Method for producing carbon nanotubes, method for producing liquid dispersion thereof and optical product

Abstract

A method for producing dispersible carbon nanotubes of the invention comprises subjecting single-walled carbon nanotubes to UV treatment in the presence of ozone such that carboxyl groups are introduced into the single-walled carbon nanotubes and that the single-walled carbon nanotubes are fragmented. A carbon nanotubes obtained by the method has a good dispersibility.

1 . A method for producing dispersible carbon nanotubes, comprising
 subjecting single-walled carbon nanotubes to UV treatment in the presence of ozone such that carboxyl groups are introduced into the single-walled carbon nanotubes and that the single-walled carbon nanotubes are fragmented.   
     
     
         2 . The method for producing dispersible carbon nanotubes according to  claim 1 , wherein the UV treatment in the presence of ozone comprises applying ultraviolet light having at least two different wavelengths including a wavelength of 240 nm or less and a wavelength of 200 to 320 nm in the presence of oxygen so that the UV treatment is performed while the oxygen is converted into ozone. 
     
     
         3 . The method for producing dispersible carbon nanotubes according to  claim 1 , wherein the UV treatment uses an integrated quantity of light of 27 to 324 J/cm 2 . 
     
     
         4 . The method for producing dispersible carbon nanotubes according to  claim 1 , wherein the UV treatment is performed for a time period of 10 minutes to 120 minutes. 
     
     
         5 . A dispersible carbon nanotube produced by the method for producing dispersible carbon nanotubes according to  claim 1 . 
     
     
         6 . A method for producing a liquid dispersion of carbon nanotubes, comprising:
 subjecting single-walled carbon nanotubes to UV treatment in the presence of ozone such that carboxyl groups are introduced into the single-walled carbon nanotubes and that the single-walled carbon nanotubes are fragmented, in order to produce dispersible carbon nanotubes; and   then dispersing the dispersible carbon nanotubes in a solvent.   
     
     
         7 . The method for producing a liquid dispersion of carbon nanotubes according to  claim 6 , wherein the UV treatment in the presence of ozone comprises applying ultraviolet light having at least two different wavelengths including a wavelength of 240 nm or less and a wavelength of 200 to 320 nm in the presence of oxygen so that the UV treatment is performed while the oxygen is converted into ozone. 
     
     
         8 . The method for producing a liquid dispersion of carbon nanotubes according to  claim 6 , wherein the UV treatment uses an integrated quantity of light of 27 to 324 J/cm 2 . 
     
     
         9 . The method for producing a liquid dispersion of carbon nanotubes according to  claim 6 , wherein the UV treatment is performed for a time period of 10 minutes to 120 minutes. 
     
     
         10 . A liquid dispersion of carbon nanotube produced by the method for producing a liquid dispersion of carbon nanotubes according to  claim 6 . 
     
     
         11 . An optical product, comprising the dispersible carbon nanotubes according to  claim 5 . 
     
     
         12 . The optical product of  claim 11 , wherein the dispersible carbon nanotubes form a coating in a surface of the optical product. 
     
     
         13 . The optical product of  claim 12 , wherein the optical product with the coating of the dispersible carbon nanotube product has a surface with a surface resistivity of 1.0×10 10  Ω/square or less and has an absorptance of 3.0% or less.