Passive and active droplet generation with microfluidics: a review
Precise and effective control of droplet generation is critical for applications of droplet microfluidics ranging from materials synthesis to lab-on-a-chip systems. Methods for droplet generation can be either passive or active, where the former generates droplets without external actuation, and the...
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| Published in | Lab on a chip Vol. 17; no. 1; pp. 34 - 75 |
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| Main Authors | , |
| Format | Journal Article |
| Language | English |
| Published |
England
20.12.2016
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| Subjects | |
| Online Access | Get full text |
| ISSN | 1473-0197 1473-0189 |
| DOI | 10.1039/c6lc01018k |
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| Summary: | Precise and effective control of droplet generation is critical for applications of droplet microfluidics ranging from materials synthesis to lab-on-a-chip systems. Methods for droplet generation can be either passive or active, where the former generates droplets without external actuation, and the latter makes use of additional energy input in promoting interfacial instabilities for droplet generation. A unified physical understanding of both passive and active droplet generation is beneficial for effectively developing new techniques meeting various demands arising from applications. Our review of passive approaches focuses on the characteristics and mechanisms of breakup modes of droplet generation occurring in microfluidic cross-flow, co-flow, flow-focusing, and step emulsification configurations. The review of active approaches covers the state-of-the-art techniques employing either external forces from electrical, magnetic and centrifugal fields or methods of modifying intrinsic properties of flows or fluids such as velocity, viscosity, interfacial tension, channel wettability, and fluid density, with a focus on their implementations and actuation mechanisms. Also included in this review is the contrast among different approaches of either passive or active nature.
We present a comprehensive review on the fundamentals of passive and active microfluidic droplet generation. |
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| Bibliography: | Prof. L. Q. Wang received his PhD from University of Alberta in 1995 and is currently a professor in the Department of Mechanical Engineering, the University of Hong Kong. He is also a Qianren Scholar (Zhejiang) and serves as the director and the chief scientist for the Laboratory for Nanofluids and Thermal Engineering, Zhejiang Institute of Research and Innovation, the University of Hong Kong. Prof. Wang has over 20 years of university experience in thermal and power engineering, energy and environment, transport phenomena, nanotechnology, biotechnology and applied mathematics in Canada, China/Hong Kong, Singapore and the USA, and has led a team in developing a state-of-the-art thermal control system for the Alpha Magnetic Spectrometer (AMS) on the International Space Station. Prof. Wang's current research is mainly on microfluidic bubbles/droplets/particles, soft materials, flow bifurcation and stability, heat transfer with thermal waves and resonance, numerical simulation and nonlinear computation. Pingan Zhu received his bachelor's degree in Safety Science and Engineering from the University of Science and Technology of China in 2013. He is currently a PhD candidate in the department of Mechanical Engineering, the University of Hong Kong. His research interest is in microfluidic droplet generation and droplet-templated materials synthesis. ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-3 content type line 23 ObjectType-Review-1 ObjectType-Article-1 ObjectType-Feature-2 |
| ISSN: | 1473-0197 1473-0189 |
| DOI: | 10.1039/c6lc01018k |