Porous film sensor

• US 8,643,463 B2
• Filed: 11/30/2009
• Issued: 02/04/2014
• Est. Priority Date: 11/30/2009
• Status: Expired due to Fees

• Current Assignee: Nanyang Polytechnic
• Original Assignee: Nanyang Polytechnic
• Inventors: Samah, Zuruzi Bin Abu
• Primary Examiner(s): LEE, KYUNG S
• Application Number:
  US13/512,392
• Publication Number:
  US 20120235781A1
• Time in Patent Office: 1,527 Days
• Field of Search: 338/13
• US Class Current: 338/13
• CPC Class Codes: B29D 7/01 Films or sheets
• CPC Class Codes: B29K 2105/04 cellular or porous
• CPC Class Codes: B29K 2105/162 Nanoparticles
• CPC Class Codes: C08J 5/18 Manufacture of films or sheets
• CPC Class Codes: G01L 1/20 by measuring variations in ohmic resistance of solid materials or of electrically-conductive fluids of piezo-resistive materials G01L1/18; by making use of electrokinetic cells, i.e. liquid-containing cells wherein an electrical potential is produced or varied upon the application of stress
• CPC Class Codes: Y10T 428/249921 Web or sheet containing structurally defined element or component

Abstract

A method of forming a film is described. The method begins by forming a mixture including a polymer and a plurality of unordered nanomaterial. The film is dried and a plurality of pores is formed within the film. A sensitive film transducer capable of detecting changes in pressure and applied force can be made using this method.

Claims

1. A method of forming a film, comprising:

forming a mixture including a polymer and a plurality of unordered nanomaterial;

forming a film using said mixture;

drying said film; and

forming a plurality of pores within said film.

2. The method according to claim 1, wherein said nanomaterial is nanowires.

3. The method according to claim 1, wherein said polymer is electrically insulating.

4. The method according to claim 1, wherein said nanomaterial is carbon nanotubes.

5. The method according to claim 4, wherein said carbon nanotubes are electrically conducting.

6. The method according to claim 5, wherein said carbon nanotubes are multi-walled carbon nanotubes.

7. The method according to claim 5, wherein said carbon nanotubes are single-walled carbon nanotubes.

8. The method according to claim 5, wherein said carbon nanotubes contain a mixture of single-walled and multi-walled carbon nanotubes.

9. The method of claim 5 wherein said pores separate said nanotubes in said film.

10. The method according to claim 5, wherein said mixture includes a isopropyl alcohol.

11. The method according to claim 10, wherein said step of forming said pores comprises:

evaporating said isoproplyl alcohol in said film to form said pores.

12. The method according to claim 10, wherein said film has a uniform thickness in the range of 100 nanometers to 1000 micrometers.

13. The method according to claim 12, wherein said film is 0.5 mm thick.

14. The method according to claim 12, wherein said step of drying said film comprises:

heating said film for a predetermined amount of time at a predetermined temperature.

15. The method according to claim 14, wherein said step of heating comprises:

heating said film for between about 20 to about 600 minutes.

16. The method according to claim 14, wherein said step of heating comprises:

heating said film for 120 minutes.

17. The method according to claim 14, wherein said step of heating said film comprises:

heating said film at a temperature between the range of about 25 to about 90 degrees Celsius.

18. The method according to claim 14, wherein said step of heating comprises:

heating said film at a temperature of substantially 60 degrees Celsius.

19. The method according to claim 14, wherein said step of heating comprises:

heating said film under a specified pressure.

20. The method according to claim 14, wherein said step of heating comprises:

heating said film under a pressure in a range from substantially 0.001 to substantially 1 atm.

21. The method according to claim 14, wherein said pores have sizes which range from substantially 100 nanometers to 500 micrometers.

22. The method according to claim 21, wherein said pores have uniform sizes.

23. The method according to claim 21, wherein said pores have a range of sizes.

24. The method according to claim 21, wherein a density of said pores in said film is between 5 to 75 percent by volume.

25. The method according to claim 21, wherein characteristics of said film changes significantly in pressure range of substantially 0.5 kPa to 100 kPa.