US5756879A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Volatile organic compound sensors
Assignee: The AT&T MVPD Group LLC
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Filing: 1996-07-25
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Granted: 1998-05-26
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Expires: 2016-07-25
Abstract
Abstract A novel, inexpensive sensor and method for detecting volatile compounds in the gas phase at concentrations of less than about 500 ppm in ambient air are provided. The sensor comprises (a) a dielectric substrate having a major surface; (b) a pair of electrically conductive electrodes disposed on the major surface of the substrate; and (c) a conductive polymer covering the pair of electrically conductive electrodes, with the conductive polymer doped with appropriate dopants in measurable excess of that stoichiometrically required to change the conductive polymer from a neutral state to a charged state to provide requisite conductivity. A method for making the sensor is provided, as is a method of use of the sensor which relates to its use in a monitoring system comprising a means for measuring the conductivity of the sensor connected to a warning means for providing an indication when the conductivity reaches a predetermined level. Contemplated specific methods of use include the detection of fugitive emissions in chemical plant environments; the detection of certain pollutants in vehicle exhaust; and the detection of certain pollutants near chemical handling operations, such as painting operations.\!
Inventors
- 👤 Frederick G. Yamagishi
- 👤 Thomas B. Stanford
- 👤 Camille I. Van Ast
- 👤 Leroy J. Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:58
CPC Classifications
G; G01; G01N; G01N27/00; G01N27/02; G01N27/04; G01N27/12; G01N27/125; G01N27/126; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/3154
Claims Analysis
Total Claims: 44
Claim 1
Independent Claim
132 words
The invention claimed is a sensor for reversibly detecting target volatile material in the gas phase comprising: (a) a dielectric substrate having a major surface; (b) a pair of electrically conductive electrodes disposed on said major surface of said substrate; and (c) a conductive polymer covering said pair of electrically conductive electrodes, said conductive polymer doped with appropriate dopants, said dopants present in said conductive polymer in measurable excess of that stoichiometrically required to change said conductive polymer from a neutral state to a charged state to provide requisite conductivity, said sensor being capable of detecting the presence of said target volatile material at a concentration of less than about 500 ppm. wherein said dielectric substrate is deactivated by a surface treatment means that enhances the hydrophobicity of surface on said substrate.
Claim 2
Dependent Claim
40 words
The invention claimed is the sensor of claim 1 wherein said conductive polymer is prepared by spin-casting from dilute organic solutions having a concentration of less than about 10% and wherein said dilute organic solutions are substantially free of agglomeration.
Claim 3
Dependent Claim
33 words
The invention claimed is the sensor of claim 2 wherein said sensor is capable of detecting the presence of said target volatile material at a concentration of less than about 1 00 ppm.
Claim 4
Dependent Claim
28 words
The invention claimed is the sensor of claim 1 wherein said electrically conductive electrodes comprise a material selected from the group consisting of gold, platinum, palladium, and carbon.
Claim 5
Dependent Claim
18 words
The invention claimed is the sensor of claim 4 wherein said electrically conductive electrodes consist essentially of gold.
Claim 6
Dependent Claim
27 words
The invention claimed is the sensor of claim 5 wherein said gold electrodes are formed on an adhering layer that adheres said gold electrodes to said substrate.
Claim 7
Dependent Claim
34 words
The invention claimed is the sensor of claim 1 wherein said conductive polymer is selected from the group consisting of polyaniline, polythiophene, polypyrrole, poly(p-phenylene vinylene), derivatives of these polymers, and mixtures of these materials.
Claim 8
Dependent Claim
36 words
The invention claimed is the sensor of claim 7 wherein conductive polymer is polyaniline and said dopants are selected from the group consisting of p-toluenesulfonate, copper phthalocyanine-tetrasulfonate, poly(styrenesulfonate), camphorsulfonate, dodecylbenzenesulfonate, butanesulfonate, octanesulfonate, hexadecanesulfonate, octadecanesulfonate, and bisulfate.
Claim 9
Dependent Claim
41 words
The invention claimed is the sensor of claim 1 wherein said measurable excess is about one part over that stoichiometrically required to change one part of said conductive polymer from a neutral state to a charged state to provide requisite conductivity.
Claim 10
Dependent Claim
27 words
The invention claimed is the sensor of claim 1 wherein said dielectric substrate comprises a material selected from the group consisting of glass, ceramics and dielectric polymers.
Claim 11
Dependent Claim
30 words
The invention claimed is the sensor of claim 10 wherein said dielectric substrate comprises a glass selected from the group consisting of silica, phosphate, and borate glasses and mixtures thereof.
Claim 12
Dependent Claim
29 words
The invention claimed is the sensor of claim 10 wherein said dielectric substrate comprises a ceramic selected from the group consisting of alumina, magnesia, calcia, quartz, and mixtures thereof.
Claim 13
Dependent Claim
30 words
The invention claimed is the sensor of claim 10 wherein said dielectric substrate comprises a dielectric polymer selected from the group consisting of polyethylene terephthalate, poly(tetrafluoroethylene), poly(methyl methacrylate), and polyimides.
Claim 14
Dependent Claim
162 words
The invention claimed is a method of making a sensor for reversibly detecting target volatile material in the gas phase comprising: (a) providing a dielectric substrate having a major surface; (b) disposing a pair of electrically conductive electrodes on said major surface of said substrate; and (c) preparing a conductive polymer for disposition on said electrically conductive electrodes by doping said conductive polymer with an excess of appropriate dopants, said dopants present in said conductive polymer in measurable excess of that stoichiometrically required to change said conductive polymer from a neutral state to a charged state to provide requisite conductivity; and (d) covering said pair of electrically conductive electrodes with said doped conductive polymer, said sensor being capable of detecting the presence of said target volatile material at a concentration of less than about 500 ppm, further comprising step (a',) following step (a): (a') deactivating said dielectric substrate by a surface treatment means that enhances the hydrophobicity of surface on said substrate.
Claim 15
Dependent Claim
34 words
The invention claimed is the method of claim 14 wherein said dielectric substrate is deactivated by silation with a silating agent selected from the group consisting of hexamethyidisilazane, N-phenylaminopropyltrimethoxysilane, octyltrishlorosilane, octyltrimethoxysilane, octadecyltrichlorosilane and octadecyltrimethoxysilane.
Claim 16
Dependent Claim
28 words
The invention claimed is the method of claim 14 wherein said electrically conductive electrodes comprise a material selected from the group consisting of gold, platinum, palladium, and carbon.
Claim 17
Dependent Claim
27 words
The invention claimed is the method of claim 14 wherein said dielectric substrate comprises a material selected from the group consisting of glass, ceramics, and dielectric polymers.
Claim 18
Dependent Claim
192 words
The invention claimed is a method of making a sensor for reversibly detecting target volatile material in the gas phase comprising: (a) providing a dielectric substrate having a major surface; (b) disposing a pair of electrically conductive electrodes on said major surface of said substrate; and (c) preparing a conductive polymer for disposition on said electrically conductive electrodes by doping said conductive polymer with an excess of appropriate dopants, said dopants present in said conductive polymer in measurable excess of that stoichiometrically required to change said conductive polymer from a neutral state to a charged state to provide requisite conductivity; and (d) covering said pair of electrically conductive electrodes with said doped conductive polymer. said sensor being capable of detecting the presence of said target volatile material at a concentration of less than about 500 ppm. wherein said electrically conductive electrodes comprise a material selected from the group consisting of gold, platinum, palladium and carbon, and wherein said electrically conductive electrodes consist essentially of gold and wherein said method further comprises a step (a") immediately prior to step (b): (a") depositing an adhering layer on said dielectric substrate comprising a tungsten--titanium alloy.
Claim 19
Dependent Claim
34 words
The invention claimed is the method of claim 14 wherein said conductive polymer is selected from the group consisting of polyaniline, polythiophene, polypyrrole, poly(p-phenylene vinylene), derivatives of these polymers, and mixtures of these materials.
Claim 20
Dependent Claim
37 words
The invention claimed is the method of claim 19 wherein said conductive polymer is polyaniline and said dopants are selected from the group consisting of p-toluenesulfonate, copper phthalocyaninetetrasulfonate, poly(styrenesulfonate), camphorsulfonate, dodecylbenzenesulfonate, butanesulfonate, octanesulfonate, hexadecanesulfonate, octadecanesulfonate, and bisulfate.
Claim 21
Dependent Claim
31 words
The invention claimed is the method of claim 14 wherein step (c) further comprises spin-casting said conductive polymer from a dilute organic solution having a concentration of less than about 10%.
Claim 22
Dependent Claim
21 words
The invention claimed is the method of claim 21 wherein step (c) further comprises minimizing agglomeration in said dilute organic solution.
Claim 23
Dependent Claim
16 words
The invention claimed is the method of claim 22 wherein said agglomeration is minimized by ultrasonication.
Claim 24
Dependent Claim
32 words
The invention claimed is the method of claim 22 wherein said sensor is capable of detecting the presence of said target volatile material at a concentration of less than about 100 ppm.
Claim 25
Dependent Claim
41 words
The invention claimed is the method of claim 14 wherein said measurable excess is about one part over that stoichiometrically required to change one part of said conductive polymer from a neutral state to a charged state to provide requisite conductivity.
Claim 26
Dependent Claim
29 words
The invention claimed is the method of claim 14 further comprising step (d): (d) drying said doped conductive polymer prior to exposing said sensor to said target volatile material.
Claim 27
Dependent Claim
226 words
The invention claimed is a method of detecting a target volatile material in ambient air, said method comprising the steps of: (a) providing a sensor comprising: (i) a dielectric substrate having a major surface; (ii) a pair of electrically conductive electrodes disposed on said major surface of said substrate, and (iii) a conductive polymer covering said pair of electrically conductive electrodes, said conductive polymer doped with appropriate dopants, said dopants present in said conductive polymer in measurable excess of that stoichiometrically required to change said conductive polymer from a neutral state to a charged state to provide requisite conductivity, said conductive polymer having a conductivity that changes as a function of the presence of said target volatile material, said sensor being capable of detecting the presence of said target volatile material at a concentration of less than about 500 ppm; (b) exposing said sensor to ambient air to generate a signal that is a function of said conductivity; and (c) monitoring said conductivity of said conductive polymer, said method resulting in the detection of said target volatile material at a concentration of less than about 500 ppm. wherein said dielectric substrate comprises a material selected from the group consisting of glass, ceramics, and dielectric polymers, and wherein said dielectric substrate is deactivated by a surface treatment means that enhances the hydrophobicity of surface on said substrate.
Claim 28
Dependent Claim
40 words
The invention claimed is the method of claim 27 wherein said conductive polymer is prepared by spin-casting from dilute organic solutions having a concentration of less than about 10% and wherein said dilute organic solutions are substantially free of agglomeration.
Claim 29
Dependent Claim
31 words
The invention claimed is the method of claim 28 wherein said sensor is capable of detecting the presence of said volatile material at a concentration of less than about 100 ppm.
Claim 30
Dependent Claim
28 words
The invention claimed is the method of claim 27 wherein said electrically conductive electrodes comprise a material selected from the group consisting of gold, platinum, palladium, and carbon.
Claim 31
Dependent Claim
18 words
The invention claimed is the method of claim 30 wherein said electrically conductive electrodes consist essentially of gold.
Claim 32
Dependent Claim
27 words
The invention claimed is the method of claim 31 wherein said gold electrodes are formed on an adhering layer that adheres said gold electrodes to said substrate.
Claim 33
Dependent Claim
34 words
The invention claimed is the method of claim 27 wherein said conductive polymer is selected from the group consisting of polyaniline, polythiophene, polypyrrole, poly(p-phenylene vinylene), derivatives of these polymers, and mixtures of these materials.
Claim 34
Dependent Claim
37 words
The invention claimed is the method of claim 27 wherein said conductive polymer is polyaniline and said dopants are selected from the group consisting of p-toluenesulfonate, copper phthalocyaninetetrasulfonate, poly(styrenesulfonate), camphorsulfonate, dodecylbenzenesulfonate, butanesulfonate, octanesulfonate, hexadecanesulfonate, octadecanesulfonate, and bisulfate.
Claim 35
Dependent Claim
41 words
The invention claimed is the method of claim 27 wherein said measurable excess is about one part over that stoichiometrically required to change one part of said conductive polymer from a neutral state to a charged state to provide requisite conductivity.
Claim 36
Dependent Claim
34 words
The invention claimed is the method of claim 27 wherein said step of exposing comprises placing said sensor in the vicinity of an area of concern regarding the presence of said target volatile material.
Claim 37
Dependent Claim
21 words
The invention claimed is the method of claim 27 wherein said step of monitoring comprises measuring the conductivity between said electrodes.
Claim 38
Dependent Claim
172 words
The invention claimed is a method of using a sensor for reversibly detecting a target volatile material in the gas phase comprising a dielectric substrate having a major surface: a pair of electrically conductive electrodes disposed on said major surface of said substrate; and a coating covering said pair of electrically conductive electrodes, said coating consisting essentially of at least one conductive polymer doped to achieve a requisite conductivity and to have an affinity for said target volatile material, said method comprising the steps of: (a) connecting said sensor to a mechanism capable of communicating the presence of said target volatile material upon detection thereof by said sensor; and (b) positioning said sensor such that said sensor is exposed to ambient air in an area of concern regarding the presence of said target volatile material, wherein said target volatile material is chemical weapon simulant material and said area of concern is selected from the group consisting of the vicinity of a potential chemical weapon deployment and the vicinity of chemical weapon manufacture.
Claim 39
Dependent Claim
30 words
The invention claimed is the method of claim 38 wherein said area of concern is in the vicinity of human handling of a material potentially containing said target volatile material.
Claim 40
Dependent Claim
102 words
The invention claimed is the method of claim 38 wherein said at least one conductive polymer is doped with appropriate dopants, said dopants present in said at least one conductive polymer in measurable excess of that stoichiometrically required to change said at least one conductive polymer from a neutral state to a charged state to provide requisite conductivity, said at least one conductive polymer having a conductivity that changes as a function of the presence of said target volatile material, said sensor being capable of detecting the presence of said target volatile material at a concentration of less than about 500 ppm.
Claim 41
Dependent Claim
208 words
The invention claimed is a method of using a sensor for reversibly detecting a target volatile material in the gas phase comprising a dielectric substrate having a major surface; a pair of electrically conductive electrodes disposed on said major surface of said substrate: and a coating covering said pair of electrically conductive electrodes, said coating consisting essentially of at least one conductive polymer doped to achieve a requisite conductivity and to have an affinity for said target volatile material said method comprising the steps of: (a) connecting said sensor to a mechanism capable of communicating the presence of said target volatile material upon detection thereof by said sensor; and (b) positioning said sensor such that said sensor is exposed to ambient air in an area of concern regarding the presence of said target volatile material, wherein said dielectric substrate is deactivated by a surface treatment means that enhances the hydrophobicity of surface on said substrate, wherein said conductive polymer is prepared by spin-casting from dilute organic solutions having a concentration of less than about 10%, and wherein said dilute organic solutions are substantially free of agglomeration, said sensor being capable of detecting the presence of said target volatile material at a concentration of less than about 100 ppm.
Claim 42
Dependent Claim
244 words
The invention claimed is a monitoring system for monitoring the content of a target volatile material in ambient air, said monitoring system, comprising: (a) at least one sensor for reversibly detecting said target volatile material in the gas phase, said at least one sensor positioned to be exposed to said ambient air, said at least one sensor comprising; (i) a dielectric substrate having a major surface; (ii) a pair of electrically conductive electrodes disposed on said major surface of said substrate; and (iii) a conductive polymer covering said pair of electrically conductive electrodes, said conductive polymer doped with appropriate dopants, said dopants present in said conductive polymer in measurable excess of that stoichiometrically required to change said conductive polymer from a neutral state to a charged state to provide requisite conductivity, said conductive polymer having a conductivity that changes as a function of the presence of said target volatile material, said sensor being capable of detecting the presence of said target volatile material at a concentration of less than about 500 ppm, wherein said dielectric substrate is deactivated by a surface treatment means that enhances the hydrophobicity of surface on said substrate; (b) a conductivity detector for measuring the conductivity of the sensor, said conductivity detector being capable of indicating when said conductivity reaches a predetermined level; (c) an alarm for providing an indication when said predetermined level is reached; and (d) interconnectors for interconnecting said sensor and said alarm to said conductivity detector.
Claim 43
Dependent Claim
21 words
The invention claimed is the monitoring system of claim 42 wherein said at least one sensor comprises an array of sensors.
Claim 44
Dependent Claim
36 words
The invention claimed is the monitoring system of claim 42 wherein said at least one sensor is capable of detecting the presence of said target volatile material at a concentration of less than about 100 ppm.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-05-25 | 2001-11-24 | 2002-05-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-05-25 | 2005-11-24 | 2006-05-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-05-25 | 2009-11-24 | 2010-05-26 | $7700.00 | Window Closed / Lapsed |