Hydrophilic coatings and films
In contrast to microporous films, the hydrophilic films are continuous pore-free solid films. As such, they have the potential for high resistance to ingress of liquids, provided that they are free from pin-holes and that the film has a certain minimum thickness. However, water-vapour permeability rates through hydrophilic films are inversely proportional to their thickness.
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The pink layer represents the skin and the pale blue spots represent water "vapour" molecules. Water molecules are small enough to pass through the spaces between the molecules of the polymer film. The red line represents a polymer molecule with blue hydrophilic groups which attract the water molecules. Under appropriate conditions the water molecules diffuse through the film and escape into the air.
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