1) Raindrops have tension and are a tightly connected whole of water molecules. 2) The holes in the membrane of the jacket are very small, much smaller than raindrops, so raindrops cannot enter the small holes.
The internal tension of water droplets prevents them from entering the Teflon waterproof and breathable membrane.
Because the “tension” of raindrops is very strong, the water molecules are strongly attracted to each other, like clumping together.
When a raindrop touches the film, no water molecules want to leave the droplet.
Raindrops cannot enter the film.
Because the diameter of the small holes on the jacket film is generally only 10 microns (1 meter = 1 million microns), the diameter of the raindrops is about 20,000 times the diameter of these small holes, and it is bound to be unable to penetrate into the fabric through the small holes.
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