WO2021192870A1

WO2021192870A1 - Gas adsorbent and gas sensor

Info

Publication number: WO2021192870A1
Application number: PCT/JP2021/008247
Authority: WO
Inventors: 沖　明男; 松澤　伸行; 達人安藤
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2020-03-25
Filing date: 2021-03-03
Publication date: 2021-09-30

Abstract

The present invention addresses the problem of easily enhancing the detection accuracy of a volatile organic compound, which is a substance to be detected. According to the present invention, a gas adsorbent (1) is electrically connected to an electrode (2) of a gas sensor (100). The gas sensor (100) detects a gas that contains at least a volatile organic compound, which is a substance to be detected. The gas adsorbent (1) comprises conductive particles (11) and a polymer (12). The polymer (12) contains molecules that have an oxygen gas permeability coefficient of 0.15 (cm³·cm/m²·day·atom) or less.

Description

Gas adsorbent and gas sensor

This disclosure generally relates to gas adsorbents and gas sensors. More specifically, the present disclosure relates to a gas adsorbent that adsorbs a gas containing at least a volatile organic compound to be detected, and a gas sensor including the gas adsorbent.

Patent Document 1 describes an electrically insulating base material containing a pair of conductive wires arranged in a circular shape in parallel, a chemically sensitive polymer (gas adsorbent) in contact with the pair of conductive wires, and the chemically sensitive polymer. A chemistry register (gas sensor) containing carbon particles dispersed therein is disclosed. In this chemi-register, when a chemically sensitive polymer adsorbs a volatile organic compound or the like in a gas, the electric resistance value changes. When this chemi-register is used, volatile organic compounds and the like in the gas can be detected based on the change in the electric resistance value of the chemi-register.

Japanese Unexamined Patent Publication No. 2004-340945

An object of the present disclosure is to provide a gas adsorbent and a gas sensor whose detection accuracy of a volatile organic compound to be detected can be easily improved.

The gas adsorbent according to one aspect of the present disclosure is electrically connected to an electrode in the gas sensor. The gas sensor detects a gas containing at least a volatile organic compound to be detected. The gas adsorbent contains conductive particles and a polymer. The polymer contains molecules having an oxygen gas permeability coefficient of 0.15 [cm ³ · cm / m ² · day · atm] or less.

The gas sensor according to one aspect of the present disclosure includes the gas adsorbent and the electrode electrically connected to the gas adsorbent.

FIG. 1 is a cross-sectional view showing an outline of a gas sensor including a gas adsorbent according to an embodiment of the present disclosure. FIG. 2 is a plan view showing an outline of the gas sensor of the above. FIG. 3 is a plan view showing an outline when the gas adsorbent is removed from the gas sensor of the above. FIG. 4 is an explanatory diagram of the operating principle of the gas sensor as described above, and is a schematic view showing a state before the volatile organic compound is adsorbed on the gas adsorbent. FIG. 5 is an explanatory diagram of the operating principle of the gas sensor as described above, and is a schematic view showing a state after the volatile organic compound is adsorbed on the gas adsorbent. FIG. 6 is a correlation diagram between the rate of change in electrical resistance and the gas permeability coefficient of oxygen in the same gas sensor. FIG. 7 is a plan view showing an outline of a gas sensor according to a modified example of the embodiment of the present disclosure. FIG. 8 is a plan view showing an outline when the gas adsorbent is removed from the gas sensor of the above.

(1) Outline Hereinafter, the gas adsorbent 1 (see FIG. 1) and the gas sensor 100 provided with the gas adsorbent 1 (see FIG. 1) of the present embodiment will be described with reference to the drawings. However, the following embodiments are only part of the various embodiments of the present disclosure. The following embodiments can be variously modified according to the design and the like as long as the object of the present disclosure can be achieved. Further, each figure described in the following embodiment is a schematic view, and the ratio of the size and the thickness of each component in the figure does not necessarily reflect the actual dimensional ratio. ..

The gas sensor 100 of the present embodiment contains at least a gas containing the volatile organic compound A1 to be detected when exposed to an atmosphere containing the volatile organic compound A1 to be detected (see FIG. 4). It is configured to detect. The gas sensor 100 of the present embodiment includes a gas adsorbent 1 and an electrode 2 (see FIG. 1) that is electrically connected to the gas adsorbent 1. In this embodiment, the gas sensor 100 includes a pair of electrodes 2 (see FIG. 3).

In the present embodiment, the gas adsorbent 1 is electrically connected to the electrode 2 by having a part of the gas adsorbent 1 directly in contact with the part of the electrode 2. Of course, the gas adsorbent 1 can be electrically connected to the electrode 2 as long as the intermediate member has conductivity even when the intermediate member is arranged between the gas adsorbent 1 and the electrode 2. ..

In the gas sensor 100, when the volatile organic compound A1 contained in the gas is adsorbed on the gas adsorbent 1, the electric resistance of the gas adsorbent 1 changes. This phenomenon will be inferred with reference to FIGS. 4 and 5 below. As shown in FIG. 4, in a state where the volatile organic compound A1 is not adsorbed on the gas adsorbent 1, the conductive particles 11 contained in the gas adsorbent 1 are compared in the distance between the adjacent conductive particles 11. It is getting shorter. When the volatile organic compound A1 is adsorbed on the gas adsorbent 1 in this state, the gas adsorbent 1 expands according to the adsorbed volatile organic compound A1 as shown in FIG. The distance becomes longer. As a result, an insulator such as a polymer 12 is likely to be interposed between the conductive particles 11, and it is presumed that the electrical resistance of the gas adsorbent 1 changes. In FIG. 5, the alternate long and short dash line representing the surface of the gas adsorbent 1 represents the state before the gas adsorbent 1 expands, and the solid line representing the surface of the gas adsorbent 1 represents the gas adsorbent 1. Represents the state after expansion. Further, in FIG. 5, the curve drawn in the polymer 12 represents the polymer chain.

Therefore, the gas sensor 100 can detect the volatile organic compound A1 to be detected by utilizing the change in the electric resistance of the gas adsorbent 1. For example, the gas sensor 100 can measure the change in the electrical resistance of the gas adsorbent 1 by measuring the change in the current while applying a voltage between the pair of electrodes 2, and as a result, the gas adsorbent 1 can be used. It is possible to detect the adsorbed volatile organic compound A1 to be detected.

As shown in FIG. 1, the gas adsorbent 1 contains the conductive particles 11 and the polymer 12. The "polymer" referred to in the present disclosure is a molecule having a large relative molecular weight, and has a structure composed of a large number of repetitions of a unit obtained substantially or conceptually from a molecule having a small relative molecular weight. In other words, it is a polymer molecule. The polymer 12 contains a molecule (hereinafter, also referred to as “specific molecule”) having a gas permeability coefficient of oxygen B1 of 0.15 [cm ³ · cm / m ^{2 · day · atm] or less.} The gas permeability coefficient has a temperature dependence. The gas permeability coefficient of oxygen B1 described below represents a value when the atmospheric temperature is 25 degrees. The polymer 12 may be composed of only specific molecules, or may be composed of a mixture of specific molecules and other molecules.

As described above, in the present embodiment, since the polymer 12 does not easily permeate the oxygen B1 as described above, the gas adsorbent 1 adsorbs the volatile organic compound A1 while making it difficult to adsorb the oxygen B1. ing. Therefore, the present embodiment has an advantage that the detection accuracy of the volatile organic compound A1 to be detected is likely to be improved as compared with the gas adsorbent 1 which does not contain a specific molecule.

(2) Details Hereinafter, the gas adsorbent 1 and the gas sensor 100 of the present embodiment will be described in detail with reference to FIGS. 1 to 3. In the following, one gas sensor 100 in a sensor array composed of a plurality of types of gas sensors 100 will be described. The following description may be similarly applied to other gas sensors 100 in the sensor array.

As shown in FIG. 1, the gas sensor 100 includes a gas adsorbent 1, a pair of electrodes 2, and a base material 3. An electrode 2 is formed on the base material 3. The gas adsorbent 1 is arranged on the base material 3. That is, the gas adsorbent 1 is arranged on the surface of the base material 3. The "surface of the base material" referred to in the present disclosure refers to one side of the base material 3 in the thickness direction that is exposed to the gas containing the volatile organic compound A1 to be detected.

Here, in addition to the case where one gas sensor 100 is arranged on one base material, there are cases where a plurality of types of gas sensors 100 are arranged. In the latter case, the plurality of types of gas sensors 100 form one sensor array. In the following, unless otherwise specified, the location where one gas sensor 100 is arranged on one base material is referred to as “base material 3”. That is, when a plurality of types of gas sensors 100 are arranged on one base material, the one base material includes a plurality of "base materials 3" corresponding to the plurality of types of gas sensors 100.

In the following, one of the pair of electrodes 2 will also be referred to as a "first electrode 21" and the other electrode 2 as a "second electrode 22". Note that FIG. 1 is a cross-sectional view taken along the line X1-X1 of FIG. In FIG. 1, one electrode 2 of the pair of electrodes 2 is represented by a first main piece 211 (described later) included in the first electrode 21, and the other electrode 2 is included in the second electrode 22. It is represented by a second main piece 221 (described later).

The gas adsorbent 1 is in the form of a film (film shape), and when the gas adsorbent 1 (gas sensor 100) is exposed to the gas, it adsorbs the volatile organic compound A1 to be detected contained in the gas. It is configured in. The volatile organic compound A1 may include, for example, ketones, amines, alcohols, aromatic hydrocarbons, aldehydes (eg nonanal), esters, organic acids, methyl mercaptans, or disulfides.

The gas adsorbent 1 contains conductive particles 11 and a polymer 12 having gas adsorbability. In this embodiment, the conductive particles 11 are dispersed in the polymer 12. That is, in the present embodiment, the aggregates of the conductive particles 11 are not concentrated in a part of the polymer 12, but are dispersed throughout the polymer 12.

The term "gas adsorptive" as used in the present disclosure refers to the property of adsorbing the volatile organic compound A1 to be detected contained in the gas when exposed to the gas. It can be determined based on common general technical knowledge that the polymer 12 has gas adsorptivity. For example, when the gas-derived volatile organic compound A1 is detected by exposing the polymer 12 to a gas and then analyzing the polymer 12 with a gas chromatograph mass spectrometer, the polymer 12 has gas adsorptivity. Can be judged to be.

The conductive particles 11 include, for example, at least one or more materials selected from carbon materials, metals, semiconductors, surface-modified nanoparticles and the like. The carbon material may include, for example, carbon black, carbon nanotubes, carbon nanohorns, graphene, graphene nanoribbons, fullerenes, graphite and the like. The metal may include, for example, gold, platinum, iridium, rhodium, palladium, silver, copper, bismuth, antimony, aluminum, titanium, stainless steel, nickel alloys and the like. The semiconductor may include, for example, silicon, germanium, gallium arsenide, gallium phosphide, indium phosphide, gallium nitride, silicon carbide (silicon carbide) and the like. Further, the semiconductor may also include an oxide semiconductor such as IGZO, zinc oxide, or tin oxide, or an organic semiconductor such as pentacene, anthracene, or polythiophene. Materials used for surface modification of nanoparticles can include polyethylene glycol, polymethylmethacrylate, polyethylene oxide, polyvinylpyrrolidone, oligonucleotides, antibodies, peptides and the like.

The conductive particles 11 preferably contain a carbon material, particularly carbon black. This is because carbon black is inexpensive as compared with other materials and has excellent properties for detecting the volatile organic compound A1.

The polymer 12 is selected according to the type of the volatile organic compound A1 to be adsorbed by the gas adsorbent 1 and / or the type of the conductive particles 11 contained in the gas adsorbent 1. The polymer 12 is, for example, an organic polymer and may contain at least one or more molecules selected from, for example, polyvinyl alcohol, polyacrylonitrile, polyvinylidene chloride, polyvinyl fluoride and the like. These molecules (specific molecules) have a gas permeability coefficient of oxygen B1 of 0.15 [cm ³ · cm / m ² · day · atm] or less. In particular, in the present embodiment, the polymer 12 preferably contains, as a specific molecule, a molecule having a gas permeability coefficient of oxygen B1 of 0.1 [cm ³ · cm / m ² · day · atm] or less. As an example, the polymer 12 satisfying this condition may contain at least one or more molecules selected from polyvinyl alcohol, polyacrylonitrile, polyvinylidene chloride and the like.

The pair of electrodes 2 (first electrode 21 and second electrode 22) are all made of, for example, gold or platinum. Both the first electrode 21 and the second electrode 22 are arranged in the base material 3 in a form of being embedded in the base material 3. In the present embodiment, the first electrode 21 has a first main piece 211 and a first terminal 212, as shown in FIG. As shown in FIG. 3, the second electrode 22 has a second main piece 221 and a second terminal 222.

The first main piece 211 and the second main piece 221 are both annular in a plan view. The diameter dimension of the second main piece 221 is larger than the diameter dimension of the first main piece 211. In a plan view, the first main piece 211 is arranged inside the second main piece 221.

The first terminal 212 has a rectangular shape having a length in the left-right direction in a plan view, and is directed from one end (right end in FIG. 3) of the first main piece 211 toward the outside of the base material 3 (right side in FIG. 3). It is protruding. One end of the first terminal 212 is electrically connected to the first pad 31 provided on the surface of the base material 3. The second terminal 222 has a rectangular shape having a length in the left-right direction in a plan view, and is from one end (right end in FIG. 3) of the second main piece 221 toward the outside of the base material 3 (right side in FIG. 3). It is protruding. One end of the second terminal 222 is electrically connected to the second pad 32 provided on the surface of the base material 3. Therefore, by applying a voltage or passing a current to the first pad 31 and the second pad 32, a current flows through the conductive path including the first electrode 21, the second electrode 22, and the gas adsorbent 1.

In the present embodiment, the first electrode 21 and the second electrode 22 (that is, the electrode 2) are gass through an opening 30 provided in the base material 3 (here, an insulating film 33 described later) as shown in FIG. It is in contact with the adsorbent 1. In FIG. 1, only the first electrode 21 is in contact with the gas adsorbent 1 through the opening 30, but the second electrode 22 is also in contact with the gas adsorbent 1 through the opening 30. That is, the electrode 2 and the gas adsorbent 1 are mechanically and electrically connected through an opening 30 provided in the base material 3. On the other hand, in the portion of the base material 3 where the opening 30 is not provided, the electrode 2 and the gas adsorbent 1 are mechanically and electrically separated by the base material 3. As shown in FIG. 3, a plurality of openings 30 (three in FIG. 3) are provided dispersed in a portion of the base material 3 facing the first electrode 21. Further, as shown in FIG. 3, a plurality of openings 30 (four in FIG. 3) are provided dispersed in a portion of the base material 3 facing the second electrode 22.

As described above, in the present embodiment, since the electrode 2 is electrically connected to the gas adsorbent 1 through the opening 30, it is compared with the case where the entire electrode 2 is electrically connected to the gas adsorbent 1. Therefore, the conductive path that can exist between the pair of electrodes 2 can be limited. As a result, in the present embodiment, an effect of reducing noise can be expected as compared with the case where the entire electrode 2 is electrically connected to the gas adsorbent 1.

The base material 3 is plate-shaped and is formed of a material having electrical insulation. In the present embodiment, the base material 3 is formed of an inorganic material such as _{silicon dioxide (SiO 2).} An insulating film 33 formed of an electrically insulating material is arranged on the surface of the base material 3. The insulating film 33 covers the entire surface of the base material 3 except for the plurality of openings 30.

In the gas sensor 100, by applying a voltage or passing an electric current between the first pad 31 and the second pad 32, the conductive path including the first electrode 21, the second electrode 22, and the gas adsorbent 1 is formed. , A current corresponding to the electric resistance of the gas adsorbent 1 flows. Therefore, by measuring this current, it is possible to measure the change in the electric resistance of the gas adsorbent 1. Then, based on the change in the electric resistance of the gas adsorbent 1, it is possible to detect the volatile organic compound A1 adsorbed on the gas adsorbent 1. For example, the volatile organic compound A1 adsorbed on the gas adsorbent 1 is detected by measuring the current flowing through the conductive path while a constant voltage is applied between the first pad 31 and the second pad 32. Is possible. Further, for example, the volatile organic compound A1 adsorbed on the gas adsorbent 1 is also detected by measuring the amount of voltage drop in the conductive path while a constant current is passed through the first pad 31 and the second pad 32. It is possible.

(3) Manufacturing Method Hereinafter, the manufacturing method of the gas adsorbent 1 (gas sensor 100) of the present embodiment will be briefly described. In the following, it is assumed that a pair of electrodes 2 are already arranged on the base material 3. Further, in the following, among the methods for manufacturing the gas sensor 100, the process of forming the gas adsorbent 1 will be mainly described.

The gas adsorbent 1 is formed by applying a solution to a portion of the surface of the base material 3 facing the first main piece 211 of the first electrode 21 and the second main piece 221 of the second electrode 22. The solution is a mixed solution containing conductive particles 11 and a polymer 12, which are materials constituting the gas adsorbent 1, and also containing a solvent. The solvent dissolves or disperses the polymer 12 and disperses the conductive particles 11. The solvent may contain at least one component selected from, for example, dimethyl sulfoxide, dimethylformamide, toluene, chloroform, acetone, acetonitrile, methanol, ethanol, isopropanol, tetrahydrofuran, ethyl acetate, butyl acetate and the like.

Specifically, the solution is applied to the surface of the base material 3 by using, for example, an inkjet method or a dispensing method. As a result, a film-like molded body is formed on the surface of the base material 3. Next, the molded product is heat-treated to volatilize the solvent contained in the molded product. As a result, the gas adsorbent 1 is formed on the surface of the base material 3.

Hereinafter, the advantages of the gas adsorbent 1 (gas sensor 100) of the present embodiment will be described with reference to FIG. FIG. 6 shows the experimental results of measuring the resistance change rate of various experimental materials (gas adsorbent 1) having different gas permeability coefficients of oxygen B1 of the polymer 12. Experiments on each experimental material are carried out under the same conditions. In each experimental material, the conductive particles 11 are carbon black. In FIG. 6, each of the plurality of circles has a one-to-one correspondence with a plurality of types of experimental materials. Further, in FIG. 6, the vertical axis represents the resistance change rate and the horizontal axis represents the gas permeability coefficient of oxygen B1.

The "resistance change rate" referred to in the present disclosure is the electricity of the gas adsorbent 1 in the state of adsorbing the volatile organic compound A1 with respect to the electric resistance of the gas adsorbent 1 in the state of not adsorbing the volatile organic compound A1. It represents the degree of change in resistance and is an actually measured value. The gas permeability coefficient of oxygen B1 is a theoretical value calculated by executing a simulation based on the molecular structure of the polymer 12.

As shown in FIG. 6, in the ^{experimental material in which the gas permeability coefficient of oxygen B1 is larger than 0.15 [cm 3} · cm / m ² · day · atm], the resistance change rate is 0.2 [%], which is almost the same. It has not changed. On the other hand, in the gas permeability coefficient of oxygen B1 is 0.15 ^{^{[cm 3 · cm / m 2 ·}} day · atm ] The following experimental materials, as the gas permeability coefficient of oxygen B1 decreases, the resistance change rate of exponential function Is increasing. In particular, the resistance conversion rate is remarkably increased in the region where the gas permeability coefficient of oxygen B1 is 0.1 [cm ³ · cm / m ² · day · atm] or less.

The above phenomenon will be examined below. When oxygen B1 is adsorbed on the gas adsorbent 1, it is considered that the surface of the conductive particles 11 is oxidized by oxygen B1. It is presumed that the formation of oxides on the surface of the conductive particles 11 makes it difficult to energize the conductive particles 11 and makes it difficult for the electrical resistance of the gas adsorbent 1 to change. Therefore, the smaller the gas permeation coefficient of oxygen B1 of the polymer 12, the more difficult it is for oxygen B1 to be adsorbed on the gas adsorbent 1, so that the surface of the conductive particles 11 is less likely to be oxidized, and as a result, the gas adsorbent It is presumed that the electrical resistance of 1 is likely to change.

By the way, the gas permeability coefficient of oxygen B1 and the gas permeability coefficient of the volatile organic compound A1 have a positive correlation. Therefore, as the gas permeability coefficient of oxygen B1 decreases, the gas permeability coefficient of the volatile organic compound A1 also decreases. In other words, it is considered that the more difficult it is for oxygen B1 to be adsorbed on the gas adsorbent 1, the more difficult it is for the volatile organic compound A1 to be adsorbed on the gas adsorbent 1. However, the inventors of the present application have adopted the polymer 12 containing molecules having a gas permeation coefficient of oxygen B1 of 0.15 [cm ³ · cm / m ^{2 · day · atm] or less as described above.} It was found that the electric resistance of the gas adsorbent 1 is likely to change even though the gas permeation coefficient of the volatile organic compound A1 is small.

Here, the detection accuracy of the volatile organic compound A1 in the gas adsorbent 1 depends on the measurement accuracy of the electrical resistance of the gas adsorbent 1. Therefore, it can be said that the larger the resistance change rate, the higher the detection accuracy of the volatile organic compound A1 in the gas adsorbent 1. Then, in the present embodiment, as described above, the gas permeability coefficient of oxygen B1 of the polymer 12 is 0.15 [cm ³ · cm / m ² · day · atm] or less (particularly 0.1 [cm ^3). · Cm / m ² · day · atm] or less), the resistance change rate is increasing.

Therefore, in the present embodiment, the polymer 12 contains ^{a molecule (specific molecule) having a gas permeability coefficient of oxygen B1 of 0.15 [cm 3} · cm / m ² · day · atm] or less. There is an advantage that the detection accuracy of the volatile organic compound A1 to be detected can be easily improved.

(4) Modified Example The above-described embodiment is only one of the various embodiments of the present disclosure. The above-described embodiment can be changed in various ways depending on the design and the like as long as the object of the present disclosure can be achieved. Hereinafter, modifications of the above-described embodiment will be listed. The modifications described below can be applied in combination as appropriate.

In the above-described embodiment, the polymer 12 may have a polar group. The polar group may include a carboxyl group, a hydroxy group, a nitrile group, a ketone group, an amino group, an imino group, a benzyl group, a cyano group, a nitro group and the like. In this aspect, an effect of suppressing the adsorption of oxygen B1 to the gas adsorbent 1 can be expected as compared with the case where the polymer 12 does not have a polar group.

In the above-described embodiment, the gas adsorbent 1 is formed in a circular shape in a plan view, but the present invention is not limited to this embodiment. For example, as shown in FIGS. 7 and 8, the gas adsorbent 1 may be formed in a rectangular shape in a plan view.

In the examples shown in FIGS. 7 and 8, the first main piece 211 of the first electrode 21 has a rectangular shape having a length in the left-right direction in a plan view, similarly to the first terminal 212. Further, the second main piece 221 of the second electrode 22 has a rectangular shape having a length in the left-right direction in a plan view, similarly to the second terminal 222. Further, a rectangular opening 30 having a length in the left-right direction in a plan view is provided at a position of the base material 3 facing the first main piece 211 and the second main piece 221. Then, the gas adsorbent 1 having a rectangular shape in a plan view is arranged on the base material 3 so as to cover these openings 30. Of course, the gas adsorbent 1 is not limited to a circular shape and a rectangular shape in a plan view, and may be formed in another shape.

In the above-described embodiment, the gas permeability coefficient of oxygen B1 is ^{represented by [cm 3} · cm / m ² · day · atm], but is not limited to this. For example, the unit of pressure in the gas permeability coefficient may be expressed as [Hg], [bar], or [Pa] instead of [atm]. Further, for example, the unit of length in the gas permeability coefficient may be [m], [in], or [mil]. Further, for example, the unit of time in the gas permeability coefficient may be [s]. When the gas permeability coefficient is expressed in another unit, the gas permeability coefficient of oxygen B1 is converted into a value corresponding to the converted unit.

In the above-described embodiment, the conductive particles 11 do not have to be dispersed in the polymer 12. For example, a layer containing the conductive particles 11 and a layer containing the polymer 12 may be separated, and a layer containing the conductive particles 11 may be formed on the layer containing the polymer 12.

In the above-described embodiment, the gas adsorbent 1 is partially in contact with the electrode 2 through the opening 30 in a plan view, but the present invention is not limited to this embodiment. For example, the gas adsorbent 1 may be entirely in contact with the electrode 2 in a plan view.

(summary)
As described above, the gas adsorbent (1) according to the first aspect is electrically connected to the electrode (2) in the gas sensor (100). The gas sensor (100) detects a gas containing at least the volatile organic compound (A1) to be detected. The gas adsorbent (1) contains conductive particles (11) and a polymer (12). The polymer (12) contains molecules having a gas permeability coefficient of oxygen (B1) of 0.15 [cm ³ · cm / m ² · day · atm] or less.

According to this aspect, there is an advantage that the detection accuracy of the volatile organic compound (A1) to be detected can be easily improved.

In the gas adsorbent (1) according to the second aspect, in the first aspect, the polymer (12) has a gas permeability coefficient of oxygen (B1) of 0.1 [cm ³ · cm / m ² · day ·. atm] Contains the following molecules.

According to this aspect, since the adsorption of oxygen (B1) can be easily suppressed, there is an advantage that the detection accuracy of the volatile organic compound (A1) to be detected can be further improved.

In the gas adsorbent (1) according to the third aspect, in the first or second aspect, the conductive particles (11) are dispersed in the polymer (12).

According to this aspect, there is an advantage that the electric resistance of the gas adsorbent (1) is likely to change regardless of where the volatile organic compound (A1) is adsorbed on the gas adsorbent (1).

In the gas adsorbent (1) according to the fourth aspect, in any one of the first to third aspects, the polymer (12) has a polar group.

The gas sensor (100) according to the fifth aspect includes a gas adsorbent (1) according to any one of the first to fourth aspects, an electrode (2) electrically connected to the gas adsorbent (1), and an electrode (2). To be equipped with.

The gas sensor (100) according to the sixth aspect further includes the base material (3) on which the electrode (2) is formed in the fifth aspect. The gas adsorbent (1) is arranged on the base material (3). The electrode (2) and the gas adsorbent (1) are electrically connected to each other through an opening (30) provided in the base material (3).

According to this aspect, there is an advantage that the effect of reducing noise can be expected as compared with the case where the entire electrode (2) is electrically connected to the gas adsorbent (1).

The configurations according to the second to fourth aspects are not essential configurations for the gas adsorbent (1) and can be omitted as appropriate. Further, the configuration according to the sixth aspect is not an essential configuration for the gas sensor (100) and can be omitted as appropriate.

100 Gas sensor 1 Gas adsorbent 11 Conductive particles 12 Polymer 2 Electrode 3 Base material 30 Opening A1 Volatile organic compound B1 Oxygen

Claims

Electrically connected to electrodes in a gas sensor that detects at least a gas containing volatile organic compounds to be detected
With conductive particles
A polymer containing a molecule having an oxygen gas permeability coefficient of 0.15 [cm 3 · cm / m 2 · day · atm] or less, and the like.
Gas adsorbent.
The polymer contains molecules having a gas permeability coefficient of oxygen of 0.1 [cm 3 · cm / m 2 · day · atm] or less.
The gas adsorbent according to claim 1.
The conductive particles are dispersed in the polymer.
The gas adsorbent according to claim 1 or 2.
The polymer has a polar group.
The gas adsorbent according to any one of claims 1 to 3.
The gas adsorbent according to any one of claims 1 to 4 and
The electrode comprising the electrode electrically connected to the gas adsorbent.
Gas sensor.
Further provided with a base material on which the electrodes are formed,
The gas adsorbent is placed on the substrate and
The electrode and the gas adsorbent are electrically connected through an opening provided in the base material.
The gas sensor according to claim 5.