Marangoni stress-driven droplet manipulation on smart polymers for ultra-low voltage digital microfluidics

a smart polymer and stress-driven technology, applied in the field of digital microfluidic systems for the manipulation of liquid droplets, can solve the problems of oxidizing smart polymers, surface hydrophilicity, and loss of positive charges

a smart polymer and stress-driven technology, applied in the field of digital microfluidic systems for the manipulation of liquid droplets, can solve the problems of oxidizing smart polymers, surface hydrophilicity, and loss of positive charges

US20120248229A1Inactive Publication Date: 2012-10-04STEVENS INSTITUTE OF TECHNOLOGY
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  • Marangoni stress-driven droplet manipulation on smart polymers for ultra-low voltage digital microfluidics
  • Marangoni stress-driven droplet manipulation on smart polymers for ultra-low voltage digital microfluidics
  • Marangoni stress-driven droplet manipulation on smart polymers for ultra-low voltage digital microfluidics

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[0023]The Marangoni effect is the mass transfer along an interface between two fluids (e.g., an electrolytic bath and a droplet of immiscible liquid within the bath) due to a surface tension gradient. Since a liquid with high surface tension pulls more strongly on the surrounding liquid than one with a low surface tension, the presence of a gradient in surface tension causes the liquid to move away from a region of low surface tension to a region of high surface tension. The induced force at the liquid-liquid interface is the so-called Marangoni stress.

[0024]The present invention provides a microfluidic system that enables the operation of microfluidic devices at low voltages, such as those which can be provided by commercial-standard 1.5 V batteries, using the Marangoni effect to induce Marangoni stress between adjacent electrodes comprising a smart polymer. Certain embodiments of the present invention can be substituted for those employing the existing electrowetting-on-dielectric...

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Abstract

An ultra-low voltage microfluidic device for manipulating droplets of liquid by inducing Marangoni stress therein includes a plurality of smart-polymer electrodes having films of smart polymer exposed at their surfaces. The surface of the smart polymer becomes hydrophobic or hydrophilic in response to different electromagnetic potentials. The smart polymer is reversibly oxidized by applying an electrical potential such that the smart polymer acquires a positive electrical charge. The oxidized smart polymer is reduced by applying an electrical potential such that it loses its positive electrical charge. The smart polymer is doped with a chemical compound having a negatively-charged end and a long-chain hydrophobic tail. The smart polymer is a polypyrrole and the dopant is a dodecylbenzene sulfonate. The microfluidic device includes a plurality of individually-addressable control electrodes, each of which is electrically-connected with smart-polymer electrodes. Droplets are transported, cut, or mixed by selectively applying electrical potential to individual electrodes.

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Application Information

Patent Timeline
04 Oct 2012
Publication
US20120248229A1