Electrochemical sensor with dry ionomer membrane and methodfor making the same

• US 7,422,646 B2
• Filed: 10/22/2001
• Issued: 09/09/2008
• Est. Priority Date: 10/22/2001
• Status: Expired due to Fees

• Current Assignee: PerkinElmer LAS, Inc. (Perkinelmer Incorporated)
• Original Assignee: PerkinElmer LAS, Inc. (Perkinelmer Incorporated)
• Inventors: Dalmia, Avinash, Prohaska, Otto J.
• Primary Examiner(s): Olsen; Kaj K
• Application Number:
  US10/029,659
• Publication Number:
  US 20030085125A1
• Time in Patent Office: 2,514 Days
• Field of Search: 204421-429, 204/415, 156/60
• US Class Current: 156/60
• CPC Class Codes: G01N 27/4045 for gases other than oxygen
• CPC Class Codes: G01N 27/4071 using sensor elements of laminated structure
• CPC Class Codes: G01N 27/4074 for detection of gases other than oxygen
• CPC Class Codes: Y10T 156/10 Methods of surface bonding and/or assembly therefor
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

A miniaturized gas sensor comprised of film type electrodes, on a non-conductive supportive substrate, and in contact with a dry ionomer electrolyte, for detection of toxic gases, i.e., carbon monoxide, and other oxidizable or reducible gases and vapors and method of making same 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 substrate. Manufacturing the electrochemical sensor with dry ionomer prevents electrode flooding and allows for improved response time upon assembly. The sensor cell contains no liquid electrolyte and is operated in a constant-voltage, potentiostatic or potentiodynamic mode. A high sensitivity to a select gas or vapor is achieved by a three-phase contact area design for a sensing electrode, which provides contact with the solid ionomer electrolyte, as well as the gas sample via diffusion openings or holes that penetrate through the supportive substrate.

Claims

1. A method of making a sensor, comprising the steps of:

providing a substrate;

providing at least one opening in the substrate;

placing an electrode proximate to the at least one opening; and

contacting a dry ionomer membrane to the substrate and electrode;

providing at least one hole in the ionomer membrane;

aligning the at least one hole with the at least one opening for defining a gas passage;

wherein, the ionomer membrane is dry during the steps of providing the at least one opening in the substrate, placing the electrode proximate to the at least one opening, contacting the dry ionomer membrane to the substrate and electrode, providing the at least one hole in the ionomer membrane, and aligning the at least one hole with the at least one opening.

2. The method of claim 1 further comprising the step of aligning the at least one opening in the substrate with the electrode for defining a gas passage.

3. The method of claim 1 further comprising the step of positioning a polymer layer upon the electrode for slowing inputs of gas moving through the at least one opening onto a surface of the electrode.

4. The method of claim 1 where the step of providing a substrate further includes positioning a counter electrode in contact with the dry ionomer membrane such that upon wetting the dry ionomer membrane the counter electrode provides an electrical connection.

5. The method of claim 1 where the step of providing a substrate further includes positioning a reference electrode in contact with the dry ionomer membrane such that upon wetting the dry ionomer membrane a reference point is created against which the potential of other electrodes can be measured.

6. The method of claim 1 where the step of providing a dry ionomer membrane further includes obtaining a perfluorosulfonic acid membrane.

7. The method of claim 1 further comprising the step of providing a reservoir without liquid in contact with the dry ionomer membrane.

8. The method of claim 7 further comprising the step of filling the reservoir with a liquid for hydrating the ionomer membrane.

9. The method of claim 1 further comprising the step of aligning the at least one hole with the electrode for defining a gas passage.

10. A method of making an electrochemical sensor, comprising the steps of:

providing a substrate;

placing an electrode on the substrate;

contacting a dry ionomer membrane to the substrate and electrode;

providing a hole in the dry ionomer membrane proximate to the electrode;

extending an opening in the substrate;

aligning the hole and the opening with the electrode for defining a gas passage; and

wherein, the ionomer membrane is dry during the steps of providing the opening in the substrate, placing the electrode, contacting the dry ionomer membrane to the substrate and electrode, providing the hole in the ionomer membrane, and aligning the hole and opening with the electrode for defining a gas passage.

11. The method according to claim 10, further comprising the providing a reservoir without liquid in contact with the dry ionomer membrane.

12. The method according to claim 11, further comprising the step of filling the reservoir with a liquid for hydrating the ionomer membrane.