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How does EPTFE Breathable Membrane Film achieve dual functions of waterproofing and breathability

2025-12-27

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EPTFE Membrane: Dual-Function Technology

Understanding the material properties and microstructural design that enable waterproofing and breathability

The dual functions of waterproofing and breathability of EPTFE breathable membrane film are mainly realized through its unique material properties and microstructural design. EPTFE, a synthetic polymer, has inherent hydrophobicity, which lays the foundation for its waterproof performance.

Material Properties
EPTFE - Expanded Polytetrafluoroethylene
  • Unlike many conventional materials that easily absorb water, the molecular structure of EPTFE repels water molecules, preventing them from penetrating the membrane surface.
  • The key to balancing these two functions lies in the special micro porous structure formed during the membrane manufacturing process.
  • Through specific stretching and processing techniques, the EPTFE material forms a network of interconnected micro pores.
Microstructural Design
  • These pores play a decisive role in achieving breathability while maintaining waterproofing. The principle behind this is the difference in the size of water droplets and water vapor molecules.
  • Water droplets, whether from rain or other liquid sources, are relatively large in volume and cannot pass through the tiny pores of the EPTFE membrane.
  • In contrast, water vapor molecules generated by human perspiration or environmental humidity are much smaller, allowing them to freely diffuse through the porous network and escape to the outside.
Selective Permeability

This selective permeability ensures that the membrane can block liquid water effectively while enabling the passage of water vapor, thus achieving the dual effects of keeping the interior dry and preventing moisture accumulation.

Material Stability

In addition, the stability of the EPTFE material ensures that this dual functionality is maintained under various environmental conditions. Its resistance to chemical corrosion and temperature changes prevents the microstructure from being damaged, ensuring long-term reliable performance in both waterproofing and breathability without mutual interference between the two functions.