DE4019855A1 - Gas diffusion barrier for electrochemical gas sensors - consists of thin layer of poly-di:methyl-siloxane, pref. applied to working electrode or its supporting film - Google Patents
Gas diffusion barrier for electrochemical gas sensors - consists of thin layer of poly-di:methyl-siloxane, pref. applied to working electrode or its supporting filmInfo
- Publication number
- DE4019855A1 DE4019855A1 DE4019855A DE4019855A DE4019855A1 DE 4019855 A1 DE4019855 A1 DE 4019855A1 DE 4019855 A DE4019855 A DE 4019855A DE 4019855 A DE4019855 A DE 4019855A DE 4019855 A1 DE4019855 A1 DE 4019855A1
- Authority
- DE
- Germany
- Prior art keywords
- gas
- diffusion barrier
- solubility membrane
- siloxane
- layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/403—Cells and electrode assemblies
- G01N27/404—Cells with anode, cathode and cell electrolyte on the same side of a permeable membrane which separates them from the sample fluid, e.g. Clark-type oxygen sensors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0011—Sample conditioning
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
Abstract
Description
Elektrochemische Gassensoren benötigen eine Gasströmungsbarriere, damit die Kinetik der Arbeitselektrode eines derartigen Sensors durch ein physikalisches Gastransportphänomen und nicht durch ihre katalytische Aktivität begrenzt wird. Durch diese Transport begrenzung kann erreicht werden, daß die Empfindlichkeit des Sensors einige Jahre aufrechterhalten wird, obwohl die kataly tische Aktivität - d. h. die Reaktionsfähigkeit der Arbeits elektrode - im Laufe der Zeit auf Grund verschiedener Einflüsse, wie z. B. Vergiftung, nachläßt.Electrochemical gas sensors require a gas flow barrier, thus the kinetics of the working electrode of such a sensor through a physical gas transport phenomenon and not through their catalytic activity is limited. Through this transportation limit can be achieved that the sensitivity of the Sensor is maintained for several years, although the kataly table activity - d. H. the responsiveness of work electrode - over time due to various influences, such as B. poisoning, subsides.
Eine solche Begrenzung wird z. B. durch die Verwendung einer Gas diffusionsbarriere von der Firma City Technology im deutschen Patent 27 09 903 vorgeschlagen.Such a limitation is e.g. B. by using a gas diffusion barrier from City Technology in Germany Patent 27 09 903 proposed.
Andere Möglichkeiten der Gaszufuhrbegrenzung sind verschiedene Kunststoffmembranen, wie Polyethylen, Teflon, Silikongummi usw., die über der Arbeitselektrode aufgespannt werden und die Gaszu fuhr zu dieser Elektrode begrenzen. Sauerstoffzellen mit solchen Membranen sind aus mehreren Patenten und Veröffentlichungen be kannt. Diese Membran-Gaszufuhrbegrenzung hat gegenüber einer Kapillare mehrere Vorteile; z. B. kann die Verdunstung der Elektrolytflüssigkeit verhindert werden oder es können durch selektiven Durchlaß eines Gases (z. B. Sauerstoff) störende Querempfindlichkeiten unterdrückt oder schädliche Gase (Vergif tung der Arbeitselektrode) zurückgehalten werden.Other ways of limiting gas supply are different Plastic membranes such as polyethylene, teflon, silicone rubber, etc., which are clamped over the working electrode and the gas drove to this electrode limit. Oxygen cells with such Membranes are from several patents and publications knows. This membrane gas supply restriction has one Capillary several advantages; e.g. B. can the evaporation of Electrolyte fluid can be prevented or it can get through selective passage of a gas (e.g. oxygen) disturbing Cross-sensitivity suppressed or harmful gases (Vergif tion of the working electrode) are retained.
Ein Nachteil dieses Verfahrens ist, daß auf Folien zurückgegrif fen werden muß die nur aus bestimmten Materialien mit herstel lungstechnisch bedingten minimalen Schichtdicken (meist über 10 µm) gefertigt werden können. Diese Tatsache hat zur Folge, daß wegen der relativ großen Dicke der Membranen nur wenige Gase, nämlich hauptsächlich solche, die in höheren Konzentrationen vorliegen (z. B. Sauerstoff in Luft: ca. 20 Vol.-%), mit aus reichender Geschwindigkeit durchdiffundieren können. Aus diesem Grund existieren nur Sauerstoff-Sensoren mit Kunststoffmembran- Diffusionsbegrenzung. Für andere Gase, wie z. B. Kohlenmonoxid oder Schwefelwasserstoff, die in der Regel nur in Konzentratio nen von einigen bis einigen zehn ppm in der Umgebungsatmosphäre vorliegen, gibt es keine Möglichkeit, mit diesen Folien eine Transportbegrenzung aufzubauen.A disadvantage of this method is that it uses foils must only be made from certain materials lung-related minimum layer thicknesses (mostly about 10 µm) can be manufactured. This fact means that only a few gases due to the relatively large thickness of the membranes, namely mainly those in higher concentrations are present (e.g. oxygen in air: approx. 20 vol.%), with off diffuse at sufficient speed. For this For this reason, there are only oxygen sensors with plastic membrane Diffusion limitation. For other gases, such as B. carbon monoxide or hydrogen sulfide, which is usually only in concentration from a few to a few tens of ppm in the ambient atmosphere there is no possibility of using these foils To build up transport limits.
Unser Verfahren gestattet es, aus flüssigem Siloxan sehr dünne Polysiloxan-Membranen herzustellen. Das Herstellungsverfahren erlaubt es, die Schichtdicke beliebig zwischen 50 µm und 10 µm zu variieren. Dadurch ist es nunmehr möglich: mit Polysiloxan- Membranen geeigneter Dicke Gasdiffusionsbarrieren aufzubauen und zwar nicht nur für Sauerstoff sondern auch für Komponenten: die in Konzentrationen von nur einigen zehn ppm in dem zu messenden Gasgemisch vorhanden sind, insbesondere Kohlenmonoxid, Schwefel wasserstoff: Schwefeldioxid u. a. Our process allows very thin from liquid siloxane To produce polysiloxane membranes. The manufacturing process allows the layer thickness to be between 50 µm and 10 µm vary. It is now possible: with polysiloxane Build membranes of suitable thickness and gas diffusion barriers not only for oxygen but also for components: the in concentrations of only a few tens of ppm in the sample to be measured Gas mixture are present, especially carbon monoxide, sulfur hydrogen: sulfur dioxide and a.
Da eine weitere Handhabung dieser Membranen nach ihrer Herstellung nicht mehr möglich ist, ist es vorteilhaft, die Polysiloxan-Schicht jeweils sofort auf die Arbeitselektrode aufzubringen.Since further handling of these membranes according to their Manufacturing is no longer possible, it is advantageous to Polysiloxane layer immediately on the working electrode to apply.
Im Hinblick auf das Material ist es von Vorteil, von Dimethyl siloxan auszugehen. Im Verlaufe des Vorgangs des Trocknens und Temperns entsteht ein Polydimethylsiloxan-Film, der einerseits chemisch sehr beständig ist, andererseits gute Transportkoeffi zienten im Hinblick auf die meisten zu messenden Gaskomponenten (z. B. Kohlenmonoxid, Schwefelwasserstoff und Schwefeldioxid) aufweist.In terms of material, it is advantageous to use dimethyl going out siloxane. In the course of the drying process and Annealing creates a polydimethylsiloxane film, on the one hand chemically very stable, on the other hand good transport coefficient targeted with most gas components to be measured (e.g. carbon monoxide, hydrogen sulfide and sulfur dioxide) having.
Ein elektrochemischer Sensor, aufgebaut aus drei Elektroden (eine Arbeitselektrode, eine Referenzelektrode und eine Gegenelektrode), wobei die Elektroden schichtweise aufeinander gestapelt sind und nur die Arbeitselektrode mit dem zu messenden Medium in Berührung kommt. Die Elektroden des Sensors werden aus poröser Teflon-Folie, beschichtet mit Platin-Katalysator, hergestellt. Nach Herstellung der Arbeitselektrode wird auf dieser noch eine zusätzliche Polydimethylsiloxan-Schicht aufgebracht. Hierzu wird die fertige Elektrode auf einer Zentrifuge befestigt. Dann wird aus einer Dimethylsiloxan-Lösung eine dünne Schicht gleichmäßig auf die äußere Oberfläche der Teflon-Folie aufzentrifugiert. Diese Schicht wird getrocknet und getempert, so daß ein Polydimethylsiloxan-Film entsteht. Die derart hergestellte Arbeitselektrode wird in die elektrochemische Zelle eingebaut. Diese Elektrode hat also folgenden Aufbau: Eine poröse Teflonfolie dient als Träger für die Platinelektroden- Beschichtung auf einer Seite, die dann im Kontakt mit dem Elektrolyten steht. Auf der anderen Seite befindet sich die auf Teflon aufgebrachte sehr dünne Polydimethylsiloxan-Schicht.An electrochemical sensor made up of three electrodes (a working electrode, a reference electrode and a Counterelectrode), the electrodes being layered on top of each other are stacked and only the working electrode with the one to be measured Medium comes into contact. The electrodes of the sensor are off porous Teflon film, coated with platinum catalyst, produced. After manufacturing the working electrode is on this still an additional polydimethylsiloxane layer upset. For this, the finished electrode is placed on a Centrifuge attached. Then a dimethylsiloxane solution apply a thin layer evenly to the outer surface of the Centrifuged Teflon film. This layer is dried and annealed so that a polydimethylsiloxane film is formed. The Working electrode produced in this way is used in the electrochemical Cell installed. So this electrode has the following structure: A porous Teflon foil serves as a carrier for the platinum electrode Coating on one side, which is then in contact with the Electrolyte stands. On the other side is the Teflon applied very thin polydimethylsiloxane layer.
Claims (21)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE4019855A DE4019855A1 (en) | 1990-06-22 | 1990-06-22 | Gas diffusion barrier for electrochemical gas sensors - consists of thin layer of poly-di:methyl-siloxane, pref. applied to working electrode or its supporting film |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE4019855A DE4019855A1 (en) | 1990-06-22 | 1990-06-22 | Gas diffusion barrier for electrochemical gas sensors - consists of thin layer of poly-di:methyl-siloxane, pref. applied to working electrode or its supporting film |
Publications (1)
Publication Number | Publication Date |
---|---|
DE4019855A1 true DE4019855A1 (en) | 1992-11-19 |
Family
ID=6408841
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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DE4019855A Withdrawn DE4019855A1 (en) | 1990-06-22 | 1990-06-22 | Gas diffusion barrier for electrochemical gas sensors - consists of thin layer of poly-di:methyl-siloxane, pref. applied to working electrode or its supporting film |
Country Status (1)
Country | Link |
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DE (1) | DE4019855A1 (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1994015806A1 (en) * | 1993-01-14 | 1994-07-21 | Robert Bosch Gmbh | Measuring device for detecting pollution in the fresh air to be fed especially into a vehicle passenger compartment |
WO1995019563A1 (en) * | 1994-01-14 | 1995-07-20 | Neotronics Limited | Gas sensor |
DE4439286C2 (en) * | 1994-11-07 | 2003-07-31 | Gerhard Reis | Multi-layer and edge-mounted membrane body for the electrochemical measuring cell and method for its production |
DE102011119484A1 (en) | 2011-11-28 | 2013-05-29 | Elena König | Membrane for the determination of gases in non-aqueous liquids, method for the production of the membrane, measuring arrangement and method for the determination of gases in non-aqueous liquids |
US8916037B1 (en) * | 2006-08-31 | 2014-12-23 | Mocon, Inc. | Instrument and method for measuring high concentrations of carbon monoxide in a gaseous sample |
CN110437449A (en) * | 2019-08-13 | 2019-11-12 | 青岛科技大学 | The method that a kind of ring-opening polymerisation of cyclosiloxane original position prepares polysiloxane film |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4781798A (en) * | 1985-04-19 | 1988-11-01 | The Regents Of The University Of California | Transparent multi-oxygen sensor array and method of using same |
JPH01267971A (en) * | 1988-04-19 | 1989-10-25 | Matsushita Electric Ind Co Ltd | Battery |
JPH01267970A (en) * | 1988-04-19 | 1989-10-25 | Matsushita Electric Ind Co Ltd | Battery |
US4894253A (en) * | 1986-08-12 | 1990-01-16 | University Of Cincinnati | Method for production of coated electrode |
DE3841622A1 (en) * | 1988-12-10 | 1990-06-13 | Draegerwerk Ag | ELECTROCHEMICAL MEASURING CELL FOR THE AMPEROMETRIC DETERMINATION OF AMMONIA AND ITS DERIVATIVES |
-
1990
- 1990-06-22 DE DE4019855A patent/DE4019855A1/en not_active Withdrawn
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4781798A (en) * | 1985-04-19 | 1988-11-01 | The Regents Of The University Of California | Transparent multi-oxygen sensor array and method of using same |
US4894253A (en) * | 1986-08-12 | 1990-01-16 | University Of Cincinnati | Method for production of coated electrode |
JPH01267971A (en) * | 1988-04-19 | 1989-10-25 | Matsushita Electric Ind Co Ltd | Battery |
JPH01267970A (en) * | 1988-04-19 | 1989-10-25 | Matsushita Electric Ind Co Ltd | Battery |
DE3841622A1 (en) * | 1988-12-10 | 1990-06-13 | Draegerwerk Ag | ELECTROCHEMICAL MEASURING CELL FOR THE AMPEROMETRIC DETERMINATION OF AMMONIA AND ITS DERIVATIVES |
US4961834A (en) * | 1988-12-10 | 1990-10-09 | Dragerwerk Aktiengesellschaft | Electrochemical measuring cell for amperometrically determining ammonia and derivatives thereof |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1994015806A1 (en) * | 1993-01-14 | 1994-07-21 | Robert Bosch Gmbh | Measuring device for detecting pollution in the fresh air to be fed especially into a vehicle passenger compartment |
WO1995019563A1 (en) * | 1994-01-14 | 1995-07-20 | Neotronics Limited | Gas sensor |
DE4439286C2 (en) * | 1994-11-07 | 2003-07-31 | Gerhard Reis | Multi-layer and edge-mounted membrane body for the electrochemical measuring cell and method for its production |
US8916037B1 (en) * | 2006-08-31 | 2014-12-23 | Mocon, Inc. | Instrument and method for measuring high concentrations of carbon monoxide in a gaseous sample |
DE102011119484A1 (en) | 2011-11-28 | 2013-05-29 | Elena König | Membrane for the determination of gases in non-aqueous liquids, method for the production of the membrane, measuring arrangement and method for the determination of gases in non-aqueous liquids |
WO2013079052A1 (en) | 2011-11-28 | 2013-06-06 | Koenig Elena | Plasma polymer membrane |
CN110437449A (en) * | 2019-08-13 | 2019-11-12 | 青岛科技大学 | The method that a kind of ring-opening polymerisation of cyclosiloxane original position prepares polysiloxane film |
CN110437449B (en) * | 2019-08-13 | 2024-01-02 | 青岛科技大学 | Method for preparing polysiloxane film by in-situ ring-opening polymerization of cyclosiloxane |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
8101 | Request for examination as to novelty | ||
8105 | Search report available | ||
8127 | New person/name/address of the applicant |
Owner name: ENDRESS + HAUSER GASTEC GMBH + CO, 44227 DORTMUND, |
|
8127 | New person/name/address of the applicant |
Owner name: ENDRESS + HAUSER CONDUCTA GESELLSCHAFT FUER MESS- |
|
8139 | Disposal/non-payment of the annual fee |