Concentric Capillary Microfluidic Devices Designed for Robust Production of Multiple-Emulsion Droplets

Area of Science:

• Microfluidics
• Materials Science
• Chemical Engineering

Background:

• Multiple emulsions serve as templates for microcapsule fabrication due to their core-shell structure.
• Existing glass capillary devices face clogging and stability issues with partially miscible fluids.

Purpose of the Study:

• To develop novel capillary microfluidic devices for optimized multiple emulsion droplet production.
• To address and mitigate precipitation and clogging problems encountered with partially miscible fluids.

Main Methods:

• Design and fabrication of capillary microfluidic devices with two or three concentric capillary channels.
• Utilizing rotational adjustments of tapered capillaries for precise coaxial fluid injection.
• Simultaneous coaxial injection of fluids to minimize pre-emulsification contact.

Main Results:

• Consistent production of highly uniform double, triple, and quadruple emulsion droplets.
• Precise control over droplet diameters and layer thicknesses achieved.
• Broadened range of usable fluid combinations due to reduced pre-emulsification fluid contact.

Conclusions:

• The novel concentric capillary devices effectively overcome clogging and stability issues.
• These devices enable reliable production of complex multiple emulsions.
• Opens new avenues for microcapsule development in pharmaceuticals and cosmetics.