Selecting the wrong tubing material for a chemical process, semiconductor tool, or medical device can cause contamination, failure, or safety incidents. PTFE, PEEK, and PFA are three of the most commonly specified high-performance plastic tubing materials — and all three are sold by vendors who will tell you theirs is the right choice.
This guide cuts through that. We manufacture PTFE and PFA tubing and supply across semiconductor, medical, and chemical markets. Here is an honest comparison based on material science, not sales preference.
PTFE
PolytetrafluoroethyleneWidest chemical resistance, highest heat tolerance, lowest friction. Opaque white. Requires sintering in manufacture.
PEEK
Polyether ether ketoneHighest mechanical strength, rigid, excellent fatigue resistance. Natural tan color. Thermoplastic.
PFA
Perfluoroalkoxy alkaneTransparent, flexible fluoropolymer. PTFE-level chemical resistance with melt-processable manufacturing.
Table of Contents
Full Comparison Table
| Property | PTFE | PEEK | PFA |
|---|---|---|---|
| Continuous service temp | 260°C (500°F) | 250°C (482°F) | 260°C (500°F) |
| Short-term peak temp | 300°C | 310°C | 310°C |
| Chemical resistance | Excellent (broadest) | Good (limited vs strong acids) | Excellent (= PTFE) |
| Tensile strength | 20-35 MPa | 100 MPa | 20-25 MPa |
| Flexibility | Moderate | Rigid | High |
| Transparency | Opaque/white | Tan/opaque | Transparent |
| Surface friction (CoF) | 0.05-0.10 (lowest) | 0.35-0.45 | 0.12-0.20 |
| Dielectric constant | 2.1 (excellent ESD) | 3.2 | 2.1 (excellent ESD) |
| Sterilization | Autoclave, EtO, gamma | Autoclave, EtO, gamma | Autoclave, EtO, gamma |
| Manufacturing | Sintering required | Extrusion (thermoplastic) | Extrusion (thermoplastic) |
| FDA compliant | Yes | Yes (implant grade available) | Yes |
| Relative cost | $ (lowest) | $$$ (highest) | $$ (moderate) |
PTFE Tubing: Strengths and Limitations
PTFE (polytetrafluoroethylene) is the original fluoropolymer and still the most widely used high-performance tubing material. Discovered by accident at DuPont in 1938 (sold commercially as Teflon®), PTFE's properties are the result of extraordinarily strong carbon-fluorine bonds.
Why PTFE excels
- Broadest chemical resistance: Resistant to virtually all solvents, acids, alkalis, and oxidizers. Only alkali metals (cesium, potassium metal) and certain fluorinating agents attack PTFE at elevated temperatures.
- Lowest friction coefficient: CoF of 0.05-0.10 is the lowest of any solid material. Fluids and particles slide through PTFE tubing with minimal wall adhesion.
- Excellent dielectric properties: Critical for ESD-safe applications in semiconductor fabs and electronics manufacturing.
- Cost: PTFE is significantly cheaper than PEEK and slightly cheaper than PFA for most dimensions.
PTFE limitations
- Opaque: You cannot visually inspect flow through PTFE tubing.
- Cold flow (creep): PTFE deforms under sustained load at room temperature, making it unsuitable for structural components under constant compression.
- Low mechanical strength: Not suitable for high-pressure applications without reinforcement.
- Sintering requirement: Cannot be melt-processed like a true thermoplastic, limiting the complexity of PTFE fittings.
Best for: Chemical fluid handling, low-friction liners, ESD-safe semiconductor applications, general-purpose laboratory tubing. See our PTFE tube specifications.
PEEK Tubing: Strengths and Limitations
PEEK (polyether ether ketone) is a semi-crystalline thermoplastic with mechanical properties far exceeding most other engineering plastics. It is the material of choice when you need a plastic that behaves more like metal: rigid, dimensionally stable under load, and fatigue-resistant.
Why PEEK excels
- Mechanical strength: Tensile strength of 100 MPa — roughly 3-4x that of PTFE or PFA. Critical for high-pressure chromatography (HPLC) tubing and structural components.
- Dimensional stability: PEEK doesn't creep under sustained load, unlike PTFE. Fittings remain tight over time.
- Radiation resistance: Maintains properties after high gamma radiation doses — relevant for nuclear applications and some medical device sterilization requirements.
- Machinability: PEEK machines cleanly with standard tools, enabling complex fitting designs.
PEEK limitations
- Limited chemical resistance vs fluoropolymers: PEEK is attacked by concentrated sulfuric acid, nitric acid, and some halogens. Not suitable for these chemicals at elevated temperatures.
- High cost: PEEK tubing typically costs 5-10x more than PTFE in equivalent dimensions.
- Opaque: Natural color is tan/brown. Colored PEEK (black, grey) is available but no transparent grades.
- UV degradation: PEEK is susceptible to UV degradation unless UV-stabilized or used in opaque/protected environments.
Best for: HPLC and high-pressure lab systems, implantable medical devices (PEEK implant grade), high-temperature structural components, semiconductor equipment mechanical parts.
PFA Tubing: Strengths and Limitations
PFA (perfluoroalkoxy alkane) was developed to solve PTFE's processability problem. By substituting perfluoroalkoxy side groups into the PTFE backbone, PFA retains PTFE's exceptional chemical resistance and temperature rating while becoming melt-processable like a conventional thermoplastic.
Why PFA excels
- Transparency: PFA is naturally transparent/translucent, enabling visual flow monitoring. Critical for semiconductor wet process tools where chemical mixing or air bubble detection matters.
- Same chemical resistance as PTFE: PFA's fluoropolymer chemistry is essentially identical to PTFE for practical purposes.
- Flexibility: PFA is significantly more flexible than PTFE of the same wall thickness, making it easier to route through tight spaces.
- Seamless fittings: Melt-processability allows PFA to be welded and formed into complex fitting geometries without joints — reducing particle generation, a critical requirement in semiconductor.
- Lower extractables: High-purity PFA grades (used in semiconductor) have extremely low extractable organic and ionic contamination.
PFA limitations
- Lower mechanical strength than PEEK: PFA has similar strength to PTFE, significantly less than PEEK.
- Higher cost than PTFE: PFA typically costs 30-60% more than PTFE in equivalent dimensions.
- Less widely stocked: Fewer distributors carry the full PFA dimension range compared to PTFE.
Best for: Semiconductor wet process systems, ultra-pure chemical handling, applications requiring visual flow monitoring, flexible routing in confined spaces. See our PFA tube specifications.
Selection by Application
➡ PFA first choice. Transparency, ultra-low extractables, and weld-ability for seamless fittings. PTFE for less critical lines. Also see our ESD-safe PFA tubing for charge-dissipative requirements.
➡ PTFE for general fluid handling. PEEK for structural/implant components. PFA where transparency is required. All three are FDA compliant; confirm specific grade requirements with your regulatory team.
➡ PTFE for corrosive chemical handling. Cost advantage is significant at scale. PEEK only where high pressure or mechanical load requires it. Check PEEK's chemical resistance limits for your specific chemicals — PTFE or PFA for concentrated acids.
➡ PEEK is the standard. High-pressure capability, dimensional stability at fittings, and compatibility with most HPLC solvents. Use PFA for compatibility with strong acids where PEEK is attacked.
➡ PTFE for most applications. PTFE's low friction and chemical inertness, combined with FDA compliance, make it the default. PFA where visual monitoring of flow is required.
➡ ESD-safe PTFE or ESD-safe PFA. Both materials have excellent dielectric properties; ESD-safe grades add carbon black or other additives for charge dissipation. See our ESD PFA tubing.
Cost Comparison
Relative cost varies by dimension and quantity, but the general pattern holds across markets:
- PTFE: Baseline cost. For a 4mm OD / 2mm ID tube, expect $1-3/m at commercial quantities.
- PFA: Typically 30-60% premium over PTFE. Higher for high-purity semiconductor grades.
- PEEK: Typically 5-10x PTFE cost. High-purity or implant-grade PEEK can be 20x or more.
For most applications where PTFE's properties are sufficient, specifying PEEK adds cost without benefit. The reverse is also true: using PTFE where PEEK's mechanical strength is required leads to field failures.
Common Material Selection Mistakes
1. Specifying PEEK for chemical resistance alone
Engineers unfamiliar with fluoropolymers sometimes specify PEEK for "high-performance chemical resistance." For strong acids and broad chemical compatibility, PTFE or PFA is actually superior to PEEK. PEEK's advantage is mechanical, not chemical.
2. Using PTFE where transparency is needed
PTFE is opaque. If your process requires visual confirmation of flow, liquid level, or bubble detection, PTFE won't work. PFA is the correct choice.
3. Ignoring cold flow in PTFE fittings
PTFE creeps under sustained compressive load. Fitting connections in PTFE will loosen over time if not properly designed with spring-back provisions. PEEK fittings don't have this problem. For critical fittings, use PEEK ferrules with PTFE tubing.
4. Not specifying purity grade for semiconductor
Generic PTFE or PFA contains additives that are unacceptable in semiconductor wet process. Semiconductor-grade PFA (sometimes called "HP" or "ultra-high purity" PFA) has controlled extractables and is qualified for fab use. Always specify purity grade when ordering for semiconductor applications.
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Can PTFE tubing be used with food contact?
Yes. PTFE is FDA compliant for food contact applications. Its chemical inertness means it won't leach into food products. PTFE is used in food processing equipment, dairy and beverage lines, and food-grade pneumatic systems. Confirm the specific grade with your supplier — food-grade PTFE must meet FDA 21 CFR 177.1550.
Is PEEK biocompatible for medical implants?
Yes, implant-grade PEEK (such as Invibio PEEK-OPTIMA) is ISO 10993 biocompatible and is widely used in spinal implants, orthopedic devices, and dental applications. Standard PEEK for industrial use is not the same as implant-grade PEEK — different specifications, different testing, different traceability.
What temperature can PFA handle in steam sterilization?
PFA can handle standard autoclave sterilization at 121°C (250°F) without deformation. For extended steam cycles or higher temperature steam (134°C), verify the specific PFA grade's autoclave rating with the manufacturer. PFA's 260°C continuous service temperature provides ample margin for standard autoclave cycles.
Can PTFE and PFA be welded together?
They should not be directly welded. PTFE cannot be melt-welded (requires sintering); PFA can. If you need to join PTFE and PFA in a system, use mechanical fittings rather than welded joints.