Carbon nanotube separation by reversible gelation

1. A composition comprising:

a gelling agent including an organic amine having two or more functional groups; and

a solution having a first type of carbon nanotubes with an affinity or miscibility for inclusion in a gel such that the gelling agent non-covalently cross-links with at least a portion of the first type of nanotubes to form the gel, and a second type of carbon nanotubes with a different affinity or miscibility from the first type of carbon nanotubes such that the first type of carbon nanotubes and the second type of carbon nanotubes are separated through a compaction of the gel causing the second type of carbon nanotubes to be removed as a liquid.

2. The composition of claim 1 , wherein the first type of carbon nanotubes comprise metallic carbon nanotubes and the second type of carbon nanotubes include semiconducting carbon nanotubes.

3. The composition of claim 1 , wherein the organic amine comprises a bi-functional amine.

4. The composition of claim 1 , wherein the organic amine comprises a poly-functional amine.

5. The composition of claim 1 , wherein the organic amine comprises at least one of diaminobutane, polyoxyethyl bis(amine), or polyethylene amine.

6. The composition of claim 1 , wherein the composition further comprises a surfactant.

7. The composition of claim 6 , wherein the surfactant comprises sodium dodecyl sulfate.

8. A composition comprising:

a gel including an amine; and

a solution having a first type of carbon nanotubes with an affinity or miscibility for inclusion in the gel such that the amine of the gel non-covalently cross-links with at least a Portion of the first type of nanotubes to form an expanded gel, and a second type of carbon nanotubes with a different affinity or miscibility from the first type of carbon nanotubes such that the first type of carbon nanotubes and the second type of carbon nanotubes are separated through a compaction of the expanded gel causing the second type of carbon nanotubes to be removed as a liquid.

9. The composition of claim 8 , wherein the first type of carbon nanotubes comprise metallic carbon nanotubes and the second type of carbon nanotubes include semiconducting carbon nanotubes.

10. The composition of claim 8 , wherein the amine comprises at least one of a bi-functional amine or a poly-functional amine.

11. The composition of claim 8 , wherein the gel comprises a cross-linked polyamine.

12. The composition of claim 8 , wherein the gel comprises a solvent.

13. The composition of claim 12 , wherein the solvent comprises n-methylpyrrolidone.

14. A composition comprising:

an inorganic amine based gel; and

a solution having a first type of carbon nanotubes with an affinity or miscibility for inclusion in the gel such that an inorganic amine of the inorganic amine based gel non-covalently cross-links with at least a portion of the first type of nanotubes to form an expanded gel, and a second type of carbon nanotubes with a different affinity or miscibility from the first type of carbon nanotubes such that the first type of carbon nanotubes and the second type of carbon nanotubes are separated through a compaction of the expanded gel causing the second type of carbon nanotubes to be removed as a liquid.

15. The composition of claim 14 , wherein the first type of carbon nanotubes comprise metallic carbon nanotubes and the second type of carbon nanotubes include semiconducting carbon nanotubes.

16. The composition of claim 14 , wherein the amine comprises at least one of a bi-functional amine or a poly-functional amine.

17. The composition of claim 14 , wherein the gel comprises a cross-linked polyamine.

18. The composition of claim 14 , wherein the gel comprises a solvent.