Film-type solid polymer ionomer sensor and sensor cell

• US 7,404,882 B2
• Filed: 12/17/2003
• Issued: 07/29/2008
• Est. Priority Date: 11/19/1999
• Status: Expired due to Fees

• Current Assignee: PerkinElmer LAS, Inc. (Perkinelmer Incorporated)
• Original Assignee: PerkinElmer LAS, Inc. (Perkinelmer Incorporated)
• Inventors: Prohaska, Otto J., LaConti, Anthony B., Manoukian, Mourad, Giner, Jose D.
• Primary Examiner(s): Olsen; Kaj K
• Application Number:
  US10/738,858
• Publication Number:
  US 20040129565A1
• Time in Patent Office: 1,686 Days
• Field of Search: 204/424, 204/426, 204/431, 204/432
• US Class Current: 204/426
• CPC Class Codes: G01N 2030/125 pyrolising
• CPC Class Codes: G01N 2030/645 electrical conductivity detectors
• CPC Class Codes: G01N 27/4045 for gases other than oxygen
• CPC Class Codes: G01N 27/4074 for detection of gases other than oxygen

Abstract

A miniaturized gas sensor including film type electrodes, and a solid ionomer electrolyte, for the detection of toxic gases, i.e., carbon monoxide, and other oxidizable or reducible gases and vapors is described. The all-solid planar sensor cell has two or more film type electrodes arranged on a non-conductive planar surface of a supportive material. The electrodes are discrete and in intimate contact with the same solid polymer ionomer membrane. The sensor cell contains no liquid electrolyte and is operated in a potentiostatic or potentiodynamic mode. The unique feature of the sensor cell is that high sensitivity to a select gas or vapor is achieved by a novel three-phase contact area design for a sensing electrode which is easily accessible to the gas sample via small diffusion openings or holes that penetrate through the solid polymer ionomer membrane layer above the sensing electrode. A significant signal to background noise enhancement is achieved for these film type sensor cells by processes that increase the three-phase contact area.

Claims

1. A sensor cell, comprising:

a substrate having a surface for depositing electrodes thereon;

an electrode in contact with said surface;

an ionomer membrane in contact with said substrate and having a first location and a second location;

an opening in said membrane extending from said first location to said second location proximate to said electrode; and

wherein said opening is generally non-tortuous for defining a passage for a gas to pass freely from said first location to said second location and contact said electrode within said opening.

2. The sensor cell according to claim 1, further including a three-way contact point in said opening between said electrode, said gas, and said ionomer membrane.

3. The sensor cell according to claim 2, wherein said electrode is coated with a thin proton exchange film layer which acts to increase said three-way contact points.

4. The sensor cell according to claim 1, further comprising openings in said membrane proximate to said electrode which facilitate contact in said open three-phase area.

5. The sensor cell according to claim 4, wherein said openings in said membrane contain a particulate catalyst which electrically contacts said sensing electrode.

6. The sensor cell according to claim 1, wherein said electrode is a sensing electrode and further comprising a counter electrode and a reference in contact with said substrate.

7. The sensor cell according to claim 6, wherein said sensing, counter, and reference electrodes are formed by deposition on said membrane.

8. The sensor cell according to claim 6, wherein said sensing, counter, and reference electrodes are formed by deposition on said substrate.

9. The sensor cell apparatus according to claim 6, wherein said sensing, counter, and reference electrodes comprise a material selected from the group consisting of Pt, Au, C, platinized Pt, and platinized Au.

10. The sensor cell according to claim 1, wherein said ionomer membrane is comprised of dispersed metallic particles which act to increase said three-way contact points and to enhance signal response and stability.

11. The sensor cell according to claim 1, wherein said ionomer membrane is humidified by aqueous material.

12. The sensor cell according to claim 1, further comprising a microprocessor for real time data readout, data storage and retrieval, and remote data transmission.

13. The sensor cell according to claim 1 incorporated into a gas sensing instrument.

14. The sensor cell according to claim 1, comprising:

a plurality of electrode particles dispersed throughout said ionomer membrane;

wherein said opening defines a passage for a gas to pass from said first location to said second location and contact said electrode within said opening; and

wherein said plurality of electrode particles increase contact between the gas, electrode particles, and ionomer membrane.

15. The sensor cell according to claim 14, wherein said plurality of electrode particles are selected from the group consisting essentially of platinum, gold, RuO₂, metal oxides, and combinations thereof.

16. The sensor cell according to claim 14, wherein said opening provides a concentration gradient from said first location to said second location resulting in a generally steady state flux of gas.

17. A sensor cell, comprising:

a substrate having a surface for depositing electrodes thereon;

an electrode in contact with said surface of said substrate;

an ionomer membrane in contact with said substrate and having a first surface and a second surface;

an opening in said membrane extending from said first surface to said second surface in a location proximate to said electrode for defining a passage;

said opening is generally non-tortuous for defining a passage; and

a gas in said opening and simultaneously contacting said electrode and said ionomer membrane for providing a three-way contact between said gas, said electrode, and said ionomer membrane within said opening.