High-sensitivity acid-base gas response type developing sensing label and preparation method thereof

Abstract

The invention relates to the technical field of sensors, and particularly discloses a high-sensitivity acid-base gas response type chromogenic sensing label and a preparation method thereof, and the preparation method of the chromogenic sensing label comprises the following steps: preparing a high-molecular polymer spinning solution; preparing an electrostatic spinning solution 1 containing an alkaline detection discoloration solution; preparing an electrostatic spinning solution 2 containing an acidity detection discoloration solution; respectively spinning the obtained electrostatic spinning solution 1 and the electrostatic spinning solution 2 to form a mixed fiber membrane; and performing post-processing to obtain the color developing sensing label. Through the steps, the nanofiber color-developing sensing label loaded with the acidic and alkaline color-developing materials is obtained, so that the nanofiber color-developing sensing label has a detection effect on acidic and alkaline pollution gases, and the detection singleness of a conventional sensing label is overcome.

Description

Technical Field

[0001] The present invention belongs to the technical field of sensors, and in particular relates to a highly sensitive acid-base gas responsive colorimetric sensor label and a preparation method thereof. Background Art

[0002] A gas sensor is a device that converts gas information, including concentration and type, into usable data. By leveraging the physical and chemical properties of various gases, it converts changes in the monitored gases in the environment into distinct response signals, enabling accurate and effective control and application. Among the different response types, colorimetric sensor tags use visible color changes as their response signal. This direct visualization eliminates the need for any additional monitoring components, making them suitable for the development of intelligent monitoring devices with instant response.

[0003] Compared to conventional filter paper, the nanoscale fiber network-based colorimetric sensor tags obtained by electrospinning technology have core advantages such as high specific surface area, high porosity and adjustable microstructure. These characteristics significantly enhance the adsorption and diffusion of gas molecules, enabling more sensitive detection of target substances. For example, patent CN110384990B discloses a functionalized nanofiber three-dimensional mesh flexible sensing film and its preparation method and application. The functionalized solution is uniformly loaded on the surface of the polymer network skeleton by soaking or spraying. The functionalized solution used contains metal porphyrin or platinum isocyanide, so that the obtained sensing film can be used for visual detection of gases such as formaldehyde, ethanol, acetone, and benzene at room temperature. However, the detection gases of the above patents are mostly organic vapors. Considering the current diversity of pollutant gases, there is an urgent need on the market for a sensor tag that can detect multiple pollutant gases. Summary of the Invention

[0004] In order to overcome the above-mentioned deficiencies of the prior art, the present application co-spins nanofibers loaded with acidic and alkaline color-developing materials into fiber membranes through mixed spinning, so that the membranes have excellent detection effects on both acidic and alkaline pollutant gases.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is: In one aspect, the present invention provides a method for preparing a highly sensitive acid-base gas responsive colorimetric sensor label, comprising the following steps: (1) dissolving a polymer in water at 70 to 90° C. to obtain a spinning solution having a polymer concentration of 8 to 12 wt %; (2) adding the alkaline detection color-changing solution to the spinning solution and stirring at room temperature until completely dissolved to obtain an electrospinning solution 1; (3) adding the acidic detection color-changing solution to the spinning solution and stirring at room temperature until completely dissolved to obtain electrospinning solution 2; (4) The obtained electrospinning solutions 1 and 2 are respectively injected into an electrospinning device, and electrospinning is performed at room temperature and a receiving distance of 10 to 25 cm to obtain a mixed fiber membrane; the mixed fiber membrane is vacuum dried to a constant weight and cut to obtain the colorimetric sensor label.

[0006] In this application, nanofibers loaded with acidic and alkaline color-developing materials are alternately distributed and co-spun into a fiber membrane through mixed spinning, so that it can detect both acidic and alkaline pollutant gases and achieve dual-mode response. When facing alkaline gas, the color-developing sensor label displays red, and when facing acidic gas, the label displays blue-green.

[0007] In some embodiments, in step (1), the high molecular weight polymer comprises polyvinyl alcohol and polyacrylic acid.

[0008] In some embodiments, the mass ratio of the polyvinyl alcohol to polyacrylic acid is 1:(0.3-0.4).

[0009] This application uses polyvinyl alcohol and polyacrylic acid as the core components of the spinning solution, wherein the carboxylic acid groups on the polyacrylic acid molecular chain form hydrogen bonds with the hydroxyl groups of the polyvinyl alcohol, reducing the entanglement of the molecular chains and improving the spinnability of the spinning solution; and the introduction of polyacrylic acid can interfere with the crystallization of polyvinyl alcohol, forming an amorphous-microcrystalline composite structure, making the fiber diameter thinner and more evenly distributed; at the same time, by adjusting the ratio of the two, the solution viscosity is improved and the bead defects on the fiber surface are reduced.

[0010] In some embodiments, in step (2), the preparation steps of the alkaline detection color-changing solution are as follows: dissolving dichlorophenolsulfonphthalein, cyanuric chloride and triethylamine in acetone, reacting at 50-70°C for 2-4 hours, cooling to room temperature, and rotary evaporation to obtain a precipitate. At room temperature, the precipitate is dissolved in ethylene glycol methyl ether, and triethylamine is added to obtain the alkaline detection color-changing solution.

[0011] When preparing an alkaline detection color-changing solution, the present application converts the sulfate group of dichlorophenolsulfonphthalein into sulfonic acid chloride. The strong electron-withdrawing property of the sulfonic acid chloride reduces the electron cloud density of the phenol ring, promotes the deprotonation of the phenolic hydroxyl group under alkaline conditions, thereby extending the conjugated chain and improving the detection sensitivity; and the strong oxidizing property of sulfonic acid chloride can inhibit the oxidative degradation of the color-developing molecules; at the same time, the high solubility of sulfonic acid chloride in polar solvents such as ethylene glycol methyl ether can ensure the uniform dispersion of the color-developing molecules in the spinning solution.

[0012] In some embodiments, the mass ratio of dichlorophenolsulfonphthalein to cyanuric chloride is 1:(0.2-0.4).

[0013] The present application improves the yield of the target product by controlling the mass ratio of dichlorophenolsulfonphthalein to cyanuric chloride.

[0014] In some embodiments, the mass ratio of the precipitate to the high molecular weight polymer in step (1) is (0.001-0.004):1.

[0015] In some embodiments, in step (3), the preparation steps of the acidic detection color-changing solution are as follows: Under nitrogen protection at room temperature, 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin, dichloromethane and triethylamine are stirred and mixed, and then 3-methylcrotonyl chloride is added and stirred for 10 to 12 hours. The mixture is distilled under reduced pressure, the organic phase is extracted, dried, recrystallized, and redissolved in N,N-dimethylformamide to obtain an acid detection color-changing solution.

[0016] Under acidic gas conditions, porphyrin molecules undergo protonation reactions, changing the charge distribution and intermolecular interactions, causing a color change. On this basis, the acylation reaction of 3-methylcrotonoyl chloride modifies the hydroxyl group into an ester group, making it more susceptible to proton attack, thereby improving detection sensitivity.

[0017] In some embodiments, the concentration of the acidic detection color-changing solution is 2 to 5 g / L.

[0018] In some embodiments, in step (3), the mass ratio of the acidic detection color-changing solution to the spinning solution is 1:(40-60).

[0019] In some embodiments, in step (4), the electrospinning rate is 0.5 to 1.5 mL·h -1 , voltage is 14~24kV. This application controls the electrospinning parameters to avoid insufficient solvent volatilization or weakening of the electric field force, thereby ensuring that the obtained fibers have few surface defects and uniform diameter.

[0020] Another aspect of the present invention provides a colorimetric sensor tag obtained by the above-mentioned preparation method. The colorimetric sensor tag can detect gases including hydrogen chloride gas and amino-containing gas.

[0021] Compared with the prior art, the present invention has the following beneficial effects: 1. The present application provides a highly sensitive acid-base gas responsive colorimetric sensor tag, which overcomes the single detection characteristic of conventional sensor tags. By mixed spinning, nanofibers loaded with acidic and alkaline colorimetric materials are alternately distributed and co-spun into a fiber membrane, so that it can detect both acidic and alkaline pollutant gases, thus achieving dual-mode response.

[0022] 2. The present application obtains a spinning solution by compounding high molecular polymers, and the prepared fibers have a finer diameter and are evenly distributed, with reduced surface bead defects; and the synergy of high molecular polymers polyvinyl alcohol and polyacrylic acid is also beneficial for fixing the color-developing molecules through hydrogen bonds, preventing the color-developing molecules from migrating or aggregating, and ensuring the uniformity of the color-developing signal.

[0023] 3. The present application improves the detection sensitivity and antioxidant properties of the sensor tag to alkaline and acidic gases by increasing the activity of dichlorophenolsulfonphthalein in the alkaline color-developing material and the receiving sensitivity of the porphyrin ring in the alkaline color-developing material. DETAILED DESCRIPTION

[0024] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following examples are illustrative of the present invention and are intended only to illustrate the present invention and are not intended to limit the present invention. Other combinations and various modifications within the scope of the present invention may be made without departing from the spirit or scope of the present invention.

[0025] It is worth noting that the raw materials used in the following preparation examples and embodiments, unless otherwise specified, were obtained from any commercially available manufacturer: The polyvinyl alcohol model is 1799; the number average molecular weight of polyacrylic acid is 400000±1000.

[0026] Preparation Example 1 The preparation steps of alkaline detection color changing solution A are as follows: Dissolve 10 g of dichlorophenolsulfonphthalein, 3 g of cyanuric chloride, and 2 g of triethylamine in 250 g of acetone, react at 60°C for 3 h, cool to room temperature, and rotary evaporate to obtain a precipitate. At room temperature, dissolve 2 g of the precipitate in 120 g of ethylene glycol methyl ether, and then add 3.5 g of triethylamine to obtain alkaline detection color-changing solution A.

[0027] Preparation Example 2 The preparation steps of alkaline detection color changing solution B are as follows: Dissolve 2 g of dichlorophenolsulfonphthalein in 120 g of ethylene glycol methyl ether, and then add 3.5 g of triethylamine to obtain alkaline detection color-changing solution B.

[0028] Preparation Example 3 The preparation steps of acid detection color-changing solution A are as follows: under nitrogen protection at room temperature, 20g of 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin, 2L of dichloromethane and 100mL of triethylamine are stirred and mixed, and then 100mL of 3-methylcrotonyl chloride is added. The mixture is stirred for 12 hours, and the organic phase is distilled under reduced pressure, extracted, dried, recrystallized, and redissolved in N,N-dimethylformamide to obtain acid detection color-changing solution A with a concentration of 4g / L.

[0029] Preparation Example 4 The steps for preparing the acid detection color-changing solution B are as follows: dissolving 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin in N,N-dimethylformamide to obtain the acid detection color-changing solution B with a concentration of 4 g / L.

[0030] Example 1 A method for preparing a highly sensitive acid-base gas responsive colorimetric sensor label comprises the following steps: (1) dissolving 20 g of polyvinyl alcohol and 7 g of polyacrylic acid in water at 80° C. to obtain a spinning solution having a polymer concentration of 10 wt %; (2) Add 1.8 g of alkaline detection color-changing solution A to 100 g of spinning solution and stir at room temperature until completely dissolved to obtain electrospinning solution 1; (3) Add 2 g of acidic detection color-changing solution A to 100 g of spinning solution and stir at room temperature until completely dissolved to obtain electrospinning solution 2; (4) 100 g of each of the electrospinning solutions 1 and 2 were injected into the electrospinning device at room temperature at a spinning rate of 1 mL·h -1 Electrospinning was performed under conditions of a voltage of 20 kV and a receiving distance of 20 cm to obtain a mixed fiber membrane; the mixed fiber membrane was vacuum dried at 40° C. to a constant weight and cut to obtain a colorimetric sensor label.

[0031] Example 2 A method for preparing a highly sensitive acid-base gas responsive colorimetric sensor label comprises the following steps: (1) dissolving 20 g of polyvinyl alcohol and 6 g of polyacrylic acid in water at 70° C. to obtain a spinning solution having a polymer concentration of 8 wt %; (2) adding 0.5 g of alkaline detection color changing solution A to 100 g of spinning solution and stirring at room temperature until completely dissolved to obtain electrospinning solution 1; (3) Add 1.7 g of acidic detection color-changing solution A to 100 g of spinning solution and stir at room temperature until completely dissolved to obtain electrospinning solution 2; (4) 100 g of each of the electrospinning solutions 1 and 2 were injected into the electrospinning device at room temperature at a spinning rate of 0.5 mL h -1 Electrospinning was performed under conditions of a voltage of 14 kV and a receiving distance of 10 cm to obtain a mixed fiber membrane; the mixed fiber membrane was vacuum dried to a constant weight and cut to obtain a colorimetric sensor label.

[0032] Example 3 A method for preparing a highly sensitive acid-base gas responsive colorimetric sensor label comprises the following steps: (1) dissolving 20 g of polyvinyl alcohol and 8 g of polyacrylic acid in water at 90° C. to obtain a spinning solution having a polymer concentration of 12 wt %; (2) Add 2.8 g of alkaline detection color change solution A to 100 g of spinning solution and stir at room temperature until completely dissolved to obtain electrospinning solution 1; (3) Add 2.5 g of acidic detection color-changing solution A to 100 g of spinning solution and stir at room temperature until completely dissolved to obtain electrospinning solution 2; (4) 100 g of each of the electrospinning solutions 1 and 2 were injected into the electrospinning device at room temperature at a spinning rate of 1.5 mL·h -1 Electrospinning was performed under conditions of a voltage of 24 kV and a receiving distance of 25 cm to obtain a mixed fiber membrane; the mixed fiber membrane was vacuum dried to a constant weight and cut to obtain a colorimetric sensor label.

[0033] Example 4 This embodiment provides a method for preparing a highly sensitive acid-base gas responsive colorimetric sensor tag. The specific implementation method is the same as that of Example 1, except that the alkaline detection color-changing solution A is replaced by an equal amount of alkaline detection color-changing solution B.

[0034] Example 5 This embodiment provides a method for preparing a highly sensitive acid-base gas responsive colorimetric sensor label. The specific implementation method is the same as that of Example 1, except that the acid detection color-changing solution A is replaced by an equal amount of acid detection color-changing solution B.

[0035] Example 6 This embodiment provides a method for preparing a highly sensitive acid-base gas responsive colorimetric sensor tag. The specific implementation method is the same as that of Example 1, except that: (1) 27 g of polyvinyl alcohol was dissolved in water at 80°C to obtain a spinning solution with a polymer concentration of 10 wt%.

[0036] Example 7 This embodiment provides a method for preparing a highly sensitive acid-base gas responsive colorimetric sensor tag. The specific implementation method is the same as that of Example 1, except that: (1) 27 g of polyacrylic acid was dissolved in water at 80°C to obtain a spinning solution with a polymer concentration of 10 wt%.

[0037] Performance testing: 1. NH3 sensing test: The colorimetric sensor tags obtained in Examples 1 to 6 were placed in a gas detection system to test their sensing performance in NH3. The gas detection system consists of a sealed, transparent sample chamber, an air pump, and a Fourier transform gas infrared analyzer. Ammonia water was injected into the air pump outlet with a microsyringe. The ammonia water vaporized into NH3 gas in a short period of time and circulated throughout the reaction system. At the same time, the Fourier transform gas infrared analyzer could detect the NH3 concentration in real time. The NH3 concentration was recorded by visual observation when the sensor tag changed color.

[0038] 2. HCl Sensing Test: The colorimetric sensor tags obtained in Examples 1 to 6 were placed in a gas detection system to test their sensing performance in HCl. The gas detection system consists of a sealed, transparent sample chamber, an air pump, and a Fourier transform infrared gas analyzer. Hydrochloric acid is injected into the air pump outlet using a microsyringe. The hydrochloric acid vaporizes into HCl gas in a short period of time and circulates throughout the reaction system. The Fourier transform infrared gas analyzer can detect the HCl concentration in real time. The HCl concentration is recorded by visual observation when the sensor tag changes color.

[0039] The above results are shown in Table 1.

[0040] Table 1 It can be seen from the data in Table 1 that the colorimetric sensor tags of Examples 1 to 7 showed color development in both NH3 gas and HCl gas environments, indicating that the colorimetric tags have detection effects on both acidic and alkaline gases. Among them, the colorimetric sensor tags of Examples 1 to 3 have higher detection sensitivity for the detection of the two gases. Compared with Example 1, the alkaline detection material of Example 4 did not convert the sulfate group into sulfonic acid chloride, which reduced the sensitivity of the sensor tag to ammonia; the acidic detection material of Example 5 did not optimize the porphyrin, resulting in a decrease in the detection sensitivity of the sensor tag to HCl gas. Compared with Example 1, Examples 6 to 7 respectively used a single polymer as the spinning solution, resulting in a decrease in the sensitivity of the obtained sensor tags to NH3 gas and HCl gas. The possible reason is that a single polymer is not conducive to the fixation of the colorimetric molecules during spinning.

[0041] The embodiments described above do not impose any form of limitation on the present invention. Although the present invention has been disclosed as a preferred embodiment as above, it is not intended to limit the present invention. Any technician familiar with the present profession can make some changes or modifications to equivalent embodiments using the technical content disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a highly sensitive acid-base gas responsive colorimetric sensor label, characterized in that: The following steps are involved: (1) dissolving a polymer in water at 70 to 90° C. to obtain a spinning solution having a polymer concentration of 8 to 12 wt %; (2) adding the alkaline detection color-changing solution to the spinning solution and stirring at room temperature until completely dissolved to obtain an electrospinning solution 1; (3) adding the acidic detection color-changing solution to the spinning solution and stirring at room temperature until completely dissolved to obtain electrospinning solution 2; (4) The obtained electrospinning solutions 1 and 2 are respectively injected into an electrospinning device, and electrospinning is performed at room temperature and a receiving distance of 10 to 25 cm to obtain a mixed fiber membrane; the mixed fiber membrane is vacuum dried to a constant weight and cut to obtain the colorimetric sensor label.

2. The method for preparing a highly sensitive acid-base gas responsive colorimetric sensor tag according to claim 1, wherein: In step (1), the high molecular polymer comprises polyvinyl alcohol and polyacrylic acid.

3. The method for preparing a highly sensitive acid-base gas responsive colorimetric sensor tag according to claim 2, wherein: The mass ratio of the polyvinyl alcohol to the polyacrylic acid is 1:(0.3-0.4).

4. The method for preparing a highly sensitive acid-base gas responsive colorimetric sensor tag according to claim 1, wherein: In step (2), the preparation steps of the alkaline detection color-changing solution are as follows: Dissolve dichlorophenolsulfonphthalein, cyanuric chloride and triethylamine in acetone, react at 50-70°C for 2-4 hours, cool to room temperature, and rotary evaporate to obtain a precipitate. Dissolve the precipitate in ethylene glycol methyl ether at room temperature, and then add triethylamine to obtain an alkaline detection color-changing solution.

5. The method for preparing a highly sensitive acid-base gas responsive colorimetric sensor tag according to claim 4, wherein: The mass ratio of the dichlorophenolsulfonphthalein to cyanuric chloride is 1:(0.2-0.4).

6. The method for preparing a highly sensitive acid-base gas responsive colorimetric sensor tag according to claim 4, wherein: The mass ratio of the precipitate to the high molecular weight polymer in step (1) is (0.001-0.004):

1.

7. The method for preparing a highly sensitive acid-base gas responsive colorimetric sensor tag according to claim 1, wherein: In step (3), the preparation steps of the acid detection color-changing solution are as follows: Under nitrogen protection at room temperature, 5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin, dichloromethane and triethylamine are stirred and mixed, and then 3-methylcrotonyl chloride is added and stirred for 10 to 12 hours. The mixture is distilled under reduced pressure, the organic phase is extracted, dried, recrystallized, and redissolved in N,N-dimethylformamide to obtain an acid detection color-changing solution.

8. The method for preparing a highly sensitive acid-base gas responsive colorimetric sensor tag according to claim 7, wherein: The concentration of the acid detection color-changing solution is 2 to 5 g / L.

9. The method for preparing a highly sensitive acid-base gas responsive colorimetric sensor tag according to claim 1, wherein: In step (4), the electrospinning rate is 0.5-1.5 mL·h -1 , voltage is 14~24kV.

10. A highly sensitive acid-base gas responsive colorimetric sensor tag obtained according to the preparation method according to any one of claims 1 to 9, characterized in that: The gases that can be detected by the colorimetric sensor tag include hydrogen chloride gas and amino-containing gas.

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