Isoquinoline micro-nanofiber membrane, preparation method and application thereof

Abstract

The application discloses a kind of isoquinoline micro-nanofiber membranes and its preparation method and application, the preparation raw material of the fiber membrane includes polymer and tetraphenyl ethene-isoquinoline compound, the structure general formula of the tetraphenyl ethene-isoquinoline compound is as follows:Ar represents isoquinoline.The fiber membrane of the present application has strong fluorescence, and the fluorescence color can present high contrast change before and after acid-base fumigation, and responds quickly to acid-base, and has wide application prospect in the field of acid-base detection and environmental monitoring.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluorescent materials, in particular to a isoquinoline micro-nano fiber membrane and a preparation method and application thereof. BACKGROUND

[0002] In the field of modern material science, micro-nano fiber membranes have shown great potential for application in various fields such as biomedical and environmental protection due to their unique physical and chemical properties, such as high specific surface area, excellent filtration performance, and excellent biocompatibility. In particular, in the field of advanced biological imaging and chemical sensing, micro-nano fiber membranes can achieve accurate detection, dynamic tracking, and high-definition imaging of specific substances due to their fluorescent properties. This unique fluorescent property is achieved by cleverly introducing compounds or groups with fluorescent properties into the fiber membrane, greatly expanding its application range in biological imaging and chemical analysis.

[0003] However, with the rapid development of science and technology and the increasing demand for material performance in the fields of biomedical, environmental protection, and energy storage, existing micro-nano fiber membranes have difficulty meeting the growing demand in some aspects. In particular, in application scenarios requiring rapid response to acid-base stimulation, it is particularly important to develop a new type of nano-fiber membrane with high sensitivity and rapid response to acid-base changes.

[0004] Therefore, in order to meet these growing demands, it is urgent to develop a new type of micro-nano fiber membrane. This membrane material not only inherits the advantages of traditional micro-nano fiber membranes, but also has a significant improvement in acid-base sensitivity, enabling it to quickly and accurately respond to changes in the external environment of acid-base, thereby exhibiting a broader application prospect in the fields of biomedical, environmental monitoring, and energy storage. SUMMARY

[0005] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes an isoquinoline micro-nano fiber membrane, which not only produces fluorescence, but also rapidly responds to different colors of fluorescence under acid-base stimulation.

[0006] The present application also proposes a preparation method of the above-mentioned fiber membrane.

[0007] The present application also proposes the application of the above-mentioned fiber membrane.

[0008] According to one aspect of the present application, an isoquinoline micro-nano fiber membrane is proposed, the preparation raw materials of the fiber membrane include a polymer and a tetraphenyl ethylene-isoquinoline compound, the structure general formula of the tetraphenyl ethylene-isoquinoline compound is as follows:

[0009] Ar represents isoquinoline.

[0010] According to a preferred embodiment of the present application, at least the following advantages are achieved: the fiber film of the present application has strong fluorescence, the fluorescence color shows high contrast change before and after acid-base fumigation, and the response to acid-base is rapid, which has wide application prospects in the fields of acid-base detection and environmental monitoring.

[0011] In some embodiments of the present application, the structure of the tetraphenylstyrene-isoquinoline compound is shown in one of the following formulas:

[0012]

[0013] In some embodiments of the present application, the polymer includes at least one of cellulose acetate (CA), polystyrene (PS), polyvinyl alcohol (PVA), and polylactic acid (PLA). The compound of the present application has good fluorescence stability in different polymer matrices.

[0014] In some embodiments of the present application, the mass ratio of the polymer to the tetraphenylstyrene-isoquinoline compound is 1:0.01-0.1. For example, 1:0.05.

[0015] In some embodiments of the present application, the preparation raw material further includes a solvent, and the solvent is selected from a mixed solution of DMF (N,N-dimethylformamide) and DCM (dichloromethane).

[0016] In some embodiments of the present application, the volume ratio of DMF to DCM is 1:1-3. For example, 1:2.

[0017] In some embodiments of the present application, the mass ratio of the tetraphenylstyrene-isoquinoline compound to the solvent is 1:175-185. For example, 1:179, 1:180, etc.

[0018] In some embodiments of the present application, silicone oil paper is used as a grounding collector in the preparation process of the fiber film.

[0019] According to another aspect of the present application, a preparation method of the above fiber film is provided, including the following steps:

[0020] The tetraphenylstyrene-isoquinoline compound and the polymer are weighed and dissolved in a solvent to prepare an electrospinning solution. The solution is loaded into a syringe, and the solution is extruded from a spinneret at a speed of 0.8-1.2 mL / h (preferably 1.0 mL / h) under the action of high-voltage electrostatic force to form a fiber. The spinning voltage is 15-20 kV (preferably 17 kV), and the working distance is 11-15 cm (preferably 13 cm).

[0021] The general structure of the tetraphenylstyrene-isoquinoline compound is as follows:

[0022] Ar represents isoquinoline.

[0023] In some embodiments of the present application, a silicone oil paper is used as a grounding collector in the preparation of the fiber membrane.

[0024] According to another aspect of the present application, the above fiber membrane is applied in the field of detection or anti-counterfeiting.

[0025] In some embodiments of the present application, the detection includes at least one of the following detection contents:

[0026] 1) acidic substances;

[0027] 2) basic substances.

[0028] In some embodiments of the present application, the detection includes the following steps: applying the detection content to the fiber membrane, irradiating the compound by a UV light source as an excitation light source, and observing the fluorescence change.

[0029] In some embodiments of the present application, the detection content can be applied to the surface or inside of the product to be detected without complex operations such as photo-induced polymerization, and the detection method of the present application is simple and efficient, can realize batch automatic detection, and has good industrial application prospect.

[0030] In some preferred embodiments of the present application, the application includes at least one of coating, dipping, and fumigation. The detection content is applied to the surface of the product to be detected by coating, dipping, or fumigation, and the operation is simple.

[0031] In some preferred embodiments of the present application, the wavelength of the UV light source is 320-405 nm; preferably 345-385 nm; and more preferably 365 nm.

[0032] According to the application of one preferred embodiment of the present application, at least the following beneficial effects are achieved: the compound of the present application has strong fluorescence, and after being prepared into a fiber membrane, it has a larger specific surface area, so that it responds more quickly to external stimuli. The fiber membrane of the present application responds quickly to acid and base, has good reversibility to acid fumigation, can be repeatedly used, and has good industrial application prospect.

[0033] Other features and advantages of the present application will be set forth in the specification, and in part will become apparent from the specification, or can be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0034] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the accompanying drawings, in which:

[0035] Figure 1 SEM image of the nanofiber membrane prepared in Example 1 of the present application.

[0036] Figure 2 Optical and inverted fluorescence microscope images of the PLA-Iso-TPECN3Qu compound / micro-nanofiber membrane prepared in Example 1 of the present application with different contents: a) daylight lamp image; b) ultraviolet lamp image; c) inverted fluorescence microscope image.

[0037] Figure 3 PL spectra of the PLA-Iso-TPECN3Qu micro-nanofiber membrane prepared in Example 1 of the present application under external stimuli: m represents the initial thin film; m-HCl represents the thin film after m acid fumigation; m-HCl-NH3 represents the thin film after m-HCl thin film alkali fumigation.

[0038] Figure 4 Fluorescence images (365 nm) of the PLA-Iso-TPECN3Qu micro-nanofiber membrane prepared in Example 1 of the present application under external stimuli.

[0039] Figure 5 Fluorescence emission wavelength changes and fluorescence images of the PLA-Iso-TPECN3Qu micro-nanofiber membrane prepared in Example 1 of the present application after acid and alkali stimulation for 10 cycles.

[0040] Figure 6 Microstructure images of the PLA-ISO-TPECN4Qu fiber membrane prepared in Example 4 of the present application at 1.50 kX a) and 5.00 kX b) magnifications.

[0041] Figure 7 Microstructure images of the PLA-ISO-TPECN5Qu fiber membrane prepared in Example 5 of the present application at 1.50 kX a) and 5.00 kX b) magnifications.

[0042] Figure 8 Microstructure images of the PLA-ISO-TPECN8Qu fiber membrane prepared in Example 6 of the present application at 1.50 kX a) and 5.00 kX b) magnifications.

[0043] Figure 9 Acid and alkali stimulation test results of the fiber membranes prepared in Examples 4-6. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the concept and technical effects of the present invention in conjunction with embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the embodiments are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available. Unless otherwise specified, the same parameter value is the same in all embodiments. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0045] In the description of this invention, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0046] The procurement information for some of the raw materials used in the following embodiments and Comparative Example 1 is shown in Table 1 below:

[0047] Table 1

[0048]

[0049] The instrument information used in the following embodiments and Comparative Example 1 is shown in Table 2 below:

[0050] Table 2

[0051]

[0052] The methods and main parameters used in the testing and characterization process are as follows:

[0053] compound 1 H-NMR and 13 C-NMR was measured using a Bruker AVANCE NEO 500 spectrometer with deuterated chloroform as solvent and tetramethylsilane (TMS) as internal standard to determine the chemical structure of the compound.

[0054] Fluorescence spectroscopy and UV-Vis absorption spectroscopy are used to analyze the photophysical properties of compounds. For AIE performance testing, the excitation and emission slits for fluorescence spectra are 10 nm and 15 nm, respectively, with the remaining slits at 3 nm and 5 nm.

[0055] X-ray diffractometer with Cu Kα (λ = 0.1541 nm) as light source, test voltage 40 kV, 40 mA, used to characterize the aggregate state structure of the compound.

[0056] Steady-state / transient combined fluorescence spectrometer and calibrated integrating sphere test the fluorescence quantum efficiency of the compound.

[0057] Scanning electron microscope is used to observe the microstructure of the fiber membrane, and the operating voltage is 15 kV.

[0058] The specific synthesis process of TPECN is as follows (referring to the literature Zhang X, Zhang X, Yang B, et al. Facile preparation of water dispersible red fluorescent organic nanoparticles and their cell imaging applications [J]. Tetrahedron, 2014, 70 (22): 3553-3559. Preparation):

[0059] Dissolve 1-bromo-1,2,2-triphenyl ethylene (1.74 g, 5.2 mmol) and 4-(cyanoethyl) phenylboronic acid (1.00 g, 6.2 mmol) in a mixture of toluene (40 mL), Aliquat 336 (methyltrioctylammonium chloride, 10 drops) and 2M aqueous potassium carbonate solution (10 ml). Stir under argon at room temperature for 0.5 h, add Pd(PPh3)4(0.010 g, 8.70*10 -3 mmol), after heating to 90℃ for 24 h, pour the mixture into water, extract with ethyl acetate three times. Dry the organic layer over anhydrous sodium sulfate. After removing the solvent under reduced pressure, the residue is chromatographed on a silica gel column with petroleum ether / CH2Cl2(v / v 3:1) as eluent to obtain intermediate 1 (1.30 g, yield 68%).

[0060] The specific process of preparing tetraphenyl ethylene-isoquinoline compound Iso-TPECN3Qu is as follows: TPECN (1 g, 2.6 mmol) is added to a three-necked flask, 30 mL of anhydrous ethanol is added, and it is dissolved under magnetic stirring. After complete dissolution, nitrogen is introduced, isoquinoline-3-carboxaldehyde (0.41 g, 2.6 mmol) is added, the temperature is raised to 80℃, and an appropriate amount of catalyst TBAH is added, and the reaction is carried out for 24 h. After the reaction is completed, filtration is performed, and the filter residue is washed with ethanol repeatedly for 3 times to obtain a light yellow solid powder (1.3 g, 80%). 1H NMR (500 MHz, CDC13) δ 9.33 (s, 1H), 8.23 (s, 1H), 8.01 (dd, J = 8.3, 1.2 Hz, 1H), 7.91 (dd, J = 8.3, 1.1 Hz, 1H), 7.78 - 7.64 (m, 3H), 7.56 - 7.50 (m, 2H), 7.17 - 7.02 (m, 17H). 13 C NMR (500 MHz, CDC13) δ 152.68, 146.13, 145.33, 143.44, 143.38, 143.27, 142.09, 140.58, 139.92, 135.81, 132.23, 132.05, 131.39, 131.32, 131.04, 128.69, 128.56, 127.93, 127.85, 127.80, 127.71, 127.52, 126.87, 126.72, 126.67, 125.55, 121.81, 117.83, 113.30.

[0061] Synthesis of ISO-TPECN4Qu: Under nitrogen, TPECN (1 g, 2.6 mmol) and isoquinoline-4-carboxaldehyde (0.4086 g, 2.6 mmol) were added and allowed to dissolve completely, then an appropriate amount of catalyst tetrabutylammonium hydroxide (0.49 g, 0.0019 mmol) was added to the reaction solution. After the reaction was completed, negative pressure filtration was performed, and ethanol was used to rinse three times during the process. After the filtration was completed, the filter residue was placed in an oven for drying, and 1.30 g of yellow solid powder was obtained (yield 83%).

[0062] 1 H NMR (500 MHz, CDC13) δ 9.33 (s, 1H), 8.23 (s, 1H), 8.01 (dd, J = 8.3, 1.2 Hz, 1H), 7.91 (dd, J = 8.3, 1.1 Hz, 1H), 7.78 - 7.64 (m, 3H), 7.56 - 7.50 (m, 2H), 7.17 - 7.02 (m, 17H). 13C NMR (500 MHz, CDC13) δ 154.37, 145.91, 143.44, 143.35, 143.04, 142.37, 139.85, 135.87, 133.99, 132.30, 131.48, 131.45, 131.41, 128.69, 128.16, 128.10, 128.04, 128.01, 127.85, 127.04, 126.90, 126.86, 125.74, 122.89, 117.21, 117.13.C 38 H 27 ESI+ HRMS m / z calcd for N2 511.2183 [M+H], found 511.2183 [M+H].

[0063] Synthesis of ISO-TPECN5Qu: Method and similar to the synthesis of ISO-TPECN4Qu described above, where the starting material added was the isomer of isoquinoline-4-carboxaldehyde, isoquinoline-5-carboxaldehyde, resulted in 1.20 g of light yellow solid, yield 71%.

[0064] 1 H NMR (500 MHz, CDC13) δ 9.31 (d, J = 0.9 Hz, 1H), 8.61 (d, J = 6.0 Hz, 1H), 8.30 (dd, J = 7.3, 1.1 Hz, 1H), 8.12 - 8.04 (m, 2H), 7.79 - 7.68 (m, 2H), 7.55 - 7.49 (m, 2H), 7.18 - 7.03 (m, 17H). 13 C NMR (500 MHz, CDC13) δ 153.47, 145.89, 144.15, 143.45, 143.35, 142.38, 139.84, 137.20, 134.44, 132.32, 131.59, 131.47, 131.46, 131.40, 130.98, 130.42, 130.10, 128.71, 128.09, 128.01, 127.85, 127.23, 127.03, 126.90, 126.86, 125.67, 117.47, 116.48, 116.32, 1.16.C 38 H 27 ESI+ HRMS m / z calcd for N2 512.2181 [M+H], found 512.2181 [M+H].

[0065] Synthesis of ISO-TPECN8Qu: The procedure was similar to the synthesis of ISO-TPECN4Qu described above, except that the isomeric isoquinoline-8-carboxaldehyde was used instead of isoquinoline-4-carboxaldehyde. The resulting 1.10 g of light yellow solid was obtained in 78% yield.

[0066] 1 H NMR (500 MHz, CDC13) δ 9.44 (d, J = 1.0 Hz, 1H), 8.64 (d, J = 5.6 Hz, 1H), 8.26 (s, 1H), 8.10 (dd, J = 7.2, 1.1 Hz, 1H), 7.91 (d, J = 8.3 Hz, 1H), 7.77 (dd, J = 8.3, 7.2 Hz, 1H), 7.72 (dd, J = 5.8, 0.9 Hz, 1H), 7.56 - 7.51 (m, 2H), 7.21 - 7.02 (m, 17H). 13 C NMR (500 MHz, CDC13) δ 148.53, 145.99, 144.02, 143.45, 143.43, 143.33, 142.41, 139.85, 137.20, 136.17, 132.35, 132.17, 131.48, 131.45, 131.41, 130.23, 129.01, 128.19, 128.10, 128.02, 127.84, 127.08, 126.90, 126.85, 126.59, 125.71, 121.17, 117.37, 117.07.C 38 H 27 ESI+ HRMS m / z calcd for N2 511.2177 [M+H], found 511.2177 [M+H].

[0067] Example 1

[0068] In this example, an isoquinoline fiber film was prepared. 0.05 g of tetraphenyl ethene-isoquinoline compound Iso-TPECN3Qu and 1 g of polymer (PLA) were weighed and dissolved in 8.95 g of a mixed solution of DMF / DCM (v / v = 1 / 2) to prepare an electrospinning solution. Then, the solution was loaded into a 10 mL syringe, and the solution was extruded from the spinneret at a speed of 1 mL / h to form a fiber under the action of high-voltage static electricity. The spinning voltage was 17 kV, the working distance was 13 cm, and a silicone oil paper was used as a grounded collector.

[0069] Example 2

[0070] An isoquinoline fiber film was prepared in this example. 0.05 g of a tetraphenyl ethene-isoquinoline compound Iso-TPECN3Qu and 1 g of a polymer (PS) were dissolved in 8.95 g of a mixed solution of DMF / DCM (v / v=1 / 2) to prepare an electrospinning solution. Then, the solution was loaded into a 10 mL syringe, and the spinneret was extruded at a speed of 1 mL / h to form a fiber under the action of high-voltage electrostatic. The spinning voltage was 17 kV, the working distance was 13 cm, and a silicone oil paper was used as a grounded collector.

[0071] Example 3

[0072] An isoquinoline fiber film was prepared in this example. 0.05 g of a tetraphenyl ethene-isoquinoline compound Iso-TPECN3Qu and 1 g of a polymer (PS) were dissolved in 8.95 g of a mixed solution of DMF / DCM (v / v=1 / 2) to prepare an electrospinning solution. Then, the solution was loaded into a 10 mL syringe, and the spinneret was extruded at a speed of 1 mL / h to form a fiber under the action of high-voltage electrostatic. The spinning voltage was 17 kV, the working distance was 13 cm, and a silicone oil paper was used as a grounded collector.

[0073] Example 4

[0074] An isoquinoline fiber film was prepared in this example, which was different from Example 1 in that the tetraphenyl ethene-isoquinoline compound was Iso-TPECN4Qu.

[0075] Example 5

[0076] An isoquinoline fiber film was prepared in this example, which was different from Example 1 in that the tetraphenyl ethene-isoquinoline compound was Iso-TPECN5Qu.

[0077] Example 6

[0078] An isoquinoline fiber film was prepared in this example, which was different from Example 1 in that the tetraphenyl ethene-isoquinoline compound was Iso-TPECN8Qu.

[0079] Comparative Example 1

[0080] A fluorescent material was provided in this example, which was 0.05 g of an isoquinoline compound Iso-TPECN3Qu.

[0081] Comparative Example 2

[0082] A fluorescent material was provided in this example, which was 0.05 g of an isoquinoline compound Iso-TPECN4Qu.

[0083] Comparative Example 3

[0084] The example provides a fluorescent material which is 0.05 g isoquinoline compound Iso-TPECN5Qu.

[0085] Comparative Example 4

[0086] The example provides a fluorescent material which is 0.05 g isoquinoline compound Iso-TPECN8Qu.

[0087] Test Example

[0088] The test example tests the acid-base stimulus response performance of the fiber membranes prepared in the examples and the fluorescent materials of the comparative examples. The specific operation is as follows:

[0089] The example and comparative example samples are subjected to fumigation treatment by acid vapor (HCl) and base vapor (NH3) under the same conditions, and the response time and fluorescence change are tested. At 25°C, a small amount of hydrochloric acid solution or ammonia water is placed in a closed desiccator (hydrochloric acid aqueous solution is used, and the content of HCl is 36%-38%; the base solution uses ammonia water, and the content of NH3 is 25%-28%. 10-15 ml of hydrochloric acid or ammonia water solution is placed in a desiccator with a volume of about 6.28 liters, and the container is filled with acid or base vapor at room temperature (about 25°C) for about 30 minutes), after the acid vapor and ammonia vapor fill the desiccator, the sample is placed in a petri dish and placed in the desiccator, a 365 nm ultraviolet lamp is used to observe the fluorescence change, and the response time is recorded.

[0090] It is found that the Iso-TPECN3Qu compound needs a relatively long time to test the acid-base stimulus in the powder state, because the acid vapor first contacts the outermost layer of the powder, and it takes time to diffuse to the inner layer.

[0091] The electron microscope characterization results of the PLA-Iso-TPECN3Qu fiber membrane are as shown in Figure 1 It can be seen from the figure that the surface of the prepared composite fiber membrane is uniform and smooth, and no granular aggregates are observed, indicating that the Iso-TPECN3Qu compound has good compatibility with PLA, and the addition of the Iso-TPECN3Qu compound does not affect the spinning performance of PLA. At the same time, by preparing micro-nano fiber membranes by compounding the Iso-TPECN3Qu compound with PS and other polymers, the fluorescence stability of the Iso-TPECN3Qu compound in different polymers is explored, and it is found that they all have good fluorescence stability. At the same time, by compounding the Iso-TPECN3Qu compound with different mass of PLA to prepare micro-nano fiber membranes, the effect of the content of the Iso-TPECN3Qu compound on the fluorescence performance of the micro-nano fiber membranes is explored. The results are as shown in Figure 2As shown, with the content of Iso-TPECN3Qu compound increasing from 1% to 10% (mass ratio of Iso-TPECN3Qu to PLA, small molecule mass: polymer mass = 0.01-0.1:1), the fluorescence color gradually red-shifts from blue at 1% to green at 10%. The experimental results show that the content of Iso-TPECN3Qu compound is proportional to the fluorescence performance of the micro-nano fiber film.

[0092] The spun PLA-Iso-TPECNnQu micro-nano fiber film sample is named as ISO-TPECNnQu-x. It is placed in a closed HCl for 10s acid fumigation. The acid fumigated sample is cut into two uniform parts, and the sample is named as ISO-TPECNnQu-x-h and ISO-TPECNnQu-x-h-n, respectively. Then, ISO-TPECNnQu-x-h-n is placed in a closed ammonia steam for 10s fumigation, and the obtained sample is called ISO-TPECNnQu-x-h-n. The photos of ISO-TPECNnQu-x, ISO-TPECNnQu-x-h and ISO-TPECNnQu-x-h-n are taken under ultraviolet light, respectively, and the fluorescence spectrum test is performed on the three samples.

[0093] During the acid stimulation response experiment, the fluorescence color of the PLA-Iso-TPECN3Qu micro-nano fiber film changes from blue to light green (as shown in the results of Figure 3 ) after being fumigated with HCl steam for about 3s. The maximum emission wavelength of fluorescence also red-shifts from 499nm to 559nm, with a red shift of 60nm (as shown in the results of Figure 4 ). Using NH3 steam to deprotonate it, the wavelength returns to the initial state. The shift of fluorescence emission wavelength before and after acid-base stimulation response is not significantly attenuated after 10 cycles (as shown in the results of Figure 5 ), which indicates that the acid-base stimulation response performance of the PLA-Iso-TPECN3Qu micro-nano fiber film has good stability and repeatability. The experimental results show that the larger surface area of the electrospun micro-nano fiber significantly enhances the HCl transmission ability. This reversible acid-base stimulation response micro-nano film can be used in acid detection and anti-counterfeiting fields.

[0094] The effects of other embodiments are similar to those of Embodiment 1. To avoid redundancy, they are not shown one by one.

[0095] The initial powder of Iso-TPECN3Qu in Comparative Example 1 was subjected to hydrochloric acid vapor fumigation, and its fluorescence color changed obviously: from the initial blue fluorescence to green fluorescence, and the emission wavelength also red-shifted from the initial 463 nm to 510 nm, which indicated that the solid powder of Iso-TPECN3Qu had obvious acid stimulation response. Interestingly, when the sample was deprotonated after ammonia vapor fumigation after acid fumigation, it was found that the fluorescence maximum emission wavelength further red-shifted (536 nm) and did not completely recover to the initial state. And its response time needs more than 10 s.

[0096] The SEM images of the fiber membranes prepared in Examples 4-6 are shown in Figures 6-8 From the images, it can be seen that the cross sections of the fiber membranes prepared by the scheme of the application are nearly circular, and the longitudinal sections of the fibers are smooth. In addition, the SEM images of the fiber membranes prepared by the examples of the application and the pure polymer fiber membranes were compared, and the results showed that there was no obvious difference between the fiber membranes prepared by the scheme of the application and the pure polymer membranes, and they all had similar hetero-fiber silk structure, therefore, the presence of the tetraphenyl ethene-isoquinoline compound (ISO-TPECNnQu) does not affect the fiber forming performance of PLA.

[0097] The acid-base stimulation test of the fiber membranes prepared in Examples 4-6 is shown in Figure 9 From the images, it can be seen that the cross sections of the fiber membranes prepared by the scheme of the application are nearly circular, and the longitudinal sections of the fibers are smooth. In addition, the SEM images of the fiber membranes prepared by the examples of the application and the pure polymer fiber membranes were compared, and the results showed that there was no obvious difference between the fiber membranes prepared by the scheme of the application and the pure polymer membranes, and they all had similar hetero-fiber silk structure, therefore, the presence of the tetraphenyl ethene-isoquinoline compound (ISO-TPECNnQu) does not affect the fiber forming performance of PLA. Figure 9 From the left upper image in Figure 9 , it can be seen that the original PLA-ISO-TPECN5Qu micro-nano fiber membrane red-shifted 19 nm from dark green fluorescence (484 nm) to bright green fluorescence (511 nm) under 365 nm ultraviolet lamp irradiation, indicating that it had certain reversible acid-induced color change performance, and the reversible acid-induced color change performance was more obvious than that of PLA-ISO-TPECN4Qu. Figure 9 From the lower image in Figure 9 , it can be seen that the original PLA-ISO-TPECN8Qu micro-nano fiber membrane red-shifted 43 nm from dark green fluorescence (490 nm) to dark yellow fluorescence (533 nm) under 365 nm ultraviolet lamp irradiation, indicating that it had certain reversible acid-induced color change performance, and the reversible acid-induced color change performance was more obvious than that of PLA-ISO-TPECN5Qu.

[0098] The acid-induced color change performance measured in Examples 4-6 and Comparative Examples 2-4 is shown in Table 3.

[0099] Table 3

[0100]

[0101]

[0102] From the above table, the acid and base fumigation time of PLA-ISO-TPECNnQu is lower than that of ISO-TPECNnQu because the specific surface area of the micro-nano fiber membrane is large, the detection time is short, and the response speed is fast, so it has obvious reversible acid-induced discoloration performance in a short time. Among the three PLA-ISO-TPECNnQu micro-nano fiber membranes, the acid-induced discoloration performance: ISO-TPECN8Qu is red-shifted from dark green fluorescence (490nm) to dark yellow fluorescence (533nm), ISO-TPECN5Qu is red-shifted from dark green fluorescence (484nm) to bright green fluorescence (511nm), and ISO-TPECN4Qu is red-shifted from blue-green fluorescence (475nm) to yellow-green fluorescence (486nm). ISO-TPECN8Qu has the most obvious red shift, followed by ISO-TPECN5Qu, and all of them can be restored to or close to the state before acid fumigation by ammonia fumigation. All three compounds have good reversible acid-induced discoloration performance.

[0103] In summary, the PLA-Iso-TPECNnQu micro-nano fiber membrane prepared by compounding isoquinoline derivatives and polylactic acid shows the acid and base-induced discoloration properties of the compound itself. However, unlike the powder state, the acid fumigation film of the nano fiber membrane has good reversible performance, and its response time is greatly improved compared to the powder state of the compound.

[0104] The above has made a detailed description of the embodiments of the present application, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge range of ordinary skilled persons in the art without departing from the purpose of the present application.

Claims

1. An isoquinoline micro- or nano-fiber membrane, characterized by: The raw material for preparing the fiber membrane comprises a polymer and a tetraphenyl ethylene-isoquinoline compound, the structural formula of the tetraphenyl ethylene-isoquinoline compound is shown in one of the following formulas: 。 2. The isoquinoline micro- or nano-fiber membrane according to claim 1, characterized in that: The polymer comprises at least one of cellulose acetate, polystyrene, polyvinyl alcohol and polylactic acid.

3. The isoquinoline micro- or nano-fiber membrane according to claim 1, characterized in that: The mass ratio of the polymer to the tetraphenyl ethylene-isoquinoline compound is 1:0.01-0.

1.

4. The isoquinoline micro- or nano-fiber membrane according to claim 1, characterized in that: The raw material further comprises a solvent selected from a mixed solution of DMF and DCM.

5. A method for producing a fibrous membrane, characterized by: The method comprises the following steps: The tetraphenyl ethylene-isoquinoline compound and the polymer are weighed and dissolved in a solvent to prepare an electrospinning solution, the solution is loaded into a syringe, and the solution is extruded from a spinneret at a speed of 0.8-1.2 mL / h to form a fiber under the action of high-voltage static electricity; wherein the spinning voltage is 15-20 kV, and the working distance is 11-15 cm. The structural formula of the tetraphenyl ethylene-isoquinoline compound is shown in one of the following formulas: 。 6. The fiber membrane according to any one of claims 1-4 is applied in the field of detection or anti-counterfeiting.

7. Use according to claim 6, characterized in that: The detection comprises at least one of the following detection contents: 1) acidic substances; 2) basic substances.

8. Use according to claim 7, characterized in that: The detection comprises the following steps: applying the detection content to the fiber membrane, irradiating the compound by using an ultraviolet light source as an excitation light source, and observing the fluorescence change.

9. Use according to claim 8, characterized in that: The application comprises at least one of coating, dipping and fumigation.

10. Use according to claim 8, characterized in that: The wavelength of the ultraviolet light source is 320-405 nm.

11. Use according to claim 8, characterized in that: The wavelength of the ultraviolet light source is 345-385 nm.

12. The use according to claim 8, characterized in that: The wavelength of the ultraviolet light source is 365 nm.

Images