Anti-Reflective Coatings Comprising Ordered Layers of Nanowires and Methods of Making and Using the Same

Abstract

The present invention is directed to anti-reflective coatings comprising ordered layers of nanowires, methods to prepare the coatings, and products prepared by the methods.

1 - 24 . (canceled) 
     
     
         25 . A process for preparing an anti-reflective multi-layer nanowire coating on at least a portion of a surface of a substrate, the process comprising: disposing on the surface a first laminar layer of nanowires, wherein the first laminar layer has a refractive index about 60% to about 100% of a refractive index of the substrate; affixing the first laminar layer of nanowires to the surface; disposing a second laminar layer of nanowires onto the first laminar layer of nanowires; affixing the second laminar layer of nanowires to the first laminar layer of nanowires; disposing at least a third laminar layer of nanowires onto the second laminar layer of nanowires; and affixing the third laminar layer of nanowires to the second laminar layer of nanowires; wherein the second laminar layer of nanowires has a refractive index less than the refractive index of the first laminar layer of nanowires, and wherein the third laminar layer of nanowires has a refractive index less than the refractive index of the second laminar layer of nanowires. 
     
     
         26 . The process of  claim 25 , further comprising: aligning the nanowires within the first laminar layer to orient the nanowires substantially parallel to one another; aligning the nanowires within the second laminar layer to orient the nanowires within the second laminar layer substantially parallel to one another, wherein the nanowires within the second laminar layer are not parallel to the nanowires within the first laminar layer; and aligning the nanowires within the third laminar layer to orient the nanowires within the third laminar layer substantially parallel to one another, wherein the nanowires within the third laminar layer are not parallel to the nanowires within the second laminar layer. 
     
     
         27 . The process of  claim 26 , wherein the aligning comprises at least one of: applying a mechanical force to the nanowires, applying a magnetic field to the nanowires, applying an electric field to the nanowires, applying a fluid gradient to the nanowires, and combinations thereof. 
     
     
         28 . The process of  claim 25 , wherein the affixing comprises at least one of: sintering, covalently bonding, cross-linking, melting, encapsulating in a polymeric or molecular matrix, and combinations thereof. 
     
     
         29 . The process of  claim 25 , further comprising disposing a fourth laminar layer of nanowires onto the third laminar layer of nanowires, wherein the fourth laminar layer of nanowires has a refractive index less than the refractive index of the third laminar layer of nanowires. 
     
     
         30 . The process of  claim 25 , further comprising aligning the nanowires within the fourth laminar layer to orient the nanowires within the fourth laminar layer substantially parallel to one another, wherein the nanowires within the fourth laminar layer are not parallel to the nanowires within the third laminar layer 
     
     
         31 . A product prepared by the process of  claim 25 . 
     
     
         32 . The product of  claim 31 , wherein the product is chosen from: an antenna, a mirror, a window, a watch glass, a dome, a cone, a lens, and combinations thereof. 
     
     
         33 - 34 . (canceled) 
     
     
         35 . A composition, comprising: a substrate including a surface; and an anti-reflective multi-layer coating positioned on at least a portion of the surface, the coating comprising three or more laminar layers, each layer comprising a matrix incorporating a different degree of porosity compared to the other layers in the coating, wherein a bottom layer of the coating is affixed to the surface, wherein the bottom layer has a refractive index of about 60% to about 100% of a refractive index of the substrate, wherein a top-most layer of the coating has a refractive index of about 1% to about 40% of the refractive index of the substrate, and wherein the refractive index of the three or more laminar layers decreases by about 10% or more per layer from the bottom layer of the coating to the top-most layer of the coating. 
     
     
         36 . The composition of  claim 35 , wherein a portion of the surface having the anti-reflective multi-layer coating thereon reflects about 50% or less of an electromagnetic radiation having at least one wavelength of about 180 nm to about 30 μix compared to an uncoated portion of the surface. 
     
     
         37 . The composition of  claim 35 , wherein the anti-reflective multi-layer coating comprises a multitude of pores having a diameter of about 1 nm to about 100 nm. 
     
     
         38 . The composition of  claim 35 , wherein the matrix comprises one or more polymers selected from: a polystyrene, a polysiloxane, a polyacrylate, a polyvinylpyrrolidone, a polycarbonate, a polyalkyleneglycol, a (styrene-ethylene-butylene) tri-block copolymer grafted with maleic anhydride, and combinations thereof. 
     
     
         39 . A process for preparing an anti-reflective multi-layer coating on at least a portion of a surface of a substrate, the process comprising: printing on the surface a first laminar layer comprising a first polymer and an optional second polymer; printing on the first laminar layer a second laminar layer comprising the first polymer and the second polymer, wherein the second laminar layer is substantially free from solvent, and the second polymer is present in the second layer in a higher concentration than the first layer; printing on the second laminar layer a third laminar layer comprising the first polymer and the second polymer, wherein the third laminar layer is substantially free from solvent, and the second polymer is present in the third layer in a higher concentration than the second layer; optionally exposing the first laminar layer to conditions suitable for removing the second polymer from the first laminar layer while retaining the first polymer within the first laminar layer; exposing the second laminar layer to conditions suitable for removing the second polymer from the second laminar layer while retaining the first polymer within the second laminar layer; and exposing the third laminar layer to conditions suitable for removing the second polymer from the third laminar layer while retaining the first polymer within the third laminar layer to provide an anti-reflective multi-layer coating having a refractive index gradient. 
     
     
         40 . The process of  claim 39 , wherein the optionally exposing is performed simultaneous with the exposing the second laminar layer and the exposing the third laminar layer. 
     
     
         41 . The process of  claim 39 , wherein the optionally exposing is performed prior to the printing on the first laminar layer a second laminar layer; and the exposing the second laminar layer is performed prior to printing on the second laminar layer a third laminar layer. 
     
     
         42 . The process of  claim 39 , wherein the exposing comprises a process selected from: heating the laminar layer, irradiating the laminar layer with electromagnetic radiation, irradiating the laminar layer with an electron beam, exposing to a selective solvent, pyrrolizing, exposing the laminar layer to a plasma, and combinations thereof. 
     
     
         43 . The process of  claim 39 , wherein the printing comprises: coating an elastomeric stamp with a composition comprising a pre-determined amount of the first polymer, the optional second polymer, and a solvent to provide a coated stamp; phase separating the polymers on the coated stamp; removing the solvent from the composition; and contacting the coated stamp with the surface under conditions sufficient to transfer the composition from the coated stamp to the surface.