In fields such as microfluidics, liquid chromatography, IVD instruments, and drug development, the choice of materials for fluidic components directly impacts equipment accuracy, service life, and system stability.
In the past, metallic materials such as 316L stainless steel and titanium alloys were widely used in precision fluidic components. However, in applications involving micron-scale channels, high-purity media, corrosive reagents, and biological testing, metallic materials may face issues such as burrs, corrosion, metal ion leaching, and sample adsorption.
Consequently, engineering plastics such as PEEK, PTFE, PFA, and PEI are increasingly becoming the preferred materials of choice for microfluidic components.
What are the advantages of engineering plastics in the microfluidics industry?
I. Why Not Metal? The “Four Challenges” of Microfluidic Channels
PEEK Valve Bodies vs. Metal Valve Bodies
The channel dimensions in microfluidic systems are typically very small, meaning even minor surface defects in the material are magnified. For fluidic components, the material must not only be “functional” but also remain stable over the long term.
01
Burrs and Cleanliness:
Micro-pores and cross-holes are prone to trapping burrs, which can affect flow stability and system cleanliness.
02
Chemical Corrosion and Metal Ion Leaching:
In environments with high salt concentrations, strong acids or bases, or organic solvents, metals may corrode and contaminate the sample.
03
Applications such as biocompatible
IVD and life sciences require low adsorption, sterilizability, and stable contact.
04
Complex structures and the need for lightweight design
—micro-holes, narrow slots, and thin-walled structures—place greater demands on manufacturing and assembly efficiency.
II. Analysis of the Properties of Four Major Engineering Plastics
Microfluidic systems feature extremely small channel dimensions, and factors such as material surfaces, channel junctions, and machining residues can all affect fluid stability.
PEEK
High-temperature resistance | High strength | Pressure resistance. Suitable for high-pressure valve bodies, pump heads, chromatography fittings, and microfluidic precision components.
PTFE
Corrosion-resistant | Low friction | Non-stick | Low adsorption: Suitable for low-pressure piping, gaskets, diaphragms, and corrosion-resistant linings
PFA
Corrosion-resistant | High-purity | Translucent | Dimensionally stable Suitable for high-purity chemical piping, semiconductor flow paths, and bioanalytical instruments
PEI
Heat-resistant | High rigidity | Injection-moldable | Cost-effective Suitable for fixtures, substrates, enclosures, and chip sockets
III. Key Considerations for Selecting Three Types of Core Components
Valves, pump heads, and tubing connectors are the three types of components most likely to affect the stability of microfluidic systems. When selecting these components, attention must be paid to internal burrs, corrosion resistance, dimensional stability, low leaching, and low adsorption.
IV. Quick Selection Guide
| Material | Temperature Resistance | Chemical Resistance | Mechanical Strength | Transparency | Cost |
| PEEK | High 260℃ | Excellent Resistant to most organic solvents | Extremely high | Opaque | High |
| PTFE | High 260℃ | Virtually corrosion-resistant | Relatively low | Opaque | Medium |
| PFA | High 260℃ | Virtually corrosion-resistant | Moderate | Translucent | High |
| PEI | Medium-High 180 ℃ | Moderate | High | Amber-colored and translucent | Medium |
V. More Than Just Materials—It’s About Craftsmanship
01 Process Design
02 Precision Machining
03 Deburring and Cleaning
04 Inspection and Validation
High-precision components require special attention to: structural process evaluation, precision machining parameters, internal flow channel deburring, cleaning, and microscopic inspection.
Poor machining: Visible burrs and residue at the hole opening
Good machining: Cleaner hole opening and more consistent contour
IV. Conclusion
In microfluidic applications, there is no single “best” material; rather, there are materials that are better suited to specific operating conditions. PEEK excels in overall performance, PTFE/PFA in corrosion resistance and high purity, and PEI in structural integrity and cost-effectiveness. Selecting the right material must be paired with appropriate processing techniques to ensure long-term, stable system operation.