Hydrophobic Coatings

thin layers of a waterproof substance on the surface of hydrophilic materials. Hydrophobic coatings are often called water-repellent, which is incorrect, since the water molecules are attracted to the coatings, although extremely weakly, rather than repelled by them.

Hydrophobic coatings are produced in the form of monomolecular layers (adsorbed orientated layers one molecule thick) or lacquer films by treating a material with solutions, emulsions, or less frequently, vapors of hydrophobic agents, which are substances that interact weakly with water but attach themselves firmly to a surface. Substances used as hydrophobic agents include salts of fatty acids and such metals as copper, aluminum, and zirconium; cation-active surface-active agents; and low-and high-molecular-weight organosilicon and organic fluorine compounds.

Hydrophobic coatings protect various materials (metal, wood, plastics, leather, and fabric and nonfabric fibrous ma-terials) from the destructive action of water or wetting. They are used particularly extensively in machine building,construction, and textile production.