Antifouling compound, preparation method thereof and marine antifouling paint

Abstract

The invention provides an antifouling compound, a preparation method thereof and a marine antifouling paint, and the preparation method of the antifouling compound comprises the following steps: loading a carboxylic acid natural antifouling agent on aminated porous silicon oxide to obtain an aminated porous silicon oxide antifouling agent; mixing the aminated porous silicon oxide antifouling agent with chitosan in a solution to obtain a mixed solution; and coating the mixed solution on the surface of the substrate covered with the zinc oxide nanorods, and drying to obtain a target product. The antifouling compound obtained by adopting the preparation method shows excellent antibacterial activity and an outstanding antifouling effect, and the antifouling compound also has relatively high safety.

Description

Technical Field

[0001] This invention relates to the fields of coating technology and marine biofouling protection, specifically to an antifouling compound, its preparation method, and a marine antifouling coating. Background Technology

[0002] Ships at sea inevitably become contaminated with bacteria and microorganisms, affecting their normal operation and economic efficiency. In the early stages of biofouling, substances such as proteins and polysaccharides rapidly form a film on the ship's surface. Marine microorganisms (such as bacteria, diatoms, and protozoa) then multiply and proliferate on this film, eventually leading to severe biofouling. This biofouling generates high frictional resistance, increasing fuel consumption and reducing the ship's speed.

[0003] Biofouling can be controlled by coating ship surfaces with substances or materials that inhibit its growth. Applying antimicrobial coatings is currently one of the effective means of preventing biofouling. Generally, this involves using an antimicrobial agent released from the coating to kill bacteria and other microorganisms as they grow on the material's film (i.e., in the early stages of mass marine organism attachment), thus disrupting the environment for subsequent marine organism attachment and preventing biofouling growth. However, conventional antimicrobial coatings often suffer from uneven release rates and short-lived antifouling effects; furthermore, most commercial antifouling paints contain highly toxic bactericides, which, even at low concentrations, can affect fish reproduction and behavior.

[0004] Therefore, developing a safe and highly effective marine antifouling coating remains an unresolved issue. Summary of the Invention

[0005] To address the aforementioned problems, this invention provides an antifouling compound and its preparation method. This antifouling compound exhibits excellent antibacterial activity, outstanding antifouling effect, and high safety. This invention also provides a marine antifouling coating, comprising the aforementioned antifouling coating.

[0006] To achieve the above objectives, the first aspect of the present invention provides a method for preparing an antifouling compound, comprising the following steps:

[0007] A carboxylic acid-based natural antifouling agent was loaded onto aminated porous silica to obtain aminated porous silica@antifouling agent;

[0008] Aminated porous silica@antifouling agent was mixed with chitosan in solution to obtain a mixed solution;

[0009] The aforementioned mixed solution was coated onto the surface of a substrate covered with zinc oxide nanorods, and the target product was obtained after drying.

[0010] Porous silica is a representative of porous materials, and based on its pore size, it can be further divided into microporous silica, mesoporous silica, and macroporous silica. Mesoporous silica, in particular, possesses advantages such as high loading capacity, ease of surface modification, and high mechanical strength and thermal stability, allowing for tight bonding with antifouling agents, thereby reducing release rates and extending the antifouling period. In this invention, common mesoporous silicas, such as MCM-41, SBA-15, and SBA-16 silicon-based mesoporous molecular sieves, or mixtures of various mesoporous silicas can be selected. This invention achieves tight bonding between porous silica, such as mesoporous silica, and carboxylic acid-based natural antifouling agents by amylating the surface of the porous silica, thereby improving the loading capacity and sustained-release performance of the carboxylic acid-based natural antifouling agents.

[0011] In specific implementation, the process of amylating porous silica includes: mixing porous silica with an aminated silane coupling agent in a solvent, reacting at 70–90°C for at least 6 hours, for example, about 12 hours, collecting the solid product and drying it to obtain aminated porous silica. Correspondingly, the method for preparing the antifouling composite provided in this patent also includes the step of amylating porous silica to obtain aminated porous silica.

[0012] The aforementioned aminosilane coupling agent can be, for example, N-(beta-aminoethyl)-gama-aminopropyltrimethoxysilane coupling agent. The amount of the aminosilane coupling agent used can be 30% to 50% of the mass of the porous silica. The aforementioned solvent can be a single organic solvent such as toluene or ethanol, or a mixture of multiple organic solvents.

[0013] After obtaining aminated porous silica, a carboxylic acid-based natural antifouling agent is loaded onto the aminated porous silica to obtain aminated porous silica@antifouling agent. This step can specifically employ commonly used loading processes in the art. One relatively simple and feasible loading process is as follows: the aminated porous silica and the carboxylic acid-based natural antifouling agent are contacted in a solvent, allowing the carboxylic acid-based natural antifouling agent to be loaded onto the aminated porous silica. After loading is complete, the solvent is removed, and the product is washed and dried to obtain aminated porous silica@antifouling agent. Through the above loading process, the carboxylic acid-based natural antifouling agent can electrostatically bond with the amino-modified porous silica.

[0014] In the specific implementation process, the loading process includes: mixing aminated porous silica with solvent, controlling the temperature at 25-35℃ and adding carboxylic acid-based natural antifouling agents while maintaining stirring, mixing for at least 1 hour, generally not less than 5 hours, such as 10 hours.

[0015] The aforementioned carboxylic acid-based natural antifouling agents can specifically be indoleacetic acid (IAA); the solvents used can be low-boiling-point organic solvents such as acetone or ethanol that are readily soluble in water.

[0016] Studies have shown that rationally controlling the mass ratio of aminated porous silica to carboxylic acid-based natural antifouling agents is beneficial to improving the antibacterial properties of antifouling complexes. In practical implementation, the mass ratio of aminated porous silica to carboxylic acid-based natural antifouling agents is generally controlled at 1:(0.5–2), meaning the weight of the carboxylic acid-based natural antifouling agent is 1 / 2 to 2 times the weight of the aminated porous silica. For example, the mass ratios of aminated porous silica to carboxylic acid-based natural antifouling agents are 1:1, 1:2, and 2:1. Furthermore, within the above ratio range, a relatively larger amount of carboxylic acid-based natural antifouling agent is more beneficial to improving the antifouling properties of the antifouling complex. Therefore, the mass ratio of aminated porous silica to carboxylic acid-based natural antifouling agents is generally controlled at 1:(1–2), meaning the weight of the carboxylic acid-based natural antifouling agent is 1 to 2 times the weight of the aminated porous silica.

[0017] After the reaction of aminated porous silica with a carboxylic acid-based natural antifouling agent is completed, the solvent can be removed by means such as rotary evaporation, depending on the specific solvent used. The solid product is then washed multiple times with organic solvents such as acetone, and finally dried at low temperature in a vacuum drying oven to fully remove the organic solvent, yielding aminated porous silica@antifouling agent. For example, if the porous silica used is SBA-15 and the carboxylic acid-based natural antifouling agent is indoleacetic acid, the resulting aminated porous silica@antifouling agent can be denoted as NH2-SBA-15@IAA, which is a reddish-brown powder.

[0018] After obtaining the aminated porous silica@antifouling agent, it can be mixed with chitosan (CS) in solution to obtain a mixed solution. Specifically, chitosan can first be dissolved in an acidic solution to obtain a chitosan solution; then the chitosan solution can be mixed with the aminated porous silica@antifouling agent to obtain a mixed solution.

[0019] Chitosan is a natural, multifunctional biopolymer obtained by partial deacetylation of chitin, and it is the second largest class of polymers after cellulose. Studies have shown that chitosan has significant inhibitory effects on both bacteria and fungi, making it a recognized broad-spectrum antibacterial and bacteriostatic material. Furthermore, chitosan has no toxic side effects, thus possessing the characteristics of safety and environmental friendliness.

[0020] In a specific embodiment of the present invention, chitosan is first dissolved in an acidic aqueous solution, such as in an acetic acid aqueous solution, and then stirred vigorously at 25°C until the chitosan is uniformly dissolved. Then, aminated porous silica@antifouling agent is added to the chitosan solution and mixed thoroughly. The mass fraction of chitosan in the mixed solution can be 0.5%–5%, and the mass fraction of aminated porous silica@antifouling agent in the mixed solution can also be 0.5%–5%. The amounts of chitosan and aminated porous silica@antifouling agent can be the same or different, and the present invention is not particularly limited in this regard.

[0021] Experimental results show that increasing the amount of aminated porous silica@antifouling agent and chitosan can improve the antibacterial effect of the final antifouling complex.

[0022] Metal oxides possess advantages such as broad spectrum, safety, and durability. Combining chitosan with metal oxides to achieve synergistic effects can further enhance antibacterial efficacy. In this invention, the selected metal oxide is zinc oxide (ZnO), more specifically, zinc oxide nanorods. The preparation method of this invention also includes a step of preparing zinc oxide nanorods. These zinc oxide nanorods can be prepared using commonly used nanotechnology processes. In a specific embodiment of this invention, the step of preparing zinc oxide nanorods includes: firstly, forming a zinc oxide seed layer on the surface of a substrate; then placing the substrate with the zinc oxide seed layer in a zinc oxide growth solution to grow zinc oxide nanorods on the zinc oxide seed layer.

[0023] To form a zinc oxide seed layer on the substrate surface, ZnO nanoparticles can be formed first. For example, equimolar amounts of zinc acetate dihydrate (also known as zinc acetate dihydrate) and NaOH are dissolved in ethanol to obtain zinc acetate solution and NaOH solution, respectively. The two solutions are then mixed and continuously stirred in a 60°C water bath to fully react and generate ZnO nanoparticles, resulting in a white turbid liquid. Subsequently, while heated to 65°C, the white turbid liquid containing ZnO nanoparticles is sprayed onto a clean substrate, such as a fiberglass board, thereby forming a zinc oxide seed layer on the substrate surface.

[0024] Equimolar amounts of zinc nitrate hexahydrate and hexamethylenetetramine (also known as hexamethylenetetramine) were dissolved in deionized water to form a precursor solution, namely the zinc oxide growth solution. The glass fiber substrate sprayed with ZnO nanoparticles was then placed in the prepared zinc oxide growth solution and then placed in an oven to grow zinc oxide nanorods on the zinc oxide seed layer. The growth temperature was controlled at 80–95°C. During the growth process, the zinc oxide growth solution was replaced with fresh solution every 2–6 hours, and the total growth time could be controlled to be 20–30 hours. After growth, the glass fiber substrate was removed from the oven, washed with deionized water, and then placed back into the oven to dry, obtaining a substrate coated with a nano-ZnO coating.

[0025] The aforementioned mixed solution is coated onto a substrate covered with a nano-ZnO coating, dried, and then coated two or more times. After drying again, the target product, namely the antifouling composite, is obtained.

[0026] A second aspect of the present invention provides an antifouling compound, which is prepared by the preparation method described in the first aspect above.

[0027] The third invention provides a marine antifouling coating, comprising the antifouling compound provided in the second aspect above.

[0028] In addition to the antifouling compound as the main component, the marine antifouling coating provided by this invention may also contain solvents, pigments, fillers and other components. The specific components and proportions can be selected according to actual needs, which will not be elaborated here.

[0029] The method for preparing the antifouling compound provided by this invention yields an antifouling compound with excellent antifouling properties. Experimental results show that, regardless of whether under light or dark conditions, this antifouling compound exhibits a very significant effect in inhibiting both Gram-positive and Gram-negative bacteria. In particular, by rationally controlling the mass concentrations of chitosan and aminated porous silica@antifouling agent in the mixed solution, the antibacterial activity can be further enhanced. Furthermore, the main components of this antifouling compound are all non-toxic and harmless substances, thus possessing safety and environmental protection characteristics.

[0030] The marine antifouling coating provided by this invention, due to including the above-mentioned antifouling compound, has good antifouling performance and high safety, thereby providing effective protection for marine equipment and facilities. Attached Figure Description

[0031] Figure 1 The antibacterial activity of different coatings against Escherichia coli in Experimental Example 1 of this invention;

[0032] Figure 2 This refers to the antibacterial activity of different coatings against Bacillus subtilis in Experimental Example 2 of this invention. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions and effects of the embodiments and experimental examples of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0034] Example 1

[0035] This embodiment provides a method for preparing an antifouling compound, comprising the following steps:

[0036] Preparation of S1 and NH2-SBA-15: 1 g of SBA-15 and 0.3 g of N-(beta-aminoethyl)-gama-aminopropyltrimethoxysilane coupling agent were added to 70 mL of toluene solvent, heated to about 80 °C and stirred for about 12 hours. The reaction product was collected, filtered, and the solid product was left. After washing three times with toluene, it was placed in a vacuum drying oven and dried at about 70 °C for about 5 hours to obtain a white powder of NH2-SBA-15.

[0037] Preparation of S2 and NH2-SBA-15@IAA: 1 g of NH2-SBA-15 was added to 30 mL of acetone. Indoleacetic acid (IAA) was added and reacted for about 10 hours under heating and stirring at approximately 30 °C. The mass ratio of NH2-SBA-15 to IAA was approximately 1:1.1. After the reaction was complete, the product was rotary evaporated, washed three times with acetone, and then placed in a vacuum drying oven. After drying at approximately 30 °C for 5 hours, a reddish-brown powder NH2-SBA-15@IAA was obtained.

[0038] Preparation of S3 and NH2-SBA-15@IAA@CS: Chitosan CS powder was dissolved in 100 mL of acetic acid aqueous solution and stirred vigorously at 25°C for 24 hours to ensure uniform dissolution of CS, thus obtaining a CS solution; then, NH2-SBA-15@IAA obtained in step S2 was added to the CS solution to obtain a mixed solution of NH2-SBA-15@IAA and CS; wherein the volume of acetic acid in the acetic acid aqueous solution was 1% of the total volume of the acetic acid aqueous solution; the mass fraction of CS and NH2-SBA-15@IAA in the mixed solution was approximately 0.5%.

[0039] Synthesis of S4, ZnO nanoparticles and seed crystals: 4 mmol of zinc acetate dihydrate and 4 mmol of NaOH were dissolved separately in 100 mL of ethanol with continuous stirring. The two solutions were then mixed and continuously stirred in a water bath at 60 °C for 2 hours to obtain a white turbid solution. Finally, the ZnO nanoparticle solution was sprayed onto a clean glass fiber plate while heated to 65 °C.

[0040] S5. Growth of ZnO nanorods: 10 mmol of zinc nitrate hexahydrate and 10 mmol of hexamethylenetetramine (HXMT) were dissolved in 1.5 L of deionized water to form a clear and transparent precursor solution. The ZnO-coated glass fiber plate was placed in the prepared precursor solution and then placed in a 90°C oven for 5 hours. Afterward, the precursor solution was replaced, and the plate was placed back into the 90°C oven. The fresh precursor solution was replaced approximately every 5 hours, for a total growth time of 25 hours. After the required growth time, the sample was washed with deionized water and dried in a 90°C oven to obtain a glass fiber plate coated with a layer of ZnO nanorods.

[0041] Preparation of S6 and NH2-SBA-15@IAA@CS / ZnO: The glass fiber board dried in step S5 is taken out of the oven and coated with the NH2-SBA-15@IAA@CS solution prepared in step S3. Then it is dried at 25°C overnight. The NH2-SBA-15@IAA@CS solution is coated twice and dried to obtain a glass fiber board with an antifouling composite coating on the surface.

[0042] Example 2-3

[0043] Examples 2 and 3 each provide a method for preparing an antifouling complex, which is basically the same as the preparation method in Example 1, except for the amount of chitosan CS and NH2-SBA-15@IAA used in step S3. Specifically, in Example 2, the mass fractions of CS and NH2-SBA-15@IAA in the mixed solution are approximately 1.0%; in Example 3, the mass fractions of CS and NH2-SBA-15@IAA in the mixed solution are approximately 2.0%.

[0044] Experimental Example 1

[0045] The antifouling activity of the antifouling complex (hereinafter referred to as CS / ZnO) prepared in Examples 1-3 against Gram-negative bacteria (Escherichia coli) was tested under both light and dark conditions. Uncoated pure glass fiber boards and chitosan CS-coated and ZnO-coated boards were used as controls. The experimental procedure is as follows:

[0046] The antibacterial properties of the samples were tested using the plate coating method. The test steps were as follows: (1) Material preparation: Prepare LB liquid culture medium and sterilize it at 120°C for 15 min in a high-temperature and high-pressure steam sterilizer. Sterilize the prepared LB solid culture medium using the above method and pour it into a sterile petri dish for later use. Select a single colony of Escherichia coli and activate it for later use. Place the test samples into disposable petri dishes according to the group and sterilize them under ultraviolet light on both sides for 30 min each. (2) Plate coating and counting: Dilute the bacterial solution to about 10 CFU / mL with sterile PBS solution. Place the sample into a 24-well plate and add 2 mL of diluted bacterial solution to each sample well. Add an equal amount of bacterial solution to an empty well as a blank control. Incubate in a constant temperature incubator at 37°C for 24 h. After the culture is completed, dilute the bacterial solution 10 times with sterile PBS solution. Take 100 μL of the diluted solution and spread it evenly on the LB solid culture medium. Incubate in a constant temperature incubator at 37°C for 18 h and record the colony count. (3) Antibacterial rate statistics: The colony count is the colony count result of each group at the corresponding dilution factor. The counting principle is based on the national standard GB 4789.2—2022 "National Food Safety Standard Microbiological Examination of Food - Determination of Total Colony Count", and the colony count is selected between 30 CFU and 300 CFU. The bacterial concentration (CFU / mL) is calculated as: colony count × dilution factor × 10 (0.1 mL spread).

[0047] Figure 1 a and Figure 1 In b, Control represents an uncoated pure glass fiber board; ZnO represents a glass fiber board coated with a nano ZnO coating obtained by simply using the method in step S5 of Example 1; 0.5%CS, 1%CS, and 2%CS represent coatings formed by preparing a mixed solution according to steps S1 to S3 of Examples 1 to 3 and directly applying the mixed solution to a pure glass fiber board, i.e., 0.5%CS, 1%CS, and 2%CS represent the mass fraction of CS in the mixed solution as 0.5%, 1%, and 2%, respectively; 0.5%CS / ZnO, 1%CS / ZnO, and 2%CS / ZnO represent glass fiber boards with an antifouling composite coating obtained in steps S1 to S6 of Examples 1 to 3, respectively.

[0048] like Figure 1As shown in Figure a, after 24 hours of illumination, the uncoated pure fiberglass board (Control group) exhibited the highest colony density. All CS coatings and CS / ZnO coatings showed significant inhibitory effects on *E. coli*, demonstrating a significant difference compared to the Control group. Among the three CS coating groups, the 2% CS coating showed the lowest *E. coli* density, indicating a more pronounced inhibitory effect and the best antifouling performance. Similarly, among the three CS / ZnO coating groups, the 2% CS / ZnO coating also showed the lowest *E. coli* density, indicating a more pronounced inhibitory effect and the best antifouling performance. Further comparison of the 2% CS and 2% CS / ZnO coatings revealed that the latter exhibited a stronger antibacterial effect against *E. coli*.

[0049] like Figure 1 As shown in b, even under dark conditions, both the CS coating and the CS / ZnO coating exhibited significant antifouling activity after 24 hours, maintaining a trend consistent with those under light conditions. The 2% CS / ZnO coating showed the lowest E. coli density in the dark environment, demonstrating that it not only produces an antibacterial effect under light stimulation but also effectively inhibits E. coli even in the absence of light. In contrast, the Control group (uncoated pure fiberglass board) also exhibited a higher colony density under dark conditions, further confirming the excellent antibacterial performance of the CS / ZnO coating.

[0050] Experimental Example 2

[0051] This experimental example also uses the plate coating method to test the antibacterial properties of the sample. The testing process is basically similar to that of Experiment 1, except that Escherichia coli is replaced with Bacillus subtilis.

[0052] like Figure 2 As shown in Figure a, after 24 hours of cultivation under light conditions, the highest density of Bacillus subtilis was detected on the Control group (uncoated pure glass fiber board). Compared with the Control group, 2% CS / ZnO, 1% CS / ZnO, 0.5% CS / ZnO, and ZnO nanorod coatings all significantly reduced the number of Bacillus subtilis. The CS coating can also reduce bacterial density to some extent, but its antifouling effect is significantly weaker than that of the CS / ZnO coating. This indicates that the CS / ZnO coating exhibits strong inhibitory activity against Bacillus subtilis under light conditions and can significantly reduce the number of colonies within 24 hours. This suggests that the synergistic effect between CS and ZnO nanoparticles makes CS / ZnO more advantageous in terms of antibacterial and anti-adhesion properties.

[0053] like Figure 2As shown in b, under dark conditions, various coatings still exhibit some inhibitory effect on Bacillus subtilis, but their effectiveness is generally lower than under light conditions. In particular, the 2% CS / ZnO coating shows an antibacterial effect approximately 4.5 times that in the dark environment under light. The ZnO nanorod coating also exhibits strong antifouling properties under light, but its effectiveness is significantly reduced in the dark.

[0054] It should be noted that because *E. coli* is relatively weak, its colony concentration after 24 hours is usually lower than the initial concentration at 0 hours when antimicrobial agents are present. *Bacillus subtilis*, however, is far more resilient than *E. coli*. Therefore, even in the presence of antimicrobial agents, the concentration of *Bacillus subtilis* (CFU) after 24 hours will still be significantly higher than the initial concentration at 0 hours, leading to… Figure 1 and Figure 2 The trends are different. However, through horizontal comparison, it can still be determined that the antifouling compound prepared in the embodiments of the present invention has significantly better antibacterial properties than the control group.

[0055] In summary, this invention successfully developed an antifouling compound with excellent antifouling properties that is safe and environmentally friendly, exhibiting significant effects in inhibiting both Gram-positive and Gram-negative bacteria. Experimental results show that the 2% CS / ZnO coating demonstrates excellent antibacterial activity under both light and dark conditions, with the antifouling effect under light conditions being particularly outstanding.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the technical solutions of the present invention have been described in detail with reference to the foregoing embodiments and experimental examples, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the present invention.

Claims

1. A method for preparing an antifouling compound, characterized by, The method comprises the following steps: loading a carboxylic acid natural antifouling agent on the aminated porous silica to obtain an aminated porous silica@antifouling agent; mixing the aminated porous silica@antifouling agent and chitosan in a solution to obtain a mixed solution; applying the mixed solution on a substrate surface covered with zinc oxide nanorods, and drying to obtain a target product.

2. The production method according to claim 1, characterized by, The porous silica is mesoporous silica.

3. The production method according to claim 1 or 2, characterized by, The method further comprises the step of aminating the porous silica: mixing the porous silica and an aminated silane coupling agent in a solvent, and reacting at 70-90 ℃ for at least 6 hours, collecting the solid product and drying to obtain the aminated porous silica; wherein the aminated silane coupling agent accounts for 30%-50% of the mass of the porous silica.

4. The method of claim 1, wherein, The carboxylic acid natural antifouling agent is indole acetic acid.

5. The production method according to claim 1 or 4, characterized by, The process for obtaining the aminated porous silica@antifouling agent comprises: contacting the aminated porous silica and the carboxylic acid natural antifouling agent in a solvent to load the carboxylic acid natural antifouling agent on the aminated porous silica, wherein the mass ratio of the aminated porous silica to the carboxylic acid natural antifouling agent is 1:(0.5-2), the temperature during the contacting is 25-35 ℃, and the contacting time is not less than 1 hour; after the loading is completed, removing the solvent and washing and drying the product to obtain the aminated porous silica@antifouling agent.

6. The method of claim 1, wherein, The process for obtaining the mixed solution comprises: dissolving chitosan in an acidic solution to obtain a chitosan solution; mixing the chitosan solution and the aminated porous silica@antifouling agent to obtain the mixed solution, wherein the mass fraction of chitosan in the mixed solution is 0.5%-5%, and the mass fraction of the aminated porous silica@antifouling agent in the mixed solution is 0.5%-5%.

7. The preparation method according to claim 1, characterized in that, The method further comprises the step of preparing the zinc oxide nanorods: forming a zinc oxide seed layer on a substrate surface; placing the substrate in a zinc oxide growth solution to grow the zinc oxide nanorods on the zinc oxide seed layer, wherein the growth temperature is controlled to be 80-95 ℃.

8. The preparation method according to claim 7, characterized in that, During the growth of the zinc oxide nanorods, the fresh zinc oxide growth solution is replaced every 2-6 hours, and the total growth time is 20-30 hours.

9. An antifouling compound, characterized in that, The method is prepared by the method of any one of claims 1-8.

10. A marine antifouling coating, characterized by, The method comprises the antifouling composite of claim 9.

Images