Preparation method and application of a cyclic self-repairing intelligent anti-corrosion coating for intelligent detection sensors in harsh environments

Abstract

The present invention prepares a preparation method and application of a cyclic self-repairing intelligent anti-corrosion coating for a harsh environment intelligent detection sensor. Specifically: (1) preparing hollow silica micro-nanotubes; (2) preparing a chitosan-polyethylene oxide solution; (3) preparing a hollow silica micro-nanotube dispersion; (4) preparing a chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotube; (5) preparing a corrosion inhibitor filler; and (6) preparing a cyclic self-repairing intelligent anti-corrosion coating. The cyclic self-repairing intelligent anti-corrosion coating of the present invention has the characteristics of intelligent controlled-release corrosion inhibitor and cyclic self-repair. When the coating surface is corroded, the coating releases the corrosion inhibitor. After an oxide film is generated at the corrosion damage, the silica micro-nanotubes will re-coat the released corrosion inhibitor. After the oxide film is damaged, the corrosion inhibitor is released again, thereby achieving the effect of fully utilizing the corrosion inhibitor and effectively suppressing corrosion while saving the corrosion inhibitor.

Description

Technical Field

[0001] The present invention relates to a preparation method and application of a cyclic self-repairing intelligent anti-corrosion coating for an intelligent detection sensor in harsh environments, belonging to the technical field of metal corrosion protection. Background Art

[0002] Corrosion of intelligent detection sensors in harsh environments (such as the ocean, underground coal mines, and chemical industries) is linked to numerous factors, including improper sensor design, humidity, salinity, and pollutants. Long-term operation in harsh environments is a direct cause of sensor corrosion. Corrosion and contamination damage sensors result in inaccurate data, significantly shorten the service life of the equipment, and require extensive maintenance. Therefore, sensor corrosion prevention is crucial.

[0003] At present, the introduction of coatings and corrosion inhibitors with anti-corrosion properties is regarded as the most effective, lowest cost and most convenient option to prevent sensor corrosion. When certain local areas of the anti-corrosion coating are damaged during use, the sensor substrate will be exposed to the corrosive medium, leading to more serious corrosion problems. Traditional corrosion inhibitor anti-corrosion coatings use nanocontainers to load corrosion inhibitors. When corrosion occurs, the container releases the corrosion inhibitor to suppress the corrosion rate and achieve a self-repairing effect. Nanocontainers loaded with corrosion inhibitors can achieve uniform dispersion of the corrosion inhibitors in the coating. However, most existing external-aid self-repairing technologies are one-time repairs, which are mainly limited by the amount of corrosion inhibitors coated in the nanocontainers. Traditional nanocontainer-coated corrosion inhibitor anti-corrosion coatings have limitations. The corrosion inhibitors released by the nanocontainers are usually released in a one-time burst, and the corrosion inhibitors will be quickly exhausted, weakening the protective effect of the coating. Traditional intelligent anti-corrosion coatings usually need to be re-applied regularly to maintain their anti-corrosion effect, which increases maintenance costs and anti-corrosion workload.

[0004] Chinese patent document CN111234566A discloses an acid-base dual-responsive hollow mesoporous silica composite nanocontainer and a self-healing anti-corrosion coating. The ZIF-8 nanovalve coated on the nanocontainer prevents premature leakage of the corrosion inhibitor loaded into the nanocontainer. The acid-base dual-responsive self-healing anti-corrosion coating releases the corrosion inhibitor in response to changes in the ambient pH. However, the patent uses ZIF-8 nanovalves coated on the surface of the hollow mesoporous silica core, which is costly and has limitations.

[0005] Chinese patent document CN104927583A discloses a preparation method and application of a self-repairing intelligent anti-corrosion coating. L-histidine is adsorbed into silica microspheres as a corrosion inhibitor. Changes in environmental pH affect the charging properties of the silica microspheres and L-histidine. Under the action of electrostatic force, the silica microspheres release the corrosion inhibitor to suppress corrosion.

[0006] Chinese patent document CN113337210A discloses a preparation method and application of a pH-responsive silica nanocontainer composite silane film loaded with a corrosion inhibitor. Silica nanoparticles loaded with a corrosion inhibitor, 2-mercaptobenzothiazole, are added to a mixed solution of BTSE and KH-560 to obtain a pH-responsive silica nanocontainer composite silane film loaded with a corrosion inhibitor.

[0007] Chinese patent document CN109316606A discloses a method for preparing multi-level pH-responsive mesoporous silica composite nanoparticles. The method involves condensing silica modified with keto groups and a polymer containing hydrazide groups at the end to produce multi-level pH-responsive mesoporous silica composite nanoparticles. These multi-level pH-responsive mesoporous silica composite nanoparticles serve as carriers, effectively blocking pores. The acylhydrazone bonds connecting the pore-blocking agents in the composite nanoparticles cleave in response to acidic conditions, controlling the opening and closing of the pores. The morpholine groups intelligently regulate the surface charge of the composite nanoparticles, improving their dispersibility and stability.

[0008] However, the L-histidine-containing silica microspheres, corrosion inhibitor-loaded 2-mercaptobenzothiazole silica nanoparticles, and multi-stage pH-responsive mesoporous silica composite nanoparticles described in the aforementioned patents release active substances in a burst, essentially all at once, in response to environmental changes, failing to provide long-term corrosion protection. Furthermore, micro-damage to the coating develops gradually during service. In conventional intelligent repair coatings, the corrosion inhibitors in the micro-nano carriers are released prematurely, before the metal at the damaged site is exposed. Once the coating is damaged to the metal surface, the remaining corrosion inhibitors in the micro-nano containers are no longer able to provide adequate protection for the exposed metal substrate. Summary of the Invention

[0009] In response to the shortcomings of the existing technology, a preparation method and application of a cyclic self-repairing intelligent anti-corrosion coating for intelligent detection sensors in harsh environments are proposed.

[0010] The technical solutions of the present invention are as follows:

[0011] A method for preparing a cyclic self-repairing intelligent anti-corrosion coating for a harsh environment intelligent detection sensor comprises the following steps:

[0012] (1) Dissolving ferric chloride hexahydrate and urea in water, reacting at 100-150°C for 8-12 hours, cooling and washing, and calcining at 400-600°C for 1-4 hours to obtain nano-iron oxide; dissolving nano-iron oxide and hexadecyltrimethylammonium bromide in water by ultrasonication, adding ethyl orthosilicate and (3-mercaptopropyl)trimethoxysilane dropwise in sequence, stirring and reacting for 1-4 hours to obtain nano-iron oxide / silicon dioxide; dispersing nano-iron oxide / silicon dioxide in a mixture of hydrochloric acid and methanol, and reflux at 60-100°C for 18-26 hours to obtain hollow silica micro-nanotubes;

[0013] (2) dissolving chitosan in an acetic acid aqueous solution and stirring the mixture for 5 to 7 hours; then adding polyethylene oxide and continuing to stir the mixture for 20 to 40 minutes to obtain a chitosan-polyethylene oxide solution;

[0014] (3) dispersing the hollow silica micro-nanotubes obtained in step (1) into a phosphate buffer solution, adding 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, and stirring for 0.5 to 1.5 hours to obtain a hollow silica micro-nanotube dispersion;

[0015] (4) adding the hollow silica micro-nanotube dispersion obtained in step (3) to the chitosan-polyethylene oxide solution obtained in step (2), stirring and reacting for 12 to 36 hours, and obtaining chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotubes after centrifugation, washing and drying;

[0016] (5) dissolving the copper-based corrosion inhibitor in water and adjusting the pH to 2.0-4.0 to obtain a copper-based corrosion inhibitor solution; then adding the chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotubes obtained in step (4) to the copper-based corrosion inhibitor solution, ultrasonically treating for 1-3 hours, filtering, washing and drying to obtain the chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotube filler loaded with the copper-based corrosion inhibitor;

[0017] (6) The chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotube filler loaded with a copper-based corrosion inhibitor obtained in step (5) is added to the epoxy resin coating at a mass ratio of 12 to 20%, and stirred evenly to obtain a circulating self-repairing intelligent anti-corrosion coating.

[0018] Preferably, according to the present invention, in step (1), the mass volume ratio of ferric chloride hexahydrate, urea and water is (1-1.5): (0.5-1.5): 50, unit: g / g / mL.

[0019] Preferably, according to the present invention, in step (1), the mass volume ratio of the nano-ferric oxide, hexadecyltrimethylammonium bromide, ethyl orthosilicate and (3-mercaptopropyl)trimethoxysilane is (0.05-0.2): (0.5-1.5): (2-10): (0.5-1.5), unit: g / g / mL / mL.

[0020] Preferably, according to the present invention, in step (1), the mass volume ratio of the nano-ferric oxide / silicon dioxide, hydrochloric acid and methanol is (0.2-0.8): (5-15): (150-200), unit: g / mL / mL.

[0021] Preferably, according to the present invention, in step (2), the mass volume ratio of the chitosan, the acetic acid aqueous solution and the polyethylene oxide is (0.1-0.4):100:(1-4), unit: g / mL / g.

[0022] According to the present invention, preferably, in step (3), the mass volume ratio of the hollow silica micronanotubes, phosphate buffer, 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide is (0.05-0.15):20:(0.05-0.15):(0.02-0.08), unit: g / mL / g / g.

[0023] Preferably, according to the present invention, in step (4), the mass volume ratio of the hollow silica micro-nanotube dispersion and the chitosan-polyethylene oxide solution is (0.08-0.15): (10-40), unit: g / mL.

[0024] According to a preferred embodiment of the present invention, in step (5), the copper-based corrosion inhibitor is one or a mixture of 5-ethyl-1,3,4-thiadiazole-2-amine and 2-mercaptobenzothiazole.

[0025] Preferably, according to the present invention, in step (5), the mass volume ratio of the copper-based corrosion inhibitor to water is (0.04-0.08):100, unit: g / mL.

[0026] Preferably, according to the present invention, in step (5), the mass volume ratio of the chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotubes and the copper-based corrosion inhibitor solution is (0.08-0.15): (90-150), unit: g / mL.

[0027] The present invention provides a cyclic self-repairing intelligent anti-corrosion coating prepared by the above method.

[0028] The present invention also provides the application of the above-mentioned cyclic self-repairing intelligent anti-corrosion coating in the protection of ocean detection sensors.

[0029] Preferably, according to the present invention, the application is specifically: applying the cyclic self-repairing anti-corrosion coating to the surface of the ocean sensor, and drying and curing the coating for 15 to 30 days to form a cyclic self-repairing anti-corrosion coating with a thickness of 100 to 500 μm.

[0030] The technical features of the present invention are as follows:

[0031] The circulating self-repairing intelligent anti-corrosion coating prepared by the present invention belongs to the external aid type self-repairing coating, which uses a copper-based corrosion inhibitor as a repair agent, hollow silica micro-nanotubes that encapsulate the copper-based corrosion inhibitor as a self-repairing filler, and a deacetylated chitosan-polyethylene oxide copolymer that coats the hollow silica micro-nanotubes as an intelligent control switch for releasing the corrosion inhibitor, thereby realizing the cyclic self-repair of the corrosion-damaged coating. The copper-based corrosion inhibitor does not contain harmful heavy metals and is an environmentally friendly corrosion inhibitor. Compared with the traditional corrosion inhibitor anti-corrosion coating, the circulating self-repairing intelligent anti-corrosion coating provided by the present invention can intelligently control the release of the corrosion inhibitor to avoid rapid consumption of the corrosion inhibitor. At the same time, it can be repeatedly repaired under different pH environments, and has the characteristics of energy saving and high efficiency.

[0032] The technical features and beneficial effects of the present invention are as follows:

[0033] 1. The present invention synthesizes hollow silica micro-nanotubes that encapsulate copper-based corrosion inhibitors, and coats chitosan-polyethylene oxide copolymers on their surfaces to prepare a cyclic self-repairing intelligent anti-corrosion coating that can be repeatedly repaired. The cyclic self-repairing intelligent anti-corrosion coating uses chitosan and polyethylene oxide copolymers as a pH "switch" to release the encapsulated corrosion inhibitor, extending the cycle time of responsiveness to changes in microenvironmental pH, improving the controllability of the cyclic release of the corrosion inhibitor and the compatibility of the micro-nano container with the coating matrix, forming a protective measure for the cyclic release and controlled release of the corrosion inhibitor, and compensating for the performance defects of traditional self-repairing coatings. After the cyclic self-repairing intelligent anti-corrosion coating of the present invention is applied to the surface of the ocean detection sensor to form an anti-corrosion coating, the sensor's corrosion resistance and damage resistance are significantly improved.

[0034] 2. The cyclic self-repairing intelligent anti-corrosion coating prepared by the present invention has the characteristic of repeated repair under different pH environments. When the coating is damaged and the corrosive medium penetrates into the surface of the sensor substrate, the metal on the sensor surface undergoes anodic dissolution, the pH value of the anode micro-area decreases, and the amino groups of the deacetylated chitosan react with the H +The reaction results in protonation, raising the pH in the anode microregion and positively charging the cross-linked chitosan-polyethylene oxide copolymer. The positively charged chitosan-polyethylene oxide copolymer repel each other, causing it to expand and open the mesopores of the silica nanotubes, releasing the copper-based corrosion inhibitor. The copper-based corrosion inhibitor reacts with the active metal or metal ions on the sensor's metal surface, forming a dense protective film on the metal surface, effectively protecting the sensor. Once the protective film is formed, the amino groups of the chitosan deprotonate and re-coat the hollow silica nanotubes. After the protective film fails, the sensor surface metal comes into direct contact with the solution, and the self-healing process continues in a cycle until the copper-based corrosion inhibitor is completely consumed.

[0035] 3. The cyclic self-repairing intelligent anti-corrosion coating provided by this invention can significantly extend the service life of intelligent detection sensors. The service life of detection sensors is closely related to their damage resistance and corrosion resistance. The cyclic self-repairing intelligent anti-corrosion coating can effectively improve the corrosion and damage resistance of detection sensors.

[0036] 4. The circulating self-repairing intelligent anti-corrosion coating provided by the present invention is non-toxic, low-priced, and has mild configuration conditions. The coating can be released repeatedly, which makes the utilization rate of the coating corrosion inhibitor high. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is the SEM image of the cyclic self-repairing intelligent anti-corrosion coating of the present invention.

[0038] Figure 2 This is the SEM image of the traditional corrosion inhibitor anti-corrosion coating in comparative example 1.

[0039] Figure 3 It is the impedance modulus of the cyclic self-repairing intelligent anti-corrosion coating of the present invention after being immersed in a 3.5% NaCl solution for 30 days.

[0040] Figure 4 This is the impedance modulus of the traditional corrosion inhibitor anti-corrosion coating in comparative example 1 after being immersed in a 3.5% NaCl solution for 30 days.

[0041] Figure 5 This is the impedance Nyquist diagram of the cyclic self-repairing anti-corrosion coating of the present invention immersed in 3.5% NaCl solution for 30 days.

[0042] Figure 6 This is the impedance Bode diagram of the cyclic self-repairing anti-corrosion coating of the present invention immersed in 3.5% NaCl solution for 30 days. DETAILED DESCRIPTION

[0043] The technical solution of the present invention will be further described below with reference to the embodiments, but the protection scope of the present invention is not limited thereto.

[0044] The experimental methods described in the following examples are conventional methods unless otherwise specified; the epoxy resin coatings and other reagent components and equipment are all commercially available unless otherwise specified.

[0045] Example 1

[0046] A method for preparing a cyclic self-repairing intelligent anti-corrosion coating for a harsh environment intelligent detection sensor comprises the following steps:

[0047] (1) 1.08 g of ferric chloride hexahydrate and 1 g of urea were dissolved in 50 mL of water, transferred to a 120 ° C autoclave and kept warm for 10 h. After cooling to room temperature, the mixture was washed with water and ethanol for separation, and then calcined at 500 ° C for 2 h to obtain nano-iron oxide; 0.1 g of nano-iron oxide and 1 g of hexadecyltrimethylammonium bromide were ultrasonically dissolved in water, 5 mL of ethyl orthosilicate and 0.97 mL of (3-mercaptopropyl)trimethoxysilane were added dropwise, and magnetic stirring was performed for 2 h to obtain nano-iron oxide / silicon dioxide; 0.4 g of nano-iron oxide / silicon dioxide was dispersed in a mixture of 9 mL of hydrochloric acid and 160 mL of methanol, and refluxed at 75 ° C for 24 h to obtain silicon dioxide micro-nanotubes;

[0048] (2) 0.2 g of chitosan was dissolved in 100 mL of acetic acid aqueous solution, and magnetic stirring was performed for 6 h. Then 2 g of polyethylene oxide was added and stirring was continued for 30 min to obtain a chitosan-polyethylene oxide solution;

[0049] (3) Dispersing 100 mg of the hollow silica micro-nanotubes obtained in step (1) into 20 mL of phosphate buffered saline, adding 100 mg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 60 mg of N-hydroxysuccinimide, and stirring continuously for 1 h to obtain a hollow silica micro-nanotube dispersion;

[0050] (4) adding 100 mg of the hollow silica micro-nanotube dispersion obtained in step (3) to 20 mL of the chitosan-polyethylene oxide solution obtained in step (2), stirring for 24 h, first centrifuging, then washing with water and ethanol, and finally drying in an air atmosphere for 24 h to obtain chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotubes;

[0051] (5) 50 mg of 5-ethyl-1,3,4-thiadiazole-2-amine was dissolved in 100 mL of water, and the pH was adjusted to 3.0 with hydrochloric acid to obtain a 5-ethyl-1,3,4-thiadiazole-2-amine solution; then 100 mg of the chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotubes obtained in step (4) was added to 100 mL of the 5-ethyl-1,3,4-thiadiazole-2-amine solution, ultrasonically treated for 2 h, first centrifuged, then washed with water and ethanol, and finally placed in a forced air drying oven at 30° C. for 48 h to obtain a chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotube filler loaded with 5-ethyl-1,3,4-thiadiazole-2-amine;

[0052] (6) The chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotube filler loaded with 5-ethyl-1,3,4-thiadiazole-2-amine obtained in step (5) is added to the epoxy resin coating at a mass ratio of 14%, and stirred evenly to obtain a circulating self-repairing intelligent anti-corrosion coating.

[0053] Example 2

[0054] A method for preparing a cyclic self-repairing intelligent anti-corrosion coating for a harsh environment intelligent detection sensor comprises the following steps:

[0055] (1) 1.32 g of ferric chloride hexahydrate and 1.2 g of urea were dissolved in 50 mL of water, transferred to a 140 ° C autoclave and kept warm for 12 h. After cooling to room temperature, the mixture was washed with water and ethanol for separation, and then calcined at 600 ° C for 3 h to obtain nano-iron oxide; 0.15 g of nano-iron oxide and 1.2 g of hexadecyltrimethylammonium bromide were ultrasonically dissolved in water, 7 mL of ethyl orthosilicate and 1.25 mL of (3-mercaptopropyl)trimethoxysilane were added dropwise, and magnetic stirring was performed for 2 h to obtain nano-iron oxide / silicon dioxide; 0.6 g of nano-iron oxide / silicon dioxide was dispersed in a mixture of 12 mL of hydrochloric acid and 180 mL of methanol, and refluxed at 75 ° C for 24 h to obtain silicon dioxide micro-nanotubes;

[0056] (2) 0.3 g of chitosan was dissolved in 100 mL of acetic acid aqueous solution and stirred magnetically for 6 h. Then 3 g of polyethylene oxide was added and stirred for 30 min to obtain a chitosan-polyethylene oxide solution.

[0057] (3) Dispersing 130 mg of the hollow silica micro-nanotubes obtained in step (1) into 20 mL of phosphate buffered saline, adding 80 mg of 1-ethyl-(3-dimethylaminopropyl)carbodiimide and 40 mg of N-hydroxysuccinimide, and stirring continuously for 1 h to obtain a hollow silica micro-nanotube dispersion;

[0058] (4) adding 120 mg of the hollow silica micro-nanotube dispersion obtained in step (3) to 30 mL of the chitosan-polyethylene oxide solution obtained in step (2), stirring for 24 h, first centrifuging, then washing with water and ethanol, and finally drying in an air atmosphere for 24 h to obtain chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotubes;

[0059] (5) 60 mg of 2-mercaptobenzothiazole was dissolved in 125 mL of water and the pH was adjusted to 3.0 with hydrochloric acid to obtain a 2-mercaptobenzothiazole solution; then 150 mg of the chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotubes obtained in step (4) was added to 125 mL of the 2-mercaptobenzothiazole solution, ultrasonically treated for 2 h, centrifuged, washed with water and ethanol, and finally placed in a forced air drying oven at 30° C. for 48 h to obtain a chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotube filler loaded with 2-mercaptobenzothiazole;

[0060] (6) The chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotube filler loaded with 2-mercaptobenzothiazole obtained in step (5) is added to the epoxy resin coating at a mass ratio of 18%, and stirred evenly to obtain a circulating self-repairing intelligent anti-corrosion coating.

[0061] Comparative Example 1

[0062] A method for preparing a conventional corrosion inhibitor anticorrosive coating comprises the following steps:

[0063] (1) 1.08 g of ferric chloride hexahydrate and 1 g of urea were dissolved in 50 mL of water, transferred to a 120 ° C autoclave and kept warm for 12 h. After cooling to room temperature, the mixture was washed with water and ethanol for separation, and then calcined at 500 ° C for 2 h to obtain nano-iron oxide; 0.1 g of nano-iron oxide and 1 g of hexadecyltrimethylammonium bromide were ultrasonically dissolved in water, 5 mL of ethyl orthosilicate and 0.97 mL of (3-mercaptopropyl)trimethoxysilane were added dropwise, and magnetic stirring was performed for 2 h to obtain nano-iron oxide / silicon dioxide; 0.4 g of nano-iron oxide / silicon dioxide was dispersed in a mixture of 9 mL of hydrochloric acid and 160 mL of methanol, and refluxed at 75 ° C for 24 h to obtain silicon dioxide micro-nanotubes;

[0064] (2) 50 mg of 5-ethyl-1,3,4-thiadiazole-2-amine was dissolved in 100 ml of ethanol and stirred for 30 min to obtain a 5-ethyl-1,3,4-thiadiazole-2-amine solution; then 0.4 g of silica micro-nanotubes was added to the 5-ethyl-1,3,4-thiadiazole-2-amine solution, ultrasonically dispersed for 30 min, magnetically stirred for 48 h, and then the mixture was centrifuged and washed. The product was vacuum dried at 80 ° C for 48 h to obtain a silica micro-nanotube coating coated with 5-ethyl-1,3,4-thiadiazole-2-amine.

[0065] Experimental example

[0066] 1. The SEM photo of the cyclic self-repairing intelligent anti-corrosion coating of Example 1 of the present invention is as follows: Figure 1 The SEM photo of the traditional corrosion inhibitor anticorrosive coating prepared in Comparative Example 1 is shown in FIG. Figure 2 shown.

[0067] Depend on Figure 1 It can be seen that the chitosan-polyethylene oxide copolymer in the cyclic self-repairing intelligent anti-corrosion coating of the present invention has achieved surface functionalization of silica micro-nanotubes.

[0068] contrast Figure 1 and Figure 2 It can be seen that the silica micro-nanotubes coated with the chitosan-polyethylene oxide copolymer in the circulating self-repairing intelligent anti-corrosion coating of the present invention are intact and fully encapsulated. This shows that the chitosan-polyethylene oxide copolymer can improve the encapsulation capacity of silica micro-nanotubes. Compared with traditional corrosion inhibitor anti-corrosion coatings, the chitosan-polyethylene oxide copolymer in the circulating self-repairing intelligent anti-corrosion coating of the present invention can increase the corrosion inhibitor loading capacity of silica micro-nanotubes, thereby increasing the service life of the anti-corrosion coating.

[0069] 2. The cyclic self-repairing intelligent anti-corrosion coating prepared in Example 1 and the traditional corrosion inhibitor anti-corrosion coating prepared in Comparative Example 1 were coated on the surface of the ocean detection sensor with a thickness of 150 μm and cured for 30 days to form a cyclic self-repairing intelligent anti-corrosion coating and a traditional anti-corrosion coating. Then, the electrochemical impedance spectroscopy technique was used to study the response behavior of the coatings formed by the two groups of coatings to copper in a 3.5% NaCl solution using a three-electrode system. Specifically, the impedance modulus of the coating generated by the cyclic self-repairing intelligent anti-corrosion coating of the present invention and the coating generated by the traditional corrosion inhibitor anti-corrosion coating were measured at 0, 3, 10, 20, and 30 days respectively. The results are as follows: Figures 3-4 The impedance Nyquist spectrum and impedance Bode spectrum of the coating generated by the self-repairing intelligent anti-corrosion coating of the present invention in 3.5% NaCl solution were measured at 0, 3, 10, 20, and 30 days. The results are shown in Figure 2. Figure 6 shown.

[0070] Depend on Figure 3 It can be seen that the impedance modulus of the cyclic self-repairing intelligent anti-corrosion coating of the present invention first increases and then decreases around 6d and 25d.

[0071] Depend on Figure 4 It can be seen that the impedance modulus of traditional corrosion inhibitor anti-corrosion coatings shows a continuous downward trend.

[0072] Depend on Figure 5 and Figure 6 It can be seen that as the number of immersion days increases, the capacitance arc of the cyclic self-repairing intelligent anti-corrosion coating of the present invention increases, reaching a maximum at 6 days, indicating that the deacetylated chitosan-polyethylene oxide copolymer expands and opens the mesopores of the silica micro-nanotubes, releasing corrosion inhibitors to inhibit corrosion. Then the capacitance arc of the cyclic self-repairing intelligent anti-corrosion coating of the present invention continues to decrease, and the deacetylated chitosan-polyethylene oxide copolymer re-coats the silica micro-nanotubes. At 25 days, the capacitance arc increases again, indicating that the cyclic self-repairing intelligent anti-corrosion coating of the present invention releases corrosion inhibitors again, achieving the effect of cyclic self-repair, and then the coating capacitance arc continues to decrease until 30 days.

Claims

1. A method for preparing a cyclic self-repairing intelligent anti-corrosion coating for a harsh environment intelligent detection sensor, characterized in that: The steps are as follows: (1) Dissolving ferric chloride hexahydrate and urea in water, reacting at 100-150°C for 8-12 hours, cooling and washing, and calcining at 400-600°C for 1-4 hours to obtain nano-iron oxide; dissolving nano-iron oxide and hexadecyltrimethylammonium bromide in water by ultrasonication, adding ethyl orthosilicate and (3-mercaptopropyl)trimethoxysilane dropwise in sequence, stirring and reacting for 1-4 hours to obtain nano-iron oxide / silicon dioxide; dispersing nano-iron oxide / silicon dioxide in a mixture of hydrochloric acid and methanol, and reflux at 60-100°C for 18-26 hours to obtain hollow silica micro-nanotubes; (2) dissolving chitosan in an acetic acid aqueous solution and stirring the mixture for 5 to 7 hours; then adding polyethylene oxide and continuing to stir the mixture for 20 to 40 minutes to obtain a chitosan-polyethylene oxide solution; (3) dispersing the hollow silica micro-nanotubes obtained in step (1) into a phosphate buffer solution, adding 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide, and stirring for 0.5 to 1.5 hours to obtain a hollow silica micro-nanotube dispersion; (4) adding the hollow silica micro-nanotube dispersion obtained in step (3) to the chitosan-polyethylene oxide solution obtained in step (2), stirring and reacting for 12 to 36 hours, and obtaining chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotubes after centrifugation, washing and drying; (5) dissolving the copper-based corrosion inhibitor in water and adjusting the pH to 2.0-4.0 to obtain a copper-based corrosion inhibitor solution; then adding the chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotubes obtained in step (4) to the copper-based corrosion inhibitor solution, ultrasonically treating for 1-3 hours, filtering, washing and drying to obtain the chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotube filler loaded with the copper-based corrosion inhibitor; (6) The chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotube filler loaded with a copper-based corrosion inhibitor obtained in step (5) is added to the epoxy resin coating at a mass ratio of 12 to 20%, and stirred evenly to obtain a circulating self-repairing intelligent anti-corrosion coating.

2. The preparation method according to claim 1, wherein In step (1), the mass volume ratio of the ferric chloride hexahydrate, urea and water is (1-1.5): (0.5-1.5): 50, unit: g / g / mL.

3. The preparation method according to claim 1, wherein In step (1), the mass volume ratio of the nano-ferric oxide, hexadecyltrimethylammonium bromide, ethyl orthosilicate and (3-mercaptopropyl)trimethoxysilane is (0.05-0.2): (0.5-1.5): (2-10): (0.5-1.5), unit: g / g / mL / mL.

4. The preparation method according to claim 1, wherein In step (1), the mass volume ratio of the nano-ferric oxide / silicon dioxide, hydrochloric acid and methanol is (0.2-0.8): (5-15): (150-200), unit: g / mL / mL.

5. The preparation method according to claim 1, wherein In step (2), the mass volume ratio of the chitosan, the acetic acid aqueous solution and the polyethylene oxide is (0.1-0.4):100:(1-4), unit: g / mL / g.

6. The preparation method according to claim 1, wherein In step (3), the mass volume ratio of the hollow silica micronanotubes, phosphate buffer, 1-ethyl-(3-dimethylaminopropyl)carbodiimide and N-hydroxysuccinimide is (0.05-0.15):20:(0.05-0.15):(0.02-0.08), unit: g / mL / g / g.

7. The preparation method according to claim 1, wherein In step (4), the mass volume ratio of the hollow silica micro-nanotube dispersion and the chitosan-polyethylene oxide solution is (0.08-0.15): (10-40), unit: g / mL.

8. The preparation method according to claim 1, wherein In step (5), the copper-based corrosion inhibitor is one or a mixture of 5-ethyl-1,3,4-thiadiazole-2-amine and 2-mercaptobenzothiazole; The mass volume ratio of the copper-based corrosion inhibitor to water is (0.04-0.08):100, unit: g / mL; The mass volume ratio of the chitosan-polyethylene oxide copolymer-coated hollow silica micro-nanotubes and the copper-based corrosion inhibitor solution is (0.08-0.15): (90-150), unit: g / mL.

9. A circulating self-repairing intelligent anti-corrosion coating, characterized in that: It is prepared according to the method according to any one of claims 1 to 8.

10. Application of the cyclic self-repairing intelligent anti-corrosion coating according to claim 9 in the protection of ocean detection sensors; The application is specifically: applying a cyclic self-repairing anti-corrosion coating to the surface of an ocean sensor, and drying and curing the coating for 15 to 30 days to form a cyclic self-repairing anti-corrosion coating with a thickness of 100 to 500 μm.

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