Milling Positive Master for Polydimethylsiloxane Microfluidic Devices: The Microfabrication and Roughness Issues

Area of Science:

• Materials Science
• Microfluidics
• Manufacturing Engineering

Background:

• Microfluidic devices are crucial for various applications.
• Fabricating microchannels in polydimethylsiloxane (PDMS) often involves complex or costly methods.
• Existing techniques can face challenges with narrow channel fabrication and tool durability.

Purpose of the Study:

• To present a facile and low-cost method for fabricating PDMS-based microchannels.
• To demonstrate the utility of a milling technique for creating microscale masters.
• To address limitations in fabricating narrow microchannels and surface roughness.

Main Methods:

• Fabrication of a positive microscale master on an acrylic block using milling.
• Molding of the master with pre-cured PDMS to create the microchannel structure.
• Peeling, puncturing, and O₂ plasma bonding of the PDMS plate to a glass slide.

Main Results:

• Successful fabrication of PDMS microchannels using a simple, quick, and inexpensive protocol.
• Avoidance of end mill breakage during the fabrication of channels narrower than 50 µm.
• Mitigation of surface roughness issues through the use of pre-cured PDMS and design adjustments.

Conclusions:

• The proposed milling technique offers an efficient and cost-effective approach for PDMS microchannel fabrication.
• This method is suitable for producing narrow microchannels without damaging milling equipment.
• The successful demonstration of emulsion formation validates the proposed microfabrication protocol.