JP7412293B2 - Sensors with receptors containing nitrogen atoms - Google Patents

Description

The present invention relates to a sensor having a receptor containing a nitrogen atom.

Generally, a sensor has a detection part (receptor) that enables highly sensitive and highly selective detection of a target substance to be detected. A wide variety of substances are used as receptors, including self-assembled membranes, monolayers, DNA/RNA, proteins, antigens/antibodies, and polymers. In the field of olfactory/gas sensors, new applications such as breath testing and odor management in hotels, cars, and factories are expected due to the recent development of AI and IoT. Additionally, if it becomes possible to track ethanol and aldehydes derived from anaerobic respiration in food, the quality of food can be controlled using sensors.
In Patent Document 1, a porous material or a granular material is coated on a sensor body of a type that detects a physical parameter, and a change in the physical parameter due to adsorption of the analyte molecules by the porous material or the granular material causes the analyte to be detected. Sensors for detecting molecules have been described.
Patent Document 2 discloses a detection device that detects a substance to be measured by adsorbing it, and includes two or more detection units that adsorb the substance to be measured, and the two or more detection units have a unit of D or a unit of T. a first detection part containing a first compound containing a siloxane bond of a unit and a hydrocarbon group or a heteroatom-containing hydrocarbon group; a siloxane bond of a D unit or a T unit and a hydrocarbon group or a heteroatom-containing hydrocarbon group; and a second detection section containing a second compound different from the first compound, wherein the first detection section and the second detection section have different compounds for adsorption of the same substance to be measured. A detection device is described that is characterized in that it outputs an electrical signal.
Patent Document 3 discloses that silica particles have amino groups useful for bonding biomolecules, etc. on the particle surface, and the amino groups are adsorbed to the silica particle surface, thereby reducing reactivity with the biomolecules, etc. A method for producing silica particles, the silica particles, and composite particles using the same are described.

International Publication No. 2016/121155 pamphlet International Publication No. 2018/230382 pamphlet JP2009-274923A

Although the technology described in Patent Document 1 achieves high sensitivity, selectivity, and stability, the electrical signal is greatly attenuated outside of a dry atmosphere, greatly limiting the environments in which it can be used as an olfactory sensor.
The technology described in Patent Document 2 realizes a method for selectively measuring multiple types of target substances using a simple method. The body is deformed and reproducible signals cannot be obtained.
The technology described in Patent Document 3 can produce silica particles that bind with biomolecules with high reactivity, has excellent dispersion stability, has high reproducibility of measurement results as an analytical reagent, and is suitable for high-sensitivity analysis of extremely small amounts of target samples. However, its use is limited to analytical reagents that target the biomolecules and physiologically active substances mentioned above.

The present invention has been made in view of the above-mentioned problems with the prior art, and its purpose is to provide a sensor that can measure highly hydrophilic gases such as aldehydes with high sensitivity even under humid conditions. Our goal is to provide the following.

The inventors of the present application have diligently studied and conducted repeated experiments to solve the above-mentioned problems, and as a result, they have found that the receptor contains an organic-inorganic hybrid structure represented by a specific formula containing nitrogen and has a specific porosity. As a result, the inventors have unexpectedly discovered that the above-mentioned problem can be solved, and have completed the present invention.
That is, the present invention includes the following aspects.
[1]
The following formula (1)
RSiO _3/2 (1)
(In formula (1), R represents an organic group containing at least one nitrogen atom)
A sensor comprising an organic-inorganic hybrid having a structure shown in the following, and having a receptor having a porosity of 3% or less.
[2]
The sensor according to [1] above, wherein R has an amino group or a heterocycle containing a nitrogen atom.
[3]
The sensor according to [1] or [2] above, wherein R has a tertiary amino group.
[4]
The sensor according to any one of [1] to [3] above, wherein R has at least one aromatic ring.
[5]
The sensor according to [4] above, wherein the aromatic ring is directly bonded to a Si atom.
[6]
The sensor according to any one of [1] to [5] above, wherein R has a copolymerized structure of an aromatic ring and a non-aromatic ring.
[7]
The sensor according to any one of [1] to [6] above, wherein the receptor contains a filler.
[8]
The sensor according to [7] above, wherein the filler is an inorganic filler.
[9]
The sensor according to [7] or [8] above, wherein the filler is a metal oxide.
[10]
The sensor according to any one of [7] to [9] above, wherein the filler is silica.
[11]
The sensor according to any one of [7] to [10] above, wherein the filler is spherical or chain-shaped.
[12]
The sensor according to any one of [1] to [11] above, which contains the filler in a volume fraction of 1 to 70%.
[13]
The sensor according to any one of [1] to [12] above, which contains the filler in a volume fraction of 3 to 40%.
[14]
The sensor according to any one of [1] to [13] above, wherein the receptor has a thermogravimetric reduction rate of 65% by weight or less.

According to the present invention, highly hydrophilic gases such as aldehydes can be measured with high sensitivity even under humid conditions.

An example of an optical micrograph of a chip coated with a receptor is shown.

Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail, but the present invention is not limited thereto, and various modifications can be made without departing from the gist thereof. It is.

The sensor of this embodiment has the following formula (1)
RSiO _3/2 (1)
(In formula (1), R represents an organic group containing at least one nitrogen atom)
It contains an organic-inorganic hybrid having the structure shown in and has a receptor with a porosity of 3% or less.

The sensor of this embodiment is a sensor having a receptor to which a substance to be detected is adsorbed and diffused into the membrane, and the receptor includes an organic-inorganic hybrid having a structure represented by RSiO _3/2 . The above R is an organic group containing at least one nitrogen atom, and the porosity as a volume fraction of the receptor is 3% or less.

With the receptor configured in this way, the sensor of this embodiment can measure aldehyde gases such as acetaldehyde with high sensitivity even under humid conditions. Furthermore, even after reflow treatment and after long-term use, there is no deterioration of the receptor and measurements can be continued.

The sensor of this embodiment includes, but is not particularly limited to, a sensor body of a type that detects physical parameters, for example. Physical parameters include, but are not limited to, surface stress, stress, force, surface tension, pressure, mass, elasticity, Young's modulus, Poisson's ratio, resonance frequency, frequency, volume, thickness, viscosity, density, magnetic force, and magnetism. quantity, magnetic field, magnetic flux, magnetic flux density, electrical resistance, electrical quantity, permittivity, power, electric field, charge, current, voltage, potential, mobility, electrostatic energy, capacitance, inductance, reactance, susceptance, admittance, impedance, conductance , plasmons, refractive index, luminosity and temperature and various other physical parameters.

The sensor of this embodiment is, for example, a sensor in which a receptor (referred to as a "receptor layer" or a "sensitive film" depending on the shape, etc.) is provided directly on the sensor body. That is, in the sensor of this embodiment, the sensor body can detect changes in physical parameters caused by the receptor adsorbing and internally diffusing the detection target substance (analyte molecule). . As mentioned above, the sensor body that can be used in the sensor of this embodiment is one that detects changes caused in the receptors arranged on the surface of the receptors when they adsorb and internally diffuse the substance to be detected. If so, there are no particular limitations.

When the sensor of this embodiment is applied to, for example, a surface stress sensor (for example, an olfactory sensor), a detection target substance is adsorbed to a receptor (sensitive membrane) that covers at least a portion of the surface of the sensor body, Furthermore, by internally diffusing into the receptor, the body detects the stress change caused in the receptor and outputs a signal.

Furthermore, as another type of sensor main body, for example, a QCM device can be applied. QCM devices measure minute changes in mass by utilizing the property that when a substance is adsorbed to the electrode surface of a crystal oscillator to which an alternating electric field is applied, the resonance frequency decreases depending on the mass and viscoelasticity of the adsorbate. It is a mass sensor and can perform in-situ measurements. When applying the sensor of this embodiment as a QCM device, for example, by forming the receptor of this embodiment on the surface of an electrode, the mass change caused by the adsorption of the detection target substance by the receptor can be absorbed by the sensor body. Detect and output a signal. Further, various conductive materials can be used as electrodes of QCM, but when the receptor in this embodiment is made to have conductivity, the receptor can also be used as an electrode of QCM.

In this specification, the term "adsorption" is used to include the phenomenon in which the concentration of another substance (which becomes an adsorbate) increases at the interface of a certain object compared to the surrounding area, and physical adsorption alone is not sufficient. It also includes chemisorption due to chemical bonds and biochemical actions.

[Receptor]
The receptor in this embodiment can induce a change in signal by adsorbing and internally diffusing adsorbates (substances to be detected) such as odor molecules and gas molecules. In particular, membrane-shaped receptors are also referred to as "sensitive membranes."

Gases that can be measured by the sensor of this embodiment include redox gases, combustible gases, water vapor, and volatile organic substance (VOC) gases, and the selectivity of gas molecules is determined by the molecular skeleton and copolymerization ratio. Can be easily changed. More specifically, hydrocarbons, nitrogen oxides, sulfur oxides, carbon monoxide, carbon dioxide, hydrogen, oxygen, alcohols, amines, aldehydes, unsaturated aldehydes, ketones, esters, halomethanes, volatile aromatic compounds, Examples include volatile heterocyclic aromatic compounds. Hydrocarbons include methane, ethane, propane, butane, isobutane, ethylene, etc. Alcohols include methanol, ethanol, isopropanol, higher alcohols, and amines include ammonia, dimethylamine, trimethylamine, triethylamine, etc. Aldehydes include formaldehyde, acetaldehyde, etc., unsaturated aldehydes include octenal, nonenal, hexenal, etc., ketones include acetone, etc., halomethanes include chloroform, dichloromethane, etc., and volatile Examples of the aromatic compound include benzene, toluene, xylene, naphthalene, etc., and examples of the volatile heterocyclic aromatic compound include indole, skatole, etc.

In the sensor of this embodiment, from the viewpoint of sensitivity and stability in a humid environment, the porosity as a volume fraction of the receptor is 3% or less. From the viewpoint of further improving sensitivity, the porosity is more preferably 2% or less, and from the viewpoint of suppressing a decrease in sensitivity in a humid environment, the porosity is even more preferably 1% or less.

The porosity can be adjusted within the above range by, for example, adjusting the ratio of the filler to the structure represented by RSiO _3/2 . Further, the porosity is a value measured by the method described in the Examples of this specification or a method understood by those skilled in the art to be equivalent thereto.

The sensor of this embodiment is expressed by formula (1)
RSiO _3/2 (1)
(In formula (1), R represents an organic group containing at least one nitrogen atom)
Contains the structure shown in .

R is an organic group containing at least one nitrogen atom, and by including one or more nitrogen atoms in the organic group, the response sensitivity to highly hydrophilic gases such as aldehyde is improved. The aldehyde adsorbed by the receptor of this embodiment is not particularly limited, but includes formaldehyde, acetaldehyde, and the like.

Specific examples of organic groups containing one or more nitrogen atoms represented by R include, but are not limited to, amino groups, amide groups, urethane bonds, urea bonds, imide groups, imine groups, aziridine, azetidine, pyrrolidine, etc. , pyrrole, piperidine, piperazine, pyridine, hexamethyleneimine, azadopyrrolidene, imidazole, pyrazole, oxazole, isoxazole, thiazole, imidazoline, morpholine, thiazine, triazole, tetrazole, pyridazine, pyrimidine, pyrazine, indole, isoindole, benzimidazole, Examples include substituents having a heterocyclic structure containing a nitrogen atom, such as purine, benzotriazole, quinoline, isoquinoline, quinazoline, quinoxaline, cinnoline, pteridine, carbazole, adenine, guanine, cytosine, thymine, and uracil. The present inventors have found that particularly when the organic group contains a nitrogen atom, it has a high sensitivity specific to aldehydes such as acetaldehyde even under humid conditions. The reason may be as follows, but is not intended to be limited to the following. In other words, the unshared electron pair of the nitrogen atom attacks the carbonyl carbon of the aldehyde, and the electron pair of the carbon-oxygen double bond is transferred to the oxygen, resulting in an equilibrium reaction between the aldehyde and nitrogen. This is presumed to be because it induces specific swelling of the receptor because it occurs between atoms.

Moreover, it is preferable that R has an amino group or a heterocycle containing a nitrogen atom. That is, it is preferable from the viewpoint of synthesis and reagent availability that the nitrogen atom contained in the organic group is contained in an amino group or a heterocyclic structure.

Furthermore, it is preferable that R has a tertiary amino group. That is, when the nitrogen atom contained in the organic group is contained in the tertiary amino group, it is preferable from the viewpoint of selectivity for highly hydrophilic gases such as aldehydes.

Furthermore, it is preferable that R has at least one type of aromatic ring. That is, when R contains an aromatic ring, the humidity resistance of the sensor tends to be further improved. The aromatic ring is not particularly limited as it can be selected appropriately considering the use of the sensor, etc., but examples include aromatic hydrocarbon groups such as phenyl group, naphthyl group, p-tolyl group, and biphenyl group, 4-chlorophenyl group, Substituted aromatic hydrocarbon groups such as 4-fluorophenyl group, 4-bromophenyl group, 4-iodophenyl group, 4-methoxyphenyl group, 4-aminophenyl group, pentafluorophenyl group, 3-furyl group, 3- Examples include heterocyclic hydrocarbon groups such as thienyl group, 2-pyridyl group, 3-pyridyl group, and 4-pyridyl group, and metallocenes such as ferrocenyl group. The organic group represented by R in the sensor of this embodiment may contain one type of the above-mentioned aromatic ring alone, or may contain two or more types in combination.

When R contains an aromatic ring, an alkyl group (having 1 to 18 carbon atoms), an ether group, a carbonyl group, a carboxyl group, an amide group, a urethane bond, or a urea bond is present between the aromatic ring and the Si atom. Although a spacer structure such as a bond, an imide group, or an imine group may be interposed, from the viewpoint of responsiveness and sensitivity, it is preferable that these spacers are not interposed and the aromatic ring is directly bonded to the Si atom.

The organic group represented by R in the sensor of this embodiment has a copolymer structure of an aromatic ring and a non-aromatic ring from the viewpoint of achieving both humidity resistance and selectivity to various gas molecules (substances to be detected). It is preferable to include.

In addition, from the viewpoint of responsiveness to highly polar gases and odor molecules, the organic group represented by R includes halogen atoms such as nitrogen atoms, oxygen atoms, sulfur atoms, fluorine, chlorine, bromine, and iodine atoms, boron atoms, It is preferable that the organic functional group contains one or more atoms selected from the group consisting of Among these, from the viewpoint of stability, the organic group represented by R includes an organic functional group containing one or more atoms selected from the group consisting of nitrogen atom, oxygen atom, sulfur atom, and fluorine atom. It is preferable.

Specific examples of organic functional groups include, but are not limited to, linear or branched hydrocarbon groups that may have substituents such as halogen atoms (for example, straight chain or branched hydrocarbon groups such as 3-chloropropyl group and octyl group). chain or branched C _1-8 alkyl group), alicyclic hydrocarbon groups that may have substituents such as halogen atoms (for example, C _5-6 cycloalkyl groups such as cyclohexyl group), halogen atoms, etc. Aromatic hydrocarbon groups that may have substituents (e.g., phenyl group, pentafluorophenyl group, etc.), vinyl groups, allyl groups, (meth)acrylic groups, (meth)acryloyloxyalkyl groups (e.g., (meth) ) (meth)acryloyloxy C _1-3 alkyl group such as acryloyloxypropyl group), epoxy group, glycidyloxyalkyl group (e.g. glycidyloxy C _1-3 alkyl group such as 3-glycidyloxypropyl group), (epoxy cycloalkyl)alkyl group (for example, 2-(3,4-epoxycyclohexyl)ethyl group, etc.), hydroxy group, ether group, carbonyl group, carboxyl group, ester group, urethane group, urea group, mercapto group, mercaptoalkyl group (e.g. mercapto C _1-3 alkyl group such as mercaptopropyl group), sulfide group, amino group (e.g. primary amino group, secondary amino group, tertiary amino group), aminoalkyl group (e.g. aminopropyl group) (aminoalkylamino)alkyl group (e.g., 3-(2-aminoethylamino)propyl group), imidazolyl group _, imidazolylalkyl group (e.g., 3-(2-imidazoline- 1-yl)propyl group), alkylaminoalkyl group (for example, 3-(dimethylamino)propyl group), amide group, heterocyclic aromatic group, oxime group, imide group, imine group, halogen group, nitrile group, phosphone group, phosphate group, etc. Among these, from the viewpoint of availability, organic functional groups include linear or branched hydrocarbon groups that may have substituents, alicyclic hydrocarbon groups that may have substituents, and organic functional groups that may have substituents. Aromatic hydrocarbon groups that may have, vinyl groups, allyl groups, (meth)acryloyloxyalkyl groups, glycidyloxyalkyl groups, (epoxycycloalkyl)alkyl groups, mercaptoalkyl groups, aminoalkyl groups, (aminoalkylamino) ) is preferably one or more selected from the group consisting of an alkyl group, an imidazolylalkyl group, an alkylaminoalkyl group, and a hydroxy group. These functional groups may be used alone or in combination of two or more.

The organic functional group is preferably an organic functional group derived from a silane coupling agent. Examples of the silane coupling agent include hydrolyzable metal oxides such as alkoxysilane, acetoxysilane, and chlorosilane. Among these, the hydrolyzable metal oxide is preferably an alkoxysilane from the viewpoint of ease of handling and versatility of the functional group, and more preferably a trifunctional alkoxysilane from the viewpoint of reactivity.

Trifunctional alkoxysilanes may be copolymerized with mono-, di-, or tetra-functional alkoxysilanes, but from the viewpoint of increasing the Young's modulus of the organic-inorganic hybrid and increasing its sensitivity, tetrafunctional alkoxysilanes are preferable. Copolymerization with is preferred.

As the trifunctional alkoxysilane, a silane coupling agent having a methoxy group, ethoxy group, isopropoxy group, or butoxy group in the alkoxy group can be used.

Commercially available aromatic silane coupling agents include phenyltrialkoxysilane, nitrobenzenamidetrialkoxysilane, benzyltrialkoxysilane, 4-chlorophenyltrialkoxysilane, phenylaminopropyltrialkoxysilane, 4-aminophenyltrialkoxysilane, Naphthyltrialkoxysilane, 4-methoxytrialkoxysilane, pentafluorophenyltrialkoxysilane, ferrocenyltrialkoxysilane, biphenyltrialkoxysilane, 3-furyltrialkoxysilane, 3-thienyltrialkoxysilane, 2-pyridyltrialkoxysilane , 3-pyridyltrialkoxysilane, 4-pyridyltrialkoxysilane, etc., but are not limited thereto.

Commercially available non-aromatic silane coupling agents include 3-(2-aminoethylamino)propyltrialkoxysilane, 3-mercaptopropyltrialkoxysilane, vinyltrialkoxysilane, cyclohexyltrialkoxysilane, and 3-glycidyloxypropyl. Trialkoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrialkoxysilane, 3-(dimethylamino)propyltrialkoxysilane, 3-(2-imidazolin-1-yl)propyltrialkoxysilane, 3-aminopropyl Trialkoxysilane, 3-(methacryloyloxy)propyltrialkoxysilane, 3-(acryloyloxy)propyltrialkoxysilane, allyltrialkoxysilane, methyltrialkoxysilane, ethyltrialkoxysilane, propyltrialkoxysilane, butylalkoxysilane, Hexyltrialkoxysilane, octyltrialkoxysilane, decyltrialkoxysilane, dodecyltrialkoxysilane, octadecyltrialkoxysilane, 3-ureidopropyltrialkoxysilane, cyclohexylaminopropyltrialkoxysilane, hexafluorophenyltrialkoxysilane, 3-chloro Propyltrialkoxysilane, 3-bromopropyltrialkoxysilane, 3-piperazinopropyltrialkoxysilane, 3-morpholinopropyltrialkoxysilane, 3-allylaminopropyltrialkoxysilane, norbornyltrialkoxysilane, piperidine Examples include, but are not limited to, nopropyltrialkoxysilane.

When copolymerizing two or more types of silane coupling agents, the ratio of the aromatic silane coupling agent to the non-aromatic silane coupling agent is preferably 1:10 to 1:5 in terms of molar ratio, and heat resistance From this point of view, the ratio is preferably 1:5 to 1:1, and from the viewpoint of suppressing reduction in signal intensity under humidity, the ratio is preferably 1:1 to 10:1.

The organic functional groups in the sensor of this embodiment can be identified by subjecting the receptors on the sensor body to surface element analysis such as SEM-EDX, XPS, and ATR.

[Filler]
The receptor in this embodiment may contain a filler. When the receptor contains a filler, it tends to improve the Young's modulus of the organic-inorganic hybrid and increase the sensitivity of the sensor. The volume fraction of the filler contained in the receptor is preferably 1% or more from the viewpoint of crack resistance, and preferably 3% or more from the viewpoint of sensitivity. On the other hand, if it exceeds 70%, the sensitivity of the sensor tends to decrease due to response relaxation due to the voids between fillers, so it is preferably 70% or less. From the viewpoint of performance, it is more preferably 40% or less.

The filler is not particularly limited and can be selected from various known fillers. Specific examples include, but are not limited to, polymer beads such as polystyrene, polymethyl methacrylate, and polyphenylene oxide, spherical particles such as acrylic latex, metal nitrides such as silicon nitride, silica, zirconia, titania, zinc oxide, and Metal oxides such as aluminum and tin oxide, composite metal compounds such as barium titanate, strontium titanate, and ITO, inorganic metal fillers such as gold, silver, copper, palladium, platinum, iron, and aluminum, carbon nanotubes, graphene, and carbon. One or more carbon materials selected from carbon materials such as black, carbon dots, and nanocarbon can be included.

The filler is preferably an inorganic filler from the viewpoint of dispersibility and coatability. From the same viewpoint, fillers are preferably metal oxides such as silica, zirconia, titania, and alumina, and inorganic metal fillers such as gold, silver, copper, palladium, platinum, iron, and aluminum. Metal oxides such as silica and zirconia are more preferable because they have less influence on attenuation, and silica is even more preferable from the economic point of view. The present inventors have found that, especially when silica is used, the attenuation of the response of common hydrophilic gases such as ethanol and acetaldehyde is improved even in humid conditions. The reason may be as follows, but is not intended to be limited to the following. In other words, the silica skeleton and the hydroxyl groups bonded to the silicon atoms are relatively hydrophobic compared to the titania skeleton or the hydroxyl groups bonded to the titanium atoms of Patent Document 1, so that highly hydrophilic water molecules can be adsorbed. It is presumed that inhibition is suppressed.

The shape of the filler is not particularly limited, and may form a unique tissue structure such as a sphere, bead, chain, hollow, ellipsoid, fiber, rod, cylinder, needle, plate, etc. You can. The shape of the filler is preferably spherical, rod-like, plate-like, fibrous, or a combination of two or more of these, and more preferably spherical or chain-like. Note that the spherical shape herein means not only a true spherical shape but also a substantially spherical shape including a spheroid, an oval, and the like. It is particularly preferable that the filler is spherical from the viewpoint of crack resistance.

The metal oxide as a filler may be produced, for example, by a sol-gel method using a metal oxide precursor having a tetrafunctional hydrolyzable group such as alkoxy or chloro, or a commercially available product may be used. . Examples of the metal oxide precursor having a tetrafunctional hydrolyzable group include tetraalkoxysilane, tetrachlorosilane, tetraalkoxytitanium, and tetraacetoxyzirconium. These tetrafunctional hydrolyzable metal inorganic oxides may be copolymerized with trifunctional hydrolyzable metal oxides, and the shape can be changed by adjusting the concentration, temperature, pH, water content, etc. of the reaction system. can be controlled. Note that, for example, when a filler is manufactured by emulsion polymerization, a structure represented by RSiO _3/2 may be obtained on the filler side, but a filler having such a structure in the receptor in this embodiment shall be treated as an organic-inorganic hybrid in the sensor of this embodiment.

Commercially available fillers include the LEVASIL series (manufactured by H.C. Starck Co., Ltd.), the Quatron PL series (manufactured by Fuso Chemical Co., Ltd.), the OSCAL series (manufactured by Catalysts Kasei Kogyo Co., Ltd.); powder form; Examples of the silica particles include Aerosil 130, Aerosil 300, Aerosil 380, Aerosil TT600, Aerosil OX50 (manufactured by Nippon Aerosil Co., Ltd.), Sildex H31, Sildex H32, Sildex H51, Aerosil H52, Aerosil H121, Aerosil H122 (all manufactured by Nippon Aerosil Co., Ltd.). IPA-ST, IPA -ST-L, IPA-ST-ZL, MEK-ST-2040 ST-XS, ST-S, ST-30, ST-50T, ST-30L, ST-YL, ST-ZL, MP-1040, MP- 2040, MP-4540M, ST-OXS, ST-OS, ST-O, ST-O-40, ST-OL, ST-OYL, ST-NXS, ST-NS, ST-N, ST-N-40, ST-CXS, ST-C, ST-CM, ST-AK, ST-AK-L, ST-AK-YL, OZ-S30K, SZ-S30K-AC, OZ-S30M, Cernax CX-S505M, IPA- ST-UP, MEK-ST-UP, ST-UP, ST-PS-S, ST-PS-M, ST-OUP, ST-PS-SO, ST-PS-MO, ST-AK-PS-S, etc. (manufactured by Nissan Chemical Co., Ltd.), SRD-K, SRD-M, SXR-CM, SZR-K, and SZR-M (manufactured by Sakai Chemical Co., Ltd.). Examples of powder fillers include Aerosil 130, Aerosil 300, Aerosil 380, Aerosil TT600, Aerosil OX50 (manufactured by Nippon Aerosil Co., Ltd.), Sildex H31, Sildex H32, Sildex H51, Aerosil H52, Aerosil H121, Sildex Examples include H122 (manufactured by Asahi Glass Co., Ltd.), E220A, E220 (manufactured by Nippon Silica Kogyo Co., Ltd.), SYLYSIA470 (manufactured by Fuji Silicia Co., Ltd.), SG flakes (manufactured by Nippon Sheet Glass Co., Ltd.), etc. Can be done. Moreover, the surface of these fillers can be chemically modified and used.

[Method for manufacturing organic-inorganic hybrid]
Formula (1)
RSiO _3/2 (1)
(In formula (1), R represents an organic group containing at least one nitrogen atom)
The method for producing an organic-inorganic hybrid having the structure shown in is not particularly limited, but it is mainly produced using a sol-gel method. Specifically, a hydrolyzable silane compound (including a silane coupling agent) is treated in the presence of water under acidic and basic conditions using a sol-gel method to form a condensate of a silane coupling agent, that is, RSiO An organic-inorganic hybrid containing a structure represented by _3/2 can be obtained. As the organic-inorganic hybrid in this embodiment, one having a cage-shaped, ladder-shaped, or random-type molecular skeleton can be used, and a mixture thereof can also be used.

In the production of an organic-inorganic hybrid, it is more preferable to hydrolyze, condense, and surface modify the silane coupling agent in the presence of a catalyst from the viewpoint of being able to control the reaction rates of hydrolysis and condensation.

Types of catalysts include acid catalysts and base catalysts.
Examples of acid catalysts include inorganic acids and organic acids. Examples of inorganic acids include, but are not limited to, hydrochloric acid, nitric acid, sulfuric acid, hydrofluoric acid, phosphoric acid, boric acid, and the like. Examples of organic acids include, but are not limited to, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oxalic acid, maleic acid, methylmalonic acid, and benzoic acid. Acid, p-aminobenzoic acid, p-toluenesulfonic acid, benzenesulfonic acid, trifluoroacetic acid, formic acid, malonic acid, sulfonic acid, phthalic acid, fumaric acid, citric acid, tartaric acid, citraconic acid, malic acid, glutaric acid, etc. can be mentioned.
Examples of the base catalyst include inorganic bases and organic bases. Examples of inorganic bases include, but are not limited to, alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide, and cesium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide; and carbonic acid. Alkali or alkaline earth metal carbonates such as lithium, potassium carbonate, and sodium carbonate; metal hydrogen carbonates such as potassium hydrogen carbonate and sodium hydrogen carbonate; and the like. Examples of organic bases include, but are not limited to, aqueous ammonia, trialkylamines such as triethylamine and ethyldiisopropylamine; N,N- carbon atoms having 1 to 4 carbon atoms such as N,N-dimethylaniline and N,N-diethylaniline; Dialkylaniline derivatives; pyridine derivatives which may have an alkyl substituent having 1 to 4 carbon atoms, such as pyridine and 2,6-lutidine; and the like. These catalysts can be used alone or in combination of two or more.

In the production of organic-inorganic hybrids, it is preferable in terms of reaction efficiency to add a catalyst in an amount that brings the pH of the reaction system to a range of 0.01 to 6.0, or to a pH of 8 to 14. It is more preferable to carry out the sol-gel reaction under basic conditions of pH 8 to 14.

Hydrolysis and condensation to produce organic-inorganic hybrids can also be carried out in organic solvents. Examples of organic solvents that can be used in the condensation reaction include alcohols, esters, ketones, ethers, aliphatic hydrocarbon compounds, aromatic hydrocarbon compounds, and amide compounds.

Examples of the alcohol include, but are not limited to, monohydric alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and butyl alcohol; ethylene glycol, diethylene glycol, propylene glycol, glycerin, trimethylolpropane, and hexanetriol. Polyhydric alcohol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene Examples include monoethers of polyhydric alcohols such as glycol monoethyl ether, propylene glycol monopropyl ether, and propylene glycol monobutyl ether.

Examples of the ester include, but are not limited to, methyl acetate, ethyl acetate, butyl acetate, γ-butyrolactone, and the like.

Examples of the ketone include, but are not limited to, acetone, methyl ethyl ketone, methyl isoamyl ketone, and the like.

In addition to the monoethers of polyhydric alcohols mentioned above, examples of the above-mentioned ethers include ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, and propylene glycol dibutyl ether. Examples include polyhydric alcohol ethers in which all the hydroxyl groups of a polyhydric alcohol are alkyl etherified, such as glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, and diethylene glycol diethyl ether; tetrahydrofuran; 1,4-dioxane; anisole; and the like.

Examples of the aliphatic hydrocarbon compound include, but are not limited to, hexane, heptane, octane, nonane, decane, and the like.

Examples of the aromatic hydrocarbon compound include, but are not limited to, benzene, toluene, xylene, etc.

Examples of the amide compound include, but are not limited to, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, and the like.

Among the above-mentioned solvents, alcohols include methanol, ethanol, isopropanol, butanol, etc.; ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.; ethers include ethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, etc. ; and as the amide compound, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc. are preferred because they are easily mixed with water. These solvents may be used alone or in combination.

When blending a filler with an organic-inorganic hybrid, the organic-inorganic hybrid may be produced in the presence of the filler, or the filler may be blended with the produced organic-inorganic hybrid. In this case, the organic-inorganic hybrid may be prepared by dissolving a condensate of a silane coupling agent in a commercially available dispersion filler, dispersing the filler and silane coupling agent in a ball mill, jet mill, etc. Although it can be manufactured by simultaneously condensing a silane and a filler, a manufacturing method in which an alkoxysilane and a filler are simultaneously condensed is more preferable in terms of improving the solvent dispersibility of the filler and improving the inkjet coating properties. When a colloidal filler is treated by the sol-gel method in the presence of a silane coupling agent, the condensate of the silane coupling agent modifies the surface of the filler and is arranged so as to fill in the gaps. The amount of pores can be adjusted by adjusting the amount arbitrarily. When a hydroxyl group exists on the filler surface, the surface hydroxyl group and the hydroxyl group generated by hydrolysis of alkoxysilane interact and form an ether bond through a condensation reaction, which can increase the compatibility between the filler and the condensate. , a more stable receptor can be obtained.

Surface modification of the organic group represented by R on the filler is carried out by surface modification while the filler is dispersed in a dispersion medium. Specifically, for example, an organic-inorganic hybrid is produced by a step of adding the above silane coupling agent to a homogeneous dispersion of a metal oxide containing alcohol and water in the presence of a catalyst.

The organic-inorganic hybrid may be recovered by separating the precipitate or gel by centrifugation or filtration, or it may be isolated by removing the volatile solvent using an evaporator or the like.

Introduction of the organic group represented by R can be confirmed by FT-IR or elemental analysis. It can also be confirmed by thermogravimetric loss measurement. The thermogravimetric loss rate of the receptor from 150°C to 1000°C is preferably 3% to 75% by weight from the viewpoint of sensitivity, and from 5% to 65% by weight from the viewpoint of humidity resistance. The content is more preferably 5% by weight to 60% by weight from the viewpoint of thermal stability.

Since the receptor in this embodiment has a membrane shape, the measurement accuracy of the sensor tends to be stable. When the organic-inorganic hybrid has a film shape, the preferred film thickness may be a shape in which the organic-inorganic hybrid has a homogeneous film thickness distribution, or a coffee ring-like shape in which the film thickness is thicker at the edges. good. A film with a coffee ring shape does not deteriorate in shape even when exposed to high-concentration VOC vapor, has excellent structural stability, and has higher sensitivity than a film structure consisting of a flat structure. This is preferable because it is a trend. The reason may be as follows, but is not intended to be limited to the following. When the sensor is a surface stress sensor, if a coffee ring type film is placed on the surface stress sensor, more film volume will be placed near the piezo, and the stress caused by its deformation will be more efficiently propagated to the piezo element. It is believed that high sensitivity can be achieved. As a coffee ring type, a cross-sectional profile between two points on the diameter of a circularly formed film is obtained, and it is determined from the cross-sectional profile that the film thickness at the center is 80% or less of the film thickness at the maximum part. It is preferable from the viewpoint of sensitivity reproducibility, more preferably 60% or less from the viewpoint of sensitivity, and more preferably 40% or less from the viewpoint of maximizing response sensitivity. In the case of a coffee ring-like shape, the thickness of the thinnest part at the center of the film and the thickest part at the end portions is usually preferably 10 nm or more and 50 μm or less, respectively. The film thickness is preferably 10 nm or more and 30 μm or less from the viewpoint of shortening the time required for drying during manufacturing and increasing productivity, and more preferably 10 nm or more and 20 μm or less from the viewpoint of increasing sensitivity. Moreover, it is preferable that the maximum thickness of the receptor in this embodiment is 30 μm or less.

When the sensor in which the sensor body is coated with the receptor in this embodiment is used as an olfactory sensor, the organic functional group and gas molecules interact in the gas phase, and the gas molecules are adsorbed to or internally diffused into the receptor. Preferably, stress is generated by the gas and the gas is detected thereby.

[Surface stress (MSS) sensor]
The sensor of this embodiment can be applied, for example, to a surface stress sensor, and more specifically, can be used as a membrane-type surface stress (MSS) sensor. In that case, a receptor covering at least a portion of the surface of the sensor body adsorbs the detection target substance, detects a stress change caused in the receptor, and the body outputs a signal. The surface stress sensor is preferably a four-point fixed piezo element type surface stress sensor.

[Sensor manufacturing method]
The method for manufacturing the sensor of this embodiment is not particularly limited, but it can be manufactured by various methods for forming a receptor on the sensor body. The receptor in this embodiment is manufactured by, for example, dispersing an organic-inorganic hybrid in an organic solvent to prepare a coating liquid, and applying the coating liquid onto the sensor body. An inkjet device can be suitably used when applying the coating liquid onto the sensor chip. According to an inkjet device, droplets of a coating liquid are ejected, the droplets are applied onto a sensor, and a receptor is formed. An example of forming a receptor on a chip is shown in FIG. The sensor 1 is configured to have a chip 3 corresponding to the sensor body and a receptor 2 formed on the surface thereof, and in the example shown in FIG. 1, this configuration is provided at four locations. .

The method for coating the surface of the sensor body (for example, the MSS sensor body) with the organic-inorganic hybrid is not particularly limited, and examples thereof include dip coating, spray coating, spin coating, inkjet spotting, casting, doctor blade, etc. Examples include coating methods.

In order to coat a membrane with a diameter of 300 μm, an inkjet method or a microjet method is preferable, and a microjet method is more preferable from the viewpoint of productivity.

The receptor in this embodiment can be manufactured, for example, by dispersing an organic-inorganic hybrid in an organic solvent and applying the dispersion onto a chip of an MSS sensor. The organic-inorganic hybrid is dispersed in an organic solvent at a concentration of 0.1 g/L to 50 g/L to form a coating liquid. The concentration of the organic-inorganic hybrid is preferably 0.5 to 50 g/L from the viewpoint of productivity, and more preferably 0.5 to 15 g/L from the viewpoint of suppressing nozzle clogging.

The organic solvent for dispersing the organic-inorganic hybrid may be any dispersible solvent, preferably one with a boiling point of 80°C to 250°C, and from the viewpoint of suppressing a decrease in productivity due to nozzle clogging, one with a boiling point of 100°C A boiling point of 100° C. to 250° C. is preferable, and a boiling point of 100° C. to 200° C. is more preferable from the viewpoint of speeding up the drying time and increasing productivity.

Examples of the organic solvent include, but are not limited to, alcohol solvents, ester solvents, ketone solvents, ether solvents, aliphatic hydrocarbon solvents, aromatic hydrocarbon solvents, amide solvents, and the like.

Examples of alcohol solvents include, but are not limited to, monohydric alcohols such as methyl alcohol, ethyl alcohol, propyl alcohol, and butyl alcohol; polyhydric alcohols such as ethylene glycol, diethylene glycol, propylene glycol, glycerin, trimethylolpropane, and hexanetriol. Alcohol; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol mono Examples include monoethers of polyhydric alcohols such as ethyl ether, propylene glycol monopropyl ether, and propylene glycol monobutyl ether.

Examples of the ester solvent include methyl acetate, ethyl acetate, butyl acetate, and γ-butyrolactone.

Examples of the ketone solvent include, but are not limited to, acetone, methyl ethyl ketone, methyl isoamyl ketone, and the like.

Ether solvents include, but are not limited to, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, propylene glycol dimethyl ether, propylene glycol diethyl ether, propylene glycol dibutyl ether, diethylene glycol dimethyl ether, Examples include polyhydric alcohol ethers in which all of the hydroxyl groups of a polyhydric alcohol are alkyl etherified, such as diethylene glycol methyl ethyl ether and diethylene glycol diethyl ether; tetrahydrofuran; 1,4-dioxane; anisole; and the like.

Examples of the aliphatic hydrocarbon solvent include, but are not limited to, hexane, heptane, octane, nonane, decane, and the like.

Examples of the aromatic hydrocarbon solvent include, but are not limited to, benzene, toluene, xylene, and the like.

Examples of the amide solvent include, but are not limited to, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and the like.

These organic solvents may be used alone or in combination of two or more. Among these organic solvents, N,N-dimethylformamide and propylene glycol monomethyl ether are preferred because of their excellent safety and solubility.

The receptor in this embodiment may contain additives such as arbitrary particles, ionic compounds, resins, and low-molecular compounds in addition to the organic-inorganic hybrid. A sensor having a receptor containing the additive can be obtained by, for example, adding the additive to a coating liquid and applying it to the surface of the sensor body.

Hereinafter, the present embodiment will be specifically described with reference to Examples and Comparative Examples, but the present embodiment is not limited thereto.

Various physical properties of the MSS sensors of each Example and Comparative Example were evaluated according to (1) to (6) below.

(1) Measurement of porosity of receptor After fixing the sample whose cross section was formed by dicing on a processing table, it was processed using FIB Milling described below and observed using a scanning electron microscope (SEM). The SEM observation conditions were as follows.
(Processing conditions FIB Milling)
Equipment Helios 650
Rough processing carried out after forming a protective film with W Acceleration voltage 30kV
Current value changed in order of 9.4nA, 2.4nA, 0.7nA (finishing)
Acceleration voltage 30 kV
Current value 0.24nA
(SEM observation conditions)
Equipment Helios 650 (manufactured by ThermoFisher SCIENTIFIC)
Acceleration voltage 2kV, 0.1 or 0.2nA
Observation image Backscattered electron image (composition image)
Incline 52°
The voids existing in the organic-inorganic hybrid were extracted from the image obtained by cross-sectional SEM observation. For extraction, binarization processing was performed using image analysis software, taking advantage of the fact that in the acquired image, the area around the gap has bright contrast due to the edge effect, and the gap itself has dark contrast. At that time, a binarization process was performed in which the structural layer was made white and the voids, substrate, and background were made black. For parts that could not be tracked by the binarization process, manual discrimination was performed to supplement them. In the extracted image of the voids obtained, the ratio of the area of the portion corresponding to the void to the area of the structural layer and the portion corresponding to the void was calculated as the porosity of the receptor layer. The above operation was performed for three visual fields, and the number average value was taken as the porosity.

(2) Measurement of volume fraction of filler Among the cross-sectional images obtained in (1), the ratio of the area of the filler portion to the other area was calculated as the volume fraction of the filler. The above operation was performed for three visual fields, and the number average value was taken as the volume fraction.

(3) Thermogravimetric loss rate (determination of organic components)
A powder sample of the receptor scraped from the MSS sensor was dried in air at 100° C. and then allowed to come to room temperature before being accurately weighed. Thereafter, organic components were removed by heating in the air from 150° C. to 1000° C. at a rate of 10° C./min using TGA, and the thermogravimetric reduction rate was determined. Since only the organic groups were decomposed by heating and the SiO _3/2 portion remained as silica, the thermal weight reduction rate was taken as the organic component amount (% by weight).

(4) Physical/chemical stability (1st time)
Water saturated steam was used as the analyte. Signal intensity was measured under dry conditions at 25° C. with water saturated steam purged with 6 sccm nitrogen for 10 minutes (total flow rate set at 30 sccm).
(2nd time)
Ethanol was used as the analyte. Signal intensity was measured under dry conditions at 25° C. with an ethanol headspace gas purged with 6 sccm nitrogen for 10 minutes (total flow rate set at 30 sccm).
(3rd time)
Toluene was used as the analyte. Signal intensity was measured under dry conditions at 25° C. with a toluene headspace gas purged with 6 sccm of nitrogen for 10 minutes (total flow rate set at 30 sccm).
After each measurement, changes in the film shape were observed using an optical microscope and evaluated as follows.
A: No change was observed even after the third time.
B: After the second time, no change was observed, but after the third time, a clear change in the shape of the membrane was observed under a microscope with a magnification of 200 times.

C: A clear change in the shape of the membrane was observed under a microscope with a magnification of 200 times after the second time.

(5) Aldehyde selectivity 250 ppm of the following nine gases (ethanol, acetone, ethyl acetate, acetaldehyde, ethylene, toluene, trimethylamine, dimethyl sulfide, dimethyl disulfide) was measured for 1 hour at 25° C. under dry nitrogen. Each sensitivity is divided by the sensitivity of acetaldehyde, and when the sensitivity of acetaldehyde is taken as 1, the maximum value of each sensitivity relative value is 0.75 or less, and the maximum value is 0.76 or more and 0.85 or less. Those that did not fit were labeled as B, and those that did not fit into any of the categories were labeled as C.

(6) Humidity resistance The measurement was carried out at 25° C. and 250 ppm of acetaldehyde for 1 hour. 100 x (“Intensity of signal measured under dry condition” - “Intensity of signal measured under 50 RT%”)/(“Intensity of signal measured under dry condition” is the attenuation rate (%), and its A value of 20% or less was designated as S, a value of 21% to 40% was designated as A, a value of 41% or more but less than 50% was designated as B, and a value of 51% or more was designated as C.

<Example 1>
In a separable flask, add 10 g of a 2-propanol dispersion of linear colloidal silica IPA-ST-UP (Nissan Chemical Products), 18 g of water, 2 g of 28% ammonia water, 80 g of 2-propanol, and 3-(2-imidazolinepropyl) trichloride. 8.3 g of ethoxysilane was added and reacted at 80° C. for 3 hours. After air-cooling the reaction solution, the precipitate was isolated by centrifuging at 6000 rpm for 10 minutes. After thoroughly washing the sample with ethanol, it was dissolved in N,N dimethylformamide to a concentration of 10 mg/mL to obtain a coating solution. Samples were partially dried at 80° C. under vacuum and the thermogravimetric loss was measured. An MSS sensor with a receptor was obtained by applying a portion of the coating liquid onto the surface of the MSS sensor body placed on a 40° C. hot plate using an inkjet device. In the above coating, first, two 300 pL droplets were applied in succession (600 pL), and the same operation was repeated after 1 second for drying (30 times in total). That is, 18,000 pL of coating liquid was used. The typical appearance of the MSS sensor was similar to that shown in FIG.
Next, the cross-sectional SEM image of the MSS sensor according to Example 1 was observed, and the porosity and volume fraction were calculated as described in (1) and (2) above based on the cross-sectional SEM image.
The physicochemical stability was evaluated by the method (4). No change was observed after the second observation using an optical microscope at a magnification of 200 times, but a clear change in the shape of the film was observed under the microscope after the third observation, so it was designated as B.
The aldehyde selectivity evaluated as in (5) had a maximum relative value of 0.78 and was designated as B. The humidity resistance evaluated as in (6) was 42% and was rated B.
In addition, the following Examples and Comparative Examples were also evaluated in the same manner as described above. The results of each evaluation are also shown in Table 1.

<Example 2>
In a 500 mL separable flask, add 7.2 g of phenyltrimethoxysilane and 6.6 g of 3-(2-imidazolinepropyl)triethoxysilane to 24 g of 2-propanol in 36 g of water, 4 g of 28% ammonia water, and 106.4 g of 2-propanol. A solution dissolved in was added and reacted at 80°C for 3 hours. After cooling the reaction solution in air, the precipitate was collected and isolated by filtration. After thoroughly washing the sample with ethanol and drying it, it was dissolved in DMF to a concentration of 10 g/mL. A solution of 2-propanol dispersion IPA-ST-UP (Nissan Chemical Products) adjusted to 10 mg/mL with DMF and the above solution were mixed at a ratio of 6:4 to obtain a coating solution. The subsequent evaluations were based on Example 1.

<Example 3>
The procedure of Example 2 was followed except that IPA-ST-UP (Nissan Chemical Products) in Example 2 was changed to IPA-ST-ZL (Nissan Chemical Products).

<Example 4>
The procedure of Example 1 was followed except that 27.1 g of 3-(2-imidazolinepropyl)triethoxysilane in Example 1 was changed to 6.2 g of 3-N,N dimethylaminopropyltrimethoxysilane.

<Example 5>
In a 500 mL separable flask, add 7.2 g of phenyltrimethoxysilane and 5.0 g of 3-N,N dimethylaminopropyltrimethoxysilane to 36 g of water, 4 g of 28% ammonia water, and 106.4 g of 2-propanol. A solution dissolved in 24 g was added and reacted at 80° C. for 3 hours. After cooling the reaction solution in air, the precipitate was collected and isolated by filtration. After thoroughly washing the sample with ethanol and drying it, it was dissolved in DMF to a concentration of 10 g/mL to obtain a coating solution. The subsequent evaluations were based on Example 1.

<Example 6>
The procedure of Example 2 was followed except that 6.6 g of 3-(2-imidazolinepropyl)triethoxysilane in Example 2 was changed to 5.0 g of 3-N,N dimethylaminopropyltrimethoxysilane.

<Example 7>
The procedure of Example 6 was followed except that IPA-ST-UP (Nissan Chemical Products) in Example 6 was changed to IPA-ST-ZL (Nissan Chemical Products).

<Example 8>
The procedure of Example 7 was followed except that instead of mixing at a ratio of 6:4 as in Example 7 to obtain a coating liquid, a ratio of 19:1 was mixed to obtain a coating liquid.

<Example 9>
The procedure of Example 7 was followed except that instead of mixing at a ratio of 6:4 as in Example 7 to obtain a coating liquid, the coating liquid was obtained by mixing at a ratio of 1:4.

<Example 10>
6.6 g of 3-(2-imidazolinepropyl)triethoxysilane in Example 2 was changed to 6.4 g of 3-(2-aminopropylethylamino)propyltriethoxysilane, and IPA-ST-UP (Nissan Chemical Products) was converted into IPA. The procedure of Example 2 was followed except that -ST-ZL (Nissan Chemical Products) was used.

<Example 11>
7.2 g of phenyltrimethoxysilane of Example 2 and 6.6 g of 3-(2-imidazolinepropyl)triethoxysilane were changed to 12.8 g of 4-aminophenyltrimethoxysilane, and IPA-ST-UP (Nissan Chemical Products) was prepared. The procedure of Example 2 was followed except that IPA-ST-ZL (Nissan Chemical Products) was used.

<Example 12>
27.1 g of 3-(2-imidazolinepropyl)triethoxysilane in Example 2 was changed to 5.1 g of 4-aminophenyltrimethoxysilane, and IPA-ST-UP (Nissan Chemical) was changed to IPA-ST-ZL (Nissan Chemical). Example 2 was followed except that the product was changed to (product).

<Example 13>
27.1 g of 3-(2-imidazolinepropyl)triethoxysilane in Example 2 was changed to 6.4 g of 3-ureidopropyltriethoxysilane, and IPA-ST-UP (Nissan Chemical) was changed to IPA-ST-ZL (Nissan Chemical). Example 2 was followed except that the product was changed to (product).

<Example 14>
7.2 g of phenyltrimethoxysilane and 6.6 g of 3-(2-imidazolinepropyl)triethoxysilane in Example 2 were changed to 14.5 g of 3-pyridinetriethoxysilane, and IPA-ST-UP (Nissan Chemical Products) was added. The procedure of Example 2 was followed except that IPA-ST-ZL (Nissan Chemical Products) was used.

<Example 15>
27.1 g of 3-(2-imidazolinepropyl)triethoxysilane in Example 2 was changed to 5.8 g of 3-pyridinetriethoxysilane, and IPA-ST-UP (Nissan Chemical Products) was changed to IPA-ST-ZL (Nissan Chemical Products). ) The procedure was the same as in Example 2 except that

<Example 16>
27.1 g of 3-(2-imidazolinepropyl)triethoxysilane in Example 2 was changed to 5.3 g of 3-acetamidopropyltrimethoxysilane, and IPA-ST-UP (Nissan Chemical) was changed to IPA-ST-ZL (Nissan Chemical). Example 2 was followed except that the product was changed to (product).

<Example 17>
27.1 g of 3-(2-imidazolinepropyl)triethoxysilane in Example 2 was changed to 6.0 g of 3-piperidinopropyltrimethoxysilane, and IPA-ST-UP (Nissan Chemical Products) was changed to IPA-ST-ZL ( The procedure of Example 2 was followed except that the material was changed to (Nissan Chemical Products).

<Example 18>
27.1 g of 3-(2-imidazolinepropyl)triethoxysilane in Example 2 was changed to 6.0 g of 3-piperazinopropyltrimethoxysilane, and IPA-ST-UP (Nissan Chemical Products) was changed to IPA-ST-ZL ( The procedure of Example 2 was followed except that the material was changed to (Nissan Chemical Products).

<Example 19>
27.1 g of 3-(2-imidazolinepropyl)triethoxysilane in Example 2 was changed to 6.3 g of 3-(cyclohexylamino)propyltrimethoxysilane, and IPA-ST-UP (Nissan Chemical Products) was changed to IPA-ST-ZL. (Nissan Chemical Products) The same procedure was followed as in Example 2 except that the material was changed to (Nissan Chemical Products).

<Example 20>
27.1 g of 3-(2-imidazolinepropyl)triethoxysilane in Example 2 was changed to 6.1 g of 3-phenylaminopropyltrimethoxysilane, and IPA-ST-UP (Nissan Chemical Products) was changed to IPA-ST-ZL (Nissan Chemical Products). The procedure of Example 2 was followed except that the chemical product was changed to (chemical product).

<Comparative example 1>
7.2 g of phenyltrimethoxysilane and 6.6 g of 3-(2-imidazolinepropyl)triethoxysilane in Example 2 were changed to 11.9 g of phenyltrimethoxysilane, and IPA-ST-UP (Nissan Chemical Products) was added to IPA. The procedure of Example 2 was followed except that -ST-ZL (Nissan Chemical Products) was used.

<Comparative example 2>
A solution of 11.9 g of phenyltrimethoxysilane dissolved in 24 g of 2-propanol was added to 36 g of water, 4 g of 28% aqueous ammonia, and 106.4 g of 2-propanol in a 500 mL separable flask, and the mixture was reacted at 80° C. for 3 hours. After cooling the reaction solution in air, the precipitate was collected and isolated by filtration. After thoroughly washing the sample with ethanol and drying it, it was dissolved in DMF to a concentration of 10 g/mL to obtain a coating solution. The subsequent evaluations were based on Example 1.

<Comparative example 3>
Silica titania particles (granular) were synthesized according to the method described in WO2016/121155. It was synthesized by cohydrolysis and condensation polymerization of aminopropyltrimethoxysilane and titanium tetraisopropoxide (TTIP) in an ammonia-based aqueous isopropanol (IPA) solution in which octadecylamine (ODA) was dissolved. The above synthesis reaction was carried out using a Teflon (registered trademark) microreactor having a micrometer-sized Y-shaped flow path. There are four precursor solutions: solution 1: aminopropyltrimethoxysilane/IPA, solution 2: H ₂ O/IPA/ammonia, solution 3: TTIP/IPA, and solution 4: H ₂ O/IPA. The volumes were made to be the same up to 4. The precursor solution was simultaneously delivered at a constant rate using a syringe pump. Solution 1 and solution 2, and solution 3 and solution 4 were mixed in parallel microreactors, and the discharged liquid from both reactors was further mixed in another microreactor to form one reaction solution. The reaction solution was discharged into a separately prepared precursor solution 5: ODA/H ₂ O/IPA, and stirred at a constant speed until the discharge was completed. Thereafter, it was allowed to stand at room temperature to obtain a nanoparticle (NH ₂ -STNP) dispersion. Since the structure represented by RSiO _3/2 was confirmed in these nanoparticles, they were treated as an organic-inorganic hybrid. After cooling the reaction solution in air, the precipitate was isolated by centrifuging at 6000 rpm for 10 minutes. After thoroughly washing the sample with ethanol, it was dissolved in N,N-dimethylformamide to a concentration of 1 g/mL to obtain a coating solution. An MSS sensor with a receptor was obtained by applying 300 drops of the coating liquid at a volume of 300 pL per drop onto the surface of the MSS sensor body placed on a hot plate at 80 °C. Ta. Since cracks and peeling were observed in the receptor layer after coating, the physical and chemical stability was rated C. Since the aldehyde responsiveness was 4.6, it was designated as C. Since the humidity resistance was 0.94, it was designated as C.

The results of the above measurements (1) to (6) for each Example/Comparative Example are shown in Tables 1 to 3 below.

The sensor of the present invention can be used as an olfactory sensor for breath testing and odor control in hotels, automobiles, and factories.

1 sensor 2 receptor (sensitive membrane)
3 Chip (sensor body)

Claims (13)

The following formula (1)
RSiO _3/2 (1)
(In formula (1), R represents an organic group containing at least one nitrogen atom)
A sensor comprising an organic-inorganic hybrid having a structure represented by the above structure, a spherical filler, and a receptor having a porosity of 3% or less. The sensor according to claim 1, wherein the R has an amino group or a heterocycle containing a nitrogen atom. The sensor according to claim 1 or 2, wherein the R has a tertiary amino group. The sensor according to any one of claims 1 to 3, wherein the R has at least one aromatic ring. The sensor according to claim 4, wherein the aromatic ring is directly bonded to a Si atom. The sensor according to any one of claims 1 to 5, wherein the R has a copolymerized structure of an aromatic ring and a non-aromatic ring. The sensor according to any one of claims 1 to 6, wherein the R has an alkylaminoalkyl group. The sensor according to any one of claims 1 to 7 , wherein the filler is an inorganic filler. A sensor according to any one of claims 1 to 8 , wherein the filler is a metal oxide. A sensor according to any one of claims 1 to 8 , wherein the filler is silica. The sensor according to any one of claims 1 to 10 , comprising the filler in a volume fraction of 1 to 70%. The sensor according to any one of claims 1 to 11 , comprising the filler in a volume fraction of 3 to 40%. The sensor according to any one of claims 1 to 12 , wherein the thermogravimetric loss rate of the receptor is 65% by weight or less.