Thermoplastics vs Glass and Silicon in Microfluidics

Microfluidic devices are increasingly used in diagnostics, life science research, and point-of-care applications. As concepts move closer to real-world deployment, engineers face a key decision: which material allows a smooth transition from prototype to scalable production?

For decades, glass and silicon were the standard substrates thanks to their optical and structural properties. However, they present manufacturing limitations that slow down development and increase cost.

Modern thermoplastics, especially COC/COP, PS and PMMA, offer a practical alternative. They provide high optical clarity, biocompatibility, and compatibility with mass-production processes such as injection molding. This makes them a strong option for teams aiming to scale efficiently.

Key Advantages of Thermoplastics for Microfluidic Chips

Thermoplastics provide several advantages for microfluidic chip fabrication:

• Scalable manufacturing through injection molding

• Lower per-unit cost after tooling is established

• CNC-friendly for early prototyping and design verification

• High optical transparency, suitable for imaging and fluorescence detection

• Multiple bonding options (thermal, solvent, ultrasonic, laser)

  
  

These materials allow engineers to move from first design to production more predictably. As a result, thermoplastics are widely adopted in modern microfluidic workflows.

Learn more about materials used in microfluidic manufacturing >>>.

Comparison of Glass, Silicon, and Thermoplastics in Microfluidics

Property	Glass	Silicon	Thermoplastics (COC/COP/PS/PMMA)
Fabrication method	Wet/dry etching	Photolithography	Injection molding, CNC machining
Setup cost	High	Very high	Moderate
Lead time	Long	Long	Short
Minimum feature size	~10–20 µm	~1–5 µm	~5–10 µm
Optical clarity	Excellent	Low	Excellent (COC, PMMA)
Chemical resistance	Very high	High	Moderate to high (material-dependent)
Bonding complexity	High (anodic, fusion)	High (plasma)	Low to moderate
Scalability	Limited	Limited	High
Design iteration speed	Slow	Very slow	Fast

Source: ResearchGate, 2024; Micromolds internal analysis; Microfluidics Innovation Center

Why Glass Is Being Replaced

Glass microfluidic chips offer excellent chemical inertness, optical transparency, and pressure resistance. However, several factors limit its scalability:

• Multi-step etching processes

• High-temperature or anodic bonding

• Brittle handling properties

• Long manufacturing lead times

• Limited flexibility for design changes

  
  

Glass is suitable for specialized research devices but often impractical for commercial production.

Why Silicon Has Lost Ground

Silicon has long been used in MEMS manufacturing. In microfluidics, however, it presents challenges:

• Opaque surface restricts optical detection

• Requires cleanroom facilities

• High cost per unit

• Fragile, prone to chipping

• Limited scalability due to mask-based processing

  
  

Silicon is now mostly used for integrated sensor applications rather than fluidic structures.

Why Thermoplastics Fit Modern Manufacturing Needs

Thermoplastics address the challenges seen with glass and silicon:

• Support high-volume injection molding

• Enable rapid prototyping through CNC machining

• Provide consistent replication of micro-features

• Reduce manufacturing cost at scale

• Offer multiple bonding options to suit different designs

  
  

For many diagnostics and life science applications, thermoplastics strike an effective balance between performance, cost, and manufacturability.

Explore more about microfluidic fabrication>>>.

Frequently Asked Questions

Is COC better than glass for diagnostics?

For most diagnostic applications, COC offers comparable optical clarity with much faster, scalable, and cost-effective manufacturing.

Can thermoplastics achieve similar feature sizes to silicon?

While silicon can reach smaller features, thermoplastics offer sufficient resolution (~5µm) for most microfluidic channels.

Are thermoplastic chips reliable for clinical use?

Yes. Thermoplastics like COC/COP, PS and PMMA are biocompatible, stable, and already used in regulatory-cleared devices.

Does Micromolds support both prototyping and mass production?

Yes. We provide CNC prototyping and full-scale injection molding under one roof.

Request a Microfluidic Manufacturing Consultation

If you are transitioning from glass or silicon to thermoplastic microfluidic designs, our engineering team can review your requirements and propose a suitable manufacturing approach.

Contact Micromolds >>> to begin your review.