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; and   (c) applying a voltage to the electrochemical cell to deposit the complex on the anode.   
   
   
       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 copolymer. 
   
   
       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 7  wherein the first polymer comprises RNA. 
   
   
       11 . 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. 
   
   
       12 . A film comprising a substrate and, disposed on the substrate, (a) coagulant residue, and (b) a complex formed from carbon nanotubes and a first anionic polymer. 
   
   
       13 . A method according to  claim 12  wherein the first polymer comprises a nucleic acid molecule. 
   
   
       14 . A method according to  claim 12  wherein the first polymer comprises RNA. 
   
   
       15 . A film according to  claim 12  wherein there is further disposed on the substrate a second anionic polymer. 
   
   
       16 . A method according to  claim 15  wherein the second ionic polymer comprises a styrenic ionomer or an ionized ethylene/(meth)acrylic acid copolymer. 
   
   
       17 . A method according to  claim 15  wherein the first polymer comprises a nucleic acid molecule. 
   
   
       18 . A method according to  claim 15  wherein the first polymer comprises RNA. 
   
   
       19 . A cathode assembly for a field emission device comprising a film according to  claim 1 . 
   
   
       20 . A field emission device comprising a cathode assembly according to  claim 19 .