Processing of superhydrophobic, infrared transmissive, anti-reflective nanostructured surfaces

Abstract

Methods for producing nanostructured, hydrophobic, superhydrophobic, or hydrophilic, transmissive, anti-reflective surfaces are described. The method for providing a hydrophilic surface includes steps of providing a substrate that is transmissive at at least one wavelength in the infrared to ultraviolet range of the electromagnetic spectrum and comprises at least one surface including nanostructures of a size smaller than the at least one wavelength; and functionalizing the at least one surface with hydroxyl groups thereon. A hydrophobic or superhydrophobic surface can be provided by contacting the at least one surface with a hydrophobic fluoropolymer for a time sufficient to apply at least a monolayer of fluorine-containing material to the at least one surface. These methods provide devices having excellent transmittance and anti-reflectance properties and which are resistant to seawater.

What is claimed is: 
     
         1 . A method of forming a hydrophobic, anti-reflective, transmissive material, comprising:
 providing a substrate that is transmissive at at least one wavelength in the infrared to ultraviolet range of the electromagnetic spectrum and comprising at least one surface including nanostructures of a size smaller than the at least one wavelength;   functionalizing the at least one surface to provide hydroxyl groups thereon; and   contacting the at least one surface with a solution comprising a hydrophobic fluoropolymer for a sufficient time to apply at least a monolayer of a fluorine-containing material on the at least one surface.   
     
     
         2 . The method of  claim 1 , wherein the at least one hydrophobic fluoropolymer comprises fluorine proximate to or at a first end and a hydroxyl-reactive group on a second end. 
     
     
         3 . The method of  claim 1 , wherein the hydroxyl-reactive group contains a trichlorosilane group. 
     
     
         4 . The method of  claim 3 , wherein the at least one hydrophobic fluoropolymer is selected from the group consisting of, 1H,1H,2H,2H-perfluorooctyl trichlorosilane, 1H,1H,2H,2H-perfluorodecyl trichlorosilane, 1H,1H,2H,2H-perfluorodecyl acrylate, an amorphous polytetrafluoroethylene resin, and an alkyl or fluoroalkyl thiol. 
     
     
         5 . The method of  claim 1 , wherein the substrate is selected from the group consisting of, fused silica, quartz-containing materials, germanium-containing materials, alumina-containing materials, and other optical and non-optical glasses, crystals and ceramics. 
     
     
         6 . The method of  claim 1 , wherein the nanostructures occur in a non-random or periodic pattern. 
     
     
         7 . The method of  claim 1 , wherein the nano-structures occur in a random pattern. 
     
     
         8 . The method of  claim 1 , wherein the nano-structures have topological features selected from the group consisting of: jagged, pointed, cylindrical pillars, pointed cones, truncated cones, and a honeycomb pattern. 
     
     
         9 . The method of  claim 1 , wherein the nanostructures are patterned into the at least one surface of said substrate. 
     
     
         10 . The method of  claim 1 , wherein the contacting step is carried out for a period of 10 seconds to 3 minutes with a solution of the hydrophobic fluoropolymer. 
     
     
         11 . The method of  claim 1 , wherein the functionalizing step comprising plasma etching in an oxygen atmosphere. 
     
     
         12 . The method of  claim 1 , further comprising a step of curing at a temperature of at least 80° C. after the contacting step. 
     
     
         13 . The method of  claim 1 , wherein the at least one wavelength comprises a range of wavelengths in the infrared range of the electromagnetic spectrum. 
     
     
         14 . A method of forming an anti-reflective, transmissive, superhydrophilic material, comprising:
 providing a substrate that is transmissive at at least one wavelength in the infrared to ultraviolet range of the electromagnetic spectrum and comprising at least one surface including nanostructures of a size smaller than the at least one wavelength; and   functionalizing the at least one surface with hydroxyl groups thereon.   
     
     
         15 . The method of  claim 14 , wherein the substrate is selected from the group consisting of, fused silica, quartz-containing materials, germanium-containing materials, alumina-containing materials, and other optical and non-optical glasses, crystals and ceramics. 
     
     
         16 . The method of  claim 14 , wherein the at least one wavelength comprises a range of wavelengths in the infrared range of the electromagnetic spectrum. 
     
     
         17 . The method of  claim 14 , wherein the nanostructures are patterned into the at least one surface of said substrate and have topological features selected from the group consisting of: jagged, pointed, cylindrical pillars, pointed cones, truncated cones, and a honeycomb pattern. 
     
     
         18 . The method of  claim 14 , wherein the functionalizing step comprising plasma etching in an oxygen atmosphere. 
     
     
         19 . The method of  claim 14 , wherein the substrate is fused silica. 
     
     
         20 . The method of  14 , wherein the substrate is germanium.