KR101792363B1 - Textile colorimetric sensors and member with dye anchored one dimensional polymer nanofibers for decting hydrogen sulfide gas and manufacturing method thereof - Google Patents

Textile colorimetric sensors and member with dye anchored one dimensional polymer nanofibers for decting hydrogen sulfide gas and manufacturing method thereof Download PDF

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KR101792363B1
KR101792363B1 KR1020150181211A KR20150181211A KR101792363B1 KR 101792363 B1 KR101792363 B1 KR 101792363B1 KR 1020150181211 A KR1020150181211 A KR 1020150181211A KR 20150181211 A KR20150181211 A KR 20150181211A KR 101792363 B1 KR101792363 B1 KR 101792363B1
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dye
polymer
gas
acetate
powder
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김일두
구원태
차준회
금동기
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한국과학기술원
동우 화인켐 주식회사
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/75—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated
    • G01N21/77—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator
    • G01N21/78—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour
    • G01N21/783—Systems in which material is subjected to a chemical reaction, the progress or the result of the reaction being investigated by observing the effect on a chemical indicator producing a change of colour for analysing gases
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
    • C09B67/00—Influencing the physical, e.g. the dyeing or printing properties of dyestuffs without chemical reactions, e.g. by treating with solvents grinding or grinding assistants, coating of pigments or dyes; Process features in the making of dyestuff preparations; Dyestuff preparations of a special physical nature, e.g. tablets, films
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N31/00—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods
    • G01N31/22—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators
    • G01N31/223—Investigating or analysing non-biological materials by the use of the chemical methods specified in the subgroup; Apparatus specially adapted for such methods using chemical indicators for investigating presence of specific gases or aerosols
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y15/00—Nanotechnology for interacting, sensing or actuating, e.g. quantum dots as markers in protein assays or molecular motors
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures

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Abstract

A lead (II) acetate (Pb (CH 3 COO) 2 ) powder, which is a dye material which is brownish in color and reacts with hydrogen sulfide gas, is uniformly bonded to the inside and the outside of a one- (II) acetate / polymer composite color change nanofiber sensor and a manufacturing method thereof. Specifically, the dye powder is pulverized to a nanometer or submicron size through a high energy ball milling process, and an electric spinning solution in which dye powders are uniformly dispersed is prepared by mixing fine dye powders with a polymer and a solvent. And the polymer nanofibers obtained by spinning are bound to a dye powder. This one-dimensional nanostructure provides more pores so that the sensing gas can diffuse into the structure containing the dye powder, so that the reaction site limited to the surface can also be expressed in the inside of the membrane, Can be significantly increased. The present invention is capable of mass-producing color-changing nanofiber sensors using electrospinning that can be manufactured at relatively low cost and provides a surface area and porosity higher than that of the lead (II) acetate material of the conventional test paper for the detection of hydrogen sulfide, Even if exposed to hydrogen sulfide at a concentration lower than 1 ppm, which could not be detected by the color change sensor, embolization can occur within a few tens of seconds, so that it can be used as a bad breath diagnostic color change gas sensor through exhalation gas.

Description

TECHNICAL FIELD [0001] The present invention relates to a member for fabric type color change gas sensor using a one-dimensional polymer nanofiber with dye for hydrogen sulfide gas detection, a color change gas sensor, and a method of manufacturing the same. BACKGROUND ART [0002] AND MANUFACTURING METHOD THEREOF}

The present invention relates to a member for a fabric type color change gas sensor in which a dye exhibiting a color change response to a specific gas is bound to a one-dimensional polymer nanofiber, a gas sensor, and a manufacturing method thereof. Specifically, dye-polymer composite nanofibers containing both polymer and dye are synthesized by electrospinning, so that the dye particles uniformly bind to the inside and the outside of the nanofiber, and the porous structure having high surface area and gas diffusion of the nanofiber And a method of manufacturing the same.

Gas sensors are used throughout the society. In industry, hazardous environment gas alarm is used to detect leakage of harmful gas early to prevent big accidents and personal injury. It is used as air pollution meter or indoor air quality meter close to real life. It provides a pleasant environment through monitoring the overall air quality of the space.

As gas sensors, there are various gas sensors depending on the gas sensing operation method such as gas chromatography, resistance change type gas sensor and color change sensor. In gas chromatography, vaporization occurs as the sample is injected into the injection port, and the gas phase substance is separated by the columns in the gas chromatography. The separated gaseous compound component is detected by the detector and displays an electrical signal proportional to the detected amount through the connected monitor. Gas chromatography is capable of highly accurate gas quantitative analysis when compared to other gas sensors, but it is not suitable for portable equipment because of its high cost and large equipment size. In addition, since the sample must be injected and simultaneously vaporized, the sample must have volatile characteristics. Therefore, there is a disadvantage that the molecular weight of the analytical sample is limited and the substance which is not stable to heat is difficult to analyze.

A resistance-change type gas sensor based on a metal oxide semiconductor detects an analyte of interest using a change in electrical resistance caused by a process of adsorbing and desorbing a specific gas on a surface of a metal oxide semiconductor. Gas sensors based on metal oxide semiconductors can quantitatively detect specific gases by analyzing resistance ratios in specific gases versus resistance in air. In the case of such a resistance change type gas sensor, the sensor system configuration is simple, and the size is small, which is advantageous in that it is easy to carry. However, much research is still being done because it is far behind gas chromatography in sensitivity and selectivity. In addition to gas sensors based on gas chromatography and metal oxide semiconductors, studies on colorimetric sensors capable of observing color change in response to a specific gas have also been actively conducted. The color change gas sensor changes the absorption wavelength of the visible light due to the influence of the material used as the dye in the gas sensor and the bandgap that is the electrical property, And an embolus can be judged by the naked eye. Or a colored product different from the color of the raw material is formed through the chemical reaction caused by the contact of the specific gas with the dye, so that the presence or absence of the analysis gas can be determined. A gas sensor using a color change material is advantageous in that it does not need additional circuit design and measurement equipment as compared to a metal oxide semiconductor gas sensor because it can distinguish an embolus visually. In addition, it is easy to carry around in test form, so you can monitor and detect gas in real time regardless of time and place. However, gas sensitivity characteristics and selectivity are far behind those of gas chromatography and resistance change type gas sensors.

Among the various fields covered by the gas sensor, a research on a healthcare expiratory sensor capable of diagnosing a specific disease at an early stage by detecting a bio-indicator gas has attracted a great deal of attention. Volatile organic compounds produced by the reaction of cells inside the body are transported through the blood to the lungs and released from the mouth through gas exchange. Therefore, there are various biological surface gases such as ammonia, nitrogen monoxide, acetone, toluene, pentane, and hydrogen sulfide in the exhalation, and these gases are reported as biomarkers for kidney disease, asthma, diabetes, lung cancer, . Because there are hundreds of thousands of mixed gases in the expiration, it is necessary to be able to selectively detect a specific biomass surface gas. In addition, since the biomass gas contained in the exhalation is emitted at a very low concentration ranging from 10 ppb (parts per billion) to 10 ppm (part per million), it is necessary to detect a high concentration Development of a gas sensor having sensitivity is required.

In order to develop a gas sensor with high sensitivity characteristics, various gas sensing materials based on various nanostructures have been developed recently. Since the color change gas sensor generates embolization due to the surface reaction between the surface of the dye material and the detection gas, higher sensitivity characteristics can be expected as the surface area of the dye material reactive with the detection gas molecules is wider. From this point of view, nanostructure sensing materials including nanoparticles, nanofibers, and nanotube structures can have excellent gas sensing characteristics because they have a relatively large area of reacting with gases compared with thick films, Can provide rapid reaction characteristics because they provide a porous structure that can penetrate sufficiently quickly into the sensing material.

Lead (II) acetate (Pb (CH 3 COO) 2 ) is known as a dye capable of selectively sensing hydrogen sulfide gas. Already in the market there is a film type product for detecting the leakage of hydrogen sulfide gas in the industrial field. However, since the detection limit is only about 5 ppm, it has not been possible to detect a trace amount of hydrogen sulfide gas at 1 ppm or less. Hydrogen sulfide is a biomarker of halitosis, which contains hydrogen sulfide at a concentration of 50 ppb to 80 ppb for excretion of normal persons, whereas it ranges from 1 ppm to 2 ppm for exhalation of halitosis patients. Acetic acid in film form, however, can not detect low levels of hydrogen sulphide present in exhalation due to its sensitivity limit.

In order to produce a high-sensitivity color-change sensor, it is necessary to develop a color-change sensor material having a large surface area so as to provide a large number of reaction regions that can meet the gas of the analysis species. In the case of thick film color change sensors, most of the reactions take place on the surface of the film, and due to the absence of pores, the gas molecules do not diffuse into the sensing material, resulting in a relatively limited response. Therefore, it is also necessary to develop a color change sensor material having a porous structure in which gas molecules can diffuse into the sensing material. In addition, when the color-changing dyes bind to the interior of the nanostructure, the reaction gas can not reach the analyte due to the limited diffusion of the reaction gas into the nanostructure forming material. Therefore, it is also important to distribute the dye on the surface of the nanostructure so that it meets the reaction gas at the surface of the nanostructure and causes embolization.

It is an object of the present invention to provide a method of fabricating a color change sensor for detecting a hydrogen sulfide gas by easily synthesizing a nanostructure that provides a reaction region in which a dye exhibiting a color change response to a specific gas can meet with the same gas.

The present invention for preparing a dye material having a nano-fiber-shaped in one dimension by using a high energy ball mill grinding nanosized powder with electrospinning technique rough process, Lead (II) an appropriate amount of acetate (Pb (CH 3 COO ) 2 ) and a polymer are mixed to prepare an electrospinning solution, and electrospinning is performed on the nonwoven fabric to prepare a color change sensor for sensing hydrogen sulfide gas in the form of a membrane.

Disclosure of Invention Technical Problem [8] The present invention provides a method of synthesizing a composite nanofiber comprising a polymer and a dye by using an electrospinning method, wherein the dye particles are uniformly formed on the inside and the outside of the nanofiber, And an object thereof is to provide a color change gas sensor capable of detecting an extremely small amount of analytical gas by using the gas sensor and its manufacturing method.

In order to solve the above problem, in the present invention, a high energy ball milling process is carried out to obtain a nano-sized dye (lead (II) acetate (Pb (CH 3 COO) 2 ), and a nano- The present invention provides a color change gas sensor having a large surface area and a method of manufacturing a member for a gas sensor using the same, wherein the dye powder is uniformly bound to the inside and the outside of the nanofiber using an electrospinning method. The present invention provides a method for manufacturing a sensor material and a gas sensor member using the same, which comprises the steps of (a) subjecting a dye material, Lead (II) acetate (Pb (CH 3 COO) 2 ) (B) dissolving the nano-sized dye powder and the polymer in a solvent to prepare an electrospinning solution; (c) irradiating the electrospinning solution with a polymer and a dye using an electrospinning method; Of Lead (II) binding to nanofibers complexing and dye material to each other acetate (Pb (CH 3 COO) 2) the step of forming the nanofibers uniformly remain in the inner and the surface of the nanofibers; (d) the electrical (II) acetate composite color change nanofiber sensor including a step of forming a polymer / lead (II) acetate composite nanofiber membrane by direct spinning of a composite nanofiber formed by spinning onto a nonwoven fabric .

When the lead (II) acetate (Pb (CH 3 COO) 2 ) is purchased from the market in the step (a), the powder size is large enough to be 100 μm or more. Therefore, in order to bond the nanofibers to the nanofibers through electrospinning, the size of the dye powder should be less than 1 μm. Since the diameter of polymer nanofibers to be produced is usually in the range of 100 nm to 1000 nm by using electrospinning, it is preferable that the dye powder having a size smaller than the diameter of the nanofibers is bound to the nanofibers. Therefore, in order to obtain such nano-size powder, a high-energy ball milling process may be carried out to obtain powders smaller than the thickness of the nanofiber, and the pulverized dyes may remain in the outer and inner portions of the fiber during electrospinning. The nano-sized dye powders obtained through the high energy ball milling process can be obtained in an average diameter of 50 nm to 2 μm.

In the step (b), an electrospun solution is prepared by mixing a nano-sized dye powder obtained through a high energy ball milling process with a polymer. Specifically, the polymer may be cellulose, cellulose acetate butyrate (PMA), polyvinyl acetate (PVAc), polymethyl methacrylate (PMMA), polyacrylic copolymer, polyvinyl acetate copolymer, polyvinyl acetate, and the like. Polyvinylpyrrolidone (PVP), polystyrene copolymer, polyethylene oxide (PEO), polypropylene (PVP), polyvinylpyrrolidone (PVP) (PPO), polyacrylonitrile (PAN), polycarbonate (PC), polyurethane, polyurethane copolymer, Examples thereof include cellulose acetate, polyvinyl chloride (PVC), polycaprolactone, polyvinyl fluoride, polyaniline (PANI), polyvinylidene fluoride copolymer, polyimide, Polyvinyl alcohol (PVA), polycarbonate (PC), polyvinylidene fluoride (PVDF), polyethylene (PE), polyethylene (PE) , Polyethylene terephthalate (PET), and polypropylene (PP). In addition, the nano-sized powder prepared in the step (a) may be added to the electrospinning solution to prepare an electrospinning solution. When preparing an electrospinning solution, the weight ratio of the nano-sized dye powder can be variously adjusted in the range of 0.5 wt% to 90 wt% with respect to the polymer constituting the nanofiber composite. In electrospinning solutions, the solvent is selected from the group consisting of dimethylformamide (DMF), ethanol, acetone, tetrahydrofuran, ethylene glycol (EG), toluene, dimethylacetamide (II) acetate (Pb (CH 3 COO) 2 ), which is the above nanofiber composite, is prepared by using any one or two or more kinds of solvents selected from dimethylsulfoxide (DMAc, Dimethylacetamide) and dimethylsulfoxide (DMSO) wt% to 99 wt%, based on the total weight of the composition.

The step (c) is a step of synthesizing a polymer / lead (II) acetate composite nanofiber using an electrospinning technique, wherein the nano-sized powder synthesized in the step (a) And is functionalized to nanofibers having a large surface area and high porosity. When the binding strength of the dye is weak, it is important that the dye powder bind strongly to the inside and outside of the matrix of the polymeric nanofibers, since the dye powder may be separated from the fibers before the color change sensor is measured. When the electrospinning method is used, the dye powder dispersed in the polymer is electrospun together to form the dye powder-polymer composite fiber, so that the binding strength is very high.

In step (d), the composite nanofibers formed by the electrospinning method are directly spun on the nonwoven fabric to form a polymer / lead (II) acetate composite nanofiber membrane. It is easier to manufacture polymer / lead (II) acetate complex color change nanofiber sensor because it is easy to cut into square paper form by direct irradiation on nonwoven fabric. Lead (II) acetate composite nanofibers have an individual diameter ranging from 50 nm to 10 μm. Lead (II) acetate complex (Pb (CH 3 COO) 2 ) In nanofibers, H 2 S gas reacts with lead (II) acetate (Pb (CH 3 COO) 2 ) to change the color as PbS phase is formed. Depending on the surrounding conditions, the embryo is dark brown in the dry environment, while it changes to brown in the wet condition. The diameter of the nanofibers may more preferably be in the range of 100 nm to 1000 nm in diameter. Since the reaction site between the gas and the dye powder exposed on the surface of the nanofiber increases as the maximum diameter of the nanofiber decreases, it is preferable that the diameter of the nanofiber is about 300 nm on average.

The thickness of the composite nanofiber membrane used for the dye powder-polymer nanofiber composite color-change sensor obtained on the nonwoven fabric can be set in the range of 5 μm to 100 μm.

According to the present invention, lead (II) acetate (Pb (CH 3 COO) 2 ) is finely pulverized through a high energy ball milling process to obtain a dye powder having a size of several tens to several hundred nanometers, preferably 20 nm to 500 nm Lead (II) acetate, which reacts selectively with a very small amount of hydrogen sulphide by synthesizing composite nanofiber sensing material in which nano-sized dyes are uniformly bound to the inside and outside of a one-dimensional nanofiber by dispersing them together in an electric spinning solution A composite color change nanofiber gas sensor can be provided.

Polymer / Lead (II) acetate composite color change nanofibers prepared using electrospinning technology provide higher surface area and porosity than conventional lead (II) acetate materials for hydrogen sulfide detection test paper. Therefore, even when exposed to hydrogen sulfide at a concentration lower than 1 ppm, embolization occurs within tens of seconds, and thus it can be used as a color change gas sensor capable of detecting bad breath and detecting harmful hydrogen sulfide gas at high sensitivity / high speed.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
FIG. 1 is a schematic view of a member for a polymer / lead (II) acetate complex color change nanofiber sensor in which a nano-sized powder according to an embodiment of the present invention is uniformly bound to the inside and the surface of a nanofiber.
FIG. 2 shows a manufacturing process of a polymer / lead (II) acetate complex color-changing nanofiber sensor in which a nano-sized powder is uniformly bound to the inside and the surface of a nanofiber using electrospinning according to an embodiment of the present invention. It is a picture.
FIG. 3 is a flow chart of a method of manufacturing a color change gas sensor using a polymer / lead (II) acetate complex color change nanofiber structure in which nanosized powders are uniformly bound to the inside and the surface of a nanofiber according to an embodiment of the present invention to be.
4 is a scanning electron microscope (SEM) image of the pulverized dye powder through the high energy ball milling process according to Example 1 of the present invention.
5 is a scanning electron micrograph of a dye powder-polymer composite nanofiber synthesized by electrospinning according to Example 1 of the present invention.
6 is a scanning electron microscope (SEM) image of a pure dye powder not subjected to an electrospinning process according to Comparative Example 1. FIG.
7 is a scanning electron micrograph of the dye powder-polymer composite nanofiber obtained by electrospinning with a dye powder not subjected to a high energy ball milling process according to Comparative Example 2. FIG.
8 is a graph showing the relationship between the concentration of hydrogen sulfide gas and the amount of hydrogen sulfide gas obtained by directly exposing the hydrogen sulfide gas to 5, 4, 3, 2 and 1 ppm in a dry environment free from moisture at room temperature according to Example 1, Comparative Example 1 and Comparative Example 2 The degree of color change of the fiber sensor is shown.
9 is a graph showing the relationship between the concentration of the hydrogen sulfide gas at 5, 4, 3, 2, and 1 ppm, which is the relative humidity (80% RH), similar to the humidity of dry humidified hydrogen sulfide gas And the degree of color change directly exposed for 1 minute.
10 is a graph showing the relationship between the concentration of hydrogen sulfide gas containing relative humidity (80% RH) and the exposure time of 60, 50, 40, 30, 20, 10, and 0 seconds, respectively.

The present invention relates to a method of manufacturing a color sensor for sensing hydrogen sulfide in which a nano-size dye powder is uniformly bound to the inside and the surface of a polymer nanofiber by electrospinning. In Comparative Example 1, a color change gas sensor member was fabricated using dye powder without high energy ball milling. In Comparative Example 2, hydrogen sulfide obtained by electrospinning with a powder not subjected to a high energy ball milling process Sensory color change sensor nanofibers were prepared to compare the degree of embolus change in response to the hydrogen sulfide gas in Example 1 and to confirm the significantly improved gas sensitivity characteristics due to increase in surface area, increase in reaction sites, and increase in porosity .

FIG. 1 is a conceptual view of a color change sensor in which a nano-sized dye powder according to an embodiment of the present invention is bonded to the inside and the surface of a polymer nanofiber. As shown in FIG. 1, the diameter of the polymer nanofiber 101 may range from 50 nm to 10 .mu.m. The diameter of the nanofibers may vary depending on the viscosity of the spinning solution, the magnitude of the applied voltage, the discharge speed, and the radius of the nozzle. When the thickness of the nanofiber is thick, many dye powders are present inside the fiber, not on the surface of the fiber, and may not be able to react with the gas to be detected, which may deteriorate the sensing ability of the color change gas sensor. On the other hand, when the thickness of the nanofiber is too small, the size of the relative dye powder becomes large, so that the fiber can not be bound to the fiber, so that the powder can be simply dispersed. Therefore, the thickness of the polymer nanofiber as a support of the dye powder-polymer composite nanofiber is suitably about 50 nm to 10 μm. More preferably, the polymer nanofibers having a diameter in the range of 100 nm to 1000 nm are advantageously used for manufacturing a sensor having high structural stability and high color change intensity.

The size of the dye powder 102 bound to the polymer nanofibers is also an important factor. The size of the dye powder (either diameter, length or thickness depending on the shape of the dye powder) can be selected in the range of 10 nm to 2 占 퐉. If the size of the dye powder is small, it is possible to obtain a large surface area. However, if the polymer nanofiber is left in the polymer nanofibers during the electrospinning process, the reaction site is lost and the polymer does not react with the detection gas. On the other hand, if the size of the dye powder is too large, it does not bind to the polymer nanofibers in the electrospinning process and is present between the fibers while maintaining the original powder form. These powders block the pores in the one-dimensional nanofiber and prevent the diffusion of the detection gas and inhibit the participation of the dye attached to the nanofiber in the deep region as a reaction site. Therefore, the size of the dye powder may be effective in the range of 10 nm to 2 μm. When the size of the dye powder is in a very small size range of 10 nm to 50 nm, the number of particles contained in the polymer nanofibers is greatly increased, and the polymer nanofibers are formed so that the fine particles are exposed to the surface . Accordingly, a dye powder having a size ranging from 10 nm to 2 μm can be bound to polymer nanofibers and used as a color change sensor.

2 is a schematic diagram of an electrospinning apparatus used in Embodiment 1 of the present invention. In the electrospinning, a strong electric field is applied to the nozzle 201 at the end of the syringe by the high voltage applying device 202, and the discharged composite electric discharge liquid is radiated to the current collector 203. The solvent in the spinning solution is vaporized and the composite nanofiber is obtained. The solvent used for preparing the spinning solution is not limited to a specific solvent as long as it does not dissolve lead (II) acetate (Pb (CH 3 COO) 2 ), which is the dye used in the present invention. For example, dimethylformamide (DMF), ethanol, acetone, tetrahydrofuran, ethylene glycol, toluene, dimethylacetamide (DMAc, Dimethylacetamide and dimethylsulfoxide (DMSO), or a mixed solvent of two or more of them may be used.

The composite fiber discharged through the nozzle is a one-dimensional nanofiber. The polymer / lead (II) acetate composite color change nanofiber 204 is composed of a dye which uniformly binds to a fiber-forming polymer and reacts with a sensing gas to cause a color change. The polymer may be selected from the group consisting of cellulose, acetate butyrate, cellulose derivatives, polymethyl acrylate (PMA), polyvinyl acetate (PVAc), polymethyl methacrylate (PMMA) , Polyacrylic copolymers, polyvinyl acetate copolymers, polyvinyl alcohol (PVA), polypyryl alcohol (PPFA), polystyrene (PS), polyvinylpyrrolidone (PVP) (PEO), polypropylene oxide (PPO), polyacrylonitrile (PAN), polycarbonate (PC), polyurethane, polyurethane copolymer, cellulose acetate, Polyvinyl chloride (PVC), polycaprolactone, polyvinyl fluoride, polyaniline (PANI, Polyaniline), polyvinylidene fluoride Polyimide, styrene-acrylonitrile (SAN), polyvinyl alcohol (PVA), polycarbonate (PC), polyvinylidene fluoride (PVDF) vinylidene fluoride), polyethylene (PE), polyethylene terephthalate (PET), and polypropylene (PP). There is no particular limitation on the ratio of the content of the polymer and the solvent, but in order to have a viscosity suitable for electrospinning, it is generally preferable to select the range of 5 wt% to 30 wt% relative to the solvent.

The spinning solution injected into the nozzle contains lead (II) acetate (Pb (CH 3 COO) 2 ) dye (205) which reacts with hydrogen sulfide to change to a brownish color, and the weight ratio with the solvent is nanofiber composite (II) acetate (Pb (CH 3 COO) 2 ) in the concentration range of 50 wt% to 99 wt%. The speed of the spinning solution discharged to the nozzle can be appropriately selected according to the viscosity of the spinning solution in the range of 0.1 μL / min - 250 μL / min. The voltage applied to the nozzle can be selected between 5 kV and 30 kV, and the distance between the nozzle and the current collector can be selected from the range of 3 cm to 50 cm.

FIG. 3 is a cross-sectional view of a color change gas sensor using a polymer / lead (II) acetate composite color change nanofiber structure in which dye powder is uniformly bound to the inside and the surface of a nanofiber using an electrospinning device according to an embodiment of the present invention. The manufacturing process is schematized. The step 301 shows a nanometer-scale lead acetate (Lead (II) acetate (Pb (CH 3 COO) 2)), high-energy ball mill grinding process to proceed to obtain a dye powder. Step 302 shows a process of mixing lead (II) acetate (Pb (CH 3 COO) 2 ) dye together with a polymer in a solvent to prepare an electric discharge solution and then connecting it to the nozzle. Step (303) represents a process for preparing a polymer / lead (II) acetate complex color-changing nanofiber using an electrospinning apparatus. Step (304) Is collected in a nonwoven fabric in the form of a membrane.

The present invention will be described in more detail with reference to the following specific examples. It is to be understood that the present invention is not limited thereto.

Example  1: Synthesis of Polymer / Lead (II) acetate composite nanofiber synthesized by electrospinning

First, high-energy ball milling process is performed to reduce the size of the dye powder of 100 μm or more with sub-micron powder to make the dye powder less than 1 μm in size. FIG. 4 is a scanning electron microscope (SEM) image of a pulverized dye powder subjected to the high energy ball milling process, wherein the size (any one of a diameter, a length and a thickness depending on the shape of the nano powder) is in a range of 10 nm to 2 μm Powder was obtained.

0.65 g of lead (II) acetate lead (Pb (CH 3 COO) 2 ), which had undergone the ball milling process, and polymethyl methacrylate (PMMA) having a molecular weight of 350,000 g methacrylate (0.15 g) are stirred in 2 ml of dimethylformamide (DMF, dimethylformamide) at 50 ° C for 10 hours. Connect the spinning solution to the nozzle.

A voltage of 17 kV is applied to the nozzle to advance the electrospinning, and the distance between the nozzle and the current collector is maintained at 15 cm. Also, the discharge speed of the nozzle is maintained at 0.3 mL / min.

5 is a scanning electron microscopic photograph of a dye powder-polymer composite nanofiber (or polymer-dye powder composite nanofiber) synthesized through the above electrospinning. In the polymer nanofiber having a diameter of about 800 nm, a submicron dye It can be confirmed that the powder is well bonded, and it can be confirmed that the nanofibers of 1 μm or less are uniformly obtained as a whole.

Comparative Example 1. Pure lead (II) acetate (Pb (CH 3 COO) 2 ) Dye powder

In Comparative Example 1, unlike Example 1, the pure dye powder provided without the electrospinning process was used.

6 is a scanning electron microscope (SEM) image of pure dye powder not subjected to an electrospinning process. As a result, it can be confirmed that the size of the inherent dye powder is 100 μm or more.

Comparative Example  2. Ball milling  Unprocessed dye powder Concluded  Polymer / Lead (II) acetate complex color change nanofiber

(Lead (II) acetate (Pb (CH 3 COO) 2 )) and polymethyl methacrylate (PMMA, molecular weight: 350,000 g), which are commercially available, methacrylate (0.15 g) were stirred in 2 ml of dimethylformamide (DMF, dimethylformamide) at 50 ° C for 48 hours. Connect the spinning solution to the nozzle.

A voltage of 17 kV is applied to the nozzle to advance the electrospinning, and the distance between the nozzle and the current collector is maintained at 15 cm. Also, the discharge speed of the nozzle is maintained at 0.3 mL / min.

7 is a scanning electron micrograph of the dye powder-polymer composite nanofiber obtained through the electrospinning. The diameter of the obtained polymer nanofibers is found to be in the vicinity of 600 nm, and shows a bundle of nanofibers in which the dye is bound. In some cases, large lumps of dyes attached to the nanofibers fail to maintain the shape of the nanofibers. If the ball milling does not proceed, a large amount of particles larger than 1 μm are generated due to the pulverization of the stirring process. Therefore, it is possible to maintain a uniform nanofiber shape by obtaining a dye powder mixture having an appropriate size through ball milling.

The polymer / lead (II) acetate composite color change nanofibers synthesized by the electrospinning of the present invention exhibited excellent detection characteristics as compared with the comparative examples, and thus, even in the case of a slight amount of hydrogen sulfide gas, Can be confirmed.

Experimental Example  1. Polymer / Lead (II) acetate composite color change nanofiber synthesized by electrospinning, dyestuff powder and ball without electrospinning process milling  The dye / powder (II) acetate complex obtained by electrospinning process Color change  Evaluation of color change characteristics of hydrogen sulfide gas using nanofiber

To evaluate the color change characteristics of the hydrogen sulfide gas, the above members were directly exposed to hydrogen sulfide (H 2 S) gas for 1 minute while changing the gas concentration to 5, 4, 3, 2, 1 ppm in a dry environment without humidity The color change characteristics of the gas were evaluated.

FIG. 8 is a graph showing the relationship between the concentration of hydrogen sulfide gas and the concentration of hydrogen sulfide gas in the case of Example 1, Comparative Example 1, and Comparative Example 2, in which the concentration of hydrogen sulfide gas was reduced to 5, 4, 3, 2 and 1 ppm for 1 minute in a dry environment without moisture at room temperature And the degree of color change seen when it is observed.

As shown in FIG. 8, the polymer / lead (II) acetate complex color-changing nanofibers subjected to a high energy ball milling and electrospinning process can visually detect a distinct color change at 1 ppm, Dye powder that has not undergone the process can observe a distinct color change up to 3 ppm with the naked eye. In the case of nanofibers obtained from dye powders without ball milling, a clear color change up to 2 ppm can be visually recognized. Polymer / Lead (II) acetate composite color change nanofibers synthesized by electrospinning with nano - sized powders were prepared by dyestuff powders which did not undergo electrospinning process for hydrogen sulfide gas and polymer / Lead (II) acetate composite color change nanofibers exhibit more pronounced color change when they are exposed to low hydrogen sulfide gas.

FIG. 9 shows that Example 1 reduced the concentration of hydrogen sulfide gas to 5, 4, 3, 2, and 1 ppm, including the relative humidity (80% RH), which is similar to the humidity of dry humidified hydrogen sulfide gas And the degree of color change when exposed directly for 1 minute.

As shown in Fig. 9, similar embolization is shown in dry and humid environments. Through the distinct color change from white to brown system, it was possible to distinguish the concentration up to 1 ppm visually, and it can be seen that the color change occurs well even in a high humidity environment (80% RH). In addition, when exposed to dry hydrogen sulfide gas, it becomes dark brown, whereas when it is exposed to hydrogen sulfide gas containing moisture, it can be confirmed that the color changes to brown generally.

10 shows the degree of color change when Example 1 reduces the exposure time to 1 ppm hydrogen sulfide gas containing relative humidity (80% RH) to 60, 50, 40, 30, 20, 10, As shown in FIG. 10, it can be confirmed that the brown color, which was evident at 1 ppm, became thinner as the exposure time was shortened. Visually, the color change of the nanofiber membrane exposed to hydrogen sulfide gas for 20 seconds can be detected.

Claims (17)

Wherein the dye material causing color change through reaction with gas molecules comprises a composite nanofiber membrane bound to a polymer having a nanometer size fiber structure,
The composite nanofiber membrane is pulverized through a pulverization process so that the dye material having a nanometer or submicron size is dispersed in the solvent in a state of being not dissolved in a solvent used for producing the nanofiber, Wherein the nanofibers are exposed to the inner and outer surfaces of the nanofibers in the course of manufacturing the nanofibers and change their color through reaction with the gas molecules. The method according to claim 1,
Wherein the dye material comprises lead (II) acetate (Pb (CH 3 COO) 2 ) which changes color upon reaction with hydrogen sulfide (H 2 S) gas. . The method according to claim 1,
As the dye material Lead (II) acetate (Pb ( CH 3 COO) 2) is exposed to the interior and the outside surface of the nanofibers, hydrogen sulfide (H 2 S) gas and the Lead (II) acetate (Pb ( CH 3 COO ) 2 ), the color of the dye powder / polymer composite gas indicating nanofiber sensor is changed. The method according to claim 1,
Wherein the dye material is bound to the polymer in nanometer or submicron sized powder form. The method according to claim 1,
Wherein the fiber structure comprises a one-dimensional shape. ≪ RTI ID = 0.0 > 21. < / RTI > The method according to claim 1,
(II) acetate (Pb (CH 3 COO) 2 ) as the dye material is bound to the inside and the surface of the polymer nanofiber obtained by electrospinning in order to form the nanofiber composite without desorption of the dye material Dye powder / polymer composite gas indicating nanofiber sensor. The method according to claim 1,
Wherein the diameter of the dye powder / polymer composite nanofiber included in the composite nanofiber membrane is in the range of 50 nm to 10 μm. The method according to claim 1,
Wherein the weight ratio of lead (II) acetate (Pb (CH 3 COO) 2 ) bound to the dye material in the composite nanofiber membrane is in the range of 0.5 wt% to 90 wt% with respect to the polymer Dye powder / polymer composite gas indicating nanofiber sensor. A method for producing a dye powder / polymer composite nanofiber sensor,
(a) pulverizing a dye material through a high-energy ball-milling process to prepare a dye powder having a nanometer or submicron size;
(b) preparing a dye powder / polymer composite electrospinning solution in which a dye powder is dispersed in a polymer solution by mixing the prepared dye powder and polymer in a solvent in which the dye powder is not dissolved;
(c) forming a composite nanofiber in which the polymer and the dye powder are bound to each other by an electrospinning method so that the dye powder remains uniformly on the inside and on the surface;
(d) directly spinning the composite nanofibers formed by the electrospinning method on the nonwoven fabric to form a dye powder / polymer composite nanofiber membrane;
Polymer nanofiber sensor according to any one of claims 1 to 5. 10. The method of claim 9,
The step (a)
Wherein the dye powder is pulverized to have a uniform particle size through a high energy ball milling process. 10. The method of claim 9,
Wherein the dye powder produced through the high energy ball milling process has an average diameter ranging from 10 nm to 2 占 퐉. 10. The method of claim 9,
Wherein the dye material comprises lead (II) acetate (Pb (CH 3 COO) 2 ). 10. The method of claim 9,
The polymer may be selected from the group consisting of cellulose, acetate butyrate, cellulose derivatives, PMA, polyvinyl acetate, polymethyl methacrylate (PMMA), polymethyl methacrylate methacrylate, polyacrylic copolymer, polyvinyl acetate copolymer, polyvinyl alcohol (PVA), polypyryl alcohol (PPFA), polystyrene (PS), polyvinylpyrrolidone (PVP) (PEO), polypropylene oxide (PPO), polyacrylonitrile (PAN), polycarbonate (PC), polyurethane, polyurethane copolymer, cellulose acetate ), Polyvinyl chloride (PVC), polycaprolactone, polyvinyl fluoride, polyaniline (PANI, Polyaniline), polyvinylidene fluoride Polyimide, styrene-acrylonitrile (SAN), polyvinyl alcohol (PVA), polycarbonate (PC), polyvinylidene fluoride (PVDF), poly polymer composite nanofibers characterized by comprising at least one polymer selected from the group consisting of vinylidene fluoride, polyethylene, polyethylene terephthalate and polypropylene. A method of manufacturing a sensor. 10. The method of claim 9,
Wherein the weight ratio of the solvent is in the range of 50 wt% to 99 wt% with respect to lead (II) acetate (Pb (CH 3 COO) 2 ) contained in the composite nanofiber as the dye powder. (Method for manufacturing powder / polymer composite nanofiber sensor). 10. The method of claim 9,
The solvent is selected from the group consisting of dimethylformamide, ethanol, acetone, tetrahydrofuran, ethylene glycol, toluene, dimethylacetamide (DMAc, Wherein the solvent comprises a solvent selected from the group consisting of dimethylacetamide, dimethylacetamide, and dimethyl sulfoxide (DMSO), or a mixed solvent of two or more thereof. 10. The method of claim 9,
Wherein the thickness of the dye powder / polymer composite nanofiber membrane is in the range of 5 μm to 100 μm. 10. The method of claim 9,
When the dye powder / polymer composite nanofiber membrane is exposed to hydrogen sulfide (H 2 S) gas, the reaction between the dye powder and the hydrogen sulfide gas in the individual nanofibers, including the dye powder / polymer composite nanofiber membrane, Wherein a color change occurs and a visually recognizable color change is made at a concentration of 1 ppm or less of the hydrogen sulfide gas.
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