Covalently functionalized carbon nanostructures and methods for their separation
The present invention is directed to carbon nanostructures, e.g., carbon nanotubes, methods of covalently functionalizing carbon nanostructures, and methods of separating and isolating covalently functionalized carbon. In some embodiments, carbon nanotubes are reacted with alkylating agents to provide water soluble covalently functionalized carbon nanotubes. In other embodiments, carbon nanotubes are reacted with a thermally-responsive agent and exposed to light in order to separate carbon nanotubes of a specific chirality from a mixture of carbon nanotubes.
1. A method comprising:
a) introducing one or more defects onto one carbon nanotube type or chirality that is part of a mixture of carbon nanotubes by treating said mixture of carbon nanotubes with H 2 O 2 and HCl; and
b) reacting said carbon nanotube type or chirality comprising said one or more defects with an alkylating agent selected from the group consisting of dimethyl sulfate, diethyl sulfate, di-n-propyl sulfate, methyl-p-toluenesulfonate, ethyl methanesulfonate, n-propyl methanesulfonate, methyl bromide, ethyl bromide, n-propyl bromide, methyl iodide, ethyl iodide, n-propyl bromide, methyl iodine, and benzyl bromide,
wherein covalent functionalization of said carbon nanotube type or chirality propagates from said one or more defects to produce a covalently functionalized carbon nanotube type or chirality having alternating sections of functionalized and intact regions of said covalently functionalized carbon nanotube.
2. The method of claim 1 , wherein said reacting comprises combining said carbon nanotube comprising said one or more defects, said alkylating agent, liquid ammonia, and an alkali metal.
3. The method of claim 1 , wherein said one or more defects are introduced onto a metallic single-walled carbon nanotube.
4. The method of claim 1 , wherein said one or more defects are introduced onto a small-diameter single-walled carbon nanotube.
5. The method of claim 1 , wherein said alkylating agent is selected from the group consisting of dimethyl sulfate, diethyl sulfate, di-n-propyl sulfate, methyl-p-toluenesulfonate, ethyl methanesulfonate, and n-propyl methanesulfonate.
6. The method of claim 1 , wherein said alkylating agent is selected from the group consisting of methyl bromide, ethyl bromide, n-propyl bromide, methyl iodide, ethyl iodide, n-propyl bromide, methyl iodine, and benzyl bromide.