Publications

Etching of indium tin oxide (ITO) thin films in high density chlorine plasmas is studied, with the goal of increasing the etching selectivity to photoresist. The ITO etching rate increases with ethylene addition, but is not affected by BCl3 addition. ITO exhibits a threshold energy for ion etching, whereas the...

We report on the development of sub-millimeter size adaptive liquid microlenses and microlens arrays using two immiscible liquids to form individual lenses. Microlenses and microlens arrays having aperture diameters as small as 50 microns were fabricated on a planar quartz substrate using patterned hydrophobic/hydrophilic regions. Liquid lenses were formed by...

The authors report on the development of surfaces containing artificially fabricated structures of dual nanometer and micrometer surfaces that allow an aqueous droplet to be reversibly switched by electrowetting from a Cassie state with low adhesion to a Wenzel state with high adhesion. A variety of geometries were fabricated to...

The ability to reversibly switch between a hydrophobic Cassie state and a hydrophilic Wenzel state is often not possible on textured surfaces because of energy barriers which result from the geometry of the microstructure. In this paper, we report on a simple microstructure geometry that allows an aqueous droplet to...

This paper reports on the design, fabrication, and performance of micro-sized fluidic devices that use electrowetting to control and transport liquids. Using standard microfabrication techniques, new pumping systems are developed with significantly more capability than open digital microfluidic systems that are often associated with electrowetting. This paper demonstrates that, by...

Applications of microfluidics require a self-contained, active pumping system in which the package size is comparable to the volume of fluid being transported. Over the past decade, several systems have been developed to address this issue, but either these systems have high power requirements or the microfabrication is too complex...

A study was conducted to investigate electrowetting reversibility associated with repeated voltage actuations for an aqueous droplet situated on a silicon dioxide insulator coated with an amorphous fluoropolymer film ranging in thickness from 20 to 80 nm. The experimental results indicate that irreversible trapped charge may occur at the aqueous-solid...

Methods for accurately characterizing aerosols are required for detecting biological warfare agents. Currently, fluorescence-based biological agent sensors provide adequate detection sensitivity but suffer from high false-alarm rates. Combining single-particle fluorescence analysis with laser-induced breakdown spectroscopy (LIBS) provides additional discrimination and potentially reduces false-alarm rates. A transportable UV laser-induced fluorescence-cued LIBS...

This paper investigates the nonideal electrowetting behavior of thin fluoroploymer films. Results are presented for a three phase system consisting of: (1) an aqueous water droplet containing sodium dodecyl sulfate (SDS), (2) phosphorous-doped silicon topped with SiO2 and an amorphous fluoroploymer (aFP) insulating top layer on which the droplet is...

This study presents methods for engineering the electrocapillary behavior of fluoropolymer surfaces through the use of surfactants and an external insulating liquid. By the scaling of the appropriate surface energies, electrocapillary behavior is obtained at a record low voltage, with contact angle changes in excess of 100[degrees] at 4 V...