Topologically structured polymer coating

Abstract

Sub-micron-structured (nanostructured) polymer film or coatings are made by coating a substrate with a mixture of materials. One of the materials is removed using a selective solvent, leaving pores or other nanostructure. The substrate may be grooved, providing a competing nanostructure. The coating may act as an antireflective coating, optical retarder, optical diffuser, or orientation layer.

What is claimed is: 
     
         1 . A polymer film or coating with oriented grooves, comprising a material which has elongated hollows, wherein the material is cross-linked and wherein the cross-linked material is a liquid crystal polymer, which has orientation. 
     
     
         2 . A polymer film or coating according to  claim 1 , wherein the hollows have arisen from the presence of another material which was then removed. 
     
     
         3 . A polymer film or coating according to  claim 1 , obtained by
 mixing at least two materials, of which at least one material is not cross-linkable and at least one other material is cross-linkable, wherein the cross-linkable material is liquid crystalline,   applying the mixture to a substrate comprising an orientation layer by using a coating method,   cross-linking said cross-linkable material while the cross-linkable material is maintained in an oriented state by the underlying orientation layer, and   removing a substantial portion of the non-cross-linked material.   
     
     
         4 . A polymer film or coating according to  claim 1 , wherein the orientation direction of the grooves is different in different parts of the film or coating. 
     
     
         5 . A polymer film or coating according to  claim 1 , wherein at least 99% of the hollows are smaller than 500 nm in at least one direction parallel to the film or coating plane. 
     
     
         6 . A polymer film or coating according to  claim 1 , wherein the average distance between adjacent hollows is less than 500 nm. 
     
     
         7 . A polymer film or coating according to  claim 1 , wherein the hollows are of continuously narrowing shape from top to bottom. 
     
     
         8 . A polymer film or coating according to  claim 1 , wherein the film or coating is over-coated with an additional layer. 
     
     
         9 . A polymer film or coating according to  claim 1 , wherein the film or coating is at least partly covered by a reflective layer that can act as an anisotropic diffusing reflector. 
     
     
         10 . A method of making a replica, comprising applying a material for the replica onto a polymer film or coating according to  claim 1 . 
     
     
         11 . A method according to  claim 10 , wherein the replica is made of a material selected from the group consisting of metals, pre-polymers, polymers, and dielectrics. 
     
     
         12 . Replica of a polymer film or coating, made according to the method of  claim 10 . 
     
     
         13 . An assembly comprising a layer of alignable molecules in contact with (A) a polymer film or coating with oriented grooves, comprising a material which has elongated hollows, wherein the material is cross-linked and wherein the cross-linked material is a liquid crystal polymer, which has orientation, or (B) a replica according to  claim 12 , the molecules being aligned thereby. 
     
     
         14 . A liquid crystal cell wherein the liquid crystal molecules can adopt one of at least two different stable alignments in contact with a wall of the cell, the cell wall comprising (A) a polymer film or coating with oriented grooves, comprising a material which has elongated hollows, wherein the material is cross-linked and wherein the cross-linked material is a liquid crystal polymer, which has orientation, or (B) a replica according to  claim 12 . 
     
     
         15 . An optical display device comprising (A) a polymer film or coating with oriented grooves, comprising a material which has elongated hollows, wherein the material is cross-linked and wherein the cross-linked material is a liquid crystal polymer, which has orientation, or (B) a replica according to  claim 12 . 
     
     
         16 . An element for protection against forgery and/or copying, which comprises (A) a polymer film or coating with oriented grooves, comprising a material which has elongated hollows, wherein the material is cross-linked and wherein the cross-linked material is a liquid crystal polymer, which has orientation, or (B) a replica according to  claim 12 .