Gas sensing material and its manufacturing method

Abstract

To provide a gas sensing material with excellent sensing performance.SOLUTION: A gas sensing material includes a compound represented by the following formula and a carbon material.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a gas sensing material and a method for producing the same. Related Art This application claims domestic priority under Article 41 of the Japanese Patent Law based on Japanese Patent Application No. 2020-030315 (filing date: February 26, 2020 (Reiwa 2)), and the present invention is based on the contents disclosed in that patent application. For reference, the contents described in the specification and drawings of that patent application are incorporated herein by reference. [Background technology]

[0002] Gas sensing materials are used in various fields such as production environment, living environment, medical and health environment, pollution, drugs, etc. In particular, gas sensing materials are attracting increasing attention as a technology for detecting and monitoring gases harmful to animals and plants, detecting and sensing VOCG (Volatile Organic Compounds Gas) in living environments (indoor environments), medical and health environments, and storage environments of home appliances (refrigerators, air purifiers, etc.), and for health monitoring.

[0003] In recent years, gas sensing materials adapted to various fields and environments have been proposed. For example, 1) semiconducting metal oxides, such as SnO2 and TiO2, are the most widely used sensing materials, and are used in the high temperature range (300°C or higher). 2) Conductive polymers, such as polypyrrole (PPy), polyaniline (PANI), polythiophene (PTH), etc., can be used at around room temperature (about 25°C), and are easy to design and process. For example, Non-Patent Document 1 "Fabrication of polypyrrole-phenylalanine nano-films with NH3 gas sensitivity" discloses a polypyrrole (PPy) film complexed with phenylalanine that exhibits ammonia sensitivity, and a method for synthesizing the same. 3) Organic semiconductors (e.g., phthalocyanine) are also known as semiconductor materials.

[0004] In recent years, in the field of gas sensing, there has been a demand for gas sensing materials and methods for producing the same that are highly sensitive, highly selective, and capable of being used at low to normal temperatures, in the presence of moisture, and under humid conditions, as well as being flexible, thin, compact, easy to use, and inexpensive.

[0005] Therefore, there is still a demand for development of a gas sensing material having excellent and diverse functions and a simple and inexpensive method for manufacturing the gas sensing material. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] "Fabrication of polypyrrole-phenylalanine nano-films with NH3 gas sensitivity" (Jin-Yeol Kim et.al, Sensors and Actuators B: Chemical; Volume 153, Issue 2, 20 April 2011, Pages 421-426) Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention provides a gas sensing material having high sensitivity, high selectivity and wide range of applicability, and a method for producing the same. [Means for solving the problem]

[0008] [One aspect of the present invention] The present invention proposes the following as one aspect thereof. [1] A gas sensing material comprising: A gas sensing material comprising a polypyrrole derivative represented by the following chemical formula I and a carbon material. [ka] [wherein, in the above chemical formula I, A is an alkyl group having 1 to 10 carbon atoms or a phenyl group, B is a hydrogen atom, a halogen atom or a halogen compound; S is a sulfur atom, a nitrogen atom, an oxygen atom, or a polar compound composed of these atoms, A, B, and S are different substances; n is between 100 and 100,000. [2] A gas sensing material comprising: The film comprises at least a first layer and a second layer, Either the first layer or the second layer comprises a polypyrrole derivative represented by the following [chemical formula I], The gas sensing material, wherein the other of the first layer or the second layer comprises a carbon material. [ka] [wherein, in the above chemical formula I, A is an alkyl group having 1 to 10 carbon atoms or a phenyl group, B is a hydrogen atom, a halogen atom or a halogen compound; S is a sulfur atom, a nitrogen atom, an oxygen atom, or a polar compound composed of these atoms, A, B, and S are different substances; n is between 100 and 100,000. [3] The gas sensing material according to [1] or [2], wherein the carbon material is one or a combination of two or more selected from the group consisting of natural or synthetic (cubic crystal system) diamond, lonsdaleite, graphite, amorphous carbon, glassy carbon, graphene, fullerene, carbon nanotube, carbon nanohorn, carbon nanobud, carbon nanofiber, carbon nanofoam, and carbyne. [4] The gas sensing material according to any one of [1] to [3], wherein the compound represented by [Chemical Formula I] and the carbon material are bonded directly or via a bonding group. [5] The bonding group is a divalent bonding group, and is selected from the group consisting of -(C2)m (m is 1 or more and 10 or less)-, -O-, -S-, -OCH2-, -CHO-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NH-, -NH-CO-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CH=CH-COO-, -CH=CH-OCO-, and -COO-CH=CH The gas sensing material according to [5], which is one or a combination of two or more selected from the group consisting of -, -OCO-CH=CH-, -COO-CH2CH2-, -OCO-CH2CH2-, -CH2CH2-COO-, -CH2CH2-OCO-, -COO-CH2-, -OCO-CH2-, -CH2-COO-, -CH2-OCO-, -CH=CH-, -N=N-, -CH=NN=CH-, -CF=CF-, and -C≡C-. [6] A gas sensing material comprising: A gas sensing material having a structure of a polypyrrole derivative and carbon nanotubes, represented by the following chemical formula II. [ka] [wherein, in the above chemical formula II, A is an alkyl group having 1 to 10 carbon atoms or a phenyl group, B is a hydrogen atom, a halogen atom or a halogen compound; S is a sulfur atom, a nitrogen atom, an oxygen atom, or a polar compound composed of these atoms, A, B, and S are different substances; n is between 100 and 100,000. [7] The gas sensing material according to any one of [1] to [6], wherein the gas is a nitrogen-based compound, an alcohol, a ketone, or an aldehyde. [8] The gas-sensing material according to any one of [1] to [6], wherein the gas is a thiol compound. [9] A gas sensing material comprising: The gas is ammonia, In the above [Chemical Formula I] and the above [Chemical Formula II], A is a phenyl group; B is a hydrogen atom, a halogen atom or a halogen compound; S is a nitrogen atom or a nitrogen-containing functional group; A, B, and S are different substances; The gas sensing material according to any one of [1] to [6], wherein n is 100 or more and 100,000 or less.

[10] A gas sensing material comprising: The gas is acetone, In the above [Chemical Formula I] and [Chemical Formula II], A is a methyl group or an oxygen atom; B is a hydrogen atom or a sulfur atom; S is -OH 2+ , -OH or -COOH; A, B, and S are different substances; The gas sensing material according to any one of [1] to [6], wherein n is 100 to 100,000.

[11] The gas sensing material according to any one of [1] to

[10] , which senses at 1 atmospheric pressure and a relative humidity of 10% or more and 100% or less.

[12] A gas sensing material comprising: The present invention has a structure of a polypyrrole derivative and carbon nanotubes represented by the following chemical formula III: The gas sensing material, wherein the gas is acetone, ammonia, formaldehyde, or methyl mercaptan. [ka] [Chemical formula III]

[13] A gas sensing material comprising: The present invention has a structure of a polypyrrole derivative and carbon nanotubes represented by the following [chemical formula IV], The gas sensing material, wherein the gas is acetone. [ka]

[14] The gas sensing material according to any one of [1] to

[13] , which senses at 1 atmospheric pressure and at a temperature of -50°C or more and 100°C or less.

[15] A gas sensor comprising: The device comprises a positive electrode, a negative electrode, and a gas sensing material, The gas sensor, wherein the gas sensing material is as described in any one of [1] to

[14] .

[16] A method for producing a gas sensing material, comprising the steps of: (S1) preparing a conjugated polymer monomer, a carbon material, a transition metal salt catalyst, an emulsifier and / or a dispersant, and a functional organic substance; (S2) A dispersion liquid is obtained by mixing a carbon material, a transition metal salt, and an emulsifier and / or a dispersant, (S3) adding the conjugated polymer monomer and the functional organic substance to the dispersion liquid and emulsion-polymerizing the mixture; (S4) A production method comprising purifying and separating the polymerization product to obtain the gas sensing material.

[17] The gas sensing material according to any one of [1] to

[14] , The gas sensing material is (S1) preparing a conjugated polymer monomer, a carbon material, a transition metal salt catalyst, an emulsifier and / or a dispersant, and a functional organic substance; (S2) A dispersion liquid is obtained by mixing a carbon material, a transition metal salt, and an emulsifier and / or a dispersant, (S3) adding the conjugated polymer monomer and the functional organic substance to the dispersion liquid and emulsion-polymerizing the mixture; (S4) A gas sensing material obtained by purifying and separating the polymerization product. Effect of the Invention

[0009] The gas sensing material according to the present invention can achieve high sensitivity, high selectivity, wide range of use flexibility, miniaturization, and low power consumption.

[0010] In particular, the gas sensing material according to the present invention is configured as a nano-sized particle or rod-shaped body and senses a specific gas with high selectivity. In addition, since the functional groups A, B, and S (also called gas sensing functional groups) in the following chemical formula I are bonded to the carbon material, it is possible to improve the sensitivity to the specific gas.

[0011] In addition, the gas sensing material of the present invention can be easily formed into a thin film, and as a gas sensing thin film material, it has sufficient conductivity and is sensitive enough to detect trace amounts of gas components even with a resistance of a minute current of about a few μA.

[0012] Furthermore, the presence of the gas sensing functional group provides high selectivity to a specific gas component, and has the function of being able to sense even a very small amount of gas component of 1 PPM or less. The gas sensing material according to the present invention can exhibit gas sensing properties in a low to high temperature range, for example, from -50°C to 150°C, particularly at temperatures in general use (0°C to 40°C, particularly around room temperature of about 25°C). The gas sensing material according to the present invention can exhibit the effect of maintaining stable sensing performance even under high humidity conditions (relative humidity of 10% to 100%). In addition, since these nanosensing structures exist in a state of being dispersed in an aqueous solution or an organic solvent such as alcohol, they can be easily cast onto a substrate, and are convenient in the processing step in that a thin film can be easily produced.

[0013] According to the manufacturing method of the present invention, it is possible to obtain a gas sensing material that is simple, compact, and inexpensive. In particular, according to the manufacturing method of the present invention, functional groups (gas sensing functional groups) A, B, and S can be easily introduced into a conjugated polymer, and by combining it with a carbon material (mainly exhibiting electrical conductivity), an electron transfer channel can be established, and sufficient contact reaction (sensing) can be realized for a gas component contacted from the outside. In particular, it is possible to realize sensitivity to a specific gas component by changing the current density upon contact with a specific gas component (nitrogen-based substance, for example, ammonia). [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a conceptual diagram showing a gas sensor equipped with a gas sensing material. [Diagram 2] FIG. 2 is a schematic diagram showing the surface structure of the gas sensing material. [Diagram 3] FIG. 3 is a schematic diagram showing a gas-sensing material in which polypyrrole having a specific gas-sensing functional group bound to the surface thereof and carbon nanotubes are combined by capping. [Figure 4] FIG. 4 is a magnified SEM image of nanoparticles of the gas sensing material according to the present invention. [Diagram 5] FIG. 5 is a magnified SEM image of the nanotubes of the gas sensing material according to the present invention. [Figure 6] FIG. 6 shows the resistance change indicating the gas response of the gas sensor according to the present invention. [Figure 7] FIG. 7 shows the resistance change that represents the gas response of a gas sensor that does not use a carbon material. [Figure 8] FIG. 8 is a graph evaluating the ammonia gas sensing performance. [Figure 9] FIG. 9 is a graph evaluating the response performance of ammonia gas under humidification. [Figure 10] FIG. 10 is a graph evaluating the response performance of ammonia gas under humidification. [Figure 11] FIG. 11 is a graph evaluating the response performance of ammonia gas measured at relative humidity of 50% and 70%. [Figure 12] FIG. 12 is a graph evaluating the response performance of ammonia gas under humidified conditions in the examples and comparative examples. [Figure 13] FIG. 13 illustrates the resistance change representing the response of the gas sensor of the present invention to acetone gas. [Figure 14] FIG. 14 illustrates the resistance change representing the response of the gas sensor of the present invention to acetone gas. [Figure 15]FIG. 15 illustrates the resistance change representing the response of the gas sensor of the present invention to ammonia gas. [Figure 16] FIG. 16 illustrates the resistance change representing the response of the gas sensor of the present invention to ammonia gas. [Figure 17] FIG. 17 illustrates the resistance change representative of the formaldehyde gas response of the gas sensor according to the present invention. [Figure 18] FIG. 18 illustrates the resistance change representative of the formaldehyde gas response of the gas sensing sensor according to the present invention. [Figure 19] FIG. 19 illustrates the resistance change representative of the methyl mercaptan gas response of a gas sensing sensor according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [Gas sensing material] The gas sensing material is a concept that encompasses all categories of materials that sense, detect, detect, confirm, etc. gas, without being bound by the word "sensing" in the name, such as gas sensing materials, gas detection materials, gas detection materials, gas confirmation materials, etc.

[0016] One aspect of the present invention is a gas sensing material comprising polypyrrole represented by the following chemical formula I and a carbon material. The gas sensing material of the present invention has high sensitivity, high selectivity, a wide range of usable mobility, thin film thickness, and flexibility, and when used in a sensing device, it is possible to achieve miniaturization and low power consumption.

[0017] In one aspect of the present invention, there is provided a gas sensing material comprising: The film comprises at least a first layer and a second layer, Either the first layer or the second layer comprises a compound represented by the following chemical formula I: It can be proposed that either the first layer or the second layer, or the other of them, comprises a carbon material.

[0018] A compound represented by the chemical formula I In the present invention, a polypyrrole derivative represented by the following chemical formula I is used, that is, a polypyrrole derivative having functional groups (gas sensing functional groups) A, B, and S. This compound imparts high sensitivity, high selectivity, and a wide range of usability as a gas sensing material.

[0019] [ka]

[0020] In the above formula I, A is an alkyl group having 1 to 10 carbon atoms or a phenyl group, B is a hydrogen atom, a halogen atom or a halogen compound; S is a sulfur atom, a nitrogen atom, an oxygen atom, or a polar compound composed of these atoms, A, B, and S are different substances; n is greater than or equal to 100 and less than or equal to 100,000.

[0021] In the A, examples of the alkyl group having 1 to 10 carbon atoms include CH3-, CH3CH2-, and combinations thereof. Examples of the phenyl group include C6H5-, C6H5CH2-, and combinations thereof.

[0022] In B, the halogen atom may be one or a combination of two or more selected from the group consisting of a fluorine atom (F), a chlorine atom (Cl), a bromine atom (Br), an iodine atom (I), and an astatine atom (At), which belong to Group 17 of the periodic table, and preferably one or a combination of two or more selected from the group consisting of a fluorine atom (F), a chlorine atom (Cl), and a bromine atom (Br).

[0023] In the above B, the halogen compound may be, for example, one or a combination of two or more selected from the group consisting of H-, Cl-, and F-. Preferably, in order to differentiate the function from that of A, B is composed of different compounds having optical isomer structures, and provides an arrangement or directionality of the molecular structure.

[0024] In the above S, examples of polar compounds composed of a sulfur atom, a nitrogen atom, or an oxygen atom include -O-, -OCH2-, -CO-, -COO-, CO-NH-, -CH=CH-COO-, -OCO-CH2-, -C=O, -NH3, -OH 2+ , -OH, and -COOH. The selectivity of gas components is characterized by being differentiated based on the molecular structure of the S consisting of these groups. For example, -NH3 is selectively sensitive to ammonia gas components, and -C=O, -CH=CH-COO-, or -COOH can have high sensitivity to gas components such as acetone or aldehyde (preferably formaldehyde). Of course, these descriptions are merely illustrative, and the present invention is not to be construed as being limited to the selectivity or functionality of the S for a specific gas.

[0025] In particular, the structure of the functional groups S and A in the surface structure of the nano-substance determines the selectivity of the gas to be detected, as shown in Figure 3. The basic structure of the functional groups S and A can include a carboxyl group, an alcohol group, a ketone group, an amine group, a phenyl, and a C1-C6 compound. It is preferable that the functional groups S and A are composed of different substances having structural characteristics as optical isomers.

[0026] n is 100 or more and 100,000 or less, and preferably 1,000 or more and 10,000 or less.

[0027] (Carbon materials) Carbon materials are made up of carbon atoms, and mainly allotropes of carbon are used. Carbon materials, as gas sensor materials, impart high electrical conductivity and realize high sensitivity.

[0028] The carbon material may be, for example, natural or synthetic (cubic) diamond. D , lonsdaleite (natural or synthetic hexagonal diamond), graphite (plate-shaped graphene laminates; for example, graphite, graphite), amorphous carbon (carbon powder such as charcoal, activated carbon, carbon black, or acetylene black), glassy carbon, graphene, fullerene (spherical graphene structure), carbon nanotube (cylindrical graphene structure), carbon nanohorn (cylindrical graphene structure), carbon nanobud, carbon nanofiber, carbon nanofoam, and carbyne.

[0029] In the present invention, the carbon material may be one or a combination of two or more selected from the group consisting of graphite, amorphous carbon, glassy carbon, graphene, fullerene, carbon nanotube, carbon nanohorn, carbon nanobud, carbon nanofiber, and carbon nanofoam. Preferably, the carbon material may be one or a combination of two or more selected from the group consisting of graphite, amorphous carbon, graphene, fullerene, carbon nanotube (preferably single-walled carbon nanotube), carbon nanohorn, carbon nanobud, carbon nanofiber, and carbon nanofoam. More preferably, the carbon material may be one or a combination of two or more selected from the group consisting of graphene, fullerene, carbon nanotube (preferably single-walled carbon nanotube), carbon nanohorn, carbon nanobud, carbon nanofiber, and carbon nanofoam.

[0030] (chemical bond) According to one aspect of the present invention, it is preferable that the compound represented by the above-mentioned [Chemical Formula I] and the above-mentioned carbon material are bonded (by a chemical bond, a physical bond, or a mixed bond thereof, preferably a chemical bond) directly or via a bonding group.

[0031] The bonding group is a divalent bonding group, and is selected from the group consisting of -(C2)m (m is 1 or more and 10 or less), -O-, -S-, -OCH2-, -CHO-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NH-, -NH-CO-, -SCH2-, -CH2S-, -CF2O-, -OCF2-, -CF2S-, -SCF2-, -CH=CH-COO-, -CH=CH-OCO-, -COO- and a combination of two or more selected from the group consisting of CH=CH-, -OCO-CH=CH-, -COO-CHCH-, -OCO-CHCH-, -CHCH-COO-, -CHCH-OCO-, -COO-CH-, -OCO-CH-, -CH-COO-, -CH-OCO-, -CH=CH-, -N=N-, -CH=NN=CH-, -CF=CF-, and -C≡C-.

[0032] (sensing conditions) The gas sensing material according to the present invention is subjected to an atmospheric pressure of 1 to 5 atmospheres, preferably 1 atmosphere or normal pressure. The relative humidity is preferably 10% to 100%, and more preferably 20% to 60%. The temperature is preferably -50°C to 100°C, and more preferably 10°C to 40°C. Gas is sensed and detected under a combination of these sensing conditions. In particular, in the present invention, the gas sensing material is used to detect gases emitted by respiratory exhalation in a living body.

[0033] (Gas: X group) The gas to be sensed may be a nitrogen-based compound, an alcohol, a ketone, or an aldehyde, and is preferably ammonia, urea, acetone, formaldehyde, acetaldehyde, or an alcohol having 1 to 5 carbon atoms.

[0034] (Other gases: Y group) In the present invention, the gas to be sensed is a thiol compound (mercaptan compound), specifically, an alkyl mercaptan having 1 to 5 carbon atoms, preferably methyl mercaptan or ethyl mercaptan.

[0035] The gas sensing material of the present invention can detect gases at a level of 1 PPM or less under the above-mentioned wide range of sensing conditions, achieving excellent high sensitivity, and can sense gases at temperatures between -50°C and 100°C, particularly at room temperature, and achieves high sensitivity at relative humidity between 10% and 100%, and can achieve thin films of the order of 500 nm or less and low resistance.

[0036] (Production example) According to the first aspect of the present invention, the gas sensing material is obtained by mixing the compound represented by the [chemical formula I] with a carbon material. According to the second aspect of the present invention, the gas sensing material is obtained by forming a first layer or a second layer containing the compound represented by the [chemical formula I] and a first layer or a second layer containing a carbon material, respectively, and then forming a second layer. According to the third aspect of the present invention, the gas sensing material is obtained as a complex by preparing the compound represented by the [chemical formula I] and a carbon material, and chemically bonding the compound represented by the [chemical formula I] with the carbon material directly or via a bonding group. The details of the manufacturing method will be described later.

[0037] [Gas sensing material type: X group] According to one aspect of the present invention, a gas sensing material is proposed which is composed of a polypyrrole derivative (represented by [Chemical Formula I]) represented by the following [Chemical Formula II] and carbon nanotubes. [ka]

[0038] In the above formula II, A, B, S, and n are as defined in Formula I.

[0039] The gas sensing material represented by the formula II is formed by bonding the polypyrrole derivative represented by the formula I to a carbon nanotube (preferably a single-walled carbon nanotube) via a carbonyl group.

[0040] [Ammonia gas sensing material] According to one aspect of the present invention, there is provided an (ammonia) gas sensing material, The gas is ammonia, In the above formula I and formula II, A is a phenyl group; B is a hydrogen atom, a halogen atom or a halogen compound; S is a nitrogen atom or a nitrogen-containing functional group; A, B, and S are different substances; A gas sensing material is proposed, where n is 100 to 100,000.

[0041] In the above B, the halogen atom or halogen compound and the above n are the same as defined in the above Chemical Formula I. In the above S, the nitrogen atom-containing functional group can be one or a combination of two or more selected from the group consisting of an amino group, an imino group, a nitro group, a nitroso group, an azo group, a hydrazo group, a diazo group, and a cyano group, and preferably one or a combination of two or more selected from the group consisting of an amino group, an imino group, a nitro group, a nitroso group, an azo group, a hydrazo group, a diazo group, and a cyano group.

[0042] (sensing conditions) The gas sensing material according to the present invention has an atmospheric pressure of 1 to 5 atmospheres, preferably normal pressure. The relative humidity is 0% or more (preferably 10% or more) and 100% or less, preferably 20% to 60%. The temperature is -30°C to 100°C, preferably 10°C to 40°C. In addition, ammonia gas is sensed and detected in these combinations. Particularly, in the present invention, it is used to sense gases emitted by respiratory exhalation in a living body.

[0043] [Acetone gas sensing material] According to one aspect of the present invention, there is provided an (acetone) gas sensing material, comprising: The gas is acetone, In the above formula I and formula II, A is a methyl group or an oxygen atom; B is a hydrogen atom or a sulfur atom; S is -OH 2+ , -OH or -COOH; A, B, and S are different substances; A gas sensing material is proposed, where n is 100 to 100,000.

[0044] (sensing conditions) The gas sensing material has an atmospheric pressure of 1 to 5 atmospheres, preferably normal pressure. The relative humidity is 0% or more (preferably 10% or more) and 100% or less, preferably 20% to 60%. The temperature is -30°C to 100°C, preferably 10°C to 40°C. In addition, ammonia gas is sensed and detected in these combinations. Particularly, in the present invention, it is used to sense gases emitted by respiratory exhalation in a living body.

[0045] [One embodiment of gas sensing material: Y group] [Gas sensing material] According to one aspect of the present invention, there is provided a gas sensing material, comprising: The present invention has a structure of a polypyrrole derivative and carbon nanotubes represented by the following chemical formula III: A gas sensing material is proposed in which the gas is acetone, ammonia, formaldehyde, or methyl mercaptan. [ka]

[0046] (sensing conditions) The gas sensing material according to the present invention has an atmospheric pressure of 1 to 5 atmospheres, preferably normal pressure, and a temperature of -30°C to 100°C, preferably 10°C to 40°C. In addition, in these combinations, the gas sensing material senses and detects each of acetone, ammonia, formaldehyde, and methyl mercaptan.

[0047] [(Acetone) gas sensing material] According to one aspect of the present invention, there is provided an (acetone) gas sensing material, comprising: The present invention has a structure of a polypyrrole derivative and carbon nanotubes represented by the following [chemical formula IV], A gas sensing material is proposed in which the gas is acetone. [ka]

[0048] (sensing conditions) The gas sensing material according to the present invention has an atmospheric pressure of 1 to 5 atmospheres, preferably normal pressure, and a temperature of -30°C to 100°C, preferably 10°C to 40°C. In addition, in these combinations, acetone is sensed and detected.

[0049] [Gas sensor: gas sensing element] The present invention can propose a gas sensor (gas sensing element) comprising an electrode and the gas sensing material of the present invention. The gas sensor according to the present invention can be constructed by forming the gas sensing material according to the present invention into a transparent thin film and sandwiching it between transparent electrodes, as shown in FIG. The gas sensor according to the present invention is a main component of a gas sensing device, and is particularly used as one of the multi-function sensors for sensing gas, pressure, contact, temperature, etc.

[0050] [Method of manufacturing gas sensing material] In one aspect of the present invention, there is provided a method for producing a gas sensing material according to the present invention, comprising the steps of: (S1) preparing a conjugated polymer monomer, a carbon material, a transition metal salt catalyst, an emulsifier and / or a dispersant, and a functional organic substance; (S2) A dispersion liquid is obtained by mixing a carbon material, a transition metal salt, and an emulsifier and / or a dispersant, (S3) adding the conjugated polymer monomer and the functional organic substance to the dispersion liquid and emulsion-polymerizing the mixture; (S4) A production method is proposed, which comprises purifying and separating the polymerization product to obtain the gas-sensing material.

[0051] (S1) In (S1), a conjugated polymer monomer, a carbon material, a transition metal salt catalyst, an emulsifier and / or a dispersant, and a functional organic substance are prepared.

[0052] <Monomers for conjugated polymers> The monomer of the conjugated polymer is a monomer that constitutes a conjugated polymer synthesized by emulsion polymerization. The monomer of the conjugated polymer may be one or a combination of two or more selected from the group consisting of pyrrole, aniline, thiophene, 3,4-ethylenedioxythiophene, and thiophene, and is preferably pyrrole. The conjugated polymer may be one or a combination of two or more selected from the group consisting of polypyrrole, polyaniline, polythiophene, poly-3,4-ethylenedioxythiophene, and polythiophene, and is preferably polypyrrole.

[0053] Carbon Materials The carbon material may be the same as that described in the section on gas sensing material. In the present invention, preferably, carbon nanotubes, more preferably single-walled carbon nanotubes, are used. The length of the carbon nanotubes is preferably 1 μm or more, more preferably 10 μm or more.

[0054] <Transition metal salt catalyst> A transition metal salt catalyst is a catalyst that promotes the emulsion polymerization of pyrrole monomers. A specific example of a transition metal salt catalyst is iron chloride (FeCl3). , and and Fe(III) tosylate.

[0055] <Functional organic substances: organic compounds with gas-sensing functional groups> The functional organic substance is a substance that introduces a gas sensing functional group into the gas sensing material. The functional organic substance may be one or a combination of two or more selected from the group consisting of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), polyacrylamide (PAA), dodecyl sulfonate, camphorsulfonic acid, and hexadecyltrimethylammonium salt.

[0056] By introducing a functional organic substance into a conjugated polymer as a specific functional group, for example, it becomes possible to realize the functional groups A, B, and S (gas-sensing functional groups) in the above chemical formula I.

[0057] (S2) In (S2), a carbon material, a transition metal salt, and an emulsifier and / or a dispersant are mixed to obtain a dispersion.

[0058] <Dispersion> The dispersion can be obtained by dissolving and / or dispersing each material in water or a polar solvent. Dispersion can be carried out under various conditions, and may be carried out in an air atmosphere at room temperature (about 25° C.).

[0059] (S3) In (S3), the conjugated polymer monomer and the functional organic substance are added to the dispersion liquid and emulsion-polymerized.

[0060] (S3) In (S3), the conjugated polymer monomer and the functional organic substance are emulsion-polymerized to include functional groups (gas-sensing functional groups) A, B and / or S (e.g., carboxyl group, alcohol group, ketone group, amine group, etc.) on the surface of the conjugated polymer, thereby forming nanoparticles or nanorods of the conjugated polymer. On the surface of the conjugated polymer nanoparticles or nanorods, a gas-sensing material having a structure in which a positive charge and the gas-sensing functional group are linked (capped) while maintaining a chemical bond relationship can be produced. The gas-sensing material is produced in the form of particles with a diameter of 30 nm to 100 nm, or in the form of a cylinder or rod with a diameter of 30 nm to 100 nm and a length of 5 nm to 100 μm.

[0061] In (S3), the gas sensing material produced is as shown in Figures 2 and 3. As shown in Figure 2, the selectivity for a specific gas is determined by the structure of the gas sensing functional groups S and A in the surface structure of the nanoparticles. The gas sensing functional groups are, for example, a carboxy group, an alcohol group, a ketone group, an amine group, a phenyl group, and a C 1-6 The gas selectivity is determined by the structure of the gas sensing functional groups S and A on the surface structure of the gas sensing substrate (nano rod) shown in FIG.

[0062] In (S3), the emulsion polymerization reaction is carried out at a low temperature below room temperature, preferably below 0° C. By controlling the polymerization temperature, it is easy to form nano-sized particles or rods and improve the electrical conductivity.

[0063] (S4) In (S4), the polymerization product is purified and separated to obtain the gas sensing material. In (S4), the nano-structured gas sensing material obtained in (S3) is purified and separated, for example, by centrifugation to separate the remaining raw materials, by-products, etc. Also, preferably, the obtained nano-structured gas sensing material may be dispersed in a solvent (e.g., a tetrahydrofuran aqueous solution) and subjected to solid-liquid separation to remove impurities such as unreacted substances, and this process may be repeated two or three times. In fact, the unreacted substances dispersed in the tetrahydrofuran solution are individually separated in the upper layer, and the nano-structured gas sensing material can be separated in the lower layer due to the difference in specific gravity. Also, according to a preferred embodiment, the unreacted polymer can be additionally removed by using a chloroform solvent, and a pure nano-structured gas sensing material can be obtained. The obtained gas sensing material is produced as spherical particles having a diameter of 30 nm to 100 nm, or as rod-shaped structures having a diameter of 30 nm to 100 nm and a length of 5 nm to 100 μm.

[0064] (Optional / additional process) The obtained gas sensing material can be prepared as a dispersion by secondary dispersion in water or an organic solvent such as methanol, butanol, or isopropanol, and then coated onto a substrate to obtain a gas sensing thin film material.

[0065] [Gas sensing material obtained by the manufacturing method of gas sensing material] In one aspect of the present invention, a gas sensing material (gas sensor) obtained by the method for producing a gas sensing material according to the present invention is proposed. (S1) preparing a conjugated polymer monomer, a carbon material, a transition metal salt catalyst, an emulsifier and / or a dispersant, and a functional organic substance; (S2) A dispersion liquid is obtained by mixing a carbon material, a transition metal salt, and an emulsifier and / or a dispersant, (S3) adding the conjugated polymer monomer and the functional organic substance to the dispersion liquid and emulsion-polymerizing the mixture; (S4) A gas sensing material (gas sensor) obtained by purifying and separating the polymerization product. Therefore, the method for producing the gas sensing material (gas sensor) is the same as that explained in the section "Method for producing the gas sensing material." EXAMPLES

[0066] The present invention will be described with reference to the following examples, but the scope of the present invention is not limited to these examples. In addition, various aspects of the present invention disclosed in this specification can be easily implemented by those skilled in the art from these examples.

[0067] [Embodiment: Group X] [Manufacture of gas sensing material] (Gas sensing material 1) In a reactor, 1 wt % of PVP (polyvinylpyrrolidone: molecular weight 1,300,000) was dissolved and dispersed in deionized water as a dispersant, and then 2.7 g of iron chloride (FeCl3) was added. Next, PA (phenylalanine) was added at a molar ratio of 0.3 to the pyrrole monomer to form micelles of 60 μm in size. After adding 2% by weight of pyrrole monomer, the reaction was carried out by emulsion polymerization at 0°C for 5 hours. After the reaction was completed, methanol was added in an amount approximately equal to that of the reaction solution, and the reaction product particles were then collected after separation. The synthesized nanostructured sensing material was subjected to secondary purification and separation by centrifugation to obtain a spherical nanoparticle structure (gas sensing material 1). As shown in FIG. 4, this nanoparticle structure (gas sensing material 1) was a nanoparticle of conductive polymer polypyrrole with phenylalanine functional groups bound to the surface, and had an average diameter of approximately 50 nm to 80 nm.

[0068] (Gas sensing material 2) Gas sensing material 2 was obtained in the same manner as gas sensing material 1, except that 0.003 wt % of single-walled carbon nanotubes (SWCNTs) and hexadecyltrimethylammonium salt (HDTMA) were used as a dispersant, and polymerization was carried out while stirring at approximately 1000 rpm. The gas-sensing material 2 was a rod-shaped body with a size of 200 nm to 10 μm. The gas-sensing material 2 was a conjugated carbon nanomaterial in which the surface of a single-walled carbon nanotube was covered with a conductive polymer polypyrrole having a phenylalanine functional group bonded to the surface. The electron microscope photograph of this is shown in FIG.

[0069] [Manufacture of gas detection sensor] (Gas sensor 1) The carbon material used was the single-walled carbon nanotube (SWCNT) used in the manufacture of the gas sensing material 2. SWCNT and the gas sensing material 1 were formed on a glass substrate with a metal comb-shaped electrode by spin coating at room temperature (25°C). The resistance was adjusted to 10Ω or more and 1MΩ or less by adjusting the rotation speed to 500-7000 rpm, and the gas sensing sensor 1 was obtained.

[0070] (Gas sensor 2) The dispersion liquid of the gas sensing material 2 was formed into a film at room temperature (25° C.) by spin coating in the same manner as in the manufacture of the gas sensor 1. The resistance value was adjusted to 10Ω or more and 1MΩ or less by adjusting the rotation speed to 500 rpm to 7000 rpm, and the gas sensor 2 was obtained.

[0071] (Gas Sensor (Comparative Example 1)) As Comparative Example 1, a gas sensor 1 from which only the carbon material was removed was used.

[0072] Example 1 [Gas sensor evaluation test (ammonia)] (test) Gas sensor 1 was installed in a gas introduction vessel, and the response of ammonia gas was measured at room temperature (25°C). 100 ppb ammonia gas diluted with pure air and pure air were alternately flowed. In both cases, the flow rate was 300 sccm and the relative humidity was 0%. The gas response was monitored by applying a voltage to the sensor using an electrometer to measure the current and the resistance value. The change in resistance is shown in Figure 6. On the other hand, for comparison, a gas sensor (Comparative Example 1) was used in which the carbon material was omitted from the gas sensing material 1, and the response to ammonia gas of the same concentration was evaluated under the same conditions as above. The results are shown in FIG.

[0073] (result) As shown in Figure 6, we were able to confirm that the resistance increases with ammonia and returns to normal with pure air. We also confirmed that the change in resistance (ΔR) observed at this time was sufficiently large. On the other hand, as shown in Fig. 7, it was confirmed that the noise increased and the sensitivity was low compared to the characteristics of the gas sensor of the present invention. Here, the sensitivity is expressed as S (%) = ΔR (resistance change value) / R0 (initial resistance value) × 100, and a decrease in sensitivity was observed because R0 was high.

[0074] Example 2 [Evaluation test of gas sensor (ammonia)] (test) The gas sensor 1 was used to evaluate the ammonia gas sensing performance. The resistance change was confirmed for ammonia concentrations of 100 ppb, 500 ppb, and 1 ppm, and the amount of change was plotted against the concentration as an index called S. The results are shown in Figure 8.

[0075] (result) In Fig. 8, the concentration at which the extrapolated S is higher than the noise level is called the limit of detection (LOD). In the present invention, a detection sensitivity of 20 ppb was obtained.

[0076] Example 3 [Evaluation test of gas sensor (ammonia)] (test) The gas sensor 2 was used to evaluate the detection performance of ammonia gas. The evaluation result at an ammonia concentration of 500 ppb is shown in Figure 9. In addition, the resistance change at ammonia concentrations of 100 ppb, 500 ppb, and 1 ppm was confirmed, and the amount of change was plotted against the concentration as an index called S. The results are shown in Figure 10.

[0077] (result) In Fig. 10, the concentration at which the extrapolated S is higher than the noise level is called the limit of detection (LOD). In the present invention, a detection sensitivity of 20 ppb was obtained. Both the gas sensor 1 and the gas sensor 2 showed high sensitivity with a detection limit of about 20 ppb for ammonia gas. Ammonia gas has three hydrogen atoms and one lone pair at the center of the nitrogen atom. When the gas sensor of Comparative Example 1 is used, ammonia gas reacts with the positive charge of the phenylalanine functional group, and as a result, the conductivity of the polaron structure of the doped polypyrrole is reduced, which is thought to be detected as a change in electrical signal.

[0078] On the other hand, in the gas detection sensor 1 (comprising gas sensing material 1 and a carbon material) and gas detection sensor 2 (comprising gas sensing material 2) of the present invention, the conductive polymer polypyrrole having a phenylalanine functional group that reacts specifically to ammonia gas and the carbon material that exhibits high conductivity form a complex that forms an electrical path, so that it is believed that sensitivity is improved because the weak current change caused by gas adsorption in the functional group-containing conductive polymer polypyrrole can be sensitively read as an electrical signal by the highly conductive, low-noise carbon material.

[0079] Example 4 [Gas sensor evaluation test (ammonia)] (test) Using the gas sensor 1, the response of ammonia gas was measured under humid conditions. The gas sensor 1 was attached inside a container into which gas was introduced, and the response of ammonia gas was measured at room temperature. 500 ppb of ammonia gas diluted with pure air and pure air were alternately flowed. The flow rate for both was 300 sccm. The humidity was measured at relative humidity of 50% and 70%. The results are shown in Figure 11. It was confirmed that the resistance increases with ammonia, and returns to normal with air. In the present invention, even when the humidity was RH 50% and 70%, the sensing sensitivity was equal to or higher than that at RH 0%.

[0080] (result) The results of using the gas sensor 1 and the results of using a gas sensor made only of conductive polypyrrole having phenylalanine functional groups (Comparative Example 1) are shown in Figure 12. In Figure 12, the dashed line indicates the measured value using a gas sensor made only of conductive polypyrrole having phenylalanine functional groups (Comparative Example 1). It was confirmed that the gas sensor according to the present invention has better humidity resistance than conductive polypyrrole alone (Comparative Example 1).

[0081] Example 5 [Evaluation test of gas sensor (acetone)] (test) The acetone gas sensing performance of gas sensor 1 was evaluated. Gas sensor 1 was attached inside a container into which gas was introduced, and the response to acetone gas was measured at room temperature. 100 ppm acetone gas diluted with pure air and pure air were alternately flowed. In both cases, the flow rate was 300 sccm. Humidity was measured at 0% relative humidity. Acetone sensitivity was confirmed to be approximately 100 ppm. It was difficult to confirm a response at acetone gas concentrations lower than this. This result shows that there is selectivity for acetone.

[0082] (result) From the results of the above examples, it can be seen that, when using the product manufactured by the gas sensor manufacturing method according to the present invention, a gas sensor (film) with significantly improved ammonia gas sensing characteristics can be manufactured even at room temperature below 40° C. In addition, according to the present invention, there is no change in sensitivity even at high humidity conditions of 80% or more, which shows a very effective effect required for commercialization.

[0083] [Embodiment: Y group] [Manufacture of gas sensing material] (Gas sensing material 3) In a reactor, 1 wt % of PVP (polyvinylpyrrolidone: molecular weight 1,300,000) was dissolved and dispersed in deionized water as a dispersant, and then 2.7 g of iron chloride (FeCl3) was added. Next, LA (lactic acid) was added at a molar ratio of 0.3 to the pyrrole monomer to form micelles of 60 μm in size. After adding 2% by weight of pyrrole monomer, the reaction was carried out by emulsion polymerization at 0°C for 5 hours. After the reaction was completed, methanol was added in an amount approximately equal to that of the reaction solution, and the reaction product particles were then collected after separation. The synthesized nanostructured sensing material was subjected to secondary purification and separation by centrifugation to obtain a spherical nanoparticle structure (gas sensing material 3).

[0084] (Gas sensing material 4) Gas sensing material 4 (structure represented by [chemical formula III]) was obtained in the same manner as gas sensing material 3, except that 0.003 wt % of single-walled carbon nanotubes (SWCNTs) and hexadecyltrimethylammonium salt (HDTMA) were used as a dispersant and polymerization was carried out while stirring at approximately 1000 rpm. The gas-sensing material 4 was a rod-shaped body having a size of 200 nm to 10 μm. The gas-sensing material 4 was obtained as a conjugated carbon nanomaterial having a structure in which a conductive polymer polypyrrole having a lactic acid functional group bonded to the surface covers the surface of a single-walled carbon nanotube.

[0085] (Gas sensing material 5) In a reactor, 1 wt % of PVP (polyvinylpyrrolidone: molecular weight 1,300,000) was dissolved and dispersed in deionized water as a dispersant, and then 2.7 g of iron chloride (FeCl3) was added. Next, 0.3 molar ratio of PLA (phenyllactic acid) to pyrrole monomer was added to form micelles with a size of 60 μm. After adding 2% by weight of pyrrole monomer, the reaction was carried out by emulsion polymerization at 0°C for 5 hours. After the reaction was completed, methanol was added in an amount approximately equal to that of the reaction solution, and the reaction product particles were collected after separation. The synthesized nanostructured sensing material was subjected to secondary purification and separation by centrifugation to obtain a spherical nanoparticle structure (gas sensing material 5).

[0086] (Gas sensing material 6) Gas sensing material 6 (structure represented by [chemical formula IV]) was obtained in the same manner as gas sensing material 5, except that 0.003 wt % of single-walled carbon nanotubes (SWCNTs) and hexadecyltrimethylammonium salt (HDTMA) were used as a dispersant and polymerization was carried out while stirring at approximately 1000 rpm. The gas sensing material 6 was a rod-shaped body having a size of 200 nm to 10 μm. The gas sensing material 4 was obtained as a conjugated carbon nanomaterial having a structure in which a conductive polymer polypyrrole having a phenyllactic acid functional group bonded to the surface covers the surface of a single-walled carbon nanotube.

[0087] [Manufacture of gas detection sensor] (Gas sensor 3) The dispersion of the gas sensing material 4 was drop-cast onto a comb-shaped electrode substrate having a metal comb-shaped electrode formed on a glass substrate, and a film was formed at room temperature (25° C.). The resistance value was adjusted to 10Ω or more and 100MΩ or less by adjusting the number of drop-casts, and the gas sensing sensor 3 was obtained.

[0088] (Gas Sensor 4) The dispersion of the gas sensing material 6 was drop-cast onto a comb-shaped electrode substrate having a metal comb-shaped electrode formed on a glass substrate, and a film was formed at room temperature (25° C.). The resistance value was adjusted to 10Ω or more and 100MΩ or less by adjusting the number of drop-casts, and the gas sensing sensor 4 was obtained.

[0089] Example 6 [Evaluation test of gas sensor (acetone)] (test) The gas sensor 3 was installed in a gas introduction vessel, and the response of acetone gas was measured at room temperature (25°C). Pure air and 50 ppb of acetone gas diluted with pure air were alternately flowed. In both cases, the flow rate was 600 sccm, and the relative humidity was 0%. The gas response was monitored by applying a voltage to the sensor using an electrometer to measure the current and monitor the resistance value. The change in resistance was as shown in Figure 13.

[0090] (result) As shown in Figure 13, we were able to confirm that the resistance decreased with acetone and returned to normal with pure air. This signal was reproducible over several cycles, with a signal-to-noise (S / N) ratio of 5 or higher.

[0091] Example 7 [Gas Sensor Evaluation Test (Acetone)] (test) The gas sensor 4 was installed in a gas introduction vessel, and the response of acetone gas was measured at room temperature (25°C). Pure air and 50 ppb of acetone gas diluted with pure air were alternately flowed. In both cases, the flow rate was 600 sccm and the relative humidity was 0%. The gas response was monitored by applying a voltage to the sensor using an electrometer to measure the current and monitor the resistance value. The change in resistance was as shown in Figure 14.

[0092] (result) As shown in Figure 14, we were able to confirm that the resistance decreased with acetone and returned to normal with pure air. This signal was reproducible over several cycles, with a signal-to-noise (S / N) ratio of 10 or more.

[0093] Example 8 [Evaluation test of gas sensor (ammonia)] (test) The gas sensor 3 was installed in a gas introduction vessel, and the response of ammonia gas was measured at room temperature (25°C). 1 ppm ammonia gas diluted with pure air and pure air were alternately flowed. In both cases, the flow rate was 300 sccm and the relative humidity was 0%. The gas response was monitored by applying a voltage to the sensor using an electrometer to measure the current and monitor the resistance value. The change in resistance was as shown in Figure 15. Similarly, 100 ppb ammonia gas diluted with pure air and pure air were alternately flowed. The flow rate for both was 300 sccm and the relative humidity was 0%. The gas response was monitored by applying a voltage to the sensor using an electrometer to measure the current and the resistance value. The resistance change was as shown in Figure 16.

[0094] (result) As shown in Figures 15 and 16, we were able to confirm that the resistance increased with ammonia and returned to normal with pure air. This signal was reproducible over several cycles, with the signal-to-noise (S / N) ratio at 1 ppm ammonia being over 60 and the signal-to-noise (S / N) ratio at 100 ppb ammonia being over 10.

[0095] Example 9 [Evaluation test of gas sensor (formaldehyde)] (test) The gas sensor 3 was installed in a gas introduction vessel, and the response of formaldehyde gas was measured at room temperature (25°C). 100 ppb of formaldehyde diluted with pure air and pure air were alternately flowed. In both cases, the flow rate was 300 sccm and the relative humidity was 0%. The gas response was monitored by applying a voltage to the sensor using an electrometer to measure the current and the resistance value. The change in resistance is shown in Figure 17. Similarly, 50 ppb formaldehyde diluted with pure air and pure air were alternately flowed. The flow rate for both was 300 sccm and the relative humidity was 0%. The gas response was monitored by applying a voltage to the sensor using an electrometer to measure the current and the resistance value. The change in resistance is shown in Figure 18.

[0096] (result) As shown in Figures 17 and 18, we were able to confirm the phenomenon in which the resistance was reduced by formaldehyde and restored by pure air. This signal was reproducible over several cycles, and we were able to confirm high performance, with the sensitivity S (%) = ΔR (resistance change) / R0 (initial resistance) × 100 being 0.2 or more for a concentration of 50 ppb, and the signal-to-noise (S / N) ratio being 10 or more.

[0097] Example 10 [Gas sensor evaluation test (methyl mercaptan)] (test) The gas sensor 3 was installed in a gas introduction vessel, and the response of methyl mercaptan gas was measured at room temperature (25°C). Pure air diluted with 200 ppb of methyl mercaptan was alternately flowed, and pure air was flowed. In both cases, the flow rate was 300 sccm, and the relative humidity was 0%. The gas response was monitored by applying a voltage to the sensor using an electrometer to measure the current and monitor the resistance value. The change in resistance was as shown in Figure 19.

[0098] (result) As shown in Figure 19, we were able to confirm the phenomenon that the resistance decreased with methyl mercaptan and returned to normal with pure air. This signal was reproducible over several cycles, and we were able to confirm high performance, with the sensitivity S (%) = ΔR (resistance change) / R0 (initial resistance) × 100 being 0.3 or more for a concentration of 200 ppb, and the signal-to-noise (S / N) ratio being 20 or more. [Industrial Applicability]

[0099] The gas sensing material according to the present invention can realize high sensitivity, high selectivity, wide range of use mobility, miniaturization, and low power consumption. According to the manufacturing method according to the present invention, a gas sensing material that is simple, miniaturized, and inexpensive can be obtained. As a result, the gas sensing material according to the present invention can be used for a wide variety of purposes.

Claims

1. A gas sensing material, comprising: The present invention comprises a polypyrrole derivative represented by the following chemical formula I and a carbon material, The gas sensing material, wherein the gas is ammonia. 【Chemistry 1】 [Chemical formula I] [In the above chemical formula I, A is a phenyl group; B is a hydrogen atom, a halogen atom or a halogen compound; S is a nitrogen atom or a nitrogen-containing functional group; A, B, and S are different substances; n is 100 or more and 100,000 or less.

2. A gas sensing material, comprising: The coating composition comprises at least a first layer and a second layer, Either the first layer or the second layer comprises a polypyrrole derivative represented by the following [chemical formula I], the other of the first layer or the second layer comprises a carbon material; A gas sensing material, wherein the gas is acetone. 【Chemistry 2】 [Chemical formula I] [In the above chemical formula I, A is an alkyl group having 1 to 10 carbon atoms or a phenyl group, B is a hydrogen atom, S is a nitrogen atom, an oxygen atom, or a polar compound composed of these atoms; A, B, and S are different substances; n is 100 or more and 100,000 or less.

3. 3. The gas sensing material according to claim 1 or 2, wherein the carbon material is one or a combination of two or more selected from the group consisting of natural or synthetic (cubic) diamond, lonsdaleite, graphite, amorphous carbon, glassy carbon, graphene, fullerene, carbon nanotube, carbon nanohorn, carbon nanobud, carbon nanofiber, carbon nanofoam, and carbyne.

4. 3. The gas sensing material according to claim 1, wherein the compound represented by the formula I is bonded to the carbon material directly or via a bonding group.

5. The linking group is a divalent linking group, -(C ２ ) m (m is 1 or more and 10 or less) -, -O-, -S-, -OCH ２ --, --CH ２ O-, -CO-, -COO-, -OCO-, -CO-S-, -S-CO-, -O-CO-O-, -CO-NH-, -NH-CO-, -SCH ２ --, --CH ２ S-, -CF ２ O-, -OCF ２ -, -CF ２ S-, -SCF ２ -, -CH=CH-COO-, -CH=CH-OCO-, -COO-CH=CH-, -OCO-CH=CH-, -COO-CH ２ CH ２ --, --OCO-CH ２ CH ２ --, --CH ２ CH ２ -COO-, -CH ２ CH ２ -OCO-, -COO-CH ２ -, -OCO-CH2-, -CH ２ -COO-, -CH ２ The gas sensing material according to claim 4, which is one or a combination of two or more selected from the group consisting of -OCO-, -CH=CH-, -N=N-, -CH=N-N=CH-, -CF=CF-, and -C≡C-.

6. A gas sensing material, comprising: A gas sensing material having a structure of a polypyrrole derivative and carbon nanotubes, represented by the following chemical formula II. 【Chemistry 3】 [Chemical formula II] [In the above chemical formula II, A is an alkyl group having 1 to 10 carbon atoms or a phenyl group, B is a hydrogen atom, a halogen atom or a halogen compound; S is a sulfur atom, a nitrogen atom, an oxygen atom, or a polar compound composed of these atoms; A, B, and S are different substances; n is 100 or more and 100,000 or less.

7. A gas sensing material, comprising: The present invention comprises a polypyrrole derivative represented by the following chemical formula I and a carbon material, A gas sensing material, wherein the gas is a thiol compound. 【Chemistry 4】 [Chemical formula I] [In the above chemical formula I, A is an alkyl group having 1 to 10 carbon atoms or a phenyl group, B is a hydrogen atom, a halogen atom or a halogen compound; S is a sulfur atom, a nitrogen atom, an oxygen atom, or a polar compound composed of these atoms; A, B, and S are different substances; n is 100 or more and 100,000 or less.

8. A gas sensing material, comprising: The coating composition comprises at least a first layer and a second layer, Either the first layer or the second layer comprises a polypyrrole derivative represented by the following [chemical formula I], the other of the first layer or the second layer comprises a carbon material; A gas sensing material, wherein the gas is a thiol compound. 【Chemistry 5】 [Chemical formula I] [In the above chemical formula I, A is an alkyl group having 1 to 10 carbon atoms or a phenyl group, B is a hydrogen atom, a halogen atom or a halogen compound; S is a sulfur atom, a nitrogen atom, an oxygen atom, or a polar compound composed of these atoms; A, B, and S are different substances; n is 100 or more and 100,000 or less.

9. The gas sensing material according to any one of claims 1 to 8, which senses at 1 atmospheric pressure and at a relative humidity of 10% to 100%.

10. The gas sensing material according to any one of claims 1 to 9, which senses at 1 atmospheric pressure and at a temperature of -50°C or higher and 100°C or lower.

11. 1. A gas sensor comprising: The device comprises a positive electrode, a negative electrode, and a gas sensing material, A gas sensor, wherein the gas sensing material is as defined in any one of claims 1 to 10.

12. A method for producing a gas sensing material, comprising the steps of: (S1) preparing a conjugated polymer monomer, a carbon material, a transition metal salt catalyst, an emulsifier and / or a dispersant, and a functional organic substance; (S2) A carbon material, a transition metal salt, and an emulsifier and / or a dispersant are mixed to obtain a dispersion, (S3) adding the conjugated polymer monomer and the functional organic substance to the dispersion liquid and emulsion-polymerizing the mixture; (S4) purifying and separating the polymerization product to obtain the gas sensing material.

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