Introduction: The Critical Role of Friction in Medical Tubing and Liners
In modern minimally invasive medicine, success is often measured in millimeters and by how much friction a device creates. Physicians use instruments to navigate through narrow, twisting blood vessels to deliver drugs or position devices to improve a patient’s quality of life. The medical tubing through which they pass must produce minimal friction and provide smooth, predictable routing into and through the body.
Friction is the invisible force that can determine whether a procedure will be successful or a failure. Introducing medical devices can generate high levels of friction that requires increased force to insert them into the body. Friction also creates additional difficulty in advancing and navigating the device, increases the possibility of damage to the patient, and adds difficulty in performing precise work.
Medical devices are becoming increasing complex. In turn, manufacturers need to supply them with materials that have very low levels of friction.1
One of the many polymers/engineered materials currently in use is Polytetrafluoroethylene (PTFE). PTFE was first used for medical applications more than 40 years ago. However, it continues to be considered a benchmark standard for low-friction performance for catheter liners and precision tubing.2,3
Why is PTFE low friction medical tubing such an effective material? PTFE has exceptionally low levels of friction due to its unique chemistry, molecular configuration, and surface characteristics. This low friction property gives the physician the ability to navigate devices smoothly and safely during minimally invasive procedures, among other benefits.
In this article we dive into the science of PTFE medical tubing and liners to see why it remains the gold standard for low-friction medical tubing applications.
Understanding PTFE: A Unique Fluoropolymer
Polytetrafluoroethylene (PTFE) is created artificially from a series of recurring tetrafluoroethylene units. The backbone of the polytetrafluoroethylene is composed of carbon atoms that are surrounded by fluorine atoms. These carbon-fluorine bonds form some of the strongest bonds known to man in organic chemistry. 4
PTFE’s simple structure provides this material with several unique characteristics, including:
- Very low surface energy
- Almost complete resistance to chemicals
- High thermal stability (it stays stable at high temperatures)
- Very slippery surface (excellent lubricity)
PTFE is significantly different than most other conventional plastics (e.g., nylon and polyurethane). This is due to the fact that its surface has significantly less molecular attraction as compared to other surface types. This results in less friction created when different surfaces come in contact with one another.
The Science of Low Friction: Why PTFE Is So “Slippery”
Below we briefly explore the different reasons why this material is inherently low-friction.
Molecular Structure and Chemical Stability
PTFE’s distinct properties are derived from its very symmetrical molecular structure that consists of a large number of repeating –CF₂–CF₂– units. In this structure, every carbon atom is surrounded by fluorine atoms, thus providing a protective coating around them. These carbon–fluorine bonds (one of the strongest covalent bonds known) provide the backbone of the polymer with outstanding chemical stability and inertness. They also act to physically isolate the carbon chain from the surrounding environment. 2,5
Low Surface Energy and Non-Stick Behavior
PTFE has one of the lowest surface energies of any solid material. Thus, PTFE has a very low tendency to stick to another material. The low surface energy of PTFE causes it to have poor wettability. Therefore, when a liquid contacts a surface made of PTFE, the liquid does not spread, but beads up. In addition, the low surface energy of PTFE causes it to have a very low level of adhesion to solid materials. This is responsible for PTFE’s well-known non-stick properties.1
Weak Intermolecular Interactions
The intermolecular forces in PTFE are primarily weak van der Waals forces. This means that there are no significant contributions from either dipole-dipole or hydrogen bonding interactions because of PTFE’s symmetrical structure. There are minimal cohesive and adhesive forces between the molecular chains in PTFE and between the surfaces in contact with one another. This is due to these weak intermolecular attractive interactions. As such, the molecular chains and contacting surfaces can move freely with little or no resistance to the motion.5
Surface Smoothness and Non-Polarity
The surface has been made smooth and non-polar through the presence of fluorine atoms. These reduce mechanical entanglement at the microscopic scale. This structural aspect contributes to improving the material’s friction and adhesion resistance by continuing its slippery characteristics.2
Self-Lubricating Properties and Applications
PTFE has intrinsic self-lubricating properties. It also has a very low coefficient of friction due to its molecular and surface characteristics. As such, PTFE is ideal for use where decreased wear and resistance are needed. Examples include non-stick coatings, medical devices, medical tubing and liners, and industrial seals.
Non-Stick Behavior and Reduced Adhesion
PTFE has an extremely low surface energy, preventing most proteins, fats, and other biological substances from sticking to it easily. In the area of medical applications, this characteristic is very important because it:
- Decreases the risk of blood clots forming
- Helps prevent biofouling (the accumulation of unwanted biological products)
- Maintain the patency of the tubing.
Because PTFE tubing is non-stick, it allows fluid to flow easily and helps prevent buildup that would cause blockage or dosing errors. 2,6
Other Properties of PTFE That Make it Useful for Medical Devices
PTFE Low Friction Medical Tubing has other key properties, such as chemical inertness and biocompatibility that make it a great fit for medical use. We cover each of them in more detail below.
1. Chemical Inertness: PTFE’s Stability in Complex Biological Environments
PTFE is predominantly used in the manufacturing of components used in the medical field. One of its greatest benefits is that it is nearly completely chemically inert.7
PTFE can withstand:
- Strong acids and bases
- Organic solvents
- Oxidizing agents
- Biological fluids
In medical tubing applications, this translates to the following benefits of PTFE tubing:
- No degradation when exposed to drugs or contrast agents
- No leaching or contamination
- Long-term material stability
PTFE retains its physical structure even in a very corrosive chemical environments. This is unlike many other plastics, which often swell, break down, or react chemically when subjected to various chemicals.
This is one of the reasons PTFE is widely used in:
- Catheter liners
- Drug delivery systems
- Diagnostic tubing
- And more
2. Thermal Stability: Performance Across Extreme Conditions
PTFE exhibits an exceptionally wide operating temperature range. This ensures:
- Stability during sterilization (autoclave, gas-sterilization)
- Reliability in both cryogenic and elevated temperature conditions
- Consistent mechanical performance
For medical device manufacturers, this flexibility simplifies processing and ensures compatibility with various sterilization methods.7
3. Biocompatibility and Safety
PTFE has a long history of safe use in medical applications. 6,8
Similar to other medical-grade, lubricous technologies, such as hydrophilic coatings, PTFE has some key advantages, such as:
- Biocompatibility
- Non-toxicity
- Minimal immune response
Because it is chemically inert and non-reactive, PTFE does not interact adversely with tissues or fluids. This makes it suitable for both short-term and long-term medical use.
Expanded forms of PTFE are even used in:
- Vascular grafts
- Surgical implants
- Tissue engineering scaffolds
4. Flow Efficiency: The Hidden Impact of Low Friction
Low friction is not just about ease of movement; it also directly impacts fluid dynamics.2,3
PTFE tubing and liners reduce:
- Flow resistance
- Pressure drop
- Energy requirements
Studies show that PTFE tubing can significantly reduce hydraulic resistance compared to conventional materials.
This leads to the following benefits:
- More accurate fluid delivery
- Improved dosing precision
- Reduced pump strain
In microcatheters and narrow-lumen devices, these advantages become even more critical.
Precision Manufacturing: Enabling High-Performance PTFE Tubing and Liners
PTFE cannot be melt-processed like conventional thermoplastics. Instead, it is manufactured using specialized processes such as:
- Ram extrusion
- Paste extrusion
- Sintering
These methods allow for:
- Extremely tight tolerances
- Thin-wall construction
- Smooth internal surfaces
Film-cast PTFE liners, for example, are commonly used in advanced catheter systems where precision and lubricity are paramount. 9,10
The Role of PTFE in Modern Medical Devices
Today, PTFE is a foundational material in a wide range of devices. These include:
- Tubing and liners
- Catheters and microcatheters
- Guidewire jackets and coated guidewire systems
- Sheaths and introducers
- Drug delivery systems
- Diagnostic tubing
Its role is especially critical in minimally invasive procedures, in which device performance must be both precise and reliable.11
Utilizing PTFE and Hydrophilic Coatings to Achieve Low Friction Devices
PTFE’s inherent low-friction properties can be enhanced when combined with hydrophilic coatings.12,13 There is a complimentary relationship between these two technologies. The use of both PTFE and hydrophilic coatings can help OEMs create lubricious medical device products. Let us look at some of the reasons why.
The benefits of hydrophilic coatings, such as those by Hydromer®, Inc. include:
- Ultra-low wet friction
- Improved lubricity in aqueous environments
- Enhanced patient comfort
These two products provide device manufacturers with complementary benefits. They have great value in creating low friction devices in the following areas:
- Neurovascular devices
- Cardiovascular catheters
- Long-duration procedures
For companies such as Hydromer, who offer both, the synergy between PTFE and hydrophilic coatings is a strategic opportunity to help device manufacturers achieve lubricity for devices and systems.
Why PTFE Remains the Gold Standard in Medical Tubing
PTFE remains the leading low-friction medical tubing material even after many years of innovation in polymer science. This is true because:
- Unmatched Lubricity: No other polymer consistently achieves such low friction without external additives
- Proven Clinical Performance: Its long track record of safety and reliability backs it up
- Chemical and Thermal Stability: PTFE performs under conditions that degrade other materials
- Versatility: It can be used across a wide range of device types and applications
- Compatibility and Complimentary Nature with Advanced Coatings: PTFE serves as an ideal platform for further surface enhancement
Innovation Trends: The Future of PTFE in Medical Tubing
While new materials continue to emerge, PTFE is not being replaced. Instead is being enhanced via innovation by companies such as Hydromer®, Inc.
Key trends in PTFE medical tubing innovation include:
- Multi-layer tubing designs
- Hybrid materials combining PTFE with structural polymers
- Advanced coating technologies
- Improved processing techniques for thinner, stronger liners
Rather than losing relevance, PTFE tubings and liners are evolving alongside modern medical device innovation.
Enhancing Device Performance with PTFE Liners and Hydrophilic Coating Technologies
PTFE provides exceptional inherent lubricity. However, Hydromer extends the performance of its PTFE tubing and liners through advanced engineering of both the material and its surface. Our company uses innovative approaches to create PTFE products that include:
- free and mandrel extrusion
- Film-casting processes
- Ram extrusion
We are able to develop extremely thin liners having the following properties:
- high uniformity with tight tolerances
- optimized wall thicknesses
- customized flexibility that can be very demanding in catheter and tubing applications
The technology that supports the production of these PTFE liners enables device designers to effectively manage pushability, kink resistance, and trackability without sacrificing any of the low-friction benefits provided by PTFE.
In addition, our Hydromer® Hydrophilic Medical Device Coatings have excellent lubricity in wet environments. These surface coatings are activated upon hydration and form a thin, hydration layer that reduces friction at the tissue interface.
The combination of our innovative, precision-engineered PTFE liners and advanced Hydrophilic Coatings creates a complementary benefit for medical device manufacturers. Hydromer’s products can enable the next generation of minimally invasive devices, where both the material properties and surface interactions of these products must be optimized for success in the clinical setting.
Conclusion
PTFE has become the most popular material for low-friction medical tubing products. This is due to its unique blend of chemistry, physics, and engineering. It is ideally suited for tough and demanding medical applications due to its low coefficient of friction, chemical inertness, non-stick properties, and high degree of thermal stability. PTFE will remain the benchmark standard by which all other medical tubing materials are evaluated and compared to. Manufacturers of medical devices have already determined that they will use PTFE; the question now becomes, “How can PTFE be optimized or improved to develop new products?” Advanced coating technologies and innovations from material science will help shape the future of low-friction medical tubing.
References
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1. Narayan RJ. Friction and Wear of Medical Implants and Prosthetic Devices. Vol 23: ASM International; 2012:187-195.
2. Dhanumalayan E, Joshi GM. Performance properties and applications of polytetrafluoroethylene (PTFE)—a review. Advanced Composites and Hybrid Materials. 2018;1(2):247-268.
3. Roina Y, Auber F, Hocquet D, Herlem G. ePTFE‐based biomedical devices: An overview of surgical efficiency. Journal of Biomedical Materials Research Part B: Applied Biomaterials. 2022;110(2):302-320.
4. Ameduri B. The promising future of fluoropolymers. Macromolecular Chemistry and Physics. 2020;221(8):1900573.
5. Puts GJ, Crouse P, Ameduri BM. Polytetrafluoroethylene: synthesis and characterization of the original extreme polymer. Chemical reviews. 2019;119(3):1763-1805.
6. Luu CH, Nguyen NT, Ta HT. Unravelling Surface Modification Strategies for Preventing Medical Device-Induced Thrombosis. Advanced healthcare materials. Jan 2024;13(1):e2301039.
7. Renfrew MM, Lewis EE. Polytetrafluoroethylene. Heat resistant, chemically inert plastic. Industrial & Engineering Chemistry. 1946;38(9):870-877.
8. Chen M, Zamora PO, Som P, Peña LA, Osaki S. Cell attachment and biocompatibility of polytetrafluoroethylene (PTFE) treated with glow-discharge plasma of mixed ammonia and oxygen. Journal of Biomaterials Science, Polymer Edition. 2003;14(9):917-935.
9. Huang R, Hsu PS, Kuo CY, Chung Chen S, Lai JY, Lee LJ. Paste extrusion control and its influence on pore size properties of PTFE membranes. Advances in Polymer Technology: Journal of the Polymer Processing Institute. 2007;26(3):163-172.
10. Ariawan AB. Paste extrusion of polytetrafluoroethylene fine powder resins. 2002.
11. Hydromer. PTFE Liners and Tubings. 2025; https://hydromer.com/ptfe-liners-and-tubing/.
12. Qiang R, He Y, Yang Z, Luo H, Gao J, Long H. Hydrophilic modification of polytetrafluoroethylene particles and corrosion resistance of electroplated composite coatings. Results in Surfaces and Interfaces. 2025/08/01/ 2025;20:100573.
13. Asrafali SP, Periyasamy T, Kim S-C. Hydrophilic Nature of Polytetrafluoroethylene through Modification with Perfluorosulfonic Acid-Based Polymers. Sustainability. 2023;15(23):16479.
