Titanium dioxide coatings having roughened surfaces and methods of forming titanium dioxide coatings having roughened surfaces
View Patent ↗Methods for forming surface roughened titanium dioxide coatings are disclosed. Sol-gel compositions may be prepared having colloidal metal oxide particles and/or colloidal silica particles, formed on a substrate, and subsequently the coated substrate may be heated at a temperature sufficient to form a surface roughened anatase titanium dioxide coating. Surface roughened titanium dioxide coatings having at least one of improved antimicrobial properties, self-cleaning properties, hydrophilicity, and/or activation time are also disclosed. Substrates comprising such coatings are also disclosed.
1. A method of forming an anatase titanium dioxide coating having a roughened surface on a substrate, comprising:
preparing a titanium dioxide sol-gel composition;
adding colloidal silica particles to the titanium dioxide sol-gel composition to form a combined titanium dioxide and colloidal silica sol-gel composition, wherein the colloidal silica particles have an average particle size of about 70 nm to about 100 nm;
coating the substrate with the combined sol-gel composition; and
heating the coated substrate at a temperature ranging from about 550° C. to about 650° C. to form a surface roughened anatase titanium dioxide coating;
wherein the surface roughened titanium dioxide coating has a mean square roughness ranging from about 8 nm to about 12 nm; and
wherein the combined titanium dioxide and colloidal silica sol-gel composition comprises colloidal silica in an amount less than or equal to about 20 wt % relative to a total weight of the sol-gel composition.
2. The method of claim 1 , wherein the combined titanium dioxide and colloidal silica sol-gel composition comprises at least 5 wt % of said colloidal silica particles relative to the total weight of the sol-gel composition.
3. The method of claim 1 , wherein the substrate comprises a glass substrate.
4. The method of claim 3 , wherein the glass substrate is chosen from clear glass and low-iron glass substrates.
5. A method of improving at least one of antimicrobial properties, self-cleaning properties, hydrophilicity, and activation time of a titanium dioxide coating, comprising:
preparing a titanium dioxide sol-gel composition;
adding colloidal silica particles to the titanium dioxide sol-gel composition to form a combined titanium dioxide and colloidal silica sol-gel composition, wherein the colloidal silica particles have an average particle size of about 70 nm to about 100 nm;
coating a substrate with the combined sol-gel composition; and
heating the coated substrate at a temperature ranging from about 550° C. to about 650° C. to form a surface roughened anatase titanium dioxide coating;
wherein the surface roughened titanium dioxide coating has a mean square roughness ranging from about 8 nm to about 12 nm; and
wherein the combined titanium dioxide and colloidal silica sol-gel composition comprises colloidal silica in an amount less than or equal to about 20 wt % relative to a total weight of the sol-gel composition.
6. The method of claim 5 , wherein the combined titanium dioxide and colloidal silica sol-gel composition comprises at least 5 wt % colloidal silica particles relative to the total weight of the sol-gel composition.
7. The method of claim 5 , wherein the substrate is chosen from clear glass and low-iron glass.
8. The method of claim 1 , wherein the titanium dioxide sol-gel composition comprises a titanium alkoxide or a titanium chloride.
9. The method of claim 5 , wherein the titanium dioxide sol-gel composition comprises a titanium alkoxide or a titanium chloride.
10. The method of claim 1 , wherein the combined titanium dioxide and colloidal silica sol-gel composition comprises colloidal silica in an amount less than or equal to about 15 wt % relative to the total weight of the sol-gel composition.
11. The method of claim 5 , wherein the combined titanium dioxide and colloidal silica sol-gel composition comprises colloidal silica in an amount less than or equal to about 15 wt % relative to the total weight of the sol-gel composition.
12. The method of claim 1 , wherein the combined titanium dioxide and colloidal silica sol-gel composition comprises colloidal silica in an amount of about 5 wt % to about 15 wt % relative to the total weight of the sol-gel composition.
13. The method of claim 5 , wherein the combined titanium dioxide and colloidal silica sol-gel composition comprises colloidal silica in an amount of about 5 wt % to about 15 wt % relative to the total weight of the sol-gel composition.