Shape memory superhydrophobic anticorrosion coatings for marine metals, their preparation methods and applications

Abstract

This invention belongs to the field of marine engineering metal corrosion protection technology, specifically relating to a shape memory superhydrophobic anti-corrosion coating for marine engineering metals, its preparation method, and its application. The preparation method of the shape memory superhydrophobic anti-corrosion coating for marine engineering metals of this invention includes the following steps: (1) preparation of a bisphenol A resin coating; (2) preparation of a nanofiber composite coating; and (3) preparation of the shape memory superhydrophobic anti-corrosion coating. The preparation method of the shape memory superhydrophobic anti-corrosion coating for marine engineering metals of this invention is simple and low-cost. The prepared shape memory superhydrophobic anti-corrosion coating for marine engineering metals also possesses multiple excellent properties such as high impedance, wear resistance, peel resistance, and self-healing properties, exhibiting outstanding durability and showing great application potential in practical applications such as marine corrosion protection.

Description

Technical Field

[0001] This invention belongs to the field of marine engineering metal corrosion protection technology, specifically relating to a shape memory superhydrophobic anti-corrosion coating for marine engineering metals, its preparation method and application. Background Technology

[0002] Metal corrosion has always been a significant concern, and with the increasing demands for modern metal corrosion protection, numerous new anti-corrosion technologies have emerged. Organic coatings, as the most widely used and effective protective technology for metal materials, are extensively applied in various fields such as marine, chemical, transportation, and shipbuilding. With continuous improvements in coating technology, new anti-corrosion coatings have been developed. However, organic coatings inevitably develop defects such as micropores and cracks due to solvent evaporation during the curing process. Small-molecule corrosive media (such as water and chloride ions) can reach the metal substrate through these cracks or defects, initiating corrosion. Therefore, it is necessary to increase the coating's repellency to water-based media and reduce the contact area and contact time between the coating and corrosive media to improve its corrosion resistance. Simultaneously, endowing the coating with self-healing properties is also a crucial means of extending its service life.

[0003] In addition, traditional superhydrophobic coatings have poor mechanical properties and their surface micro-nano structures are easily damaged, leading to failure of hydrophobic properties and thus failing to provide long-term protection.

[0004] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0005] The purpose of this invention is to provide a shape memory superhydrophobic anti-corrosion coating for marine engineering metals, its preparation method and application, so as to help solve or improve at least one of the problems of easy cracking, easy failure of hydrophobic properties and short service life of anti-corrosion coatings on the surface of marine engineering metals, so as to help improve the protective effect of anti-corrosion coatings applied to marine engineering metals.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a shape memory superhydrophobic anticorrosive coating for marine engineering metals, comprising the following steps: (1) Preparation of bisphenol A resin coating: bisphenol A diglycidyl ether, neopentyl glycol diglycidyl ether and n-n-decylamine are mixed evenly to obtain a resin coating solution, and the resin coating solution is coated on a metal substrate. After the resin coating solution reaches a surface dry state, a metal substrate coated with bisphenol A resin coating is obtained; the mass ratio of bisphenol A diglycidyl ether, neopentyl glycol diglycidyl ether and n-n-decylamine is (1-4):(1-3):1; (2) Preparation of nanofiber composite coating: electrospinning is performed on the surface of the metal substrate coated with bisphenol A resin coating to obtain the nanofiber composite coating; The components of the electrospinning solution include a first solvent and polycaprolactone; (3) Preparation of shape memory superhydrophobic anti-corrosion coating: the superhydrophobic coating solution is sprayed onto the surface of the nanofiber composite coating to obtain the shape memory superhydrophobic anti-corrosion coating; the components of the superhydrophobic coating solution include modified diatomaceous earth, oily epoxy resin, curing agent and second solvent; the modified diatomaceous earth is prepared by a method including the following steps: natural diatomaceous earth is dispersed in a third solvent, stirred evenly and then octadecyltrimethoxysilane is added, the temperature is first raised to a first temperature and stirred for a first time, and then stirred for a second time at room temperature, filtered, washed and dried to obtain the modified diatomaceous earth; the mass ratio of the natural diatomaceous earth to the octadecyltrimethoxysilane is 1:1-10:1.

[0007] Preferably, in step (3), the mass ratio of the oily epoxy resin to the modified diatomaceous earth is 1:2-1:10, the mass ratio of the oily epoxy resin to the curing agent is 2:1-1:1, and the mass ratio of the oily epoxy resin to the second solvent is 1:8-1:16; the second solvent is anhydrous ethanol.

[0008] Preferably, in the preparation process of the modified diatomaceous earth, the mass-to-volume ratio of the natural diatomaceous earth to the third solvent is 1:(11-12), the mass of the natural diatomaceous earth is in g, and the volume of the third solvent is in mL; the first temperature is 35-60℃, the first time is 8-16h, the second time is 6-12h, and the third solvent is ethanol.

[0009] Preferably, the spinning solution is prepared by a method comprising the following steps: A. mixing and stirring N,N-dimethylformamide and dichloromethane at a temperature of 18-25°C and a humidity of 20%-30% to obtain a first solvent; B. adding polycaprolactone to the first solvent; C. heating to 35-60°C and continuing to stir for 12-18 hours to obtain the spinning solution.

[0010] Preferably, in the first solvent, the mass ratio of N,N-dimethylformamide to dichloromethane is 1:1 to 1:6; and the mass ratio of polycaprolactone to the first solvent is (2-6):25.

[0011] Preferably, in step (2), the preparation of the nanofiber composite coating includes the following steps: fixing a syringe containing spinning solution onto an electrostatic coaxial spinning machine, connecting the coaxial needle to the positive and negative power supply, covering the collector with an aluminum foil, fixing the metal substrate coated with bisphenol A resin on the aluminum foil, and performing electrostatic spinning; the voltage of the electrostatic spinning is 7-12kV, the pushing speed of the injection pump is 0.4-0.8mm / min, and the spinning time is 20-40min; the electrostatic spinning is carried out under the condition of 20%-30% humidity.

[0012] Preferably, in step (3), the superhydrophobic coating solution is sprayed onto the surface of the nanofiber composite coating by air pressure spraying. The air pressure during air pressure spraying is 0.5-1.2 atm, the distance between the spray gun and the coating surface is 6-10 cm, the spraying time is 15-25 s, and the number of spraying times is 1-3.

[0013] Preferably, the metal matrix is ​​made of at least one of carbon steel, magnesium alloy, aluminum alloy, copper, and titanium alloy.

[0014] The present invention also provides a shape memory superhydrophobic anti-corrosion coating for marine metals, which adopts the following technical solution: a shape memory superhydrophobic anti-corrosion coating for marine metals, characterized in that the shape memory superhydrophobic anti-corrosion coating for marine metals is prepared by the method described above.

[0015] The present invention also provides a marine engineering metal device, which adopts the following technical solution: a marine engineering metal device, wherein the surface of the marine engineering metal device is provided with a shape memory superhydrophobic anti-corrosion coating as described above.

[0016] Beneficial effects:

[0017] In the preparation method of the shape memory superhydrophobic anti-corrosion coating for marine engineering metals of the present invention, a nanofiber composite coating is obtained by electrospinning on the surface of a metal substrate coated with a resin coating. The polycaprolactone nanofibers in the nanofiber composite coating are combined with bisphenol A epoxy resin, which enables the nanofiber composite coating to have self-healing properties. Then, a coating solution containing modified diatomaceous earth and oil-based epoxy resin is sprayed onto the surface of the nanofiber composite coating, and after curing, the shape memory superhydrophobic anti-corrosion coating for marine engineering metals is obtained. The shape memory superhydrophobic anti-corrosion coating for marine engineering metals prepared by the method of the present invention helps to solve or improve the defects of existing superhydrophobic coatings such as poor mechanical properties, few repair times, and low efficiency of self-healing coatings. The preparation method of the shape memory superhydrophobic anti-corrosion coating for marine engineering metals of the present invention is simple and low in cost. The prepared shape memory superhydrophobic anti-corrosion coating for marine engineering metals also has multiple excellent properties such as high impedance, wear resistance, peel resistance, and self-healing, with outstanding durability, and has great application prospects in practical applications such as marine corrosion protection.

[0018] The nanofiber composite coating (composed of a resin coating and a nanofiber membrane obtained by electrospinning through electrospinning) in the shape memory superhydrophobic anticorrosive coating for marine metals of the present invention can not only improve the overall flexibility of the coating, but also fill the micropore defects in the coating, and at the same time give the coating a self-healing function, which can prevent and prolong the durability of the superhydrophobic coating and delay the occurrence of corrosion.

[0019] The shape memory superhydrophobic anticorrosion coating for marine metals of the present invention exhibits a high contact angle, a low sliding angle, and durable superhydrophobic properties. The nanofiber composite coating has a shape memory effect, and when the coating is damaged, it can be restored to its original surface morphology simply by heating it (e.g., heating at 50°C for 2 hours). This makes the shape memory superhydrophobic anticorrosion coating for marine metals of the present invention significantly reduce the contact area and contact time between the coating and water molecules during use, which is beneficial to preventing corrosive media from penetrating the coating.

[0020] The shape memory superhydrophobic anti-corrosion coating for marine metals of the present invention has a wide range of applications. After curing, it has good adhesion, water resistance, and salt water penetration resistance, and also has multiple self-healing properties. The process is simple, and it has excellent anti-corrosion effect and long-lasting protection. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein:

[0022] Figure 1The images shown are scanning electron microscope (SEM) images of the coatings provided in Embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention; wherein, (a) is a scanning electron microscope (SEM) image of the coating of Comparative Example 1, (b) is a scanning electron microscope (SEM) image of the coating of Comparative Example 2, and (c) is a scanning electron microscope (SEM) image of the coating of Embodiment 1.

[0023] Figure 2 These are laser confocal images of the coatings provided in Embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention; wherein, (a) is a laser confocal image of the coating of Comparative Example 1, (b) is a laser confocal image of the coating of Comparative Example 2, and (c) is a laser confocal image of the coating of Embodiment 1.

[0024] Figure 3 The images show the water contact angles of the coatings provided in Embodiment 1 and Comparative Example 2 at different times; where (a) is the water contact angle of the coating in Embodiment 1 and (b) is the water contact angle of the coating in Comparative Example 2.

[0025] Figure 4 The figures show the pull-out test results of the coatings provided in Embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention.

[0026] Figure 5 The figures are Bode plots and Nyquist plots of the coating after immersion for 45 days, provided in Embodiment 1 and Comparative Example 1 of the present invention; wherein, (a) is the Bode plot, (b1) is the Nyquist plot, and (b2) is a partial enlarged view of (b1).

[0027] Figure 6 The microstructure images are the wear resistance test results of the coating provided in Embodiment 1 of the present invention; wherein, (a1) is the microstructure image after 0 wear cycles, (a2) is the microstructure image after 60 wear cycles, (a3) ​​is the microstructure image after 120 wear cycles, and (a4) is the microstructure image after 160 wear cycles.

[0028] Figure 7 The images show the self-healing results of the coating in Example 1 of the present invention. (a) is a laser confocal image after damage in Example 1, and (b) is a laser confocal image after heat healing in Example 1.

[0029] Figure 8 The image shows the EIS test results of the coating in Embodiment 1 of the present invention after it was damaged and then self-healed by heating; where (a) is the modulus Bode plot, (b1) is the Nyquist plot, and (b2) is a magnified view of (b1). Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0031] The present invention will now be described in detail with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.

[0032] This invention addresses the problems of current anti-corrosion coatings for marine engineering metal surfaces, such as susceptibility to cracking, easy failure of hydrophobic properties, and short service life. The inventors creatively conceived of introducing self-healing capabilities into superhydrophobic coatings, a novel approach that would help improve the coating's repellency to aqueous media while simultaneously providing self-healing properties. These two functions work synergistically to offer better protection for the metal. Based on this, this invention provides a method for preparing a shape-memory superhydrophobic anti-corrosion coating for marine engineering metals, thereby helping to solve at least one of the aforementioned problems.

[0033] The method for preparing a shape memory superhydrophobic anticorrosive coating for marine metals according to an embodiment of the present invention includes the following steps:

[0034] (1) Preparation of bisphenol A resin coating:

[0035] Bisphenol A diglycidyl ether, neopentyl glycol diglycidyl ether, and n-n-decylamine are mixed evenly to obtain a bisphenol A resin coating solution. The resin coating solution is coated onto a metal substrate. After the resin coating solution reaches a surface dry state, a metal substrate coated with bisphenol A resin coating is obtained. The mass ratio of bisphenol A diglycidyl ether, neopentyl glycol diglycidyl ether, and n-n-decylamine is (1-4):(1-3):1 (e.g., 1:1:1, 4:1:1, 3:1:1, 2:1:1, 1:3:1, 1:2:1, or 2:2:1, etc.).

[0036] (2) Preparation of nanofiber composite coating:

[0037] Electrospinning is performed on the surface of a metal substrate coated with a resin coating to obtain a nanofiber composite coating; the components of the electrospinning solution include a first solvent and polycaprolactone.

[0038] (3) Preparation of shape memory superhydrophobic anticorrosive coating:

[0039] A superhydrophobic coating solution was sprayed onto the surface of a nanofiber composite coating to obtain a shape memory superhydrophobic anti-corrosion coating. The superhydrophobic coating solution consisted of modified diatomaceous earth, oily epoxy resin, curing agent, and a second solvent. The modified diatomaceous earth was prepared by a method including the following steps: natural diatomaceous earth was dispersed in a third solvent, stirred evenly, and then octadecyltrimethoxysilane was added. The mixture was first heated to a first temperature and stirred for a first time, and then stirred for a second time at room temperature. After filtration, washing, and drying, the modified diatomaceous earth was obtained. The mass ratio of natural diatomaceous earth to octadecyltrimethoxysilane was 1:1-10:1.

[0040] In this invention, the bisphenol A resin coating obtained in step (1) has certain self-healing properties; in step (2), by selecting polycaprolactone and using N,N-dimethylformamide and dichloromethane as solvents for the spinning solution, the nanofiber membrane obtained by electrospinning can have self-healing properties; the nanofiber composite coating obtained by the coordination of the bisphenol A resin coating and the nanofiber membrane obtained by electrospinning in this invention not only has self-healing properties, but also can better bond with the metal substrate, and also helps to better achieve the adhesion of hydrophobic particles in the superhydrophobic coating solution, thereby better improving the lifespan of the shape memory superhydrophobic anti-corrosion coating for marine metals prepared in this invention. In addition, the mass ratio of bisphenol A diglycidyl ether, neopentyl glycol diglycidyl ether and n-n-decylamine in the bisphenol A resin coating solution will affect the self-healing temperature of the bisphenol A resin coating. The properties of the modified diatomaceous earth used in the superhydrophobic coating solution are related to the ratio of natural diatomaceous earth to octadecyltrimethoxysilane, which in turn significantly affects the water contact angle (when the water contact angle is greater than 150°, the coating is superhydrophobic) of the shape memory superhydrophobic anticorrosive coating for marine metals. In this invention, the oily epoxy resin can improve the mechanical properties of the coating (e.g., adhesion strength).

[0041] The nanofiber composite coating of this invention is composed of a bisphenol A resin coating and a nanofiber membrane obtained by electrospinning a spinning solution containing polycaprolactone. This not only improves the overall flexibility of the coating and helps fill microporous defects, but also gives the nanofiber composite coating a self-healing effect (helping to extend the durability of the superhydrophobic coating and delay the corrosion process). Then, a superhydrophobic coating solution containing modified diatomaceous earth and oily epoxy resin is sprayed onto the surface of the nanofiber composite coating to obtain the shape memory superhydrophobic anti-corrosion coating for marine engineering metals of this invention (after spraying the superhydrophobic coating solution, the coating surface of this invention exhibits a high contact angle, a low sliding angle, and durable superhydrophobic properties). The shape memory superhydrophobic anti-corrosion coating for marine engineering metals prepared by the method of this invention not only helps to solve or improve the defects of superhydrophobic coatings such as poor mechanical properties, inability to achieve self-repair, or low self-repair frequency and efficiency, but also has multiple excellent properties such as high impedance, wear resistance, peel resistance, and self-healing properties, with outstanding durability. It has great application prospects in practical applications such as corrosion protection of marine engineering metals.

[0042] In a preferred embodiment of the method for preparing the shape memory superhydrophobic anticorrosive coating for marine metals of the present invention, in step (3), the mass ratio of oily epoxy resin to modified diatomaceous earth is 1:2-1:10 (e.g., 1:2, 1:4, 1:6, 1:8 or 1:10), the mass ratio of oily epoxy resin to curing agent is 2:1-1:1 (e.g., 2:1, 1.5:1 or 1:1), and the mass ratio of oily epoxy resin to the second solvent is 1:8-1:16 (e.g., 1:8, 1:10, 1:12, 1:14, 1:15 or 1:16); the second solvent is anhydrous ethanol. If too much modified diatomaceous earth is used, it will not be able to bond firmly to the surface of the fiber membrane. The modified diatomaceous earth in the cured superhydrophobic layer will easily fall off, so the coating cannot maintain its superhydrophobic properties for a long time. If the ratio of oil-based epoxy resin to curing agent is too high, the modified diatomaceous earth will be completely coated by the oil-based epoxy resin, and the superhydrophobicity of the coating will be reduced.

[0043] In a preferred embodiment of the method for preparing the shape memory superhydrophobic anticorrosive coating for marine metals of the present invention, during the preparation of modified diatomite, the mass-to-volume ratio of natural diatomite to a third solvent is 1:(11-12) (e.g., 1:11, 1:11.2, 1:11.4, 1:11.6, 1:11.8, or 1:12), the mass of natural diatomite is in g, and the volume of the third solvent is in mL; the first temperature is 35-60℃ (e.g., 35℃, 45℃, 55℃, or 60℃), the first time is 8-16h (e.g., 8h, 10h, 12h, 14h, or 16h); the second time is 6-12h (e.g., 6h, 8h, 10h, or 12h); and the third solvent is ethanol. In the process of modifying natural diatomaceous earth, the amount of solvent used affects the dispersion effect of natural diatomaceous earth and the concentration of octadecyltrimethoxysilane, which in turn affects the modification effect of natural diatomaceous earth. If the amount of the third solvent is inappropriate, the water contact angle of the shape memory superhydrophobic anticorrosive coating for marine metals of the present invention will decrease, and the hydrophobic performance will decline. When the ratio of natural diatomaceous earth to the third solvent is within the range defined in the preferred embodiment of the present invention, it helps to prepare a shape memory superhydrophobic anticorrosive coating for marine metals with a water contact angle of more than 150°. If the first temperature is too low, the hydrolysis condensation reaction will be incomplete, so the modification process will be slow and inefficient. If the first time is too short, the reaction will not be complete, thereby reducing the modification efficiency and the superhydrophobicity of the modified diatomaceous earth will not last. If the second stirring time at room temperature is too short, the stability of the modified diatomaceous earth will decrease, and it will not be able to provide superhydrophobicity for the coating for a long time.

[0044] In a preferred embodiment of the method for preparing the shape memory superhydrophobic anti-corrosion coating for marine metals of the present invention, the spinning solution is prepared by a method comprising the following steps: A. Mixing and stirring N,N-dimethylformamide and dichloromethane at a temperature of 18-25°C (e.g., 18°C, 20°C, 22°C or 25°C) and a humidity of 20%-30% (e.g., 20%, 24%, 26%, 28% or 30%) to obtain a first solvent; B. Adding polycaprolactone to the first solvent; C. Heating to 35-60°C (e.g., 35°C, 40°C, 45°C, 50°C, 55°C or 60°C) and continuing stirring for 12-18 hours (e.g., 12 hours, 14 hours, 16 hours or 18 hours) to obtain the spinning solution. In step C, the temperature (which should not be too high, as excessively high temperatures may cause polycaprolactone to fail and become unusable) and stirring time should be adjusted to ensure that polycaprolactone is fully dissolved and its dissolution rate is increased so that the spinning solution can meet the requirements of electrospinning.

[0045] In a preferred embodiment of the method for preparing the shape memory superhydrophobic anticorrosive coating for marine metals of the present invention, the first solvent comprises N,N-dimethylformamide and dichloromethane, wherein the mass ratio of N,N-dimethylformamide to dichloromethane is 1:1-1:6 (e.g., 1:1, 1:2, 1:3, 1:4, 1:5, or 1:6); and the mass ratio of polycaprolactone to the first solvent is (2-6):25 (e.g., 2:25, 3:25, 4:25, 5:25, or 6:25). The amount of the first solvent in the spinning solution and the ratio of N,N-dimethylformamide to dichloromethane in the first solvent affect the self-healing temperature of the nanofiber membrane obtained by electrospinning (specifically, the amount and ratio of the first solvent affect the solubility of polycaprolactone; since the polymer molecular chains are sufficiently large, changes in solubility inevitably affect the glass transition temperature of polycaprolactone; furthermore, the first solvent also affects the morphology of the fibers obtained by electrospinning).

[0046] In a preferred embodiment of the method for preparing the shape memory superhydrophobic anti-corrosion coating for marine engineering metals of the present invention, step (2) of preparing the nanofiber composite coating includes the following steps: fixing a syringe containing spinning solution onto an electrostatic coaxial spinning machine, connecting the coaxial needle to the positive and negative power supply, covering the collector with an aluminum foil, fixing the metal substrate coated with bisphenol A resin on the aluminum foil, and performing electrostatic spinning; the voltage of electrostatic spinning is 7-12kV (e.g., 7kV, 8kV, 10kV or 12kV). The push pump is pushed at a speed of 0.4-0.8 mm / min (e.g., 0.5 mm / min, 0.6 mm / min or 0.7 mm / min), and the spinning time is 20-40 min (e.g., 25 min, 30 min, 35 min or 40 min); electrospinning is carried out at a temperature of 18-25°C (e.g., 20°C, 22°C, 24°C, 26°C or 28°C) and a humidity of 20%-30% (e.g., 22%, 24%, 26%, 28% or 30%). In electrospinning, if the voltage is too low, the electrostatic force will be insufficient to stretch the polymer molecular chains into filaments, thus preventing normal electrospinning. If the voltage is too high, the spinning solution will not be fully stretched and will be collected as droplets on the roller. If the injection speed of the injection pump is too low, the spinning efficiency will decrease, and the spinning solution will easily solidify. If the injection speed is too high, the spinning solution will flow too fast and cannot be stretched into filaments under the action of the electric field. Spinning time affects the fiber membrane thickness; the shorter the spinning time, the thinner the membrane, and the longer the spinning time, the thicker the membrane.

[0047] In a preferred embodiment of the method for preparing the shape memory superhydrophobic anticorrosive coating for marine metals of the present invention, in step (3), the superhydrophobic coating solution is sprayed onto the surface of the nanofiber composite coating by air pressure spraying. The air pressure during air pressure spraying is 0.5-1.2 atm (e.g., 0.5 atm, 0.7 atm, 0.9 atm, 1.1 atm or 1.2 atm), the distance between the spray gun and the coating surface is 6-10 cm (e.g., 6 cm, 8 cm or 10 cm), the spraying time is 15-25 s (e.g., 15 s, 20 s or 25 s), and the number of spraying times is 1-3 times (e.g., 1 time, 2 times or 3 times). If the air pressure is too low, the modified diatomaceous earth particles cannot be sprayed onto the surface of the nanofiber composite coating; if the air pressure is too high, the pressure during spraying will be too high, which will damage the coating morphology.

[0048] In a preferred embodiment of the method for preparing the shape memory superhydrophobic anti-corrosion coating for marine metals of the present invention, the metal substrate is made of at least one of carbon steel, magnesium alloy, aluminum alloy, copper and titanium alloy.

[0049] The present invention also proposes a shape memory superhydrophobic anticorrosive coating for marine metals. The shape memory superhydrophobic anticorrosive coating for marine metals in the embodiments of the present invention is prepared by the method described above.

[0050] The shape memory superhydrophobic anticorrosion coating for marine metals of the present invention exhibits a high contact angle, a low sliding angle, and durable superhydrophobic properties. The nanofiber composite coating has a shape memory effect, and when the coating is damaged, it can be restored to its original surface morphology simply by heating the coating (which makes the shape memory superhydrophobic anticorrosion coating for marine metals of the present invention significantly reduce the contact area and contact time between the coating and water molecules during use, which is beneficial to preventing corrosive media from penetrating the coating).

[0051] The shape memory superhydrophobic anti-corrosion coating for marine metals of the present invention has a wide range of applications. After curing, it has good adhesion, water resistance, and salt water penetration resistance, and also has multiple self-healing properties. The process is simple, and it has excellent anti-corrosion effect and long-lasting protection.

[0052] Furthermore, the shape memory superhydrophobic anti-corrosion coating for marine metals of the present invention can be used in seawater environments above 50°C. In a preferred embodiment of the present invention, self-healing of the coating can be achieved by heating at 50°C for 2 hours. Therefore, if the shape memory superhydrophobic anti-corrosion coating for marine metals of the present invention is applied to a high-temperature seawater environment, it helps to achieve self-healing of the coating without heating it or reducing the heating pressure on the coating, thus better ensuring the protective effect of the coating on marine metals, improving the service life of marine metals, and reducing the maintenance frequency of the anti-corrosion coating for marine metals.

[0053] The present invention also provides a marine engineering metal device, wherein the surface of the marine engineering metal device of the present invention is provided with a shape memory superhydrophobic anti-corrosion coating as described above.

[0054] The following detailed description of the machine preparation method and application of the shape memory superhydrophobic anticorrosion coating for marine metals according to the present invention is provided through specific embodiments.

[0055] In the following embodiment:

[0056] The diatomaceous earth used had a particle size of 20±5μm; octadecyltrimethoxysilane (analytical grade) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; tetraethyl silicate (analytical grade), polycaprolactone (molecular weight 80000), bisphenol A diglycidyl ether (analytical grade), neopentyl glycol diglycidyl ether (analytical grade), and n-n-decylamine (analytical grade) were purchased from Shanghai Maclean Biochemical Co., Ltd.; E44 oil-based epoxy resin and low molecular weight polyamide curing agent (matching E44 oil-based epoxy resin) were purchased from Zhenjiang Danbao Resin Co., Ltd.; N,N-dimethylformamide (analytical grade), dichloromethane (analytical grade), anhydrous ethanol, and sodium chloride were purchased from Sinopharm Chemical Reagent Co., Ltd.; and Q235 carbon steel was purchased from Shandong Shengxin Technology Co., Ltd.

[0057] Example 1

[0058] This embodiment provides a method for preparing a shape memory superhydrophobic anti-corrosion coating for marine metals, comprising the following steps:

[0059] (1) Preparation of modified diatomaceous earth:

[0060] Weigh 5g of diatomaceous earth powder, dissolve it in 60mL of anhydrous ethanol and stir. After stirring evenly, add 2g of octadecyltrimethoxysilane and heat the mixture to 40℃. Stir for 8 hours and then stir at room temperature for 12 hours. Filter and wash three times with ethanol. Place the obtained powder in a 60℃ oven for 12 hours to obtain superhydrophobic powder (i.e., modified diatomaceous earth).

[0061] (2) Preparation of spinning solution:

[0062] Prepare 25g of a mixed solution at a temperature of 20℃ and a humidity of 25% (the mixed solution is obtained by stirring dichloromethane and N,N-dimethylformamide until they are mixed evenly; the mass ratio of dichloromethane to N,N-dimethylformamide in the mixed solution is 3:1).

[0063] Weigh 5g of polycaprolactone granules and add them to the above mixed solution (i.e., the first solvent). Adjust the temperature to 40℃ and continue stirring for 16 hours to obtain the spinning solution for later use.

[0064] (3) Preparation of nanofiber composite coating on carbon steel:

[0065] First, a resin coating is prepared by mixing bisphenol A diglycidyl ether, neopentyl glycol diglycidyl ether, and n-n-decylamine in a weight ratio of 2:1:1. The mixture is then uniformly coated onto a metal substrate (carbon steel) using a glass rod, and the coating is applied three times. The substrate is then placed in an oven at 40°C for 10 minutes until the coating reaches a surface dry state. At this point, the coating thickness is 40 μm.

[0066] Next, fix the syringe containing the spinning solution onto the electrostatic coaxial spinning machine, connect the coaxial needle to the positive and negative power supply, cover the collector with an aluminum foil, and fix the resin-coated carbon steel metal substrate on the aluminum foil; adjust the spinning voltage to 10kV, the push speed of the injection pump to 0.5mm / min, the temperature to 20℃, and the humidity to 30%; the spinning time is 45 minutes to obtain the nanofiber composite coating;

[0067] (4) Preparation of shape memory superhydrophobic anti-corrosion coating:

[0068] Weigh 2g of E44 oily epoxy resin and 1.5g of low molecular weight polyamide curing agent, dissolve them in 12g of anhydrous ethanol, stir for 20min, add 4g of modified diatomaceous earth, stir again for 20min, place the solution in a spray gun, and perform air pressure spraying on the surface of the nanofiber composite coating. The air pressure is 1atm, the spray gun is 12cm away from the coating surface, the spraying time is 15s, and the number of sprays is 3. Then place it in a 30℃ oven for 4h to finally obtain a shape memory superhydrophobic anti-corrosion coating with a final composite coating thickness of 70μm.

[0069] Example 2

[0070] This embodiment provides a method for preparing a shape memory superhydrophobic anti-corrosion coating. The only difference from Embodiment 1 is that the metal substrate is replaced by aluminum alloy instead of carbon steel; the other steps and parameters are the same as in Embodiment 1.

[0071] Example 3

[0072] The only difference between this embodiment and Example 1 is that the amount of ethanol solution used in step (1) is 15 mL; the rest is the same as in Example 1.

[0073] Example 4 The only difference between this example and Example 1 is that the amount of ethanol solution used in step (1) is 30 mL; the rest is the same as in Example 1.

[0074] Example 5

[0075] The only difference between this embodiment and Example 1 is that the amount of octadecyltrimethoxysilane used in step (1) is 0.5g; the rest are the same as in Example 1.

[0076] Example 6

[0077] The only difference between this embodiment and Example 1 is that the mass ratio of dichloromethane to N,N-dimethylformamide in the 25g mixed solution weighed in step (2) is 1:1; all other aspects are consistent with Example 1.

[0078] Example 7

[0079] The only difference between this embodiment and Example 1 is that the mass ratio of dichloromethane to N,N-dimethylformamide in the 25g mixed solution weighed in step (2) is 5:1; all other aspects are consistent with Example 1.

[0080] Tests showed that the self-healing temperature of the coating in this embodiment is above 70°C.

[0081] Example 8

[0082] The only difference between this embodiment and Example 1 is that the amount of polycaprolactone used in step (2) is 2g; the rest are the same as in Example 1.

[0083] Tests showed that the self-healing temperature of the coating in this embodiment is above 70°C.

[0084] Example 9

[0085] The only difference between this embodiment and Example 1 is that the amount of polycaprolactone used in step (2) is 6g; the rest are the same as in Example 1.

[0086] Tests showed that the self-healing temperature of the coating in this embodiment is above 70°C.

[0087] Example 10

[0088] The only difference between this embodiment and Example 1 is that the mass ratio of bisphenol A diglycidyl ether, neopentyl glycol diglycidyl ether and n-n-decylamine in step (3) is 1:1:1; the rest are the same as in Example 1.

[0089] Tests showed that the self-healing temperature of the coating in this embodiment is above 70°C.

[0090] Example 11

[0091] The only difference between this embodiment and Example 1 is that the mass ratio of bisphenol A diglycidyl ether, neopentyl glycol diglycidyl ether and n-n-decylamine in step (3) is 1:2:1; the rest are the same as in Example 1.

[0092] Tests showed that the self-healing temperature of the coating in this embodiment is above 70°C.

[0093] Example 12

[0094] The only difference between this embodiment and embodiment 1 is that the amount of modified diatomaceous earth used in step (4) is 1g; the rest are the same as in embodiment 1.

[0095] Example 13

[0096] The only difference between this embodiment and Example 1 is that the amount of low molecular weight polyamide curing agent used in step (4) is 0.8g; the rest are the same as in Example 1.

[0097] Comparative Example 1

[0098] This comparative example provides a method for preparing a pure resin coating, the steps of which are as follows:

[0099] To prepare the resin coating, bisphenol A diglycidyl ether, neopentyl glycol diglycidyl ether, and n-n-decylamine were mixed in a weight ratio of 2:1:1 and uniformly coated onto a metal substrate (carbon steel) using a glass rod. The coating was applied three times and then placed in an oven at 60°C for 20 minutes until it reached a surface dry state, thus obtaining a pure resin coating with a thickness of 43 μm.

[0100] Comparative Example 2

[0101] This comparative example provides a method for preparing a nanofiber composite coating. The only difference from Example 1 is that steps (1) and (4) are not involved. The other steps and parameters are the same as in Example 1.

[0102] Comparative Example 3

[0103] This comparative example provides a method for preparing a nanofiber composite coating. The only difference from Example 1 is that the preparation of the resin coating in step (3) is not involved (the bisphenol A epoxy resin and curing agent are not coated on the metal substrate). Instead, the electrospun fibers are directly collected on the metal substrate and then step (4) is performed. The other steps and parameters are the same as in Example 1.

[0104] Comparative Example 4

[0105] This comparative example provides a method for preparing a nanofiber composite coating. The only difference from Example 1 is that in step (4), oily epoxy resin and low molecular weight polyamide curing agent are not added. Instead, modified diatomaceous earth is directly dissolved in anhydrous ethanol and then sprayed with air pressure. Other steps and parameters are the same as in Example 1.

[0106] Application examples

[0107] The performance of the anti-corrosion coatings prepared in Example 1, Comparative Example 1, and Comparative Example 2 was tested:

[0108] 1) Scanning electron microscope (SEM) image

[0109] Each sample was sputter-coated with gold, and the surface was observed under a scanning electron microscope. Figure 1 ).in, Figure 1 (a) is a pure resin coating (i.e., Comparative Example 1), with a very smooth surface and no micro-nano structures can be observed; Figure 1 (b) is a nanofiber composite coating (Comparative Example 2). The intricate fibers can be clearly seen in the figure. The fibers have a relatively uniform diameter and form a good surface morphology. Figure 1 (c) is the morphology after spraying a superhydrophobic coating solution onto the surface of the nanofiber composite coating (Example 1). The disc-shaped structure characteristic of diatomaceous earth can be clearly seen. There are also pores on the surface of the disc. The entire surface presents a micro-nano layered structure, and the particles are aggregated.

[0110] 2) Concentrated confocal microscopy (CLSM)

[0111] The sample was placed under a laser confocal microscope to observe the surface roughness of the coating. Figure 2 ).in, Figure 2 (a) is the coating of Comparative Example 1, which has a very smooth surface with a roughness of 2.137 μm, and the coating is hydrophilic at this time; Figure 2 (b) is a nanofiber composite coating (Comparative Example 2), with sporadic protrusions on the surface, which is slightly rough. The fibers form a relatively rough surface with a roughness of 4.213 μm. At this time, the coating is hydrophilic. Figure 2 (c) is a shape memory superhydrophobic anti-corrosion coating (Example 1), with large particle protrusions on the surface. The coating surface exhibits a micro-nano structure, which is caused by the aggregation of diatomite particles. The roughness is significantly increased to 23.07 μm, at which point the coating exhibits superhydrophobicity.

[0112] 3) Wettability test

[0113] Figure 3 The diagram shows the water contact angles of the coatings obtained in Example 1 and Comparative Example 2 at different times; from Figure 2 and Figure 3 Combined analysis revealed that as the roughness of the coating increases, the water contact angle of the coating becomes larger. Figure 3 (b) shows the fiber composite coating prepared in Comparative Example 2. Its water contact angle was initially 65.4°, and decreased to 34.2° after 18 seconds of contact between the water droplet and the surface. This indicates that the coating is hydrophilic and the water droplet penetrates quickly. This is because the fiber surface has a large number of hydroxyl groups and a high porosity, which immediately combine with water molecules on the surface upon contact, thus exhibiting hydrophilicity.

[0114] and Figure 3The shape memory superhydrophobic anti-corrosion coating prepared in Example 1 of (a) initially had a water contact angle of 163.2°. After 40 minutes of contact with water molecules, the water contact angle decreased by only 4.1° to 159.1°, still exhibiting superhydrophobicity. At this point, the coating is a hydrophobic layer formed by combining the nanofiber composite coating prepared in Comparative Example 2 with a superhydrophobic coating solution (containing modified diatomaceous earth and oil-based resin). In general, Comparative Example 2 and Example 1 are inclusive; the lower layer of the shape memory superhydrophobic anti-corrosion coating of Example 1 is the nanofiber composite coating of Comparative Example 2. Therefore, the shape memory superhydrophobic anti-corrosion coating of Example 1 exhibits durable water repellency.

[0115] 4) Pull-out test

[0116] Figure 4 The peel adhesion strength of different coatings to the metal substrate was shown. Quantitatively, the adhesion strength of the pure resin coating (Comparative Example 1) was 0.21 MPa, while the adhesion strengths of the nanofiber composite coating (Comparative Example 2) and the shape memory superhydrophobic anti-corrosion coating (Example 1) to the steel plate were 0.29 MPa and 3.14 MPa, respectively. The results indicate that the coating formed by spraying a superhydrophobic coating solution containing modified diatomaceous earth and oily epoxy resin can effectively improve the overall adhesion strength of the coating to the metal substrate. Compared with other coatings, the adhesion strength improvement of Example 1 was more significant, which is related to the high compatibility and stable dispersion of the modified diatomaceous earth in the oily epoxy resin.

[0117] 5) Electrochemical impedance spectroscopy

[0118] A 3.5% NaCl solution was used as the electrolyte, a saturated silver / silver chloride electrode as the reference electrode, and a carbon rod as the counter electrode. The test amplitude was 10 mV, and the test frequency was 10 mV. -2 Hz-10 5 Hz, electrochemical impedance spectroscopy was performed using a Parstat P4000+ electrochemical workstation (results are shown in...). Figure 5 ).

[0119] Depend on Figure 5 (a)( Figure 5 (a) In the graph (where the horizontal axis is LogF, i.e., the logarithm of frequency; and the vertical axis is Log|Z|, i.e., the logarithm of modulus), it can be seen that after immersion for 45 days, the impedance of the shape memory superhydrophobic anti-corrosion coating (Example 1) can still reach 10. 10 Ω·cm 2 In this case, the coating still exhibits hydrophobicity, effectively preventing the penetration of water molecules and corrosive media, thus providing strong protection for the metal substrate. The impedance of the pure resin coating (Comparative Example 1) decreased to 10. 4 Ω·cm 2This is because pure resin coatings are hydrophilic and easily combine with water molecules, resulting in a large contact area. As the immersion time increases, water molecules and corrosive ions will penetrate into the metal surface through the micropores on the coating surface, causing metal corrosion. Once corrosion occurs, the coating will begin to peel off, gradually losing its protective ability.

[0120] Depend on Figure 5 (b1) and (b2) Figure 5 In (b1) and (b2): the horizontal axis is Zre, i.e., the real part; the vertical axis is -Zim, i.e., the negative number of the imaginary part. It can be seen that after immersion for 45 days, the radius of the capacitive arc of the shape memory superhydrophobic anti-corrosion coating (Example 1) is much larger than that of the pure resin coating (Comparative Example 1). This is because the shape memory superhydrophobic anti-corrosion coating (Example 1) itself has strong mechanical properties and excellent hydrophobic durability. Therefore, the anti-corrosion performance does not decrease significantly with the extension of immersion time. It can be seen that the shape memory superhydrophobic anti-corrosion coating (Example 1) has a significantly better protective ability against metal than the pure resin coating (Comparative Example 1).

[0121] 6) Abrasion resistance test

[0122] The abrasion resistance of the coating surface provided in Example 1 was measured by subjecting it to a 120-gram load of 600-grit sandpaper. Each abrasion cycle covered a distance of 25 cm, and a total of 100 cycles were performed. The test results are as follows: Figure 6 As shown. From Figure 6 As shown in (a1)-(a4), after 100 sandpaper abrasions, the loose nanoparticles deposited on the original surface were removed under mechanical linear motion, and larger protrusions were also smoothed out. The remaining nanoparticles on the surface were firmly adhered to the surface by the resin, indicating that the resin can tightly adhere the nanoparticles to the surface. These results demonstrate that the shape memory superhydrophobic anti-corrosion coating for marine metals provided in Example 1 has good wear resistance and can maintain excellent protective and superhydrophobic properties even under strong mechanical forces.

[0123] 7) Self-healing test

[0124] Figure 7Images (a) and (b) show CLSM images of the shape memory superhydrophobic anti-corrosion coating of Example 1 before and after repair of the cracked area at 50°C for 2 hours. In image (a), a crack is clearly visible on the coating surface, and the roughness on both sides of the crack is also affected. For the scratched coating surface, the scratch completely closes after heating, leaving only a small gap, and the deformed area around the scratch also essentially returns to its original morphology (b). This indicates that when heated above Tg (glass transition temperature), the fixed switching segment of the shape memory coating is reactivated and its entropic elastic behavior is restored, allowing the deformed micro / nanostructure to return to its original shape defined by chemical cross-linking (dots). Therefore, the introduction of the nanofiber composite coating endows the superhydrophobic coating with self-healing properties.

[0125] Figure 8 ( Figure 8 The numbers "1", "3", "5", "7", "9" and "12" outside the coordinate axis positions refer to the number of times damage / repair occurred; Figure 8 In (a): the horizontal axis is LogF, which is the logarithm of frequency; the vertical axis is Log|Z|, which is the logarithm of modulus. Figure 8 (b1) and (b2) show the EIS test results of the coating after damage and repair (the horizontal axis is Zre, i.e., the real part; the vertical axis is -Zim, i.e., the negative imaginary part). In addition to the coating's own corrosion inhibition effect, the corrosion resistance of the coating in this invention is also repaired through the thermally induced shape memory effect. The coating of Example 1 was first artificially damaged with a scalpel, then placed in a 50°C oven for 2 hours to heal (achieving repair of the damaged coating). Afterward, it was immersed in a 3.5wt% NaCl solution, and the corrosion resistance of the coating was studied using EIS testing.

[0126] At the start of immersion, the Bode plots (modulus Bode plots) of all coatings were characterized by a 45° straight line, |Z| 0.01Hz The value (i.e., the impedance value at a frequency of 0.01 Hz) reaches 2.5 × 10⁻⁶. 10 Ω·cm 2 The above demonstrates that the coating completely healed the damaged area through heat treatment after damage, thus restoring its anti-corrosion performance. This result is attributed to the thermally induced shape memory effect, where the damaged area was perfectly healed, almost identical to the coating before damage, and the recovery of the air film within the raised structure of the superhydrophobic surface. Experiments have shown that after 12 cycles of damage / repair, the coating's |Z| 0.01Hz The value remains at 10 10 Ω·cm 2The above results demonstrate that the coating prepared by this invention possesses multiple repair capabilities, exhibiting significant advantages compared to traditional single-layer, externally-assisted self-healing coatings. Even after 12 cycles of damage / repair, the coating maintains excellent corrosion resistance. Based on these results, it has been confirmed that the shape memory superhydrophobic anti-corrosion coating for marine metals of this invention can serve as a reliable barrier, providing stable and long-lasting superhydrophobicity.

[0127] 8) The adhesion strength, water contact angle, roughness and impedance of the coatings prepared in the examples and comparative examples were measured respectively, and the results are shown in Table 1 below.

[0128] Table 1

[0129]

[0130]

[0131] Notes: (1) Since the water contact angle of Examples 3-5 is much less than 150°, the adhesion strength and impedance of Examples 3-5 were not tested; (2) Since no oily epoxy resin was added to Comparative Example 4, the modified diatomaceous earth could not be bonded to the surface of the nanofiber composite coating. Therefore, the modified diatomaceous earth would fall off during the coating curing process, resulting in a decrease in the water contact angle, while the roughness did not change significantly; (3) The samples of Example 1 and Comparative Example 2 in Table 1 refer to those prepared by the methods of Example 1 and Comparative Example 2, respectively, and are similar to those of the nanofiber composite coating. Figure 3 The samples in Example 1 and Comparative Example 2 are located at different positions.

[0132] 9) The impedance of the coatings after damage / repair in Examples 1 and 2 was tested, and the test results are shown in Table 2 below:

[0133] Table 2

[0134]

[0135] Notes: (1) The samples of Examples 1 and 2 in Table 2 refer to the samples prepared by the methods of Examples 1 and 2 respectively, and located at different positions from Examples 1 and 2 in Table 1; (2) The experimental data in Table 2 are based on Figure 8 The result obtained after fitting.

[0136] In summary, the shape memory superhydrophobic anticorrosion coating for marine metals of the present invention has improved density, more uniform thickness and composition, and better compatibility with the metal substrate. It improves the poor mechanical properties of nanofiber membranes and endows the superhydrophobic coating with multiple self-healing properties. The shape memory superhydrophobic anticorrosion coating for marine metals of the present invention has excellent anticorrosion and mechanical properties, and provides better protection for the metal substrate.

[0137] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for the preparation of a shape memory superhydrophobic corrosion protective coating for marine metals, characterized by, The preparation method comprises the following steps: (1) Preparation of bisphenol A resin coating: The bisphenol A diglycidyl ether, neopentyl glycol diglycidyl ether and n-n-decylamine are mixed uniformly to obtain a resin coating solution, the resin coating solution is coated on a metal substrate, and after the resin coating solution reaches a tack-free state, a metal substrate coated with a bisphenol A resin coating is obtained; the mass ratio of the bisphenol A diglycidyl ether, neopentyl glycol diglycidyl ether and n-n-decylamine is (1-4):(1-3):1; (2) Preparation of nanofiber composite coating: Electrospinning is performed on the surface of the metal substrate coated with the bisphenol A resin coating to obtain the nanofiber composite coating; The components of the spinning solution for electrospinning include a first solvent and polycaprolactone; (3) Preparation of shape memory super-hydrophobic corrosion-resistant coating: The super-hydrophobic coating solution is sprayed on the surface of the nanofiber composite coating to obtain the shape memory super-hydrophobic corrosion-resistant coating; the components of the super-hydrophobic coating solution include modified diatomite, oily epoxy resin, curing agent and second solvent; The modified diatomite is prepared by the following method: natural diatomite is dispersed in a third solvent, after uniform stirring, octadecyltrimethoxysilane is added, first heated to a first temperature and stirred for a first time, then continuously stirred at room temperature for a second time, filtered, washed and dried to obtain the modified diatomite; the mass ratio of the natural diatomite to the octadecyltrimethoxysilane is 1:1-10:1; the mass-to-volume ratio of the natural diatomite to the third solvent is 1:(11-12), the mass of the natural diatomite is in grams, and the volume of the third solvent is in milliliters; the third solvent is ethanol; In step (3), the mass ratio of the oily epoxy resin to the modified diatomite is 1:2-1:10, the mass ratio of the oily epoxy resin to the curing agent is 2:1-1:1, and the mass ratio of the oily epoxy resin to the second solvent is 1:8-1:16; the second solvent is anhydrous ethanol.

2. The preparation method of the shape memory super-hydrophobic corrosion-resistant coating for marine metal according to claim 1, wherein the first temperature is 35-60 ℃, and the first time is 8-16 h; the second time is 6-12 h.

3. The method for preparing shape memory superhydrophobic corrosion protective coating for marine metals as claimed in claim 1 wherein, The spinning solution is prepared by the following method: A. N,N-dimethylformamide and dichloromethane are mixed and stirred at a temperature of 18-25 ℃ and a humidity of 20%-30% to obtain a first solvent; B. Polycaprolactone is added to the first solvent; C. The temperature is raised to 35-60 ℃, and the stirring is continued for 12-18 h to obtain the spinning solution.

4. The method for preparing a shape memory superhydrophobic corrosion protective coating for marine metals according to claim 3, wherein In the first solvent, the mass ratio of N,N-dimethylformamide to dichloromethane is 1:1-1:6; The mass ratio of the polycaprolactone to the first solvent is (2-6):

25.

5. The method for preparing shape memory superhydrophobic corrosion protective coating for marine metals as claimed in claim 1 wherein, In step (2), the preparation of the nanofiber composite coating comprises the following steps: fixing an injector containing a spinning solution on an electrostatic coaxial spinning machine, connecting the coaxial needle to a positive and negative power supply, covering an aluminum foil on the collector, fixing a metal substrate coated with a bisphenol A resin coating on the aluminum foil, and performing electrospinning; The voltage of the electrospinning is 7-12 kV, the pushing speed of the push pump is 0.4-0.8 mm / min, and the spinning time is 20-40 min. The electrospinning is performed under the condition that the humidity is 20%-30%.

6. The method for preparing shape memory superhydrophobic corrosion protective coating for marine metals as claimed in claim 1 wherein, In step (3), the super-hydrophobic coating solution is sprayed on the surface of the nanofiber composite coating by air pressure spraying, the air pressure during the air pressure spraying is 0.5-1.2 atm, the distance between the spray gun and the coating surface is 6-10 cm, the spraying time is 15-25 s, and the spraying frequency is 1-3 times.

7. The method for preparing a shape memory superhydrophobic corrosion protective coating for marine metals according to any one of claims 1-6, wherein, The material of the metal substrate is at least one of carbon steel, magnesium alloy, aluminum alloy, copper, and titanium alloy.

8. A shape memory superhydrophobic corrosion protective coating for marine metals characterized in that, The shape memory super-hydrophobic corrosion-resistant coating for marine metal is prepared by the method according to any one of claims 1-7.

9. A marine metal device, characterized by The surface of the marine metal equipment is provided with the shape memory super-hydrophobic corrosion-resistant coating according to claim 8.

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