JP5211456B2 - Environmental component evaluation sensor - Google Patents

Description

  The present invention relates to a polymer film having reduced conductivity and an environmental component evaluation sensor using the polymer film.

  Sensor devices that apply electrochemical detection principles, such as humidity sensors, gas sensors, and odor sensors, are indispensable devices for air conditioning management and safety devices in buildings and homes.

For example, a humidity sensor or the like usually combines electrode materials such as gold, silver, platinum, copper, and nickel, which are electrode layers, with a relatively complicated manufacturing process, for example, vacuum deposition or vacuum sputtering and subsequent etching treatment. It is manufactured by forming a thin film (sensitive part) such as a polymer solid electrolyte or ceramics on the surface.
JP-A-11-281606 (Claims)

  When an electrochemical device is manufactured by the above manufacturing process, the manufacturing equipment is expensive and the manufacturing throughput is small, so that there is a problem in reducing the cost of the device. In addition, the characteristics of the functionally sensitive portion made of a solid polymer electrolyte, ceramics, and the like tend to vary depending on the film thickness and forming conditions, and there are many problems in achieving constant quality.

  An object of the present invention is to provide a novel sensor that can solve such a problem, and a polymer film having a novel property that can be used for such a sensor. Still other objects and advantages of the present invention will become apparent from the following description.

According to one embodiment of the present invention, at least a part or all of one surface of a conductive polymer film having a volume resistivity of 10 ⁻³ to 10 ⁵ Ω · cm is subjected to at least active energy ray irradiation treatment and chemical treatment. By providing either one, a polymer film in which the conductivity of the treated portion is lowered is provided.

  According to the aspect of the present invention, a novel polymer film in which the conductivity of the conductive polymer film is lowered can be obtained. Since this polymer film is easy to manufacture, it is easy to realize quality stabilization at low cost.

  The impedance of the treatment part is higher than the impedance of the non-treatment part, the polymer film is provided on an insulating substrate, and the polymer forming the conductive polymer film is polyaniline, polythiophene, polypyrrole , Polyfuran, polyacetylene, polyphenylene vinylene, polyparaphenylene or derivatives thereof, the active energy ray irradiation treatment is treatment with ultraviolet rays or electron beams, the chemical treatment is contact with an acidic substance, basic Including at least one treatment selected from the group consisting of contact with a substance, contact with an oxidizing agent, contact with a reducing agent, and contact with an organic substance, and the polymer film adsorbs the surface of the treated portion. An element capable of evaluating a substance from a change in conductivity of the treated portion, and the adsorbed substance It is moisture, is preferable.

  According to another aspect of the present invention, there is provided an environmental component evaluation sensor using the polymer film as an element for evaluating components in the surrounding environment. It is preferable that the environmental evaluation is an evaluation of humidity.

  According to the aspect of the present invention, a novel environmental component evaluation sensor can be obtained. Since it is easy to manufacture a polymer film used as an element, it is possible to reduce the cost and stabilize the quality of an environmental component evaluation sensor.

  ADVANTAGE OF THE INVENTION According to this invention, the novel polymer film which reduced the electroconductivity of a conductive polymer film and the novel environmental component evaluation sensor using this polymer film are provided. Since this polymer film is easy to manufacture, it is possible to reduce the cost and stabilize the quality of the environmental component evaluation sensor and its elements.

  Embodiments of the present invention will be described below with reference to the drawings, examples and the like. In addition, these figures, Examples, etc. and description illustrate the present invention, and do not limit the scope of the present invention. It goes without saying that other embodiments may belong to the category of the present invention as long as they match the gist of the present invention.

  It has been found that when at least one of active energy ray irradiation treatment and chemical treatment is applied to at least part or all of one surface of a conductive polymer film, the conductivity of the treated portion can be reduced. It was.

As the conductivity level of the conductive polymer film, when a conductive polymer film having a volume resistivity of 10 ⁻³ to 10 ⁵ Ω · cm is used, the conductivity of the treated portion is compared with the value of the non-treated portion. Can be quite low. Therefore, it is possible to use this low conductivity and its characteristics (for example, that the conductivity varies depending on the adsorbing substance) as an environmental component evaluation sensor as various electronic elements. Since this polymer film is easy to manufacture, it is possible to reduce the cost and stabilize the quality of the environmental component evaluation sensor and its elements.

  For example, if only a part of the conductive polymer film is processed and an unprocessed good conductive part is arranged across the processed part, the conductivity of the processed part can be measured. It can also be used as an element for a humidity sensor by detecting a change in conductivity due to adsorbed moisture.

  The conductive polymer forming the conductive polymer film may be any one as long as the above requirements are satisfied. Preferable examples include polythiophene derivatives such as polyaniline and poly-3,4-ethylenedioxythiophene (PEDOT), polypyrrole, polyfuran, polyacetylene, polyphenylene vinylene, polyparaphenylene and derivatives thereof. In particular, poly-3,4-ethylenedioxythiophene (PEDOT) and polyaniline that are stable in the air are suitable. A dopant-treated one may be used and is often preferable.

If the volume specific resistance of the conductive polymer film exceeds 10 ⁵ Ω · cm, the conductivity of the treated portion is too low and it tends to show simple insulation. In the case of less than 10 ⁻³ Ω · cm, it is often difficult to reduce the conductivity even by the above treatment.

  There is no restriction | limiting in particular about the method of forming the said conductive polymer film from these polymers, It can select from a well-known method. Specifically, spin coating, dip coating, roll coating, blade coating, die coating, spray coating, electrodeposition, chemical polymerization, electrochemical polymerization, gas phase polymerization, CVD (chemical) A wide range of manufacturing methods such as a chemical vapor deposition method) can be used. The film-like polymer may be crosslinked by some treatment.

  There is no restriction | limiting in particular also about the film thickness of the said conductive polymer film. When used as an element for a sensor, generally about 0.01 to 500 μm is preferable.

  The active energy ray irradiation treatment and the chemical treatment may be performed alone, or both may be performed simultaneously or before and after. Each may be performed multiple times. These treatments may be carried out on both sides of the conductive polymer film, but usually only one side is sufficient for applications utilizing the surface properties.

  In the above, the active energy ray means an electromagnetic wave having a wavelength shorter than that of ultraviolet rays, and examples thereof include ultraviolet rays, electron beams, X-rays and γ rays. As a result of irradiating the conductive polymer film, if the conductivity of the treated portion is reduced and other characteristics (for example, mechanical characteristics) are acceptable depending on the purpose of use, the active energy ray suitable for the present invention It can be said. Among these, ultraviolet rays or electron beams are practical and preferable in many cases. As ultraviolet rays, any of UV-A (wavelength 315 to 400 nm), UV-B (wavelength 280 to 315 nm), UV-C (wavelength 200 to 280 nm), and VUV (wavelength 10 to 200 nm) may be used.

  In the above, as chemical treatment, as a result of contacting the conductive polymer film with a chemical, the conductivity of the treated portion is lowered, and other characteristics (for example, mechanical characteristics) are acceptable depending on the purpose of use. It can be said that this is a chemical treatment suitable for the present invention. Examples of this treatment include contact with an acidic substance (for example, acid), contact with a basic substance (for example, alkali), contact with an oxidizing agent, contact with a reducing agent, and contact with an organic substance. These substances may be liquid or gaseous. A plurality of substances may be combined.

  The electrical conductivity of the treated portion may be lowered by any physical property evaluation. An increase in volume resistance value and an increase in impedance can be exemplified.

  There is no particular limitation on the degree of decrease in the conductivity of the processing portion, and an actually required level may be arbitrarily selected. Here, the decrease in conductivity can be known by comparing the treated portion with the non-treated portion. If there is no non-processed part, it may be compared with the value before processing. In the treatment according to the present invention, although the electronic conductivity of the conductive polymer is lowered, the ionic conductivity is often maintained, so that the increase in volume resistance and the increase in impedance are so-called insulators. In general, it does not rise as much as called. In this sense, it is preferable that the impedance of the processing portion is higher than the impedance of the non-processing portion because an element using the high impedance can be manufactured.

  The time required for the active energy ray treatment and chemical treatment can be determined according to the actually required level of decrease in conductivity. Note that it is often effective to increase the processing temperature in order to shorten the processing time.

  In many cases, the polymer film according to the present invention is preferably provided on an insulating substrate. If it does in this way, it will become easy to make a polymer film thinner, and it will become easy to guarantee mechanical strength with an insulating substrate.

  There are no particular restrictions on the insulating substrate, and many materials such as glass (quartz glass, borosilicate glass, soda glass, etc.), plastic, rubber, ceramics, and a silicon wafer with an oxide layer formed on the surface are used. obtain. In particular, plastics have good processability and are suitable for mass production, and thus greatly contribute to the cost reduction of elements. Types of plastic include polypropylene, polyethylene, polyvinyl chloride, polystyrene, acrylic resins such as polymethyl methacrylate and polyethyl methacrylate, polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthylate, polytetrafluoroethylene, Many materials such as fluororesin such as polyperfluoroalkyl, polyamide, polyimide, polyetheretherketone, polysulfone, polyoxymethylene, polyacrylonitrile-polybutadiene-polystyrene (ABS) are applicable. Moreover, as the form, various forms can be taken according to use requirements, such as plate shape, film shape, rod shape, rectangular parallelepiped, and spherical shape.

  The polymer film according to the present invention can be used as an element capable of evaluating the adsorbed substance on the surface of the treated portion from the change in conductivity of the treated portion. For example, it has been found that exposure to moisture (moisture) from the surrounding environment reduces the impedance of the treated portion. This is presumably because moisture was adsorbed on the surface of the treated portion.

  Such a change in conductivity due to the adsorption of the treated portion on the surface is considered to be valid not only for moisture but also for various substances. Therefore, if this property is utilized, the polymer film according to the present invention can also be used as an element for evaluating components in the surrounding environment. In the present invention, the components in the surrounding environment mean various substances such as moisture (moisture) and odorous components in the environment around the element. In the present invention, the environmental component evaluation sensor means that various substances such as moisture (moisture) and odor components in the environment around such an element are evaluated.

  Whether or not it is “adsorption” in the present invention does not require as a requirement of the present invention to confirm that some substance is actually adsorbed on the surface. If the conductivity of the treated portion changes when some substance coexists, it is sufficient to consider that “adsorption” according to the present invention has occurred. In addition, “evaluation” according to the present invention means to determine any of the amounts such as the presence / absence, type and concentration of the adsorbed substance. In other words, it means that one of the amounts such as the presence / absence, type and concentration of a specific component present in the environment around the element is determined. Here, the “specific component” cannot be generally described because it depends on what component the processing portion adsorbs. In general, moisture (moisture) may be sufficient for a specific component.

  If such a polymer film is used as an element, a sensor for evaluating a substance in the surrounding environment can be manufactured. For example, application to a humidity sensor, an odor sensor, etc. can be considered. That is, humidity and odor can be evaluated as environmental evaluation. Since the polymer film is easy to manufacture, such a sensor is expected to be inexpensive and stable in quality.

  Next, examples and comparative examples of the present invention will be described in detail.

[Example 1]
Hereinafter, an example of an element according to the present invention will be described with reference to the drawings. FIG. 1 is a structural example of an element according to the present invention (the lower diagram represents an AA cross section of the upper diagram (viewed from the upper side to the lower side of the paper)), and FIG. It is a figure which shows an example. In this example, a conductive polymer material was used as the electrode pattern.

  According to step S1 of FIG. 2, a soda lime glass plate (width 10 mm, length 25 mm, thickness 0.7 mm) was prepared as the insulating substrate 1 of FIG.

Next, according to step S2 of FIG. 2, the surface of the insulating substrate 1 is washed with alkali, and then a 0.7% by weight dispersion of poly-3,4-ethylenedioxythiophene (PEDOT) (manufactured by AGFA, Orgacon). S300-N2) was applied using a dip coater to form a liquid film having a coating thickness of 10 μm. This was heated and dried in a forced convection oven at 120 ° C. for 10 minutes to form a conductive polymer layer 21 having an average film thickness of 70 nm. The volume resistivity of this conductive polymer layer was 9 × 10 ⁻¹ Ω · cm.

Next, according to step S3 of FIG. 2, a perforated metal foil mask (made of SUS, thickness 50 μm) 22 of pattern 2 shown in FIG. 1 is pressed against the substrate, and nitrogen containing 1% by volume of oxygen is maintained while this state is maintained. Excimer UV light (wavelength: 172 nm, 30 mW / cm ² ) was irradiated for 100 seconds while being in contact with the atmosphere. The contact with ozone generated by excimer UV light corresponds to the chemical treatment according to the present invention.

  Thereafter, the mask was removed in accordance with Step S4 of FIG. 2, and a protective film 3 made of polyvinyl chloride resin was formed, whereby the device of Example 1 was obtained.

  After that, when the non-processed portions 4 and 5 on both sides of this element were used as lead wires, and the processed impedance that was not covered with the protective film 3 was measured as the humidity detector 6, the AC impedance was measured. It was shown that it can be used as a humidity sensor.

[Example 2]
A PET film (made by Toray Industries, Inc., thickness 188 μm) was used as the insulating substrate, the surface was activated by corona discharge, and then a polyaniline 5 wt% solution was applied using a bar coater, A liquid film was formed at 10 μm. This was heated and dried in a forced convection oven at 120 ° C. for 10 minutes to form a conductive polymer layer having an average film thickness of 500 nm. As a result of immersing this substrate in a 10% by weight aqueous solution of 2-naphthalenesulfonic acid for 30 minutes, the volume resistivity of this conductive polymer layer was 5 × 10 ⁻¹ Ω · cm.

  Next, a chrome-plated quartz plate is used as a photomask except for the pattern portion of 2 in FIG. 1, and this quartz photomask is brought into close contact with the substrate, and this state is maintained and an ultrahigh pressure mercury lamp light (wavelength 360 nm, 150W / cm) for 200 seconds. In this case, since the pattern portion is covered with the quartz plate, the chemical treatment according to the present invention was not performed.

  Thereafter, a protective film made of a polyvinyl chloride resin was formed, and the device of Example 2 was obtained.

  When the alternating current impedance with respect to the humidity of this element was measured, the response of FIG. 4 was shown, indicating that it could be used as a humidity sensor.

  In addition, the invention shown to the following additional remarks can be derived from the content disclosed above.

(Appendix 1)
At least one of the one side of the conductive polymer film having a volume resistivity of 10 ⁻³ to 10 ⁵ Ω · cm is subjected to at least one of active energy ray irradiation treatment and chemical treatment, and the treated portion. Polymer film with reduced conductivity.

(Appendix 2)
The polymer membrane according to appendix 1, wherein the impedance of the treated portion is higher than the impedance of the untreated portion.

(Appendix 3)
3. The polymer film according to appendix 1 or 2, provided on an insulating substrate.

(Appendix 4)
The polymer film according to any one of appendices 1 to 3, wherein the polymer that forms the conductive polymer film is polyaniline, polythiophene, polypyrrole, polyfuran, polyacetylene, polyphenylene vinylene, polyparaphenylene, or a derivative thereof.

(Appendix 5)
The polymer film according to any one of appendices 1 to 4, wherein the active energy ray irradiation treatment is treatment with ultraviolet rays or electron beams.

(Appendix 6)
The chemical treatment includes at least one treatment selected from the group consisting of contact with an acidic substance, contact with a basic substance, contact with an oxidizing agent, contact with a reducing agent, and contact with an organic substance. The polymer film in any one of 1-5.

(Appendix 7)
The polymer film according to any one of appendices 1 to 6, which is an element capable of evaluating an adsorbed substance on the surface of the treated portion from a change in conductivity of the treated portion.

(Appendix 8)
The polymer film according to appendix 7, wherein the adsorbing substance is moisture.

(Appendix 9)
An environmental component evaluation sensor using the polymer film according to any one of appendices 1 to 8 as an element for evaluating components in the surrounding environment.

(Appendix 10)
The environmental component evaluation sensor according to appendix 9, wherein the environmental evaluation is an evaluation of humidity.

It is a schematic diagram which shows the structural example of the element which concerns on this invention. It is a flowchart which shows an example of the manufacturing process of the element of FIG. It is a graph which shows the relationship between alternating current impedance and humidity. It is a graph which shows the relationship between alternating current impedance and humidity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulating base material 2 Pattern 3 Protective film 4 Non-processing part 5 Non-processing part 6 Humidity detection part 21 Conductive polymer layer 22 Mask

Claims (3)

In an environmental component evaluation sensor using a polymer film as an element for evaluating components in the surrounding environment,
The polymer membrane is
At least one of the one side of the conductive polymer film having a volume resistivity of 10 ⁻³ to 10 ⁵ Ω · cm is subjected to at least one of active energy ray irradiation treatment and chemical treatment, and the treated portion. lowering the conductivity, Ri Oh a polymer membrane impedance of the processing section is higher than the impedance of the untreated portions,
The components in the surrounding environment are evaluated by the treated portion of the polymer film.
Environmental component evaluation sensor.   The environmental component evaluation sensor according to claim 1, wherein the active energy ray irradiation treatment is treatment with ultraviolet rays or an electron beam.   The chemical treatment includes at least one treatment selected from the group consisting of contact with an acidic substance, contact with a basic substance, contact with an oxidizing agent, contact with a reducing agent, and contact with an organic substance. Item 3. The environmental component evaluation sensor according to Item 1 or 2.

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