Method of making a nanostructure and nanostructured articles
A method of making a nanostructure and nanostructured articles by depositing a layer to a major surface of a substrate by plasma chemical vapor deposition from a gaseous mixture while substantially simultaneously etching the surface with a reactive species. The method includes providing a substrate; mixing a first gaseous species capable of depositing a layer onto the substrate when formed into a plasma, with a second gaseous species capable of etching the substrate when formed into a plasma, thereby forming a gaseous mixture; forming the gaseous mixture into a plasma; and exposing a surface of the substrate to the plasma, wherein the surface is etched and a layer is deposited on at least a portion of the etched surface substantially simultaneously, thereby forming the nanostructure. The substrate can be a (co)polymeric material, an inorganic material, an alloy, a solid solution, or a combination thereof. The deposited layer can include the reaction product of plasma chemical vapor deposition using a reactant gas comprising a compound selected from the group consisting of organosilicon compounds, metal alkyl compounds, meal isopropoxide compounds, metal acetylacetonate compounds, metal halide compounds, and combinations thereof. Nanostructures of high aspect ratio and optionally with random dimensions in at least one dimension and preferably in three orthogonal dimensions can be prepared.
1. A method of making a nanostructure, comprising:
providing a substrate;
mixing a first gaseous species capable of depositing a layer onto the substrate when formed into a plasma, with a second gaseous species capable of etching the substrate when formed into a plasma, thereby forming a gaseous mixture;
forming the gaseous mixture into a plasma; and
exposing a surface of the substrate to the plasma, wherein the surface is etched and a layer is deposited on at least a portion of the etched surface simultaneously, thereby forming a nanostructure comprising nano-pillars or nano-columns having features of diverse height and aspect ratio.
2. A method of making a nanostructure according to claim 1 , wherein the substrate comprises a (co)polymeric material, an inorganic material, an alloy, a solid solution, or a combination thereof.
3. A method of making a nanostructure according to claim 2 , wherein the (co)polymeric material comprises a (co)polymer selected from poly(methyl methacrylate), poly(ethylene terephthalate), polycarbonate, cellulose, triacetate, polyamide, polyimide, a fluoropolymer, a polyolefin, a siloxane (co)polymer, a cyclic olefin (co)polymer, a polyurethane, and combinations thereof.
4. A method making a nanostructure according to claim 3 , wherein the (co)polymer is a polytetrafluoroethylene fluoropolymer and the surface of the substrate is substantially colorless after exposure to the plasma.
5. A method of making a nanostructure according to claim 1 , wherein the substrate comprises a transparent (co)polymer.
6. A method of making a nanostructure according to claim 1 , wherein the first gaseous species comprises a compound selected from the group consisting of organosilicon compounds, metal alkyl compounds, metal isopropoxide compounds, metal oxide compounds, metal acetylacetonate compounds, metal halide compounds, and combinations thereof.
7. A method of making a nanostructure according to claim 6 , wherein the organosilicon compounds comprise tetramethylsilane, trimethylsilane, hexamethyldisiloxane, tetraethylorthosilicate, a polyhedral oligomeric silsesquioxane, or a combination thereof.
8. A method of making a nanostructure according to claim 1 , wherein the second gaseous species comprises oxygen, a fluorocarbon, nitrogen trifluoride, sulfur hexafluoride, chlorine, hydrochloric acid, methane, or a combination thereof.
9. A method of making a nanostructure according to claim 8 , wherein the fluorocarbon is selected from tetrafluoromethane, perfluoropropane, and combinations thereof.
10. A method of making a nanostructure according to claim 1 , wherein the gaseous mixture further comprises argon.
11. A method of making a nanostructure according to claim 1 , wherein the nanostructure has a dimension of less than about 400 nanometers.
12. A method of making a nanostructure according to claim 11 , wherein the nanostructure has a dimension of less than about 40 nanometers.
13. An article comprising a nanostructure further comprising nano-pillars or nano-columns having features of diverse height and aspect ratio made from the method according to claim 1 .
14. An article according to claim 13 , having a Reflectance of less than 3% and a Haze Delta of less than 0.5%, optionally wherein the Reflectance is less than 2%.
15. An article according to claim 13 , wherein the etched surface has at least one nanostructure with an aspect ratio greater than 2:1, optionally wherein the etched surface has at least one nanostructure with an aspect ratio greater than 15:1.
16. An article according to claim 13 , wherein the deposited species is present over substantially the entire etched surface.
17. The article according to claim 16 , wherein the concentration of the deposited species varies continuously according to the depth from the exposed surface.
18. The article according to claim 13 , wherein the exposed surface comprises silanol groups.
19. The article according to claim 13 , further comprising a layer of pressure sensitive adhesive adhered to the exposed surface, optionally wherein the pressure sensitive adhesive and the substrate are UV stable.
20. The article according to claim 13 , wherein the exposed surface has a pattern that is random in at least one dimension, optionally wherein the exposed surface has a pattern that is random in three orthogonal dimensions.