PH response type self-repairing electrostatic spinning fiber material as well as synthesis method and application thereof

Abstract

The invention provides a pH response type self-repairing electrostatic spinning fiber material and a synthesis method and application thereof.According to the method, pH response type micro / nano containers are evenly distributed in a polymer matrix through the electrostatic spinning technology, so that the self-repairing function of a coating is achieved, and the method is particularly suitable for the field of anticorrosive coatings.

Description

Technical Field

[0001] The present invention relates to the field of functional material technology, specifically a pH-responsive self-healing electrospun fiber material and its synthesis method and application, especially a self-healing coating technology for use in the fields of anti-corrosion coatings, smart coatings, etc. Background Art

[0002] Metal corrosion is a common and significant problem in industrial production, especially for light metals such as magnesium alloys, which are highly corrosive in complex environments. While traditional anti-corrosion coatings can provide a certain physical barrier, they can easily fail after mechanical damage or prolonged use, leading to corrosion of the metal substrate. Therefore, the development of self-healing coatings to achieve automatic repair and extend the service life of metal materials has become a research hotspot.

[0003] Research on self-healing coatings primarily focuses on micro- and nano-container technology. These containers release stored repair agents upon coating damage, repairing the damaged areas through physical or chemical reactions. However, existing self-healing coatings still face challenges such as uneven container distribution, low repair efficiency, and short repair times. Therefore, addressing these issues through rational material design and optimized manufacturing processes remains a challenge in self-healing technology.

[0004] Electrospinning technology has been widely used in self-healing coatings due to its ability to produce fiber networks with high specific surface areas. By embedding micro- / nanocontainers into fiber materials, a more uniform distribution of the repair agent can be achieved, improving repair efficiency. However, current research has largely focused on conventional micro- / nanocontainers, lacking in-depth exploration of pH-responsive self-healing coatings. Controlling the self-healing process by regulating environmental factors (such as pH) is an important approach to improving coating performance. Summary of the Invention

[0005] The purpose of the present invention is to provide a pH-responsive self-healing electrospun fiber material and a synthesis method thereof, and to use electrospinning technology to evenly distribute pH-responsive micro / nanocontainers in a polymer matrix to achieve the self-healing function of the coating, which is particularly suitable for the field of anti-corrosion coatings.

[0006] To achieve the above object, the present invention provides the following technical solutions: In a first aspect, the present invention provides a pH-responsive self-healing electrospun fiber material, which includes a polymer matrix, a pH-responsive micro / nanocontainer and a corrosion inhibitor, wherein the pH-responsive micro / nanocontainer and the corrosion inhibitor are composited to form a pH-responsive micro / nanocontainer loaded with the corrosion inhibitor, and the polymer matrix material is a polymer material that can be prepared by electrospinning technology, which forms a fiber network to constitute the polymer matrix of the pH-responsive self-healing electrospun fiber material, and the pH-responsive micro / nanocontainer loaded with the corrosion inhibitor is embedded in the fibers of the fiber network.

[0007] Preferably, the polymer matrix material includes any one or more of polyacrylonitrile, polylactic acid, polyvinylidene fluoride or polycaprolactone.

[0008] Preferably, the pH-responsive micro / nano container is selected from any one or more of nanotube carrier materials, nanoparticle carrier materials, two-dimensional sheet nanomaterials, and metal-organic framework materials.

[0009] In a second aspect, the present invention provides a method for synthesizing the pH-responsive self-healing electrospinning fiber material as described above, comprising the following steps: S1, preparing a pH-responsive micro / nano container, and compounding the pH-responsive micro / nano container with a corrosion inhibitor in a solvent to form a pH-responsive micro / nano container loaded with the corrosion inhibitor; S2, dissolving the polymer matrix material in a solvent, and mixing the pH-responsive micro / nano container loaded with the corrosion inhibitor prepared in step S1 with the solution to form an electrospinning solution; S3. The electrospinning solution prepared in step S2 is loaded into a syringe of an electrospinning device, and the electrospinning solution is sprayed onto a receiver to form a fiber network after the solvent evaporates.

[0010] Preferably, the electrospinning solution comprises, by mass percentage, 10-20% polymer matrix material, 75-85% solvent, and 1-8% micro / nano containers.

[0011] Preferably, the solvent is any one or more of hexafluoroisopropanol, acetone, and N,N-dimethylformamide.

[0012] Preferably, in step S1, the pH-responsive micro / nano container and the corrosion inhibitor are compounded in a solution under ultrasonic dispersion, wherein the temperature range is 25-40° C., the ultrasonic dispersion is performed for 30-60 minutes, and then stirred at a speed of 600-3000 rpm for 1-3 hours.

[0013] Preferably, in step S2, the preparation conditions of the electrospinning solution are: a temperature range of 50-90°C, and stirring at a rotation speed of 600-3000 rpm for 4-48 hours.

[0014] Specifically, the electrospinning process in step S3 is as follows: Fix tin foil or aluminum foil on the receiver according to the appropriate size, install the syringe needle for electrospinning solution, and then turn on the power to perform electrospinning synthesis. First, set the translation distance, set the front dead point of the injection device to zero, use a syringe capacity of 5~10mL, set the voltage to 15~20KV, the injection rate to 1~2 ml / h, and the receiving distance to 5~20cm. At the same time, the spinning environment needs to be filled with inert protective gas in the preparation chamber.

[0015] In a third aspect, the present invention provides a use of the pH-responsive self-healing electrospun fiber material as described above for preparing a self-healing anti-corrosion paint or coating.

[0016] In a fourth aspect, the present invention provides a self-healing anti-corrosion coating, which comprises an organic coating and the pH-responsive self-healing electrospun fiber material as described above.

[0017] Preferably, the mass ratio of the pH-responsive self-healing electrospinning fiber material to the organic coating is 1:1 to 20.

[0018] Preferably, the organic coating is any one or more of epoxy resin coating, polyurethane coating, and alkyd resin coating.

[0019] In a fifth aspect, the present invention also provides a method for using the self-repairing anti-corrosion coating as described above, the method comprising applying the self-repairing anti-corrosion coating to the surface of a substrate, and drying it at room temperature to obtain a self-repairing anti-corrosion coating.

[0020] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a method for synthesizing a pH-responsive, self-healing electrospun fiber material and a method for preparing a fiber network coating. The synthesized electrospun fiber contains micro- / nanocontainers that are sensitive to acidic or alkaline environments. Under pH fluctuations, the micro- / nanocontainers respond to the stimulus and release corrosion inhibitors, effectively repairing damaged areas and restoring the protective function of the coating.

[0021] The pH-responsive nature of the material enables the coating to automatically repair itself based on environmental changes, avoiding the problem of increased corrosion in conventional coatings after damage, thereby extending the coating's service life.

[0022] During the repair process after damage, the coating of the present invention can effectively prevent further intrusion of corrosive media, avoid local corrosion damage to the metal substrate, and protect the structural integrity of the substrate material.

[0023] The coating material of the present invention is suitable for metal materials such as magnesium alloys and steel, and exhibits excellent corrosion resistance and self-repairing ability, especially in an environment that is highly corrosive to magnesium alloys.

[0024] The synthesis method of the coating includes mixing pH-responsive micro / nanocontainers with a polymer solution, preparing a fiber network through an electrospinning process, and then forming a coating through a curing process, which is highly efficient and controllable.

[0025] The coating material of the present invention can also further expand its application field by further optimizing the design of the micro / nano container and adjusting the properties of the polymer matrix to improve the weather resistance, aging resistance and mechanical properties of the coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a scanning electron microscope photograph of the synthetic fiber network structure of Example 1; Figure 2 is a transmission electron microscope photograph of the fiber of Example 1, showing that the micro / nano container is successfully embedded in the fiber; Figure 3 The impedance comparison of the self-repairing coating prepared in Example 1 in a 3.5% sodium chloride solution 10 hours before and after scratching; Figure 4 This is a scanning electron microscope photograph of the network structure of the synthetic fiber of Example 2; Figure 5 This is a transmission electron microscope photograph of the fiber of Example 2, showing that the micro / nano container is successfully embedded in the fiber; Figure 6 The self-repairing coating prepared in Example 2 is subjected to a comparison of coating impedance 18 hours before and after scratching in a 3.5% sodium chloride solution. DETAILED DESCRIPTION

[0027] The present invention provides a pH-responsive self-healing electrospinning fiber material and a synthesis method thereof, belonging to the field of functional material technology. The material is prepared by uniformly incorporating pH-responsive micro / nano containers into a polymer matrix and adopting an electrospinning process. The composition of the spinning solution is as follows by mass percentage: 10-20% polymer matrix, 75-85% solvent, and 2-8% micro / nano containers. During the preparation process, an ultrasonic-assisted dispersion process is adopted to ensure the uniform distribution of the micro / nano containers in the polymer solution, and the uniformity and controllability of the fibers are ensured by precisely controlling the electrospinning parameters. The synthesized fibers can realize pH-responsive self-healing functions in local areas of the coating, significantly improving the long-term stability and anti-corrosion performance of the coating. The material has broad application prospects, especially in the field of self-healing anti-corrosion coatings, showing excellent application potential.

[0028] In an exemplary embodiment, the pH-responsive self-healing electrospun fiber material of the present invention includes a polymer matrix, and pH-responsive micro / nano containers embedded in the polymer matrix structure.

[0029] According to the coating material of the present invention, the polymer matrix material can be polyacrylonitrile (PAN), polylactic acid (PLA), polyvinylidene fluoride, polycaprolactone or other polymer materials that can be prepared by electrospinning technology, ensuring that the fiber material has excellent mechanical properties and appropriate controllability.

[0030] The pH-responsive self-healing material is composed of a polymer matrix and a micro / nano container, wherein the micro / nano container can respond to changes in environmental pH and release corrosion inhibitors to repair the coating when it is damaged, thereby enhancing the long-term stability and corrosion resistance of the coating. The micro / nano container is a pH-responsive material that can repair the damaged area by releasing the stored repair agent when the coating is damaged or the environmental pH changes, thereby realizing the self-healing function of the coating. The coating of the present invention has a controllable repair process. By regulating the micro / nano container, the release of the corrosion inhibitor under specific circumstances can be accurately controlled to ensure the continuity and stability of the self-healing effect.

[0031] The micro / nanocontainers used in this invention include nanotube carrier materials (such as titanium dioxide nanotubes), two-dimensional sheet carrier materials (such as functionalized MXene materials), nanoparticle materials (such as silica nanoparticles and tin dioxide), metal-organic frameworks (MOFs), and nanocapsules (such as PPy nanocapsules). Some of these materials are inherently pH-responsive. For example, MXene materials contain abundant carboxyl and hydroxyl functional groups on their surfaces. These groups react with hydrogen ions in response to pH changes, changing their charge state and controlling the release of corrosion inhibitors. MOFs, due to their highly ordered pore structure and surface functional groups, can trigger pore structure changes and release corrosion inhibitors in response to pH changes. PPy nanocapsules, through charge transfer and swelling effects, become protonated in acidic environments, thereby controlling the release of corrosion inhibitors. While some other materials lack significant pH responsiveness, they can be rendered pH-responsive through surface modification, compounding with pH-sensitive polymers, or chemical bonding. For example, TiO2 nanotubes can be encapsulated with pH-sensitive polymers such as polyethyleneimine, causing them to swell in acidic environments, triggering the release of corrosion inhibitors. Silica and tin dioxide nanoparticles can release corrosion inhibitors under varying pH conditions by introducing pH-sensitive chemical bonds such as ester and peptide bonds, or through the protonation / deprotonation effects of the polymers. These micro- and nano-containers, through precise design and regulation, enable the self-healing function of corrosion inhibitors under varying pH conditions, ensuring the long-term stability and corrosion protection of the coating.

[0032] The synthesized electrospun material can be mixed with an organic coating in a mass ratio of 1:1-20, applied to the substrate surface, and dried at room temperature for 48 hours to obtain a self-repairing anti-corrosion coating. The organic coating can be any one of epoxy resin coating, polyurethane coating, and alkyd resin coating.

[0033] The pH responsiveness of the material enables the coating to automatically repair itself according to changes in the environment, avoiding the problem of increased corrosion of conventional coatings after being damaged, thereby extending the service life of the coating. During the repair process after being damaged, the coating of the present invention can effectively prevent further intrusion of the corrosive medium, avoid local corrosion damage to the metal matrix, and protect the structural integrity of the matrix material. The coating material of the present invention is suitable for metal materials such as magnesium alloys and steel, and exhibits excellent corrosion resistance and self-repairing ability, especially in environments with high corrosiveness to magnesium alloys. The coating material of the present invention can also further expand its application field by further optimizing the design of the micro / nano container and adjusting the properties of the polymer matrix to improve the weather resistance, aging resistance and mechanical properties of the coating.

[0034] The present invention provides a method for synthesizing a pH-responsive self-healing electrospun fiber material and a method for preparing a fiber network coating. The synthesized electrospun fiber contains micro / nanocontainers that are sensitive to acidic or alkaline environments. In a pH-changing environment, the micro / nanocontainers respond to the stimulus and release corrosion inhibitors, effectively repairing damaged areas and restoring the protective function of the coating. The controllable synthesis method of the coating includes mixing the pH-responsive micro / nanocontainers with a polymer solution, preparing a fiber network through an electrospinning process, and then forming a coating through a curing process. The method is highly efficient and controllable.

[0035] The coating material is prepared using electrospinning technology, in which the polymer fiber network forms a three-dimensional structure, providing a continuous transmission channel, which can efficiently transport the repair agent to the damaged area and significantly improve the self-repair performance of the coating.

[0036] During the preparation of the fiber network, ultrasound-assisted dispersion and stirring processes are used to ensure the uniform distribution of micro / nano containers in the polymer solution, prevent container agglomeration, and improve the uniformity and consistency of the fibers.

[0037] In the present method, the electrospinning solution comprises, by mass percentage, 10-20% polymer matrix material, 75-85% solvent, and 1-8% micro / nanocontainers. The electrospinning solution is injected into the solution channel of an electrospinning apparatus for electrospinning synthesis, thereby obtaining a pH-responsive self-healing electrospun fiber material.

[0038] The specific implementation steps are as follows: 1) Synthesis of electrospinning solution: By mass percentage, add 10-20% polymer matrix, 75-85% solvent, and 2-8% micro / nano container. The order of adding drugs is as follows: 1.1) The pH-responsive micro / nanocontainer is mixed with a solvent and ultrasonically dispersed for 30-60 minutes at a temperature range of 25-40°C, followed by stirring at a speed of 600-3000 rpm for 1-3 hours. 1.2) Then add the polymer matrix material solution and stir at a temperature range of 50-90°C and a speed of 600-3000 rpm for 4-48 hours; 2) Electrospinning synthesis: Fix the tin foil or aluminum foil of appropriate size on the receiver, install the syringe needle of the electrospinning solution, and then turn on the power to perform electrospinning synthesis. Specifically: 2.1) First, set the translation distance, set the front dead center of the injection device to zero, use a syringe volume of 5-10 mL, set the voltage to 15-20 kV, the injection rate to 1-2 ml / h, and the receiving distance to 5-20 cm; 2.2) The spinning environment needs to be filled with inert protective gas in the preparation chamber; 2.3) After spinning for 30 minutes, a shaped spun solid sample can be obtained. The synthesized electrospinning material and the organic coating are mixed in a mass ratio of 1:1 to 20, coated on the surface of the substrate, and dried at room temperature for 48 hours to obtain a self-healing anti-corrosion coating.

[0039] The solvent used in step 1) can be any one or more of hexafluoroisopropanol, acetone, and N,N-dimethylformamide.

[0040] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0041] In the description of the present invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," "the other end," and the like, which indicate positions or relationships, are used solely to facilitate description and simplify the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0042] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "installed," "provided with," "connected," etc., should be understood in a broad sense. For example, "connected" may refer to a fixed connection, a detachable connection, or an integral connection; it may refer to a mechanical connection or an electrical connection; it may refer to a direct connection or an indirect connection through an intermediate medium; it may refer to internal communication between two components. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0043] The following is a detailed description of a pH-responsive self-repairing electrospinning fiber material, a synthesis method, and applications of the present invention in conjunction with specific embodiments and accompanying drawings.

[0044] The present invention provides a pH-responsive self-repairing fiber material, which comprises the synthesis of micro / nano containers and the combination of the micro / nano containers with a polymer matrix through electrospinning technology to form a fiber material with self-repairing function.

[0045] Example 1

[0046] The present invention provides a pH-responsive TiO2 nanotube self-repairing electrospinning fiber material, and the specific steps of its synthesis method are as follows: (1) Synthesis of TiO2 nanotubes: TiO2 nanotubes were synthesized by hydrothermal method. Under continuous stirring, 1.2 g of TiO2 was added to 20 mL of 10 mol / L NaOH solution and transferred to a 75 mL reactor (lined with polytetrafluoroethylene) for hydrothermal reaction at 130 °C for 15 hours. After the reaction, it was cooled to room temperature. The reaction product was separated into solid and liquid by a high-speed centrifuge (speed 9000 rpm), and the solid was washed with ultrapure water. The washed solid was added to 2 L of 0.1 mol / L HCl solution to neutralize the residual alkali on the solid surface. It was then washed with ultrapure water several times until the pH value of the supernatant was 7.0. Finally, the TiO2 nanotubes were dried under vacuum at 60 °C for 4 hours to obtain the desired TiO2 nanotubes.

[0047] (2) Encapsulation of corrosion inhibitor 8HQ: Encapsulation of 8HQ corrosion inhibitor was achieved by vacuum-assisted technology. First, 1 g of synthesized TiO2 nanotubes and 2 g of 8HQ corrosion inhibitor were added to 60 ml of anhydrous ethanol solution and mixed under stirring. The suspension was transferred to a round-bottom flask, evacuated by a vacuum pump and stirred for 30 minutes to ensure that the trapped air inside the TiO2 nanotubes was completely released, thereby improving the encapsulation efficiency of the 8HQ corrosion inhibitor. To further optimize the encapsulation amount of 8HQ corrosion inhibitor, three vacuum cycles were performed using the same steps. Finally, TiO2-8HQ nanotubes were obtained by washing and drying.

[0048] (3) Fiber network construction: PLA was dissolved in a DMF / AC mixed solvent (volume ratio = 7:3) to prepare an electrospinning solution (10% w / v, polymer / solvent) at 45 °C. Then, different concentrations of TiO2-8HQ nanotubes (1, 2, 3 wt.%) were dispersed into the above solution and stirred for 30 minutes to achieve good dispersion. Finally, the suspension was transferred to a medical-grade syringe equipped with a metal needle. During the electrospinning process, a voltage of 18 kV was applied, the flow rate of the electrospinning solution was 1 mL / h, and the distance between the nozzle and the receiver was 15 cm. The entire electrospinning process was carried out in a controlled environment at a temperature of 25±2 °C and a relative humidity of 40±5%. During the electrospinning process, the force generated by the electric field exceeded the surface tension of the droplet, pushing the suspension to move toward the collector, and the solvent evaporated to form a fiber network. Figure 1 and 2 .

[0049] (4) Coating preparation: The synthesized fiber network sample was mixed with epoxy resin coating in a mass ratio of 1:8, coated on the surface of magnesium alloy, and dried at room temperature for 48 hours to obtain a self-repairing coating. The prepared self-repairing coating was scratched in 3.5% sodium chloride solution, and the coating impedance was compared 10 hours before and after scratching. Figure 3 It can be seen that the coating prepared in this embodiment has good corrosion resistance.

[0050] Example 2

[0051] A pH-responsive f-MXene-Ce 3+ The specific steps of the synthesis method of the sheet self-repairing electrospun fiber material are as follows: (1) Synthesis of f-MXene composite materials: Ti3C2 MXene was synthesized using a hydrofluoric acid (HF) selective etching process. First, 20 mL of 48% HF was added to a 100 mL plastic reaction vessel and stirred in a water bath (35°C). Subsequently, 2 g of Ti3AlC2 powder was slowly added to the above solution under ice bath conditions. After the etching reaction was continued at 25°C for 24 hours, a black product was obtained after washing, centrifugation, and vacuum drying at 80°C for 24 hours. Next, the MXene was modified with L-Asp. 0.5 g of MXene black powder and 0.3 g of L-Asp were dissolved in 50 mL of deionized water, and 0.01 g of 1-(3-dimethylaminopropyl)-3-ethylaminomethane (EDC) and 0.01 g of 4-dimethylaminopyridine (DMAP) were added as catalysts. After stirring and reacting at 100°C for 3 hours, the functionalized f-MXene product was collected by centrifugation, washed thoroughly with deionized water to remove unreacted reagents, and freeze-dried for storage.

[0052] (2) f-MXene-Ce 3+ Composite material synthesis: 0.1 g of f-MXene was dispersed in 50 mL of a 15 mM Ce(NO3)3 solution and allowed to stand at room temperature for 4 hours. After sonication, the suspension was adjusted to pH 8 by dropwise addition of 0.1 M NaOH. After centrifugation, the suspension was washed with a deionized water-ethanol mixture (5:1 volume ratio) and dried under vacuum at 60°C for 24 hours. The resulting product was labeled f-MXene-Ce 3+ .

[0053] (3) Fiber network construction: The fiber network was prepared using electrospinning technology in an environment of 25±2°C and 40±5% humidity. First, PAN was dissolved in a 60°C N,N-dimethylformamide (DMF) solution to prepare a 10% w / v spinning solution. Subsequently, 1wt.% of the synthesized MXene was added to the solution and stirred continuously. The mixed solution was transferred to a medical syringe equipped with a metal needle. The electrospinning parameters were set to a voltage of 18 kV, a distance of 15 cm between the needle and the receiver, and a flow rate of 1.5 mL / h. Under the action of the electric field, the surface tension of the droplets was overcome, the suspension was sprayed onto the receiver, and the solvent evaporated to form a PAN fiber network. Figure 4 and 5 .

[0054] (4) Coating preparation: The synthesized fiber network sample was mixed with epoxy resin coating in a mass ratio of 1:12, coated on the surface of magnesium alloy, and dried at room temperature for 48 hours to obtain a self-repairing coating. The prepared self-repairing coating was scratched in 3.5% sodium chloride solution, and the coating impedance was compared 18 hours before and after scratching. Figure 6 It can be seen that the coating prepared in this embodiment has good corrosion resistance.

[0055] Example 3

[0056] The present invention provides a pH-responsive 8HQ-ZM sheet self-repairing electrospinning fiber material, and the specific steps of its synthesis are as follows: (1) Preparation of ZIF-8 modified Ti3C2 MXene nanosheets (ZM): First, 0.175 g of zinc acetate dihydrate (Zn(C2O2H3)2·2H2O) was dispersed in 25 ml of MXene dispersion to form solution A. 0.527 g of 2-methylimidazole was dispersed in 25 ml of methanol to form solution B. Solution B was slowly added to solution A under stirring, and the mixture was stirred for 12 hours. After the reaction, the mixture was repeatedly washed with deionized water and concentrated, and then freeze-dried to obtain ZM nanosheets.

[0057] (2) Preparation of 8HQ-ZM sheets: 0.5 g of the prepared ZM nanosheets were dispersed in a saturated 8-hydroxyquinoline (8HQ) methanol solution and stirred continuously in a sealed container for 3 hours to increase the loading rate. The container was then evacuated. The resulting mixture was centrifuged, washed twice with methanol, and dried in a vacuum oven at 60°C to obtain black-green 8HQ-ZM nanosheets.

[0058] (3) Fiber network construction: The fiber network was prepared using electrospinning technology in an environment of 25±2℃ and 40±5% humidity. First, PAN was dissolved in a 60℃ N,N-dimethylformamide (DMF) solution to prepare a 10% w / v spinning solution. Subsequently, 1wt.% of the synthesized 8HQ-ZM nanosheets was added to the solution and stirred continuously. The mixed solution was transferred to a medical syringe equipped with a metal needle. The electrospinning parameters were set to a voltage of 18 kV, a distance between the needle and the receiver of 15 cm, and a flow rate of 1.5 mL / h. Under the action of the electric field, the surface tension of the droplet was overcome, the suspension was sprayed onto the receiver, and the solvent evaporated to form a PAN fiber network.

[0059] (4) Coating Preparation: The synthesized fiber network sample was mixed with a polyurethane coating in a mass ratio of 1:20, applied to a carbon steel surface, and dried at room temperature for 48 hours to obtain a self-healing coating. The prepared self-healing coating was scratched in a 3.5% sodium chloride solution, and the coating impedance was compared 24 hours after scratching. The coating prepared in this example exhibited good corrosion resistance.

[0060] Example 4

[0061] The present invention provides a pH-responsive tin dioxide nanocontainer self-repairing electrospinning fiber material, and the specific steps of its synthesis method are as follows: (1) Preparation of SnO2 nanocontainers: SnO2 nanoparticles were first prepared by a hydrothermal method. 1.28 g of Na2SnO3·3H2O and 1.92 g of CO(NH2)2 were dissolved in 100 ml of a water-ethanol mixture (EtOH / H2O = 0.6, V / V). The mixture was transferred to a reactor and reacted at 180°C for 24 h. After separation and washing, it was dried at 60°C and calcined at 500°C for 1 h to obtain SnO2 nanoparticles.

[0062] (2) Synthesis of SnO2 / PPy / MoO4 / PDA: A PPy layer was deposited on the surface of SnO2 nanoparticles by in situ polymerization. 0.2 g of SnO2 nanoparticles and 8 mg of sodium dodecyl sulfate (SDS) were dissolved in 80 ml of ultrapure water. After ultrasonic stirring for 3 h, 51.6 μl of Py monomer was added. 22.4 ml of 0.1 mol·L-1 (NH4)2S2O8 solution was added dropwise, and the mixture was stirred at room temperature for 6 h. After separation, the mixture was washed with ethanol and ultrapure water and dried in a vacuum at 80 °C. It was labeled as SnO2 / PPy. A Na2MoO4 layer was deposited by ultrasonication. 100 mg of SnO2 / PPy was dispersed in an ethanol solution, 10 mg·ml-1 Na2MoO4 was added, and after ultrasonication and stirring for 1 h, the mixture was separated, washed, and dried. It was labeled as SnO2 / PPy / MoO4. Finally, 60 mg of SnO2 / PPy / MoO4 was dispersed in 60 ml of Tris-HCl buffer solution (10 mmol·L-1, pH = 8.5), and 60 mg of PDA was quickly added. The mixed solution was stirred in the dark for 12 h. After separation, it was washed with ultrapure water and ethanol and dried for later use. It was labeled SnO2 / PPy / MoO4 / PDA.

[0063] (3) Fiber network construction: 1.2 g of PCL particles were added to 10 mL of hexafluoroisopropanol and magnetically stirred at room temperature for 3 h until the PCL was completely dissolved to obtain pure PCL spinning solution. PCL / SnO2 / PPy / MoO4 / PDA spinning solution was prepared by adding 5 wt%-10 wt% of cerium-substituted hydroxyapatite powder to the PCL / Col spinning solution and continuing to stir for 3 h. The above spinning solutions were transferred to 10 mL syringes respectively. The syringes were connected to the electrospinning needles with silicone hoses and then fixed on the microfluidic pump. The specific spinning voltage was 16 kV, the needle model was 18 G, the receiving distance was 10 cm, and the spinning solution flow rate was set to 2.0 mL / h.

[0064] (4) Coating Preparation: The synthesized electrospun sample was mixed with an alkyd resin coating in a mass ratio of 1:20, coated on a carbon steel surface, and dried at room temperature for 48 hours to obtain a self-healing coating. The prepared self-healing coating was scratched in a 3.5% sodium chloride solution, and the coating impedance was compared 2 days after scratching. It was found that the coating prepared in this example had good corrosion resistance.

[0065] Example 5

[0066] The present invention provides a pH-responsive PPy nanocapsule self-repairing electrospinning fiber material, and the specific steps of its synthesis are as follows: (1) Synthesis of PPy nanocapsules: 7 mL of tetraethoxysilane (TEOS, silicon source) was added to a mixed solution consisting of 8 mL of ammonia (NH3·H2O), 146 mL of ethanol, and 3 mL of ultrapure water. The solution was vigorously stirred at 25°C for 6 hours until uniform silica nanoparticles were formed. Subsequently, the silica nanoparticles were separated and dried to serve as a stable template for the subsequent deposition of the PPy shell. Next, 0.2 g of the silica template was dispersed in 20 mL of ethanol and ultrasonically dispersed. Then, 0.5 g of polyvinylpyrrolidone (PVP) was added to it, and the mixture was ultrasonically treated for another 1 hour and stirred continuously at room temperature for 24 hours to ensure that PVP was fully adsorbed on the surface of the nanoparticles. Due to the amphiphilic properties given by its polar and non-polar structures, PVP can act as a surfactant and bridging agent, providing abundant active sites for the subsequent deposition of the PPy shell.

[0067] After multiple washes with ultrapure water and ethanol, the precipitate was re-dispersed in 20 mL of ultrapure water by ultrasonication. To this dispersion, 0.9 g of the oxidant FeCl₃·6H₂O was added with stirring, followed by 0.1 mL of pyrrole (as a shell monomer). The reaction mixture was polymerized for 12 hours under continuous stirring to produce SiO₂@PPy nanoparticles. The resulting product was washed and dried overnight under vacuum at 60°C. To obtain hollow PPy nanocapsules, the SiO₂@PPy nanoparticles were immersed in a 10% (mass fraction) hydrofluoric acid (HF) solution for 24 hours to dissolve the silica core. The resulting hollow PPy nanocapsules were then washed with ultrapure water and ethanol.

[0068] The zinc salt corrosion inhibitor was encapsulated using a vacuum method. 1 g of zinc chloride (ZnCl2) was mixed with 2 g of hollow PPy nanocapsules and 80 mL of ethanol. The mixture was stirred continuously and then sonicated for 1 hour. The mixed solution was then placed in a vacuum jar and vacuumed for 24 hours. The jar was then sealed and allowed to stand for 2 hours to ensure that the ZnCl2 inhibitor was completely encapsulated within the hollow channels of the PPy nanocapsules.

[0069] (2) Fiber network construction: Weigh 2.0 g of PVDF powder and add it to 20 mL of mixed solvent (N,N-dimethylformamide (DMF): acetone = 6:4, volume ratio). Heat and stir in a 60°C water bath under magnetic stirring for 4 hours until it is completely dissolved to form a uniform and transparent polymer solution. The PVDF / PPy-Zn spinning solution is prepared by adding 5 wt%-10 wt% PPy-Zn powder to the PVDF spinning solution and continuing to stir for 3 hours. The above spinning solutions are transferred to 10 mL syringes respectively. The syringes are connected to the electrospinning needles with silicone hoses and then fixed on the microfluidic pump. The specific spinning voltage is 20 kV, the needle model is 18 G, the receiving distance is 10 cm, and the spinning solution flow rate is set to 1.5 mL / h.

[0070] (4) Coating Preparation: The synthesized electrospun sample was mixed with epoxy resin coating in a mass ratio of 1:20, coated on a carbon steel surface, and dried at room temperature for 48 hours to obtain a self-healing coating. The prepared self-healing coating was scratched in a 3.5% sodium chloride solution, and the coating impedance was compared 2 days after scratching. The coating prepared in this example has good corrosion resistance.

[0071] Anything not described in detail in the present invention is well known to those skilled in the art.

[0072] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified and replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A pH-responsive self-repairing electrospun fiber material, characterized in that: The material includes a polymer matrix, a pH-responsive micro / nanocontainer and a corrosion inhibitor, wherein the pH-responsive micro / nanocontainer and the corrosion inhibitor are composited to form a pH-responsive micro / nanocontainer loaded with the corrosion inhibitor. The polymer matrix material is a polymer material that can be prepared by electrospinning technology. The material forms a fiber network to constitute the polymer matrix of the pH-responsive self-healing electrospinning fiber material, and the pH-responsive micro / nanocontainer loaded with the corrosion inhibitor is embedded in the fibers of the fiber network.

2. The pH-responsive self-healing electrospun fiber material according to claim 1, wherein: The polymer matrix material includes any one or more of polyacrylonitrile, polylactic acid, polyvinylidene fluoride or polycaprolactone.

3. The pH-responsive self-healing electrospun fiber material according to claim 1, wherein The pH-responsive micro / nano container is selected from any one or more of nanotube carrier materials, nanoparticle carrier materials, two-dimensional sheet nanomaterials, and metal-organic framework materials.

4. The method for synthesizing a pH-responsive self-repairing electrospinning fiber material according to any one of claims 1 to 3, wherein: The method comprises the following steps: S1, preparing a pH-responsive micro / nano container, and compounding the pH-responsive micro / nano container with a corrosion inhibitor in a solvent to form a pH-responsive micro / nano container loaded with the corrosion inhibitor; S2. Dissolving a polymer matrix material in a solvent, and mixing the pH-responsive micro / nano container loaded with a corrosion inhibitor prepared in step S1 with the solution to form an electrospinning solution, wherein the electrospinning solution comprises, by mass percentage, 10-20% polymer matrix material, 75-85% solvent, and 1-8% micro / nano container; S3. The electrospinning solution prepared in step S2 is loaded into a syringe of an electrospinning device, and the electrospinning solution is sprayed onto a receiver to form a fiber network after the solvent evaporates.

5. The method according to claim 4, wherein The solvent is any one or more of hexafluoroisopropanol, acetone, and N,N-dimethylformamide.

6. The method according to claim 4, wherein In step S1, the pH-responsive micro / nanocontainer and the corrosion inhibitor are compounded in a solution under ultrasonic dispersion, wherein the temperature range is 25-40°C, the ultrasonic dispersion is carried out for 30-60 minutes, and then the mixture is stirred at a speed of 600-3000 rpm for 1-3 hours. In step S2, the preparation conditions of the electrospinning solution are: the temperature range is 50-90°C, and the stirring speed is 600-3000 rpm for 4-48 hours. The electrospinning process in step S3 is as follows: Fix tin foil or aluminum foil on the receiver according to the appropriate size, install the syringe needle for electrospinning solution, and then turn on the power to perform electrospinning synthesis. First, set the translation distance, set the front dead point of the injection device to zero, use a syringe capacity of 5~10mL, set the voltage to 15~20KV, and the receiving distance to 5~20cm. At the same time, the spinning environment needs to be filled with inert protective gas in the preparation chamber.

7. Use of the pH-responsive self-healing electrospun fiber material according to any one of claims 1 to 3 or the pH-responsive self-healing electrospun fiber material prepared by the method according to any one of claims 4 to 6 for preparing a self-healing anti-corrosion paint or coating.

8. A self-repairing anti-corrosion coating, characterized in that: The coating comprises an organic coating and a pH-responsive self-healing electrospun fiber material according to any one of claims 1 to 3 or a pH-responsive self-healing electrospun fiber material prepared by the method according to any one of claims 4 to 6.

9. The self-repairing anti-corrosion coating according to claim 8, characterized in that: The organic coating is any one or more of epoxy resin coating, polyurethane coating, and alkyd resin coating, wherein the mass ratio of the pH-responsive self-healing electrospinning fiber material to the organic coating is 1:1-20.

10. The method for using the self-repairing anti-corrosion coating according to any one of claims 8 to 9, characterized in that: The method comprises applying the self-repairing anti-corrosion coating to the surface of a substrate, and drying the coating at room temperature to obtain a self-repairing anti-corrosion coating.

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