Organic vapor sorbent protective device with thin-film indicator

• US 8,067,110 B2
• Filed: 09/11/2006
• Issued: 11/29/2011
• Est. Priority Date: 09/11/2006
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Mathers, James P., Rakow, Neal A., David, Moses M., Zhang, Jun-Ying, Wendland, Michael S., Paolucci, Dora M., Trend, John E., Poirier, Richard J.
• Primary Examiner(s): Bullock; In Suk
• Assistant Examiner(s): EOM, ROBERT J
• Application Number:
  US11/530,614
• Publication Number:
  US 20080063575A1
• Time in Patent Office: 1,905 Days
• Field of Search: 12820024-20718, 422 55- 60, 422/68.1, 422/82.05, 422 83- 88
• US Class Current: 429/119
• CPC Class Codes: G01N 21/783 for analysing gases
• CPC Class Codes: G01N 21/8422 Investigating thin films, e.g. matrix isolation method

Abstract

A sorbent media protective device includes an enclosure having a gas inlet, gas outlet and a thin-film multilayer indicator. The thin-film multilayer indicator is proximate sorbent media that can sorb a vapor of interest flowing from the gas inlet towards the gas outlet. The indicator includes a porous detection layer whose optical thickness changes in the presence of the vapor, located between a semireflective layer and a reflective layer permeable to the vapor. With equilibration at the applied vapor concentration between at least a portion of the media and the vapor, the vapor can pass through the reflective layer into the detection layer and change the detection layer optical thickness sufficiently to cause a visibly discernible change in the indicator appearance if viewed through the semireflective layer.

Claims

1. A protective device that comprises an enclosure including a gas inlet, gas outlet and a thin-film multilayer indicator, wherein:

A) the enclosure contains sorbent media that can sorb a vapor of interest flowing from the inlet towards the outlet;

B) the thin-film multilayer indicator comprises;

i) a porous detection layer whose optical thickness changes in the presence of the vapor, located between

ii) a semireflective layer viewable from outside the enclosure and

iii) a reflective layer that contains metal particles and that is permeable to the vapor; and

C) the reflective layer is in sufficient proximity to the media such that with equilibration at the applied vapor concentration between at least a portion of the media and the vapor, the vapor can pass from the media through the reflective layer and into the detection layer and change the detection layer optical thickness sufficiently to cause a visibly discernible change in the indicator appearance as viewed through the semireflective layer.

2. A device according to claim 1 wherein interference coloration is created or destroyed within the indicator when in the presence of the vapor.

3. A device according to claim 2 wherein the indicator provides a colorimetric change in appearance without requiring a powered light source, optical detector or spectral analyzer.

4. A device according to claim 1 wherein the indicator is illuminated using an external light source and evaluated using a photodetector.

5. A device according to claim 1 wherein a color change front advances with the flow of vapor through the media past the indicator.

6. A device according to claim 1 wherein the device comprises an air purifying respirator cartridge.

7. A device according to claim 1 comprising an array of indicators traversing the vapor flow path.

8. A device according to claim 1 wherein the indicator is flexible and sufficiently bendable without fracturing so that it can be made using one or more roll processing steps.

9. A device according to claim 1 wherein the indicator further comprises a substrate.

10. A device according to claim 9 wherein the enclosure comprises a transparent viewing port over the indicator.

11. A device according to claim 1 wherein the media comprises a finely-divided solid.

12. A device according to claim 11 wherein the media comprises carbon.

13. A device according to claim 1 wherein the detection layer has a range of pore sizes or a surface area selected to provide vapor sorption characteristics like those of the media.

14. A device according to claim 13 wherein the indicator has a visibly discernable coloration and the detection layer has pore diameters smaller than the indicator coloration peak wavelength.

15. A device according to claim 1 wherein the detection layer comprises porous silica, metal oxide, metal nitride, metal oxynitride or other inorganic material that can be formed into transparent and porous layers of appropriate thickness for producing color or a colorimetric change by optical interference.

16. A device according to claim 1 wherein the detection layer has been formed by plasma-activated chemical vapor deposition.

17. A device according to claim 1 wherein the detection layer comprises a polymer, copolymer or mixture thereof prepared or preparable from a hydrophobic (meth)acrylate, difunctional monomer, vinyl monomer, hydrocarbon monomer (olefin), silane monomer, fluorinated monomer, hydroxylated monomers, acrylamide, anhydride, aldehyde-functionalized monomer, amine- or amine salt-functionalized monomer, acid-functionalized monomer, epoxide-functionalized monomer or mixture or combination thereof.

18. A device according to claim 1 wherein the detection layer comprises a polymer having intrinsic microporosity.

19. A device according to claim 18 wherein the detection layer comprises a polymer of bis-catechol and a fluorinated arene.

20. A device according to claim 1 wherein the semireflective and reflective layers comprise a metal or metal oxide or a multilayer optical film.

21. A device according to claim 1 wherein the face of the semireflective layer adjacent the detection layer is flat to within about±

10 nm.

22. A device according to claim 1 further comprising a porous layer of sorbent-loaded composite between the reflective layer and a bed of sorbent media.

23. A respirator comprising a device according to claim 1.

24. The protective device of claim 1, wherein the metal particles are partially sintered.

25. The protective device of claim 24, wherein the metal particles comprise silver.

26. The protective device of claim 1, wherein the metal particles comprise a nanoparticle layer that is at least 2 or more nanoparticles thick.

27. The protective device of claim 1 being a filter cartridge.

28. The protective device of claim 1 being a respirator that includes one or more filter cartridges.

29. A process for making a protective device, which process comprises:

A) providing an enclosure including;

i) a space for containing sorbent media that will sorb a vapor of interest flowing through the enclosure; and

ii) a thin-film multilayer indicator comprising;

a) a porous detection layer whose optical thickness will change in the presence of the vapor, located between

b) a semireflective layer viewable from outside the enclosure and

c) a reflective layer that contains metal particles and that is permeable to the vapor;

B) placing the media in the enclosure in sufficient proximity to the reflective layer such that upon saturation of at least a portion of the media by the vapor, vapor can pass through the reflective layer into the detection layer and change the detection layer optical thickness sufficiently to cause a visibly discernible change in the indicator appearance as viewed through the semireflective layer; and

C) sealing the enclosure.

30. A process according to claim 29 wherein the device comprises an air purifying respirator cartridge.

31. A process according to claim 29 wherein the indicator is flexible and bendable without fracturing.

32. A process according to claim 29 wherein the enclosure comprises a transparent viewing port over the indicator.

33. A process according to claim 29 wherein the media comprises a finely-divided solid.

34. A process according to claim 33 wherein the media comprises carbon.

35. A process according to claim 29 wherein the detection layer comprises porous silica, metal oxide, metal nitride, metal oxynitride or other inorganic material that can be formed into transparent and porous layers of appropriate thickness for producing color or a colorimetric change by optical interference.

36. A process according to claim 29 further comprising forming the detection layer by plasma-activated chemical vapor deposition.

37. A process according to claim 29 wherein the detection layer comprises a polymer, copolymer or mixture thereof prepared or preparable from a hydrophobic (meth)acrylate, difunctional monomer, vinyl monomer, hydrocarbon monomer (olefin), silane monomer, fluorinated monomer, hydroxylated monomers, acrylamide, anhydride, aldehyde-functionalized monomer, amine- or amine salt-functionalized monomer, acid-functionalized monomer, epoxide-functionalized monomer or mixture or combination thereof.

38. A process according to claim 29 wherein the detection layer comprises a polymer having intrinsic microporosity.

39. A process according to claim 38 wherein the detection layer comprises a polymer of bis-catechol and a fluorinated arene.

40. A process according to claim 29 wherein the semireflective and reflective layers comprise a metal or metal oxide or a multilayer optical film.

41. A process according to claim 29 wherein the face of the semireflective layer adjacent the detection layer is flat to within about±

10 nm.

42. A process according to claim 29 further comprising placing a porous layer of sorbent-loaded composite between the reflective layer and a bed of sorbent media.

43. A process according to claim 29 further comprising attaching the enclosure to a respirator.

44. A method of making a filter cartridge, which method comprises:

A) providing an enclosure including;

i) a space for containing sorbent media that will sorb a vapor of interest flowing through the enclosure; and

ii) a thin-film multilayer indicator comprising;

a) a porous detection layer whose optical thickness will change in the presence

of the vapor, located between

b) a semireflective layer viewable from outside the enclosure and

c) a reflective layer that contains metal nanoparticles and that is permeable to the vapor;

B) placing the media in the enclosure in sufficient proximity to the reflective layer such that upon saturation of at least a portion of the media by the vapor, vapor can pass through the reflective layer into the detection layer and change the detection layer optical thickness sufficiently to cause a visibly discernible change in the indicator appearance as viewed through the semireflective layer; and

C) sealing the enclosure.