Microfluidic ratio metering devices fabricated in PMMA by CO2 laser
1NIBEC, Ulster University, Belfast, BT37 0QB Northern Ireland, UK.
Microsystem Technologies : Sensors, Actuators, Systems Integration
|February 8, 2021
Summary
This study details microfluidic fabrication using CO2 lasers on PMMA, creating U-shaped and V-shaped channels. These microfluidic devices are suitable for ocean sensing and biomedical applications.
Area of Science:
- Materials Science and Engineering
- Microfluidics and Lab-on-a-Chip Technology
- Laser-Based Manufacturing
Background:
- Microfluidic devices are crucial for various sensing applications, including environmental and biomedical fields.
- Efficient and precise fabrication methods are essential for developing advanced microfluidic systems.
- Polymethyl methacrylate (PMMA) is a common material for microfluidic device fabrication due to its optical clarity and machinability.
Purpose of the Study:
- To investigate and characterize microfluidic channel fabrication on cast PMMA using a 10.6 μm CO2 engraving laser.
- To compare the effects of raster and vector laser writing modes on channel geometry and surface properties.
- To explore post-fabrication treatments for channel smoothing and transparency enhancement.
Main Methods:
- Microfluidic channels were fabricated on cast PMMA using a CO2 laser in both raster and vector modes.
- Different focusing optics, including a 1.5″ lens and a High Power Density Focussing Optics lens, were employed.
- Channel cross-sections were analyzed using imaging and stylus profilometry. Post-fabrication treatments included heated IPA etching and chloroform vapor treatment.
Main Results:
- Raster laser writing produced U-shaped channels with a flatter base, while vector writing resulted in V-shaped channels.
- Channel steepness in vector mode increased with laser power; laser defocus allowed for broader, shallower channels.
- Heated IPA etching smoothed raster-engraved channels, and chloroform vapor treatment enhanced transparency. Bonding was achieved via chloroform vapor treatment.
Conclusions:
- CO2 laser engraving offers a versatile method for fabricating microfluidic devices in PMMA with controllable channel geometries.
- Post-fabrication treatments can significantly improve channel surface finish and optical properties.
- The fabricated microfluidic devices are suitable for applications such as dissolved CO2 analysis in ocean sensing and broader biomedical sensing platforms.
