Claims:1. A method for preparation of a lubricant dispersed with carbon nanotubes (CNTs), the method comprising:
ball milling the CNTs to obtain CNTs with an optimum average length;
purifying the CNTs to remove impurities in the CNTs;
oxidizing surfaces of the purified CNTs by adding the purified CNTs to a solution comprising at least one oxidizing acid and refluxing the solution;
modifying the oxidized surfaces of the CNTs to obtain surface modified CNTs by adding the CNTs to a solution comprising at least one fatty acid; and
dispersing the surface modified CNTs in a lubricant to obtain the lubricant dispersed with CNTs, wherein the lubricant comprises about 90 to 99% base oil and about 1 to 10% additives.

2. The method as claimed in claim 1, wherein the ball milling is performed in a planetary ball mill comprising one or more tungsten carbide coated vials and one or more tungsten carbide coated balls for a time period of about 8 to 16 hours and the optimum average length of the CNTs is about 2 µm to about 3 µm.

3. The method as claimed in claim 1, wherein the purifying of the CNTs comprises:
heating the CNTs in air;
purifying the CNTs using hydrochloric acid solution; and
filtering out the CNTs from the hydrochloric acid solution.

4. The method as claimed in claim 3, wherein the heating of the CNTs is performed at a temperature of 600° C for a time period of about 1 hour.

5. The method as claimed in claim 3, wherein purifying the CNTs using hydrochloric acid solution comprises adding the CNTs to the hydrochloric acid solution and refluxing the hydrochloric acid solution at boil.

6. The method as claimed in claim 3, wherein filtering out the CNTs from the hydrochloric acid solution comprises:
diluting the hydrochloric acid solution with distilled water;
filtering the CNTs from the diluted hydrochloric acid solution;
washing the CNTs with distilled water until the CNTs are at a pH of about 7;
filtering the CNTs using a filter membrane system and a vacuum pump; and
drying the CNTs under vacuum.

7. The method as claimed in claim 1, wherein the solution comprising at least one oxidizing acid comprises hydrogen peroxide and sulphuric acid.

8. The method as claimed in claim 1, wherein the solution comprising at least one oxidizing acid comprises sulphuric acid and nitric acid.

9. The method as claimed in claim 1, wherein oxidizing surfaces of the purified CNTs comprises adding about 3 g of the CNTs to about 600 ml of the solution comprising at least one oxidizing acid and refluxing the solution at a temperature of about 120° C.

10. The method as claimed in claim 9 comprising filtering the CNTs from the solution comprising at least one oxidizing acid before modifying the oxidized surfaces of the CNTs.

11. The method as claimed in claim 1, wherein the oxidizing surfaces of the purified CNTs results in attachment of at least one hydrophilic functional group to the surfaces of the CNTs and wherein the at least one hydrophilic functional group is at least one of: a hydroxyl functional group and a carboxyl functional group.

12. The method as claimed in claim 1, wherein the at least one fatty acid comprises at least one of: stearic acid, lauric acid, and oleic acid.

13. The method as claimed in claim 1, wherein the CNTs are added to the solution comprising at least one fatty acid in a 1:4 weight ratio.

14. The method as claimed in claim 1, wherein adding the CNTs to the solution comprising at least one fatty acid comprises:
sonicating a CNT-fatty acid mixture in deionized water to form a suspension;
adding sulphuric acid to the suspension;
refluxing the solution at boil;
cooling the solution at ambient temperature;
filtering the CNTs from the solution;
washing the CNTs with distilled water until the CNTs are at a pH of about 7;
rinsing the CNTs with hexane;
filtering the CNTs; and
drying the CNTs.

15. The method as claimed in claim 14, wherein refluxing the solution is performed at a temperature of about 100° C for a time period in a range from about 2 hours to about 3 hours.

16. The method as claimed in claim 1, wherein dispersing the surface modified CNTs in the lubricant comprises:
adding the surface modified CNTs to the lubricant; and
sonicating a mixture of the lubricant and the surface modified CNTs.

17. The method as claimed in claim 16, wherein adding the surface modified CNTs to the lubricant comprises adding the surface modified CNTs to the lubricant in a range of about 0.05 weight % to 0.1 weight %.

18. The method as claimed in claim 16, wherein sonicating the mixture of the lubricant and the surface modified CNTs comprises:
sonicating the mixture of the lubricant and the surface modified CNTs under a pulse mode for a first time period; and
sonicating the mixture of the lubricant and the surface modified CNTs under a continuous mode for a second time period.

19. The method as claimed in claim 18, wherein sonicating the mixture of the lubricant and the surface modified CNTs under a pulse mode comprises sonicating, in an ultrasonic probe sonicator, for a time period of about 10 minutes at 50% amplitude for a 0.5 second pulse.

20. The method as claimed in claim 18, wherein sonicating the mixture of the lubricant and the surface modified CNTs under a continuous mode comprises sonicating, in an ultrasonic probe sonicator, for a time period of about 30 minutes at 50% amplitude.

21. A lubricant dispersed with surface modified carbon nanotubes (CNTs) comprising:
a lubricant comprising about 90% to 99% base oil and about 1% to 10% additives; and
surface modified CNTs from about 0.05 weight % to 0.1 weight % dispersed in the lubricant, wherein the surface modified CNTs comprise CNTs having a long chained functional group attached to surfaces of the CNTs.
, Description:As Attached