Platinum microelectrodes become essential components in microfluidic devices for separation, pumping, sensing, and other bio-analyses. Due to their chemical inertness, several research groups have developed microfluidic devices with integrated platinum electrodes on silicon, quartz, or glass substrates. However, no techniques have been reported so far for depositing platinum electrodes in polymeric microchannels. In this study, a novel fabrication scheme for forming integrated microelectrodes in a poly-dimethyl-siloxane (PDMS) microchip is described. The electrode fabrication technique consists of photolithography, thermal processing, sequential sputtering of titanium and platinum and stripping off photoresist, while soft-lithography is used to form the microfluidic channels on PDMS. This approach facilitates precise positioning of the electrodes with a micron-sized gap between them, and it can be used for both low and high aspect ratio channels. The platinum electrodes, formed on the PDMS channel surface, demonstrated very good interfacial adhesion with the substrate due to the use of a very thin titanium layer between the platinum and PDMS. The surface roughness of the electrodes was found around ±50 nm.

Volume Subject Area:
Microelectromechanical Systems
Topics:
Manufacturing, Microfluidics, Platinum, Electrodes, Plasma desorption mass spectrometry, Titanium, Adhesion, Glass, Integrated circuits, Lithography, Microchannels, Photolithography, Photoresists, Quartz, Separation (Technology), Silicon, Siloxanes, Sputtering (Irradiation), Surface roughness
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