Method for making an electromagnetic shielding layer

1. A method for making an electromagnetic shielding layer, the method comprising the steps of:

(a) providing a surface;

(b) fabricating at least one carbon nanotube film;

(c) adhering a carbon nanotube film structure on the surface; and

(d) forming a conductive layer on the carbon nanotube film structure, thereby obtaining the electromagnetic shielding layer on the surface, wherein the carbon nanotube film structure is located between the surface and the conductive layer.

2. The method as claimed in claim 1 , wherein the step (b) comprises the substeps of:

(b1) providing a substrate with a super-aligned array of carbon nanotubes formed thereon; and

(b2) drawing the at least one carbon nanotube film from the super-aligned array of carbon nanotubes using a pulling tool.

3. The method as claimed in claim 2 , wherein step (b1) comprises:

(b11) providing a substantially flat and smooth substrate;

(b12) forming a catalyst layer on the substrate;

(b13) annealing the substrate with the catalyst at a temperature approximately ranging from 700° C. to 900° C. in air for about 30 to 90 minutes;

(b14) heating the substrate with the catalyst at a temperature approximately ranging from 500° C. to 740° C. in a furnace with a protective gas therein; and

(b15) supplying a carbon source gas into the furnace for about 5 to 30 minutes and growing the super-aligned array of the carbon nanotubes from the substrate.

4. The method as claimed in claim 3 , wherein the super-aligned array of carbon nanotubes has a height of about 200 to about 400 microns.

5. The method as claimed in claim 2 , wherein step (b2) comprises the substeps of:

(b21) selecting a plurality of carbon nanotube segments having predetermined widths and using the pulling tool to contact therewith;

(b22) drawing the carbon nanotube segments at a uniform speed along a direction perpendicular to the growing direction of the array of the carbon nanotubes to form the at least one carbon nanotube film.

6. The method as claimed in claim 5 , wherein the step (c) comprises the substeps of:

(c1) providing a frame;

(c2) laying the at least one carbon nanotube film on the frame and removing the excess film outside the frame, thereby forming the carbon nanotube film structure;

(c3) peeling the carbon nanotube film structure off the frame to achieve a self-supporting carbon nanotube film structure; and

(c4) placing the self-supporting carbon nanotube film structure on the surface.

7. The method as claimed in claim 5 , wherein the step (c) comprises the substeps of:

(c1) laying the at least one carbon nanotube film on the surface; and

(c2) removing the excess film, thereby forming the carbon nanotube film structure that is approximately the same shape and area as the surface.

8. The method as claimed in claim 2 , further comprising a step of locating a conductive layer on the surface before step (d).

9. The method as claimed in claim 1 , further comprising a step of treating the carbon nanotube film structure with an organic solvent after step (c).

10. The method as claimed in claim 9 , wherein the organic solvent is comprised of at least one solvent selected from the group consisting of ethanol, methanol, acetone, dichloroethane, chloroform, and combinations thereof.

11. The method as claimed in claim 9 , wherein the treating is done by either allowing organic solvent to soak the entire surface of the carbon nanotube film structure or by immerging the carbon nanotube film structure into a container having the organic solvent therein.

12. The method as claimed in claim 1 , wherein the conductive layer is formed by spraying or painting.

13. A method for making an electromagnetic shielding layer, the method comprising the steps of:

(a) providing an electronic element having a surface;

(b) fabricating at least one carbon nanotube film;

(c) adhering the at least one carbon nanotube film on the surface to obtain a carbon nanotube structure on the surface; and

(d) forming a conductive layer on the carbon nanotube film structure, thereby obtaining the electromagnetic shielding layer on the surface, wherein the carbon nanotube film structure is located between the surface and the conductive layer.

14. The method as claimed in claim 13 , wherein the step (b) comprises the substeps of:

(b1) providing a substrate with a super-aligned array of carbon nanotubes formed thereon;

(b2) drawing the at least one carbon nanotube film from the super-aligned array of carbon nanotubes.

15. The method as claimed in claim 14 , wherein step (b1) comprises:

(b11) providing a substantially flat and smooth substrate;

(b12) forming a catalyst layer on the substrate;

(b13) annealing the substrate with the catalyst at a temperature approximately ranging from 700° C. to 900° C. in air for about 30 to 90 minutes;

(b14) heating the substrate with the catalyst at a temperature approximately ranging from 500° C. to 740° C. in a furnace with a protective gas therein; and

(b15) supplying a carbon source gas into the furnace for about 5 to 30 minutes and growing the super-aligned array of the carbon nanotubes from the substrate.

16. The method as claimed in claim 15 , wherein the array of the carbon nanotubes has a height of about 200 to about 400 microns.

17. The method as claimed in claim 14 , wherein step (b2) comprises the substeps of:

(b21) selecting a plurality of carbon nanotube segments having predetermined widths and using a pulling tool to contact therewith; and

(b22) drawing the carbon nanotube segments at a uniform speed along a direction perpendicular to the growing direction of the super-aligned array of the carbon nanotubes to form the at least one carbon nanotube film.

18. The method as claimed in claim 17 , wherein the step (d) comprises the substeps of:

(d1) providing a conductive material which comprises metal or conductive polymer;

(d2) spraying or painting the conductive material on the surface of the carbon nanotube film structure; and

(d3) solidifying the conductive material in temperature ranging from 40° C. to 70° C., and forming the first conductive layer, thereby obtaining the electromagnetic shielding layer.