Surfactant-Stabilized Virtual Microchannels between Electrowetting-Driven Droplets
Date Issued
2015
Date
2015
Author(s)
Lu, Hsin-Yi
Abstract
In recent years, constructing flow channels on a micro scale has been intensively investigated. In order to improve the flexibility of the microchannels by removing their physical sidewalls, we demonstrate reprogrammable virtual microchannels on a digital microfluidic platform using electrowetting-on-dielectric (EWOD). We added different kinds of surfactants, Pluronic F127, Pluronic F68, TWEEN 20, and Triton X-100 to distilled deionized (DD) water at their critical micelle concentration (CMC). The virtual microchannels were established between two parallel Indium Tin Oxide (ITO) coated glass plates. A reprogrammable virtual microchannel without physical sidewalls between two droplets was achieved and stabilized simply due to the surfactant molecules. By using different patterns of the electrodes, we created virtual microchannels in various forms, lengths (from 1000 um to 5000 um), and heights (from 20 um to 180 um). We obtained high aspect ratios as 60 when the virtual microchannel was 100 um high and 1.74 um wide. We applied different voltages on the two sides of the microchannel to generate uneven pressure and to pump the liquid. Furthermore, we put 1 um particles into the liquid for visualizing the flow. Individual particles passing through the microchannel at a time were observed. The pumping rate was about 0.0088 nL/s to 0.0382 nL/s. Moreover, DNA molecules were stretched with the flow in the virtual microchannels.
Subjects
Virtual microchannel
electrowetting
pumping
surfactant
DNA stretching
Type
thesis
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