Design, Fabrication, and Characterization of an Electrostatically Actuated Microfluidic Valve

Microfluidic device construction uses certain critical structures throughout many different applications. The valve structure remains one of the primary structures that present a barrier to miniaturization and portability. The extensive support devices required to power common microfluidic valves remove a significant amount of freedom from microfluidic device design. Moving to electrostatic methods of actuation could reduce the overall footprint of the microfluidic valve. This thesis covers three concept prototypes. Concept I presents an attempt at inlaying gold electrodes into polydimethylsiloxane substrates. Concept II attempts to use liquid silver injected into channels as electrode materials. Concept III uses aluminum sputtering to fabricate valve electrodes. Each device encountered complications during fabrication which led to improved fabrication guidelines for future devices. Designing and fabricating these concept devices required the development of several new processes in the clean room, including RIE Plasma bonding, PDMS sputtering techniques, and multilayer PDMS thin film fabrication. The PDMS sputtering technique in particular allows profilometry measurement of PDMS surfaces without risk of damaging the profilometer tip, a development that could allow for much more control over PDMS film thicknesses in future projects.