Functionalized Boron Nitride Nanotubes

Abstract

A plasma treatment has been used to modify the surface of BNNTs. In one example, the surface of the BNNT has been modified using ammonia plasma to include amine functional groups. Amine functionalization allows BNNTs to be soluble in chloroform, which had not been possible previously. Further functionalization of amine-functionalized BNNTs with thiol-terminated organic molecules has also been demonstrated. Gold nanoparticles have been self-assembled at the surface of both amine- and thiol-functionalized boron nitride Nanotubes (BNNTs) in solution. This approach constitutes a basis for the preparation of highly functionalized BNNTs and for their utilization as nanoscale templates for assembly and integration with other nanoscale materials.

1 . A structure, comprising:
 a boron nitride nanotube; and   a first organic molecule attached to a surface of the boron nitride nanotube.   
     
     
         2 . The structure of  claim 1  wherein the first organic molecule is selected from the group consisting of amines, carboxyls, imines, hydroxyls and nitrites. 
     
     
         3 . The structure of  claim 1  wherein the first organic molecule is an amine. 
     
     
         4 . The structure of  claim 1 , further comprising a second organic molecule coupled to the first organic molecule. 
     
     
         5 . The structure of  claim 4  wherein the second organic molecule comprises 3-bromopropanoylchloride. 
     
     
         6 . The structure of  claim 4  wherein the second organic molecule comprises a thiol. 
     
     
         7 . The structure of  claim 6  wherein the thiol comprises 3-mercaptopropionic acid. 
     
     
         8 . The structure of  claim 4 , further comprising a nanoparticle attached to the second organic molecule. 
     
     
         9 . The structure of  claim 8  wherein the nanoparticle is selected from the group consisting of Au, Ag, Pd, CdS, CdSe, Pt, Co, CoPt, Cu, and ZnS. 
     
     
         10 . The structure of  claim 9  wherein the gold nanoparticle comprises a gold nanoparticle stabilized with 4-dimethylaminopyridine. 
     
     
         11 . A boron nitride nanotube functionalized with a self-assembly of nanoparticles. 
     
     
         12 . The nanotube of  claim 11  wherein the self-assembly of nanoparticles comprises approximately a monolayer of nanoparticles. 
     
     
         13 . A method of modifying boron nitride nanotubes, comprising the steps of:
 a) providing boron nitride nanotubes;   b) introducing the boron nitride nanotubes into a chamber equipped with a plasma generator; and   c) exposing the boron nitride nanotubes to an ammonia plasma in the chamber, thus forming amine-functionalized boron nitride nanotubes.   
     
     
         14 . The method of  claim 13  wherein the ammonia plasma is produced in the chamber by employing a method comprising the steps of:
 i) pumping the chamber to a pressure less than or approximately equal to 0.3 Pa;   ii) flowing ammonia gas into the chamber;   iii) applying a bias voltage of −100V to the boron nitride nanotubes; and   iv) applying power to the plasma generator.   
     
     
         15 . The method of  claim 14  wherein flowing the ammonia gas comprises flowing the gas at a rate of approximately 10 sccm under a pressure of approximately 400 Pa. 
     
     
         16 . The method of  claim 14  wherein applying a bias voltage comprises applying a bias voltage of between about −50 V and −200V. 
     
     
         17 . The method of  claim 14  wherein applying a bias voltage comprises applying a bias voltage of about −100V. 
     
     
         18 . The method of  claim 14  wherein applying power comprises applying power of between about 100 W and 500 W. (approximately 200 W). 
     
     
         19 . The method of  claim 14  wherein applying power comprises applying power of about 200 W. 
     
     
         20 . The method of  claim 13 , further comprising the step of:
 d) combining the amine-functionalized boron nitride nanotubes with a liquid 3-bromopropanoylchloride reagent to form a mixture.   
     
     
         21 . The method of  claim 13 , further comprising the steps of:
 d) combining the amine-functionalized boron nitride nanotubes with de-ionized water to form a suspension;   e) adding a solution of 3-mercaptopropionic acid, N-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride and 4-dimethylaminopyridine in de-ionized water to the suspension to form a mixture;   
     
     
         22 . A method of modifying boron nitride nanotubes, comprising the steps of:
 a) providing boron nitride nanotubes;   b) introducing the boron nitride nanotubes into a chamber equipped with a plasma generator; and   c) exposing the boron nitride nanotubes to a plasma, thus forming functionalized boron nitride nanotubes.   
     
     
         23 . The method of  claim 22  wherein the plasma is produced in the chamber by employing a method comprising the steps of:
 i) pumping the chamber to a pressure less than or approximately equal to 0.3 Pa;   ii) flowing a gas or gas mixture into the chamber;   iii) applying a negative bias voltage to the boron nitride nanotubes; and   iv) applying power to the plasma generator.   
     
     
         24 . The method of  claim 23  wherein the gas or gas mixture is selected from the group consisting of ammonia, H 2 +N 2 , CH 4 +O 2 , CH 4 +N 2 , H 2 O, and N 2 +O 2 . 
     
     
         25 . The method of  claim 22 , further comprising the steps of:
 d) combining the functionalized boron nitride nanotubes with a liquid 3-bromopropanoylchloride reagent to form a mixture.   
     
     
         26 . The method of  claim 22 , further comprising the steps of:
 d) combining the functionalized boron nitride nanotubes with de-ionized water to form a suspension;   e) adding a solution of 3-mercaptopropionic acid, N-(3-dimethylaminopropyl)-N-ethylcarbodiimide hydrochloride and 4-dimethylaminopyridine in de-ionized water to the suspension to form a mixture;   
     
     
         27 . The method of  claim 24  wherein either the ammonia gas or the H 2 +N 2  gas mixture forms amine-functionalized boron nitride nanotubes. 
     
     
         28 . The method of  claim 24  wherein the CH 4 +O 2  gas mixture forms carboxyl-functionalized boron nitride nanotubes. 
     
     
         29 . The method of  claim 24  wherein the CH 4 +N 2  gas mixture forms imine-functionalized boron nitride nanotubes. 
     
     
         30 . The method of  claim 24  wherein the H 2 O gas forms hydroxyl-functionalized boron nitride nanotubes. 
     
     
         31 . The method of  claim 24  wherein the N 2 +O 2  gas mixture forms nitrile-functionalized boron nitride nanotubes. 
     
     
         32 . The method of  claim 22 , further comprising combining the nanotubes with nanoparticle after step c. 
     
     
         33 . A stable solution, comprising functionalized boron nitride nanotubes dispersed in an organic solvent.