
Ju-Hee So and Michael D. Dickey
Lab Chip, 2011, 11, 905-911