Method for the electrochemical deposition of carbon nanotubes

Abstract

This invention relates to the electrochemical deposition of carbon nanotubes (“CNTs”) on a substrate using an electrochemical cell. A dispersion of a complex of CNTs and an anionic polymer is neutralized and thereby caused to deposit on the anode plate of the cell.

1 . A method for the deposition of carbon nanotubes, comprising:
 (a) providing an electrochemical cell that comprises a cathode, an anode plate, a first electrically conducting pathway connecting the cathode to an electrical power supply, and a second electrically conducting pathway connecting the electrical power supply to the anode plate;   (b) providing as an aqueous electrolyte disposed between the cathode and the anode a dispersion of a complex formed from carbon nanotubes and a first anionic polymer;   (c) applying a voltage to the electrochemical cell to deposit the complex on the anode; and   (d) removing the anode plate from the electrochemical cell and firing the plate in air.   
     
     
         2 . A method according to  claim 1  wherein the aqueous electrolyte further comprises a coagulant. 
     
     
         3 . A method according to  claim 2  wherein coagulant residue is deposited on the anode together with the complex. 
     
     
         4 . A method according to  claim 1  wherein the first polymer comprises a nucleic acid molecule. 
     
     
         5 . A method according to  claim 1  wherein the first polymer comprises RNA. 
     
     
         6 . A method according to  claim 1  wherein the electrolyte further comprises a second anionic polymer. 
     
     
         7 . A method according to  claim 6  wherein the second ionic polymer comprises a styrenic ionomer or an ionized ethylene/(meth)acrylic acid 
     
     
         8 . A method according to  claim 6  wherein the complex, as deposited on the anode, is deposited in a matrix of the second anionic polymer. 
     
     
         9 . A method according to  claim 7  wherein the first polymer comprises a nucleic acid molecule. 
     
     
         10 . A method according to  claim 1  further comprising a step of removing the anode plate from the cell, and installing it in a field emission device. 
     
     
         11 . A method for the deposition of carbon nanotubes, comprising:
 (a) providing an electrochemical cell that comprises a cathode, an anode plate, a first electrically conducting pathway connecting the cathode to an electrical power supply, and a second electrically conducting pathway connecting the electrical power supply to the anode plate;   (b) providing an aqueous electrolyte disposed between the cathode and the anode, wherein the electrolyte comprises boric acid and/or a borate compound, and a dispersion of a complex formed from carbon nanotubes and a first anionic polymer; and   (c) applying a voltage to the electrochemical cell to deposit the complex on the anode.   
     
     
         12 . A method according to  claim 11  wherein boric acid and/or a borate compound is deposited on the anode together with the complex. 
     
     
         13 . A method according to  claim 11  wherein the aqueous electrolyte further comprises a coagulant. 
     
     
         14 . A method according to  claim 13  wherein coagulant residue is deposited on the anode together with the complex. 
     
     
         15 . A method according to  claim 11  wherein the first polymer comprises a nucleic acid molecule. 
     
     
         16 . A method according to  claim 11  wherein the first polymer comprises RNA. 
     
     
         17 . A method according to  claim 11  wherein the electrolyte further comprises a second anionic polymer. 
     
     
         18 . A method according to  claim 17  wherein the second ionic polymer comprises a styrenic ionomer or an ionized ethylene/(meth)acrylic acid copolymer. 
     
     
         19 . A method according to  claim 17  wherein the first polymer comprises a nucleic acid molecule. 
     
     
         20 . A method according to  claim 11  further comprising a step of removing the anode plate from the cell, and installing it in a field emission device. 
     
     
         21 . A film comprising a substrate and, disposed on the substrate, (a) boric acid and/or a borate compound, and (b) a complex formed from carbon nanotubes and a first anionic polymer. 
     
     
         22 - 28 . (canceled) 
     
     
         29 . A cathode assembly for a field emission device comprising a film according to  claim 21 . 
     
     
         30 . A field emission device comprising a cathode assembly according to  claim 29 . 
     
     
         31 - 35 . (canceled)