Negative Pressure Induced Droplet Generation in a Microfluidic Flow-Focusing Device.

We introduce an effective method to actively induce droplet generation using negative pressure. Droplets can be generated on demand using a series of periodic negative pressure pulses. Fluidic network models were developed using the analogy to electric networks to relate the pressure conditions for different flow regimes. Experimental results show that the droplet volume is correlated to the pressure ratio with a power law of 1.3. Using a pulsed negative pressure at the outlet, we are able to produce droplets in demand and with a volume proportional to the pulse width.

[1]  I. Kevrekidis,et al.  Droplet and slug formation in polymer electrolyte membrane fuel cell flow channels: The role of inte , 2011 .

[2]  H. Bruce Stewart,et al.  Two-phase flow: Models and methods , 1984 .

[3]  Charles M Schroeder,et al.  A microfluidic-based hydrodynamic trap: design and implementation. , 2011, Lab on a chip.

[4]  S. M. Sohel Murshed,et al.  Thermally controlled droplet formation in flow focusing geometry: formation regimes and effect of nanoparticle suspension , 2008 .

[5]  Bifeng Liu,et al.  Encapsulation of single cells on a microfluidic device integrating droplet generation with fluorescence-activated droplet sorting , 2013, Biomedical Microdevices.

[6]  G. Whitesides,et al.  Mechanism for flow-rate controlled breakup in confined geometries: a route to monodisperse emulsions. , 2005, Physical review letters.

[7]  Stephan Herminghaus,et al.  Optimized droplet-based microfluidics scheme for sol-gel reactions. , 2010, Lab on a chip.

[8]  D. Weitz,et al.  Fluorescence-activated droplet sorting (FADS): efficient microfluidic cell sorting based on enzymatic activity. , 2009, Lab on a chip.

[9]  Nam-Trung Nguyen,et al.  Oxygen plasma treatment for reducing hydrophobicity of a sealed polydimethylsiloxane microchannel. , 2010, Biomicrofluidics.

[10]  Nam-Trung Nguyen,et al.  Self-Aligned Interdigitated Transducers for Acoustofluidics , 2016, Micromachines.

[11]  A. Abate,et al.  High-throughput injection with microfluidics using picoinjectors , 2010, Proceedings of the National Academy of Sciences.

[12]  S. Fan,et al.  Encapsulated droplets with metered and removable oil shells by electrowetting and dielectrophoresis. , 2011, Lab on a chip.

[13]  R. Zengerle,et al.  Centrifugal generation and manipulation of droplet emulsions , 2006 .

[14]  George M. Whitesides,et al.  Formation of monodisperse bubbles in a microfluidic flow-focusing device , 2004 .

[15]  M. Kreutzer,et al.  Monodisperse hydrogel microspheres by forced droplet formation in aqueous two-phase systems. , 2011, Lab on a chip.

[16]  Kan Liu,et al.  Microfluidic device for robust generation of two-component liquid-in-air slugs with individually controlled composition , 2010, Microfluidics and nanofluidics.

[17]  Nam-Trung Nguyen,et al.  Acoustofluidic control of bubble size in microfluidic flow-focusing configuration. , 2015, Lab on a chip.

[18]  Magalie Faivre,et al.  Microfluidic flow focusing: Drop size and scaling in pressure versus flow‐rate‐driven pumping , 2005, Electrophoresis.

[19]  Wei Guo,et al.  AC electric field induced droplet deformation in a microfluidic T-junction. , 2016, Lab on a chip.

[20]  S Elizabeth Hulme,et al.  Incorporation of prefabricated screw, pneumatic, and solenoid valves into microfluidic devices. , 2009, Lab on a chip.

[21]  Zhuang Jie Chong,et al.  Automated droplet measurement (ADM): an enhanced video processing software for rapid droplet measurements , 2016, Microfluidics and Nanofluidics.

[22]  S. Tan,et al.  Generation and manipulation of monodispersed ferrofluid emulsions: the effect of a uniform magnetic field in flow-focusing and T-junction configurations. , 2011, Physical review. E, Statistical, nonlinear, and soft matter physics.

[23]  Abraham P Lee,et al.  A Laplace pressure based microfluidic trap for passive droplet trapping and controlled release. , 2012, Biomicrofluidics.

[24]  Yangcheng Lu,et al.  Direct measurement of the differential pressure during drop formation in a co-flow microfluidic device. , 2014, Lab on a chip.

[25]  J. Baret,et al.  Microfluidic flow-focusing in ac electric fields. , 2014, Lab on a chip.

[26]  X. Y. Ye,et al.  A novel thermally-actuated silicon micropump , 1997, 1997 International Symposium on Micromechanics and Human Science (Cat. No.97TH8311).