DE4403409A1 - Moisture sensor - Google Patents

Moisture sensor

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Publication number
DE4403409A1
DE4403409A1 DE19944403409 DE4403409A DE4403409A1 DE 4403409 A1 DE4403409 A1 DE 4403409A1 DE 19944403409 DE19944403409 DE 19944403409 DE 4403409 A DE4403409 A DE 4403409A DE 4403409 A1 DE4403409 A1 DE 4403409A1
Authority
DE
Germany
Prior art keywords
polymer
moisture sensor
moisture
poly
dimethyl
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Withdrawn
Application number
DE19944403409
Other languages
German (de)
Inventor
Ludwig Prof Dr Brehmer
Mathias Dr Hahn
Michael Seifert
Roland Dr Ing Wernecke
Werner Dr Jaeger
Reiner Dipl Ing Wonneberger
Christian Dipl Ing Dr Zehner
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ZEHNER CHRISTIAN DIPL ING DR H
Original Assignee
ZEHNER CHRISTIAN DIPL ING DR H
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by ZEHNER CHRISTIAN DIPL ING DR H filed Critical ZEHNER CHRISTIAN DIPL ING DR H
Priority to DE19944403409 priority Critical patent/DE4403409A1/en
Publication of DE4403409A1 publication Critical patent/DE4403409A1/en
Withdrawn legal-status Critical Current

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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
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
    • G01N27/125—Composition of the body, e.g. the composition of its sensitive layer
    • G01N27/126—Composition of the body, e.g. the composition of its sensitive layer comprising organic polymers
    • 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
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/12—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid
    • G01N27/121—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body in dependence upon absorption of a fluid; of a solid body in dependence upon reaction with a fluid, for detecting components in the fluid for determining moisture content, e.g. humidity, of the fluid

Abstract

A moisture sensor consists of a substrate coated with a layer of poly-dimethyl-diallyl-ammonium salt (I) as moisture-sensitive polymer. Pref. a suitable substrate consists of Al2O3 ceramic, and pref. initiator is 4,4'-bisazido-stilbene- 2,2'-disulphonic acid. Pref. suitable counter-ions for (I) are chloride, nitrate, sulphate, tosylate, acetate, citrate or tartrate; pref. (I) is poly-dimethyl-diallyl-ammonium chloride (poly-DADMAC) or a copolymer of DADMAC with N-vinylpyrrolidone. The polymer also contains a UV-active crosslinking initiator. The polymer coating is applied by dipping, and a structured crosslinking effect can be obtd. by directed UV irradiation.

Description

Die Erfindung betrifft einen Polymer-Feuchtesensor, der auf einem Substrat eine dünne Schicht eines Polymers aufweist.The invention relates to a polymer moisture sensor, the a thin layer of a polymer on a substrate having.

Solche Feuchtesensoren sind bekannt: DE-PS 37 34 614.Such moisture sensors are known: DE-PS 37 34 614.

Aus SAKAI: J. o. the Electrochem. Soc., Vol. 136, No. 1, 1989 sind Untersuchungen zum Widerstandsverhalten solcher Feuchtesensoren bekannt, aus denen sich ergibt, daß Polymer-Feuchtesensoren nach dem Stand der Technik ein relativ schlechtes zeitliches Verhalten bei Feuchtigkeits­ änderungen, d. h. eine relativ lange Reaktionszeit, und darüber hinaus ein unbefriedigendes Widerstandsver­ halten aufweisen.From SAKAI: J. o. The Electrochem. Soc., Vol. 136, No. 1, 1989 are studies on the resistance behavior of such Humidity sensors are known, from which it follows that Polymer moisture sensors according to the prior art relatively poor temporal behavior with moisture changes, d. H. a relatively long reaction time, and moreover an unsatisfactory resistance resistance hold have.

Es ist Aufgabe der Erfindung, bei Feuchtesensoren der beschriebenen Gattung Widerstandsverhalten und zeitliches Verhalten bei Feuchtigkeitsänderungen zu verbessern.It is an object of the invention in the case of moisture sensors described type of resistance behavior and temporal Improve behavior with changes in moisture.

Diese Aufgabe wird durch einen Feuchtesensor mit den Merk­ malen des 1. Patentanspruches gelöst.This task is carried out by a moisture sensor with the Merk paint the 1st claim solved.

Die Unteransprüche beinhalten vorteilhafte Weiterbildungen der Erfindung.The subclaims contain advantageous developments the invention.

Es hat sich überraschenderweise gezeigt, daß die Verwendung von Poly-dimethyl-diallyl-ammoniumsalzen als spezielle kationische Polyelektrolyten als feuchtesensible Polymere zu Feuchtesensoren mit außerordentlich günstigen Eigen­ schaften führt.It has surprisingly been found that the use of poly-dimethyl-diallyl ammonium salts as special cationic polyelectrolytes as moisture-sensitive polymers to moisture sensors with extraordinarily cheap properties leads.

Zum einen besitzen die erfindungsgemäßen Feuchtesensoren ein besseres Widerstandsverhalten bei dc-Messungen als solche nach dem Stand der Technik. Sie liegen für relative Luftfeuchten von 20 . . . 95% bei Werten zwischen 2 kΩ und 1 MΩ. On the one hand, the moisture sensors according to the invention have better resistance behavior in dc measurements than those according to the prior art. They lie for relative Humidity of 20. . . 95% for values between 2 kΩ and 1 MΩ.  

Zum anderen weisen die erfindungsgemäßen Feuchtesensoren ein besseres zeitliches Verhalten bei Feuchteänderungen auf. Dies gilt speziell für die Reaktionszeit; so stellen sich innerhalb von wenigen Minuten bei veränderten Feuchtebedin­ gungen stabile Zustände ein. Bei Feuchtigkeitszunahme wird innerhalb einer Minute etwa ein Wert von 95% des Endwertes erreicht. Bei Feuchtigkeitsabnahme verlängert sich dieser Wert etwa um das 3fache.On the other hand, the moisture sensors according to the invention a better temporal behavior with changes in humidity. This applies especially to the response time; so pose within a few minutes if the humidity conditions change stable states. When moisture increases within a minute about 95% of the final value reached. This value increases when there is a decrease in moisture about 3 times.

Die erfindungsgemäß verwendeten Poly-dimethyl-diallyl-ammonium­ salze können unterschiedliche Gegenionen haben: Chlorid, Nitrat, Sulfat, Tosylat, Acetat, Citrat, Tartat.The poly-dimethyl-diallyl-ammonium used according to the invention salts can have different counterions: chloride, Nitrate, sulfate, tosylate, acetate, citrate, tartate.

Besonders vorteilhaft ist die Anwendung von Poly-dimethyl­ diallyl-ammoniumchlorid.The use of poly-dimethyl is particularly advantageous diallyl ammonium chloride.

Sehr gute Ergebnisse werden auch bei der Verwendung von Copolymeren des Dimethyl-diallyl-ammoniumchlorides mit N-Vinylpyrrolidon erzielt. Dadurch ist die Ladungsdichte des Polymers gezielt variierbar.Very good results are also obtained when using Copolymers of dimethyl-diallyl-ammonium chloride with N-vinyl pyrrolidone achieved. This is the charge density of the polymer can be specifically varied.

Eine weitere Verbesserung der Eigenschaften, insbesondere auch der Verringerung der Wasserlöslichkeit, der erfindungs­ gemäßen Feuchtesensoren ist durch eine Vernetzung, insbesondere Photovernetzung, unter vorheriger Beimischung UV-aktiver Zusatzstoffe möglich. Besonders geeignet als solcher Zusatzstoff ist 4,4′-Bisazidostilben-2,2′- disulfonsäure.A further improvement in properties, in particular also reducing the water solubility, the fiction moisture sensors is thanks to networking, especially photocrosslinking, with previous admixture UV-active additives possible. Particularly suitable as such additive is 4,4'-bisazidostilbene-2,2'- disulfonic acid.

Für die Herstellung der erfindungsgemäßen Feuchtesensoren hat sich das Dipping als Verfahren zum Bilden der Polymerschicht letztlich als besonders günstig erwiesen. Dabei wird die Filmbildung auf einem geeigneten Substrat, z. B. Al₂O₃-Keramik, durch definiertes Tauchen in eine Lösung und Herausziehen realisiert. Die überschüssige Lösung wird durch die Ober­ flächenspannung der Lösung im Tauchgefäß bei entsprechend langsamem Bewegungsablauf vom senkrecht hängenden und gut benetzten Substrat abgezogen. For the manufacture of the moisture sensors according to the invention dipping as a method of forming the polymer layer ultimately proven to be particularly cheap. The Film formation on a suitable substrate, e.g. B. Al₂O₃ ceramics, through defined immersion in a solution and extraction realized. The excess solution is through the waiter surface tension of the solution in the immersion vessel if appropriate slow movement of the vertically hanging and good wetted substrate stripped.  

Die verwendeten Polymere zeichnen sich durch eine hohe Sensibilität gegenüber Wasser aus. Das betrifft sowohl die Leitfähigkeit als auch die Löslichkeit.The polymers used are characterized by a high Sensitivity to water. That affects both Conductivity as well as solubility.

Aus diesem Grunde ist eine Vernetzung der erzeugten Schicht auf dem Substrat sinnvoll.For this reason, the layer created is cross-linked sensible on the substrate.

Vernetzungen nach der Schichtherstellung lassen sich auf verschiedene Arten durchführen:Networks after layer production can be opened perform different types:

Bekannt ist die Bestrahlung von Polymeren, so daß bestimmte Stellen des Makromoleküls aktiviert werden und eine Vernetzung zwischen diesen Molekülen erfolgen kann.The irradiation of polymers is known, so that certain Locations of the macromolecule are activated and networking can take place between these molecules.

Bekannt ist ferner das Zumischen von Monomeren und Bestrahlung der Mischung, um die Monomereinheiten als Kettenglieder zwischen den aktivierten Stellen der Makromoleküle einzusetzen.It is also known to add monomers and Irradiation of the mixture to the monomer units as Chain links between the activated sites of the macromolecules to use.

In beiden Fällen erfolgt die Aktivierung durch Gamma­ strahlung.In both cases, it is activated by gamma radiation.

Es ist auch vorgeschlagen, einen Vernetzer einzusetzen, der nach Energieeinstrahlung Verkettungen zwischen den Makromolekülen herstellt. Dabei erfolgt dann die Aktivierung durch UV-Strahlung.It is also proposed to use a crosslinker the chains between the Makes macromolecules. Then the Activation by UV radiation.

Durch gezielte UV-Bestrahlung läßt sich dabei weiterhin auch, fall erforderlich, eine strukturierte Vernetzung erreichen. Beispielsweise ist ein flächenhaftes, strukturiertes Ausarbeiten von Sensorbeschichtungen durch Ablösen der unvernetzten Fläche möglich.Targeted UV radiation can still be used also, if necessary, structured networking to reach. For example, structured elaboration of sensor coatings through Detachment of the uncrosslinked area possible.

Claims (7)

1. Feuchtesensor, bestehend aus einer auf ein Substrat aufgezogenen Schicht eines feuchtesensiblen Polymers, dadurch gekennzeichnet, daß das Polymer ein Poly-dimethyl-diallyl-ammoniumsalz ist.1. Moisture sensor, consisting of a layer of a moisture-sensitive polymer applied to a substrate, characterized in that the polymer is a poly-dimethyl-diallyl-ammonium salt. 2. Feuchtesensor nach Anspruch 1, dadurch gekennzeichnet, daß das Polymer als Gegenionen Chlorid, Nitrat, Sulfat, Tosylat, Acetat, Citrat oder Tartrat aufweist.2. Moisture sensor according to claim 1, characterized, that the polymer as counterions are chloride, nitrate, sulfate, Has tosylate, acetate, citrate or tartrate. 3. Feuchtesensor nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß das Polymer ein Poly-dimethyl-diallyl-ammoniumchlorid ist.3. Moisture sensor according to claim 1 or 2, characterized, that the polymer is a poly-dimethyl-diallyl-ammonium chloride is. 4. Feuchtesensor nach Anspruch 1 bis 3, dadurch gekennzeichnet, daß das Polymer ein Copolymer des Dimethyl-diallyl­ ammoniumchlorides mit N-Vinylpyrrolidon ist.4. Moisture sensor according to claim 1 to 3, characterized, that the polymer is a copolymer of dimethyl-diallyl ammoniumchlorides with N-vinylpyrrolidone. 5. Feuchtesensor nach Anspruch 1 bis 4, dadurch gekennzeichnet, daß dem Polymer ein UV-aktiver Zusatzstoff zur Vernetzung nach dem Aufziehen beigemischt ist.5. Moisture sensor according to claim 1 to 4, characterized, that the polymer has a UV-active additive Crosslinking is added after winding up. 6. Feuchtesensor nach Anspruch 1 bis 5, dadurch gekennzeichnet, daß das Polymer durch Dipping auf das Substrat aufziehbar ist.6. Moisture sensor according to claim 1 to 5, characterized, that the polymer by dipping onto the substrate is windable. 7. Feuchtesensor nach Anspruch 1 bis 6, dadurch gekennzeichnet, daß durch gezielte UV-Bestrahlung eine strukturierte Vernetzung erreichbar ist.7. Moisture sensor according to claim 1 to 6, characterized, that a structured by targeted UV radiation Networking is achievable.
DE19944403409 1994-02-04 1994-02-04 Moisture sensor Withdrawn DE4403409A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE19944403409 DE4403409A1 (en) 1994-02-04 1994-02-04 Moisture sensor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19944403409 DE4403409A1 (en) 1994-02-04 1994-02-04 Moisture sensor

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DE4403409A1 true DE4403409A1 (en) 1995-08-10

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0676636A2 (en) * 1994-03-31 1995-10-11 TDK Corporation Humidity sensor and method for making
DE19963188A1 (en) * 1998-12-28 2000-09-14 Tdk Corp Moisture sensitive elements utilizing moisture absorbing polymer
EP1369683A1 (en) * 2001-03-13 2003-12-10 TDK Corporation Humidity sensor element and method for manufacture thereof
FR2923218A1 (en) * 2007-11-06 2009-05-08 Rhodia Operations Sas Composition, useful to treat and/or modify surface e.g. textile, comprises copolymer comprising cationic units A and other units B, where unit A comprises quaternary ammonium/inium group, and unit B comprises vinyl-lactam
WO2009059878A1 (en) * 2007-11-06 2009-05-14 Rhodia Operations Copolymer for processing or modifying surfaces
FR2928377A1 (en) * 2008-03-06 2009-09-11 Rhodia Operations Sas Composition, useful to treat and/or modify surface e.g. textile, comprises copolymer comprising cationic units and other units, where the cationic unit comprises quaternary ammonium/inium group and other unit comprises vinyl-lactam

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0676636A2 (en) * 1994-03-31 1995-10-11 TDK Corporation Humidity sensor and method for making
EP0676636A3 (en) * 1994-03-31 1996-11-13 Tdk Corp Humidity sensor and method for making.
DE19963188A1 (en) * 1998-12-28 2000-09-14 Tdk Corp Moisture sensitive elements utilizing moisture absorbing polymer
US6342295B1 (en) 1998-12-28 2002-01-29 Tdk Corporation Moisture sensor
EP1369683A1 (en) * 2001-03-13 2003-12-10 TDK Corporation Humidity sensor element and method for manufacture thereof
EP1369683A4 (en) * 2001-03-13 2008-06-18 Tdk Corp Humidity sensor element and method for manufacture thereof
FR2923218A1 (en) * 2007-11-06 2009-05-08 Rhodia Operations Sas Composition, useful to treat and/or modify surface e.g. textile, comprises copolymer comprising cationic units A and other units B, where unit A comprises quaternary ammonium/inium group, and unit B comprises vinyl-lactam
WO2009059878A1 (en) * 2007-11-06 2009-05-14 Rhodia Operations Copolymer for processing or modifying surfaces
US9096817B2 (en) 2007-11-06 2015-08-04 Rhodia Operations Copolymer for processing or modifying surfaces
FR2928377A1 (en) * 2008-03-06 2009-09-11 Rhodia Operations Sas Composition, useful to treat and/or modify surface e.g. textile, comprises copolymer comprising cationic units and other units, where the cationic unit comprises quaternary ammonium/inium group and other unit comprises vinyl-lactam

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