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On-chip droplet production regimes using surface acoustic waves
Jason C Brenker1, David J Collins1, Hoang Van Phan1
1Laboratory for Micro Systems, Department of Mechanical and Aerospace Engineering, Monash University, Clayton, Victoria 3800, Australia. adrian.neild@monash.edu.
Lab on a Chip
|April 6, 2016
Summary
We developed an on-demand method for producing femtolitre droplets using surface acoustic waves (SAW). This technique enables precise control over droplet size and quantity for microfluidic applications.
Area of Science:
- Microfluidics
- Acoustofluidics
- Chemical Analysis
Background:
- Microfluidic devices utilize aqueous droplets in immiscible fluids for chemical analysis.
- Current droplet production methods include batch, continuous, and on-demand emulsification.
- On-demand production offers superior control over droplet size and quantity, crucial for specific applications.
Purpose of the Study:
- To present a novel method for on-demand production of femtolitre droplets.
- To investigate the impact of surface acoustic waves (SAW) on droplet generation.
- To explore droplet formation across various flow rates and physical regimes.
Main Methods:
- Utilized high-frequency surface acoustic waves (SAW) to generate pressure for droplet production.
- Incorporated a quasi-3D feature at the nozzle to increase continuous phase flow rate.
- Investigated droplet formation across a range of flow rates.
Main Results:
- Achieved on-demand production of femtolitre droplets as small as 200 fL.
- Demonstrated droplet sizes approximately 1/60th of previously reported minimum volumes.
- A numerical model confirmed the relationship between pulse length and droplet formation.
Conclusions:
- The SAW-driven method provides precise on-demand control over femtolitre droplet generation.
- This technique expands the capabilities of microfluidic chemical analysis platforms.
- The findings pave the way for more sophisticated microfluidic applications requiring small, controlled sample volumes.
