WO2024043324A1 - Gas sensor - Google Patents
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- WO2024043324A1 WO2024043324A1 PCT/JP2023/030652 JP2023030652W WO2024043324A1 WO 2024043324 A1 WO2024043324 A1 WO 2024043324A1 JP 2023030652 W JP2023030652 W JP 2023030652W WO 2024043324 A1 WO2024043324 A1 WO 2024043324A1
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Images
Classifications
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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
- the present invention relates to a gas sensor that detects a specific gas.
- This application claims priority based on Japanese Patent Application No. 2022-134176 filed in Japan on August 25, 2022 and Japanese Patent Application No. 2023-132025 filed in Japan on August 14, 2023. Its contents are incorporated here.
- Patent Document 1 proposes a hydrogen gas sensor using a metal oxide.
- Patent Document 2 proposes an oxygen gas sensor and a carbon dioxide gas sensor using an oxygen ion conductor made of a solid electrolyte.
- the hydrogen gas sensor described in Patent Document 1 has a structure in which a hydrogen sensing layer is formed on a substrate, and a pair of electrodes are disposed on this hydrogen sensing layer.
- the hydrogen sensing layer includes a catalyst that dissociates hydrogen gas into protons and electrons, and a metal oxide whose electrical resistance decreases due to the electrons generated by the dissociation of hydrogen gas by the catalyst, and the hydrogen sensing layer contains a catalyst that dissociates hydrogen gas into protons and electrons. It is configured to detect hydrogen gas based on changes in electrical resistance.
- an oxygen ion conductor made of a solid electrolyte is disposed on the surface of an insulating substrate (for example, an alumina substrate), and an oxygen ion conductor made of a solid electrolyte is disposed on the surface of an insulating substrate (for example, an alumina substrate).
- the structure includes an oxygen detection electrode made of a noble metal, a carbon dioxide detection electrode covered with a metal carbonate, and a reference electrode isolated from the sample gas.
- the present invention was made in view of the above-mentioned circumstances, and an object thereof is to provide a gas sensor that has a simple structure, low manufacturing cost, easy handling, and is capable of detecting a specific gas. do.
- a gas sensor includes a conductor-containing porous body in which an electric conductor is contained in an insulating porous body, and an electric conductor-containing porous body with an interval in the extending direction of the conductor-containing porous body.
- a first electrode part and a second electrode part are arranged with a gap between them, and a resistance measuring part measures an electrical resistance value between the first electrode part and the second electrode part.
- the conductor-containing porous body serves as a gas detection section that detects gas.
- the gas sensor has a conductor-containing porous body in which a conductor is contained in an insulating porous body, and the conductor-containing porous body serves as a gas detection portion for detecting gas.
- the conductor-containing porous body serves as a gas detection portion for detecting gas.
- the electrical resistance value changes when it comes into contact with a specific gas. Therefore, when a specific gas is exposed to the conductor-containing porous body, which is the gas detection section, the electrical resistance of the conductor-containing porous body changes. Gas can be detected by measuring the electrical resistance value between the electrode part and the second electrode part.
- a gas sensor according to a second aspect of the present invention is characterized in that in the gas sensor according to the first aspect, the conductor is a thermoelectric material having an absolute value of a Seebeck coefficient of 3 ⁇ V/K or more.
- the conductor contained in the insulating porous body is a thermoelectric material with an absolute value of Seebeck coefficient of 3 ⁇ V/K or more, so the conductor-containing porous body has a specific The electrical resistance value changes greatly when it comes into contact with gas, and the gas can be detected by measuring the electrical resistance value between the first electrode part and the second electrode part using the resistance measuring part. can be performed with high precision.
- a gas sensor according to aspect 3 of the present invention is characterized in that in the gas sensor according to aspect 1 or aspect 2, the conductor is a carbon nanotube.
- the conductor contained in the insulating porous body is carbon nanotube, the conductor-containing porous body has a large electrical resistance value when it comes into contact with a specific gas. By measuring the electrical resistance value between the first electrode section and the second electrode section using the resistance measurement section, gas can be detected with high accuracy.
- a gas sensor according to aspect 4 of the present invention is the gas sensor according to aspect 1 or 2, characterized in that the conductor is an organic thermoelectric material.
- the conductor contained in the insulating porous body is an organic thermoelectric material
- the conductor-containing porous body has an electrical resistance value that decreases when it comes into contact with a specific gas. By measuring the electrical resistance value between the first electrode section and the second electrode section using the resistance measurement section, gas can be detected with high accuracy.
- a gas sensor according to a fifth aspect of the present invention is the gas sensor according to the first or second aspect, wherein the conductor is a nanotube or a nanowire made of a compound semiconductor or a silicon semiconductor.
- the conductor contained in the insulating porous body is a nanotube or nanowire made of a compound semiconductor or a silicon semiconductor, so that the conductor-containing porous body comes into contact with a specific gas.
- the electrical resistance value changes greatly, and by measuring the electrical resistance value between the first electrode part and the second electrode part using the resistance measuring part, gas detection can be performed with high precision. It can be carried out.
- the gas sensor according to aspect 6 of the present invention is the gas sensor according to any one of aspects 1 to 5, characterized in that the insulating porous body is made of any one of paper, thread, nonwoven fabric, cloth, and reed stick. It is said that according to the gas sensor according to aspect 6 of the present invention, the insulating porous body is made of any one of paper, thread, nonwoven fabric, cloth, and reed stick (liquid absorption core).
- a conductor-containing porous body can be easily produced by incorporating a conductor into cloth or a reed stick (liquid-absorbing core).
- the paper in the present invention includes any paper formed by papermaking, and the cloth in the present invention includes any fabric formed by spinning. Furthermore, the conductor-containing porous body can be brought into reliable contact with the gas to be measured, and the gas can be detected with high accuracy. Furthermore, after use, the conductor-containing porous body can be incinerated and disposed of, reducing environmental load.
- a seventh aspect of the present invention is characterized in that, in the gas sensor according to any one of aspects 1 to 6, the gas detected by the gas detection section is hydrogen gas.
- the gas detected by the gas detection section is hydrogen gas
- the resistance measurement section detects an electric current between the first electrode section and the second electrode section. Hydrogen gas can be detected by measuring the resistance value.
- Aspect 8 of the present invention is characterized in that in the gas sensor according to any one of aspects 1 to 6, the gas detected by the gas detection section is oxygen gas.
- the resistance measurement section detects an electric current between the first electrode section and the second electrode section. Oxygen gas can be detected by measuring the resistance value.
- a ninth aspect of the present invention is characterized in that, in the gas sensor according to any one of aspects 1 to 6, the gas detected by the gas detection section is carbon dioxide gas.
- the gas detected by the gas detection section is carbon dioxide gas
- the resistance measurement section detects the difference between the first electrode section and the second electrode section. Carbon dioxide gas can be detected by measuring the electrical resistance value.
- a tenth aspect of the present invention is characterized in that, in the gas sensor according to any one of aspects one to six, the gas detected by the gas detection section is water vapor gas.
- the resistance measurement section detects an electric current between the first electrode section and the second electrode section. Water vapor gas can be detected by measuring the resistance value.
- a gas sensor that has a simple structure, is low in manufacturing cost, is easy to handle, and is capable of detecting a specific gas.
- FIG. 1 is a schematic explanatory diagram of a gas sensor that is an embodiment of the present invention.
- FIG. 1 is a schematic explanatory diagram of a method for manufacturing a conductor-containing porous body used in a gas sensor according to an embodiment of the present invention.
- a gas sensor 10 includes a conductor-containing porous body 20 in which a conductor is contained in an insulating porous body, and an extending direction of the conductor-containing porous body 20.
- a first electrode part 11 and a second electrode part 12 are arranged at intervals, and a resistance measuring part 15 measures the electrical resistance between the first electrode part 11 and the second electrode part 12.
- the first electrode part 11 is disposed at one end of the conductor-containing porous body 20 (the lower end in FIG. 1), and the second electrode part 11 is provided at the other end (the upper end in FIG. 1) of the conductor-containing porous body 20.
- An electrode section 12 is provided.
- the conductor-containing porous body 20 described above is used as a gas detection section that detects a specific gas.
- examples of the specific gas detected by the gas detection unit include hydrogen gas, oxygen gas, carbon dioxide gas, and the like.
- the gas to be detected is hydrogen gas
- the gas sensor 10 is a hydrogen gas sensor that detects hydrogen gas.
- the conductor-containing porous body 20 is an insulating porous body containing a conductor.
- the conductor is preferably a thermoelectric material having an absolute value of the Seebeck coefficient of 3 ⁇ V/K or more. This thermoelectric material has properties as a semiconductor, and has properties as a p-type semiconductor or an n-type semiconductor.
- the conductor-containing porous body 20 may be either a p-type semiconductor or an n-type semiconductor.
- Thermoelectric materials with an absolute value of Seebeck coefficient of 3 ⁇ V/K or more include (a) carbon nanotubes (CNTs), (b) organic thermoelectric materials, (c) nanotubes and nanowires made of compound semiconductors or silicon semiconductors, and (d) noble metal compounds. , (e) carbon material, (f) metal such as Bi, Co, Fe, Ni, etc.
- the thermoelectric material contained in the conductor-containing porous body 20 preferably has an absolute value of Seebeck coefficient of 40 ⁇ V/K or more. Further, the thermoelectric materials (a) to (f) may be combined and used.
- the conductor-containing porous body 20 can be configured by containing carbon nanotubes in the insulating porous body. Note that the Seebeck coefficient of carbon nanotubes is approximately 5 to 170 ⁇ V/K.
- thermoelectric materials examples include PEDOT type (PEDOT:PSS, PEDOT:Tos, etc.), ⁇ -conjugated nickel complex type (poly(nickel-ethylenetetrathiolate)), N-DMBI type (N,N-dimethyl-2-phenyl- 2,3-dihydro-1H-benzoimidazole) and the like.
- PEDOT:PSS PEDOT type
- PEDOT:Tos PEDOT:Tos
- N-DMBI type N,N-dimethyl-2-phenyl- 2,3-dihydro-1H-benzoimidazole
- the Seebeck coefficient of PEDOT:PSS is approximately 10 to 100 ⁇ V/K.
- the Seebeck coefficient of PEDOT:Tos is about 40 to 210 ⁇ V/K.
- the Seebeck coefficient of the ⁇ -conjugated nickel complex system is about -16 to -140 ⁇ V/K.
- the conductor-containing porous body 20 can be configured by containing the organic thermoelectric material in the insulating
- Nanotubes or nanowires made of compound semiconductors or silicon semiconductors include nanotubes or nanowires made of compound semiconductors or silicon semiconductors such as boron nitride nanotubes, Si nanowires, Bi 2 Te 3 Bi 2 Te 3 nanowires, etc. in other porous bodies.
- the conductor-containing porous body 20 can be configured.
- the noble metal compound examples include copper compounds, silver compounds, gold compounds, platinum compounds, and the like. Specifically, a compound of a noble metal element (Cu, Ag, Au, Pt) and S, Se, Te is preferable.
- the conductor-containing porous body 20 can be configured by containing the noble metal compound in the insulating porous body.
- Examples of carbon materials include carbon black and graphite.
- the conductor-containing porous body 20 can be configured by containing the carbon material in the insulating porous body.
- the conductor-containing porous body 20 can be configured by containing metals such as Bi, Co, Fe, and Ni in the insulating porous body. . Note that it is preferable that metals such as Bi, Co, Fe, and Ni be contained in the insulating porous body by a plating method.
- the conductor-containing porous body 20 is an insulating porous body impregnated with carbon nanotubes (CNT), and has semiconductor characteristics, and is a p-type semiconductor or an n-type semiconductor. It has the characteristics of In addition, in this embodiment, the conductor-containing porous body 20 may be either a p-type semiconductor or an n-type semiconductor.
- CNT carbon nanotubes
- the insulating porous material is preferably a fibrous material such as paper, thread, nonwoven fabric, cloth, or reed stick.
- the insulating porous body is paper
- the conductor-containing porous body 20 is CNT-containing paper. That is, paper, which is an insulator, was used as the insulating porous body.
- the fibers may be natural fibers or artificial fibers. Paper, thread, nonwoven fabric, cloth, reed stick, etc. that are a combination of multiple fibers may be used.
- an example of a method for manufacturing the conductor-containing porous body 20 (CNT-containing paper) will be described with reference to FIG. 2.
- pulp fibers are added to pure water and sufficiently stirred to obtain a pulp suspension 51 in which pulp fibers are dispersed.
- a carbon nanotube dispersion liquid 52 is obtained by adding single-walled carbon nanotubes to pure water and stirring thoroughly.
- the proportion of single-walled carbon nanotubes is preferably 0.8% by mass or more and 3.2% by mass or less based on the weight of pulp fibers that are paper raw materials. Also, there is no need to add a dispersant. Further, when obtaining the carbon nanotube dispersion liquid 52, it is preferable to perform ultrasonic treatment for about 30 minutes.
- the above-described pulp suspension 51 and carbon nanotube dispersion 52 are mixed and stirred to obtain a mixed liquid 53. At this time, carbon nanotubes will adhere to the pulp fibers. Then, as shown in FIGS. 2(4) and 2(5), the above-mentioned liquid mixture 53 is made into paper and dried to obtain a conductor-containing porous body 20 (CNT-containing paper).
- the conductor-containing porous body 20 constituting the gas detection section when the conductor-containing porous body 20 constituting the gas detection section is exposed to hydrogen gas, the conductor-containing porous body 20 and the hydrogen gas come into contact with each other, resulting in conductivity.
- the electrical resistance value of the body-containing porous body 20 increases. Therefore, the electrical resistance value between the first electrode part 11 and the second electrode part 12 is measured by the resistance measuring part 15, and when the electrical resistance value increases, it is determined that hydrogen gas is present.
- a conductor-containing porous body 20 in which a conductor is contained in an insulating porous body is used, and this conductor-containing porous body 20 is Since it is a gas detection section that detects gas, when the conductor-containing porous body 20, which is a gas detection section, is exposed to hydrogen gas, the electrical resistance of the conductor-containing porous body 20 changes. become. Therefore, hydrogen gas can be detected by measuring the electrical resistance value between the first electrode section 11 and the second electrode section 12 using the resistance measuring section 15.
- the conductor-containing porous body 20 constituting the gas detection section is an insulating porous body containing a conductor, so carbon nanotubes or the like are arranged.
- the structure is simple and no catalyst or the like is required, manufacturing costs can be significantly reduced.
- the conductor when the conductor is a thermoelectric material with an absolute value of the Seebeck coefficient of 3 ⁇ V/K or more, the conductor-containing porous body 20 is in contact with a specific gas.
- the electrical resistance value will change greatly, so by measuring the electrical resistance value between the first electrode section 11 and the second electrode section 12 using the resistance measuring section 15, gas detection can be performed with high precision. It can be carried out.
- the electrical resistance value of the conductor-containing porous body 20 changes significantly when it comes into contact with a specific gas.
- gas can be detected with high precision.
- the insulating porous body is any one of paper, thread, nonwoven fabric, cloth, and reed stick
- a conductor is added to the paper, thread, nonwoven fabric, cloth, and reed stick.
- the conductor-containing porous body 20 can be easily produced.
- the conductor-containing porous body 20 constituting the gas detection section can be brought into reliable contact with the gas to be measured, and the gas can be detected with high accuracy.
- the conductor-containing porous body 20 can be incinerated and disposed of, thereby reducing environmental load.
- the present invention is not limited to this, and can be modified as appropriate without departing from the technical idea of the invention.
- hydrogen gas is used as an example of the gas to be detected, but the present invention is not limited to this, and the gas to be detected may be oxygen gas or carbon dioxide gas.
- the insulating porous body is made of paper and a conductor-containing porous body (CNT-containing paper) is used, the present invention is not limited to this, and the insulating porous body is made of paper. It may be a conductor-containing porous body (e.g., CNT-containing thread), or a conductor-containing porous body (e.g., CNT-containing nonwoven fabric) made of an insulating porous body as a nonwoven fabric.
- the insulating porous body may be a conductor-containing porous body (e.g., CNT-containing cloth), or the insulating porous body may be a conductor-containing porous body (for example, a CNT-containing lead stick) as a lead stick. It may be.
- the conductor-containing porous body (CNT-containing thread) can be manufactured by the method shown below.
- the method for incorporating carbon nanotubes into yarn is basically the same as the method used for hand dyeing.
- a method is used in which the base thread is immersed in a carbon nanotube dispersion, the dispersion is heated (around 60 degrees Celsius) to a level that does not boil, and the water is evaporated so that the concentrated carbon nanotubes coat the thread. You can also do that. According to such an impregnation method, more carbon nanotubes are impregnated into the yarn.
- the base yarn (substrate) required to produce the CNT-containing yarn includes commonly used naturally derived yarns such as cotton yarn, hemp yarn, wool, and silk, or chemically synthesized polyester, Synthetic fiber yarns such as nylon are used, but mixed yarns of these may also be used.
- a CNT-containing yarn may be produced by applying a carbon nanotube dispersion to the surface and drying it.
- the gas sensor shown in this embodiment was placed in a closed container having a gas inlet and a gas outlet and having a volume of 6.5 ⁇ 10 ⁇ 3 m 3 .
- an ultrasonic humidifier and water heated to 80°C are prepared, and a distance of 1 cm from the mist outlet from the humidifier and a distance of 1 cm from the surface of the water heated to 80°C is used.
- Water vapor gas was brought into contact with the first electrode portion of the gas sensor.
- the gas shown in Table 1 (high purity gas with a purity of 95% or more) is introduced from the gas inlet at a rate of 2.0 ⁇ 10 -4 m 3 /sec, and the resistance measurement unit measures the resistance between the first electrode part and the second electrode part.
- the electrical resistance value between was measured. Gases for which there was a change in electrical resistance between the electrical resistance value 10 seconds after the start of gas introduction or contact with water vapor gas from the electrical resistance value before gas introduction were marked as "possible” for detection. .
- the evaluation results are shown in Table 1. Specifically, the rate of change in electrical resistance in hydrogen gas was 0.04%. In other words, the electrical resistance value increased by 0.04% due to the introduction of hydrogen gas. Further, the electrical resistance change rate in nitrogen gas was 0.00%.
- a gas sensor that has a simple structure, is low in manufacturing cost, is easy to handle, and is capable of detecting a specific gas.
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Abstract
Description
この発明は、特定のガスを検知するガスセンサに関するものである。
本願は、２０２２年８月２５日に、日本に出願された特願２０２２－１３４１７６号及び２０２３年８月１４日に、日本に出願された特願２０２３－１３２０２５号に基づき優先権を主張し、その内容をここに援用する。
The present invention relates to a gas sensor that detects a specific gas.
This application claims priority based on Japanese Patent Application No. 2022-134176 filed in Japan on August 25, 2022 and Japanese Patent Application No. 2023-132025 filed in Japan on August 14, 2023. Its contents are incorporated here.
従来、水素、酸素、二酸化炭素等の各種ガスを検知するためにガスセンサが用いられている。
例えば、特許文献１には、金属酸化物を用いた水素ガスセンサが提案されている。また、特許文献２には、固体電解質からなる酸素イオン伝導体を用いた酸素ガスセンサおよび二酸化炭素ガスセンサが提案されている。
Conventionally, gas sensors have been used to detect various gases such as hydrogen, oxygen, and carbon dioxide.
For example,
特許文献１に記載された水素ガスセンサにおいては、基板上に水素検知層が形成され、この水素検知層に一対の電極が配設された構造とされている。そして、水素検知層が、水素ガスをプロトンと電子とに解離させる触媒と、触媒による水素ガスの解離によって発生した電子によって電気抵抗が低下する金属酸化物とを含んでおり、一対の電極間の電気抵抗の変化により、水素ガスを検知する構成とされている。
The hydrogen gas sensor described in
特許文献２に記載された酸素ガスセンサおよび二酸化炭素ガスセンサにおいては、絶縁性の基板（例えばアルミナ製基板）の表面に固体電解質からなる酸素イオン伝導体が配設され、この酸素イオン伝導体に接するように貴金属製の酸素検出電極と、金属炭酸塩に覆われた二酸化炭素検出電極と、被検ガスから遮断された参照電極とを備えた構造とされている。
In the oxygen gas sensor and carbon dioxide gas sensor described in
ところで、特許文献１、２に記載された各種ガスセンサにおいては、ガスを検知する金属酸化物や固体電解質を基板の表面に配設していることから、形状の自由度が低く、かつ、構造が複雑である。このため、作製が困難であるとともに、取り扱いが容易ではないといった課題があった。
特に、特許文献１の水素ガスセンサにおいては、水素ガスをプロトンと電子とに解離させる触媒（例えばＴｉ）を配設する必要があり、作製コストが増大するといった問題があった。
By the way, in the various gas sensors described in
Particularly, in the hydrogen gas sensor of
この発明は、前述した事情に鑑みてなされたものであって、構造が簡単であって、作製コストが低く取り扱いが容易であり、特定のガスの検知が可能なガスセンサを提供することを目的とする。 The present invention was made in view of the above-mentioned circumstances, and an object thereof is to provide a gas sensor that has a simple structure, low manufacturing cost, easy handling, and is capable of detecting a specific gas. do.
上述の課題を解決するために、本発明の態様１のガスセンサは、絶縁多孔質体に導電体を含有させた導電体含有多孔質体と、前記導電体含有多孔質体の延在方向に間隔をあけて配設された第１電極部および第２電極部と、前記第１電極部と前記第２電極部との間の電気抵抗値を測定する抵抗測定部と、を備えており、前記導電体含有多孔質体がガスを検知するガス検知部とされていることを特徴としている。
In order to solve the above-mentioned problems, a gas sensor according to
本発明の態様１のガスセンサによれば、絶縁多孔質体に導電体を含有させた導電体含有多孔質体を有しており、この導電体含有多孔質体がガスを検知するガス検知部とされている。
ここで、絶縁多孔質体に導電体を含有させた導電体含有多孔質体においては、特定のガスと接触した際に電気抵抗値が変化することになる。よって、ガス検知部である導電体含有多孔質体に特定のガスが曝されると、導電体含有多孔質体の電気抵抗が変化することになるため、前記抵抗測定部によって、前記第１電極部と前記第２電極部との間の電気抵抗値を測定することにより、ガスの検知を行うことができる。
そして、絶縁多孔質体に導電体を含有させた導電体含有多孔質体を用いているので、カーボンナノチューブ等を配設する基板が不要となって構造が簡単であり、取り扱いが容易である。また、構造が簡単であるとともに触媒等が不要であることから、作製コストを大幅に削減することができる。
According to the first aspect of the present invention, the gas sensor has a conductor-containing porous body in which a conductor is contained in an insulating porous body, and the conductor-containing porous body serves as a gas detection portion for detecting gas. has been done.
Here, in a conductor-containing porous body in which a conductor is contained in an insulating porous body, the electrical resistance value changes when it comes into contact with a specific gas. Therefore, when a specific gas is exposed to the conductor-containing porous body, which is the gas detection section, the electrical resistance of the conductor-containing porous body changes. Gas can be detected by measuring the electrical resistance value between the electrode part and the second electrode part.
Further, since a conductor-containing porous body in which a conductor is contained in an insulating porous body is used, a substrate on which carbon nanotubes and the like are disposed is not required, resulting in a simple structure and easy handling. Furthermore, since the structure is simple and no catalyst or the like is required, manufacturing costs can be significantly reduced.
本発明の態様２のガスセンサは、態様１のガスセンサにおいて、前記導電体は、ゼーベック係数の絶対値が３μＶ／Ｋ以上の熱電材料であることを特徴としている。
本発明の態様２のガスセンサによれば、絶縁多孔質体に含有させる導電体がゼーベック係数の絶対値が３μＶ／Ｋ以上の熱電材料とされているので、導電体含有多孔質体は、特定のガスと接触した際に電気抵抗値が大きく変化することになり、前記抵抗測定部によって、前記第１電極部と前記第２電極部との間の電気抵抗値を測定することにより、ガスの検知を精度良く行うことができる。
A gas sensor according to a second aspect of the present invention is characterized in that in the gas sensor according to the first aspect, the conductor is a thermoelectric material having an absolute value of a Seebeck coefficient of 3 μV/K or more.
According to the gas sensor of the second aspect of the present invention, the conductor contained in the insulating porous body is a thermoelectric material with an absolute value of Seebeck coefficient of 3 μV/K or more, so the conductor-containing porous body has a specific The electrical resistance value changes greatly when it comes into contact with gas, and the gas can be detected by measuring the electrical resistance value between the first electrode part and the second electrode part using the resistance measuring part. can be performed with high precision.
本発明の態様３のガスセンサは、態様１または態様２のガスセンサにおいて、前記導電体は、カーボンナノチューブであることを特徴としている。
本発明の態様３のガスセンサによれば、絶縁多孔質体に含有させる導電体がカーボンナノチューブとされているので、導電体含有多孔質体は、特定のガスと接触した際に電気抵抗値が大きく変化することになり、前記抵抗測定部によって、前記第１電極部と前記第２電極部との間の電気抵抗値を測定することにより、ガスの検知を精度良く行うことができる。
A gas sensor according to
According to the gas sensor of
本発明の態様４のガスセンサは、態様１または態様２のガスセンサにおいて、前記導電体は、有機熱電材料であることを特徴としている。
本発明の態様４のガスセンサによれば、絶縁多孔質体に含有させる導電体が有機熱電材料とされているので、導電体含有多孔質体は、特定のガスと接触した際に電気抵抗値が大きく変化することになり、前記抵抗測定部によって、前記第１電極部と前記第２電極部との間の電気抵抗値を測定することにより、ガスの検知を精度良く行うことができる。
A gas sensor according to
According to the gas sensor of
本発明の態様５のガスセンサは、態様１または態様２のガスセンサにおいて、前記導電体が、化合物半導体またはシリコン半導体による、ナノチューブまたはナノワイヤであることを特徴としている。
本発明の態様５のガスセンサによれば、絶縁多孔質体に含有させる導電体が化合物半導体またはシリコン半導体による、ナノチューブまたはナノワイヤとされているので、導電体含有多孔質体は、特定のガスと接触した際に電気抵抗値が大きく変化することになり、前記抵抗測定部によって、前記第１電極部と前記第２電極部との間の電気抵抗値を測定することにより、ガスの検知を精度良く行うことができる。
A gas sensor according to a fifth aspect of the present invention is the gas sensor according to the first or second aspect, wherein the conductor is a nanotube or a nanowire made of a compound semiconductor or a silicon semiconductor.
According to the gas sensor of aspect 5 of the present invention, the conductor contained in the insulating porous body is a nanotube or nanowire made of a compound semiconductor or a silicon semiconductor, so that the conductor-containing porous body comes into contact with a specific gas. When this occurs, the electrical resistance value changes greatly, and by measuring the electrical resistance value between the first electrode part and the second electrode part using the resistance measuring part, gas detection can be performed with high precision. It can be carried out.
本発明の態様６のガスセンサは、態様１から態様５のいずれかひとつのガスセンサにおいて、前記絶縁多孔質体が、紙、糸、不織布、布、リードスティックのいずれか一種とされていることを特徴としている。
本発明の態様６のガスセンサによれば、前記絶縁多孔質体が、紙、糸、不織布、布、リードスティック（吸液芯）のいずれか一種とされているので、これら紙、糸、不織布、布、リードスティック（吸液芯）に導電体を含有させることで容易に導電体含有多孔質体を作製することができる。なお、本発明における紙は、抄紙により成形されるもの全般を含み、本発明における布は、紡織により成形されるもの全般を含む。
また、前記導電体含有多孔質体と測定対象のガスを確実に接触させることができ、ガスを精度良く検知することができる。
さらに、使用後には、前記導電体含有多孔質体を焼却して廃棄することができ、環境負荷を低減することができる。
The gas sensor according to aspect 6 of the present invention is the gas sensor according to any one of
According to the gas sensor according to aspect 6 of the present invention, the insulating porous body is made of any one of paper, thread, nonwoven fabric, cloth, and reed stick (liquid absorption core). A conductor-containing porous body can be easily produced by incorporating a conductor into cloth or a reed stick (liquid-absorbing core). Note that the paper in the present invention includes any paper formed by papermaking, and the cloth in the present invention includes any fabric formed by spinning.
Furthermore, the conductor-containing porous body can be brought into reliable contact with the gas to be measured, and the gas can be detected with high accuracy.
Furthermore, after use, the conductor-containing porous body can be incinerated and disposed of, reducing environmental load.
本発明の態様７は、態様１から態様６のいずれかひとつのガスセンサにおいて、前記ガス検知部で検知されるガスが水素ガスであることを特徴としている。
本発明の態様７のガスセンサによれば、前記ガス検知部で検知されるガスが水素ガスとされているので、前記抵抗測定部によって前記第１電極部と前記第２電極部との間の電気抵抗値を測定することにより、水素ガスの検知を行うことができる。
A seventh aspect of the present invention is characterized in that, in the gas sensor according to any one of
According to the gas sensor according to aspect 7 of the present invention, since the gas detected by the gas detection section is hydrogen gas, the resistance measurement section detects an electric current between the first electrode section and the second electrode section. Hydrogen gas can be detected by measuring the resistance value.
本発明の態様８は、態様１から態様６のいずれかひとつのガスセンサにおいて、前記ガス検知部で検知されるガスが酸素ガスであることを特徴としている。
本発明の態様８のガスセンサによれば、前記ガス検知部で検知されるガスが酸素ガスとされているので、前記抵抗測定部によって前記第１電極部と前記第２電極部との間の電気抵抗値を測定することにより、酸素ガスの検知を行うことができる。
Aspect 8 of the present invention is characterized in that in the gas sensor according to any one of
According to the gas sensor according to aspect 8 of the present invention, since the gas detected by the gas detection section is oxygen gas, the resistance measurement section detects an electric current between the first electrode section and the second electrode section. Oxygen gas can be detected by measuring the resistance value.
本発明の態様９は、態様１から態様６のいずれかひとつのガスセンサにおいて、前記ガス検知部で検知されるガスが二酸化炭素ガスであることを特徴としている。
本発明の態様９のガスセンサによれば、前記ガス検知部で検知されるガスが二酸化炭素ガスとされているので、前記抵抗測定部によって前記第１電極部と前記第２電極部との間の電気抵抗値を測定することにより、二酸化炭素ガスの検知を行うことができる。
A ninth aspect of the present invention is characterized in that, in the gas sensor according to any one of
According to the gas sensor according to aspect 9 of the present invention, since the gas detected by the gas detection section is carbon dioxide gas, the resistance measurement section detects the difference between the first electrode section and the second electrode section. Carbon dioxide gas can be detected by measuring the electrical resistance value.
本発明の態様１０は、態様１から態様６のいずれかひとつのガスセンサにおいて、前記ガス検知部で検知されるガスが水蒸気ガスであることを特徴としている。
本発明の態様１０のガスセンサによれば、前記ガス検知部で検知されるガスが水蒸気ガスとされているので、前記抵抗測定部によって前記第１電極部と前記第２電極部との間の電気抵抗値を測定することにより、水蒸気ガスの検知を行うことができる。
A tenth aspect of the present invention is characterized in that, in the gas sensor according to any one of aspects one to six, the gas detected by the gas detection section is water vapor gas.
According to the gas sensor according to
本発明によれば、構造が簡単であって、作製コストが低く取り扱いが容易であり、特定のガスの検知が可能なガスセンサを提供することができる。 According to the present invention, it is possible to provide a gas sensor that has a simple structure, is low in manufacturing cost, is easy to handle, and is capable of detecting a specific gas.
以下に、本発明の実施形態について添付した図面を参照して説明する。なお、以下に示す各実施形態は、発明の趣旨をより良く理解させるために具体的に説明するものであり、特に指定のない限り、本発明を限定するものではない。また、以下の説明で用いる図面は、本発明の特徴をわかりやすくするために、便宜上、要部となる部分を拡大して示している場合があり、各構成要素の寸法比率などが実際と同じであるとは限らない。 Embodiments of the present invention will be described below with reference to the attached drawings. It should be noted that each of the embodiments shown below will be specifically described in order to better understand the gist of the invention, and unless otherwise specified, the embodiments are not intended to limit the invention. Furthermore, in order to make the features of the present invention easier to understand, the drawings used in the following explanation may show important parts enlarged for convenience, and the dimensional ratio of each component may be the same as the actual one. Not necessarily.
本発明の実施形態であるガスセンサ１０は、図１に示すように、絶縁多孔質体に導電体を含有させた導電体含有多孔質体２０と、この導電体含有多孔質体２０の延在方向に間隔をあけて配設された第１電極部１１および第２電極部１２と、第１電極部１１と第２電極部１２との間の電気抵抗を測定する抵抗測定部１５と、を備えている。本実施形態では、導電体含有多孔質体２０の一端（図１において下端）に第１電極部１１が配設され、導電体含有多孔質体２０の他端（図１において上端）に第２電極部１２が配設されている。
そして、本実施形態では、上述の導電体含有多孔質体２０が特定のガスを検知するガス検知部とされている。
As shown in FIG. 1, a
In this embodiment, the conductor-containing
ここで、ガス検知部で検知される特定のガスとしては、例えば、水素ガス、酸素ガス、二酸化炭素ガス等が挙げられる。
本実施形態においては、検知対象のガスを水素ガスとしており、ガスセンサ１０は、水素ガスを検知する水素ガスセンサとされている。
Here, examples of the specific gas detected by the gas detection unit include hydrogen gas, oxygen gas, carbon dioxide gas, and the like.
In this embodiment, the gas to be detected is hydrogen gas, and the
導電体含有多孔質体２０は、絶縁多孔質体に導電体を含有させたものとされている。
ここで、本実施形態においては、導電体は、ゼーベック係数の絶対値が３μＶ／Ｋ以上の熱電材料であることが好ましい。この熱電材料は、半導体としての特性を有しており、ｐ型半導体又はｎ型半導体としての特性を有している。なお、本実施形態においては、導電体含有多孔質体２０は、ｐ型半導体又はｎ型半導体のいずれであってもよい。
The conductor-containing
Here, in this embodiment, the conductor is preferably a thermoelectric material having an absolute value of the Seebeck coefficient of 3 μV/K or more. This thermoelectric material has properties as a semiconductor, and has properties as a p-type semiconductor or an n-type semiconductor. In addition, in this embodiment, the conductor-containing
ゼーベック係数の絶対値が３μＶ／Ｋ以上の熱電材料としては、（ａ）カーボンナノチューブ（ＣＮＴ）、（ｂ）有機熱電材料、（ｃ）化合物半導体またはシリコン半導体によるナノチューブやナノワイヤ、（ｄ）貴金属化合物、（ｅ）カーボン材料、（ｆ）Ｂｉ、Ｃｏ、Ｆｅ、Ｎｉ等の金属、などが挙げられる。
なお、導電体含有多孔質体２０に含まれる熱電材料は、ゼーベック係数の絶対値が４０μＶ／Ｋ以上であることが好ましい。また、（ａ）から（ｆ）の熱電材料を複合化させて用いても良い。
Thermoelectric materials with an absolute value of Seebeck coefficient of 3 μV/K or more include (a) carbon nanotubes (CNTs), (b) organic thermoelectric materials, (c) nanotubes and nanowires made of compound semiconductors or silicon semiconductors, and (d) noble metal compounds. , (e) carbon material, (f) metal such as Bi, Co, Fe, Ni, etc.
Note that the thermoelectric material contained in the conductor-containing
ここで、（ａ）カーボンナノチューブにおいては、絶縁多孔質体にカーボンナノチューブを含有させることで、導電体含有多孔質体２０を構成することができる。
なお、カーボンナノチューブのゼーベック係数は５～１７０μＶ／Ｋ程度である。
Here, regarding (a) carbon nanotubes, the conductor-containing
Note that the Seebeck coefficient of carbon nanotubes is approximately 5 to 170 μV/K.
（ｂ）有機熱電材料としては、ＰＥＤＯＴ系（ＰＥＤＯＴ：ＰＳＳ、ＰＥＤＯＴ：Ｔｏｓ等）、π共役ニッケル錯体系（ｐｏｌｙ（ｎｉｃｋｅｌ－ｅｔｈｙｌｅｎｅｔｅｔｒａｔｈｉｏｌａｔｅ）、Ｎ－ＤＭＢＩ系（Ｎ、Ｎ－ｄｉｍｅｔｈｙｌ－２－ｐｈｅｎｙｌ－２、３－ｄｉｈｙｄｒｏ－１Ｈ－ｂｅｎｚｏｉｍｉｄａｚｏｌｅ）等が挙げられる。
なお、ＰＥＤＯＴ：ＰＳＳのゼーベック係数は１０～１００μＶ／Ｋ程度である。また、ＰＥＤＯＴ：Ｔｏｓのゼーベック係数は４０～２１０μＶ／Ｋ程度である。π共役ニッケル錯体系のゼーベック係数は－１６～－１４０μＶ／Ｋ程度である。
有機熱電材料においては、絶縁多孔質体に有機熱電材料を含有させることで、導電体含有多孔質体２０を構成することができる。
(b) Examples of organic thermoelectric materials include PEDOT type (PEDOT:PSS, PEDOT:Tos, etc.), π-conjugated nickel complex type (poly(nickel-ethylenetetrathiolate)), N-DMBI type (N,N-dimethyl-2-phenyl- 2,3-dihydro-1H-benzoimidazole) and the like.
Note that the Seebeck coefficient of PEDOT:PSS is approximately 10 to 100 μV/K. Further, the Seebeck coefficient of PEDOT:Tos is about 40 to 210 μV/K. The Seebeck coefficient of the π-conjugated nickel complex system is about -16 to -140 μV/K.
In the organic thermoelectric material, the conductor-containing
（ｃ）化合物半導体またはシリコン半導体によるナノチューブやナノワイヤにおいては、他の多孔質体に窒化ホウ素ナノチューブや、ＳｉナノワイヤやＢｉ２Ｔｅ３Ｂｉ２Ｔｅ３ナノワイヤなどの化合物半導体またはシリコン半導体からなるナノチューブまたはナノワイヤを１種類以上含有させることで、導電体含有多孔質体２０を構成することができる。
(c) Nanotubes or nanowires made of compound semiconductors or silicon semiconductors include nanotubes or nanowires made of compound semiconductors or silicon semiconductors such as boron nitride nanotubes, Si nanowires, Bi 2 Te 3 Bi 2 Te 3 nanowires, etc. in other porous bodies. By containing one or more types of, the conductor-containing
（ｄ）貴金属化合物としては、銅化合物、銀化合物、金化合物、白金化合物等が挙げられる。具体的には、貴金属元素（Ｃｕ、Ａｇ、Ａｕ、Ｐｔ）と、Ｓ、Ｓｅ、Ｔｅの化合物であることが好ましい。
貴金属化合物においては、絶縁多孔質体に貴金属化合物を含有させることで、導電体含有多孔質体２０を構成することができる。
(d) Examples of the noble metal compound include copper compounds, silver compounds, gold compounds, platinum compounds, and the like. Specifically, a compound of a noble metal element (Cu, Ag, Au, Pt) and S, Se, Te is preferable.
Regarding the noble metal compound, the conductor-containing
（ｅ）カーボン材料としては、カーボンブラック、グラファイト等が挙げられる。
カーボン材料においては、絶縁多孔質体にカーボン材料を含有させることで、導電体含有多孔質体２０を構成することができる。
(e) Examples of carbon materials include carbon black and graphite.
In the case of carbon material, the conductor-containing
（ｆ）Ｂｉ、Ｃｏ、Ｆｅ、Ｎｉ等の金属においては、絶縁多孔質体にＢｉ、Ｃｏ、Ｆｅ、Ｎｉ等の金属を含有させることで、導電体含有多孔質体２０を構成することができる。なお、めっき法によってＢｉ、Ｃｏ、Ｆｅ、Ｎｉ等の金属を絶縁多孔質体に含有させることが好ましい。
(f) In the case of metals such as Bi, Co, Fe, and Ni, the conductor-containing
本実施形態においては、導電体含有多孔質体２０は、絶縁多孔質体にカーボンナノチューブ（ＣＮＴ）が含浸されたものであり、半導体としての特性を有しており、ｐ型半導体又はｎ型半導体としての特性を有している。なお、本実施形態においては、導電体含有多孔質体２０は、ｐ型半導体又はｎ型半導体のいずれであってもよい。
In this embodiment, the conductor-containing
絶縁多孔質体としては、紙、糸、不織布、布、リードスティック等の繊維質のものが好ましい。本実施形態においては、絶縁多孔質体は紙とされており、導電体含有多孔質体２０は、ＣＮＴ含有紙とされている。つまり、絶縁多孔質体として絶縁体である紙を用いた。
また、繊維としては天然繊維でもよく、人工繊維でもよい。複数の繊維を組み合わせた紙、糸、不織布、布、リードスティック等を用いてもよい。
ここで、導電体含有多孔質体２０（ＣＮＴ含有紙）の製造方法の一例について、図２を参照して説明する。
The insulating porous material is preferably a fibrous material such as paper, thread, nonwoven fabric, cloth, or reed stick. In this embodiment, the insulating porous body is paper, and the conductor-containing
Further, the fibers may be natural fibers or artificial fibers. Paper, thread, nonwoven fabric, cloth, reed stick, etc. that are a combination of multiple fibers may be used.
Here, an example of a method for manufacturing the conductor-containing porous body 20 (CNT-containing paper) will be described with reference to FIG. 2.
図２（１）に示すように、純水にパルプ繊維を投入して十分に撹拌することにより、パルプ繊維が分散したパルプ懸濁液５１を得る。
また、図２（２）に示すように、純水に単層カーボンナノチューブを投入して十分撹拌することにより、カーボンナノチューブ分散液５２を得る。このとき、単層カーボンナノチューブは、紙原料であるパルプ繊維の重さに対して０．８質量％以上３．２質量％以下の割合とすることが好ましい。また、分散剤を添加する必要はない。また、カーボンナノチューブ分散液５２を得る際には、超音波処理を３０分間程度行うことが好ましい。
As shown in FIG. 2(1), pulp fibers are added to pure water and sufficiently stirred to obtain a
Further, as shown in FIG. 2(2), a carbon
次に、図２（３）に示すように、上述のパルプ懸濁液５１とカーボンナノチューブ分散液５２とを混合して攪拌することによって混合液５３を得る。このとき、パルプ繊維にカーボンナノチューブが付着することになる。
そして、図２（４）、（５）に示すように、上述の混合液５３を紙漉きして乾燥させることにより、導電体含有多孔質体２０（ＣＮＴ含有紙）を得る。
Next, as shown in FIG. 2(3), the above-described
Then, as shown in FIGS. 2(4) and 2(5), the above-mentioned
本実施形態であるガスセンサ１０においては、ガス検知部を構成する導電体含有多孔質体２０が水素ガスに曝されると、導電体含有多孔質体２０と水素ガスとが接触することにより、導電体含有多孔質体２０の電気抵抗値が上昇することになる。
そこで、抵抗測定部１５によって、第１電極部１１と第２電極部１２との間の電気抵抗値を測定しておき、電気抵抗値が上昇した際に、水素ガスが存在すると判断する。
In the
Therefore, the electrical resistance value between the
以上のような構成とされた本実施形態であるガスセンサ１０においては、絶縁多孔質体に導電体を含有させた導電体含有多孔質体２０を用いており、この導電体含有多孔質体２０がガスを検知するガス検知部とされていることから、ガス検知部である導電体含有多孔質体２０が水素ガスに曝された際に、導電体含有多孔質体２０の電気抵抗が変化することになる。
したがって、抵抗測定部１５により第１電極部１１と第２電極部１２との間の電気抵抗値を測定することによって、水素ガスの検知を行うことができる。
In the
Therefore, hydrogen gas can be detected by measuring the electrical resistance value between the
また、本実施形態であるガスセンサ１０においては、ガス検知部を構成する導電体含有多孔質体２０が導電体を絶縁多孔質体に含有させたものとされているので、カーボンナノチューブ等を配設する基板が不要となって構造が簡単となり、取り扱いが容易である。また、構造が簡単であるとともに触媒等が不要であることから、作製コストを大幅に削減することができる。
In addition, in the
また、本実施形態であるガスセンサ１０において、導電体が、ゼーベック係数の絶対値が３μＶ／Ｋ以上の熱電材料とされている場合には、導電体含有多孔質体２０は、特定のガスと接触した際に電気抵抗値が大きく変化することになり、抵抗測定部１５によって、第１電極部１１と第２電極部１２との間の電気抵抗値を測定することにより、ガスの検知を精度良く行うことができる。
In addition, in the
さらに、本実施形態であるガスセンサ１０において、導電体が、カーボンナノチューブとされている場合には、導電体含有多孔質体２０は、特定のガスと接触した際に電気抵抗値が大きく変化することになり、抵抗測定部１５によって、第１電極部１１と第２電極部１２との間の電気抵抗値を測定することにより、ガスの検知を精度良く行うことができる。
Furthermore, in the
また、本実施形態であるガスセンサ１０において、絶縁多孔質体が、紙、糸、不織布、布、リードスティックのいずれか一種である場合には、紙、糸、不織布、布、リードスティックに導電体を含有させることで容易に導電体含有多孔質体２０を作製することができる。
さらに、ガス検知部を構成する導電体含有多孔質体２０と測定対象のガスを確実に接触させることができ、ガスを精度良く検知することができる。
さらに、使用後には、導電体含有多孔質体２０を焼却して廃棄することができ、環境負荷を低減することができる。
Further, in the
Furthermore, the conductor-containing
Furthermore, after use, the conductor-containing
以上、本発明の一実施形態について説明したが、本発明はこれに限定されることはなく、その発明の技術的思想を逸脱しない範囲で適宜変更可能である。
例えば、本実施形態においては、検知するガスとして水素ガスを例に挙げて説明したが、これに限定されることはなく、検知するガスを酸素ガスとしてもよいし、二酸化炭素ガスとしてもよい。
Although one embodiment of the present invention has been described above, the present invention is not limited to this, and can be modified as appropriate without departing from the technical idea of the invention.
For example, in the present embodiment, hydrogen gas is used as an example of the gas to be detected, but the present invention is not limited to this, and the gas to be detected may be oxygen gas or carbon dioxide gas.
また、本実施形態においては、絶縁多孔質体を紙とした導電体含有多孔質体（ＣＮＴ含有紙）を用いるものとして説明したが、これに限定されることはなく、絶縁多孔質体を糸とした導電体含有多孔質体（例えば、ＣＮＴ含有糸）であってもよいし、絶縁多孔質体を不織布とした導電体含有多孔質体（例えば、ＣＮＴ含有不織布）であってもよいし、絶縁多孔質体を布とした導電体含有多孔質体（例えば、ＣＮＴ含有布）であってもよく、絶縁多孔質体をリードスティックとした導電体含有多孔質体（例えば、ＣＮＴ含有リードスティック）であってもよい。
なお、導電体含有多孔質体（ＣＮＴ含有糸）は、以下に示す手法によって製造することができる。
Furthermore, in this embodiment, although the insulating porous body is made of paper and a conductor-containing porous body (CNT-containing paper) is used, the present invention is not limited to this, and the insulating porous body is made of paper. It may be a conductor-containing porous body (e.g., CNT-containing thread), or a conductor-containing porous body (e.g., CNT-containing nonwoven fabric) made of an insulating porous body as a nonwoven fabric. The insulating porous body may be a conductor-containing porous body (e.g., CNT-containing cloth), or the insulating porous body may be a conductor-containing porous body (for example, a CNT-containing lead stick) as a lead stick. It may be.
Note that the conductor-containing porous body (CNT-containing thread) can be manufactured by the method shown below.
カーボンナノチューブの糸への含有方法については、基本的には手工染色等の手法と同様である。ベースとなる糸をカーボンナノチューブ分散液に浸し、この状態で分散液を沸騰しない程度に加熱（６０℃前後）し、水分を飛ばすことで濃縮されたカーボンナノチューブが糸をコーティングするような手法を取ることもできる。このような含浸法によれば、より多くのカーボンナノチューブが糸に含浸される。 The method for incorporating carbon nanotubes into yarn is basically the same as the method used for hand dyeing. A method is used in which the base thread is immersed in a carbon nanotube dispersion, the dispersion is heated (around 60 degrees Celsius) to a level that does not boil, and the water is evaporated so that the concentrated carbon nanotubes coat the thread. You can also do that. According to such an impregnation method, more carbon nanotubes are impregnated into the yarn.
なお、ＣＮＴ含有糸を作製するのに必要なベースとなる糸（基材）には、一般的に使用されている綿糸、麻糸、羊毛、絹等の自然由来の糸もしくは化学合成由来のポリエステル、ナイロン等の合成繊維糸が用いられるが、これらの混合糸が用いられてもよい。
ここで、合成繊維のように染料が染みこまないタイプの糸については、その表面にカーボンナノチューブ分散液を塗布して、乾燥させることにより、ＣＮＴ含有糸を作製してもよい。
Note that the base yarn (substrate) required to produce the CNT-containing yarn includes commonly used naturally derived yarns such as cotton yarn, hemp yarn, wool, and silk, or chemically synthesized polyester, Synthetic fiber yarns such as nylon are used, but mixed yarns of these may also be used.
Here, for a type of yarn that is not impregnated with dye, such as synthetic fiber, a CNT-containing yarn may be produced by applying a carbon nanotube dispersion to the surface and drying it.
以下に、本発明の効果を確認すべく行った確認実験の結果について説明する。 Below, the results of a confirmation experiment conducted to confirm the effects of the present invention will be explained.
本実施形態に示すガスセンサを、ガス導入口とガス放出口を有するとともに、容積６．５×１０－３ｍ３とされた密閉容器内に配置した。水蒸気ガスの検知の実施形態は、超音波式加湿器および８０℃に加熱した水を用意し、加湿器からのミスト出口から１ｃｍの距離および８０℃に加熱した水の液面から１ｃｍの距離にガスセンサの第１電極部に水蒸気ガスを接触させた。
ガス導入口から表１に示すガス（純度が９５％以上の高純度ガス）を２．０×１０－４ｍ３／ｓｅｃで導入し、抵抗測定部によって第１電極部と第２電極部との間の電気抵抗値を測定した。そして、ガスの導入開始、または水蒸気ガスの接触時から１０秒後における電気抵抗値とガス導入前の電気抵抗値からの電気抵抗の変化があったガスは、検知の可否を「可」とした。評価結果を表１に示す。
具体的には、水素ガスにおける電気抵抗変化率は、０．０４％であった。つまり、水素ガス導入によって電気抵抗値が０．０４％上昇した。また、窒素ガスにおける電気抵抗変化率は、０．００％であった。
The gas sensor shown in this embodiment was placed in a closed container having a gas inlet and a gas outlet and having a volume of 6.5×10 −3 m 3 . In the embodiment of water vapor gas detection, an ultrasonic humidifier and water heated to 80°C are prepared, and a distance of 1 cm from the mist outlet from the humidifier and a distance of 1 cm from the surface of the water heated to 80°C is used. Water vapor gas was brought into contact with the first electrode portion of the gas sensor.
The gas shown in Table 1 (high purity gas with a purity of 95% or more) is introduced from the gas inlet at a rate of 2.0×10 -4 m 3 /sec, and the resistance measurement unit measures the resistance between the first electrode part and the second electrode part. The electrical resistance value between was measured. Gases for which there was a change in electrical resistance between the
Specifically, the rate of change in electrical resistance in hydrogen gas was 0.04%. In other words, the electrical resistance value increased by 0.04% due to the introduction of hydrogen gas. Further, the electrical resistance change rate in nitrogen gas was 0.00%.
表１に示すように、水素ガスを導入した場合には、水素ガスの導入に伴って電気抵抗値が上昇していることが確認される。よって、抵抗測定部において第１電極部と第２電極部との間の電気抵抗値を測定することで水素ガスを検知することが可能となる。
なお、窒素ガスを導入した場合には、窒素ガスの導入に伴う電気抵抗値の変化は認められなかった。このため、窒素ガスの検知はできない。
As shown in Table 1, when hydrogen gas was introduced, it was confirmed that the electrical resistance value increased with the introduction of hydrogen gas. Therefore, hydrogen gas can be detected by measuring the electrical resistance value between the first electrode part and the second electrode part in the resistance measurement part.
Note that when nitrogen gas was introduced, no change in electrical resistance was observed due to the introduction of nitrogen gas. Therefore, nitrogen gas cannot be detected.
また、表１に示すように、酸素ガスを導入した場合には、酸素ガスの導入に伴って電気抵抗値が変化していることが確認される。よって、抵抗測定部において第１電極部と第２電極部との間の電気抵抗値を測定することで酸素ガスを検知することが可能となる。
さらに、二酸化炭素ガスを導入した場合には、二酸化炭素ガスの導入に伴って電気抵抗値が変化していることが確認される。よって、抵抗測定部において第１電極部と第２電極部との間の電気抵抗値を測定することで二酸化炭素ガスを検知することが可能となる。
一方で、水蒸気ガスを接触させた場合には、水蒸気ガスの接触に伴って電気抵抗値が変化していることが確認される。よって、抵抗測定部において第１電極部と第２電極部との間の電気抵抗値を測定することで水蒸気ガスを検知することが可能となる。
Further, as shown in Table 1, when oxygen gas was introduced, it was confirmed that the electrical resistance value changed with the introduction of oxygen gas. Therefore, oxygen gas can be detected by measuring the electrical resistance value between the first electrode part and the second electrode part in the resistance measurement part.
Furthermore, when carbon dioxide gas is introduced, it is confirmed that the electrical resistance value changes with the introduction of carbon dioxide gas. Therefore, carbon dioxide gas can be detected by measuring the electrical resistance value between the first electrode part and the second electrode part in the resistance measurement part.
On the other hand, when water vapor gas is brought into contact, it is confirmed that the electrical resistance value changes with the contact with water vapor gas. Therefore, water vapor gas can be detected by measuring the electrical resistance value between the first electrode part and the second electrode part in the resistance measuring part.
以上のことから、本発明によれば、構造が簡単であって、作製コストが低く取り扱いが容易であり、特定のガスの検知が可能なガスセンサを提供可能である。 From the above, according to the present invention, it is possible to provide a gas sensor that has a simple structure, is low in manufacturing cost, is easy to handle, and is capable of detecting a specific gas.
１０ ガスセンサ
１１ 第１電極部
１２ 第２電極部
１５ 抵抗測定部
２０ 導電体含有多孔質体
10
Claims (10)
前記導電体含有多孔質体がガスを検知するガス検知部とされていることを特徴とするガスセンサ。 a conductor-containing porous body in which an electric conductor is contained in an insulating porous body; a first electrode portion and a second electrode portion disposed at intervals in an extending direction of the conductor-containing porous body; a resistance measuring section that measures an electrical resistance value between the first electrode section and the second electrode section;
A gas sensor characterized in that the conductor-containing porous body serves as a gas detection section that detects gas.
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