A gradient anti-fouling coating on the surface of a titanium alloy, a preparation method and an application

Abstract

The present invention belongs to the technical field of anti-fouling on alloy surfaces, and discloses a gradient anti-fouling coating on a titanium alloy surface, a preparation method and an application thereof. The gradient anti-fouling coating on the titanium alloy surface successively includes a titanium alloy substrate, an oxide coating, and a brush-shaped polymer coating from bottom to top; the oxide coating contains a metal bactericide precursor; the brush-shaped polymer coating contains polydimethylsiloxane. The gradient anti-fouling coating on the titanium alloy surface has a gradient anti-fouling function, and can effectively solve the problems of biological fouling formed by the attachment of small fouling organisms such as bacteria and large microorganisms such as algae and the resulting firm large biological fouling that cannot be avoided simultaneously by the coatings prepared in the prior art.

Description

Technical Field

[0001] The present invention belongs to the technical field of anti-fouling on alloy surfaces, and particularly relates to a gradient anti-fouling coating on the surface of a titanium alloy, a preparation method thereof, and an application thereof. Background Art

[0002] Due to its excellent corrosion resistance and mechanical properties, titanium alloy is known as the "marine metal" and is widely used in marine facilities, such as deep-sea submersibles, ship components, hydrocarbon extraction devices, heat exchangers, and condenser tubes. On the other hand, the problem of biofouling caused by the attachment and accumulation of microorganisms, arthropods, and mollusks on the material surface has caused huge economic losses and threatens the service safety of marine facilities. Worse still, titanium alloy has a high degree of biocompatibility and suffers from the problem of biofouling more severely than other structural materials, which seriously damages its long-term service safety and performance. In other words, the problem of biofouling is a huge obstacle to the large-scale application of titanium alloy in the marine environment.

[0003] Anti-biofouling coatings that repel or kill attached organisms on various materials are widely used on various materials, including titanium alloy, steel, aluminum alloy, etc. Traditional coatings are mainly based on organotin. Although these coatings have good anti-fouling effects, they are harmful to all marine organisms, and the contaminated seafood and marine environment will ultimately affect our daily life and health. This major drawback runs counter to the growing global consensus on environmental protection, and many countries have taken action to ban such toxic anti-fouling coatings. Some fungicidal coatings replacing organotin have been continuously developed, such as zinc-based coatings. In addition, some coatings like superhydrophobic coatings, as an emerging technology, can significantly reduce the surface energy of various materials, such as titanium alloy, zinc, steel, polyvinylidene fluoride, etc., and can effectively capture a layer of air underwater to serve as a barrier for isolating biofouling. However, after being immersed in water for a period of time, the captured air will eventually detach or dissolve in water, and the anti-biofouling performance of the superhydrophobic surface will degrade significantly. In addition, these coatings replacing organotin and superhydrophobic surfaces, due to being solid surfaces, cannot prevent the attachment and accumulation of biological macromolecules (such as proteins, polysaccharides, and dead microorganisms) on the material. These organic substances such as biological macromolecules can provide rich nutrients and attract organisms, which will greatly accelerate biofouling.

[0004] Therefore, there is an urgent need to provide a new anti-fouling coating on the surface of a titanium alloy, which can greatly reduce marine biofouling. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. For this purpose, the present invention provides a gradient antifouling coating on the surface of a titanium alloy, a preparation method thereof, and an application. The present invention uses an oxidation reaction to prepare an oxide coating containing a metal bactericide on the surface of the titanium alloy, and then activates the surface of the oxide coating and in-situ grafts a brush polymer coating to obtain a firm and durable gradient antifouling coating. It solves the problems of biofouling films formed by the attachment of small fouling such as biological macromolecules and biological remains that cannot be avoided by the antifouling coatings in the prior art, and the resulting firm large-scale biological fouling.

[0006] The first aspect of the present invention provides a gradient antifouling coating on the surface of a titanium alloy.

[0007] Specifically, a gradient antifouling coating on the surface of a titanium alloy sequentially includes a titanium alloy substrate, an oxide coating, and a brush polymer coating from bottom to top;

[0008] The oxide coating contains a metal bactericide;

[0009] The brush polymer coating contains polydimethylsiloxane.

[0010] Preferably, the polydimethylsiloxane includes at least one of linear terminal olefin polydimethylsiloxane, linear alkyl-terminated polydimethylsiloxane, and linear hydroxyl-terminated polydimethylsiloxane.

[0011] Preferably, the metal bactericide is selected from bactericide precursors containing at least one of copper, zinc, strontium, chromium, or tungsten.

[0012] Preferably, the bactericide precursor is selected from oxide bactericides containing at least one of copper, zinc, strontium, chromium, or tungsten.

[0013] Preferably, the titanium alloy substrate includes any one of TA1, TA2, and TC4. The titanium alloy in the present invention includes pure titanium or an alloy composed of titanium and other elements.

[0014] The second aspect of the present invention provides a preparation method of a gradient antifouling coating on the surface of a titanium alloy.

[0015] Specifically, a preparation method of a gradient antifouling coating on the surface of a titanium alloy includes the following steps:

[0016] Using an oxidation reaction, an oxide coating is prepared on the titanium alloy substrate, and then activation treatment is performed to obtain a sample, and the sample is then subjected to a chemical reaction with polydimethylsiloxane to obtain the gradient antifouling coating on the surface of the titanium alloy.

[0017] Preferably, before preparing the oxide coating, the titanium alloy substrate is cleaned.

[0018] Preferably, the cleaning is sequentially performed with acetone, ethanol, and deionized water.

[0019] Preferably, the oxidation reaction is selected from at least one of micro-arc oxidation, anodic oxidation, electrochemical deposition, and thermal oxidation.

[0020] Preferably, the process of the micro-arc oxidation method is as follows: placing the electrolyte in an electrolytic cell, then placing the titanium alloy substrate in the electrolyte, and performing micro-arc oxidation treatment using a bipolar pulse micro-arc oxidation power supply; the composition of the electrolyte includes sodium silicate, alkali, potassium fluoride, a fungicide precursor, and water; the fungicide precursor is selected from metal complexes or metal salts containing at least one of copper, zinc, strontium, chromium, or tungsten.

[0021] More preferably, the process of the micro-arc oxidation method is as follows: placing the electrolyte in an electrolytic cell, then placing the titanium alloy substrate in the electrolyte, performing micro-arc oxidation treatment using a bipolar pulse micro-arc oxidation power supply, then cleaning and drying; the composition of the electrolyte, by weight, includes 400-500 parts of sodium silicate, 30-80 parts of alkali, 80-120 parts of potassium fluoride, 15-45 parts of the fungicide precursor, and 250-400 parts of water.

[0022] Preferably, the activation treatment includes at least one of oxygen plasma treatment and toluene cleaning activation treatment.

[0023] Preferably, the process of the chemical reaction of polydimethylsiloxane includes at least one of sulfuric acid-catalyzed polydimethylsiloxane polymerization reaction method, thermal equilibrium polydimethylsiloxane chemical polymerization reaction method, atom transfer radical polymerization reaction method, and thiol-ene chemical polymerization reaction method.

[0024] Preferably, the process of the thermal equilibrium polydimethylsiloxane chemical polymerization reaction method is as follows: placing the sample in a reaction vessel, immersing the sample with polydimethylsiloxane, reacting in an oven, the reaction time is 10-40 hours, and the reaction temperature is 60°C-180°C.

[0025] More preferably, the process of the thermal equilibrium polydimethylsiloxane chemical polymerization reaction method is as follows: placing the sample in a reaction vessel, immersing the sample with polydimethylsiloxane, reacting in an oven, the reaction time is 12-36 hours, and the reaction temperature is 80°C-180°C.

[0026] The third aspect of the present invention provides an application of a titanium alloy surface gradient anti-fouling coating.

[0027] A device includes the above-mentioned titanium alloy surface gradient anti-fouling coating.

[0028] Preferably, the device includes at least one of marine equipment, aviation equipment, biomedical equipment, land transportation vehicles, and sports goods.

[0029] The application of the above-mentioned gradient anti-fouling coating on the titanium alloy surface in the fields of anti-corrosion or anti-fouling.

[0030] Preferably, the application includes the application in the preparation of marine equipment, aviation equipment, biomedical equipment, land transportation vehicles, and cultural and sports goods.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] (1) The gradient anti-fouling coating on the titanium alloy surface of the present invention uses environmentally friendly and low-surface-energy polydimethylsiloxane as the anti-fouling group, which is low in cost and environmentally friendly;

[0033] (2) The oxide coating and brush-like polymer coating in the gradient anti-fouling coating on the titanium alloy surface of the present invention have high adhesion to the titanium alloy substrate and high wear resistance;

[0034] (3) The gradient anti-fouling coating on the titanium alloy surface of the present invention has a gradient anti-fouling function, which can effectively solve the problems of biofouling formed by the attachment of small fouling organisms such as bacteria and large microorganisms such as algae that cannot be avoided simultaneously in the coatings prepared in the prior art and the resulting firm large-scale biofouling;

[0035] (4) The gradient anti-fouling coating on the titanium alloy surface of the present invention can be used for anti-corrosion or anti-fouling in marine equipment, aviation equipment, biomedical equipment, land transportation vehicles, and cultural and sports goods. Description of the Drawings

[0036] Figure 1 The surface morphology diagram of the product prepared in Comparative Example 1;

[0037] Figure 2 The surface morphology diagram of the product prepared in Comparative Example 2;

[0038] Figure 3 The infrared spectrum diagram of the gradient anti-fouling coating on the titanium alloy surface prepared in Example 1;

[0039] Figure 4 The statistical chart of the amount of Chlorella vulgaris attached to the surface after a 7-day Chlorella vulgaris attachment experiment on titanium alloy, the product prepared in Comparative Example 2, and the gradient anti-fouling coating on the titanium alloy surface prepared in Example 1;

[0040] Figure 5 The anti-Escherichia coli effect diagrams of Comparative Example 3 and the gradient anti-fouling coating on the titanium alloy surface prepared in Example 1. Detailed Embodiments

[0041] In order to make those skilled in the art more clearly understand the technical solutions described in the present invention, the following examples are listed for illustration. It should be noted that the following examples do not limit the scope of protection required by the present invention.

[0042] Unless otherwise specified, the raw materials, reagents or devices used in the following examples can be obtained from conventional commercial channels or can be obtained by existing known methods.

[0043] Example 1

[0044] A gradient anti-fouling coating on the surface of a titanium alloy, from bottom to top, sequentially includes a titanium alloy substrate, an oxide coating, and a brush-shaped polymer coating;

[0045] The oxide coating contains copper oxide.

[0046] The brush-shaped polymer coating contains polydimethylsiloxane.

[0047] A method for preparing a gradient anti-fouling coating on the surface of a titanium alloy, comprising the following steps,

[0048] Take titanium alloy (TA2), ultrasonically clean it with acetone, ethanol, and deionized water in sequence for 40 minutes, vacuum dry it, then use an oxidation reaction to prepare an oxide coating on the titanium alloy substrate, then perform a toluene cleaning and activation treatment to obtain a sample, and then carry out a chemical reaction of the sample with polydimethylsiloxane, and then clean and dry it to obtain the gradient anti-fouling coating on the surface of the titanium alloy (denoted as gPDMSCu);

[0049] The oxidation reaction selects micro-arc oxidation method for oxidation reaction. The process of the micro-arc oxidation method is as follows: place the electrolyte in an electrolytic cell, then place the titanium alloy substrate in the electrolyte. The titanium alloy substrate serves as the anode, and 304 stainless steel serves as the cathode. Use a 30KW bipolar pulse micro-arc oxidation power supply to perform micro-arc oxidation treatment. The obtained sample is soaked in deionized water for 40 minutes, and then dried in a vacuum oven; the composition of the electrolyte, by weight, includes 500 parts of sodium silicate, 50 parts of sodium hydroxide, 100 parts of potassium fluoride, 30 parts of a fungicide precursor (copper complex EDTA-Cu), and 320 parts of water.

[0050] The process of the chemical reaction of polydimethylsiloxane is the thermal equilibrium polydimethylsiloxane chemical polymerization reaction method. The process of the thermal equilibrium polydimethylsiloxane chemical polymerization reaction method is as follows: place the sample in a reaction vessel, immerse the sample with linear alkyl-terminated polydimethylsiloxane, react in an oven, the reaction time is 24 hours, and the reaction temperature is 120 °C.

[0051] Comparative Example 1

[0052] A method for preparing a surface coating of a titanium alloy, comprising the following steps:

[0053] (1) Take titanium alloy (TA2), ultrasonically clean it with acetone, ethanol, and deionized water in sequence for 40 minutes, and vacuum dry it;

[0054] (2) Prepare an oxide coating on the titanium alloy substrate by using an oxidation reaction, and then perform a toluene cleaning and activation treatment to obtain a sample. The obtained sample is soaked in deionized water for 40 minutes and then dried in a vacuum oven to obtain a product (denoted as PS).

[0055] The oxidation reaction is carried out by micro-arc oxidation. The process of micro-arc oxidation is as follows: Place the electrolyte in an electrolytic cell, and then place the titanium alloy substrate in the electrolyte. The titanium alloy substrate serves as the anode, and 304 stainless steel serves as the cathode. Use a 30KW bipolar pulse micro-arc oxidation power supply to perform micro-arc oxidation treatment. The obtained sample is soaked in deionized water for 40 minutes and then dried in a vacuum oven. The composition of the electrolyte, by weight, includes 500 parts of sodium silicate, 50 parts of sodium hydroxide, 100 parts of potassium fluoride, 0 part of the fungicide precursor (copper complex EDTA-Cu), and 320 parts of water.

[0056] During the oxidation reaction process, the reaction temperature is controlled by a circulating water-cooled exchanger, and the temperature is controlled below 30°C.

[0057] Comparative Example 2

[0058] A method for preparing a titanium alloy surface coating includes the following steps:

[0059] (1) Take titanium alloy (TA2), and ultrasonically clean it with acetone, ethanol, and deionized water for 40 minutes, and then dry it in a vacuum.

[0060] (2) Prepare an oxide coating on the titanium alloy substrate by using an oxidation reaction, and then perform a toluene cleaning and activation treatment to obtain a sample. The obtained sample is soaked in deionized water for 40 minutes and then dried in a vacuum oven to obtain a product (denoted as PSCu).

[0061] The oxidation reaction is carried out by micro-arc oxidation. The process of micro-arc oxidation is as follows: Place the electrolyte in an electrolytic cell, and then place the titanium alloy substrate in the electrolyte. The titanium alloy substrate serves as the anode, and 304 stainless steel serves as the cathode. Use a 30KW bipolar pulse micro-arc oxidation power supply to perform micro-arc oxidation treatment. The obtained sample is soaked in deionized water for 40 minutes and then dried in a vacuum oven. The composition of the electrolyte, by weight, includes 500 parts of sodium silicate, 50 parts of sodium hydroxide, 100 parts of potassium fluoride, 30 parts of the fungicide precursor (copper complex EDTA-Cu), and 320 parts of water.

[0062] During the oxidation reaction process, the reaction temperature is controlled by a circulating water-cooled exchanger, and the temperature is controlled below 30°C.

[0063] Comparative Example 3

[0064] A method for preparing a titanium alloy surface gradient antifouling coating includes the following steps,

[0065] Take titanium alloy (TA2), ultrasonically clean it successively with acetone, ethanol, and deionized water for 50 minutes, dry it in vacuum, then prepare an oxide coating on the titanium alloy substrate by using an oxidation reaction, and then perform a toluene cleaning and activation treatment to obtain a sample. The sample is then subjected to a chemical reaction with polydimethylsiloxane, and then cleaned and dried to obtain the gradient antifouling coating on the titanium alloy surface (denoted as gPDMS);

[0066] The oxidation reaction is carried out by micro-arc oxidation. The process of micro-arc oxidation is as follows: Place the electrolyte in an electrolytic cell, then place the titanium alloy substrate in the electrolyte. The titanium alloy substrate serves as the anode, and 304 stainless steel serves as the cathode. Use a 30KW bipolar pulse micro-arc oxidation power supply to perform micro-arc oxidation treatment. The obtained sample is soaked in deionized water for 40 minutes, and then dried in a vacuum oven. The composition of the electrolyte, by weight, includes 500 parts of sodium silicate, 50 parts of sodium hydroxide, 100 parts of potassium fluoride, 0 part of a fungicide precursor, and 320 parts of water.

[0067] The process of the chemical reaction with polydimethylsiloxane is the thermal equilibrium polydimethylsiloxane chemical polymerization reaction method. The process of the thermal equilibrium polydimethylsiloxane chemical polymerization reaction method is as follows: Place the sample in a reaction vessel, immerse the sample with linear alkyl-terminated polydimethylsiloxane, and react in an oven. The reaction time is 24 hours, and the reaction temperature is 120 °C.

[0068] Comparative Example 4

[0069] A method for preparing a gradient antifouling coating on a titanium alloy surface includes the following steps.

[0070] Take titanium alloy (TA2), ultrasonically clean it successively with acetone, ethanol, and deionized water for 40 minutes, dry it in vacuum, then prepare an oxide coating on the titanium alloy substrate by using an oxidation reaction, and then perform a toluene cleaning and activation treatment to obtain a sample. The sample is then subjected to a chemical reaction with polydimethylsiloxane, and then cleaned and dried to obtain the gradient antifouling coating on the titanium alloy surface;

[0071] The oxidation reaction is carried out by micro-arc oxidation. The process of micro-arc oxidation is as follows: Place the electrolyte in an electrolytic cell, then place the titanium alloy substrate in the electrolyte. The titanium alloy substrate serves as the anode, and 304 stainless steel serves as the cathode. Use a 30KW bipolar pulse micro-arc oxidation power supply to perform micro-arc oxidation treatment. The obtained sample is soaked in deionized water for 40 minutes, and then dried in a vacuum oven. The composition of the electrolyte, by weight, includes 500 parts of sodium silicate, 50 parts of sodium hydroxide, 100 parts of potassium fluoride, 30 parts of a fungicide precursor (inorganic salt of copper, CuCl2), and 320 parts of water.

[0072] The process of the chemical reaction of polydimethylsiloxane is the thermal equilibrium polydimethylsiloxane chemical polymerization reaction method. The process of the thermal equilibrium polydimethylsiloxane chemical polymerization reaction method is as follows: Place the sample in a reaction vessel, immerse the sample with linear alkyl-terminated polydimethylsiloxane, react in an oven for 24 hours at a reaction temperature of 120 °C.

[0073] For this comparative example sample, the electrolyte could not be stable under the experimental conditions described in this specification and a stable coating could not be formed. Therefore, the anti-fouling experiment results were not measured.

[0074] Comparative Example 5

[0075] A method for preparing a surface gradient anti-fouling coating on a titanium alloy includes the following steps.

[0076] Take titanium alloy (TA2), ultrasonically clean it with acetone, ethanol, and deionized water in sequence for 40 minutes, dry it in vacuum, then prepare an oxide coating on the titanium alloy substrate by using an oxidation reaction, and then perform a toluene cleaning and activation treatment to obtain a sample. The sample is then subjected to a chemical reaction with polydimethylsiloxane, and then cleaned and dried to obtain the surface gradient anti-fouling coating on the titanium alloy.

[0077] The oxidation reaction is carried out by the micro-arc oxidation method. The process of the micro-arc oxidation method is as follows: Place the electrolyte in an electrolytic cell, then place the titanium alloy substrate in the electrolyte. The titanium alloy substrate serves as the anode, and 304 stainless steel serves as the cathode. Use a 30KW bipolar pulse micro-arc oxidation power supply to perform micro-arc oxidation treatment. The obtained sample is soaked in deionized water for 40 minutes and then dried in a vacuum oven. The composition of the electrolyte, by weight, includes 500 parts of sodium silicate, 50 parts of sodium hydroxide, 100 parts of potassium fluoride, 30 parts of a fungicide precursor (copper oxide particles), and 320 parts of water.

[0078] The process of the chemical reaction of polydimethylsiloxane is the thermal equilibrium polydimethylsiloxane chemical polymerization reaction method. The process of the thermal equilibrium polydimethylsiloxane chemical polymerization reaction method is as follows: Place the sample in a reaction vessel, immerse the sample with linear alkyl-terminated polydimethylsiloxane, react in an oven for 24 hours at a reaction temperature of 120 °C.

[0079] For this comparative example sample, the electrolyte was a non-uniform solution under the conditions of this patent and a stable gradient coating containing a fungicide could not be formed. Therefore, the anti-fouling experiment results were the same as those of Comparative Example 3.

[0080] Product effect test

[0081] 1. Anti-marine biofouling experiment: Using Chlorella vulgaris as a representative of fouling organisms, a biofouling attachment experiment was carried out. The products prepared in the examples and comparative examples were hung in Chlorella vulgaris in the ocean for 7 days, and then the surface attachment of Chlorella vulgaris microorganisms was characterized. Observation was carried out using a laser confocal scanning microscope, and the surface attachment rate was statistically analyzed using ImageJ software, so as to calculate the coverage percentage of Chlorella vulgaris on the product surface. The results are as Figure 4 shown.

[0082] 2. Anti-Escherichia coli experiment: After diluting the Escherichia coli strain diluent and immersing the surface gradient antifouling coating samples of the titanium alloy in Example 1 and Comparative Example 3 at 37 °C for 24 hours, 200 microliters of the sample culture solution was taken for each and spread on a plate. Then, after culturing at 37 °C for 12 hours, photographs were taken for observation. The results are as Figure 5 shown. All operations were carried out in a sterile environment, and the experimental consumables used were sterilized by ultraviolet light, alcohol disinfection or burning with an alcohol lamp.

[0083] Figure 1 is the surface morphology diagram of the product prepared in Comparative Example 1; from Figure 1 it can be seen that the surface of the micro-arc oxidation coating without a bactericide presents a typical porous foam structure.

[0084] Figure 2 is the surface morphology diagram of the product prepared in Comparative Example 2; from Figure 2 it can be seen that most of the pores on the surface of the micro-arc oxidation coating show closed pores when adding a Cu bactericide. This kind of closed pore is beneficial to preventing the colonization of bacteria and other microorganisms in it, and improving the anti-biofouling performance of the coating.

[0085] Figure 3 is the infrared spectrum diagram of the surface gradient antifouling coating of the titanium alloy prepared in Example 1; from Figure 3 ( Figure 3 in which "Wavenumber" represents wave number and "Intensity" represents intensity) it can be seen that polydimethylsiloxane polymer molecules were successfully grafted on the surface of the micro-arc oxidation coating, thus forming a gradient antifouling coating.

[0086] Figure 4 is the statistical chart of the surface Chlorella vulgaris attachment amount after a 7-day Chlorella vulgaris attachment experiment on the titanium alloy, the product prepared in Comparative Example 2, and the surface gradient antifouling coating of the titanium alloy prepared in Example 1; from Figure 4 ( Figure 4TA2 in it represents titanium alloy, PSCu represents the product prepared in Comparative Example 2, gPDMSCu represents the surface gradient antifouling coating on the titanium alloy prepared in Example 1, and "Coverage percentage" represents the coverage percentage). It can be seen that the surface gradient antifouling coating on the titanium alloy prepared in Example 1 can effectively reduce the attachment area of Chlorella and has a good effect on preventing marine biofouling.

[0087] Figure 5 It is the anti-Escherichia coli effect diagram of the surface gradient antifouling coating on the titanium alloy prepared in Comparative Example 3 and Example 1. From Figure 5 ( Figure 5 (a) in it corresponds to the anti-Escherichia coli effect of Comparative Example 3, Figure 5 (b) in it corresponds to the anti-Escherichia coli effect of Example 1) It can be seen that the surface gradient antifouling coating on the titanium alloy prepared in Example 1 has a very good anti-Escherichia coli effect, while the anti-Escherichia coli effect of the surface gradient antifouling coating on the titanium alloy prepared in Comparative Example 3 is poor.

Claims

1. A gradient anti-fouling coating on the surface of a titanium alloy, characterized in that, From bottom to top, it successively includes a titanium alloy substrate, an oxide coating, and a brush polymer coating; The oxide coating contains a metal bactericide; The brush polymer coating contains polydimethylsiloxane; The polydimethylsiloxane is a linear alkyl-capped polydimethylsiloxane; The titanium alloy surface gradient antifouling coating is prepared by a preparation method including the following steps: Using an oxidation reaction, an oxide coating is prepared on the titanium alloy substrate, and then activation treatment is carried out to obtain a sample, and the sample is then subjected to a chemical reaction with polydimethylsiloxane to obtain the titanium alloy surface gradient antifouling coating; The activation treatment includes at least one of oxygen plasma treatment and toluene cleaning and activation treatment; The process of the chemical reaction of the polydimethylsiloxane includes: placing the sample in a reaction vessel, immersing the sample with polydimethylsiloxane, reacting in an oven, the reaction time is 10 - 40 hours, and the reaction temperature is 60°C - 180°C.

2. The gradient antifouling coating on the titanium alloy surface according to claim 1, wherein, The metal bactericide is selected from bactericide precursors containing at least one of copper, zinc, strontium, chromium, or tungsten.

3. The gradient antifouling coating on the titanium alloy surface according to claim 2, wherein The bactericide precursor is selected from oxide bactericides containing at least one of copper, zinc, strontium, chromium, or tungsten.

4. The gradient anti-fouling coating on the titanium alloy surface according to claim 1, characterized in that, The oxidation reaction is selected from at least one of micro-arc oxidation method, anodic oxidation method, electrochemical deposition method, and thermal oxidation method for oxidation reaction.

5. The gradient anti-fouling coating on the titanium alloy surface according to claim 4, wherein, The process of the micro-arc oxidation method is: placing the electrolyte in an electrolytic cell, then placing the titanium alloy substrate in the electrolyte, and using a bipolar pulse micro-arc oxidation power supply for micro-arc oxidation treatment; the composition of the electrolyte includes sodium silicate, alkali, potassium fluoride, bactericide precursor, and water; the bactericide precursor is selected from metal complexes or metal salts containing at least one of copper, zinc, strontium, chromium, or tungsten.

6. A device, characterized in that, It includes the titanium alloy surface gradient antifouling coating according to any one of claims 1 - 5.

7. The application of the titanium alloy surface gradient antifouling coating according to any one of claims 1 - 5 in the field of anti-corrosion or anti-fouling.

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