Fabrication of Conical Microstructure Array for Stable Droplet Generation Over Wide Flow Rate Range

Area of Science:

• Microfluidics
• Materials Science
• Chemical Engineering

Background:

• Droplet generators are crucial for microfluidic analysis systems.
• Flow fluctuations often lead to polydisperse droplets, hindering precise analysis.
• Achieving stable, desired-size droplet generation remains a significant challenge.

Purpose of the Study:

• To develop a high-performance droplet generator resistant to flow fluctuations.
• To investigate the mechanism of a functional conical array in droplet generation.
• To enable the production of monodisperse droplets over a wide flow range.

Main Methods:

• Fabrication of conical microstructures via selective etching of a silicon nitride/silicon substrate using potassium hydroxide (KOH).
• Integration of the conical array into the junction of microfluidic channels.
• Characterization of droplet generation performance under varying flow conditions.

Main Results:

• The conical microstructures effectively regulate the continuous phase flow rate.
• This regulation facilitates the transition to the necking phase, promoting easier droplet shedding.
• The developed droplet generator produces monodisperse droplets across a broad range of flow rates.

Conclusions:

• A novel droplet generator design utilizing a functional conical array significantly improves droplet size uniformity.
• The conical microstructures play a key role in stabilizing droplet formation by managing continuous phase flow.
• This research offers valuable insights for designing high-quality droplet generation devices for microfluidics.