Method of making carbon nanotube composite materials

1. A method of making a composite material, comprising:

dissolving a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes in a solvent to make a solution; and

removing at least a portion of the solvent.

2. The method of claim 1 , wherein said solution is cast onto a surface prior to the step of removing at least a portion of the solvent to form a film.

3. The method of claim 1 , wherein said vinyl thermoplastic polymer is selected from the group consisting of poly(vinylidene fluoride), a polypropylene compound, a polyethylene compound, a polystyrene compound, a polyacrylate compound, a polyvinylchloride compound, a polyvinyl acetate compound, and copolymers thereof.

4. The method of claim 1 , wherein said un-functionalized carbon nanotubes are selected from the group consisting of un-functionalized single-wall nanotubes and un-functionalized multi-wall nanotubes.

5. The method of claim 1 , wherein said hydroxylated carbon nanotubes is selected from the group consisting of hydroxylated single-wall nanotubes and hydroxylated nanotubes.

6. The method of claim 1 , wherein said un-functionalized carbon nanotubes comprise a concentration of greater than 0 wt % and up to approximately 30 wt %.

7. The method of claim 1 , wherein said hydroxylated carbon nanotubes comprise a concentration of greater than 0 wt % and up to approximately 40 wt %.

8. The method of claim 1 , wherein said solvent is selected from the group consisting of dimethylformamide, dimethylacetamine, and methylpyrrolidone solvents.

9. The method of claim 8 , wherein said solvent is mixed with up to approximately 70 wt % of a second solvent selected from the group consisting of acetone, chloroform, chlorobenzenes, toluene, xylene, tetrahydrofuran, 2-methyltetrahydrofuran, ethyl acetate, and cyclopentyl methyl ether.

10. The method of claim 2 , wherein said film has a percolation threshold of less than approximately 0.5%.

11. The method of claim 2 , wherein said film has a conductivity of greater than 0.01 S/cm.

12. The method of claim 2 , wherein said solution is cast onto a surface by a method selected from the group consisting of spin, dip, brush, spray coating or drop casting.

13. The method of claim 1 , wherein said dissolving a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes in a solvent to make a solution is aid by a method selected from heating and agitation.

14. The method of claim 1 , wherein said un-functionalized carbon nanotubes have a concentration of greater than 0 wt % and less than approximately 4 wt %, and said hydroxylated carbon nanotubes have a concentration of greater than 0 wt % and less than approximately 10 wt % to produce a film with a conductivity of greater than 10 −5 S/cm.

15. The method of claim 1 , wherein an additive is added to the solvent.

16. The method of claim 14 , wherein said additive is selected from the group consisting of a surfactant, polystyrene sulfonate and polyethylene glycol.

17. The method of claim 15 , wherein said additive is added at a concentration of less than 10 wt %.

18. A method of making a composite material, comprising:

dissolving a polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes in a solvent to make a solution; and

removing at least a portion of the solvent;

wherein said un-functionalized carbon nanotubes comprise a concentration of greater than 0 wt % and up to approximately 30 wt %; and

wherein said hydroxylated carbon nanotubes comprise a concentration of greater than 0 wt % and up to approximately 40 wt %.

19. The method of claim 18 , wherein said un-functionalized carbon nanotubes are selected from the group consisting of un-functionalized single-wall nanotubes and un-functionalized multi-wall nanotubes.

20. The method of claim 18 , wherein said hydroxylated carbon nanotubes is selected from the group consisting of hydroxylated nanotubes and hydroxylated multi-wall nanotubes.