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Download fileElectric Scissors for Precise Generation of Organic Droplets in Microfluidics: A Universal Approach that Goes beyond Surface Wettability
journal contribution
posted on 2019-10-15, 12:09 authored by Shuai Yin, Yi Huang, Teck Neng Wong, Wen Han Chong, Kim Tiow OoiMultifarious
organic phase droplets have emerged in diverse applications
such as material synthesis and biological pharmacy; accordingly, the
organic droplet generation demands more on the usability and the controllability.
In this article, we demonstrate a universal and simple method to actively
generate organic in water (O/W) droplet in a poly(dimethylsiloxane)
(PDMS)-based microfluidics device by using both DC and AC electric
fields to cut a stable layered flow of the disperse phase into dispersed
droplets or liquid slugs in a precise manner. The system demonstrates
the feature of ultrafast response and precise control of O/W droplet
generation. The biggest advantage of the proposed approach is that
it removes the necessity for surface treatment in conventional O/W
droplet formation in PDMS microchannels, breaking the limits brought
by the surface wettability for the first time and rendering itself
to be a universal method for O/W droplet generation. We also explored
the breakup of the disperse phase, catalogued them into three stages
with sinusoidal AC electric fields, namely, nonbreakup, transition,
and continuous breakup and mapped the voltage boundaries in these
stages. To demonstrate their general application to generate organic
droplets, we executed these control strategies on four typical organic
fluids, each flowing with different hydrodynamic characteristics.
The results showed precise cutting and tuning effects from the square
and the sinusoidal wave electric fields. Our findings propose a potentially
universal active formation technique for the organic-based solutions
droplet and widen the applications of the microfluidics.
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Keywords
material synthesisapplicationOrganic Dropletssurface treatmentorganic-based solutions dropletformation techniqueUniversal ApproachPDMS microchannelscontrol strategiessurface wettabilityphase dropletsdroplet generation demandsultrafast responseSurface Wettability Multifarioushydrodynamic characteristicsElectric ScissorsDCACvoltage boundariesPrecise Generation