Master mold for pattern transfer
In various embodiments, the present invention provides a method comprising: disposing upon a first substrate, a first coating; texturing the first coating with a stamp; treating the textured first coating to form a master mold; where the master mold contains a mirror image of the texture contained in the first coating; and transferring the texture from the master mold to a second substrate.
1. A method comprising:
disposing upon a first substrate, a first coating comprising metal oxide nanoparticles dispersed in a solvent, wherein the metal oxide nanoparticles are 80 wt % or more of the first coating;
texturing the first coating with a microporous solvent-permeable stamp, wherein the stamp is an elastomeric stamp that comprises a texture and has micropores that absorb the solvent, the stamp extracts the solvent from the first coating while texturing the coating, and the texturing is performed in a high humidity environment, wherein the high humidity environment has a relative humidity of 70% or more;
transferring solvent away from the textured first coating with the microporous solvent-permeable stamp until the first coating is substantially devoid of the solvent;
treating the textured first coating to form a master mold;
wherein the master mold contains a mirror image of the texture contained in the textured, solvent-permeable stamp; and
transferring the texture from the master mold to a second substrate.
2. The method of claim 1 , wherein treating the textured first coating comprises calcining and the resulting master mold comprises metal oxide pillars with aspect ratios of 5:1 or greater.
3. The method of claim 1 , wherein the second substrate comprises a second coating disposed thereon.
4. The method of claim 1 , wherein the first coating comprises 10 to 50 wt % of a sol-gel and comprises a metal oxide precursor sol.
5. The method of claim 1 , wherein the textured first coating comprises architectural elements having an aspect ratio of greater than 5:1.
6. The method of claim 1 , wherein the first coating comprises nanoparticles having an average particle size of less than 100 nanometers.
7. The method of claim 6 , wherein the nanoparticles comprise titania, silica, zirconia, ceria, indium titanium oxide, tin oxide, indium oxide, antimony oxide, or a combination thereof, and the first coating further comprises one or more of nanoparticle precursor, polymer, or polymer precursor.
8. The method of claim 4 , wherein the metal oxide precursor is titanium isopropoxide, titanium butoxide, tetraethoxysilane, tetramethoxysilane, vinyltrialoxysilanes, vinyltrimethoxysilane, aluminum sec-butoxide, zirconium isopropoxide, cerium isopropoxide, acetylacetonate titanate chelate, triethanolamine titanate chelate, lactic acid titanate chelate, zirconate chelates, zirconium propionate, or a combination thereof.
9. The method of claim 1 , comprising treating the textured first coating with electromagnetic radiation; wherein the electromagnetic radiation comprises at least one of heat at 200 to 2000° C., microwave radiation, near infrared radiation, ultraviolet radiation, and an electron beam.
10. The method of claim 1 , wherein transferring the solvent away is performed by diffusing the solvent through the textured solvent-permeable stamp, the stamp is operative to extract the solvent from the first coating, the stamp comprises a composite polydimethylsiloxane (PDMS) stamp, which comprises a h-PDMS layer comprising the texture, a backing layer that provides support for the h-PDMS layer, and wherein the stamp is heated to a temperature of 30 to 250° C. while the stamp is in contact with the first coating.
11. The method of claim 1 , wherein the stamp is an elastomeric stamp that is operative to extract a portion of solvent from the first coating and comprises a polysiloxane, a polybutadiene, a polyisoprene, a styrene-butadiene rubber, a poly(styrene)-block-poly(butadiene), a poly(acrylonitrile)-block-poly(styrene)-block-poly(butadiene) (ABS), a polychloroprene, an epichlorohydrin rubber, a polyacrylic rubber, a fluorosilicone elastomer, a fluoroelastomer, a perfluoroelastomer, a polyether block amides (PEBA), a chlorosulfonated polyethylene, an ethylene propylene diene rubber (EPR), an ethylene-vinyl acetate elastomer, or a combination thereof.
12. The method of claim 1 , wherein the substrate comprises a metal, a polymer or a ceramic.
13. The method of claim 12 , wherein the metal comprises steel, brass, bronze, nickel, iron, aluminum, titanium, copper, cobalt, or a combination thereof; the polymer comprises polyolefins, polysiloxanes, polyfluoroethylenes, polyacrylates, polystyrenes, polyimides, polyesters, or a combination thereof; and the ceramic comprises silica, alumina, titania, quartz, zirconia, ceria, or a combination thereof.
14. The method of claim 1 , wherein the substrate is flexible.
15. The method of claim 1 , wherein the second coating comprises thermoplastic polymers, thermosetting polymers, blends of thermoplastic polymers, blends of thermosetting polymers, and blends of thermoplastic polymers with thermosetting polymers; and the polymers are selected from the group of polyacetals, polyacrylics, polycarbonates polystyrenes, polyesters, polyamides, polyamideimides, polyarylates, polyacrylates, polymethylmethacrylates, polyarylsulfones, polyethersulfones, polyphenylene sulfides, polyvinyl chlorides, polysulfones, polyimides, polyetherimides, polytetrafluoroethylenes, polyetherketones, polyether etherketones, polyether ketone ketones, polybenzoxazoles, polyoxadiazoles, polybenzothiazinophenothiazines, polybenzothiazoles, polypyrazinoquinoxalines, polypyromellitimides, polyquinoxalines, polybenzimidazoles, polyoxindoles, polyoxoisoindolines, polydioxoisoindolines, polytriazines, polypyridazines, polypiperazines, polypyridines, polypiperidines, polytriazoles, polypyrazoles, polypyrrolidines, polycarboranes, polyoxabicyclononanes, polydibenzofurans, polyphthalides, polyacetals, polyanhydrides, polyvinyl ethers, polyvinyl thioethers, polyvinyl alcohols, polyvinyl ketones, polyvinyl halides, polyvinyl nitriles, polyvinyl esters, polysulfonates, polysulfides, polythioesters, polysulfones, polysulfonamides, polyureas, polyphosphazenes, polysilazanes, polysiloxanes, polyolefins, polyacrylamides, epoxy polymers, unsaturated polyester polymers, polyimide polymers, bismaleimide polymers, bismaleimide triazine polymers, cyanate ester polymers, vinyl polymers, benzoxazine polymers, benzocyclobutene polymers, acrylics, alkyds, phenol-formaldehyde polymers, novolacs, resoles, melamine-formaldehyde polymers, urea-formaldehyde polymers, hydroxymethylfurans, isocyanates, unsaturated polyesterimides, or a combination thereof.
16. The method of claim 1 , wherein the second coating comprises a crosslinkable polymer and the crosslinkable polymer can be crosslinked using thermal energy, radiation, or a combination thereof.
17. The method of claim 1 , wherein the solvent is NMP, ethanol, methanol or 1,2-propane diol, or a mixture thereof.
18. The method of claim 1 , wherein transferring the solvent away is performed by diffusing the solvent through the textured solvent-permeable stamp, the stamp is a composite polydimethylsiloxane (PDMS) stamp, which comprises two layers of elastomer: an elastomer backing layer, and an elastomer texturing layer, wherein the backing layer provides support for the texturing layer, and the texturing layer is thinner and harder than the backing layer, and wherein the stamp comprises recesses to facilitate filling the stamp with the solvent.
19. The method of claim 1 , wherein texturing the first coating is performed at a 70-80% relative humidity environment.
20. A method for residual-layer free imprinting comprising:
disposing upon a first substrate, a first coating comprising metal oxide nanoparticles dispersed in a solvent, wherein the metal oxide nanoparticles are 80 wt % or more of the first coating;
texturing the first coating while transferring the solvent away from the first coating by using a microporous solvent-permeable stamp, wherein the stamp is an elastomeric stamp comprising: a texture configured for texturing the first coating, surface contact angles configured for dewetting the solvent, and micropores configured for absorbing the solvent and diffusing the solvent through the stamp and away from the first coating;
transferring solvent away from the textured first coating until the first coating is substantially devoid of the solvent; and
calcining the textured first coating to form a residual-layer free master mold.