Thin film hydrophilic coatings

Abstract

A hydrophilic coating composition used to impart increased lubricity and wettability to the surface of a hydrophobic substrate which is comprised of three essential components: 1) Hydrogel-forming polymer component A 2) Water-soluble polymer component B 3) Common solvent C for the components A and B The water-insoluble, hydrogel-forming component A consists of a segmented copolymer with long, hydrophilic terminal blocks and the essentially hydrophobic central section. The two polymer components A and B have a limited miscibility in the absence of a common solvent C. Therefore, their blend tends to separate spontaneously into two polymer phases. The phase separation takes place during the solvent evaporation or extraction. A gradient of hydrophilicity and swelling within the coating layer is thus spontaneously created achieving a good adhesion to the substrate and high surface hydrophilicity at the same time.

Dependencies are inferred from the claim text.