Titania coating and method of making same
View Patent ↗Methods of making titania coatings having self cleaning properties, and associated articles are provided. In certain example instances, a substrate supports a layer comprising titanium dioxide. The substrate may support multiple layers. In certain examples, the titanium dioxide layer is made using a process involving a titania precursor and a photomonomer. The titanium dioxide coating may be applied as a liquid directly or indirectly on a substrate, then permitted to cure. After curing using ultraviolet radiation and/or electron beams, the resulting coating may inhibit fouling, be antireflective, be highly durable, self cleaning and/or hydrophilic in certain instances.
1. A method of making a coated article comprising an antireflection coating, the method comprising:
mixing a photomonomer comprising at least one radiation curable monomer capable of polymerization through exposure to ultraviolet radiation or electron beam with a titanium alkoxide to form a mixture;
applying the mixture directly or indirectly on a substrate to form a layer covering substantially all of a major surface of the substrate;
first curing the layer by exposing substantially all of an outer surface of the layer to ultraviolet radiation or electron beam after its application for about 5 to 120 seconds; and
subsequently firing the cured layer, so as to form an antireflection coating comprising at least a titania-inclusive layer on the substrate.
2. The method of claim 1 , wherein the titanium alkoxide comprises titanium tetra n-butoxide.
3. The method of claim 1 , wherein the step of mixing the photomonomer with the titanium alkoxide further includes mixing a silane.
4. The method of claim 3 , wherein the silane comprises 3-methacryloxypropyl trimethoxysilane.
5. The method of claim 1 , wherein the step of mixing the photomonomer with the titanium alkoxide further includes mixing at least one solvent.
6. The method of claim 5 , wherein the at least one solvent comprises n_propanol and methyl ethyl ketone.
7. The method of claim 1 , wherein the mixture comprises titanium alkoxide in an amount up to 10% by weight, in a concentration expressed in terms of titanium dioxide, of the mixture.
8. The method of claim 1 , further comprising the step of forming a high index layer, a low index layer, or a medium index layer between the layer and the substrate.
9. The method of claim 1 , wherein the substrate comprises a glass substrate.
10. The method of claim 1 , wherein the step of firing the layer is carried out at a temperature of from about 550 to 700° C. for a duration of from about 1 to 10 minutes.
11. A method of making a coated article comprising an antireflection coating, the method comprising: mixing a photomonomer comprising at least one radiation curable monomer capable of polymerization through exposure to ultraviolet radiation or electron beam with a titanium alkoxide and a silane to form a mixture; applying the mixture directly or indirectly on a substrate to form a layer, wherein the layer substantially entirely covers a major surface of the substrate; and curing the layer through exposure of substantially all of an outermost surface of the layer to ultraviolet radiation or electron beam after its application for about 5 to 120 seconds, so as to form an antireflective coating comprising a titania and silica-inclusive layer on the substrate, wherein a molar ratio of titania to silica is from about 80:40 to 60:20; and after said curing, firing the layer in an oven.
12. The method of claim 11 , wherein the coating layer is fired in an oven at a temperature of from about 550 to 700° C. for a duration of from about 1 to 10 minutes.