PHOTOCATALYTICALLY-ACTIVATED SELF-CLEANING ARTICLE AND METHOD OF MAKING SAME

摘要

A method and article are disclosed herein. The method comprises the steps of manufacturing a continuous glass float ribbon having a first major surface and an opposite major surface defined as a second major surface. The first major surface has tin diffused therein which is characteristic of forming a glass float ribbon on a molten tin bath. The next step comprises positioning a chemical vapour deposition coating apparatus over the surface of said glass float ribbon at a point in the manufacture of the glass float ribbon where the class float ribbon has a temperature of at least about 400.degree.C. The next step comprises directing a metal oxide precursor, namely, the titanium tetrachloride, titanium tetraisopropoxide or titanium tetraethoxide in a carrier gas stream through the chemical vapour deposition apparatus over a surface of the glass float ribbon. The next step comprises annealing the glass float ribbon to produce titanium dioxide in the crystalline phase as a photocatalytically-activated, self-cleaning coating over the glass float ribbon. The coating has a photocatalytically-activated self-cleaning reaction rate of least about 2.times.10 -3 cm-1min-1. The article is a photocatalytically-activated self-cleaning article of manufacture. Such. article comprises a substrate having at least one surfaceand containing sodium. Such article comprises a photocatalytically-activated, self-cleaning coating deposited over the surface of the substrate by chemical vapour deposition, or magnetron sputtered vacuum deposition or spray pyrolysis. The coating is at least 100 Angstroms. Such article comprises a sodium ion poisoning prevention layer which is either a sodium ion diffusion barrier layer disposed between the substrate and the photocatalytically-activated self-cleaning coating with a thickness of at least about 100 .ANG. to inhibit migration of sodium ions from the substrate to the photocatalytically- activated self-cleaning coating, or a fraction of the overall thickness of the photocatalytically-activated, self-cleaning coating, where the photocatalytically-activated, self-cleaning coating has a thickness that exceeds a minimum thickness so that they sodium ions are able to migrate only through the fraction of the overall thickness of the photocatalytically-activated, self-cleaning coating during any time period at which the temperature of the substrate exceeds a temperature which permits sodium ion migration, so that the thickness of the photocatalytically-activated, self-cleaning coating apposite from the substrate surface is able to maintain photocatalytically-activated self-cleaning coating activity. The photocatalytically-activated, self-cleaning coating has a photocatalytically-activated, self-cleaning reaction rate of at least about 2.times.10 -3 cm-1min-1.