Carbon nanotube needle and method for making the same

Abstract

A carbon nanotube needle comprising: an end portion and a broken end portion, the broken end portion comprising a single carbon nanotube tip. A method for manufacturing a carbon nanotube needle, the method comprising the steps of: (a) providing a carbon nanotube film comprising of a plurality of commonly aligned carbon nanotubes, a first electrode, and a second electrode; (b) fixing the carbon nanotube film to the first electrode and the second electrode, the carbon nanotube film extending from the first electrode to the second electrode; (c) treating the carbon nanotube film with an organic solvent to form at least one carbon nanotube string; and (d) applying a voltage to the carbon nanotube string until the carbon nanotube string snaps.

1 . A carbon nanotube needle comprising:
 an end portion and a broken end portion, the broken end portion comprising a single carbon nanotube tip.   
     
     
         2 . The carbon nanotube needle as claimed in  claim 1 , wherein the broken end portion comprises a tapered-shaped structure formed by a plurality of carbon nanotubes. 
     
     
         3 . The carbon nanotube needle as claimed in  claim 1 , wherein a diameter of the carbon nanotube needle ranges from 1 to 20 microns, and a length thereof ranges from 0.01 to 1 millimeter. 
     
     
         4 . The carbon nanotube needle as claimed in  claim 1 , wherein the carbon nanotube needle is a carbon nanotube string. 
     
     
         5 . The carbon nanotube needle as claimed in  claim 4 , wherein the carbon nanotube needle comprises a plurality of substantially parallel carbon nanotubes. 
     
     
         6 . The carbon nanotube needle as claimed in  claim 5 , wherein the carbon nanotubes are joined end to end via van der Waals attractive force therebetween. 
     
     
         7 . The carbon nanotube needle as claimed in  claim 5 , wherein the carbon nanotubes in the end portion includes single-walled carbon nanotubes, double-walled carbon nanotubes, or multi-walled carbon nanotubes. 
     
     
         8 . The carbon nanotube needle as claimed in  claim 7 , wherein diameters of the single-walled carbon nanotubes, the double-walled carbon nanotubes, and the multi-walled carbon nanotubes is, respectively, in a range from 0.5 to 50 nanometers, 1 to 50 nanometers, and 1.5 to 50 nanometers. 
     
     
         9 . The carbon nanotube needle as claimed in  claim 1 , wherein the broken end portion has a diameter of less than 5 nanometers and approximately 2-3 walls. 
     
     
         10 . The carbon nanotube needle as claimed in  claim 1 , wherein the carbon nanotube that composes the tip extends 5 nanometers to 50 nanometers from adjacent carbon nanotubes. 
     
     
         11 . A method for manufacturing a carbon nanotube needle, the method comprising the steps of:
 (a) providing a carbon nanotube film comprising of a plurality of commonly aligned carbon nanotubes, a first electrode, and a second electrode;   (b) fixing the carbon nanotube film to the first electrode and the second electrode, the carbon nanotube film extending from the first electrode to the second electrode;   (c) treating the carbon nanotube film with an organic solvent to form at least one carbon nanotube string; and   (d) applying a voltage to the carbon nanotube string until the carbon nanotube string snaps.   
     
     
         12 . The method as claimed in  claim 11 , wherein in step (a), the carbon nanotube film provided is formed by the substeps of:
 (a 1 ) providing an array of carbon nanotubes; and   (a 2 ) pulling out a carbon nanotube film from the array of carbon nanotubes, by using a tool.   
     
     
         13 . The method as claimed in  claim 11 , wherein in step (c), the organic solvent is a volatile organic solvent and is selected from a group consisting of ethanol, methanol, acetone, dichloroethane, and chloroform. 
     
     
         14 . The method as claimed in  claim 11 , wherein step (c) further comprises the substeps of: putting the organic solvent onto the carbon nanotube film or putting the carbon nanotube film, the first electrode and the second electrode in the organic solvent. 
     
     
         15 . The method as claimed in  claim 11 , wherein a distance between the first electrode and the second electrode ranges from 50 micrometers to 2 millimeters. 
     
     
         16 . The method as claimed in  claim 11 , wherein step (d) further comprises the substep of:
 (d 1 ) placing the first electrode and the second electrode with the carbon nanotube string thereon in a chamber; and   wherein applying the voltage between two opposite ends of the carbon nanotube strings is done via the first electrode and the second electrode for a period of time to snap the carbon nanotube string, thereby acquiring at least one carbon nanotube needle with a break-end.   
     
     
         17 . The method as claimed in  claim 16 , wherein in step (d), wherein carbon nanotube string can reaches a temperature ranging approximately from 2000 to 2400 kelvins before snapping. 
     
     
         18 . A method for manufacturing a carbon nanotube needle, the method comprising the steps of:
 (a) providing a carbon nanotube string comprising of a plurality of carbon nanotubes, a first electrode, and a second electrode;   (b) fixing the two opposite sides of the carbon nanotube string to the first electrode and the second electrode; and   (c) applying a voltage between two opposite ends of the carbon nanotube string until the carbon nanotube string snaps, thereby obtaining at least one carbon nanotube needle;   wherein the at least one carbon nanotube needle has an end portion and a broken end portion; the broken end portion has a single tip carbon nanotube protruding from the broken end portion; and the carbon nanotubes are aligned along a same direction.   
     
     
         19 . The method as claimed in  claim 18 , wherein a plurality of the carbon nanotubes that comprise the carbon nanotube string are substantially parallel and joined end-to-end. 
     
     
         20 . The method as claimed in  claim 18 , wherein step (c) further comprises the substep of:
 (c 1 ) placing the carbon nanotube strings, the first electrode and the second electrode in a chamber; and   wherein applying the voltage between two opposite ends of the carbon nanotube strings is done via the first electrode and the second electrode for a period of time to snap the carbon nanotube string, thereby acquiring at least one carbon nanotube needle.