Hydrophilic functional layer specific coloring agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of dyeing characterization of surface functional layers of composite materials, in particular to a hydrophilic functional layer specific coloring agent and a preparation method and application thereof, and the hydrophilic functional layer specific coloring agent is composed of 0.01%-0.5% by mass of xanthene fluorescent dye, 0.1%-5% by mass of hydrophilic polymer additive and the balance of water. Wherein the xanthene fluorescent dye is 9-(2-carboxyl phenyl)-3, 6-bis (diethylamino) xanthyleione chloride, and the structural formula of the xanthene fluorescent dye is shown in the description. After a hydrophilic film is dyed by the specific dyeing agent for the hydrophilic functional layer, an extremely high color contrast can be presented between the hydrophilic functional layer and a base material layer, and the background is clean and clear. For the defects such as uneven coating, microcracks and pinholes which cannot be recognized by conventional visual observation and are in the order of nanometer to micrometer, the coloring agent can clearly expose the defects through the difference of local color depth or fluorescence intensity, and visual precision diagnosis of the quality of the hydrophilic functional layer is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dyeing characterization of composite material surface functional layer, in particular to a hydrophilic functional layer specific dyeing agent and a preparation method and application thereof. BACKGROUND

[0002] Composite film materials with a "substrate layer-functional layer" are key materials in modern industry, and the physical and chemical properties (such as integrity, uniformity, thickness, etc.) of the functional layer directly determine the performance of the final product. For example, composite hydrophilic films widely used in the fields of biosensors, microfluidic chips, etc., the surface hydrophilic functional layer is responsible for the directional transport of liquid, and any microscopic coating defects of the functional layer will lead to product functional failure. However, since the functional layer is usually transparent or light-colored microporous structure, its morphology and coverage state are difficult to be effectively observed and evaluated by conventional optical methods.

[0003] Currently, the characterization of such transparent or weak contrast functional coating is highly dependent on professional instruments, such as contact angle measuring instrument, electron microscope or white light interferometer, etc. Although these methods are accurate, they have problems such as expensive equipment, complex operation, tedious sample preparation and difficulty in realizing rapid and global screening on the production line. Therefore, developing a technology that can realize rapid and high-contrast visualization of specific functional layer through simple dyeing reaction is an urgent technical problem to be solved in the field.

[0004] However, the core of realizing rapid and high-contrast visualization of specific functional layer is to seek a functional dye that can meet the specific needs. The ideal dyeing agent needs to have the following characteristics: (1) it can selectively physically and chemically bind to specific chemical components in the hydrophilic functional layer, and hardly stains the hydrophobic polymer substrate; (2) even in a small amount, it can produce a strong enough color signal to be identified by visual observation or simple optical equipment, so as to clearly outline the boundary and defects of the functional layer; (3) the dyeing agent needs to effectively penetrate and adhere to the porous structure of the functional layer, and is not easy to migrate or fade, ensuring the stability of the evaluation results; (4) the dyeing process should not significantly change the inherent physical and chemical properties of the functional layer, especially its hydrophilicity, pore structure and other key parameters.

[0005] There is no dye and dyeing method in the prior art that can meet the above requirements to dye the hydrophilic functional layer.

[0006] In view of this, the present application is proposed. SUMMARY

[0007] The present application aims to provide a hydrophilic functional layer specific dyeing agent, a preparation method and application thereof.

[0008] In a first aspect, the present application provides a hydrophilic functional layer specific dyeing agent, which is composed of 0.01%-0.5% of xanthene fluorescent dye and 0.1%-5% of hydrophilic polymer auxiliary agent, and the rest is water. The xanthene fluorescent dye is 9-(2-carboxyphenyl)-3,6-bis(diethylamino)xanthone chloride.

[0009] The hydrophilic functional layer specific dyeing agent of the present application is composed of 9-(2-carboxyphenyl)-3,6-bis(diethylamino)xanthone chloride and hydrophilic polymer auxiliary agent. In the dyeing stage, when the cationic fluorescent dye of 9-(2-carboxyphenyl)-3,6-bis(diethylamino)xanthone chloride contacts with the hydrophilic functional layer rich in anionic groups such as carboxyl and sulfonate, strong and rapid electrostatic attraction occurs first, and under this electrostatic action, the dye molecules are preferentially and firmly combined on the negatively charged hydrophilic functional layer. Further, on the basis of the initial electrostatic combination, the xanthene ring large pi conjugated system of the dye molecule core can occur "pi-pi stacking" with the aromatic ring or other conjugated structure in the polymer chain of the hydrophilic layer, which can further "lock" the dye molecules on the polymer skeleton from multiple sites. The hydrophilic polymer auxiliary agent not only guarantees the long-term stability and uniformity of the dyeing agent working solution, but also guides the dye molecules into the coating interior and combines with deeper anionic sites, thereby more truly reflecting the three-dimensional integrity of the entire functional layer and realizing uniform, moderate and consistent dyeing. In the elution stage, due to the strong "pi-pi stacking" secondary anchoring effect between the hydrophilic functional layer and the dye, and only weak physical adsorption between the substrate layer and the dye, in the acidic environment, this weak binding force is completely destroyed, so that the adsorbed dye molecules rapidly dissociate and dissolve in the eluent. Therefore, after the hydrophilic membrane is dyed and eluted by the hydrophilic functional layer specific dyeing agent of the present application, the hydrophilic functional layer and the substrate layer can exhibit extremely high color contrast, with a clean and clear background, ensuring the accuracy of observation and judgment.

[0010] Preferably, the hydrophilic polymer auxiliary agent includes any one of polyethylene glycol, copolymerized povidone, polyvinylpyrrolidone and polyvinyl alcohol. Further preferably, the hydrophilic polymer auxiliary agent is polyethylene glycol.

[0011] As a preferred embodiment of this technical solution, in the hydrophilic functional layer specific staining agent, the mass concentration of 9-(2-carboxyphenyl)-3,6-bis(diethylamino) in tonne chloride is 0.05%-0.3%, and preferably 0.1%.

[0012] As a preferred embodiment of this technical solution, in the hydrophilic functional layer specific dyeing agent, the mass concentration of the hydrophilic polymeric auxiliary agent is 0.5%-2%, and preferably 1%.

[0013] Secondly, the present invention also provides a method for preparing the above-mentioned hydrophilic functional layer specific staining agent, specifically including the following steps: A hydrophilic polymeric auxiliaries are dissolved in water to prepare a polymeric aqueous solution; Anthracene fluorescent dyes are added to an aqueous solution of a polymer and stirred until completely dissolved to obtain a hydrophilic functional layer-specific staining agent.

[0014] This invention utilizes a hydrophilic polymeric auxiliary agent to first prepare a polymeric solution, providing a stable "matrix" for the subsequent dispersion of dye molecules. This effectively prevents the aggregation and precipitation of dye molecules, significantly extending the shelf life of the working solution. Furthermore, the stepwise preparation method ensures that the dye molecules are uniformly dispersed at the molecular level in the solution. As a result, during the subsequent dyeing process, a dyeing area with clear boundaries and uniform color can be formed on the hydrophilic functional layer, effectively avoiding defects such as spots and streaks, and greatly improving the accuracy and reliability of the detection results.

[0015] In addition, to further improve the stability of the hydrophilic functional layer specific staining agent, it should be stored at room temperature for more than 4 hours after the staining agent is prepared before use.

[0016] Thirdly, the present invention also provides the application of the above-mentioned hydrophilic functional layer-specific dye in the quality control of the hydrophilic functional layer on the hydrophilic membrane, which should also fall within the protection scope of the present invention, specifically including the following steps: S1. Remove the protective layer of the hydrophilic membrane and immerse it in a specific staining agent for the hydrophilic functional layer, and perform staining in a water bath at 40-60℃. S2. The dyed hydrophilic membrane is cured to obtain a dyed and cured hydrophilic membrane; S3. Immerse the dyed and cured hydrophilic membrane in an acidic solution for decolorization. S4. Observe the staining on the surface of the hydrophilic membrane. The stained area represents the hydrophilic functional layer, and the unstained area represents the absence of the hydrophilic functional layer or the substrate layer.

[0017] This invention exhibits extremely high sensitivity to microscopic defects in hydrophilic functional layers. For defects such as uneven coating, microcracks, and pinholes at the nanometer to micrometer scale that are not visible to the naked eye, the dye of this invention can clearly expose them through local differences in color depth or fluorescence intensity. This enables a visualized and precise diagnosis of the quality of hydrophilic functional layers, successfully transforming the assessment of the microscopic quality of precise hydrophilic functional layers into a routine operation that can be completed under ordinary light (or ultraviolet light) in a fast, intuitive, low-cost, and reliable manner.

[0018] As a preferred embodiment of this technical solution, in step S1, during the staining process, the volume of the specific dye for the hydrophilic functional layer corresponding to each 1g of hydrophilic membrane is 138-173mL, and more preferably, the volume of the specific dye for the hydrophilic functional layer corresponding to each 1g of hydrophilic membrane is 150mL. More preferably, the immersion time is controlled to be 0.5-2 hours.

[0019] More preferably, the dyeing process involves immersion in a water bath at 50°C for 1 hour.

[0020] As a preferred embodiment of this technical solution, in step S2, the curing process involves drying at 30-40°C for 5-30 minutes.

[0021] More preferably, the curing process involves drying at 37°C for 10 minutes.

[0022] As a preferred embodiment of this technical solution, in step S3, during the decolorization process, the dyed and cured hydrophilic membrane is immersed in an acidic solution with a pH value of 1.0-5.8 for 10-30 minutes.

[0023] More preferably, during the decolorization treatment, the dyed and cured hydrophilic membrane is immersed in an acidic solution with a pH of 2.2-5.8 for 10 minutes. As a preferred embodiment of this technical solution, the acidic solution includes any one of dilute hydrochloric acid, citric acid, phosphate, and acetic acid, and is preferably citric acid, which is relatively safe and odorless.

[0024] As a preferred embodiment of this technical solution, the application of the specific dye for the hydrophilic functional layer of the present invention in the quality control of the hydrophilic functional layer on the hydrophilic membrane is particularly suitable for the quality control of the hydrophilic membrane at the siphon channel in blood glucose test strips. The siphon channel consists of double-sided adhesive and a hydrophilic membrane, which uses the siphon principle to draw blood and guide the blood flow to the reaction area. The realization of this automatic siphon method mainly depends on the hydrophilic function of the hydrophilic functional layer on the hydrophilic membrane. The hydrophilic function of the hydrophilic membrane directly determines the detection speed of the test strip, thus affecting the accuracy and precision of the detection value. Therefore, the integrity and uniformity of the hydrophilic functional layer of the hydrophilic membrane are crucial.

[0025] The hydrophilic functional layer-specific staining agent of the present invention has at least the following beneficial effects: 1. The core of the hydrophilic functional layer specific dye of this invention lies in the unique multiple binding mechanism between 9-(2-carboxyphenyl)-3,6-bis(diethylamino)thionyl chloride and the hydrophilic functional layer polymer. Specifically, the hydrophilic functional layer is usually rich in anionic groups such as carboxyl groups and sulfonate groups, while the specific dye used in this invention is a cationic fluorescent dye. When the two come into contact, a strong and rapid electrostatic attraction occurs first. Under this electrostatic effect, the dye molecules preferentially and firmly bind to the negatively charged hydrophilic functional layer. At the same time, a small number of dye molecules may be physically adsorbed onto the electrically neutral or hydrophobic polymer substrate layer through weak van der Waals forces or hydrophobic interactions. Based on the initial electrostatic binding, the large π-conjugated system of the oxanthracene ring at the core of the dye molecule can undergo "π-π stacking" with the aromatic rings or other conjugated structures in the hydrophilic polymer chain, which can further "lock" the dye molecules onto the polymer backbone from multiple sites. Therefore, under the synergistic effect of electrostatic attraction and "π-π stacking," the hydrophilic functional layer-specific staining agent of this invention forms a binding energy far exceeding that of a single force with respect to the hydrophilic functional layer. During the elution phase, the H in the solution... + As the concentration increases, these H + The dye competitively geocations the anionic sites such as carboxyl and sulfonic acid groups on the hydrophilic functional layer, neutralizing their charge and thus partially weakening the electrostatic attraction between the dye and the functional layer. However, due to the strong secondary anchoring effect of "π-π stacking" between the hydrophilic functional layer and the dye, this binding is sufficient to resist the impact of acidic environments, allowing most of the dye molecules to be retained. In contrast, the substrate layer and the dye only have weak physical adsorption and lack a secondary anchoring mechanism. Under acidic environments, this weak binding force is completely destroyed, causing the adsorbed dye molecules to rapidly dissociate and dissolve in the eluent. Therefore, the hydrophilic functional layer-specific dye of this invention, after staining the hydrophilic membrane, exhibits extremely high color contrast between the hydrophilic functional layer and the substrate layer, with a clean and clear background, ensuring the accuracy of observation and judgment. 2. The long-chain molecules of the hydrophilic polymeric auxiliaries can unwind in water, physically blocking 9-(2-carboxyphenyl)-3,6-bis(diethylamino)thionyl chloride dye molecules through steric hindrance, preventing their aggregation and ensuring the long-term stability and uniformity of the dyeing agent working solution. Furthermore, the aqueous solution of the hydrophilic polymeric auxiliaries can effectively wet the porous structure of the hydrophilic functional layer, guiding dye molecules into the coating interior and binding to deeper anionic sites, thus more accurately reflecting the three-dimensional integrity of the entire functional layer and achieving uniform, moderate, and consistent dyeing. Finally, during elution, the hydrophilic polymer chains themselves can weakly adsorb onto the substrate surface, competing with residual dye molecules for adsorption sites. Simultaneously, hydrophobic dye molecules eluted from the substrate layer can be encapsulated or solubilized by the polymeric auxiliaries, preventing their re-adsorption to other parts of the membrane, achieving deep background purification. Therefore, the hydrophilic polymeric auxiliaries and specific dyes in the hydrophilic functional layer specific dye of the present invention together ensure the beneficial effects of high specificity, high uniformity, high contrast and high reliability. Attached Figure Description

[0026] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0027] Figure 1 This is a flowchart of the method for staining hydrophilic membranes using the hydrophilic functional layer-specific staining agent of the present invention; Figure 2 This is one of the staining effect diagrams of different dyes on hydrophilic membranes according to the present invention; Figure 3 This is the second image showing the staining effect of different dyes on the hydrophilic membrane according to the present invention; Figure 4 The following are the effects of the eluent at different pH values ​​in this invention; Figure 5 This is a staining effect diagram of the hydrophilic membrane of the defective sample of the present invention. Detailed Implementation

[0028] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0029] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0030] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] In the following embodiments, the hydrophilic membrane 1 used is a hydrophilic membrane with a strong hydrophilic functional layer produced by AR Company, and its appearance is light milky white; the hydrophilic membrane 2 used is a hydrophilic membrane with a non-strong hydrophilic functional layer produced by 3M Company, and its appearance is completely transparent.

[0032] Example 1 The preparation of a hydrophilic functional layer-specific staining agent includes the following steps: Prepare a 1% polyethylene glycol aqueous solution; A hydrophilic functional layer-specific staining agent with a concentration of 0.1% of 9-(2-carboxyphenyl)-3,6-bis(diethylamino) tungstate chloride was prepared by adding 9-(2-carboxyphenyl)-3,6-bis(diethylamino) tungstate chloride to a 1% aqueous solution of polyethylene glycol.

[0033] like Figure 1 As shown, the method for staining hydrophilic membranes with a hydrophilic functional layer-specific staining agent includes the following steps: S1. The hydrophilic membrane with the protective layer removed is immersed in the above-mentioned hydrophilic functional layer specific staining agent and stained in a water bath at 50°C for 1 hour. The volume of the staining agent corresponding to each 1g of hydrophilic membrane is 150mL. S2. The dyed hydrophilic membrane is dried at 37°C for 15 minutes to obtain a dyed and cured hydrophilic membrane. S3. Soak the dyed and cured hydrophilic membrane in a citric acid solution with a pH of 2.2 for 10 minutes to perform decolorization treatment; S4. Observe the staining on the surface of the hydrophilic membrane. The stained area represents the hydrophilic functional layer, and the unstained area represents the absence of the hydrophilic functional layer or the substrate layer.

[0034] Compare with Example 1 This comparative example is basically the same as Example 1, except that an aqueous solution of 0.1% acid fuchsin is used instead of an aqueous solution of 0.1% 9-(2-carboxyphenyl)-3,6-bis(diethylamino) tonne chloride.

[0035] Compare with Example 2 This comparative example is basically the same as Example 1, except that: an aqueous solution of 0.1% Alkali Blue 6B is used instead of an aqueous solution of 0.1% 9-(2-carboxyphenyl)-3,6-bis(diethylamino) thionyl chloride.

[0036] Compare with Example 3 This comparative example is basically the same as Example 1, except that: 0.1% aqueous solution of amaranth is used instead of 0.1% aqueous solution of 9-(2-carboxyphenyl)-3,6-bis(diethylamino) thionyl chloride.

[0037] Compare with Example 4 This comparative example is basically the same as Example 1, except that: an aqueous solution of 0.1% tricalcium bisaluminum carmine acid complex is used instead of an aqueous solution of 0.1% 9-(2-carboxyphenyl)-3,6-bis(diethylamino) tonne chloride.

[0038] Compare with Example 5 This comparative example is basically the same as Example 1, except that: an aqueous solution of 0.1% methyl orange is used instead of an aqueous solution of 0.1% 9-(2-carboxyphenyl)-3,6-bis(diethylamino) thionyl chloride.

[0039] Compare with Example 6 This comparative example is basically the same as Example 1, except that an aqueous solution of 0.1% indigo carmine is used instead of an aqueous solution of 0.1% 9-(2-carboxyphenyl)-3,6-bis(diethylamino) tonne chloride.

[0040] Compare with Example 7 This comparative example is basically the same as Example 1, except that: an aqueous solution of 0.1% dye FD&C 40 is used instead of an aqueous solution of 0.1% 9-(2-carboxyphenyl)-3,6-bis(diethylamino) thionyl chloride.

[0041] Depend on Figure 2 It can be seen that the staining agents in Example 1 (9-(2-carboxyphenyl)-3,6-bis(diethylamino) thionyl chloride) and Control Example 1 (acid fuchsin) of the present invention can both stain the hydrophilic membrane. Among them, the staining agent of Example 1 of the present invention has the best staining effect, while the color of Control Example 1 is light and difficult to distinguish after elution. The staining agents of Control Examples 2-7 are basically unable to stain the hydrophilic membrane.

[0042] Example 2 The preparation of a hydrophilic functional layer-specific staining agent includes the following steps: Prepare a 1% polyethylene glycol aqueous solution; A hydrophilic functional layer-specific staining agent with a concentration of 0.1% of 9-(2-carboxyphenyl)-3,6-bis(diethylamino) tungstate chloride was prepared by adding 9-(2-carboxyphenyl)-3,6-bis(diethylamino) tungstate chloride to a 1% aqueous solution of polyethylene glycol.

[0043] like Figure 1 As shown, the method for staining hydrophilic membranes with a hydrophilic functional layer-specific staining agent includes the following steps: S1. Treat the hydrophilic membrane 1 and hydrophilic membrane 2 to be stained, with one end of the hydrophilic functional layer intact and the other end of the hydrophilic functional layer destroyed. Then, remove the protective layer of hydrophilic membrane 1 and hydrophilic membrane 2 respectively and immerse them in the above-mentioned staining agent. Stain them in a water bath at 50°C for 1 hour. The volume of the specific staining agent for the hydrophilic functional layer corresponding to each 1g of hydrophilic membrane is 150mL. S2. The dyed hydrophilic membrane is dried at 37°C for 15 minutes to obtain a dyed and cured hydrophilic membrane. S3. Soak the dyed and cured hydrophilic membrane in a citric acid solution with a pH of 2.2 for 10 minutes to perform decolorization treatment; S4. Observe the staining on the surface of the hydrophilic membrane. The stained area represents the hydrophilic functional layer, and the unstained area represents the absence of the hydrophilic functional layer or the substrate layer.

[0044] Compare with Example 8 This comparative example is basically the same as Example 2, except that 0.1% of the staining agent was prepared using 1% copovidone.

[0045] Compare with Example 9 This comparative example is basically the same as Example 2, except that 0.1% of the dyeing agent is prepared using 1% polyvinylpyrrolidone.

[0046] Compare with Example 10 This comparative example is basically the same as Example 2, except that 0.1% of the dyeing agent is prepared using 1% polyvinyl alcohol.

[0047] Compare with Example 11 This comparative example is basically the same as Example 2, except that 0.1% of the staining agent was prepared with purified water.

[0048] Depend on Figure 3It can be seen that dyes prepared using different hydrophilic polymer auxiliaries and pure water can basically achieve the dyeing of hydrophilic membrane 1 and hydrophilic membrane 2. Among them, the dye prepared with polyethylene glycol aqueous solution in Example 2 of the present invention has the best elution effect, the substrate layer is washed more cleanly, and the dyeing contrast between the hydrophilic functional layer and the substrate layer is stronger.

[0049] Example 3 One end of the hydrophilic membrane 1 was stained, cured and eluted using the hydrophilic functional layer-specific dye prepared in Example 1 of the present invention, while the other end was left untreated. One end of the hydrophilic membrane 2 was stained, cured and eluted using the hydrophilic functional layer-specific dye prepared in Example 1 of the present invention, while the other end was left untreated. Contact angle tests were performed on the dyed and untreated portions of hydrophilic membranes 1 and 2, respectively, and the test results are shown in Table 1.

[0050] Table 1 Contact Angle Test Results

[0051] As shown in Table 1, after immersion, curing, and elution treatment of hydrophilic membranes 1 and 2 using the hydrophilic functional layer-specific dye of the present invention, the surface contact angle of the hydrophilic membranes remained less than 20°. This further demonstrates that the hydrophilic functional layer was not damaged in any way during the immersion, curing, and elution processes. In particular, for hydrophilic membrane 2, which has weak adhesion to the substrate layer, no detachment of the hydrophilic functional layer occurred during the dyeing process.

[0052] Example 4 The hydrophilic membranes 1 and 2 to be stained were treated such that the hydrophilic functional layer at one end was intact and the hydrophilic functional layer at the other end was destroyed. The hydrophilic membrane 1 and hydrophilic membrane 2 were impregnated and cured using the hydrophilic functional layer-specific dye prepared in Example 1 of the present invention. The hydrophilic membrane was decolorized by soaking in citric acid eluents with different pH values ​​for 10 minutes, and the color difference value of the hydrophilic membrane after elution with different pH values ​​was calculated. The pH values ​​were 1.0, 2.2, 3.6, 4.6, 5.8, 6.0, 6.5 and 7.0. The color difference test results are shown in Table 2.

[0053] Table 2 Color difference test results

[0054] Depend on Figure 4 As shown in Table 2, when using an elution buffer with a pH of 1.0-5.8, the decolorization effect of the substrate layer is better, while the stained parts of the hydrophilic functional layer will not be decolorized. Among them, the elution effect is best when the pH is 2.2-5.8.

[0055] Example 5 The defective hydrophilic membranes (samples 1-4) were stained using the specific staining agent and method for hydrophilic functional layers described in Example 1, and the quality of the hydrophilic membranes was then analyzed. Images of the stained hydrophilic membranes are shown below. Figure 5 As shown in Table 3, the color difference values ​​between the hydrophilic functional layer and the substrate layer after dyeing are shown in Table 3.

[0056] Table 3 Color difference values ​​between the hydrophilic functional layer and the substrate layer after dyeing

[0057] Depend on Figure 5 As shown in Table 3, the hydrophilic functional layers of samples 1-4 exhibit varying degrees of damage. Specifically, samples 1 and 2 show defects at their centers, while samples 3 and 4 show uneven coating of their hydrophilic functional layers. This demonstrates that the water-functional layer-specific staining agent and staining method of the present invention can perform rapid, high-contrast visual analysis of the hydrophilic functional layer.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hydrophilic functional layer-specific staining agent, characterized in that, It consists of 0.01%-0.5% xanthracene fluorescent dye and 0.1%-5% hydrophilic polymeric auxiliaries, with the balance being water; The oxane fluorescent dye is 9-(2-carboxyphenyl)-3,6-bis(diethylamino) thionyl chloride.

2. The hydrophilic functional layer-specific staining agent according to claim 1, characterized in that, The hydrophilic polymeric additives include any one of polyethylene glycol, copovidone, polyvinylpyrrolidone, and polyvinyl alcohol; Preferably, the hydrophilic polymeric additive is polyethylene glycol.

3. The hydrophilic functional layer-specific staining agent according to claim 1, characterized in that, In the hydrophilic functional layer specific staining agent, the mass concentration of 9-(2-carboxyphenyl)-3,6-bis(diethylamino) in tonne chloride is 0.05%-0.3%.

4. The hydrophilic functional layer-specific staining agent according to claim 1, characterized in that, In the hydrophilic functional layer specific staining agent, the mass concentration of the hydrophilic polymeric auxiliary agent is 0.5%-2%.

5. A method for preparing the hydrophilic functional layer-specific staining agent according to any one of claims 1-4, characterized in that, Includes the following steps: A hydrophilic polymeric auxiliaries are dissolved in water to prepare a polymeric aqueous solution; Anthracene fluorescent dyes are added to an aqueous solution of a polymer and stirred until completely dissolved to obtain a hydrophilic functional layer-specific staining agent.

6. The application of the hydrophilic functional layer-specific dye according to any one of claims 1-4 in the hydrophilic functional layer on a hydrophilic membrane, characterized in that, Includes the following steps: S1. Remove the protective layer of the hydrophilic membrane and immerse it in a specific staining agent for the hydrophilic functional layer, and perform staining in a water bath at 40-60℃. S2. The dyed hydrophilic membrane is cured to obtain a dyed and cured hydrophilic membrane; S3. Immerse the dyed and cured hydrophilic membrane in an acidic solution for decolorization. S4. Observe the staining on the surface of the hydrophilic membrane. The stained area represents the hydrophilic functional layer, and the unstained area represents the absence of the hydrophilic functional layer or the substrate layer.

7. The application according to claim 6, characterized in that, In step S1, during the staining process, the volume of the specific staining agent for the hydrophilic functional layer corresponding to each 1g of hydrophilic membrane is 138-173mL. Preferably, the immersion time is controlled to be 0.5-2 hours.

8. The application according to claim 6, characterized in that, In step S2, the curing process involves drying at 30-40°C for 5-30 minutes.

9. The application according to claim 6, characterized in that, In step S3, during the decolorization process, the dyed and cured hydrophilic membrane is immersed in an acidic solution with a pH of 1.0-5.8 for 10-30 minutes.

10. The application according to claim 6, characterized in that, The acidic solution includes any one of dilute hydrochloric acid, citric acid, phosphate, and acetic acid.

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