Although PTFE (polytetrafluoroethylene) and ePTFE (expanded polytetrafluoroethylene) have the same chemical basis, they have significant differences in structure, performance and application areas.
Chemical structure and basic properties
Both PTFE and ePTFE are polymerized from tetrafluoroethylene monomers, and both have the chemical formula (CF₂-CF₂)ₙ, which are highly chemically inert and resistant to high temperatures. PTFE is formed by high-temperature sintering, and the molecular chains are closely arranged to form a dense, non-porous structure. ePTFE uses a special stretching process to make PTFE fiberize at high temperatures to form a porous mesh structure with a porosity of 70%-90%.
Comparison of physical properties
| Features | PTFE | ePTFE |
| Density | High (2.1-2.3 g/cm³) | Low (0.1-1.5 g/cm³) |
| Permeability | No permeability (completely dense) | High permeability (micropores allow gas diffusion) |
| Flexibility | Relatively hard and brittle | High flexibility and elasticity |
| Mechanical strength | High compressive strength, low tear resistance | Significantly improved tear resistance |
| Porosity | No pores | Porosity can reach 70%-90% |
Functional characteristics
● PTFE: It is chemically inert and resistant to strong acids, strong alkalis and organic solvents, has a temperature range of -200°C to +260°C, and has an extremely low dielectric constant (about 2.0), making it suitable for high-frequency circuit insulation.
● ePTFE: The microporous structure can achieve waterproof and breathable properties (such as the Gore-Tex principle), and is widely used in medical implants (such as vascular patches). The porous structure is suitable for sealing gaskets (rebound after compression to fill the gap).
Typical application scenarios
● PTFE: Suitable for high-temperature cable insulation, bearing lubrication coatings, chemical pipeline linings, and high-purity reactor linings in the semiconductor industry.
● ePTFE: In the cable field, it is used as the insulation layer of high-frequency communication cables, in the medical field, it is used for artificial blood vessels and sutures, and in the industrial field, it is used for fuel cell proton exchange membranes and air filtration materials.
PTFE and ePTFE each have their own advantages. PTFE is suitable for high temperature, high pressure, and chemically corrosive environments due to its superior heat resistance, chemical resistance, and low friction coefficient; ePTFE, with its flexibility, air permeability, and biocompatibility brought by its microporous structure, performs well in the medical, filtration, and dynamic sealing industries. The choice of material should be determined based on the needs of the specific application scenario.
What are the applications of ePTFE in the medical field?
ePTFE (expanded polytetrafluoroethylene) is widely used in the medical field, mainly due to its unique microporous structure, biocompatibility, non-toxic, non-sensitizing and non-carcinogenic properties. The following are its main applications:
1. Cardiovascular field
Artificial blood vessels: ePTFE is the most widely used synthetic material for artificial blood vessels, accounting for about 60%. Its microporous structure allows human tissue cells and blood vessels to grow in it, forming a connection close to autologous tissue, thereby improving the healing rate and durability of artificial blood vessels.
Heart patch: used to repair heart tissue, such as pericardium. ePTFE heart patch can prevent adhesion between the heart and sternum tissue, reducing the risk of secondary surgery.
Vascular stent: ePTFE can be used to make the coating of vascular stents, and its good biocompatibility and mechanical properties help reduce inflammation and thrombosis.
2. Plastic surgery
Facial implants: ePTFE can be used to make facial plastic materials, such as rhinoplasty and facial fillers. Its microporous structure helps tissue growth and reduces rejection.
Orthopedic implants: In the field of orthopedics, ePTFE can be used to manufacture joint implants, and its good wear resistance and biocompatibility help to increase the service life of implants.
3. Other applications
Hernia patches: Hernia patches made of ePTFE can effectively prevent hernia recurrence, and its porous structure helps tissue integration.
Medical sutures: ePTFE sutures have good flexibility and tensile strength, which can reduce tissue adhesion after surgery.
Heart valves: ePTFE can be used to manufacture heart valves, and its durability and biocompatibility help to increase the service life of valves.
4. Medical device coatings
ePTFE can also be used for coatings of medical devices, such as catheters and surgical instruments. Its low coefficient of friction and biocompatibility help reduce tissue damage during surgery
Post time: Apr-27-2025