Silica coating for enhanced hydrophilicity/transmittivity

摘要

A method of coating with an aqueous coating composition having a pH <5 of silica nanoparticles having a, average particle diameter of ≦40 nm, silica nanoparticles having an average particle diameter of ≧50 nm, and a tetraalkoxysilane. The resulting coatings are substantially uniform in thickness, durably adheres to the substrate, and provides antireflection and or hydrophilic surface properties to the substrate.

主权项

1. A method of providing a coating to a substrate comprising providing a coating composition consisting of:
a) 0.5 to 99 wt. % water b) 0.1 to 20 wt. % silica nanoparticles having an average particle diameter of 40 nm or less, c) 0 to 20 wt. % silica nanoparticles having an average particle diameter of 50 nm or more, wherein the sum of b) and c) is 0.1 to 20 wt. %; d) a sufficient amount of an acid having a pKa of <3.5 to reduce the pH to less than 5; e) 0 to 20 percent by weight of a tetraalkoxysilane, relative to the amount of the silica nanoparticle;
wherein the sum of the weight percents of components a) to e) is 100 wt. % of the coating composition; contacting a substrate with the coating composition consisting of a) to e) is 100 wt. % of the coating composition; contacting a substrate with the coating composition consisting of a) to e); and drying to provide a silica nanoparticle coating.