The waterproof and moisture permeability of PTFE film depends on the structure of the film and the wettability of the surface. The morphology and structure of the film have the greatest influence on the waterproof and moisture permeability.
As long as the micropore diameter of the PTFE film is controlled by a process of several microns or below, the water droplets can be prevented directly through, and the water vapor is allowed to pass through. With an average of about 1 billion 400 million /em2 microporous non concentric staggered PTFE film porosity, at around 90%, the diameter of 0.2 mu m or less than the diameter of the water molecule, hundreds of times, even thousands of times, thousands or even tens of thousands of times than the water fraction, these pores can stop the infiltration of water, and steam molecules of human sweat it can freely outward dissipation, also because the bend longitudinal specifications of the extreme small hole, the wind can not through, which has the characteristics of good wind and warm. On the other hand, because the surface energy of the tetrafluoroethylene material is very low, the contact angle is greater than 90 degrees, and it can prevent liquid water from wetting and capillary penetration. Therefore, the PTFE membrane has the function of waterproof and moisture permeability.