Related Experiment Video
Updated: Mar 12, 2026
10:22
High Speed Droplet-based Delivery System for Passive Pumping in Microfluidic Devices
Published on: September 2, 2009
14.3K
Passive and active droplet generation with microfluidics: a review
1Department of Mechanical Engineering, The University of Hong Kong, Hong Kong, China. lqwang@hku.hk and HKU-Zhejiang Institute of Research and Innovation (HKU-ZIRI), 311300, Hangzhou, Zhejiang, China.
Lab on a Chip
|November 15, 2016
Summary
Understanding droplet generation is key for microfluidics. This review unifies passive and active methods, aiding new technique development for materials synthesis and lab-on-a-chip systems.
Area of Science:
- Microfluidics
- Materials Science
- Chemical Engineering
Background:
- Precise droplet generation is crucial for microfluidic applications, including materials synthesis and lab-on-a-chip systems.
- Existing methods are categorized as passive (no external actuation) or active (requiring energy input).
- A unified physical understanding of both approaches is needed for developing advanced droplet generation techniques.
Approach:
- This review analyzes passive droplet generation methods, detailing breakup modes in microfluidic configurations like cross-flow, co-flow, flow-focusing, and step emulsification.
- Active methods are reviewed, covering techniques using external fields (electrical, magnetic, centrifugal) and intrinsic fluid property modifications (velocity, viscosity, interfacial tension, wettability, density).
- The review focuses on the implementation and actuation mechanisms of various active droplet generation strategies.
Key Points:
- Passive methods rely on inherent flow dynamics and microchannel geometries for droplet formation.
- Active methods leverage external forces or altered fluid properties to induce droplet breakup.
- A comparative analysis of passive and active approaches highlights their respective advantages and limitations.
Conclusions:
- A comprehensive understanding of both passive and active droplet generation mechanisms is essential for optimizing microfluidic device performance.
- This review provides a unified perspective, facilitating the design of novel droplet generation techniques tailored to specific application requirements.
- Further research into integrating and optimizing these methods will drive innovation in microfluidics and related fields.
