Method and apparatus for forming high surface area material films and membranes

Abstract

The present invention discloses a method and apparatus for producing high surface area material films and membranes on substrates. In one application, patterns of spikes or bristles are produced on wafers and transferred to films, such as conductive polymer or metal films, by using repetitive and inexpensive processes, such as electroplating and embossing. Such a technique provides low cost, high surface area materials and allows reuse of expensive patterned silicon. Membranes with high surface area are extremely valuable in fuel cells since the power density is generally proportional to the surface area and the patterns may be used to cast inexpensive fuel cell electrodes.

1 - 11 . (canceled)  
     
     
         12 . A method of producing a high surface area film comprising: 
 providing a wafer with a textured surface;    depositing a material onto the wafer to form a film; and    separating the film form the wafer, wherein a surface pattern of said texture surface is reproduced on said film.    
     
     
         13 . The method of  claim 12  wherein the textured surface comprises surface features having shapes selected from the group consisting of bristles, spikes, grass, steps, dimples and pores.  
     
     
         14 . The method of  claim 13  wherein the shapes are bristles.  
     
     
         15 . The method of  claim 12 , wherein the surface pattern of the textured surface is reproduced on the film within nanometer scale.  
     
     
         16 . The method of  claim 12  wherein said deposited material is selected from the group consisting of: a metal, a conductive polymer, and a biological material.  
     
     
         17 . The method of  claim 16  wherein said metal is selected from the group consisting of: ruthenium, rhodium, cobalt, iron, nickel, palladium, rhenium, osmium, platinum, and tungsten, and alloys thereof.  
     
     
         18 . The method of  claim 16  wherein said conductive polymer is Nafion®.  
     
     
         19 . The method of  claim 16  where said biological material is selected from the group consisting of: a lipid, a protein, an enzyme, an antibody, DNA, RNA, an amino acid, and a carbohydrate.  
     
     
         20 . The method of  claim 12 , further comprising preparing the surface of the wafer for film deposition by applying at least one preparation material onto the wafer.  
     
     
         21 . The method of  claim 20 , wherein said at least one preparation material is selected from the group consisting of: stainless steel, ruthenium, rhodium, cobalt, iron, nickel, palladium, rhenium, osmium, platinum, tungsten, and alloys thereof.  
     
     
         22 . The method of  claim 12 , wherein said step of depositing material comprises electroplating.  
     
     
         23 . The method of  claim 12 , wherein the film has a thickness of about 10 microns.  
     
     
         24 . A method of producing a high surface area film comprising: 
 providing a first wafer with a first textured surface;    providing a second wafer with a second textured surface;    embossing a film between the first and second wafers; and    removing the embossed film, wherein a surface pattern of the first and second wafer is reproduced on the film.    
     
     
         25 . The method of  claim 24 , wherein the first and second textured surfaces comprise surface features having shapes selected from the group consisting of bristles, spikes, grass, steps, dimples and pores.  
     
     
         26 . The method of  claim 25  wherein the shapes are bristles.  
     
     
         27 . The method of  claim 24 , wherein the step of embossing comprises: 
 preparing the film for embossing by inserting the film between the first and second wafers to create a wafer assembly;    securing the wafer assembly between metal plates to create a plate assembly; and    applying pressure to the plate.    
     
     
         28 . The method of  claim 27 , wherein the step of removing the embossed film comprises: 
 heating the plate assembly, wherein the film deforms; and    cooling the wafer assembly, wherein the first and second wafers fall away from the film.    
     
     
         29 . The method of  claim 28  wherein the step of cooling the wafer assembly is performed in liquid.  
     
     
         30 . A method of producing a high surface area film, comprising: 
 repeatedly forming surface features on a surface by first etching the surface with an inorganic halide plasma and then depositing a passivation layer onto said etched surface by means of an organic halide plasma;    depositing a catalytic material onto the passivation layer to form a film;    separating said catalytic material film from said passivation layer, wherein said catalytic material fim reproduces said surface features.    
     
     
         31 . The method of  claim 30  wherein the surface comprises surface features having shapes selected from the group consisting of bristles, spikes, grass, steps, dimples and pores.  
     
     
         32 . The method of  claim 31  wherein the shapes are bristles.  
     
     
         33 . The method of  claim 30  wherein said surface features comprise spikes having a diameter less than 1 micron.  
     
     
         34 . The method of  claim 30  wherein said deposited material is selected from the group consisting of: a metal, a conductive polymer, and a biological material.  
     
     
         35 . The method of  claim 34  wherein said metal is selected from the group consisting of: ruthenium, rhodium, cobalt, iron, nickel, palladium, rhenium, osmium, platinum, and tungsten, and alloys thereof.  
     
     
         36 . The method of  claim 34  wherein said conductive polymer is Nafion®.  
     
     
         37 . The method of  claim 34  wherein said biological material is selected from the group consisiting of: a lipid, a protein, an enzyme, an anibody, DNA, RNA, an amino acid, and a carybohydrate.