A fluorescent polymer with acid-base stimulus responsiveness and preparation method and application thereof

Abstract

The present invention belongs to the field of functional materials, and discloses a fluorescent polymer with acid-base stimulus responsiveness, and a preparation method and application thereof. The preparation method comprises the following steps: the first step is to polymerize a dibasic acetylene aldehyde compound and a dibasic thiol compound in an organic solvent under an inert or air atmosphere, and after the reaction is completed, the product is dissolved in an organic solvent, added to n-hexane for precipitation, and a β-aldehyde polysulfide is obtained; the second step is to react the β-aldehyde polysulfide with a hydrazine or acylhydrazine compound in an organic solvent under an air atmosphere to obtain a fluorescent polysulfide solution with acid-base stimulus responsiveness. The fluorescent polysulfide with acid-base stimulus responsiveness prepared by the polymerization method of the present invention utilizes its excellent properties such as rapid acid-base response, obvious fluorescence change, and good reversibility to realize its high-tech applications in patterning and multicolor display, copy materials, food detection, information encryption and storage, etc.

Description

Technical Field

[0001] The invention belongs to the field of functional materials, and specifically relates to a fluorescent polymer with acid-base stimulus responsiveness, a preparation method and an application thereof. Background Art

[0002] Stimuli-responsive materials are a type of "intelligent" molecules that can respond to external environmental influences such as light, temperature, pressure, humidity, pH, etc. by generating corresponding response signals, such as color changes, changes in electronic properties, mechanical properties and other physical and chemical properties, and can then be used as sensors, detectors and probes, etc., showing great application potential in many fields such as physical chemistry, materials science, biology and medicine. Among them, acid-base homeostasis plays a vital role in biochemical and physiological processes, and acid-base anomalies can pose a huge threat to ecological balance and human health. Therefore, it is very necessary to develop fast, sensitive and switchable acid-base response technologies.

[0003] Photoluminescence has attracted wide attention due to its advantages such as high sensitivity, fast response speed and convenient operation. Thanks to the development of fluorescent materials, a variety of fluorescent materials with acid-base response have been reported. However, most of the work in this field focuses on fluorescent small molecules; in comparison, polymer-based fluorescent materials have more advantages, such as signal amplification effect, good processability and convenient post-modification. Therefore, polymer-based fluorescent materials and applications based on acid-base response are still under development. Summary of the invention

[0004] In view of the shortcomings and deficiencies of the above prior art, the primary purpose of the present invention is to provide a method for preparing fluorescent polythioether with acid-base stimulus responsiveness.

[0005] Another object of the present invention is to provide a fluorescent polythioether responsive to acid-base stimulation, which is obtained by the above-mentioned preparation method.

[0006] Another object of the present invention is to provide the application of the above fluorescent polythioether with acid-base stimulus responsiveness in patterning and multicolor display.

[0007] Another object of the present invention is to provide the use of the fluorescent polysulfide having acid-base stimulus responsiveness in a copy material.

[0008] Another object of the present invention is to provide the application of the fluorescent polysulfide having acid-base stimulus responsiveness in food detection.

[0009] Another object of the present invention is to provide an application of the fluorescent polysulfide having acid-base stimulus responsiveness in information encryption and storage.

[0010] The object of the present invention is achieved by the following technical scheme: A method for preparing a fluorescent polythioether with acid-base stimulus responsiveness, comprising the following preparation steps: a first step, in an inert or air atmosphere, polymerizing a dibasic acetylene aldehyde compound of formula (I) and a dibasic thiol compound of formula (II) in an organic solvent, after the reaction is completed, dissolving the product in an organic solvent, adding it to n-hexane for precipitation, collecting the precipitate, and drying it to constant weight to obtain a β-aldehyde polythioether of formula (III);

[0011] The second step is to react the β-aldehyde polysulfide of formula (III) with hydrazine or hydrazide compound in an organic solvent under air atmosphere to obtain a fluorescent polysulfide solution with acid-base stimulus responsiveness; or to dissolve the product in an organic solvent, add it to n-hexane for precipitation, collect the precipitate, and dry it to constant weight to obtain a fluorescent polysulfide with acid-base stimulus responsiveness of formula (IV);

[0012]

[0013] Wherein, n is an integer from 2 to 200, R 1 , R 2 are the same or different aromatic groups, and R is an amino group, an amide group containing 1 to 12 carbon atoms, or a polymer chain of formula (III) having an imine group.

[0014] Furthermore, the R 1 is any one of the following chemical structural formulas (1) to (8), wherein R 2 Any one of the following chemical structural formulas (9) to (16):

[0015]

[0016] Wherein, m and h are integers of 1 to 15; X is a C, O or S element, and * indicates a substitution position.

[0017] Furthermore, the organic solvent in the first step and the second step is one or a mixture of two or more of tetrahydrofuran, dimethyl sulfoxide, N,N-dimethylformamide, dimethylacetamide, and chloroform; the first step is preferably N,N-dimethylformamide, and the second step is preferably tetrahydrofuran.

[0018] Furthermore, in the first step, the polymerization reaction temperature is 20-80° C., and the polymerization reaction time is 1-6 hours; in the second step, the reaction temperature is room temperature, and the reaction time is 1 minute to 1 hour.

[0019] Furthermore, in the first step, the molar ratio of the dibasic acetylenic aldehyde compound to the dibasic thiol compound is 1:(1-1.1); and in the second step, the molar ratio of the β-aldehyde polysulfide to the hydrazine or hydrazide compound is 1:(0.001-0.05).

[0020] Furthermore, in the first step, the concentration of the dibasic acetylenic aldehyde compound in the organic solvent is 0.05-0.5 mol / L, preferably 0.2-0.3 mol / L; in the second step, the concentration of the β-aldehyde polysulfide in the organic solvent is 0.005-0.1 mol / L, preferably 0.01 mol / L.

[0021] The present invention also provides a fluorescent polythioether with acid-base stimulus responsiveness, which is prepared by the above-mentioned preparation method.

[0022] The above-mentioned fluorescent polysulfide with acid-base stimulus responsiveness is used in patterning and multicolor display.

[0023] Application of the above fluorescent polysulfide with acid-base stimulus responsiveness in copy materials.

[0024] The above-mentioned fluorescent polysulfide with acid-base stimulus responsiveness is used in food detection.

[0025] The above-mentioned fluorescent polysulfide with acid-base stimulus responsiveness is used in information encryption and storage.

[0026] The preparation method of the present invention and the obtained product have the following advantages and beneficial effects:

[0027] (1) The electron-withdrawing properties of the aldehyde group make acetylenic monomers highly reactive, allowing them to polymerize with thiol compounds under non-catalytic conditions. The polymerization method is simple and efficient, and can synthesize polymers with high molecular weight.

[0028] (2) The polymerization process of the present invention generates no by-products and is atom-economical.

[0029] (3) The reaction of β-aldehyde polysulfide with hydrazine or acylhydrazide compounds is highly efficient, and fluorescent polysulfide with acid-base responsiveness can be obtained after only 1 min of reaction at room temperature.

[0030] (4) The fluorescent polysulfide prepared by the polymerization method of the present invention has excellent properties such as rapid acid-base response, obvious fluorescence change, and good reversibility, and realizes its high-tech applications in patterning and multi-color display, copy materials, food testing, information encryption and storage, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Fluorescence spectrum of the acid-base responsive fluorescent polysulfide P1-1 after acid-base fumigation.

[0032] Figure 2 The number of cycles of the acid-base responsive fluorescent polysulfide P1-1 after acid-base fumigation.

[0033] Figure 3 Patterned application of fluorescent polythioether P1-1 with acid-base stimulus responsiveness.

[0034] Figure 4 Application of fluorescent polysulfide P1-1 as a replica material with acid-base stimulus responsiveness.

[0035] Figure 5 Food testing application of fluorescent polysulfide P1-1 with acid-base stimulus responsiveness.

[0036] Figure 6 Information encryption and storage applications of fluorescent polysulfide P1-1 with acid-base stimulus responsiveness. DETAILED DESCRIPTION

[0037] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0038] Example 1

[0039] Preparation of fluorescent polythioether P1-1 with acid-base stimulus responsiveness.

[0040]

[0041] Among them, monomer M1 was synthesized according to the synthesis method in the published literature (Green Chem., 2019, 21, 509.; J. Am. Chem. Soc. 2011, 133, 16901.); M2 was purchased from Anaiji Company. 38.2 mg (0.1 mmol) of monomer M1 and 25.0 mg (0.1 mmol) of monomer M2 were added to a 10 mL polymerization tube, and the vacuum was replaced with nitrogen three times. 0.4 mL of ultra-dry N, N-dimethylformamide (DMF) was injected with a syringe. After the monomer was completely dissolved, it was placed in an oil bath pot that was kept at 60°C and reacted for 4 hours. After the reaction was completed, 1 mL of chloroform was added, and the obtained polymer solution was added dropwise to 100 mL of vigorously stirred n-hexane, allowed to stand, filtered, and dried to obtain β-aldehyde polysulfide P1. The yield was 86%, the weight average molecular weight was 40260, and the molecular weight distribution was 2.74 (the molecular weight and molecular weight distribution were determined by gel permeation chromatography equipped with a refractive index detector. Tetrahydrofuran was used as the mobile phase, the flow rate was 1.0 mL / min, and linear monodistributed polystyrene was used as the standard for calibration). 1H NMR (500MHz, CDCl3), δ (TMS, ppm): 10.31, 9.32, 7.71, 7.51, 7.33, 7.18, 7.08, 7.01, 6.85, 6.63, 5.80, 5.71, 1.90, 1.80, 0.97, 0.60, 0.37, 0.15.

[0042] Add 3.16 mg (0.005 mmol) of β-formyl polysulfide P1 into a 10 mL polymerization tube, inject 0.5 mL of tetrahydrofuran with a syringe, and after the polymer is completely dissolved, inject 1 μl of hydrazine hydrate (0.00002 mmol), stir for 1 min to obtain P1-1 for standby use; (or after the reaction is completed, precipitate in vigorously stirred n-hexane, let stand, filter, and dry to obtain P1-1). 1 H NMR (500MHz, CDCl3), δ (TMS, ppm): 8.14, 7.52, 7.32, 7.15, 7.06, 6.52, 5.76, 5.37, 4.70, 3.04, 1.83, 1.24, 0.95, 0.55, 0.30.

[0043] The absorption and fluorescence properties of the acid-base responsive fluorescent polysulfide P1-1 were subsequently studied. The tetrahydrofuran solution of P1-1 was smeared on a quartz plate, and after the solvent evaporated, the UV-visible absorption spectrum was tested. Figure 1 It shows that P1-1 has almost no absorption in the visible light region above 525nm. After fumigation with HCl vapor, an obvious absorption peak appears at around 545nm. After fumigation with ammonia water, it basically returns to the original absorption position. The acid-base fumigation process is also accompanied by a color change from light yellow to brownish red. Moreover, after repeating the cycle 10 times, the absorption value has not dropped significantly, showing excellent fatigue resistance. Next, apply the tetrahydrofuran solution of P1-1 on the quartz plate, and after the solvent evaporates, test the fluorescence spectrum. Figure 1 As shown, initially the polymer film emits yellow-green fluorescence, with the corresponding emission peak at 535nm. After HCl vapor fumigation, the fluorescence color changes to rose red, with the corresponding emission peak red-shifted to 645nm. After fumigation with ammonia vapor, it basically returns to the initial fluorescence emission position. Figure 2 The fluorescence fatigue resistance of acid-base response was studied. The polymer film was fumigated with HCl vapor for 5s and then with ammonia vapor for 20s. The fluorescence intensity at 535nm and 645nm was monitored. After 10 repeated cycles, the fluorescence intensity did not decrease significantly, indicating that the polymer has good fatigue resistance. The reason for the above-mentioned changes in absorption and fluorescence spectra is due to the protonation and deprotonation of the nitrogen atom on the imine bond in P1-1.

[0044] Example 2

[0045] Preparation of fluorescent polythioether P2-1 with acid-base stimulus responsiveness.

[0046]

[0047] Monomer M3 was purchased from TCI. 38.2 mg (0.1 mmol) of monomer M1 and 14.2 mg (0.1 mmol) of monomer M3 were added to a 10 mL polymerization tube, and the vacuum was replaced with nitrogen for 3 times. 0.4 mL of ultra-dry DMF was injected with a syringe. After the monomer was completely dissolved, it was placed in an oil bath pot that was kept at 60°C and reacted for 4 hours. After the reaction was completed, 1 mL of chloroform was added, and the obtained polymer solution was added dropwise to 100 mL of vigorously stirred n-hexane, allowed to stand, filtered, and dried to obtain β-aldehyde polysulfide P2. The yield was 80%, the weight average molecular weight was 42390, and the molecular weight distribution was 2.64. 1 H NMR (500MHz, CDCl3), δ (TMS, ppm): 10.36, 9.33, 7.76, 7.58, 7.49, 6.93, 6.73, 6.58, 5.85.5.58, 1.99, 1.05, 0.65, 0.38.

[0048] Add 2.62 mg (0.005 mmol) of β-aldehyde polysulfide P2 into a 10 mL polymerization tube, inject 0.5 mL of tetrahydrofuran with a syringe, and after the polymer is completely dissolved, inject 1 μl of hydrazine hydrate (0.00002 mmol), stir for 1 min to obtain P2-1 for standby use; (alternatively, after the reaction is completed, precipitate in vigorously stirred n-hexane, let stand, filter, and dry to obtain P2-1).

[0049] Example 3

[0050] Preparation of fluorescent polythioether P3-1 with acid-base stimulus responsiveness.

[0051]

[0052] Monomer M4 was purchased from Anage Company. 38.2 mg (0.1 mmol) of monomer M1 and 14.2 mg (0.1 mmol) of monomer M4 were added to a 10 mL polymerization tube, vacuumed and replaced with nitrogen 3 times, 0.4 mL of ultra-dry DMF was injected with a syringe, and after the monomer was completely dissolved, it was placed in an oil bath pot that was kept at 60 ° C and reacted for 4 hours. After the reaction was completed, 1 mL of chloroform was added, and the obtained polymer solution was added dropwise to 100 mL of vigorously stirred n-hexane, allowed to stand, filtered, and dried to obtain β-aldehyde polysulfide P3. The yield was 78%, the weight average molecular weight was 34150, and the molecular weight distribution was 2.98. 1H NMR (500MHz, CDCl3), δ (TMS, ppm): 10.37, 10.21, 9.28, 7.73-7.10, 7.02-6.67, 5.79, 5.60, 1.88, 0.96, 0.62, 0.36, 0.10.

[0053] Add 2.62 mg (0.005 mmol) of β-aldehyde polysulfide P3 into a 10 mL polymerization tube, inject 0.5 mL of tetrahydrofuran with a syringe, and after the polymer is completely dissolved, inject 1 μl of hydrazine hydrate (0.00002 mmol), stir for 1 min to obtain P3-1 for standby use; (or after the reaction is completed, precipitate in vigorously stirred n-hexane, let stand, filter, and dry to obtain P3-1).

[0054] Example 4

[0055] Preparation of fluorescent polythioether P4-1 with acid-base stimulus responsiveness.

[0056]

[0057] Monomer M5 was synthesized according to the synthesis method in the published literature (Green Chem., 2019, 21, 509.; J. Am. Chem. Soc. 2011, 133, 16901.).

[0058] Add 29.8 mg (0.1 mmol) of monomer M5 and 25.0 mg (0.1 mmol) of monomer M2 to a 10 mL polymerization tube, evacuate and replace with nitrogen 3 times, inject 0.4 mL of ultra-dry DMF with a syringe, and after the monomers are completely dissolved, put them into an oil bath pot that has been kept at 60°C and react for 4 hours. After the reaction is completed, add 1 mL of chloroform, and drop the obtained polymer solution into 100 mL of vigorously stirred n-hexane, let it stand, filter, and dry to obtain β-aldehyde polysulfide P4. The yield is 84%, the weight average molecular weight is 22140, and the molecular weight distribution is 1.84. 1 H NMR (500MHz, CDCl3), δ (TMS, ppm): 10.35, 10.29, 9.33, 7.81, 7.75, 7.59, 7.53, 7. 51,7.38,7.21,7.18,7.00,6.83,6.66,5.79,5.66,1.53,1.39,1.35,1.20,1.18.

[0059] Add 2.74 mg (0.005 mmol) of β-formyl polysulfide P4 into a 10 mL polymerization tube, inject 0.5 mL of tetrahydrofuran with a syringe, and after the polymer is completely dissolved, inject 1 μl of hydrazine hydrate (0.00002 mmol), stir for 1 min to obtain P4-1 for standby use; (or after the reaction is completed, precipitate in vigorously stirred n-hexane, let stand, filter, and dry to obtain P4-1).

[0060] Example 5

[0061] Preparation of fluorescent polythioether P5-1 with acid-base stimulus responsiveness.

[0062]

[0063] Add 29.8 mg (0.1 mmol) of monomer M5 and 14.2 mg (0.1 mmol) of monomer M3 to a 10 mL polymerization tube, evacuate and replace with nitrogen 3 times, inject 0.4 mL of ultra-dry DMF with a syringe, and after the monomer is completely dissolved, put it into an oil bath pot that has been kept at 60°C and react for 4 hours. After the reaction is completed, add 1 mL of chloroform, and drop the obtained polymer solution into 100 mL of vigorously stirred n-hexane, let it stand, filter, and dry to obtain β-aldehyde polysulfide P5. The yield is 85%, the weight average molecular weight is 22100, and the molecular weight distribution is 1.79. 1 H NMR (500MHz, CDCl3), δ (TMS, ppm): 10.35, 10.18, 9.35, 9.25, 8.03, 7.76, 7. 61,7.48,7.33,6.97,6.73,6.58,5.80,5.53,1.53,1.49,1.42,1.36,1.32.

[0064] Add 2.20 mg (0.005 mmol) of β-formaldehyde polysulfide P5 into a 10 mL polymerization tube, inject 0.5 mL of tetrahydrofuran with a syringe, and after the polymer is completely dissolved, inject 1 μl of hydrazine hydrate (0.00002 mmol), stir for 1 min to obtain P5-1 for standby use; (or after the reaction is completed, precipitate in vigorously stirred n-hexane, let stand, filter, and dry to obtain P5-1).

[0065] Example 6

[0066] Preparation of fluorescent polythioether P6-1 with acid-base stimulus responsiveness.

[0067]

[0068] Add 29.8 mg (0.1 mmol) of monomer M5 and 14.2 mg (0.1 mmol) of monomer M4 to a 10 mL polymerization tube, evacuate and replace with nitrogen 3 times, inject 0.4 mL of ultra-dry DMF with a syringe, and after the monomers are completely dissolved, put it into an oil bath pot that has been kept at 60°C and react for 4 hours. After the reaction is completed, add 1 mL of chloroform, and drop the obtained polymer solution into 100 mL of vigorously stirred n-hexane, let it stand, filter, and dry to obtain β-aldehyde polysulfide P6. The yield is 88%, the weight average molecular weight is 10850, and the molecular weight distribution is 1.93. 1 H NMR (500MHz, CDCl3), δ (TMS, ppm): 10.36, 10.20, 9.30, 9.20, 7.67, 7.50, 7.05, 6.89, 6.67, 6.60, 5.75, 5.44, 1.61, 1.48, 1.40, 1.31, 1.18.

[0069] Add 2.20 mg (0.005 mmol) of β-formaldehyde polysulfide P6 into a 10 mL polymerization tube, inject 0.5 mL of tetrahydrofuran with a syringe, and after the polymer is completely dissolved, inject 1 μl of hydrazine hydrate (0.00002 mmol), stir for 1 min to obtain P6-1 for standby use; (or after the reaction is completed, precipitate in vigorously stirred n-hexane, let stand, filter, and dry to obtain P6-1).

[0070] Example 7

[0071] Application of acid-base stimuli-responsive fluorescent polysulfide in patterning and multicolor display.

[0072] The fluorescent polythioether with acid-base stimulus responsiveness in the present invention contains an imine bond, and the protonation and deprotonation of the imine bond nitrogen are used to adjust the electron donation (DA) effect in the polymer, thereby changing the luminescent color and intensity of the polymer, thereby realizing patterned applications. Figure 3 As shown, we take P1-1 as an example. First, the tetrahydrofuran solution of P1-1 is sprayed on the filter paper using a mold, and a light yellow "heart-shaped" pattern is obtained under a fluorescent lamp, and a yellow-green fluorescent "heart-shaped" pattern is obtained under ultraviolet light; then, the filter paper is fumigated with HCl vapor, and a brown-red "heart-shaped" pattern is obtained under a fluorescent lamp, and a rose-red fluorescent "heart-shaped" pattern is obtained under ultraviolet light; then, the filter paper is fumigated with NH3 vapor, and it returns to its original state. Moreover, by configuring polymer solutions of different concentrations or controlling the fumigation time of HCl and NH3 vapors, patterns with different apparent colors and fluorescent colors can be obtained to achieve multi-color display.

[0073] Example 8

[0074] Application of fluorescent polysulfide with acid-base stimulus responsiveness in copy materials.

[0075] The fluorescent polysulfide with acid-base stimulus responsiveness in the present invention is used as a copy material by utilizing the reversibility of apparent color and fluorescence change and good fatigue resistance. Figure 4 As shown, we take P1-1 as an example. First, the tetrahydrofuran solution of P1-1 is sprayed on the filter paper to obtain a filter paper with a light yellow appearance and yellow-green fluorescence under ultraviolet light. Then, after fumigation with the mold and HCl vapor, a brown-red "kitten" pattern appears under a fluorescent lamp, and a rose-red "kitten" pattern appears under an ultraviolet lamp. Next, the pattern information is erased after fumigation with NH3 vapor. The mold and HCl vapor are used to "write" again to obtain a "puppy" pattern; this cycle is repeated to achieve the erasable operation of information.

[0076] Example 9

[0077] Application of fluorescent polysulfide with acid-base stimulus responsiveness in food testing.

[0078] Food safety is directly related to human health, and strict control of food safety is of vital importance. In addition to ammonia causing color and fluorescence changes in protonated fluorescent polysulfide, biogenic amines produced during food spoilage can also play the same role. Taking P1-1 as an example, we first sprayed a tetrahydrofuran solution of P1-1 on the filter paper, and then fumigated it with HCl vapor to obtain a protonated polymer filter paper. The protonated polymer filter paper was placed in a sealed pomfret watch dish and stored at room temperature. Figure 5 As shown, at first, the protonated polymer filter paper was brown-red in appearance and emitted rose-red fluorescence under ultraviolet light, but as time went on, the protonated polymer filter paper was gradually deprotonated by the organic amines released by the pomfret, causing the filter paper to gradually turn light yellow and emit yellow-green fluorescence under ultraviolet light. In addition, the control group in which the protonated polymer filter paper was placed in a sealed pomfret watch dish and stored in a refrigerator found that the protonated polymer filter paper was still brown-red in appearance and emitted rose-red fluorescence under ultraviolet light. Thus, a food spoilage sensor with fluorescent polysulfide responsive to acid-base stimuli was established to sensitively detect ammonia and biogenic amines produced during food spoilage.

[0079] Example 10

[0080] Application of fluorescent polysulfide with acid-base stimulus responsiveness in information encryption and storage.

[0081] The acid-base responsiveness of fluorescent polysulfide can be used to change the color and intensity of polymer light emission, thereby realizing the application of polymer in information encryption and storage. Figure 6As shown, we take P1-1 as an example. First, use mold "8" to spray the tetrahydrofuran solution of P1-1 at position b on the filter paper, and spray the dye P7 with the same fluorescent color as P1-1 at position a. The two samples show a light yellow number "8" under fluorescent light and a yellow-green number under ultraviolet light. After fumigation with HCl vapor, the position where P1-1 is sprayed turns brown-red under fluorescent light and a rose-red fluorescent number "6" under ultraviolet light. Then, after fumigation with NH3 vapor, the original digital information will be restored, greatly improving the security of information encryption and the storage density of information.

[0082] The structural formula of P7 is as follows. After the action of HCl and NH3 vapor, the color does not change under the irradiation of fluorescent lamp and ultraviolet lamp.

[0083]

[0084] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A method for preparing a fluorescent polythioether having acid-base stimulus responsiveness, characterized in that: The method comprises the following preparation steps: The first step is to polymerize a dibasic acetylene aldehyde compound of formula (I) and a dibasic thiol compound of formula (II) in an organic solvent under an inert atmosphere or air. After the reaction is completed, the product is dissolved in an organic solvent and added to n-hexane for precipitation. The precipitate is collected and dried to a constant weight to obtain a β-aldehyde polysulfide of formula (III); The second step is to react the β-aldehyde polysulfide of the structure of formula (III) with hydrazine in an organic solvent under air atmosphere to obtain a fluorescent polysulfide solution with acid-base stimulus responsiveness; or the product is dissolved in an organic solvent, added to n-hexane for precipitation, the precipitate is collected, and dried to constant weight to obtain a fluorescent polysulfide with acid-base stimulus responsiveness of formula (IV); Wherein, n is an integer from 2 to 200, and R is an amino group; The R 1 Any one of the following chemical structural formulas, The R 2 Any one of the following chemical structural formulas: Wherein, m and h are integers of 1 to 15; * indicates the substitution position.

2. The method for preparing a fluorescent polythioether having acid-base stimulus responsiveness according to claim 1, characterized in that: The organic solvent in the first step and the second step is one or a mixture of two or more of tetrahydrofuran, dimethyl sulfoxide, N,N-dimethylformamide, dimethylacetamide and chloroform.

3. The method for preparing a fluorescent polythioether having acid-base stimulus responsiveness according to claim 1, characterized in that: The polymerization reaction temperature in the first step is 20-80° C., and the polymerization reaction time is 1-6 hours; the reaction temperature in the second step is room temperature, and the reaction time is 1 minute to 1 hour.

4. The method for preparing a fluorescent polythioether having acid-base stimulus responsiveness according to claim 1, characterized in that: The molar ratio of the dibasic acetylenic aldehyde compound to the dibasic thiol compound in the first step is 1:(1-1.1); the molar ratio of the β-aldehyde polysulfide to hydrazine in the second step is 1:(0.001-0.05); the concentration of the dibasic acetylenic aldehyde compound in the organic solvent in the first step is 0.05-0.5 mol / L, and the concentration of the β-aldehyde polysulfide in the organic solvent in the second step is 0.005-0.1 mol / L.

5. A fluorescent polythioether having acid-base stimulus responsiveness, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the fluorescent polysulfide responsive to acid-base stimulation as claimed in claim 5 in patterning and multicolor display.

7. Use of the fluorescent polysulfide responsive to acid-base stimulation as claimed in claim 5 in copying materials.

8. Use of the fluorescent polysulfide responsive to acid-base stimulation as claimed in claim 5 in food detection.

9. Use of the fluorescent polysulfide with acid-base stimulus responsiveness as claimed in claim 5 in information encryption and storage.

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