Electroform, methods of making electroforms, and products made from electroforms

Abstract

In one embodiment, a method for making an electroform, comprises passivating a sub-master to form a passivation layer. The passivation comprises contacting at least a surface of the sub-master with a solution comprising an oxidizing agent and applying an anodic current to the sub-master. The surface of the sub-master can be plated with a metal to form a metal layer. The metal layer can be removed to form the electroform.

1 . A method for making an electroform, comprising: 
 forming a sub-master comprising a surface comprising microstructures with nanoscale resolution;    passivating the sub-master to form a passivation layer, wherein passivating comprises contacting at least a surface of the sub-master to be passivated with a solution comprising an oxidizing agent, and applying an anodic current to the sub-master, wherein the sub-master comprises nickel;    plating the surface of the sub-master with a metal to form a metal layer; and    removing the metal layer to form the electroform, wherein the electroform comprises the microstructures with nanoscale resolution.    
     
     
         2 . The method of  claim 1 , wherein the microstructures comprise a light-reflecting element selected from the group consisting of cube-corners, trihedral, hemispheres, prisms, ellipses, tetragonal, grooves, channels, microlenses, and combinations comprising at least one of the foregoing.  
     
     
         3 . The method of  claim 1 , wherein the sub-master has no visible damage as determined with a 40× microscope after the production of greater than or equal to about 50 electroforms.  
     
     
         4 . The method of  claim 3 , wherein the sub-master has no visible damage as determined with a 40× microscope after the production of greater than or equal to about 75 electroforms.  
     
     
         5 . The method of  claim 1 , wherein the solution is an aqueous solution having a pH of greater than or equal to about 10.  
     
     
         6 . The method of  claim 5 , wherein the pH is about 12 to about 14.  
     
     
         7 . The method of  claim 1 , wherein the solution further comprises a surfactant.  
     
     
         8 . The method of  claim 1 , wherein the anodic current is applied at about 1 ASF to about 40 ASF.  
     
     
         9 . The method of  claim 8 , wherein the anodic current is applied at about 5 ASF to about 25 ASF.  
     
     
         10 . The method of  claim 9 , wherein the anodic current is applied at about 5 ASF to about 10 ASF.  
     
     
         11 . The method of  claim 1 , wherein the sub-master comprises a nickel alloy.  
     
     
         12 . The method of  claim 11 , wherein the sub-master further comprises cobalt.  
     
     
         13 . The method of  claim 1 , wherein the solution further comprises an alkali metal hydroxide.  
     
     
         14 . The method of  claim 1 , wherein the passivation layer has a thickness of about 10 Å to about 500 Å.  
     
     
         15 . The method of  claim 14 , wherein the thickness is about 15 Å to about 60 Å.  
     
     
         16 . The method of  claim 1 , further comprising rinsing the passivation layer with water.  
     
     
         17 . The method of  claim 1 , wherein plating the surface further comprises: 
 disposing the surface in an electroforming solution comprising a sulfamate, and having a pH of less than or equal to about 6;    using the sub-master as a cathode; and    applying an electroforming current;    wherein the electroforming solution and/or an anode comprise the metal.    
     
     
         18 . The method of  claim 17 , wherein the metal comprises nickel and cobalt.  
     
     
         19 . The method of  claim 17 , wherein the electroforming current is about 2 ASF to about 100 ASF.  
     
     
         20 . An electroform produced by the method of  claim 2 .  
     
     
         21 . A film formed from the electroform of  claim 20 .  
     
     
         22 . A light management article comprising the film of  claim 21 .  
     
     
         23 . The article of  claim 22 , wherein the article is a backlight computer display.  
     
     
         24 . A method for making an electroform, comprising: 
 forming a sub-master comprising microstructures with nanoscale resolution;    contacting at least a surface of a sub-master with a solution comprising an alkaline metal hydroxide, wherein the surface comprises features to be replicated, and wherein the sub-master comprises nickel;    applying an anodic current of about 1 ASF to about 40 ASF to the sub-master to form a passivation layer having a thickness of about 10 Å to about 500 Å;    plating the surface of the sub-master with a metal to form a metal layer; and    removing the metal layer to form the electroform, wherein the electroform comprises the microstructures with nanoscale resolution.    
     
     
         25 . The method of  claim 24 , wherein plating the surface further comprises: 
 disposing the surface in an electroforming solution comprising a sulfamate, and having a pH of less than or equal to about 6;    using the sub-master as a cathode; and    applying a current;    wherein the electroforming solution and/or an anode comprise the metal.    
     
     
         26 . An electroform produced by the method of  claim 24 .  
     
     
         27 . A film formed from the electroform of  claim 26 .  
     
     
         28 . A light management article comprising the film of  claim 27 .  
     
     
         29 . The article of  claim 28 , wherein the article is a backlight computer display.