Coaxial flow focusing in poly(dimethylsiloxane) microfluidic devices.

Area of Science:

• Microfluidics
• Materials Science
• Chemical Engineering

Background:

• Coaxial flow focusing is a key technique for producing emulsions.
• Existing methods using glass capillaries have limitations in scalability and integration.
• Poly(dimethylsiloxane) (PDMS) is a versatile material for microfluidic device fabrication.

Purpose of the Study:

• To develop a novel coaxial flow focusing geometry using soft lithography in PDMS.
• To enable scalable and clog-resistant formation of small double emulsions.
• To integrate the geometry into parallel drop-maker arrays.

Main Methods:

• Fabrication of coaxial flow focusing geometry using soft lithography in PDMS.
• Characterization of double emulsion formation and size control.
• Evaluation of device robustness against fouling and clogging.

Main Results:

• The PDMS geometry successfully formed double emulsions with sizes smaller than channel dimensions.
• Emulsions down to 7 micrometers in diameter were produced scalably.
• The microfluidic channels demonstrated robustness against fouling and clogging.

Conclusions:

• Soft lithography in PDMS provides a scalable method for fabricating coaxial flow focusing devices.
• This technology enables the production of small, uniform double emulsions in clog-resistant, large channels.
• The developed geometry is suitable for integration into parallel drop-maker arrays for high-throughput applications.