Adhesion-promoting surface

Abstract

An article is provided, the article including a substrate having a surface, a nano-structure array formed on the substrate, the nano-structure array including a plurality of nano-structures extending from the surface of the substrate, and a cover layer formed on and around the nano-structures to anchor the cover layer to the substrate.

What is claimed is: 
     
         1 . An article, comprising:
 a substrate having a surface;   a nano-structure array formed on the substrate, the nano-structure array including a plurality of nano-structures extending from the surface of the substrate; and   a cover layer formed on and around the nano-structures to anchor the cover layer to the substrate.   
     
     
         2 . The article of  claim 1 , wherein the nano-structures include stem portions extending from the surface of the substrate and having a first thickness, and include cap portions extending from the stem portions and having a second thickness greater than the first thickness to mechanically anchor the cover layer to the substrate. 
     
     
         3 . The article of  claim 1 , wherein the substrate includes a first surface region with a first set of nano-structures extending in a first direction and a second surface region with a second set of nano-structures extending in a second direction intersecting with the first direction. 
     
     
         4 . The article of  claim 3 , wherein the first set of nano-structures are substantially orthogonal to the first surface region and the second set of nano-structures are substantially orthogonal to the second surface region. 
     
     
         5 . The article of  claim 1 , wherein the cover layer is formed of a flowable material that substantially envelops the nano-structures before being solidified to secure the cover layer to the substrate. 
     
     
         6 . A method of adhering a cover layer to a substrate, the method comprising:
 forming an array of nano-structures on a substrate;   applying a flowable material to the substrate, the flowable material substantially enveloping the nano-structures on the substrate; and   solidifying the flowable material to form a cover layer on the substrate, the cover layer being anchored to the substrate via the nano-structures.   
     
     
         7 . The method of  claim 6 , wherein forming an array of nano-structures includes:
 forming a template on the substrate, the template defining nano-pores having a first width;   partially filling the nano-pores to define stem portions of a first thickness corresponding to the first width;   re-shaping the nano-pores to define re-shaped nano-pore sections having a second width greater than the first width;   at least partially filling the re-shaped nano-pore sections to define cap portions of a second thickness corresponding to the second width; and   removing the template.   
     
     
         8 . The method of  claim 7 , wherein partially filling the nano-pores includes:
 forming a layer of a first oxidizable material; and   anodizing the layer of first oxidizable material to grow oxide from the first oxidizable material into the nano-pores.   
     
     
         9 . The method of  claim 8 , wherein at least partially filling the re-shaped nano-pore sections includes further anodizing the first oxidizable material to grow oxide into the re-shaped nano-pore sections. 
     
     
         10 . The method of  claim 9 , wherein forming a template includes:
 forming a layer of a second oxidizable material; and   anodizing the layer of second oxidizable material to define the nano-pores.   
     
     
         11 . The method of  claim 6 , wherein forming an array of nano-structures on a substrate includes forming a first set of orthogonal nano-structures on a first surface region and forming a second set of orthogonal nano-structures on a second surface region, the first region intersecting the second region such that the cover layer is locked in place upon solidifying the flowable material to form the cover layer. 
     
     
         12 . A method of adhering a cover layer to a substrate, the method comprising:
 depositing a first oxidizable material onto the substrate;   depositing a second oxidizable material onto the first oxidizable material;   anodizing the second oxidizable material to form a porous oxide having nano-pores in the porous oxide;   anodizing the first oxidizable material so as grow an oxide of the first oxidizable material into the nano-pores;   removing the porous oxide, thereby yielding an array of spaced nano-structures extending from the substrate;   applying a flowable material to the substrate, the flowable material flowing between the spaced nano-structures; and   solidifying the flowable material to form a cover layer on the substrate, the cover layer being anchored to the substrate via the nano-structures.   
     
     
         13 . The method of  claim 12 , wherein anodizing the first oxidizable material includes growing a first set of nano-structures on a first surface region of the substrate and growing a second set of nano-structures on a second surface region of the substrate, the first region intersecting the second region such that the cover layer is locked in place upon solidifying the flowable material to form the cover layer. 
     
     
         14 . The method of  claim 12 , wherein anodizing the first oxidizable material includes growing an oxide into the nano-pores to define stem portions having a first width, broadening cap-forming sections of the nano-pores, and growing oxide into the nano-pores to define cap portions having a second width greater than the first width, thereby defining nano-structures having cap portions that anchor the cover layer to the substrate upon solidifying the flowable material to form the cover layer. 
     
     
         15 . The method of  claim 12 , wherein solidifying the flowable material includes chemically bonding the cover layer to the nano-structures.