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A solvent-free initiated chemical vapor deposition (iCVD) process was used to create low surface energy poly(1H,1H,2H,2H-perfluorodecyl acrylate) (PPFDA) thin films at deposition rates as high as 375 nm/min. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy showed full retention of the fluorine moieties, and no measurable(More)
This paper describes an analytical system that uses magnetic levitation to measure densities of solids and water-immiscible organic liquids with accuracies ranging from +/-0.0002 to +/-0.02 g/cm(3), depending on the type of experiment. The technique is compatible with densities of 0.8-3 g/cm(3) and is applicable to samples with volumes of 1 pL to 1 mL; the(More)
This article describes FLASH (Fast Lithographic Activation of Sheets), a rapid method for laboratory prototyping of microfluidic devices in paper. Paper-based microfluidic devices are emerging as a new technology for applications in diagnostics for the developing world, where low cost and simplicity are essential. FLASH is based on photolithography, but(More)
This paper demonstrates that a hand-powered egg beater can be modified to serve as a centrifuge for separating plasma from human whole blood. Immunoassays used to diagnose infectious diseases often require plasma from whole blood, and obtaining plasma typically requires electrically-powered centrifuges, which are not widely available in resource-limited(More)
Droplet-based microfluidic platforms have the potential to provide superior control over mixing as compared to traditional batch reactions. Ionic liquids have advantageous properties for metal nanoparticle synthesis as a result of their low interfacial tension and complexing ability; however, droplet formation of ionic liquids within microfluidic channels(More)
The use of delivery templates makes it possible to fabricate shaped, millimeter-thick heterogeneously patterned films of ionotropic hydrogels. These structures include two-dimensional (2-D) patterns of a polymer cross-linked by different ions (e.g., alginic acid cross-linked with Ca2+ and Fe3+) and patterns of step gradients in the concentration of a single(More)
This article describes the use of paper—patterned either by hand or with a color laser printer—to fabricate films of ionotropic hydrogels structured into regular shapes with lateral dimensions from 2 mm to several centimeters, and with thicknesses from 0.2 to 1.3 mm. Water-soluble polymers such as alginic acid (AA) and carboxymethyl cellulose (CMC) form(More)
We have demonstrated the application of low surface energy fluoropolymer coatings onto poly(dimethylsiloxane) (PDMS) microfluidic devices for droplet formation and extraction-induced merger of droplets. Initiated chemical vapor deposition (iCVD) was used to pattern fluoropolymer coatings within microchannels based on geometrical constraints. In a two-phase(More)
Paper-based microfluidic devices have recently received significant attention as a potential platform for low-cost diagnostic assays. However, the number of advanced unit operations, such as separation of analytes and fluid manipulation, that can be applied to these devices has been limited. Here, we use a vapor phase polymerization process to sequentially(More)