Thermoplastic microchannel fabrication using carbon dioxide laser ablation

Area of Science:

• Materials Science
• Microfluidics
• Analytical Chemistry

Background:

• Microfluidic devices are crucial for various analytical applications.
• Fabricating microchannels on thermoplastic substrates offers cost-effectiveness and scalability.
• Existing methods for microchannel fabrication can be complex or expensive.

Purpose of the Study:

• To develop a simple and efficient method for machining microchannels on Vivak co-polyester thermoplastic substrates.
• To investigate the surface properties and fluid dynamics within laser-ablated microchannels.
• To assess the suitability of these microchannels for particle analysis using electrophoresis.

Main Methods:

• Utilizing a CO2 laser marker with low-power settings in a nearly anaerobic environment to machine microchannels.
• Applying alkaline hydrolysis treatment to ablate channel surfaces for charge induction.
• Conducting electroosmotic flow (EOF) measurements and dynamic coating protocols.
• Employing video microscopy to analyze particle electrophoretic mobility.

Main Results:

• Successfully machined microchannels with various aspect ratios and designs (straight, serpent) on thermoplastic substrates.
• Ablated channel surfaces acquired a charge after alkaline hydrolysis, enabling stable electroosmotic flow.
• EOF in the ablated channels was comparable in magnitude to that in fused silica capillaries.
• Surface modification and buffer acidity effects on EOF were similar to fused silica.
• Demonstrated utility in distinguishing electrophoretic mobilities of different particle types.

Conclusions:

• Low-power CO2 laser machining is a viable technique for fabricating functional microchannels on thermoplastic substrates.
• The laser-ablated microchannels exhibit properties suitable for microfluidic applications, including stable EOF.
• These cost-effective microfluidic devices can be utilized for sensitive particle analysis and separation.