WO2022014134A1 - Gas sensor member and production method thereof, gas sensor, gas detection method, and micro amount gas detection method - Google Patents

Gas sensor member and production method thereof, gas sensor, gas detection method, and micro amount gas detection method Download PDF

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Publication number
WO2022014134A1
WO2022014134A1 PCT/JP2021/018274 JP2021018274W WO2022014134A1 WO 2022014134 A1 WO2022014134 A1 WO 2022014134A1 JP 2021018274 W JP2021018274 W JP 2021018274W WO 2022014134 A1 WO2022014134 A1 WO 2022014134A1
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Prior art keywords
gas sensor
gas
sensor member
walled carbon
carbon nanotubes
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PCT/JP2021/018274
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French (fr)
Japanese (ja)
Inventor
克美 金子
プリティ アフジャ
サンジーブ クマール ウジェイン
壽雄 高城
恭 清水
克之 村田
Original Assignee
国立大学法人信州大学
株式会社寿ホールディングス
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Priority to JP2021562817A priority Critical patent/JP6996725B1/en
Publication of WO2022014134A1 publication Critical patent/WO2022014134A1/en

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    • 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
    • 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

Definitions

  • This disclosure relates to a gas sensor member and its manufacturing method, a gas sensor, a gas detection method, and a trace gas detection method.
  • Patent Document 1 describes a gas sensor using a single-walled carbon nanotube as a gas-sensitive material, and the single-walled carbon nanotube is a single-walled carbon nanotube obtained by firing a hydroxypropyl cellulose thin film containing the single-walled carbon nanotube.
  • a gas sensor characterized by using an aggregate of carbon nanotubes is disclosed.
  • single-walled carbon nanotubes are highly sensitive as a sensor member, they are strongly affected by changes in the surrounding environment, so the measurement results of the sensor may contain a lot of noise.
  • a means for further improving the sensitivity of the gas sensor member and reducing noise associated with the measurement are used for the measurement target.
  • a means for facilitating the detection of electrical changes associated with the adsorption of the gas can be considered.
  • a method of adjusting the conductivity of carbon nanotubes by encapsulating a conductor such as a metal in the carbon nanotubes and improving the sensitivity can be considered.
  • An object of the present disclosure is to provide a gas sensor member having excellent sensitivity and capable of reducing noise during measurement, and a method for manufacturing the gas sensor member.
  • An object of the present disclosure is also to provide a gas sensor having excellent sensitivity and capable of reducing noise during measurement. It is also an object of the present disclosure to provide a gas detection method having excellent sensitivity and reduced noise, and a trace gas detection method.
  • One aspect of the present disclosure comprises a substrate and a gas adsorption layer provided on the surface of the substrate, wherein the gas adsorption layer comprises a plurality of single-walled carbon nanotubes electrically connected to each other.
  • the single-walled carbon nanotubes provide a gas sensor member having an organic layer containing a conductive polymer on at least a part of the surface.
  • the gas sensor member has a gas adsorption layer containing a plurality of single-walled carbon nanotubes electrically connected to each other.
  • the single-walled carbon nanotube has an organic layer containing a conductive polymer on at least a part of the surface thereof.
  • the organic layer can reduce the influence on the single-walled carbon nanotubes due to changes in the external environment and suppress the generation of noise during measurement.
  • the organic layer contains a conductive polymer, changes in the external environment captured by the organic layer (for example, adsorption of gas molecules) can be transmitted to the single-walled carbon nanotubes, and sufficient measurement sensitivity as a sensor member must be maintained. Can be done. Due to such an action, the gas sensor member has excellent sensitivity and can reduce noise during measurement.
  • the organic layer may be provided on the outer surface of the single-walled carbon nanotube.
  • the base material may have elasticity. Since the base material has elasticity, the base material can be expanded and contracted. For example, by stretching the base material, it is possible to reduce the electrical contacts between the single-walled carbon nanotubes in the gas adsorption layer and increase the electrical resistance of the gas sensor member. Since such adjustment makes it possible to detect a trace amount of electrical change, the gas sensor member can be used for detecting a trace amount of gas.
  • the base material may be a porous base material.
  • gas can be passed through the base material, so that the gas sensor member can be installed in the flow path of the gas to be measured. Therefore, when the gas sensor member includes a porous substrate, the design range of the gas sensor can be further expanded. For example, it is also useful for miniaturization of gas sensors.
  • the shape of the base material may be plate-like.
  • the organic layer may be a monomolecular layer. Since the organic layer is a monomolecular layer, it is possible to more sufficiently suppress a decrease in sensitivity of the gas sensor member.
  • the conductive polymer may contain polyaniline.
  • the single-walled carbon nanotubes may have a polar functional group on the surface. Since the surface of the single-walled carbon nanotube has a polar functional group, the adhesion to the organic layer can be improved, and the durability of the gas sensor member can be improved.
  • the single-walled carbon nanotubes do not have to have openings.
  • the content of the conductive polymer may be 5% by mass or more based on the total mass of the single-walled carbon nanotubes.
  • the sensitivity can be further improved.
  • One aspect of the present disclosure provides a gas sensor comprising a gas sensor member and a sensor electrode electrically connected to the gas sensor member, wherein the gas sensor member is the gas sensor member.
  • the gas sensor Since the gas sensor is provided with the gas sensor member, it has excellent sensitivity and can reduce noise during measurement.
  • the gas sensor may further include a fixture for fixing the gas sensor member, and the fixture may have a means for deforming the gas sensor member.
  • the gas sensor member By equipping the gas sensor with the above-mentioned fixture, the gas sensor member can be deformed, and the electrical contact between the single-walled carbon nanotubes can be reduced to make adjustments such as increasing the electrical resistance of the gas sensor member. be.
  • the gas sensor has the above-mentioned means for deforming the gas sensor member, the gas sensor member can be deformed and the detection sensitivity can be adjusted according to the type and concentration of the gas to be detected.
  • One aspect of the present disclosure is a first step of forming an organic layer containing a conductive polymer on at least a part of the surface of the single-walled carbon nanotube, and a dispersion liquid containing the single-walled carbon nanotube provided with the organic layer.
  • Carbon nanotubes provide a method for manufacturing gas sensor members that are electrically connected to each other.
  • the method for manufacturing the gas sensor member can manufacture the gas sensor member as described above by including forming an organic layer containing a conductive polymer on at least a part of the surface of the single-walled carbon nanotube.
  • the first step is a step of forming the organic layer by polymerizing polyaniline on the surface of the single-walled carbon nanotubes in a solution containing the single-walled carbon nanotubes, aniline, and an oxidizing agent. It may be there.
  • the first step may be a step of forming the organic layer by adhering polyaniline on the surface of the single-walled carbon nanotubes in a solution containing the single-walled carbon nanotubes and polyaniline.
  • One aspect of the present disclosure includes a step of bringing a gas to be evaluated into contact with a gas sensor member, and provides a gas detection method in which the gas sensor member is the gas sensor member described above.
  • gas detection method uses the gas sensor member described above, gas detection with excellent sensitivity and reduced noise can be performed.
  • the gas detection method may be a method for detecting at least one gas selected from the group consisting of carbon dioxide, nitric oxide, sulfur disulfide, and sulfur trioxide.
  • One aspect of the present disclosure includes a step of deforming a gas sensor member and a step of bringing a gas to be evaluated into contact with the gas sensor member, wherein the gas sensor member is the above-mentioned gas sensor member, a trace gas detection method.
  • the gas sensor member is the above-mentioned gas sensor member, a trace gas detection method.
  • gas detection method uses the gas sensor member described above, gas detection with excellent sensitivity and reduced noise can be performed.
  • the trace gas detection method may be a method for detecting at least one gas selected from the group consisting of carbon dioxide, nitric oxide, sulfur disulfide, and sulfur trioxide.
  • a gas sensor member having excellent sensitivity and capable of reducing noise during measurement and a method for manufacturing the gas sensor member.
  • FIG. 1 is a schematic view showing a partial cross section of a gas sensor member.
  • FIG. 2 is a schematic view showing a partial end face of the gas sensor member.
  • FIG. 3 is a schematic diagram showing an example of a gas sensor.
  • FIG. 4 is a schematic diagram showing an example of a gas sensor.
  • FIG. 5 is a Raman spectrum of a single-walled carbon nanotube in which a monomolecular layer of polyaniline is formed on the outer surface.
  • FIG. 6 is an electron micrograph showing a part of the appearance of a single-walled carbon nanotube in which a monomolecular layer of polyaniline is formed on the outer surface.
  • FIG. 7 is a Raman spectrum of the gas sensor member.
  • FIG. 8 is an electron micrograph showing a part of the appearance of the gas sensor member.
  • FIG. 9 is a schematic view showing an evaluation device for a gas sensor member.
  • FIG. 10 is a graph showing the evaluation results of the cycle characteristics of the gas sensor member.
  • FIG. 11 is a graph showing the relationship between the sensor characteristics of the gas sensor member and the concentration of the gas to be detected.
  • FIG. 12 is a graph showing the relationship between the amount of deformation of the gas sensor member and the characteristics of the gas sensor.
  • FIG. 13 is a graph showing the relationship between the sensor characteristics of the gas sensor member and the concentration of the gas to be detected.
  • FIG. 14 is a graph showing the relationship between the sensor characteristics of the gas sensor member and the concentration of the gas to be detected.
  • FIG. 15 is a graph showing the relationship between the sensor characteristics of the gas sensor member and the type of gas to be detected.
  • each component in the composition means, when a plurality of substances corresponding to each component in the composition are present, the total amount of the plurality of substances present in the composition unless otherwise specified. ..
  • One embodiment of the gas sensor member has a base material and a gas adsorption layer provided on the surface of the base material.
  • the gas adsorption layer contains a plurality of single-walled carbon nanotubes electrically connected to each other.
  • the single-walled carbon nanotube has an organic layer on at least a part of the surface, and the organic layer contains a conductive polymer.
  • the gas adsorption layer may contain single-walled carbon nanotubes having no organic layer.
  • FIG. 1 is a schematic view showing a partial cross section of the gas sensor member.
  • the gas sensor member 100 has a base material 2 and a gas adsorption layer 4 provided on the surface of the base material 2.
  • the gas adsorption layer 4 contains a plurality of single-walled carbon nanotubes 6, and the single-walled carbon nanotubes 6 are electrically connected to each other.
  • the single-walled carbon nanotube 6 has an organic layer on at least a part of the surface (not shown).
  • the shape of the base material 2 is not particularly limited, and may be, for example, a plate shape, a block shape, or the like. When the base material 2 has a plate shape, it may be a sheet or a film depending on its thickness.
  • the base material 2 may be, for example, a uniform material having no pores, or may be a porous body or the like. It is preferable that the base material 2 is a porous body (that is, a porous base material) because the surface area of the gas adsorption layer 4 in the gas sensor member 100 can be further expanded.
  • FIG. 2 is a schematic view showing a partial end face of the gas sensor member when the base material 2 is a porous body. Since the gas sensor member 102 as shown in FIG.
  • the gas sensor member 102 can detect the gas sensor member because gas can permeate through the gas sensor member 102 itself. It can be installed in the gas flow path, etc., and the range of gas sensor design can be expanded.
  • the gas sensor member 102 shown in FIG. 2 is also useful for, for example, miniaturization of the gas sensor.
  • the base material 2 may be, for example, a base material having elasticity. Having elasticity means that it can be stretched by applying an external force based on the size of the base material in a state where no external force is applied, and shrinks to the standard size or a size close to the standard size when the external force is removed. It means that you can do it. It is preferable that the stretchable base material can be, for example, stretched 100% by applying an external force and then contracted to the initial shape with an error of about 1%.
  • the materials constituting the base material 2 are, for example, polydimethylsiloxane, polyurethane, styrene-butadiene rubber, butadiene rubber, chloroprene rubber, acrylonitrile-butadiene rubber, isoprene rubber, butyl rubber, ethylene / propylene rubber, acrylic rubber, hydrin rubber, and chloro. It may be sulfonated polyethylene or the like.
  • the material constituting the base material 2 may contain, for example, polydimethylsiloxane, or may be made of polydimethylsiloxane.
  • the gas adsorption layer 4 contains the single-walled carbon nanotubes 6, but may be made of, for example, the single-walled carbon nanotubes 6.
  • the gas adsorption layer 4 is a layer that can be energized in the in-plane direction by the single-walled carbon nanotubes 6 electrically connected to each other.
  • the gas adsorption layer 4 may have, for example, a mesh shape composed of single-walled carbon nanotubes 6.
  • the mesh shape can be said to be, for example, an electrical network structure composed of a plurality of single-walled carbon nanotubes 6.
  • Single-walled carbon nanotubes have an organic layer on at least part or all of the surface.
  • the surface of the single-walled carbon nanotube provided with the organic layer means at least the surface including the outer surface of the single-walled carbon nanotube, and preferably only the outer surface of the single-walled carbon nanotube.
  • the organic layer may be provided on the outer surface of the single-walled carbon nanotubes, or may be provided only on the outer surface of the single-walled carbon nanotubes.
  • the organic layer may be composed of a plurality of layers including a conductive polymer, or may be a monomolecular layer.
  • the monomolecular layer may be a layer composed of only a conductive polymer.
  • the conductive polymer contained in the organic layer may be a conductive polymer capable of adsorbing gas molecules to be measured and transferring electrons to and from single-walled carbon nanotubes.
  • the conductive polymer may be, for example, a conductive polymer having a hole transporting ability.
  • the conductive polymer may be, for example, an aromatic conductive polymer.
  • the conductive polymer can be appropriately selected depending on the type of gas to be measured and the like.
  • the conductive polymer contains, for example, polyaniline, polyriophene, polypyrrole, polyparaphenylene, polyphenylene vinylene, polyphenylene sulfide and the like, preferably containing polyaniline, and more preferably polyaniline.
  • the single-walled carbon nanotube may have, for example, a polar functional group on the surface and a polar functional group on the outer surface. Since the single-walled carbon nanotubes have a polar functional group on the surface, the adhesion to the organic layer can be improved. By improving the adhesion between the organic layer and the surface of the single-walled carbon nanotubes, it is possible to more reliably transmit changes in the chemical environment of the organic layer due to gas adsorption to the carbon nanotubes, further reducing sensitivity. It can be suppressed.
  • the polar functional group include a hydroxyl group, a carbonyl group, a carboxy group and the like.
  • the single-walled carbon nanotubes have few defects and do not have to have openings.
  • the lower limit of the content of the conductive polymer may be, for example, 5% by mass or more, 10% by mass or more, or 30% by mass or more, based on the total mass of the single-walled carbon nanotubes.
  • the upper limit of the content of the conductive polymer may be, for example, 60% by mass or less, 50% by mass or less, or 40% by mass or less based on the total mass of the single-walled carbon nanotubes.
  • the content of the conductive polymer may be adjusted within the above range, and based on the total mass of the single-walled carbon nanotubes, for example, 5 to 60% by mass, 10 to 50% by mass, or 30 to 40% by mass. May be%.
  • the gas sensor member as described above can be manufactured by, for example, the following method.
  • One embodiment of the method for manufacturing a gas sensor member includes a first step of forming an organic layer containing a conductive polymer on at least a part of the surface of a single-walled carbon nanotube (hereinafter, also referred to as an organic layer forming step) and an organic layer.
  • a second step (a second step) in which a dispersion liquid containing the single-walled carbon nanotubes provided with the above-mentioned material is prepared, and the dispersion liquid is brought into contact with the base material to provide a gas adsorption layer containing the single-walled carbon nanotubes on the base material.
  • a gas adsorption layer forming step it is also referred to as a gas adsorption layer forming step.
  • the single-walled carbon nanotube As the single-walled carbon nanotube, a commercially available one may be used, or a separately prepared one may be used. When preparing single-walled carbon nanotubes, for example, an arc discharge method, a laser vapor deposition method, a chemical vapor deposition method, or the like can be used.
  • the gas adsorption layer contains a plurality of single-walled carbon nanotubes, even if the performance of each single-walled carbon nanotube varies slightly, it can be used.
  • the single-walled carbon nanotubes any of zigzag-type single-walled carbon nanotubes, chiral-type single-walled carbon nanotubes, and armchair-type single-walled carbon nanotubes can be used.
  • zigzag type single-walled carbon nanotubes and chiral type single-walled carbon nanotubes Preferably zigzag type single-walled carbon nanotubes and chiral type single-walled carbon nanotubes.
  • the chiral angle is not particularly limited and may be appropriately adjusted according to the desired electrical characteristics.
  • the diameter of the single-walled carbon nanotubes may be, for example, 0.5 to 5.0 nm, 0.5 to 4.0 nm, or 0.4 to 1.0 nm.
  • the length of the single-walled carbon nanotubes may be, for example, 10 to 5000000 nm, 20 to 2000000 nm, or 100 to 1000000 nm.
  • the single-walled carbon nanotube may have a polar functional group on the surface. Since the surface of the single-walled carbon nanotube has a polar functional group, the adhesion to the organic layer can be improved, and the durability of the gas sensor member can be improved.
  • a polar functional group may be introduced into the surface of the single-walled carbon nanotube by an oxidation treatment or the like. Examples of the polar functional group include a hydroxyl group, a carbonyl group, a carboxy group and the like.
  • the method for manufacturing a gas sensor member may further include a step of oxidizing the single-walled carbon nanotubes before the first step.
  • the conditions of the oxidation treatment can be selected from the viewpoint of suppressing the combustion of the single-walled carbon nanotubes and suppressing the formation of openings on the surface of the single-walled carbon nanotubes.
  • the oxidation treatment step can be performed in an atmosphere containing oxygen, preferably in air.
  • the upper limit of the heat treatment temperature in the oxidation treatment step may be, for example, 350 ° C. or lower, 300 ° C. or lower, or 200 ° C. or lower.
  • the upper limit of the heat treatment temperature in the oxidation treatment step may be, for example, 150 ° C. or higher, 170 ° C. or higher, or 180 ° C. or higher.
  • the polar functional group can be efficiently introduced into the surface of the single-walled carbon nanotube.
  • the temperature of the heat treatment in the oxidation treatment step may be adjusted within the above range, and may be, for example, 150 to 350 ° C., 170 to 300 ° C., or 180 to 200 ° C.
  • the heat treatment time in the oxidation treatment step may be, for example, 0.1 to 15 hours, 0.1 to 5 hours, 0.5 to 5 hours, 1 to 5 hours, or 1 to 3 hours.
  • an organic layer containing a conductive polymer is formed on at least a part of the surface of the single-walled carbon nanotube.
  • the method for forming the organic layer include a method of forming an organic layer by polymerizing a monomer that gives a conductive polymer on the surface of a single-walled carbon nanotube, and a method of forming a conductive polymer that has been synthesized in advance. It may be a method of forming an organic layer by adhering it on the surface of the layered carbon nanotube.
  • the organic layer forming step is preferably a method of forming an organic layer by polymerizing a monomer that gives a conductive polymer on the surface of the single-walled carbon nanotube. Further, depending on the molecular weight of the conductive polymer and the like, the solubility may be low and it may be difficult to prepare a solution and a dispersion. In such a case, a means including polymerizing a monomer can be used.
  • the organic layer forming step is carried out in a solution containing, for example, a single-walled carbon nanotube, aniline, and an oxidizing agent, in the above-mentioned single-walled carbon nanotube. It may be a step of forming the organic layer by polymerizing polyaniline on the surface, and the polyaniline is adhered on the surface of the single-walled carbon nanotube in a solution containing the single-walled carbon nanotube and the polyaniline. This may be a step of forming the organic layer.
  • the solution containing the single-walled carbon nanotubes, aniline, and an oxidizing agent, and the solution containing the single-walled carbon nanotubes and polyaniline may be, for example, a dispersion.
  • the dispersion medium include water and a mixed medium of water and an organic solvent.
  • Examples of the oxidizing agent used for polymerizing polyaniline include ammonium persulfate, sodium persulfate, and potassium persulfate.
  • a dispersion liquid containing the single-walled carbon nanotubes provided with an organic layer is prepared, and the dispersion liquid is brought into contact with the base material to contain the single-walled carbon nanotubes on the base material.
  • a gas adsorption layer is provided.
  • the base material to which the dispersion liquid is brought into contact those exemplified as the base material constituting the above-mentioned gas sensor member can be used.
  • Examples of the dispersion medium for preparing the dispersion liquid containing the single-walled carbon nanotubes provided with the organic layer include water and a mixed medium of water and an organic solvent.
  • As the water for example, ion-exchanged water or the like can be used.
  • a dispersant may be used to disperse the single-walled carbon nanotubes.
  • the dispersant include Zn-Al dispersants and sodium lauryl sulfate.
  • the Zn-Al dispersant is a complex based on zinc (Zn) and aluminum (Al).
  • the Zn-Al dispersant can be prepared, for example, by sol-gel synthesis in which a solution prepared by dissolving 1 g each of zinc acetate and aluminum nitrate in 20 g of pure water is refluxed at a temperature of 373 K for 2 hours. ..
  • the Zn-Al complex does not adhere to the surface of the single-walled carbon nanotubes, it is suitably used because it does not form a coating layer on the surface of the organic layer while promoting good dispersion of the single-walled carbon nanotubes.
  • the dispersion may be prepared, for example, by sonicating a mixture of single-walled carbon nanotubes, a dispersant and a dispersion medium.
  • the sonication time may be, for example, 30 minutes or longer, or 60 minutes or longer.
  • the method of bringing the dispersion liquid into contact with the base material may be, for example, a method of immersing the base material in the dispersion liquid, or a method of dropping or spraying the dispersion liquid on the base material.
  • heat treatment or the like may be performed as necessary.
  • the concentration of the dispersion medium in the liquid film may be reduced by heat treatment.
  • the temperature of the heat treatment may be, for example, 80 to 120 ° C. or 90 to 100 ° C. From the viewpoint of facilitating the reduction of the dispersion medium, the above heat treatment can also be performed in a reduced pressure environment.
  • the dispersant may remain in the gas sensor member obtained by forming the gas adsorption layer on the base material. From the viewpoint of reducing the residual amount of the dispersant, for example, cleaning with an acid may be performed.
  • the acid for example, dilute nitric acid or the like can be used.
  • the above-mentioned gas sensor member can be used as a constituent member of the gas sensor.
  • One embodiment of the gas sensor includes a gas sensor member and a sensor electrode electrically connected to the gas sensor member.
  • FIG. 3 is a schematic diagram showing an example of a gas sensor.
  • the gas sensor 200 includes a support 40, a gas sensor member 100 provided on the support 40, and a sensor electrode 50 electrically connected to the gas sensor member 100.
  • the gas sensor 200 can detect the gas in the environment to which the gas sensor member 100 is exposed by detecting the change in the electric resistance in the gas sensor member 100 via the sensor electrode 50.
  • the support 40 is not particularly limited, and may be, for example, a glass base material, a ceramic base material, a resin base material, or the like.
  • a stretchable base material may be used.
  • the sensor electrode 50 may be, for example, an electrode made of a metal such as gold, platinum, silver, copper, aluminum, nickel, and chromium, and is preferably an electrode made of gold, platinum, and copper.
  • the gas sensor may further include a fixture for fixing the gas sensor member, and the fixture may have a means for deforming the gas sensor member.
  • the fixture may have, for example, a support member for fixing an end portion of the gas sensor member and a pressing member capable of deforming the gas sensor member by applying tension to the gas sensor member.
  • the shapes of the support member and the pressing member are not particularly limited.
  • FIG. 4 is a schematic diagram showing an example of a gas sensor, and shows an example having an example of a fixture as described above.
  • the gas sensor 202 includes a sheet-shaped gas sensor member 102, a sensor electrode 50 electrically connected to the gas sensor member 102, and a fixture 80 capable of deforming the gas sensor member 102.
  • the fixture 80 includes a support member 60 having a through hole 70A for passing a gas to be measured, and a pressing member 70 having a through hole 60A capable of accommodating the support member 60.
  • the support member 60 has a cylindrical main body portion 62 and a flange portion 64.
  • the pressing member 70 has a cylindrical main body portion 72 and a flange portion 74.
  • the inner diameter of the cylindrical main body 62 of the support member 60 is larger than the outer diameter of the tubular main body 72 of the pressing member 70, and the tubular main body 72 of the pressing member 70 is housed in the main body 62 of the support member 60. can do.
  • the sheet-shaped gas sensor member 102 is pressed against the gas sensor member 102 so that the main body 72 of the pressing member 70 is accommodated in the main body 62 of the support member 60.
  • Tension can be applied to stretch at the desired magnification.
  • the surface of the flange portion 64 on the gas sensor member 102 side of the support member 60 may be processed so as to prevent the gas sensor member 102 from slipping.
  • FIG. 4 shows an example in which both the support member 60 and the pressing member 70 have a flange portion, but the support member 60 and the pressing member 70 may not have a flange portion.
  • the support member 60 and the pressing member 70 have a flange portion, adjustment when pressing and deforming the sheet-shaped gas sensor member 102 becomes easier.
  • the above-mentioned gas sensor member is useful for gas detection because it has excellent sensitivity and can reduce noise in measurement.
  • One embodiment of the gas detection method includes a step of bringing a gas to be evaluated into contact with a gas sensor member.
  • the gas to be evaluated may be, for example, at least one gas selected from the group consisting of carbon dioxide, nitric oxide, sulfur disulfide, and sulfur trioxide. That is, the gas detection method may be a method for detecting at least one gas selected from the group consisting of carbon dioxide, nitric oxide, sulfur disulfide, and sulfur trioxide.
  • One embodiment of the method for detecting a trace gas includes a step of deforming a gas sensor member and a step of bringing the gas sensor member into contact with a gas to be evaluated.
  • the gas sensor member may be deformed according to the concentration of the gas to be detected and the like. For example, by deforming the gas sensor member so that it can be detected when the concentration of the gas to be measured exceeds a certain level and adjusting the resistance value, it can be used to detect the leakage of the target gas.
  • the detection sensitivity in the above-mentioned gas detection method and trace gas detection method is, for example, based on the volume of the gas molecule to be measured in the standard state of the mixed gas (for example, the atmosphere) containing the gas molecule to be measured. It is a sensitivity that can be detected even if it is 10 ppm or less.
  • the detection sensitivity in the above-mentioned gas detection method and trace gas detection method can be adjusted by deforming the above-mentioned gas sensor member, and the concentration of the gas molecule to be measured is a mixed gas containing the gas molecule to be measured ( For example, it may be 0.1 ppm or less, 1 ppm or less, 2 ppm or less, or 5 ppm or less based on the volume in the standard state of (atmosphere).
  • Example 1 [Organic layer forming process] A polar functional group was introduced by subjecting a single-walled carbon nanotube (manufactured by Meijo Carbon Co., Ltd., trade name: EC1.0) to an oxidation treatment in the air at 250 ° C. for 10 minutes. 45 mg of the oxidized single-walled carbon nanotubes, 10 mL (10.2 mg) of aniline, and 50 mL of hydrochloric acid (concentration: 0.1 mol / L) are measured in a container and subjected to ultrasonic treatment for 30 minutes to disperse the dispersion. Was prepared.
  • a single-walled carbon nanotube manufactured by Meijo Carbon Co., Ltd., trade name: EC1.0
  • the solid matter in the dispersion was recovered by filtration and washed with ion-exchanged water. After washing with ion-exchanged water, the solid matter was further washed with ethanol, and then vacuum dried to prepare single-walled carbon nanotubes having a monomolecular layer of polyaniline on the outer surface. It was confirmed by Raman spectrum and electron microscopic observation that the organic layer was formed on the outer surface of the obtained single-walled carbon nanotubes.
  • FIG. 5 shows a Raman spectrum
  • FIG. 6 shows an electron micrograph.
  • a porous substrate made of polydimethylsiloxane was prepared based on the sugar templates method. First, sugar powder was compacted and molded into a block to prepare a mold. In this mold, a silicone elastomer (manufactured by DuPont Toray Specialty Material Co., Ltd., trade name: silpot184) and a catalyst for silicone resin as a curing agent (manufactured by DuPont Toray Specialty Material Co., Ltd., trade name: silpot184cat) are used. However, the mixed solution was impregnated so as to have a mass ratio of 10: 1.
  • the silicone elastomer was solidified by heating to 45 ° C. and treating at the temperature for 5 hours. Then, the whole mold composed of sugar was placed in ion-exchanged water and subjected to ultrasonic treatment while heating at 60 ° C. to dissolve and remove the sugar to prepare a porous substrate made of polydimethylsiloxane. ..
  • the shape of the gas sensor member was 3 cm in length, 1 cm in width, and 0.2 cm in thickness according to the shape of the porous base material. It was confirmed by Raman spectrum and electron microscope observation that the gas adsorption layer containing the above-mentioned single-walled carbon nanotubes was formed on the surface of the porous substrate.
  • FIG. 7 shows a Raman spectrum
  • FIG. 8 shows an electron micrograph.
  • the Raman spectrum of the member obtained by the above operation is relative to the Raman spectrum of the porous substrate (spectrum shown by Porous PDMS in FIG. 7).
  • a G band derived from single-walled carbon nanotubes and a peak in the wavenumber range around 2800 to 3000 cm -1 derived from polydimethylsiloxane are observed, and 1000 to 1500 cm derived from polyaniline.
  • a peak in the wavenumber region of -1 was observed, and it was confirmed that the desired gas adsorption layer was formed on the porous substrate.
  • the surface of the member obtained by the above operation is the surface of the porous substrate (photograph shown in FIG. 8A). Can confirm the fibrous material that was not observed, which supports the measurement result of FIG. 7.
  • Cycle characteristics The performance of the gas sensor member obtained as described above was evaluated. Specifically, an evaluation device (gas sensor) for a gas sensor member as shown in FIG. 9 was configured, and the response to carbon dioxide gas (carbon dioxide) was evaluated.
  • the gas sensor 300 shown in FIG. 9 supplies sample gas from the supply line Li (Line in) to the gas sensor member 104 in a state where the gas sensor member 104 is sandwiched and fixed by the support members 66 and 76 having an opening in the center, and is discharged. The sample gas that has passed through the gas sensor member 104 is discharged from the line Lo (Line out).
  • a change in the electrical state (change in resistance value) of the gas sensor member that occurs when the sample gas is supplied was observed by an ammeter via the sensor electrode 50 electrically connected to the gas sensor member 104.
  • the gas supplied from the supply line Li is connected to an air cylinder and a carbon dioxide gas cylinder, and the mixing ratio of air and carbon dioxide gas is set to be adjustable.
  • Performance was evaluated by supplying the gas sensor member with the mixed gas adjusted so that the concentration of carbon dioxide gas was 5 ppm based on the volume of the mixed gas in the standard state. The measurement was performed in an environment of 25 ° C., and the resistance value was measured by setting the voltage to 1 V. For comparison, a member in which a gas adsorption layer containing a single-walled carbon nanotube into which a polar functional group was introduced was formed on a porous substrate without forming a monomolecular layer of polyaniline was prepared, and the same as in Example 1. Was evaluated. The results are shown in FIG.
  • the gas sensor member manufactured by using the single-walled carbon nanotube on which the polyaniline single-walled layer is formed is the gas sensor member manufactured by using the single-walled carbon nanotube without the polyaniline single-walled layer.
  • the value of Response on the vertical axis rises well following the start of supply of the mixed gas.
  • the maximum value of Response on the vertical axis was manufactured using the single-walled carbon nanotubes without the polyaniline single-walled layer. It was confirmed that the sensitivity was larger than the maximum value of Response on the vertical axis in the measurement result of the gas sensor member and had about twice the sensitivity. It can also be confirmed from the shape of the graph that noise is suppressed.
  • the gas sensor member prepared in Example 1 detects carbon dioxide gas in the same manner as the first supply even if the mixed gas is supplied a plurality of times, and the mixed gas is supplied. It is initialized after shutting off. Therefore, the gas sensor member of the first embodiment can also be used for a plurality of times of sensing.
  • the decrease in resistance value can be confirmed by the adsorption of carbon dioxide gas, and it is sufficient even when the concentration of the gas to be detected is relatively low. It was confirmed that it could be detected.
  • the response was improved by increasing the amount of deformation of the gas sensor member. That is, it was confirmed that the sensitivity can be further increased by deforming the gas sensor member, and detection can be performed by deforming the gas sensor member, for example, when the concentration of the detection target gas is small.
  • a gas sensor member having excellent sensitivity and capable of reducing noise during measurement and a method for manufacturing the gas sensor member.

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Abstract

One aspect of the present disclosure provides a gas sensor member that comprises a base material and a gas adsorption layer provided on the surface of the base material. The gas adsorption layer includes a plurality of single-wall carbon nanotubes that are mutually electrically connected. The single-wall carbon nanotubes include, at least in a portion of the surface thereof, an organic layer that contains an electroconductive polymer.

Description

ガスセンサ部材及びその製造方法、ガスセンサ、ガス検知方法、並びに、微量ガス検知方法Gas sensor member and its manufacturing method, gas sensor, gas detection method, and trace gas detection method
　本開示は、ガスセンサ部材及びその製造方法、ガスセンサ、ガス検知方法、並びに、微量ガス検知方法に関する。 This disclosure relates to a gas sensor member and its manufacturing method, a gas sensor, a gas detection method, and a trace gas detection method.
　単層カーボンナノチューブはその構成元素であるすべての炭素がチューブの表面に存在しているため、外部の化学的な環境の変化によって、単層カーボンナノチューブ自体の物性が大きく変化することが知られている。例えば、単層カーボンナノチューブの表面に極微量の気体分子が吸着することによって、単層カーボンナノチューブの電気抵抗が増減することが知られている。このような知見を応用して、単層カーボンナノチューブが示す電気的な挙動に基づいて気体分子を検知するガス検知方法の研究、及び単層カーボンナノチューブを用いたガスセンサ部材の研究等がなされている。 Since all carbon, which is a constituent element of single-walled carbon nanotubes, is present on the surface of the tube, it is known that the physical properties of single-walled carbon nanotubes themselves change significantly due to changes in the external chemical environment. There is. For example, it is known that the electrical resistance of single-walled carbon nanotubes increases or decreases due to the adsorption of a very small amount of gas molecules on the surface of single-walled carbon nanotubes. Applying such findings, research is being conducted on gas detection methods that detect gas molecules based on the electrical behavior exhibited by single-walled carbon nanotubes, and research on gas sensor members using single-walled carbon nanotubes. ..
　例えば、特許文献１には、単層カーボンナノチューブを感ガス材料とするガスセンサであって、該単層カーボンナノチューブとして、単層カーボンナノチューブを含有するヒドロキシプロピルセルロース薄膜を焼成処理して得られる単層カーボンナノチューブ集合体を用いたことを特徴とするガスセンサが開示されている。 For example, Patent Document 1 describes a gas sensor using a single-walled carbon nanotube as a gas-sensitive material, and the single-walled carbon nanotube is a single-walled carbon nanotube obtained by firing a hydroxypropyl cellulose thin film containing the single-walled carbon nanotube. A gas sensor characterized by using an aggregate of carbon nanotubes is disclosed.
特開２００８－１８５４９５号公報Japanese Unexamined Patent Publication No. 2008-185495 特開２００３－２２７８０６号公報Japanese Unexamined Patent Publication No. 2003-227806
　単層カーボンナノチューブはセンサ部材として高感度である一方で、周囲の環境変化の影響を強く受けるため、センサの測定結果に多くのノイズが含まれ得る。単層カーボンナノチューブをガスセンサ部材として用い、測定対象となる気体分子の検出能を向上させるためには、例えば、ガスセンサ部材の感度をより向上させる手段、及び測定に伴うノイズを低減して、測定対象の吸着に伴う電気的な変化を検出しやすくする手段等が考えられる。前者の手段としては、カーボンナノチューブに金属等の導電体を内包させることでカーボンナノチューブの導電性を調製し、感度を向上させる方法が考えられる。しかし、導電体を内包させる過程でカーボンナノチューブ自体に欠陥等が生じ得る。また、後者の手段としては、多層カーボンナノチューブを用いる方法が考えられる（例えば、特許文献２等）。しかし、多層カーボンナノチューブは単層カーボンナノチューブに比べて結晶性が高く、変形を伴うような部材に使用する場合には部材としての脆さが懸念される。 While single-walled carbon nanotubes are highly sensitive as a sensor member, they are strongly affected by changes in the surrounding environment, so the measurement results of the sensor may contain a lot of noise. In order to improve the detectability of gas molecules to be measured by using single-walled carbon nanotubes as a gas sensor member, for example, a means for further improving the sensitivity of the gas sensor member and reducing noise associated with the measurement are used for the measurement target. A means for facilitating the detection of electrical changes associated with the adsorption of the gas can be considered. As the former means, a method of adjusting the conductivity of carbon nanotubes by encapsulating a conductor such as a metal in the carbon nanotubes and improving the sensitivity can be considered. However, defects may occur in the carbon nanotubes themselves in the process of encapsulating the conductor. Further, as the latter means, a method using multi-walled carbon nanotubes can be considered (for example, Patent Document 2 and the like). However, the multi-walled carbon nanotubes have higher crystallinity than the single-walled carbon nanotubes, and there is a concern about brittleness as a member when used for a member accompanied by deformation.
　本開示の目的は、感度に優れ、測定の際のノイズの低減が可能なガスセンサ部材、及びその製造方法を提供することである。本開示の目的はまた、感度に優れ、測定の際のノイズの低減が可能なガスセンサを提供することである。本開示の目的はまた、感度に優れ、ノイズが低減されたガス検知方法、及び微量ガス検知方法を提供することである。 An object of the present disclosure is to provide a gas sensor member having excellent sensitivity and capable of reducing noise during measurement, and a method for manufacturing the gas sensor member. An object of the present disclosure is also to provide a gas sensor having excellent sensitivity and capable of reducing noise during measurement. It is also an object of the present disclosure to provide a gas detection method having excellent sensitivity and reduced noise, and a trace gas detection method.
　本開示の一側面は、基材と、上記基材の表面上に設けられたガス吸着層と、を有し、上記ガス吸着層は、互いに電気的に接続された複数の単層カーボンナノチューブを含み、上記単層カーボンナノチューブは表面の少なくとも一部に、導電性高分子を含む有機層を有する、ガスセンサ部材を提供する。 One aspect of the present disclosure comprises a substrate and a gas adsorption layer provided on the surface of the substrate, wherein the gas adsorption layer comprises a plurality of single-walled carbon nanotubes electrically connected to each other. Including, the single-walled carbon nanotubes provide a gas sensor member having an organic layer containing a conductive polymer on at least a part of the surface.
　上記ガスセンサ部材は、互いに電気的に接続された複数の単層カーボンナノチューブを含むガス吸着層を有する。当該単層カーボンナノチューブは、表面の少なくとも一部に導電性高分子を含む有機層を有している。当該有機層は外部環境の変化による単層カーボンナノチューブへの影響を低減し、測定の際のノイズの発生を抑制することができる。また、有機層が導電性高分子を含むため、有機層が捉える外部環境の変化（例えば、気体分子の吸着等）を単層カーボンナノチューブへ伝達でき、センサ部材として十分な測定感度も維持することができる。このような作用によって、上記ガスセンサ部材は、感度に優れ、測定の際のノイズの低減も可能となっている。 The gas sensor member has a gas adsorption layer containing a plurality of single-walled carbon nanotubes electrically connected to each other. The single-walled carbon nanotube has an organic layer containing a conductive polymer on at least a part of the surface thereof. The organic layer can reduce the influence on the single-walled carbon nanotubes due to changes in the external environment and suppress the generation of noise during measurement. In addition, since the organic layer contains a conductive polymer, changes in the external environment captured by the organic layer (for example, adsorption of gas molecules) can be transmitted to the single-walled carbon nanotubes, and sufficient measurement sensitivity as a sensor member must be maintained. Can be done. Due to such an action, the gas sensor member has excellent sensitivity and can reduce noise during measurement.
　上記有機層が前記単層カーボンナノチューブの外側表面に設けられていてよい。導電性高分子を含む有機層が検知対象となるガスとより接触しやすい単層カーボンナノチューブの外側表面に設けられていることによって、外部環境の変化による単層カーボンナノチューブへの影響をより一層抑制することができ、ガスセンサ部材としての感度とノイズの低減とを高い水準で両立することができる。 The organic layer may be provided on the outer surface of the single-walled carbon nanotube. By providing an organic layer containing a conductive polymer on the outer surface of the single-walled carbon nanotubes that are more likely to come into contact with the gas to be detected, the influence of changes in the external environment on the single-walled carbon nanotubes is further suppressed. It is possible to achieve both sensitivity as a gas sensor member and reduction of noise at a high level.
　上記基材は伸縮性を有してよい。基材が伸縮性を有することによって、基材の伸縮が可能となる。例えば、基材を伸張させることで、ガス吸着層内における単層カーボンナノチューブ同士の電気的な接点を減じ、ガスセンサ部材の電気抵抗を上昇させるなどの調整が可能となる。このような調整によって、より微量な電気的な変化を検出可能となることから、上記ガスセンサ部材を微量ガスの検知に使用することができる。 The base material may have elasticity. Since the base material has elasticity, the base material can be expanded and contracted. For example, by stretching the base material, it is possible to reduce the electrical contacts between the single-walled carbon nanotubes in the gas adsorption layer and increase the electrical resistance of the gas sensor member. Since such adjustment makes it possible to detect a trace amount of electrical change, the gas sensor member can be used for detecting a trace amount of gas.
　上記基材は多孔質基材であってよい。基材が多孔質基材である場合、ガスを通過させることもできるため、上記ガスセンサ部材を測定対象となるガスの流路中に設置することができる。よって、ガスセンサ部材が多孔質基材を備える場合、ガスセンサの設計の幅をより広げることができる。例えば、ガスセンサの小型化等にも有用である。 The base material may be a porous base material. When the base material is a porous base material, gas can be passed through the base material, so that the gas sensor member can be installed in the flow path of the gas to be measured. Therefore, when the gas sensor member includes a porous substrate, the design range of the gas sensor can be further expanded. For example, it is also useful for miniaturization of gas sensors.
　上記基材の形状は板状であってよい。 The shape of the base material may be plate-like.
　上記有機層は単分子層であってよい。有機層が単分子層であることによって、ガスセンサ部材の感度の低下をより十分に抑制できる。 The organic layer may be a monomolecular layer. Since the organic layer is a monomolecular layer, it is possible to more sufficiently suppress a decrease in sensitivity of the gas sensor member.
　上記導電性高分子はポリアニリンを含有してよい。 The conductive polymer may contain polyaniline.
　上記単層カーボンナノチューブは表面に極性官能基を有してよい。単層カーボンナノチューブの表面が極性官能基を有することで、有機層との密着性を向上させることができ、ガスセンサ部材の耐久性を向上できる。 The single-walled carbon nanotubes may have a polar functional group on the surface. Since the surface of the single-walled carbon nanotube has a polar functional group, the adhesion to the organic layer can be improved, and the durability of the gas sensor member can be improved.
　上記単層カーボンナノチューブは開口を有しなくてよい。 The single-walled carbon nanotubes do not have to have openings.
　上記導電性高分子の含有量が、上記単層カーボンナノチューブの全質量を基準として、５質量％以上であってよい。導電性高分子の含有量が単層カーボンナノチューブに対して所定量以上であることによって、感度をより向上させることができる。 The content of the conductive polymer may be 5% by mass or more based on the total mass of the single-walled carbon nanotubes. When the content of the conductive polymer is a predetermined amount or more with respect to the single-walled carbon nanotubes, the sensitivity can be further improved.
　本開示の一側面は、ガスセンサ部材と、上記ガスセンサ部材と電気的に接続されたセンサ電極と、を備え、上記ガスセンサ部材が上述のガスセンサ部材である、ガスセンサを提供する。 One aspect of the present disclosure provides a gas sensor comprising a gas sensor member and a sensor electrode electrically connected to the gas sensor member, wherein the gas sensor member is the gas sensor member.
　上記ガスセンサは、上述のガスセンサ部材を備えることから、感度に優れ、測定の際のノイズの低減が可能である。 Since the gas sensor is provided with the gas sensor member, it has excellent sensitivity and can reduce noise during measurement.
　上記ガスセンサは上記ガスセンサ部材を固定する固定具を更に備えてよく、上記固定具が上記ガスセンサ部材を変形させる手段を有していてもよい。ガスセンサが上述のような固定具を備えることによって、ガスセンサ部材を変形させることができ、単層カーボンナノチューブ同士の電気的な接点を減じて、ガスセンサ部材の電気抵抗を上昇させるなどの調整が可能である。ガスセンサが上記ガスセンサ部材を変形させる上述のような手段を有することで、検知対象となるガスの種類及び濃度等に合わせて、ガスセンサ部材を変形させ、検知の感度を調整することもできる。 The gas sensor may further include a fixture for fixing the gas sensor member, and the fixture may have a means for deforming the gas sensor member. By equipping the gas sensor with the above-mentioned fixture, the gas sensor member can be deformed, and the electrical contact between the single-walled carbon nanotubes can be reduced to make adjustments such as increasing the electrical resistance of the gas sensor member. be. When the gas sensor has the above-mentioned means for deforming the gas sensor member, the gas sensor member can be deformed and the detection sensitivity can be adjusted according to the type and concentration of the gas to be detected.
　本開示の一側面は、単層カーボンナノチューブの表面の少なくとも一部に導電性高分子を含む有機層を形成する第一工程と、有機層が設けられた上記単層カーボンナノチューブを含有する分散液を調製し、上記分散液を基材に接触させることによって、上記基材上に単層カーボンナノチューブを含むガス吸着層を設ける第二工程と、を有し、上記ガス吸着層における複数の単層カーボンナノチューブは互いに電気的に接続されている、ガスセンサ部材の製造方法を提供する。 One aspect of the present disclosure is a first step of forming an organic layer containing a conductive polymer on at least a part of the surface of the single-walled carbon nanotube, and a dispersion liquid containing the single-walled carbon nanotube provided with the organic layer. A second step of providing a gas adsorption layer containing single-walled carbon nanotubes on the substrate by contacting the dispersion liquid with the substrate, and having a plurality of single layers in the gas adsorption layer. Carbon nanotubes provide a method for manufacturing gas sensor members that are electrically connected to each other.
　上記ガスセンサ部材の製造方法は、単層カーボンナノチューブの表面の少なくとも一部に、導電性高分子を含む有機層を形成することを含むことによって、上述のようなガスセンサ部材を製造することができる。 The method for manufacturing the gas sensor member can manufacture the gas sensor member as described above by including forming an organic layer containing a conductive polymer on at least a part of the surface of the single-walled carbon nanotube.
　上記第一工程が、単層カーボンナノチューブと、アニリンと、酸化剤と、を含有する溶液中で、上記単層カーボンナノチューブの表面上にポリアニリンを重合させることによって、上記有機層を形成する工程であってよい。 The first step is a step of forming the organic layer by polymerizing polyaniline on the surface of the single-walled carbon nanotubes in a solution containing the single-walled carbon nanotubes, aniline, and an oxidizing agent. It may be there.
　上記第一工程が、単層カーボンナノチューブと、ポリアニリンと、を含有する溶液中で、上記単層カーボンナノチューブの表面上にポリアニリンを付着させることによって、上記有機層を形成する工程であってよい。 The first step may be a step of forming the organic layer by adhering polyaniline on the surface of the single-walled carbon nanotubes in a solution containing the single-walled carbon nanotubes and polyaniline.
　本開示の一側面は、ガスセンサ部材に評価対象となる気体を接触させる工程を有し、上記ガスセンサ部材が、上述のガスセンサ部材である、ガス検知方法を提供する。 One aspect of the present disclosure includes a step of bringing a gas to be evaluated into contact with a gas sensor member, and provides a gas detection method in which the gas sensor member is the gas sensor member described above.
　上記ガス検知方法は、上述のガスセンサ部材を用いることから、感度に優れ、ノイズが低減されたガス検知を行うことができる。 Since the gas detection method uses the gas sensor member described above, gas detection with excellent sensitivity and reduced noise can be performed.
　上記ガス検知方法は、二酸化炭素、一酸化窒素、二硫化硫黄、及び三酸化硫黄からなる群より選択される少なくとも一種のガスを検知するため方法であってよい。 The gas detection method may be a method for detecting at least one gas selected from the group consisting of carbon dioxide, nitric oxide, sulfur disulfide, and sulfur trioxide.
　本開示の一側面は、ガスセンサ部材を変形させる工程と、上記ガスセンサ部材に評価対象となる気体を接触させる工程と、を有し、上記ガスセンサ部材が、上述のガスセンサ部材である、微量ガス検知方法を提供する。 One aspect of the present disclosure includes a step of deforming a gas sensor member and a step of bringing a gas to be evaluated into contact with the gas sensor member, wherein the gas sensor member is the above-mentioned gas sensor member, a trace gas detection method. I will provide a.
　上記ガス検知方法は、上述のガスセンサ部材を用いることから、感度に優れ、ノイズが低減されたガス検知を行うことができる。 Since the gas detection method uses the gas sensor member described above, gas detection with excellent sensitivity and reduced noise can be performed.
　上記微量ガス検知方法は、二酸化炭素、一酸化窒素、二硫化硫黄、及び三酸化硫黄からなる群より選択される少なくとも一種のガスを検知するため方法であってよい。 The trace gas detection method may be a method for detecting at least one gas selected from the group consisting of carbon dioxide, nitric oxide, sulfur disulfide, and sulfur trioxide.
　本開示によれば、感度に優れ、測定の際のノイズの低減が可能なガスセンサ部材、及びその製造方法を提供できる。本開示によればまた、感度に優れ、測定の際のノイズの低減が可能なガスセンサを提供できる。本開示によればまた、感度に優れ、ノイズが低減されたガス検知方法、及び微量ガス検知方法を提供できる。 According to the present disclosure, it is possible to provide a gas sensor member having excellent sensitivity and capable of reducing noise during measurement, and a method for manufacturing the gas sensor member. According to the present disclosure, it is also possible to provide a gas sensor having excellent sensitivity and capable of reducing noise during measurement. According to the present disclosure, it is also possible to provide a gas detection method having excellent sensitivity and reduced noise, and a trace gas detection method.
図１は、ガスセンサ部材の一部断面を示す模式図である。FIG. 1 is a schematic view showing a partial cross section of a gas sensor member. 図２は、ガスセンサ部材の一部端面を示す模式図である。FIG. 2 is a schematic view showing a partial end face of the gas sensor member. 図３は、ガスセンサの一例を示す模式図である。FIG. 3 is a schematic diagram showing an example of a gas sensor. 図４は、ガスセンサの一例を示す模式図である。FIG. 4 is a schematic diagram showing an example of a gas sensor. 図５は、ポリアニリンの単分子層が外側表面に形成された単層カーボンナノチューブのラマンスペクトルである。FIG. 5 is a Raman spectrum of a single-walled carbon nanotube in which a monomolecular layer of polyaniline is formed on the outer surface. 図６は、ポリアニリンの単分子層が外側表面に形成された単層カーボンナノチューブの外観の一部を示す電子顕微鏡写真である。FIG. 6 is an electron micrograph showing a part of the appearance of a single-walled carbon nanotube in which a monomolecular layer of polyaniline is formed on the outer surface. 図７は、ガスセンサ部材のラマンスペクトルである。FIG. 7 is a Raman spectrum of the gas sensor member. 図８は、ガスセンサ部材の外観の一部を示す電子顕微鏡写真である。FIG. 8 is an electron micrograph showing a part of the appearance of the gas sensor member. 図９は、ガスセンサ部材の評価装置を示す模式図である。FIG. 9 is a schematic view showing an evaluation device for a gas sensor member. 図１０は、ガスセンサ部材のサイクル特性の評価結果を示すグラフである。FIG. 10 is a graph showing the evaluation results of the cycle characteristics of the gas sensor member. 図１１は、ガスセンサ部材のセンサ特性と、検知対象ガスの濃度との関係を示すグラフである。FIG. 11 is a graph showing the relationship between the sensor characteristics of the gas sensor member and the concentration of the gas to be detected. 図１２は、ガスセンサ部材の変形量と、ガスセンサ特性との関係を示すグラフである。FIG. 12 is a graph showing the relationship between the amount of deformation of the gas sensor member and the characteristics of the gas sensor. 図１３は、ガスセンサ部材のセンサ特性と、検知対象ガスの濃度との関係を示すグラフである。FIG. 13 is a graph showing the relationship between the sensor characteristics of the gas sensor member and the concentration of the gas to be detected. 図１４は、ガスセンサ部材のセンサ特性と、検知対象ガスの濃度との関係を示すグラフである。FIG. 14 is a graph showing the relationship between the sensor characteristics of the gas sensor member and the concentration of the gas to be detected. 図１５は、ガスセンサ部材のセンサ特性と、検知対象ガスの種類との関係を示すグラフである。FIG. 15 is a graph showing the relationship between the sensor characteristics of the gas sensor member and the type of gas to be detected.
　以下、場合によって図面を参照しながら、本開示の実施形態について説明する。ただし、以下の実施形態は、本開示を説明するための例示であり、本開示を以下の内容に限定する趣旨ではない。上下左右等の位置関係は、特に断らない限り、図面に示す位置関係に基づくものとする。各要素の寸法比率は図面に図示された比率に限られるものではない。 Hereinafter, embodiments of the present disclosure will be described with reference to the drawings as the case may be. However, the following embodiments are examples for explaining the present disclosure, and are not intended to limit the present disclosure to the following contents. Unless otherwise specified, the positional relationship such as up, down, left, and right shall be based on the positional relationship shown in the drawings. The dimensional ratio of each element is not limited to the ratio shown in the drawings.
　本明細書において例示する材料は特に断らない限り、１種を単独で又は２種以上を組み合わせて用いることができる。組成物中の各成分の含有量は、組成物中の各成分に該当する物質が複数存在する場合には、特に断らない限り、組成物中に存在する当該複数の物質の合計量を意味する。 Unless otherwise specified, the materials exemplified in this specification may be used alone or in combination of two or more. The content of each component in the composition means, when a plurality of substances corresponding to each component in the composition are present, the total amount of the plurality of substances present in the composition unless otherwise specified. ..
＜ガスセンサ部材＞
　ガスセンサ部材の一実施形態は、基材と、上記基材の表面上に設けられたガス吸着層と、を有する。上記ガス吸着層は、互いに電気的に接続された複数の単層カーボンナノチューブを含む。上記単層カーボンナノチューブは表面の少なくとも一部に有機層を有しており、当該有機層は導電性高分子を含む。なお、上記ガス吸着層は有機層を有しない単層カーボンナノチューブを含んでいてもよい。 <Gas sensor member>
One embodiment of the gas sensor member has a base material and a gas adsorption layer provided on the surface of the base material. The gas adsorption layer contains a plurality of single-walled carbon nanotubes electrically connected to each other. The single-walled carbon nanotube has an organic layer on at least a part of the surface, and the organic layer contains a conductive polymer. The gas adsorption layer may contain single-walled carbon nanotubes having no organic layer.
　図１は、ガスセンサ部材の一部断面を示す模式図である。ガスセンサ部材１００は、基材２と、基材２の表面上に設けられたガス吸着層４とを有する。ガス吸着層４は複数の単層カーボンナノチューブ６を含み、単層カーボンナノチューブ６は、互いに電気的に接続されている。単層カーボンナノチューブ６は表面の少なくとも一部に有機層を有している（不図示）。 FIG. 1 is a schematic view showing a partial cross section of the gas sensor member. The gas sensor member 100 has a base material 2 and a gas adsorption layer 4 provided on the surface of the base material 2. The gas adsorption layer 4 contains a plurality of single-walled carbon nanotubes 6, and the single-walled carbon nanotubes 6 are electrically connected to each other. The single-walled carbon nanotube 6 has an organic layer on at least a part of the surface (not shown).
　基材２の形状は特に制限されるものではなく、例えば、板状、ブロック状等であってよい。基材２の形状が板状である場合、その厚みによって、シート及びフィルムであってよい。基材２は、例えば、孔を有しない一様な材料であってよく、多孔質体等であってもよい。基材２が多孔質体である（つまり、多孔質基材である）と、ガスセンサ部材１００におけるガス吸着層４の表面積をより拡張可能であることから好ましい。図２は基材２が多孔質体の場合のガスセンサ部材の一部端面を示す模式図である。図２に示されるようなガスセンサ部材１０２は、多孔質基材に由来する細孔８を有することから、当該ガスセンサ部材１０２であれば、ガスセンサ部材１０２自体をガスが透過できることから、ガスセンサ部材を検知ガスの流路中に設置する等が可能であり、ガスセンサの設計の幅を広げることができる。図２に示されるガスセンサ部材１０２は、例えば、ガスセンサの小型化等にも有用である。 The shape of the base material 2 is not particularly limited, and may be, for example, a plate shape, a block shape, or the like. When the base material 2 has a plate shape, it may be a sheet or a film depending on its thickness. The base material 2 may be, for example, a uniform material having no pores, or may be a porous body or the like. It is preferable that the base material 2 is a porous body (that is, a porous base material) because the surface area of the gas adsorption layer 4 in the gas sensor member 100 can be further expanded. FIG. 2 is a schematic view showing a partial end face of the gas sensor member when the base material 2 is a porous body. Since the gas sensor member 102 as shown in FIG. 2 has pores 8 derived from the porous substrate, the gas sensor member 102 can detect the gas sensor member because gas can permeate through the gas sensor member 102 itself. It can be installed in the gas flow path, etc., and the range of gas sensor design can be expanded. The gas sensor member 102 shown in FIG. 2 is also useful for, for example, miniaturization of the gas sensor.
　基材２は、例えば、伸縮性を有する基材であってよい。伸縮性を有するとは、外力が加わらない状態の基材のサイズを基準として、外力を加えることで伸張させることが可能であり、且つ外力を除いた際に基準のサイズ又はそれに近いサイズに収縮することができることをいう。伸縮性を有する基材は、例えば、外力を加えて１００％伸張した後、誤差１％程度で初期の形状に収縮できるものであることが好ましい。 The base material 2 may be, for example, a base material having elasticity. Having elasticity means that it can be stretched by applying an external force based on the size of the base material in a state where no external force is applied, and shrinks to the standard size or a size close to the standard size when the external force is removed. It means that you can do it. It is preferable that the stretchable base material can be, for example, stretched 100% by applying an external force and then contracted to the initial shape with an error of about 1%.
　基材２を構成する材料は、例えば、ポリジメチルシロキサン、ポリウレタン、スチレン・ブタジエンゴム、ブタジエンゴム、クロロプレンゴム、アクリロニトリル・ブタジエンゴム、イソプレンゴム、ブチルゴム、エチレン・プロピレンゴム、アクリルゴム、ヒドリンゴム、及びクロロスルホン化ポリエチレン等であってよい。基材２として伸縮性を有する多孔質基材を使用する場合には、基材２を構成する材料は、例えば、ポリジメチルシロキサンを含んでよく、ポリジメチルシロキサンからなってもよい。 The materials constituting the base material 2 are, for example, polydimethylsiloxane, polyurethane, styrene-butadiene rubber, butadiene rubber, chloroprene rubber, acrylonitrile-butadiene rubber, isoprene rubber, butyl rubber, ethylene / propylene rubber, acrylic rubber, hydrin rubber, and chloro. It may be sulfonated polyethylene or the like. When a porous base material having elasticity is used as the base material 2, the material constituting the base material 2 may contain, for example, polydimethylsiloxane, or may be made of polydimethylsiloxane.
　ガス吸着層４は単層カーボンナノチューブ６を含むが、例えば、単層カーボンナノチューブ６からなってもよい。ガス吸着層４は互いに電気的に接続された単層カーボンナノチューブ６によって、面内方向に通電可能な層となっている。ガス吸着層４は、例えば、単層カーボンナノチューブ６で構成されるメッシュ形状を有していてもよい。上記メッシュ形状は、例えば、複数の単層カーボンナノチューブ６によって構成される電気的なネットワーク構造ということもできる。 The gas adsorption layer 4 contains the single-walled carbon nanotubes 6, but may be made of, for example, the single-walled carbon nanotubes 6. The gas adsorption layer 4 is a layer that can be energized in the in-plane direction by the single-walled carbon nanotubes 6 electrically connected to each other. The gas adsorption layer 4 may have, for example, a mesh shape composed of single-walled carbon nanotubes 6. The mesh shape can be said to be, for example, an electrical network structure composed of a plurality of single-walled carbon nanotubes 6.
　単層カーボンナノチューブは表面の少なくとも一部又は全部に有機層を有する。有機層が設けられている単層カーボンナノチューブの表面とは、少なくとも、単層カーボンナノチューブの外側表面を含む表面を意味し、好ましくは、単層カーボンナノチューブの外側表面のみを意味する。上記有機層は、上記単層カーボンナノチューブの外側表面に設けられていてもよく、上記単層カーボンナノチューブの外側表面のみに設けられていてもよい。 Single-walled carbon nanotubes have an organic layer on at least part or all of the surface. The surface of the single-walled carbon nanotube provided with the organic layer means at least the surface including the outer surface of the single-walled carbon nanotube, and preferably only the outer surface of the single-walled carbon nanotube. The organic layer may be provided on the outer surface of the single-walled carbon nanotubes, or may be provided only on the outer surface of the single-walled carbon nanotubes.
　上記有機層は、例えば、導電性高分子を含む複数の層で構成されてもよく、単分子層であってもよい。当該単分子層は導電性高分子のみで構成される層であってよい。 The organic layer may be composed of a plurality of layers including a conductive polymer, or may be a monomolecular layer. The monomolecular layer may be a layer composed of only a conductive polymer.
　上記有機層に含まれる導電性高分子は、測定対象となる気体分子を吸着可能であり、単層カーボンナノチューブとの間で電子の授受が可能である導電性高分子であってよい。導電性高分子は、例えば、正孔輸送能を有する導電性高分子等であってよい。導電性高分子は、例えば、芳香族系の導電性高分子であってよい。導電性高分子は、測定対象となるガスの種類等に応じて、適宜選択することができる。導電性高分子は、例えば、ポリアニリン、ポリリオフェン、ポリピロール、ポリパラフェニレン、ポリフェニレンビニレン、及びポリフェニレンスルファド等を含み、好ましくはポリアニリンを含み、より好ましくはポリアニリンである。 The conductive polymer contained in the organic layer may be a conductive polymer capable of adsorbing gas molecules to be measured and transferring electrons to and from single-walled carbon nanotubes. The conductive polymer may be, for example, a conductive polymer having a hole transporting ability. The conductive polymer may be, for example, an aromatic conductive polymer. The conductive polymer can be appropriately selected depending on the type of gas to be measured and the like. The conductive polymer contains, for example, polyaniline, polyriophene, polypyrrole, polyparaphenylene, polyphenylene vinylene, polyphenylene sulfide and the like, preferably containing polyaniline, and more preferably polyaniline.
　単層カーボンナノチューブは、例えば、表面に極性官能基を有してよく、外側表面に極性官能基を有していてよい。単層カーボンナノチューブが表面に極性官能基を有することで、有機層との密着性を向上させることができる。有機層と単層カーボンナノチューブの表面との密着性が向上することで、ガスの吸着による有機層の化学環境の変化をより一層確実にカーボンナノチューブへ伝達することが可能であり、感度低下をより抑制することができる。極性官能基としては、例えば、水酸基、カルボニル基、及びカルボキシ基等が挙げられる。 The single-walled carbon nanotube may have, for example, a polar functional group on the surface and a polar functional group on the outer surface. Since the single-walled carbon nanotubes have a polar functional group on the surface, the adhesion to the organic layer can be improved. By improving the adhesion between the organic layer and the surface of the single-walled carbon nanotubes, it is possible to more reliably transmit changes in the chemical environment of the organic layer due to gas adsorption to the carbon nanotubes, further reducing sensitivity. It can be suppressed. Examples of the polar functional group include a hydroxyl group, a carbonyl group, a carboxy group and the like.
　単層カーボンナノチューブは欠陥等が少ないものが望ましく、開口を有しなくてよい。 It is desirable that the single-walled carbon nanotubes have few defects and do not have to have openings.
　上記導電性高分子の含有量の下限値は、上記単層カーボンナノチューブの全質量を基準として、例えば、５質量％以上、１０質量％以上、又は３０質量％以上であってよい。導電性高分子の含有量が単層カーボンナノチューブに対して所定量以上であることによって、感度をより向上させることができる。上記導電性高分子の含有量の上限値は、上記単層カーボンナノチューブの全質量を基準として、例えば、６０質量％以下、５０質量％以下、又は４０質量％以下であってよい。導電性高分子の含有量が単層カーボンナノチューブに対して上記範囲内であることによって、感度をより向上させることができる。上記導電性高分子の含有量は上述の範囲内で調整してよく、上記単層カーボンナノチューブの全質量を基準として、例えば、５～６０質量％、１０～５０質量％、又は３０～４０質量％であってよい。 The lower limit of the content of the conductive polymer may be, for example, 5% by mass or more, 10% by mass or more, or 30% by mass or more, based on the total mass of the single-walled carbon nanotubes. When the content of the conductive polymer is a predetermined amount or more with respect to the single-walled carbon nanotubes, the sensitivity can be further improved. The upper limit of the content of the conductive polymer may be, for example, 60% by mass or less, 50% by mass or less, or 40% by mass or less based on the total mass of the single-walled carbon nanotubes. When the content of the conductive polymer is within the above range with respect to the single-walled carbon nanotubes, the sensitivity can be further improved. The content of the conductive polymer may be adjusted within the above range, and based on the total mass of the single-walled carbon nanotubes, for example, 5 to 60% by mass, 10 to 50% by mass, or 30 to 40% by mass. May be%.
＜ガスセンサ部材の製造方法＞
　上述のようなガスセンサ部材は、例えば、以下のような方法によって製造することができる。ガスセンサ部材の製造方法の一実施形態は、単層カーボンナノチューブの表面の少なくとも一部に導電性高分子を含む有機層を形成する第一工程（以下、有機層形成工程ともいう）と、有機層が設けられた上記単層カーボンナノチューブを含有する分散液を調製し、上記分散液を基材に接触させることによって、上記基材上に単層カーボンナノチューブを含むガス吸着層を設ける第二工程（以下、ガス吸着層形成工程ともいう）と、を有する。 <Manufacturing method of gas sensor member>
The gas sensor member as described above can be manufactured by, for example, the following method. One embodiment of the method for manufacturing a gas sensor member includes a first step of forming an organic layer containing a conductive polymer on at least a part of the surface of a single-walled carbon nanotube (hereinafter, also referred to as an organic layer forming step) and an organic layer. A second step (a second step) in which a dispersion liquid containing the single-walled carbon nanotubes provided with the above-mentioned material is prepared, and the dispersion liquid is brought into contact with the base material to provide a gas adsorption layer containing the single-walled carbon nanotubes on the base material. Hereinafter, it is also referred to as a gas adsorption layer forming step).
　単層カーボンナノチューブは、市販のものを用いてもよく、別途調製したものを用いてもよい。単層カーボンナノチューブを調製する場合は、例えば、アーク放電法、レーザー蒸着法、及び化学的気相成長法等を用いることができる。 As the single-walled carbon nanotube, a commercially available one may be used, or a separately prepared one may be used. When preparing single-walled carbon nanotubes, for example, an arc discharge method, a laser vapor deposition method, a chemical vapor deposition method, or the like can be used.
　ガス吸着層は単層カーボンナノチューブを複数含むことから、個々の単層カーボンナノチューブの性能は多少ばらつきのあるものであっても使用することができる。単層カーボンナノチューブは、ジグザグ型（ｚｉｇｚａｇ型）単層カーボンナノチューブ、カイラル型（ｃｈｉｒａｌ型）単層カーボンナノチューブ、及びアームチェア型（ａｒｍ－ｃｈａｉｒ型）単層カーボンナノチューブのいずれも用いることができるが、好ましくはジグザグ型（ｚｉｇｚａｇ型）単層カーボンナノチューブ、及びカイラル型（ｃｈｉｒａｌ型）単層カーボンナノチューブである。単層カーボンナノチューブとして、カイラル型（ｃｈｉｒａｌ型）単層カーボンナノチューブを用いる場合のカイラル角は特に制限されるものではなく、求める電気的特性に応じて適宜調整してよい。 Since the gas adsorption layer contains a plurality of single-walled carbon nanotubes, even if the performance of each single-walled carbon nanotube varies slightly, it can be used. As the single-walled carbon nanotubes, any of zigzag-type single-walled carbon nanotubes, chiral-type single-walled carbon nanotubes, and armchair-type single-walled carbon nanotubes can be used. , Preferably zigzag type single-walled carbon nanotubes and chiral type single-walled carbon nanotubes. When a chiral type single-walled carbon nanotube is used as the single-walled carbon nanotube, the chiral angle is not particularly limited and may be appropriately adjusted according to the desired electrical characteristics.
　単層カーボンナノチューブの直径は、例えば、０．５～５．０ｎｍ、０．５～４．０ｎｍ、又は０．４～１．０ｎｍであってよい。単層カーボンナノチューブの長さは、例えば、１０～５００００００ｎｍ、２０～２００００００ｎｍ、又は１００～１００００００ｎｍであってよい。 The diameter of the single-walled carbon nanotubes may be, for example, 0.5 to 5.0 nm, 0.5 to 4.0 nm, or 0.4 to 1.0 nm. The length of the single-walled carbon nanotubes may be, for example, 10 to 5000000 nm, 20 to 2000000 nm, or 100 to 1000000 nm.
　単層カーボンナノチューブは表面に極性官能基を有するものであってよい。単層カーボンナノチューブの表面が極性官能基を有することで、有機層との密着性を向上させることができ、ガスセンサ部材の耐久性を向上できる。単層カーボンナノチューブに対して酸化処理等によって表面に極性官能基を導入して用いてもよい。極性官能基としては、例えば、水酸基、カルボニル基、及びカルボキシ基等が挙げられる。表面に極性官能基を有する多層カーボンナノチューブを用いる場合、例えば、ガスセンサ部材の製造方法は、第一工程の前に、単層カーボンナノチューブを酸化処理する工程を更に有してもよい。 The single-walled carbon nanotube may have a polar functional group on the surface. Since the surface of the single-walled carbon nanotube has a polar functional group, the adhesion to the organic layer can be improved, and the durability of the gas sensor member can be improved. A polar functional group may be introduced into the surface of the single-walled carbon nanotube by an oxidation treatment or the like. Examples of the polar functional group include a hydroxyl group, a carbonyl group, a carboxy group and the like. When multi-walled carbon nanotubes having a polar functional group on the surface are used, for example, the method for manufacturing a gas sensor member may further include a step of oxidizing the single-walled carbon nanotubes before the first step.
　酸化処理工程は、単層カーボンナノチューブの燃焼を抑制し、単層カーボンナノチューブの表面に開口が設けられることを抑制する観点から、酸化処理の条件を選択することができる。酸化処理工程は、酸素を含む雰囲気下で行うことができ、好ましくは空気中で行う。 In the oxidation treatment step, the conditions of the oxidation treatment can be selected from the viewpoint of suppressing the combustion of the single-walled carbon nanotubes and suppressing the formation of openings on the surface of the single-walled carbon nanotubes. The oxidation treatment step can be performed in an atmosphere containing oxygen, preferably in air.
　酸化処理工程における熱処理の温度の上限値は、例えば、３５０℃以下、３００℃以下、又は２００℃以下であってよい。酸化処理工程における熱処理温度の上限値を上記範囲内とすることによって、単層カーボンナノチューブに開口が設けられることを抑制し、仮に開口が設けられた場合であってもその開口径が広がることを十分に抑制することができる。酸化処理工程における熱処理温度の下限値は、例えば、１５０℃以上、１７０℃以上、又は１８０℃以上であってよい。酸化処理工程における熱処理温度の下限値を上記範囲内とすることで、単層カーボンナノチューブの表面に効率的に極性官能基を導入することができる。酸化処理工程における熱処理の温度は上述の範囲内で調整してよく、例えば、１５０～３５０℃、１７０～３００℃、又は１８０～２００℃であってよい。 The upper limit of the heat treatment temperature in the oxidation treatment step may be, for example, 350 ° C. or lower, 300 ° C. or lower, or 200 ° C. or lower. By setting the upper limit of the heat treatment temperature in the oxidation treatment step within the above range, it is possible to suppress the formation of openings in the single-walled carbon nanotubes and to widen the opening diameter even if the openings are provided. It can be sufficiently suppressed. The lower limit of the heat treatment temperature in the oxidation treatment step may be, for example, 150 ° C. or higher, 170 ° C. or higher, or 180 ° C. or higher. By setting the lower limit of the heat treatment temperature in the oxidation treatment step within the above range, the polar functional group can be efficiently introduced into the surface of the single-walled carbon nanotube. The temperature of the heat treatment in the oxidation treatment step may be adjusted within the above range, and may be, for example, 150 to 350 ° C., 170 to 300 ° C., or 180 to 200 ° C.
　酸化処理工程における熱処理の時間は、例えば、０．１～１５時間、０．１～５時間、０．５～５時間、１～５時間、又は１～３時間であってよい。酸化処理工程における熱処理の時間を上記範囲内とすることで、単層カーボンナノチューブに開口が設けられることをより一層確実に抑制することができる。 The heat treatment time in the oxidation treatment step may be, for example, 0.1 to 15 hours, 0.1 to 5 hours, 0.5 to 5 hours, 1 to 5 hours, or 1 to 3 hours. By setting the heat treatment time in the oxidation treatment step within the above range, it is possible to more reliably suppress the provision of openings in the single-walled carbon nanotubes.
　有機層形成工程では、単層カーボンナノチューブの表面の少なくとも一部に、導電性高分子を含む有機層を形成する。有機層を形成する方法としては、例えば、単層カーボンナノチューブの表面上で導電性高分子を与えるモノマーを重合させることによって有機層を形成する方法、及び、予め合成された導電性高分子を単層カーボンナノチューブの表面上に付着させることによって有機層を形成する方法等であってよい。有機層形成工程は、有機層形成の制御がより容易であることから、好ましくは単層カーボンナノチューブの表面上で導電性高分子を与えるモノマーを重合させることによって有機層を形成する方法である。また導電性高分子の分子量等によっては溶解性が低く、溶液及び分散液の調製が困難な場合があり、このような場合には、モノマーを重合させることを含む手段を用いることができる。 In the organic layer forming step, an organic layer containing a conductive polymer is formed on at least a part of the surface of the single-walled carbon nanotube. Examples of the method for forming the organic layer include a method of forming an organic layer by polymerizing a monomer that gives a conductive polymer on the surface of a single-walled carbon nanotube, and a method of forming a conductive polymer that has been synthesized in advance. It may be a method of forming an organic layer by adhering it on the surface of the layered carbon nanotube. Since the organic layer formation is easier to control, the organic layer forming step is preferably a method of forming an organic layer by polymerizing a monomer that gives a conductive polymer on the surface of the single-walled carbon nanotube. Further, depending on the molecular weight of the conductive polymer and the like, the solubility may be low and it may be difficult to prepare a solution and a dispersion. In such a case, a means including polymerizing a monomer can be used.
　有機層に含まれる導電性高分子がポリアニリンを含有する場合、有機層形成工程は、例えば、単層カーボンナノチューブと、アニリンと、酸化剤と、を含有する溶液中で、上記単層カーボンナノチューブの表面上にポリアニリンを重合させることによって、上記有機層を形成する工程であってよく、単層カーボンナノチューブと、ポリアニリンと、を含有する溶液中で、上記単層カーボンナノチューブの表面上にポリアニリンを付着させることによって、上記有機層を形成する工程であってよい。 When the conductive polymer contained in the organic layer contains polyaniline, the organic layer forming step is carried out in a solution containing, for example, a single-walled carbon nanotube, aniline, and an oxidizing agent, in the above-mentioned single-walled carbon nanotube. It may be a step of forming the organic layer by polymerizing polyaniline on the surface, and the polyaniline is adhered on the surface of the single-walled carbon nanotube in a solution containing the single-walled carbon nanotube and the polyaniline. This may be a step of forming the organic layer.
　単層カーボンナノチューブと、アニリンと、酸化剤と、を含有する溶液、及び、単層カーボンナノチューブと、ポリアニリンと、を含有する溶液は、例えば、分散液であってよい。分散媒としては、例えば、水、並びに、水及び有機溶媒の混合媒等が挙げられる。 The solution containing the single-walled carbon nanotubes, aniline, and an oxidizing agent, and the solution containing the single-walled carbon nanotubes and polyaniline may be, for example, a dispersion. Examples of the dispersion medium include water and a mixed medium of water and an organic solvent.
　ポリアニリンを重合するために用いる酸化剤は、例えば、過硫酸アンモニウム、過硫酸ナトリウム、及び過硫酸カリウム等が挙げられる。 Examples of the oxidizing agent used for polymerizing polyaniline include ammonium persulfate, sodium persulfate, and potassium persulfate.
　ガス吸着層形成工程は、有機層が設けられた上記単層カーボンナノチューブを含有する分散液を調製し、上記分散液を基材に接触させることによって、上記基材上に単層カーボンナノチューブを含むガス吸着層を設ける。分散液を接触させる基材は、上述のガスセンサ部材を構成する基材として例示したものを用いることができる。 In the gas adsorption layer forming step, a dispersion liquid containing the single-walled carbon nanotubes provided with an organic layer is prepared, and the dispersion liquid is brought into contact with the base material to contain the single-walled carbon nanotubes on the base material. A gas adsorption layer is provided. As the base material to which the dispersion liquid is brought into contact, those exemplified as the base material constituting the above-mentioned gas sensor member can be used.
　有機層が設けられた上記単層カーボンナノチューブを含有する分散液を調製する際の分散媒は、水、並びに、水及び有機溶媒の混合媒等が挙げられる。水としては、例えば、イオン交換水等を使用できる。 Examples of the dispersion medium for preparing the dispersion liquid containing the single-walled carbon nanotubes provided with the organic layer include water and a mixed medium of water and an organic solvent. As the water, for example, ion-exchanged water or the like can be used.
　上記分散液を調製する際には、単層カーボンナノチューブを分散させるために、分散剤を使用してもよい。分散剤としては、例えば、Ｚｎ－Ａｌ分散剤、及びラウリル硫酸ナトリウム等が挙げられる。Ｚｎ－Ａｌ分散剤は、亜鉛（Ｚｎ）とアルミニウム（Ａｌ）とを基にした錯体である。Ｚｎ－Ａｌ分散剤は、例えば、亜鉛アセテートとアルミナイトレートとをそれぞれ１ｇずつ、純水２０ｇに溶解させて調製した溶液を、３７３Ｋの温度で、２時間還流させるゾルーゲル合成によって調製することができる。Ｚｎ－Ａｌ錯体は、単層カーボンナノチューブの表面に付着しないため、単層カーボンナノチューブが良好に分散することを促進しながら、上記有機層の表面に被覆層を形成することが無く、好適に使用できる。分散液の調製は、例えば、単層カーボンナノチューブ、分散剤及び分散媒の混合物を超音波処理することで行ってもよい。超音波処理の時間は、例えば、３０分間以上、又は６０分間以上であってよい。 When preparing the above dispersion, a dispersant may be used to disperse the single-walled carbon nanotubes. Examples of the dispersant include Zn-Al dispersants and sodium lauryl sulfate. The Zn-Al dispersant is a complex based on zinc (Zn) and aluminum (Al). The Zn-Al dispersant can be prepared, for example, by sol-gel synthesis in which a solution prepared by dissolving 1 g each of zinc acetate and aluminum nitrate in 20 g of pure water is refluxed at a temperature of 373 K for 2 hours. .. Since the Zn-Al complex does not adhere to the surface of the single-walled carbon nanotubes, it is suitably used because it does not form a coating layer on the surface of the organic layer while promoting good dispersion of the single-walled carbon nanotubes. can. The dispersion may be prepared, for example, by sonicating a mixture of single-walled carbon nanotubes, a dispersant and a dispersion medium. The sonication time may be, for example, 30 minutes or longer, or 60 minutes or longer.
　上記分散液と基材とを接触させる方法は、例えば、基材を分散液に浸漬させる方法、又は基材に分散液を滴下若しくは噴霧する方法であってよい。 The method of bringing the dispersion liquid into contact with the base material may be, for example, a method of immersing the base material in the dispersion liquid, or a method of dropping or spraying the dispersion liquid on the base material.
　分散液と基材とを接触させ、基材上に分散液の液膜が形成されたのち、必要に応じて、加熱処理等を行ってもよい。加熱処理によって、液膜中の分散媒濃度を低減してもよい。加熱処理の温度は、例えば、８０～１２０℃、又は９０～１００℃であってよい。分散媒の低減を容易にする観点から、上記加熱処理は、減圧環境下で行うこともできる。 After the dispersion liquid and the base material are brought into contact with each other to form a liquid film of the dispersion liquid on the base material, heat treatment or the like may be performed as necessary. The concentration of the dispersion medium in the liquid film may be reduced by heat treatment. The temperature of the heat treatment may be, for example, 80 to 120 ° C. or 90 to 100 ° C. From the viewpoint of facilitating the reduction of the dispersion medium, the above heat treatment can also be performed in a reduced pressure environment.
　基材上にガス吸着層を形成することで得られたガスセンサ部材には、分散剤が残存し得る。当該分散剤の残存量を低減する観点から、例えば、酸による洗浄を行ってもよい。酸としては、例えば、希硝酸等を用いることができる。 The dispersant may remain in the gas sensor member obtained by forming the gas adsorption layer on the base material. From the viewpoint of reducing the residual amount of the dispersant, for example, cleaning with an acid may be performed. As the acid, for example, dilute nitric acid or the like can be used.
＜ガスセンサ＞
　上述のガスセンサ部材は、ガスセンサの構成部材として使用できる。ガスセンサの一実施形態は、ガスセンサ部材と、上記ガスセンサ部材と電気的に接続されたセンサ電極と、を備える。 <Gas sensor>
The above-mentioned gas sensor member can be used as a constituent member of the gas sensor. One embodiment of the gas sensor includes a gas sensor member and a sensor electrode electrically connected to the gas sensor member.
　図３はガスセンサの一例を示す模式図である。ガスセンサ２００は、支持体４０、支持体４０上に設けられたガスセンサ部材１００、及び、ガスセンサ部材１００と電気的に接続されたセンサ電極５０を備える。ガスセンサ２００は、ガスセンサ部材１００における電気抵抗の変化を、センサ電極５０を介して検出することによって、ガスセンサ部材１００が晒されている環境におけるガスを検知することができる。 FIG. 3 is a schematic diagram showing an example of a gas sensor. The gas sensor 200 includes a support 40, a gas sensor member 100 provided on the support 40, and a sensor electrode 50 electrically connected to the gas sensor member 100. The gas sensor 200 can detect the gas in the environment to which the gas sensor member 100 is exposed by detecting the change in the electric resistance in the gas sensor member 100 via the sensor electrode 50.
　支持体４０は特に制限されるものではなく、例えば、ガラス基材、セラミック基材、及び樹脂基材等であってよい。支持体４０として、伸縮性を有する基材を用いてもよい。ガスセンサ部材１００としてガスセンサ部材を構成する基材が伸縮性を有する基材を用いる場合、支持体４０として伸縮性基材を用いることが好ましい。センサ電極５０は、例えば、金、白金、銀、銅、アルミニウム、ニッケル、及びクロム等の金属からなる電極であってよく、好ましくは、金、白金、及び銅からなる電極である。 The support 40 is not particularly limited, and may be, for example, a glass base material, a ceramic base material, a resin base material, or the like. As the support 40, a stretchable base material may be used. When the base material constituting the gas sensor member uses a stretchable base material as the gas sensor member 100, it is preferable to use the stretchable base material as the support 40. The sensor electrode 50 may be, for example, an electrode made of a metal such as gold, platinum, silver, copper, aluminum, nickel, and chromium, and is preferably an electrode made of gold, platinum, and copper.
　ガスセンサは、ガスセンサ部材を固定する固定具を更に備え、上記固定具が上記ガスセンサ部材を変形させる手段を有していてもよい。上記固定具は、例えば、ガスセンサ部材の端部を固定する支持部材と、ガスセンサ部材に張力を作用させることによってガスセンサ部材を変形可能な押圧部材とを有してよい。上記支持部材及び押圧部材の形状は特に限定されるものではない。 The gas sensor may further include a fixture for fixing the gas sensor member, and the fixture may have a means for deforming the gas sensor member. The fixture may have, for example, a support member for fixing an end portion of the gas sensor member and a pressing member capable of deforming the gas sensor member by applying tension to the gas sensor member. The shapes of the support member and the pressing member are not particularly limited.
　図４はガスセンサの一例を示す模式図であり、上述のような固定具の一例を有する例を示した。ガスセンサ２０２は、シート状のガスセンサ部材１０２、ガスセンサ部材１０２と電気的に接続されたセンサ電極５０、及びガスセンサ部材１０２を変形させることが可能な固定具８０を備える。固定具８０は、測定対象となるガスを通すための貫通孔７０Ａを有する支持部材６０と、上記支持部材６０を収容可能な貫通孔６０Ａを有する押圧部材７０とで構成される。 FIG. 4 is a schematic diagram showing an example of a gas sensor, and shows an example having an example of a fixture as described above. The gas sensor 202 includes a sheet-shaped gas sensor member 102, a sensor electrode 50 electrically connected to the gas sensor member 102, and a fixture 80 capable of deforming the gas sensor member 102. The fixture 80 includes a support member 60 having a through hole 70A for passing a gas to be measured, and a pressing member 70 having a through hole 60A capable of accommodating the support member 60.
　支持部材６０は筒状の本体部６２とフランジ部６４とを有する。押圧部材７０は筒状の本体部７２とフランジ部７４とを有する。支持部材６０の筒状の本体部６２の内径は、押圧部材７０の筒状の本体部７２の外形よりも大きく、押圧部材７０の筒状の本体部７２は支持部材６０の本体部６２に収容することができる。図４の（ｂ）に示すように、押圧部材７０の本体部７２が、支持部材６０の本体部６２に収容されるように、シート状のガスセンサ部材１０２を押圧することによって、ガスセンサ部材１０２に張力を作用させ、所望の倍率で伸張させることができる。支持部材６０におけるフランジ部６４のガスセンサ部材１０２側の表面は、ガスセンサ部材１０２の滑りを抑制するような加工が施されていてよい。 The support member 60 has a cylindrical main body portion 62 and a flange portion 64. The pressing member 70 has a cylindrical main body portion 72 and a flange portion 74. The inner diameter of the cylindrical main body 62 of the support member 60 is larger than the outer diameter of the tubular main body 72 of the pressing member 70, and the tubular main body 72 of the pressing member 70 is housed in the main body 62 of the support member 60. can do. As shown in FIG. 4B, the sheet-shaped gas sensor member 102 is pressed against the gas sensor member 102 so that the main body 72 of the pressing member 70 is accommodated in the main body 62 of the support member 60. Tension can be applied to stretch at the desired magnification. The surface of the flange portion 64 on the gas sensor member 102 side of the support member 60 may be processed so as to prevent the gas sensor member 102 from slipping.
　図４では、支持部材６０及び押圧部材７０はともにフランジ部を有する例で示したが、フランジ部を有しないでもよい。支持部材６０及び押圧部材７０がフランジ部を有する場合には、シート状のガスセンサ部材１０２を押圧し変形させる際の調整がより容易なものとなる。 FIG. 4 shows an example in which both the support member 60 and the pressing member 70 have a flange portion, but the support member 60 and the pressing member 70 may not have a flange portion. When the support member 60 and the pressing member 70 have a flange portion, adjustment when pressing and deforming the sheet-shaped gas sensor member 102 becomes easier.
＜ガス検知方法及び微量ガス検知方法＞
　上述のガスセンサ部材は、感度に優れ、測定におけるノイズも低減可能であることから、ガス検知に有用である。ガス検知方法の一実施形態は、ガスセンサ部材に評価対象となる気体を接触させる工程を有する。評価対象となるガスとしては、例えば、二酸化炭素、一酸化窒素、二硫化硫黄、及び三酸化硫黄からなる群より選択される少なくとも一種のガスであってよい。すなわち、ガス検知方法は、二酸化炭素、一酸化窒素、二硫化硫黄、及び三酸化硫黄からなる群より選択される少なくとも一種のガスを検知するため方法であってよい。 <Gas detection method and trace gas detection method>
The above-mentioned gas sensor member is useful for gas detection because it has excellent sensitivity and can reduce noise in measurement. One embodiment of the gas detection method includes a step of bringing a gas to be evaluated into contact with a gas sensor member. The gas to be evaluated may be, for example, at least one gas selected from the group consisting of carbon dioxide, nitric oxide, sulfur disulfide, and sulfur trioxide. That is, the gas detection method may be a method for detecting at least one gas selected from the group consisting of carbon dioxide, nitric oxide, sulfur disulfide, and sulfur trioxide.
　上述のガスセンサ部材は、変形させることによって、単層カーボンナノチューブ同士の電気的な接点を減じ、ガスセンサ部材の電気抵抗を上昇させるなどの調整が可能であり、これによってより微量のガスの検知にも使用することができる。微量ガスの検知方法の一実施形態は、ガスセンサ部材を変形させる工程と、上記ガスセンサ部材に評価対象となる気体を接触させる工程と、を有する。微量ガスの検知方法においては、検知対象となるガスの濃度等に応じて、ガスセンサ部材を変形させてよい。例えば、測定対象となるガスの濃度が一定以上になると検出できるようにガスセンサ部材を変形させ、抵抗値を調整しておくことによって、対象ガスの漏れを検知するために用いることができる。 By deforming the gas sensor member described above, it is possible to make adjustments such as reducing the electrical contacts between single-walled carbon nanotubes and increasing the electrical resistance of the gas sensor member, thereby detecting even a smaller amount of gas. Can be used. One embodiment of the method for detecting a trace gas includes a step of deforming a gas sensor member and a step of bringing the gas sensor member into contact with a gas to be evaluated. In the method of detecting a trace gas, the gas sensor member may be deformed according to the concentration of the gas to be detected and the like. For example, by deforming the gas sensor member so that it can be detected when the concentration of the gas to be measured exceeds a certain level and adjusting the resistance value, it can be used to detect the leakage of the target gas.
　上述のガス検知方法及び微量ガス検知方法における検出感度は、測定対象の気体分子の濃度が、測定対象となる気体分子を含む混合ガス（例えば、大気）の標準状態における体積を基準として、例えば、１０ｐｐｍ以下であっても検出が可能な感度である。上述のガス検知方法及び微量ガス検知方法における検知感度は、上述のガスセンサ部材を変形することによって調整することができ、測定対象の気体分子の濃度が、測定対象となる気体分子を含む混合ガス（例えば、大気）の標準状態における体積を基準として、例えば、０．１ｐｐｍ以下、１ｐｐｍ以下、２ｐｐｍ以下、又は５ｐｐｍ以下とすることもできる。 The detection sensitivity in the above-mentioned gas detection method and trace gas detection method is, for example, based on the volume of the gas molecule to be measured in the standard state of the mixed gas (for example, the atmosphere) containing the gas molecule to be measured. It is a sensitivity that can be detected even if it is 10 ppm or less. The detection sensitivity in the above-mentioned gas detection method and trace gas detection method can be adjusted by deforming the above-mentioned gas sensor member, and the concentration of the gas molecule to be measured is a mixed gas containing the gas molecule to be measured ( For example, it may be 0.1 ppm or less, 1 ppm or less, 2 ppm or less, or 5 ppm or less based on the volume in the standard state of (atmosphere).
　以上、幾つかの実施形態について説明したが、本開示は上記実施形態に何ら限定されるものではない。また、上述した実施形態についての説明内容は、互いに適用することができる。 Although some embodiments have been described above, the present disclosure is not limited to the above embodiments. Further, the contents of the description of the above-described embodiments can be applied to each other.
　以下、実施例及び比較例を参照して本開示の内容をより詳細に説明する。ただし、本開示は、下記の実施例に限定されるものではない。 Hereinafter, the contents of the present disclosure will be described in more detail with reference to Examples and Comparative Examples. However, the present disclosure is not limited to the following examples.
（実施例１）
［有機層形成工程］
　単層カーボンナノチューブ（株式会社名城カーボン製、商品名：ＥＣ１．０）を大気中、２５０℃の条件下で１０分間の酸化処理を行うことで、極性官能基を導入した。上記酸化処理された単層カーボンナノチューブ４５ｍｇと、アニリン１０ｍＬ（１０．２ｍｇ）と、塩酸（濃度：０．１ｍｏｌ／Ｌ）５０ｍＬとを容器に測り取り、超音波処理を３０分間施すことによって分散液を調製した。上記分散液を撹拌しながら、０～５℃の温度に冷却し、当該温度の分散液に、あらかじめ過硫酸アンモニウム２３０ｍｇを５０ｍＬの純水に溶解させて調製した、２０ｍｍｏｌ／Ｌの過硫酸アンモニウム水溶液の全量を徐々に滴下して加えた。過硫酸アンモニウムの全量を滴下後、０～５℃の温度で４時間分散液を撹拌しながら、アニリンの重合を行った。 (Example 1)
[Organic layer forming process]
A polar functional group was introduced by subjecting a single-walled carbon nanotube (manufactured by Meijo Carbon Co., Ltd., trade name: EC1.0) to an oxidation treatment in the air at 250 ° C. for 10 minutes. 45 mg of the oxidized single-walled carbon nanotubes, 10 mL (10.2 mg) of aniline, and 50 mL of hydrochloric acid (concentration: 0.1 mol / L) are measured in a container and subjected to ultrasonic treatment for 30 minutes to disperse the dispersion. Was prepared. While stirring the above dispersion, cool it to a temperature of 0 to 5 ° C., and dissolve 230 mg of ammonium persulfate in 50 mL of pure water in advance in the dispersion at that temperature to prepare a total amount of 20 mmol / L ammonium persulfate aqueous solution. Was gradually added dropwise. After dropping the entire amount of ammonium persulfate, aniline was polymerized while stirring the dispersion at a temperature of 0 to 5 ° C. for 4 hours.
　重合後、分散液中の固形物をろ過によって回収し、イオン交換水を用いて洗浄した。イオン交換水の洗浄後、エタノールによって固形物をさらに洗浄した後、真空乾燥させることで、ポリアニリンの単分子層を外側表面に有する単層カーボンナノチューブを調製した。得られた単層カーボンナノチューブについて、有機層が外側表面に形成されていることをラマンスペクトル及び電子顕微鏡観察によって、確認した。図５にラマンスペクトルを示し、図６に電子顕微鏡写真を示す。 After the polymerization, the solid matter in the dispersion was recovered by filtration and washed with ion-exchanged water. After washing with ion-exchanged water, the solid matter was further washed with ethanol, and then vacuum dried to prepare single-walled carbon nanotubes having a monomolecular layer of polyaniline on the outer surface. It was confirmed by Raman spectrum and electron microscopic observation that the organic layer was formed on the outer surface of the obtained single-walled carbon nanotubes. FIG. 5 shows a Raman spectrum, and FIG. 6 shows an electron micrograph.
　図５のラマンスペクトルに示されるとおり、酸化処理前の単層カーボンナノチューブのラマンスペクトル（図５中、ＳＷＣＮＴで示すスペクトル）を基準として、酸化処理された単層カーボンナノチューブのラマンスペクトル（図５中、оｘ－ＳＷＣＮＴで示すスペクトル）は、単層カーボンナノチューブに由来するＲＢＭ（Ｒａｄｉａｌ　Ｂｒｅａｔｈｉｎｇ　Ｍｏｄｅ、１００～３００ｃｍ－１の波数域に観測される単層カーボンナノチューブに特有のピーク）、Ｄバンド（１３５０ｃｍ－１付近の波数域に観測される単層カーボンナノチューブに特有のピーク）及びＧバンド（１５９０ｃｍ－１付近の波数域に観測される単層カーボンナノチューブに特有のピーク）に変化がないことが確認された。さらに、上述の操作によって得られた固形物に対するラマンスペクトル（図５中、оｘ－ＳＷＣＮＴ－ＰＡＮＩ（ｉｎ－ｓｉｔｕ）で示すスペクトル）では、単層カーボンナノチューブ及び酸化処理された単層カーボンナノチューブでは観測されなかったピークが１０００～１５００ｃｍ－１の波数域に観測されており、これはポリアニリン（ＰＡＮＩ）のラマンスペクトルに由来するピークに相当することから、上記操作によって、単層カーボンナノチューブの外側表面に有機層が形成されていることが確認できた。図６の（ａ）及び（ｂ）は単層カーボンナノチューブの外側表面に有機層が形成された状態（оｘ－ＳＷＣＮＴ－ＰＡＮＩ）の外観を示し、図６の（ｃ）及び（ｄ）は、乾燥させたоｘ－ＳＷＣＮＴ－ＰＡＮＩとＺｎ－Ａｌ分散剤とを再びイオン交換水に添加し、分散させて調製した分散液におけるоｘ－ＳＷＣＮＴ－ＰＡＮＩの外観を示す。図６の（ｃ）及び（ｄ）は分散液を対象とした観察ではあるものの、電子顕微鏡観察のためイオン交換水は除去された状態にある。 As shown in the Raman spectrum of FIG. 5, the Raman spectrum of the single-walled carbon nanotubes subjected to the oxidation treatment (in FIG. 5) with reference to the Raman spectrum of the single-walled carbon nanotubes before the oxidation treatment (spectrum indicated by SWCNT in FIG. 5). , spectrum) shown in оx-SWCNT, peaks unique to the single-walled carbon nanotubes observed in a wave number region of RBM derived from the single-walled carbon nanotubes (Radial Breathing Mode, 100 ~ 300cm -1), D -band (1350 cm - it is confirmed no change in specific peak) in single-walled carbon nanotubes observed in a wave number region in the vicinity of -1 characteristic peak) and G band (1590 cm in single-walled carbon nanotubes observed in a wave number range near 1 rice field. Furthermore, in the Raman spectrum for the solid matter obtained by the above operation (spectrum shown by оx-SWCNT-PANI (in-situ) in FIG. 5), it was observed in the single-walled carbon nanotubes and the oxidized single-walled carbon nanotubes. Unexisted peaks have been observed in the wavenumber range of 1000-1500 cm- 1 , which corresponds to peaks derived from the Raman spectrum of polyaniline (PANI). It was confirmed that the organic layer was formed. 6 (a) and 6 (b) show the appearance of an organic layer formed on the outer surface of the single-walled carbon nanotube (оx-SWCNT-PANI), and FIGS. 6 (c) and 6 (d) show the appearance. The appearance of оx-SWCNT-PANI in the dispersion prepared by adding the dried оx-SWCNT-PANI and the Zn-Al dispersant to the ion-exchanged water again and dispersing them is shown. Although the observations of FIGS. 6 (c) and 6 (d) are for the dispersion liquid, the ion-exchanged water has been removed for the electron microscope observation.
［基材の調製工程］
　ポリジメチルシロキサンからなる多孔質基材を、シュガーテンプレート（ｓｕｇａｒ　ｔｅｍｐｌａｔｅｓ）法に基づいて調製した。まず、砂糖の粉末を押し固めてブロック状に成形し、鋳型を調製した。この鋳型に、シリコーンエラストマー（デュポン・東レ・スペシャルティ・マテリアル株式会社製、商品名：ｓｉｌｐｏｔ１８４）と、硬化剤としてシリコーン樹脂用触媒（デュポン・東レ・スペシャルティ・マテリアル株式会社製、商品名：ｓｉｌｐｏｔ１８４ｃａｔ）とが、質量比で１０対１となるように混合した溶液を含浸させた。上記溶液が含浸した状態で、４５℃に加熱し、当該温度で５時間処理することによってシリコーンエラストマーを固化させた。その後、砂糖で構成される鋳型ごとイオン交換水の中にいれ、６０℃に加熱しながら超音波処理をかける、砂糖を溶解し除去することによって、ポリジメチルシロキサンからなる多孔質基材を調製した。 [Base material preparation process]
A porous substrate made of polydimethylsiloxane was prepared based on the sugar templates method. First, sugar powder was compacted and molded into a block to prepare a mold. In this mold, a silicone elastomer (manufactured by DuPont Toray Specialty Material Co., Ltd., trade name: silpot184) and a catalyst for silicone resin as a curing agent (manufactured by DuPont Toray Specialty Material Co., Ltd., trade name: silpot184cat) are used. However, the mixed solution was impregnated so as to have a mass ratio of 10: 1. In the state of being impregnated with the above solution, the silicone elastomer was solidified by heating to 45 ° C. and treating at the temperature for 5 hours. Then, the whole mold composed of sugar was placed in ion-exchanged water and subjected to ultrasonic treatment while heating at 60 ° C. to dissolve and remove the sugar to prepare a porous substrate made of polydimethylsiloxane. ..
［ガス吸着層形成工程］
　上述のようにして調製したポリアニリンの単分子層を外側表面に有する単層カーボンナノチューブ５０ｍｇと、Ｚｎ－Ａｌ分散剤２００ｍｇと、イオン交換水２０ｍＬとを容器に測り取り、超音波処理を６０分間施すことで、分散液を調製した。当該分散液に、上記多孔質基材を浸漬し、分散液を十分に含浸させた。その後、多孔質基材を分散液から取出し、９０℃の温度で３０分間加熱処理することによって、多孔質基材の表面にガス吸着層を形成し、ガスセンサ部材を得た。なお、ガスセンサ部材の形状は多孔質基材の形状に準じ、縦３ｃｍ、横１ｃｍ、厚さ０．２ｃｍであった。多孔質基材の表面に上述の単層カーボンナノチューブを含むガス吸着層が形成されていることをラマンスペクトル及び電子顕微鏡観察によって、確認した。図７にラマンスペクトルを示し、図８に電子顕微鏡写真を示す。 [Gas adsorption layer forming process]
50 mg of single-walled carbon nanotubes having a monomolecular layer of polyaniline prepared as described above on the outer surface, 200 mg of Zn-Al dispersant, and 20 mL of ion-exchanged water are measured in a container and subjected to ultrasonic treatment for 60 minutes. Therefore, a dispersion was prepared. The porous substrate was immersed in the dispersion and sufficiently impregnated with the dispersion. Then, the porous substrate was taken out from the dispersion liquid and heat-treated at a temperature of 90 ° C. for 30 minutes to form a gas adsorption layer on the surface of the porous substrate to obtain a gas sensor member. The shape of the gas sensor member was 3 cm in length, 1 cm in width, and 0.2 cm in thickness according to the shape of the porous base material. It was confirmed by Raman spectrum and electron microscope observation that the gas adsorption layer containing the above-mentioned single-walled carbon nanotubes was formed on the surface of the porous substrate. FIG. 7 shows a Raman spectrum, and FIG. 8 shows an electron micrograph.
　図７のラマンスペクトルに示されるとおり、多孔質基材のラマンスペクトル（図７のＰｏｒｏｕｓ　ＰＤＭＳで示すスペクトル）に対して、上述の操作で得られた部材のラマンスペクトル（図７のоｘ－ＳＷＣＮＴ／Ｐｏｒｏｕｓ　ＰＤＭＳで示すスペクトル）では、単層カーボンナノチューブに由来するＧバンド、及びポリジメチルシロキサンに由来する２８００～３０００ｃｍ－１付近の波数域のピークが観測されており、且つポリアニリンに由来する１０００～１５００ｃｍ－１の波数域のピークが観測されており、所望のガス吸着層が多孔質基材上に形成されてことが確認できた。また、図８に示すとおり、上述の操作で得られた部材の表面（図８の（ｂ）で示す写真）には、多孔質基材の表面（図８の（ａ）で示す写真）には観測されなかった繊維状物を確認することができ、図７の測定結果を裏付けている。 As shown in the Raman spectrum of FIG. 7, the Raman spectrum of the member obtained by the above operation (оx-SWCNT / of FIG. 7) is relative to the Raman spectrum of the porous substrate (spectrum shown by Porous PDMS in FIG. 7). In the spectrum shown by Porous PDMS), a G band derived from single-walled carbon nanotubes and a peak in the wavenumber range around 2800 to 3000 cm -1 derived from polydimethylsiloxane are observed, and 1000 to 1500 cm derived from polyaniline. A peak in the wavenumber region of -1 was observed, and it was confirmed that the desired gas adsorption layer was formed on the porous substrate. Further, as shown in FIG. 8, the surface of the member obtained by the above operation (photograph shown in FIG. 8B) is the surface of the porous substrate (photograph shown in FIG. 8A). Can confirm the fibrous material that was not observed, which supports the measurement result of FIG. 7.
＜ガスセンサ部材の評価：サイクル特性＞
　上述のようにして得られたガスセンサ部材の性能を評価した。具体的には、図９に示すようなガスセンサ部材の評価装置（ガスセンサ）を構成し、炭酸ガス（二酸化炭素）に対する応答を評価した。図９に示すガスセンサ３００は、中央に開口部を有する支持部材６６及び７６によって、ガスセンサ部材１０４を挟み込み固定した状態で、供給ラインＬｉ（Ｌｉｎｅ　ｉｎ）からガスセンサ部材１０４にサンプルガスを供給し、排出ラインＬｏ（Ｌｉｎｅ　ｏｕｔ）からガスセンサ部材１０４を通過したサンプルガスを排出する。ここで、ガスセンサ部材１０４と電気的に接続したセンサ電極５０を介して、電流計によって、サンプルガス供給時に生じるガスセンサ部材の電気的な状態の変化（抵抗値の変化）を観測した。供給ラインＬｉから供給されるガスは、空気のボンベ及び炭酸ガスのボンベに接続されており、空気と炭酸ガスとの混合比が調整可能に設定されている。 <Evaluation of gas sensor member: Cycle characteristics>
The performance of the gas sensor member obtained as described above was evaluated. Specifically, an evaluation device (gas sensor) for a gas sensor member as shown in FIG. 9 was configured, and the response to carbon dioxide gas (carbon dioxide) was evaluated. The gas sensor 300 shown in FIG. 9 supplies sample gas from the supply line Li (Line in) to the gas sensor member 104 in a state where the gas sensor member 104 is sandwiched and fixed by the support members 66 and 76 having an opening in the center, and is discharged. The sample gas that has passed through the gas sensor member 104 is discharged from the line Lo (Line out). Here, a change in the electrical state (change in resistance value) of the gas sensor member that occurs when the sample gas is supplied was observed by an ammeter via the sensor electrode 50 electrically connected to the gas sensor member 104. The gas supplied from the supply line Li is connected to an air cylinder and a carbon dioxide gas cylinder, and the mixing ratio of air and carbon dioxide gas is set to be adjustable.
　混合ガスの標準状態における体積を基準として、炭酸ガスの濃度が５ｐｐｍとなるように調整した混合ガスをガスセンサ部材に供給することで、性能評価を行った。測定は２５℃の環境下で行い、抵抗値の測定は、電圧を１Ｖに設定して行った。比較のために、ポリアニリンの単分子層を形成せずに、極性官能基を導入した単層カーボンナノチューブを含むガス吸着層を多孔質基材上に形成した部材を調製し、実施例１と同様の評価を行った。結果を図１０に示す。 Performance was evaluated by supplying the gas sensor member with the mixed gas adjusted so that the concentration of carbon dioxide gas was 5 ppm based on the volume of the mixed gas in the standard state. The measurement was performed in an environment of 25 ° C., and the resistance value was measured by setting the voltage to 1 V. For comparison, a member in which a gas adsorption layer containing a single-walled carbon nanotube into which a polar functional group was introduced was formed on a porous substrate without forming a monomolecular layer of polyaniline was prepared, and the same as in Example 1. Was evaluated. The results are shown in FIG.
　図１０中、「Ｇａｓ　ｉｎ」は空気の供給から混合ガスの供給に変更したことを意味し、「Ｇａｓ　ｏｕｔ」は混合ガスの供給を遮断し空気の供給に変更したことを意味する（図１１～図１３、及び図１５においても同様の表記を用いる）。図１０に示すグラフの縦軸のＲｅｓｐｏｎｓｅは、検知対象となるガス（例えば、炭酸ガス）を所定濃度で含む混合ガス雰囲気下におけるガスセンサ部材の抵抗値をＲｇａｓとし、空気雰囲気下におけるガスセンサ部材の抵抗値をＲａｉｒとした場合の、［（Ｒａｉｒ－Ｒｇａｓ）／Ｒａｉｒ］×１００で与えられる値であり、この値が大きいことは検知対象となるガスに対する感度が高いことを意味する。 In FIG. 10, "Gas in" means that the supply of air has been changed to the supply of mixed gas, and "Gas out" means that the supply of mixed gas has been cut off and changed to the supply of air (FIG. 11). -The same notation is used in FIGS. 13 and 15). In the response on the vertical axis of the graph shown in FIG. 10, the resistance value of the gas sensor member in a mixed gas atmosphere containing a gas to be detected (for example, carbon dioxide) at a predetermined concentration is R gas, and the resistance value of the gas sensor member in an air atmosphere is set. When the resistance value is R air , it is a value given by [(R air- R gas ) / R air ] × 100, and a large value means that the sensitivity to the gas to be detected is high. ..
　図１０のグラフに示されるとおり、ポリアニリンの単分子層が形成された単層カーボンナノチューブを用いて製造したガスセンサ部材は、ポリアニリンの単分子層を有しない単層カーボンナノチューブを用いて製造したガスセンサ部材と同様に、混合ガスの供給開始によく追従して、縦軸のＲｅｓｐｏｎｓｅの値が上昇している。さらにポリアニリンの単分子層が形成された単層カーボンナノチューブを用いて製造したガスセンサ部材の測定結果において縦軸のＲｅｓｐｏｎｓｅの最大値が、ポリアニリンの単分子層を有しない単層カーボンナノチューブを用いて製造したガスセンサ部材の測定結果における縦軸のＲｅｓｐｏｎｓｅの最大値よりも大きく、およそ２倍の感度を有していることが確認された。また、グラフの形状から、ノイズが抑制されていることも確認できる。 As shown in the graph of FIG. 10, the gas sensor member manufactured by using the single-walled carbon nanotube on which the polyaniline single-walled layer is formed is the gas sensor member manufactured by using the single-walled carbon nanotube without the polyaniline single-walled layer. Similarly, the value of Response on the vertical axis rises well following the start of supply of the mixed gas. Furthermore, in the measurement results of the gas sensor member manufactured using the single-walled carbon nanotubes on which the polyaniline single-walled layer was formed, the maximum value of Response on the vertical axis was manufactured using the single-walled carbon nanotubes without the polyaniline single-walled layer. It was confirmed that the sensitivity was larger than the maximum value of Response on the vertical axis in the measurement result of the gas sensor member and had about twice the sensitivity. It can also be confirmed from the shape of the graph that noise is suppressed.
　図１０に示されるとおり、実施例１で調製したガスセンサ部材は、複数回の混合ガスの供給を行っても、１回目の供給と同等に炭酸ガスを検知しており、また、混合ガスの供給を遮断した後に初期化されている。したがって、実施例１のガスセンサ部材は複数回のセンシングにも用いることができる。 As shown in FIG. 10, the gas sensor member prepared in Example 1 detects carbon dioxide gas in the same manner as the first supply even if the mixed gas is supplied a plurality of times, and the mixed gas is supplied. It is initialized after shutting off. Therefore, the gas sensor member of the first embodiment can also be used for a plurality of times of sensing.
＜ガスセンサ部材の評価：検知対象ガスの濃度依存性＞
　検知対象となる炭酸ガスの濃度を変更したこと以外は、上述のサイクル特性評価と同様にしてガスセンサ部材の評価を行った。炭酸ガスの濃度を、１ｐｐｍ、３ｐｐｍ、５ｐｐｍ、２５ｐｐｍ及び５０ｐｐｍに調整して、混合ガスを供給した際の抵抗値の変動を測定した。結果を図１１に示す。 <Evaluation of gas sensor member: Concentration dependence of detection target gas>
The gas sensor member was evaluated in the same manner as the cycle characteristic evaluation described above, except that the concentration of carbon dioxide gas to be detected was changed. The concentration of carbon dioxide was adjusted to 1 ppm, 3 ppm, 5 ppm, 25 ppm and 50 ppm, and the fluctuation of the resistance value when the mixed gas was supplied was measured. The results are shown in FIG.
　図１１に示されるとおり、炭酸ガスの濃度が１ｐｐｍであっても、炭酸ガスの吸着によって抵抗値の低下を確認できており、検知対象ガスの濃度が比較的低濃度の場合であっても十分検知できることが確認された。 As shown in FIG. 11, even if the concentration of carbon dioxide gas is 1 ppm, the decrease in resistance value can be confirmed by the adsorption of carbon dioxide gas, and it is sufficient even when the concentration of the gas to be detected is relatively low. It was confirmed that it could be detected.
＜ガスセンサ部材の評価：ガスセンサ部材の変形による影響＞
　ガスセンサ部材を伸張させることによるガスセンサ特性への影響を評価した。ガスセンサ部材を変形させて用いること以外は、上述のサイクル特性評価と同様にしてガスセンサ部材の評価を行った。ガスセンサ部材の変形は、ガスセンサ部材における歪みが、０面積％、３０面積％、及び６０面積％となるように調整することで行った。上記歪みとは、ガスセンサ部材の上面視した際の面積をＡ１とし、面内方向にガスセンサ部材を伸張した後の上面視した際の面積をＡ２とした場合に、（Ａ２／Ａ１）×１００で与えられる値である。結果を図１２に示す。 <Evaluation of gas sensor member: Effect of deformation of gas sensor member>
The effect of stretching the gas sensor member on the gas sensor characteristics was evaluated. The gas sensor member was evaluated in the same manner as the above-mentioned cycle characteristic evaluation except that the gas sensor member was deformed and used. The deformation of the gas sensor member was performed by adjusting the distortion in the gas sensor member to be 0 area%, 30 area%, and 60 area%. The above-mentioned distortion is defined as (A 2 / A 1 ) when the area of the gas sensor member when viewed from above is A 1 and the area when the gas sensor member is stretched in the in-plane direction and then viewed from above is A 2. ) It is a value given by × 100. The results are shown in FIG.
　図１２に示すとおり、ガスセンサ部材の変形量が大きくなることによって、Ｒｅｓｐｏｎｓｅが向上していることが確認された。すなわち、ガスセンサ部材を変形させることによって、更に感度を上昇させることができ、例えば、検知対象ガスの濃度が小さい場合などにガスセンサ部材を変形させることで検知可能となり得ることが確認された。 As shown in FIG. 12, it was confirmed that the response was improved by increasing the amount of deformation of the gas sensor member. That is, it was confirmed that the sensitivity can be further increased by deforming the gas sensor member, and detection can be performed by deforming the gas sensor member, for example, when the concentration of the detection target gas is small.
＜ガスセンサ部材の評価：検知対象ガスの濃度依存性その２＞
　ガスセンサ部材の伸張に加えて、検知対象ガスの濃度を変更した際のガスセンサ特性を評価した。ガスセンサ部材における歪みが、０面積％、３０面積％、及び６０面積％である各種ガスセンサ部材を対象として、炭酸ガスの濃度を、１ｐｐｍ、３ｐｐｍ、５ｐｐｍ、２５ｐｐｍ及び５０ｐｐｍに調整して、混合ガスを供給した際の抵抗値の変動を測定した。結果を図１３及び図１４に示す。 <Evaluation of gas sensor member: Concentration dependence of detection target gas Part 2>
In addition to the extension of the gas sensor member, the gas sensor characteristics when the concentration of the gas to be detected was changed were evaluated. For various gas sensor members whose strain in the gas sensor member is 0 area%, 30 area%, and 60 area%, the concentration of carbon dioxide gas is adjusted to 1 ppm, 3 ppm, 5 ppm, 25 ppm, and 50 ppm to prepare a mixed gas. The fluctuation of the resistance value when supplied was measured. The results are shown in FIGS. 13 and 14.
　図１３に示されるとおり、ガスセンサ部材における歪みが増えるにつれて、感度の上昇幅が大きくなっていることが確認できる。また、図１３及び図１４に示されるとおり、その影響は検知対象ガスの濃度が大きいほど、大きくなっている。 As shown in FIG. 13, it can be confirmed that the increase in sensitivity increases as the distortion in the gas sensor member increases. Further, as shown in FIGS. 13 and 14, the influence increases as the concentration of the detection target gas increases.
＜ガスセンサ部材の評価：検知対象ガスの違いによる影響＞
　検知対象ガスを炭酸ガスに代えて酸素を用いたこと以外は、上述のサイクル特性評価と同様にしてガスセンサ部材の評価を行った。結果を図１５に示す。実施例１で調製したガスセンサ部材を用いた場合には、検知対象ガスを酸素にした場合でも抵抗値の変化は観測されたものの、その変化量は炭酸ガスの場合に比べて小さいことが確認された。導電性高分子の種類、ガスセンサ部材の伸張等の調整によって、検出が対象ガスに応じた使用が望ましいことが確認された。 <Evaluation of gas sensor member: Effect of difference in detection target gas>
The gas sensor member was evaluated in the same manner as the above-mentioned cycle characteristic evaluation except that oxygen was used instead of carbon dioxide as the detection target gas. The results are shown in FIG. When the gas sensor member prepared in Example 1 was used, a change in the resistance value was observed even when the gas to be detected was oxygen, but it was confirmed that the amount of change was smaller than that in the case of carbon dioxide gas. rice field. It was confirmed that it is desirable to use the detection according to the target gas by adjusting the type of conductive polymer and the elongation of the gas sensor member.
　本開示によれば、感度に優れ、測定の際のノイズの低減が可能なガスセンサ部材、及びその製造方法を提供できる。本開示によればまた、感度に優れ、測定の際のノイズの低減が可能なガスセンサを提供できる。本開示によればまた、感度に優れ、ノイズが低減されたガス検知方法、及び微量ガス検知方法を提供できる。 According to the present disclosure, it is possible to provide a gas sensor member having excellent sensitivity and capable of reducing noise during measurement, and a method for manufacturing the gas sensor member. According to the present disclosure, it is also possible to provide a gas sensor having excellent sensitivity and capable of reducing noise during measurement. According to the present disclosure, it is also possible to provide a gas detection method having excellent sensitivity and reduced noise, and a trace gas detection method.
　２…基材、４…ガス吸着層、６…単層カーボンナノチューブ、８…細孔、４０…支持体、５０…センサ電極、６０，６６…支持部材、６２，７２…本体部、６４，７４…フランジ部、７０…押圧部材、８０…固定具、１００，１０２，１０４…ガスセンサ部材、２００，２０２，３００…ガスセンサ。 2 ... Substrate, 4 ... Gas adsorption layer, 6 ... Single-walled carbon nanotube, 8 ... Pore, 40 ... Support, 50 ... Sensor electrode, 60, 66 ... Support member, 62, 72 ... Main body, 64, 74 ... Flange portion, 70 ... Pressing member, 80 ... Fixture, 100, 102, 104 ... Gas sensor member, 200, 202, 300 ... Gas sensor.

Claims (19)

  1. 　基材と、
    　前記基材の表面上に設けられたガス吸着層と、を有し、
    　前記ガス吸着層は、互いに電気的に接続された複数の単層カーボンナノチューブを含み、
    　前記単層カーボンナノチューブは表面の少なくとも一部に、導電性高分子を含む有機層を有する、ガスセンサ部材。     With the base material
    It has a gas adsorption layer provided on the surface of the base material, and has.
    The gas adsorption layer contains a plurality of single-walled carbon nanotubes electrically connected to each other.
    The single-walled carbon nanotube is a gas sensor member having an organic layer containing a conductive polymer on at least a part of the surface thereof.
  2. 　前記有機層が前記単層カーボンナノチューブの外側表面に設けられている、請求項１に記載のガスセンサ部材。 The gas sensor member according to claim 1, wherein the organic layer is provided on the outer surface of the single-walled carbon nanotube.
  3. 　前記基材は伸縮性を有する、請求項１又は２に記載のガスセンサ部材。 The gas sensor member according to claim 1 or 2, wherein the base material has elasticity.
  4. 　前記基材は多孔質基材である、請求項１～３のいずれか一項に記載のガスセンサ部材。 The gas sensor member according to any one of claims 1 to 3, wherein the base material is a porous base material.
  5. 　前記基材の形状は板状である、請求項１～４のいずれか一項に記載のガスセンサ部材。 The gas sensor member according to any one of claims 1 to 4, wherein the base material has a plate shape.
  6. 　前記有機層は単分子層である、請求項１～５のいずれか一項に記載のガスセンサ部材。 The gas sensor member according to any one of claims 1 to 5, wherein the organic layer is a monomolecular layer.
  7. 　前記導電性高分子はポリアニリンを含有する、請求項１～６のいずれか一項に記載のガスセンサ部材。 The gas sensor member according to any one of claims 1 to 6, wherein the conductive polymer contains polyaniline.
  8. 　前記単層カーボンナノチューブは表面に極性官能基を有する、請求項１～７のいずれか一項に記載のガスセンサ部材。 The gas sensor member according to any one of claims 1 to 7, wherein the single-walled carbon nanotube has a polar functional group on its surface.
  9. 　前記単層カーボンナノチューブは開口を有しない、請求項１～８のいずれか一項に記載のガスセンサ部材。 The gas sensor member according to any one of claims 1 to 8, wherein the single-walled carbon nanotube does not have an opening.
  10. 　前記導電性高分子の含有量が、前記単層カーボンナノチューブの全質量を基準として、５質量％以上である、請求項１～９のいずれか一項に記載のガスセンサ部材。 The gas sensor member according to any one of claims 1 to 9, wherein the content of the conductive polymer is 5% by mass or more based on the total mass of the single-walled carbon nanotubes.
  11. 　ガスセンサ部材と、前記ガスセンサ部材と電気的に接続されたセンサ電極と、を備え、
    　前記ガスセンサ部材が請求項１～１０のいずれか一項に記載のガスセンサ部材である、ガスセンサ。     A gas sensor member and a sensor electrode electrically connected to the gas sensor member are provided.
    The gas sensor, wherein the gas sensor member is the gas sensor member according to any one of claims 1 to 10.
  12. 　前記ガスセンサ部材を固定する固定具を更に備え、
    　前記固定具が前記ガスセンサ部材を変形させる手段を有する、請求項１１に記載のガスセンサ。     Further provided with a fixture for fixing the gas sensor member,
    The gas sensor according to claim 11, wherein the fixture has means for deforming the gas sensor member.
  13. 　単層カーボンナノチューブの表面の少なくとも一部に、導電性高分子を含む有機層を形成する第一工程と、
    　有機層が設けられた前記単層カーボンナノチューブを含有する分散液を調製し、前記分散液を基材に接触させることによって、前記基材の表面上に単層カーボンナノチューブを含むガス吸着層を設ける第二工程と、を有し、
    　前記ガス吸着層における複数の単層カーボンナノチューブは互いに電気的に接続されている、ガスセンサ部材の製造方法。     The first step of forming an organic layer containing a conductive polymer on at least a part of the surface of the single-walled carbon nanotubes,
    A dispersion liquid containing the single-walled carbon nanotubes provided with an organic layer is prepared, and the dispersion liquid is brought into contact with a base material to provide a gas adsorption layer containing the single-walled carbon nanotubes on the surface of the base material. With the second step,
    A method for manufacturing a gas sensor member, wherein a plurality of single-walled carbon nanotubes in the gas adsorption layer are electrically connected to each other.
  14. 　前記第一工程が、単層カーボンナノチューブと、アニリンと、酸化剤と、を含有する溶液中で、前記単層カーボンナノチューブの表面上にポリアニリンを重合させることによって、前記有機層を形成する工程である、請求項１３に記載のガスセンサ部材の製造方法。 The first step is a step of forming the organic layer by polymerizing polyaniline on the surface of the single-walled carbon nanotubes in a solution containing the single-walled carbon nanotubes, aniline, and an oxidizing agent. The method for manufacturing a gas sensor member according to claim 13.
  15. 　前記第一工程が、単層カーボンナノチューブと、ポリアニリンと、を含有する溶液中で、前記単層カーボンナノチューブの表面上にポリアニリンを付着させることによって、前記有機層を形成する工程である、請求項１３に記載のガスセンサ部材の製造方法。 The first step is a step of forming the organic layer by adhering polyaniline on the surface of the single-walled carbon nanotubes in a solution containing the single-walled carbon nanotubes and polyaniline. 13. The method for manufacturing a gas sensor member according to 13.
  16. 　ガスセンサ部材に評価対象となる気体を接触させる工程を有し、
    　前記ガスセンサ部材が、請求項１～１０のいずれか一項に記載のガスセンサ部材である、ガス検知方法。     It has a process of bringing the gas to be evaluated into contact with the gas sensor member.
    The gas detection method, wherein the gas sensor member is the gas sensor member according to any one of claims 1 to 10.
  17. 　二酸化炭素、一酸化窒素、二硫化硫黄、及び三酸化硫黄からなる群より選択される少なくとも一種のガスを検知するため方法である、請求項１６に記載のガス検知方法。 The gas detection method according to claim 16, which is a method for detecting at least one gas selected from the group consisting of carbon dioxide, nitric oxide, sulfur disulfide, and sulfur trioxide.
  18. 　ガスセンサ部材を変形させる工程と、
    　前記ガスセンサ部材に評価対象となる気体を接触させる工程と、を有し、
    　前記ガスセンサ部材が、請求項１～１０のいずれか一項に記載のガスセンサ部材である、微量ガス検知方法。     The process of deforming the gas sensor member and
    It has a step of bringing a gas to be evaluated into contact with the gas sensor member.
    The method for detecting a trace gas, wherein the gas sensor member is the gas sensor member according to any one of claims 1 to 10.
  19. 　二酸化炭素、一酸化窒素、二硫化硫黄、及び三酸化硫黄からなる群より選択される少なくとも一種のガスを検知するため方法である、請求項１８に記載の微量ガス検知方法。 The trace gas detection method according to claim 18, which is a method for detecting at least one gas selected from the group consisting of carbon dioxide, nitric oxide, sulfur disulfide, and sulfur trioxide.
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