A low surface energy active-passive synergistic antifouling coating and its preparation method

Abstract

This invention discloses a low surface energy active-passive synergistic antifouling coating and its preparation method, belonging to the field of marine antifouling materials technology. The preparation method of the antifouling coating includes the following steps: S1, mixing acetone and xylene and stirring under a nitrogen atmosphere to form a mixed solvent; S2, adding vinyl-terminated silicone resin and acrylic resin to the mixed solvent, stirring and heating to obtain a coating base liquid; S3, adding an initiator to the coating base liquid and continuously stirring and heating to react; S4, after the reaction is complete and the coating base liquid cools, adding functional fillers to form a coating liquid; S5, coating the coating liquid and drying to obtain a low surface energy active-passive synergistic antifouling coating. The low surface energy active-passive synergistic antifouling coating prepared by this invention solves the problem in existing marine antifouling technologies where the single antifouling mechanism prevents the simultaneous consideration of environmental friendliness and long-term effectiveness, and has broad application prospects in the field of marine antifouling materials technology.

Description

Technical Field

[0001] This invention relates to the field of marine antifouling materials technology, specifically to a low surface energy active-passive synergistic antifouling coating and its preparation method. Background Technology

[0002] During the service life of marine engineering equipment such as ships, offshore platforms, and underwater detection equipment, marine biofouling has become a core bottleneck affecting equipment lifespan and reducing operational efficiency. Specifically, marine fouling organisms adhering to the surface of ship hulls significantly increase navigation resistance, leading to a substantial increase in fuel consumption and a surge in operating costs. Biofouling on the structure of offshore platforms and the surface of underwater detection equipment accelerates the corrosion of equipment substrates, shortens maintenance cycles and service life, and also causes problems such as decreased detection accuracy and data distortion, exacerbating operational safety risks. Therefore, the development of efficient, environmentally friendly, and long-lasting marine antifouling coatings has become a key technological requirement urgently needing to be addressed in the field of marine engineering, and is also a core supporting material for ensuring the safe and stable operation of marine engineering equipment.

[0003] Currently, the industry has developed two main types of antifouling coating technologies: antifouling agent release type and fouling desorption type. However, both have insurmountable technical defects due to their single antifouling mechanism, and cannot simultaneously achieve environmental protection and long-term effectiveness. Firstly, although antifouling agent release type coatings can achieve a longer-term antifouling effect through the dissolution of antifouling agents, the antifouling agents (traditionally mostly heavy metal ions such as copper ions) are prone to cumulative pollution in the sea, causing serious damage to the marine ecosystem. Moreover, once the antifouling agent is exhausted, the coating loses its antifouling ability and needs to be frequently recoated to maintain the effect, which greatly increases the operation and maintenance costs. Secondly, although fouling-removing coatings do not require the formulation of antifouling agents and meet environmental protection requirements, their antifouling effect is highly dependent on water flow shear force and lacks the ability to actively remove bacteria, diatoms and other microorganisms that initially attach. They are only suitable for ships with high navigation frequency, stable speed and strict environmental control. In low-speed navigation, long-term berthing (such as offshore platforms) or scenarios without significant water flow shear force, fouling organisms can easily adhere firmly, the antifouling effect drops sharply, and the application scenarios are severely limited (poor static antifouling effect).

[0004] Therefore, the development of a method that can replace traditional toxic antifouling agents, actively remove and inhibit the initial adhesion of microorganisms, and build an environmentally friendly, non-toxic, long-lasting, stable, and multi-scenario adaptable synergistic antifouling system has become a key focus of marine antifouling technology. Summary of the Invention

[0005] To address this issue, the present invention provides a low surface energy active-passive synergistic antifouling coating and its preparation method, thereby solving the problem that existing technologies cannot simultaneously achieve both environmental protection and long-term effectiveness due to the single antifouling mechanism.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] According to a first aspect of the present invention, a method for preparing a low surface energy active-passive synergistic antifouling coating is provided, comprising the following steps:

[0008] S1. Mix acetone and xylene in a mass ratio of 1:(1.2-2) and stir at room temperature under a nitrogen atmosphere to obtain a mixed solvent;

[0009] S2. Add acrylic resin and vinyl-terminated silicone resin to the mixed solvent at a mass ratio of 1:(0.15-0.25), stir and heat until uniformly mixed to obtain the coating base liquid;

[0010] S3. Add the initiator to the coating base liquid at a mass ratio of 1:(80-120) and continue stirring and heating to react;

[0011] S4. After the reaction is complete and cooled, add 0.1-2.5% of the functional filler relative to the total mass of the coating base liquid, sonicate and stir to disperse evenly to obtain the coating liquid;

[0012] S5. Apply the coating liquid to the substrate surface by brushing, spin coating, spraying or scraping, and dry and cure to obtain a low surface energy active and passive synergistic antifouling coating.

[0013] Further, the acrylic resin mentioned in step S2 is a mixture of 2-methoxyethyl acrylate, methyl methacrylate and ethyl acrylate in a mass ratio of 1:(2.5-3.5):(5-7); the vinyl-terminated silicone resin is vinyl-terminated polydimethylsiloxane; the initiator mentioned in step S3 is a mixture of benzoyl peroxide and 2,2'-azobisisobutyronitrile in a mass ratio of 1:(1.5-2.5).

[0014] Furthermore, the functional filler mentioned in step S4 is an antifouling functional active ingredient, and the type of the antifouling functional active ingredient is one or more of the following: catalytic reaction type, organic biological killing type, physical repulsion / fouling release type, colonization inhibition type, hydrophilic anti-adsorption type, or natural biological regulation type.

[0015] Furthermore, the catalytic reaction-type antifouling functional active ingredient includes: nanoenzyme materials, photo / electro / piezoelectric catalytic materials, or composite systems thereof.

[0016] Furthermore, the nanozyme material is a lysine-modified cerium dioxide (Lys@CeO2) nanozyme or a carbon dot-loaded cerium-doped ruthenium dioxide (Ce-RuO2-CDs) nanozyme.

[0017] Furthermore, the preparation method of the lysine-modified cerium dioxide nanozyme includes the following steps:

[0018] S1. Mix L-lysine, cerium source and solvent in a molar-volume ratio of 1 mmol:(1-1.2) mmol:(20-40) mL, stir evenly, moisten and initially complex, and then ultrasonically disperse evenly to obtain a precursor solution. The temperature is maintained at 20-25℃ during the ultrasonic process.

[0019] S2. Stir and heat the precursor solution to react. After the reaction is completed, cool down to terminate the reaction and obtain a reaction solution. Then add 0.05-1.0M sodium hydroxide solution and continue stirring at room temperature to carry out alkali-induced precipitation. The volume ratio of the precursor solution to the sodium hydroxide solution is 1:(0.02-0.4) to obtain Lys@CeO2 nanocolloid dispersion.

[0020] S3. The Lys@CeO2 nanocolloid dispersion is centrifuged at high speed to remove large particle precipitates and obtain a supernatant containing small-sized Lys@CeO2 particles.

[0021] S4. The supernatant containing small-particle Lys@CeO2 is centrifuged and purified using an ultrafiltration centrifuge tube with a molecular weight cutoff of 3-30 kDa to remove solvent and residual reactants. The concentrate from the last ultrafiltration is freeze-dried to obtain lysine-modified cerium dioxide nanozyme.

[0022] Further, the cerium source mentioned in step S1 is cerium ammonium nitrate, cerium nitrate, or cerium chloride; the solvent is N,N-dimethylformamide.

[0023] Furthermore, the preparation method of the carbon dot-loaded cerium-doped ruthenium dioxide nanozyme includes the following steps:

[0024] S1. Spirulina powder and deionized water are mixed at a mass-to-volume ratio of 1g:(15-20)mL and ultrasonically stirred until homogeneous to obtain a uniform dispersion.

[0025] S2. The dispersion is transferred to a hydrothermal reactor, sealed, and placed in an oven at 180-200℃ for hydrothermal reaction. After cooling to room temperature, it is centrifuged at high speed to remove large particle precipitates and the supernatant is collected. The supernatant is dialyzed with a dialysis bag with a molecular weight cutoff of 1-10 kDa and then freeze-dried. After grinding in a mortar, brownish-yellow carbon dot powder is obtained.

[0026] S3. Ruthenium chloride and N,N-dimethylformamide were mixed at a molar-volume ratio of 1 mmol:(20-30) mL, and the mixture was sonicated and stirred to obtain a ruthenium precursor solution.

[0027] S4. Mix cerium ammonium nitrate and N,N-dimethylformamide at a molar-volume ratio of 1 mmol:(20-30) mL, sonicate and stir to obtain a cerium precursor solution;

[0028] S5. Add carbon dot powder and cerium precursor solution to the ruthenium precursor solution, and control the molar ratio of cerium, ruthenium and carbon dot powder to 1 mmol:1 mmol:1.37 g. After ultrasonic stirring, stir and heat in an oil bath at 100-120 °C.

[0029] S6. After the reaction is complete, let the reaction solution cool to room temperature naturally, and slowly add 0.5-5 mL of 0.1-1 M sodium hydroxide solution while stirring. After the addition is complete, continue stirring until complete precipitation to obtain a suspension.

[0030] S7. The suspension is centrifuged at high speed to collect the precipitate, washed with deionized water and then freeze-dried to obtain carbon dot-loaded cerium-doped ruthenium dioxide nanozyme.

[0031] According to a second aspect of the present invention, a low surface energy active-passive synergistic antifouling coating prepared by the above-described preparation method is provided.

[0032] According to a third aspect of the present invention, an application of a low surface energy active-passive synergistic antifouling coating in the preparation of marine antifouling coatings is provided.

[0033] The functional filler in the low surface energy active-passive synergistic antifouling coating provided by this invention is an inorganic or organic material that can impart antifouling properties to the coating. It inhibits the attachment, growth, or colonization of marine fouling organisms through mechanisms such as biokilling, biocolonization inhibition, surface repulsion, or interfacial reactions. The types of fillers include the following six:

[0034] 1. Organic biocidal agents: such as dichlorooctylisothiazolinone (DCOIT) or zinc pyrithione (ZnPT), which inhibit biofilm formation by interfering with microbial cell structure or metabolic processes.

[0035] 2. Colonization-inhibiting type: such as bromopyrrolidone (ECONEA®) or other non-metallic colonization-inhibiting compounds, which achieve the antifouling effect by interfering with the attachment of fouling organism larvae or inhibiting colonization during the development process.

[0036] 3. Physical repulsion / fouling release type: such as organosilicon materials, fluoropolymer materials or fluorosilicone polymer materials, which reduce the intensity of fouling bioattachment by regulating surface energy and interfacial adhesion properties.

[0037] 4. Hydrophilic anti-adsorption type: such as polyethylene glycol derivatives or zwitterionic polymer materials, which inhibit the non-specific adsorption of proteins and microorganisms by constructing a stable hydration layer.

[0038] 5. Catalytic reaction type: such as nanoenzyme materials, photo / electro / piezoelectric catalytic materials and their composite systems, which degrade biofilm components or generate active substances through in-situ catalytic reactions at the interface, thereby achieving active antifouling.

[0039] 6. Natural bioregulatory type: such as cephalosporin-type diterpenoids secreted by corals, natural phenolic compounds and their derivatives, etc., which interfere with fouling bioattachment or physiological processes through natural bioactive components, and usually have lower environmental persistence and bioaccumulation risk.

[0040] The present invention has the following advantages:

[0041] 1. Achieving both environmental friendliness and stability, overcoming the dilemma of using toxic antifouling agents: Using non-toxic Lys@CeO2 or Ce-RuO2-CDs nanozymes instead of traditional antifouling agents eliminates the cumulative pollution of marine ecosystems at its source. L-Lysine introduces hydrophilic functional groups such as amino and carboxyl groups onto the cerium dioxide surface, significantly enhancing the dispersion stability of nanozymes in high-salt marine environments and low surface energy coatings. Furthermore, it improves their anchoring ability in coatings through interfacial hydrogen bonding and ion interactions, effectively inhibiting migration and loss during service. Simultaneously, the Ce in Lys@CeO2... 3+ / Ce 4+ Reversible redox pairs and oxygen vacancies provide continuous and stable active sites for the activation of hydrogen peroxide. Ce-RuO2-CDs nanozymes maintain the highest catalytic activity under seawater pH conditions, overcoming the bottleneck of limited catalytic activity of traditional peroxide nanozymes in marine environments. This provides an efficient catalytic degradation mechanism for environmentally friendly active antifouling coatings, significantly improving the coating's antibacterial, antialgae, and anti-biofouling properties. In this invention, the nanozyme is added at a very low percentage of the total coating mass, yet highly efficient catalytic antifouling is achieved, balancing cost and performance. Both factors ensure that the coating maintains stable catalytic function throughout its service life.

[0042] 2. Static antifouling performance and service life are improved simultaneously, breaking through the bottleneck of scene adaptability of traditional coatings: This invention achieves synergistic effect through the active catalytic function of nanoenzymes and the passive desorption function of low surface energy coatings. Nanoenzymes can actively degrade the initial microbial adhesion layer, inhibiting biofilm formation from the source, thus solving the technical pain point of weak static antifouling capability of traditional single low surface energy coatings. In high-fouling pressure sea areas with high nutrient salts and high microbial density, the antifouling cycle of the coating of this invention is extended to 12-18 months compared with single low surface energy coatings, meeting the long-term service requirements of marine equipment.

[0043] 3. Balancing process versatility and adaptability to multiple scenarios, simplifying application procedures: By optimizing core process parameters such as solvent system and curing temperature, this invention enables the coating to be applied by brushing, spraying, and spin coating, adapting to different application scenarios such as ship hulls, marine exploration equipment, and marine platform structures. Compared to traditional antifouling coatings that require dedicated high-temperature equipment and multiple formulations to adapt to different scenarios, the coating of this invention has a simpler construction process, lower supply chain costs, and reduced overall construction costs. Attached Figure Description

[0044] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0045] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0046] Figure 1 Transmission electron microscopy image of the lysine-modified cerium dioxide nanozyme in Example 1 of the present invention at the 20 nm scale;

[0047] Figure 2 The transmission electron microscope image of the carbon dot-loaded cerium-doped ruthenium dioxide nanozyme in Example 2 of the present invention at the 200 nm scale and the high-resolution magnified image at the 10 nm scale embedded in the upper right corner.

[0048] Figure 3 The energy dispersive X-ray spectrum of the lysine-modified cerium dioxide nanozyme in Example 1 of this invention; wherein Figure 3 a is a dark-field transmission electron microscopy (TEM) image of lysine-modified cerium dioxide nanozyme at the 100 nm scale. Figure 3 b is the cerium element distribution diagram of lysine-modified cerium dioxide nanozyme; Figure 3 c is the nitrogen distribution diagram of the lysine-modified cerium dioxide nanozyme; Figure 3 d is the oxygen distribution diagram of the lysine-modified cerium dioxide nanozyme;

[0049] Figure 4 The energy dispersive X-ray spectroscopy (EDX) spectrum of the cerium-doped ruthenium dioxide nanozyme loaded with carbon dots in Example 2 of this invention; wherein Figure 4 a is a dark-field transmission electron microscopy (TEM) image of cerium-doped ruthenium dioxide nanozymes loaded with carbon dots at the 10 nm scale. Figure 4 b is the carbon element distribution diagram of the cerium-doped ruthenium dioxide nanozyme loaded with carbon dots; Figure 4 c is the ruthenium element distribution diagram of the cerium-doped ruthenium dioxide nanozyme loaded with carbon dots; Figure 4d is the cerium elemental distribution diagram of the cerium-doped ruthenium dioxide nanozyme loaded with carbon dots;

[0050] Figure 5 X-ray diffraction patterns of the lysine-modified cerium dioxide nanozyme and the unmodified cerium dioxide from Example 1 are provided for the present invention.

[0051] Figure 6 X-ray diffraction patterns of carbon dot-loaded cerium-doped ruthenium dioxide nanozyme and undoped carbon dot-loaded ruthenium dioxide nanozyme provided in Example 2 of the present invention;

[0052] Figure 7 Characterization test images of the low surface energy active-passive synergistic antifouling coating based on lysine-modified cerium dioxide nanozyme in Example 1 of this invention. Figure 7 a is the Fourier transform infrared spectrum of the antifouling coating. Figure 7 b is the contact angle test diagram of the antifouling coating. Figure 7 c is the surface energy test chart of the antifouling coating. Figure 7 d is the adhesion test diagram of the antifouling coating;

[0053] Figure 8 Characterization test images of the low surface energy active-passive synergistic antifouling coating based on carbon dot-loaded cerium-doped ruthenium dioxide nanozymes in Example 2 of this invention. Figure 8 a is the Fourier transform infrared spectrum of the antifouling coating. Figure 8 b is the contact angle test diagram of the antifouling coating. Figure 8 c is the surface energy test chart of the antifouling coating. Figure 8 d is the adhesion test diagram of the antifouling coating;

[0054] Figure 9 Schematic diagram of the antibacterial activity of the lysine-modified cerium dioxide nanozyme in different systems provided in Example 1 of the present invention;

[0055] Figure 10 Schematic diagram of the antibacterial properties of carbon dot-loaded cerium-doped ruthenium dioxide nanozyme in different systems in Example 2 of the present invention;

[0056] Figure 11 A schematic diagram of the anti-diatomation effect of the low surface energy active-passive synergistic antifouling coating based on lysine-modified cerium dioxide nanozyme in Example 1 of the present invention on the 7th day after coating on a glass substrate.

[0057] Figure 12 A schematic diagram of the anti-diatomation effect of the low surface energy active-passive synergistic antifouling coating of cerium-doped ruthenium dioxide nanozymes based on carbon dot loading on a glass substrate on the 7th day after coating.

[0058] Figure 13Marine field test image of the low surface energy active-passive synergistic antifouling coating based on lysine-modified cerium dioxide nanozyme in Example 1 of the present invention;

[0059] Figure 14 Marine field test image of the low surface energy active-passive synergistic antifouling coating based on carbon dot-loaded cerium-doped ruthenium dioxide nanozymes in Example 2 of this invention. Detailed Implementation

[0060] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] According to a first aspect of the present invention, a method for preparing a low surface energy active-passive synergistic antifouling coating is provided, comprising the following steps:

[0062] S1. Mix acetone and xylene in a mass ratio of 1:(1.2-2) and stir at room temperature under a nitrogen atmosphere to obtain a mixed solvent;

[0063] S2. Add acrylic resin and vinyl-terminated silicone resin to a mixed solvent at a mass ratio of 1:(0.15-0.25), stir and heat until uniformly mixed to obtain the coating base liquid;

[0064] S3. Add the initiator to the coating base liquid at a mass ratio of 1:(80-120) and continue stirring and heating to react;

[0065] S4. After the reaction is complete and cooled, add 0.1-2.5% of the functional filler relative to the total mass of the coating base liquid, sonicate and stir to disperse evenly to obtain the coating liquid;

[0066] S5. Apply the coating liquid to the substrate surface by brushing, spin coating, spraying or scraping, and dry and cure to obtain a low surface energy active and passive synergistic antifouling coating.

[0067] In step S2, the acrylic resin is a mixture of 2-methoxyethyl acrylate, methyl methacrylate and ethyl acrylate in a mass ratio of 1:(2.5-3.5):(5-7); the vinyl-terminated silicone resin is vinyl-terminated polydimethylsiloxane; and the initiator in step S3 is a mixture of benzoyl peroxide and 2,2'-azobisisobutyronitrile in a mass ratio of 1:(1.5-2.5).

[0068] In step S4, the functional filler is an antifouling functional active ingredient, and the type of antifouling functional active ingredient is one or more of the following: catalytic reaction type, organic biological killing type, physical repulsion / fouling release type, colonization inhibition type, hydrophilic anti-adsorption type, or natural biological regulation type.

[0069] Among them, the catalytic reaction-type antifouling functional active ingredients include: nanoenzyme materials, photo / electro / piezoelectric catalytic materials or their composite systems.

[0070] Among them, the nanozyme material is lysine-modified cerium dioxide (Lys@CeO2) nanozyme or carbon dot-loaded cerium-doped ruthenium dioxide (Ce-RuO2-CDs) nanozyme.

[0071] The preparation method of lysine-modified cerium dioxide nanozyme includes the following steps:

[0072] S1. Mix L-lysine, cerium source and solvent in a molar-volume ratio of 1 mmol:(1-1.2) mmol:(20-40) mL, stir evenly, moisten and initially complex, and then ultrasonically disperse evenly to obtain a precursor solution. The temperature is maintained at 20-25℃ during the ultrasonic process.

[0073] S2. Stir and heat the precursor solution to react. After the reaction is completed, cool down to terminate the reaction and obtain the reaction solution. Then add 0.05-1.0M sodium hydroxide solution and continue stirring at room temperature to carry out alkali-induced precipitation. The volume ratio of precursor solution to sodium hydroxide solution is 1:(0.02-0.4) to obtain Lys@CeO2 nanocolloid dispersion.

[0074] S3. Centrifuge the Lys@CeO2 nanocolloid dispersion at high speed to remove large particle precipitates and obtain a supernatant containing small-sized Lys@CeO2 particles.

[0075] S4. The supernatant containing small-particle Lys@CeO2 was purified by centrifugation using an ultrafiltration centrifuge tube with a molecular weight cutoff of 3-30 kDa to remove solvent and residual reactants. The concentrate from the last ultrafiltration was freeze-dried to obtain lysine-modified cerium dioxide nanozyme.

[0076] In step S1, the cerium source is cerium ammonium nitrate, cerium nitrate, or cerium chloride; the solvent is N,N-dimethylformamide.

[0077] The preparation method of carbon dot-loaded cerium-doped ruthenium dioxide nanozymes includes the following steps:

[0078] S1. Spirulina powder and deionized water are mixed at a mass-to-volume ratio of 1g:(15-20)mL and ultrasonically stirred until homogeneous to obtain a uniform dispersion.

[0079] S2. Transfer the dispersion to a hydrothermal reactor, seal it, and place it in an oven at 180-200℃ for hydrothermal reaction. After cooling to room temperature, centrifuge at high speed to remove large particle precipitates and collect the supernatant. Dialyze the supernatant with a dialysis bag with a molecular weight cutoff of 1-10 kDa, freeze-dry it, and grind it in a mortar to obtain brownish-yellow carbon dot powder.

[0080] S3. Ruthenium chloride and N,N-dimethylformamide were mixed at a molar-volume ratio of 1 mmol:(20-30) mL, and the mixture was sonicated and stirred to obtain a ruthenium precursor solution.

[0081] S4. Mix cerium ammonium nitrate and N,N-dimethylformamide at a molar-volume ratio of 1 mmol:(20-30) mL, sonicate and stir to obtain a cerium precursor solution;

[0082] S5. Add carbon dot powder and cerium precursor solution to the ruthenium precursor solution, and control the molar ratio of cerium, ruthenium and carbon dot powder to 1 mmol:1 mmol:1.37 g. After ultrasonic stirring, stir and heat in an oil bath at 100-120 °C.

[0083] S6. After the reaction is complete, let the reaction solution cool to room temperature naturally, and slowly add 0.5-5 mL of 0.1-1 M sodium hydroxide solution while stirring. After the addition is complete, continue stirring until complete precipitation to obtain a suspension.

[0084] S7. The suspension was centrifuged at high speed to collect the precipitate, washed with deionized water and then freeze-dried to obtain carbon dot-loaded cerium-doped ruthenium dioxide nanozyme.

[0085] According to a second aspect of the present invention, a low surface energy active-passive synergistic antifouling coating prepared by the above-described preparation method is provided.

[0086] To better illustrate the effectiveness of the antifouling coating prepared by this invention, the following embodiments and comparative examples are provided.

[0087] Example 1

[0088] This embodiment provides a method for preparing a low surface energy active-passive synergistic antifouling coating based on lysine-modified cerium dioxide nanozymes. The specific steps are as follows:

[0089] Synthesis of S1, lysine-modified cerium dioxide nanozymes:

[0090] a. Preparation and ultrasonic dispersion of precursor solutions:

[0091] 10 mL of N,N-dimethylformamide was added to a 100 mL round-bottom flask, followed by 50 mg of L-lysine and 0.20 g of cerium ammonium nitrate. The mixture was magnetically stirred at 600 rpm for 10 min to fully wet the solid and initiate complexation. The flask was then placed in an ultrasonic cleaning tank for ultrasonic dispersion. The ultrasonic conditions were set as follows: frequency 40 kHz, power 250 W, and time 15 min. During the ultrasonic process, a circulating water bath was used to control the temperature of the system at 25 °C, resulting in a clear and homogeneous precursor solution.

[0092] b. Stirring and heating the reaction to form a stable solution:

[0093] Place a 10 mL precursor solution in a round-bottom flask in a constant temperature oil bath, maintain a stirring speed of 600 rpm, set the temperature to 80 ℃, and heat the reaction for 2 h. After the reaction is complete, a stable Lys@CeO2 reaction solution is obtained.

[0094] c. Termination of the reaction by ice-water bath and alkali-induced precipitation:

[0095] Immediately after the reaction was completed, the round-bottom flask was placed in an ice-water bath to rapidly cool down and terminate the reaction. The temperature was controlled at 0℃ and maintained for 10 min. After the system cooled and stabilized, 0.2 mL of 0.1 M sodium hydroxide solution was added to 10 mL of the reaction solution. Then, the mixture was brought to room temperature and magnetically stirred at 600 rpm for 30 min to allow the system to undergo alkali-induced precipitation and form a stable Lys@CeO2 nanocolloid dispersion.

[0096] d. Centrifugation to remove large precipitate particles:

[0097] The Lys@CeO2 nanocolloid dispersion was transferred to a centrifuge tube and centrifuged at 10,000 rpm for 10 min. Large particles of precipitate were discarded and the supernatant was retained to obtain a supernatant containing small-sized Lys@CeO2 particles.

[0098] e. Ultrafiltration purification to remove solvent and residual reactants:

[0099] The supernatant was collected and purified by ultrafiltration centrifugation three times using an ultrafiltration centrifuge tube with a molecular weight cutoff of 10 kDa. Each ultrafiltration was performed at 4000 rpm for 15 min, and 10 mL of deionized water was added to the cutoff side after each ultrafiltration before the next round of ultrafiltration to accelerate the removal of N,N-dimethylformamide and residual small molecules / ions. The concentrate obtained from the last ultrafiltration was used as the final product concentrate.

[0100] f. Freeze-drying to obtain the powder product:

[0101] The above final product concentrate was pre-frozen at -80℃ for 30 min, and then freeze-dried in a freeze dryer for 2 days to obtain the target product, lysine-modified cerium dioxide nanozyme.

[0102] S2. Preparation of mixed solvents:

[0103] Add 20g of acetone and 30g of xylene to a 250mL round-bottom flask, purge the air from the flask, and then introduce nitrogen gas to ensure that the reaction system is carried out under nitrogen protection. Then stir at 500rpm for 1h at room temperature and under nitrogen atmosphere to obtain a mixed solvent.

[0104] S3. Preparation of coating base liquid:

[0105] Add 2.5g of 2-methoxyethyl 2-acrylate, 7.5g of methyl methacrylate, 15g of ethyl acrylate and 5g of vinyl-terminated polydimethylsiloxane to the mixed solvent obtained in step S2 in sequence; place the round-bottom flask in an oil bath, stir at 500 rpm and heat at 70°C for 10 min until a homogeneous and transparent liquid is formed to obtain the coating base liquid;

[0106] S4. Copolymerization reaction and coating preparation:

[0107] 0.25 g of benzoyl peroxide and 0.5 g of 2,2'-azobisisobutyronitrile were mixed and added to the coating base solution. The mixture was stirred continuously at 600 rpm and heated at 70°C for 24 h to complete the copolymerization reaction. After the reaction was completed, the mixture was allowed to cool naturally for 8 h. Lys@CeO2 nanozyme (1.0% of the total mass of the coating base solution) was added and sonicated at 40 kHz and 250 W for 30 min, and stirred at 500 rpm for 2 h to ensure uniform dispersion, thus obtaining the coating solution. The coating solution was spin-coated onto a clean glass substrate surface at 2500 rpm for 120 s. The coated substrate was then placed in a 60°C oven and dried and cured for 24 h to obtain a low surface energy active-passive synergistic antifouling coating based on lysine-modified cerium dioxide nanozyme.

[0108] Example 2

[0109] This embodiment provides a method for preparing a low surface energy active-passive synergistic antifouling coating based on carbon dot-loaded cerium-doped ruthenium dioxide nanozymes. The specific steps are as follows:

[0110] S1. Synthesis of cerium-doped ruthenium dioxide nanozymes supported on carbon dots:

[0111] a. Preparation and ultrasonic stirring of carbon source dispersion:

[0112] Add 7g of spirulina powder and 140mL of deionized water to a 250mL beaker, then place the beaker in an ultrasonic cleaning tank for ultrasonic dispersion. The ultrasonic conditions are set as follows: frequency 40kHz, power 250W, and time 30min. After ultrasonication, turn on the magnetic stirrer and set the speed to 500rpm. Stir for 2h to obtain a uniform dispersion.

[0113] b. Preparation of crude carbon dots by hydrothermal reaction:

[0114] The dispersion was transferred to the polytetrafluoroethylene inner liner of the hydrothermal reactor, the inner liner was installed into the matching stainless steel outer reactor body, the reactor lid was tightened and sealed, and the reactor was placed in an oven at 200℃ for 10 hours. After the reaction was completed, the reactor was removed and allowed to cool naturally to room temperature to obtain the carbon point crude reaction solution.

[0115] c. Centrifugation to remove large precipitate particles:

[0116] The crude carbon dot reaction solution was transferred to a centrifuge tube and centrifuged at high speed: the centrifugation conditions were 9000 rpm and 15 min, and the centrifugation was repeated 3 times; after each centrifugation, large particles of precipitate were removed and the supernatant was collected to obtain carbon dot supernatant.

[0117] d. Dialysis to remove small molecule impurities:

[0118] Take the supernatant of carbon dots and transfer it into a dialysis bag with a molecular weight cutoff of 3 kDa. Place it in deionized water for dialysis treatment for 3 days. During this period, change the deionized water every 12 hours to ensure that small molecule impurities are fully removed and obtain the dialyzed carbon dot solution.

[0119] e. Freeze-drying to prepare carbon dot powder:

[0120] The dialyzed carbon dot solution was pre-frozen at -80℃ for 30 minutes, then freeze-dried for 3 days. After the freeze-drying was completed, the product was taken out and ground in a mortar to obtain brownish-yellow carbon dot powder for later use.

[0121] f. Preparation of ruthenium and cerium precursor solutions:

[0122] (1) Preparation of ruthenium precursor solution: Add 10 mL of N,N-dimethylformamide to a 250 mL round bottom flask, then add 0.076 g of ruthenium chloride, and sonicate for 30 min at 40 kHz and 250 W, then stir magnetically at 500 rpm for 60 min to obtain ruthenium precursor solution.

[0123] (2) Preparation of cerium precursor solution: Add 10 mL of N,N-dimethylformamide to a 50 mL beaker, then add 0.2 g of cerium ammonium nitrate, and sonicate for 30 min at 40 kHz and 250 W, then stir magnetically at 500 rpm for 60 min to obtain cerium precursor solution.

[0124] g. Preparation and ultrasonic dispersion of the doped reaction system:

[0125] Add 0.5g of prepared carbon dot powder and cerium precursor solution to the prepared ruthenium precursor solution; first, place the mixture in an ultrasonic cleaning tank for ultrasonic dispersion, and set the ultrasonic conditions as follows: frequency 40kHz, power 250W, time 30min; after ultrasonication, turn on magnetic stirring, set the speed to 400rpm, and stir for 60min to make the system uniformly mixed.

[0126] h. The doping reaction is completed by stirring and heating in an oil bath:

[0127] Place the round-bottom flask in a constant-temperature oil bath, maintain a stirring speed of 400 rpm, set the temperature to 100℃, and heat the reaction for 3 hours.

[0128] i. Alkali-induced precipitation formation:

[0129] After the reaction solution has cooled to room temperature, turn on the magnetic stirrer and set the speed to 450 rpm. Slowly add 0.5 mL of 1 M sodium hydroxide solution. After the addition is complete, keep the speed at 400 rpm and continue stirring for 6 hours to ensure complete precipitation and obtain a suspension.

[0130] j. Centrifuge and wash the precipitate:

[0131] Transfer the suspension to centrifuge tubes and centrifuge at high speed: centrifuge at 10,000 rpm for 10 min, for 3 times; discard the filtrate after each centrifugation, retain the bottom precipitate, and redisperse the precipitate with deionized water before the next round of centrifugation to ensure that residual solvent and impurity ions are fully removed and a clean precipitate is obtained.

[0132] k. Freeze-drying to prepare the target nanoenzyme powder:

[0133] The washed precipitate was pre-frozen at -80℃ for 30 min, and then freeze-dried for 3 days. After freeze-drying, carbon dot-loaded cerium-doped ruthenium dioxide nanozymes were obtained for later use.

[0134] S2. Preparation of mixed solvents:

[0135] Add 20g of acetone and 30g of xylene to a 250mL round-bottom flask, purge the air from the flask, and then introduce nitrogen gas to ensure that the reaction system is carried out under nitrogen protection. Then stir at 500rpm for 1h at room temperature and under nitrogen atmosphere to obtain a mixed solvent.

[0136] S3. Preparation of coating base liquid:

[0137] Add 2.5g of 2-methoxyethyl 2-acrylate, 7.5g of methyl methacrylate, 15g of ethyl acrylate and 5g of vinyl-terminated polydimethylsiloxane to the mixed solvent obtained in step S2 in sequence; place the round-bottom flask in an oil bath, stir at 500 rpm and heat at 70°C for 10 min until a homogeneous and transparent liquid is formed to obtain the coating base liquid;

[0138] S4. Copolymerization reaction and coating preparation:

[0139] 0.25 g of benzoyl peroxide and 0.5 g of 2,2'-azobisisobutyronitrile were mixed and added to the coating base solution. The mixture was stirred continuously at 600 rpm and heated at 70°C for 24 h to complete the copolymerization reaction. After the reaction was completed, the mixture was allowed to cool naturally for 8 h. Ce-RuO2-CDs nanozymes (0.1% of the total mass of the coating base solution) were added and sonicated at 40 kHz and 250 W for 30 min, and stirred at 500 rpm for 2 h to ensure uniform dispersion, thus obtaining the coating solution. The coating solution was spin-coated onto a clean glass substrate surface at 2500 rpm for 120 s. The coated substrate was then placed in a 60°C oven and dried and cured for 24 h to obtain a low surface energy active-passive synergistic antifouling coating based on carbon dot-loaded cerium-doped ruthenium dioxide nanozymes.

[0140] Example 3

[0141] The formula ratio in this embodiment is based on that in Example 1, except that the stirring and heating time in step S3 is 5 minutes. Other operating steps and process parameters are the same as in Example 1.

[0142] Example 4

[0143] The formulation ratio in this embodiment is based on that in Example 1, except that the concentration of sodium hydroxide solution in step S1c is 1.0M. Other operating steps and process parameters are the same as in Example 1.

[0144] Example 5

[0145] The formula ratio in this embodiment is based on that in Example 1, the difference being that in step S1, the stirring speed is 400 rpm, while the other operating steps and process parameters are the same as in Example 1.

[0146] Example 6

[0147] The formulation ratio in this embodiment is based on that in embodiment 1. The difference is that the coating liquid is applied by spraying with a spray gun at a pressure of 0.4 MPa in step S4. Other operating steps and process parameters are the same as in embodiment 1.

[0148] Example 7

[0149] The formulation ratio in this embodiment is based on that in Example 1, the difference being that the reaction temperature in step S1, b is 85°C, while the other operating steps and process parameters are the same as in Example 1.

[0150] Example 8

[0151] The formula ratio in this embodiment is based on that in Example 1. The difference is that the magnetic stirring speed in step S1c is 450 rpm. Other operating steps and process parameters are the same as in Example 1.

[0152] Example 9

[0153] The formula ratio in this embodiment is based on that in embodiment 2, the difference being that in step S1, the stirring speed is 450 rpm, while the other operating steps and process parameters are the same as in embodiment 2.

[0154] Example 10

[0155] The formulation ratio in this embodiment is based on that in embodiment 2. The difference is that in step S1, c, the centrifugation condition is 10,000 rpm. Other operating steps and process parameters are the same as in embodiment 2.

[0156] Example 11

[0157] The formula ratio in this embodiment is based on that in Example 2, the difference being that the pre-freezing condition in step S1, e is -40℃, while the other operating steps and process parameters are the same as in Example 2.

[0158] Example 12

[0159] The formula ratio in this embodiment is based on that in Example 2. The difference is that the stirring speed in steps S1, f, (1) and (2) is 450 rpm. Other operating steps and process parameters are the same as in Example 2.

[0160] Example 13

[0161] The formulation ratio in this embodiment is based on that in embodiment 2, except that in step S1, the ultrasonic power in g is 300W. Other operating steps and process parameters are the same as in embodiment 2.

[0162] Example 14

[0163] The formula ratio in this embodiment is based on that in embodiment 2, except that the stirring speed in step S1 h is 450 rpm. Other operating steps and process parameters are the same as in embodiment 2.

[0164] Comparative Example

[0165] The formulation of this comparative example is based on Example 1, except that step S1 is omitted and Lys@CeO2 nanozyme is not added in step S4. The cooled solution is directly coated, and the other operation steps and process parameters are the same as in Example 1, resulting in a low surface energy antifouling coating without nanozyme.

[0166] Taking into account factors such as cost and time, Examples 1 and 2 are preferred as test subjects, and Test Examples 1-4 and Test Example 7 are completed. Examples 5-6 are completed using Examples 1-14.

[0167] Test Example 1

[0168] The surface morphology of Lys@CeO2 nanozymes in Example 1 and Ce-RuO2-CDs nanozymes in Example 2 was observed by transmission electron microscopy.

[0169] Depend on Figure 1 It can be seen that the particle size of Lys@CeO2 nanozymes is 2.07±0.5nm, indicating that Lys@CeO2 is not only uniform in morphology, but also has a very small particle size; Figure 2 It can be seen that the amorphous Ce-RuO2 nanozyme is dispersed on carbon dots and its size is about 25 nm.

[0170] Test Example 2

[0171] The elemental distribution of Lys@CeO2 nanozymes in Example 1 and Ce-RuO2-CDs nanozymes in Example 2 were characterized by energy dispersive X-ray spectroscopy in this invention.

[0172] Depend on Figure 3 It can be seen that the spatial distribution of Ce, N, and O elements shows significant overlap. Ce originates from CeO2, N from L-lysine, and both CeO2 and lysine contain O. Therefore, the overlap of Ce and N positions indicates that L-lysine was successfully modified onto the surface of CeO2. Figure 4 The distribution of each element can be clearly observed, indicating that Ce is well doped into RuO2 and is evenly dispersed, indicating that Ce-RuO2-CDs were successfully prepared.

[0173] Test Example 3

[0174] The crystal structures of Lys@CeO2 nanozymes in Example 1 and Ce-RuO2-CDs nanozymes in Example 2 were characterized by X-ray diffraction.

[0175] Figure 5 X-ray diffraction patterns of Lys@CeO2 nanozyme and unmodified CeO2 nanozyme provided by the present invention; Figure 6X-ray diffraction patterns of Ce-RuO2-CDs nanozymes and undoped RuO2 provided by this invention.

[0176] The XRD patterns of Lys@CeO2 nanozymes and unmodified CeO2 nanozymes showed high agreement with the standard XRD pattern of pure CeO2 compounds (JCPDS#43-1002), and Lys@CeO2 exhibited almost no impurity peaks, indicating high purity. The strongest diffraction peak at 28.5° corresponds to the (111) crystal plane of CeO2. Following this are peaks at 47.5°, 56.3°, and 33.1°, corresponding to the (220), (311), and (200) crystal planes of CeO2, respectively. The presence of these diffraction peaks confirms the successful preparation of Lys@CeO2 nanozymes.

[0177] The XRD patterns of Ce-RuO2-CDs and RuO2-CDs do not show sharp diffraction peaks, both exhibiting typical amorphous structures. Furthermore, compared to RuO2-CDs, the characteristic peaks of Ce-RuO2-CDs are significantly shifted to lower angles. This is due to the local lattice expansion of RuO2 caused by the doping of Ce ions with larger ionic radii, proving the successful synthesis of Ce-RuO2-CDs nanozymes.

[0178] Test Example 4

[0179] This invention characterizes the low surface energy active-passive synergistic antifouling coating of lysine-modified cerium dioxide nanozyme in Example 1 and the low surface energy active-passive synergistic antifouling coating of carbon dot-loaded cerium dioxide nanozyme in Example 2 using Fourier transform infrared spectroscopy, contact angle meter, and pull-out adhesion tester.

[0180] Figure 7 Characterization test images of the low surface energy active-passive synergistic antifouling coating based on lysine-modified cerium dioxide nanozyme in Example 1 of this invention. Figure 7 a is the Fourier transform infrared spectrum. Figure 7 b is the contact angle test diagram. Figure 7 c is the surface energy test plot. Figure 7 Figure d shows the adhesion test results. The control group is a pure coating without nanozymes, while experimental groups 1-3 are low surface energy active-passive synergistic antifouling coatings with Lys@CeO2 nanozymes added at amounts of 0.1wt%, 0.5wt%, and 1.0wt% (relative to the coating mass fraction), respectively. Figure 7 a shows the FTIR test results of the antifouling coating: 2952 cm⁻¹ -1 The peak observed at 1731 cm corresponds to the stretching vibration of CH; -1 The peak observed at 1455 cm⁻¹ corresponds to the C=O peak of acrylic acid; at 1455 cm⁻¹-1 and 1360cm -1 The peak observed at 1260 cm corresponds to the bending vibration of CH; -1 The peak observed at 1159 cm⁻¹ corresponds to the symmetrical bending vibration of Si-CH₃; at 1159 cm⁻¹ -1 The peak observed at 1021 cm corresponds to the stretching vibration of COC; at 1021 cm -1 and 1090cm -1 The observed peak corresponds to the stretching vibration of linear Si-O-Si; at 796 cm⁻¹ -1 The peak observed at 1650 cm⁻¹ corresponds to the stretching vibration of Si-C; in the figure, 1650 cm⁻¹ -1 No obvious C=C stretching vibration peaks were observed nearby, indicating that there are very few residual carbon-carbon double bonds. FTIR test results show that the coating was successfully synthesized, and the addition of Lys@CeO2 nanozyme as an antifouling agent does not affect the integrity of the coating. Figure 7 b shows the contact angle measurement data of the antifouling coating. It can be seen that the water contact angle is about 110° and the oil contact angle is about 80°. Figure 7 c shows the calculated surface free energies of these antifouling coatings. The control group (pure coating) has the lowest surface energy, at 16.66 mJ·m. -2 As the Lys@CeO2 content increased, the surface energy rose slightly, with the coating with an addition of 1.0 wt% (experimental group 3) exhibiting the highest surface energy, reaching 17.12 mJ·m. -2 . Figure 7 Figure d demonstrates the adhesion strength of the antifouling coating. The low surface energy active-passive synergistic antifouling coating exhibits excellent adhesion performance, with a maximum adhesion strength of up to 4.86 MPa, significantly improving its suitability for marine environments. The addition of Lys@CeO2 has almost no impact on the coating's adhesion strength, and the overall adhesion strength of the coating remains above 4.66 MPa.

[0181] Figure 8 Characterization test images of the low surface energy active-passive synergistic antifouling coating based on carbon dot-loaded cerium-doped ruthenium dioxide nanozymes in Example 2 of this invention. Figure 8 a is the Fourier transform infrared spectrum. Figure 8 b is the contact angle test diagram. Figure 8 c is the surface energy test plot. Figure 8 Figure d shows the adhesion test results. The control group is a pure coating without nanozymes, while experimental groups 1-3 are low surface energy active-passive synergistic antifouling coatings with Ce-RuO2-CDs nanozymes added at amounts of 0.05wt%, 0.1wt%, and 0.2wt% (relative to the coating mass fraction), respectively. Figure 8 a shows the FTIR test results of the composite coating: 2960cm -1The peak observed at 1725 cm corresponds to the stretching vibration of CH; at 1725 cm -1 The peak observed at 1448 cm⁻¹ corresponds to the C=O peak of acrylic acid; at 1448 cm⁻¹ -1 and 1381cm -1 The peak observed at 1259 cm corresponds to the bending vibration of CH; -1 The peak observed at 1157 cm⁻¹ corresponds to the symmetrical bending vibration of Si-CH₃; at 1157 cm⁻¹ -1 The peak observed at 1016 cm corresponds to the stretching vibration of COC; at 1016 cm -1 and 1090cm -1 The observed peak corresponds to the stretching vibration of linear Si-O-Si; at 792 cm⁻¹ -1 The peak observed at 1650 cm⁻¹ corresponds to the stretching vibration of Si-C; in the figure, 1650 cm⁻¹ -1 No obvious C=C stretching vibration peaks were observed nearby, indicating that there are very few residual carbon-carbon double bonds. FTIR test results show that the coating was successfully synthesized, and the addition of Ce-RuO2-CDs nanozymes as an antifouling agent does not affect the integrity of the coating. Figure 8 b shows the contact angle measurement data of the antifouling coating. It can be seen that the water contact angle is about 120° and the oil contact angle is about 80°. Figure 8 c shows the calculated surface free energies of these antifouling coatings. The control group (pure coating) has the lowest surface energy, at 22.97 mJ·m. -2 With the increase of Ce-RuO2-CDs content, the surface energy increased slightly, with the coating with an addition of 0.2 wt% (experimental group 3) exhibiting the highest surface energy, reaching 24.50 mJ·m. -2 . Figure 8 Figure d demonstrates the adhesion strength of the antifouling coating. The low surface energy active-passive synergistic antifouling coating exhibits excellent adhesion performance, with a maximum adhesion strength of up to 4.73 MPa, greatly improving its suitability for marine environments. The addition of Ce-RuO2-CDs has almost no effect on the coating's adhesion strength, and the overall adhesion strength of the coating remains above 4.66 MPa.

[0182] Test Example 5

[0183] Marine biofouling is a multi-stage process, with bacterial attachment to substrate surfaces and biofilm proliferation being key intermediate stages. Therefore, employing nanozymes with catalytic bactericidal capabilities is a promising antifouling strategy, as they can effectively kill bacteria, thereby inhibiting subsequent biofouling. Consequently, antimicrobial testing is an essential component in evaluating the marine antifouling performance of materials.

[0184] The antibacterial rates of the Lys@CeO2 or Ce-RuO2-CDs nanozymes prepared in Examples 1-14 were tested. The antibacterial test used *Escherichia coli* as the target microorganism, and the standard plate count method was used to evaluate the antibacterial performance of the nanozymes. First, a 1×10⁻⁶ concentration of phosphate buffer was prepared. 6 CFU / mL of *E. coli* suspension was prepared. Then, nanozymes and other reaction substrates (bromine ions, hydrogen peroxide) were added to the *E. coli* suspension, and the mixture was incubated with shaking for 3 hours. After incubation, the colony count of the blank group was recorded as U1, and the colony counts of the control and experimental groups were recorded as U2. The antibacterial rate was determined by... Calculate; where U2 is the number of colonies in the experimental group and the control group, U1 is the number of colonies in the blank group, and A is the antibacterial rate of different groups.

[0185] Considering the halogenated peroxidase activity of Lys@CeO2 nanozymes, H2O2 and Br were introduced during the testing process. - The antibacterial experimental results of Lys@CeO2 nanozymes are as follows: Figure 9 As shown, comparative analysis of antibacterial effects indicates that Lys@CeO2 nanozymes and H2O2 / Br - The antibacterial rates of the two groups were 40.8% and 34.1%, respectively. In contrast, Lys@CeO2 / H2O2 / Br - The antibacterial rate of the group was significantly higher, reaching 98.8% (Example 1). This result indicates that the antibacterial rate is significantly higher in the presence of H2O2 and Br. - Under certain conditions, Lys@CeO2 can exert its halogenated peroxidase activity to produce hypobromic acid, thereby killing bacteria.

[0186] Considering the peroxidase activity of Ce-RuO2-CDs nanozymes, H2O2 was introduced during the testing process. The antibacterial experimental results of Ce-RuO2-CDs nanozymes are as follows: Figure 10 As shown, comparative analysis of antibacterial effects revealed that the antibacterial rates of the Ce-RuO2-CDs nanozyme and the H2O2 group were 29.07% and 43.84%, respectively. In contrast, the Ce-RuO2-CDs / H2O2 group exhibited a significantly higher antibacterial rate, reaching 98.01% (Example 2). This result indicates that, in the presence of H2O2, Ce-RuO2-CDs can exert its peroxide-mimicking enzyme activity, generating reactive oxygen species, thereby killing bacteria.

[0187] Using Lys@CeO2 / H2O2 / Br - The antibacterial rate of Lys@CeO2 or Ce-RuO2-CDs nanozymes prepared in Examples 1-14 was tested using a combination of Ce-RuO2-CDs / H2O2. The test results are shown in Table 1.

[0188] Table 1. Antibacterial rates of Lys@CeO2 or Ce-RuO2-CDs nanozymes prepared in Examples 1-14

[0189]

[0190] It can be seen that the nanozymes prepared in Examples 1 to 14 all exhibit good antibacterial activity.

[0191] Test Example 6

[0192] This invention characterizes the antimicrobial adhesion performance of low surface energy active-passive synergistic antifouling coatings through antidiatom testing.

[0193] The diatom resistance test was conducted using a coating. Coated samples and blank samples (glass slides) were immersed in a diatom solution (diatom species: ...). Nitzschia closterium f.minutissima The diatoms were cultured in beakers for 7 days in F / 2 medium at a temperature controlled at 21±2℃. The incubator provided 2000 lux of light with a 12h / 12h light / dark cycle. After the culture period, the sample from the bottom of the beaker was removed, the surface was washed with distilled water, and the diatom adhesion was observed using an optical microscope. The diatom resistance rate of the coating was determined by the formula... Calculate; where N2 is the number of diatoms on the coating surface, N1 is the number of diatoms on the glass slide surface, and r is the diatom resistance rate of the coating.

[0194] The anti-diatomization rates of the low surface energy active-passive synergistic antifouling coatings based on lysine-modified cerium dioxide nanozymes or cerium-doped ruthenium dioxide nanozymes based on carbon dot loading prepared in Examples 1-14, as well as the low surface energy antifouling coatings without nanozymes prepared in the comparative proportions, were tested. The test results are shown in Table 2.

[0195] Table 2. Low surface energy active-passive synergistic antifouling coatings prepared in Examples 1-14 based on lysine-modified cerium dioxide nanozymes or carbon dot-loaded cerium-doped ruthenium dioxide nanozymes, and the anti-diatom rates of low surface energy antifouling coatings without nanozymes prepared in the comparative examples.

[0196]

[0197] It can be seen that the low surface energy active-passive synergistic antifouling coatings based on lysine-modified cerium dioxide nanozymes or cerium-doped ruthenium dioxide nanozymes based on carbon dot loading, prepared in Examples 1-14, as well as the low surface energy antifouling coating without nanozymes prepared in the comparative example, all exhibit good anti-diatom adhesion ability.

[0198] Similar to antibacterial testing, resistance to diatom adhesion is also an important indicator in marine antifouling testing. Low surface energy active-passive synergistic antifouling coatings based on lysine-modified cerium dioxide nanozymes or carbon-doped cerium-doped ruthenium dioxide nanozymes prepared in the examples, and a low surface energy antifouling coating without nanozymes prepared in the comparative example, were immersed in a suspension during the diatom index growth phase and cultured for one week. After the culture period, the diatom adhesion on the sample surface was observed and quantified using an optical microscope. Untreated pure glass slides were used as a blank group, and the comparative example served as a control group.

[0199] Depend on Figure 11 As can be seen, compared with the glass slide (blank group), the number of diatoms adhering to the surface of the antifouling coatings prepared in Example 1 (experimental group) and the comparative example (control group) was significantly reduced. Compared with the comparative example, the antifouling coating prepared in Example 1 had the fewest diatoms on its surface. These results indicate that the inherent low surface energy characteristics of the antifouling coating greatly enhance its anti-diatom performance, and the addition of Lys@CeO2 further improves the antifouling efficiency of the coating. One mechanism to explain this enhancement is that Lys@CeO2 catalyzes the generation of hypobromic acid, inducing intracellular oxidative stress in diatoms, ultimately leading to damage to their cell structure and function and causing cell injury.

[0200] Depend on Figure 12 As can be seen, compared with the glass slide (blank group), the number of diatoms adhering to the surface of the antifouling coatings prepared in Example 2 (experimental group) and the comparative example (control group) was significantly reduced. Compared with the comparative example, the antifouling coating prepared in Example 2 had the fewest diatoms on its surface. These results indicate that the inherent low surface energy characteristics of the antifouling coating greatly enhance its anti-diatom performance, and the addition of Ce-RuO2-CDs further improves the antifouling efficiency of the coating. One mechanistic explanation for this enhancement is that Ce-RuO2-CDs catalyze the generation of reactive oxygen species, thereby leading to oxidative stress and subsequent cell damage within the diatoms.

[0201] Test Example 7

[0202] This invention characterizes the actual antifouling performance of low surface energy active-passive synergistic antifouling coatings through field marine testing.

[0203] The coating was spin-coated onto an epoxy resin plate measuring 50mm × 50mm × 1mm, and after curing, a marine test sample was obtained. The sample was then fixed to a stainless steel chain and immersed in the Bohai Sea. After soaking for a certain period, the sample was removed from the seawater, and the area of ​​dirt accumulation was observed.

[0204] For the low surface energy active-passive synergistic antifouling coating based on lysine-modified cerium dioxide nanozymes, four sets of samples were prepared for comparison: epoxy resin board (blank group), antifouling coating prepared in Example 1 (experimental group), antifouling coating prepared in the comparative example (control group 1), and Jotun coating (commercially available product, control group 2). The test results are as follows: Figure 13 As shown, the dirt coverage area on the sample surface was statistically analyzed using ImageJ software. The blank group had the largest dirt area, with a dirt coverage rate of 89.41%. In contrast, the experimental group had the smallest dirt coverage area, at only 2.97%, while the control group 2 had a dirt coverage area of ​​10.44%, and the control group 1 had a dirt coverage area of ​​41.21%.

[0205] For the low surface energy active-passive synergistic antifouling coating of cerium-doped ruthenium dioxide nanozymes based on carbon dot loading, three sets of samples were prepared for comparison: epoxy resin board (blank group), antifouling coating prepared in Example 2 (experimental group), and antifouling coating prepared in the comparative example (control group 1). The test results are as follows: Figure 14 As shown, the dirt coverage area on the sample surface was statistically analyzed using ImageJ software. The blank group had the largest dirt area, with a dirt coverage rate of 99.87%. In contrast, the experimental group had the smallest dirt coverage area, at only 12.03%, while the control group 1 had a dirt coverage area of ​​78.63%.

[0206] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a low surface energy active-passive synergistic antifouling coating, characterized in that, Includes the following steps: S1. Mix acetone and xylene in a mass ratio of 1:(1.2-2) and stir at room temperature under a nitrogen atmosphere to obtain a mixed solvent; S2. Acrylic resin and vinyl-terminated silicone resin are added to the mixed solvent at a mass ratio of 1:(0.15-0.25), and stirred and heated until uniformly mixed to obtain a coating base liquid. The acrylic resin is a mixed system formed by mixing 2-methoxyethyl acrylate, methyl methacrylate and ethyl acrylate at a mass ratio of 1:(2.5-3.5):(5-7). S3. Add the initiator to the coating base liquid at a mass ratio of 1:(80-120) and continue stirring and heating to react; S4. After the reaction is complete and cooled, add 0.1-2.5% of the functional filler relative to the total mass of the coating base liquid, sonicate and stir to disperse evenly to obtain the coating liquid; The functional filler is an antifouling functional active ingredient; The antifouling functional active ingredient is a nanoenzyme material; The nanozyme material is a lysine-modified cerium dioxide nanozyme or a carbon dot-supported cerium-doped ruthenium dioxide nanozyme. S5. Apply the coating liquid to the substrate surface by brushing, spin coating, spraying or scraping, and dry and cure to obtain a low surface energy active and passive synergistic antifouling coating.

2. The method for preparing the low surface energy active-passive synergistic antifouling coating as described in claim 1, characterized in that, The vinyl-terminated silicone resin mentioned in step S2 is vinyl-terminated polydimethylsiloxane; the initiator mentioned in step S3 is a mixed system formed by mixing benzoyl peroxide and 2,2'-azobisisobutyronitrile in a mass ratio of 1:(1.5-2.5).

3. The method for preparing the low surface energy active-passive synergistic antifouling coating as described in claim 1, characterized in that, The preparation method of the lysine-modified cerium dioxide nanozyme in step S4 includes the following steps: S1. Mix L-lysine, cerium source and solvent in a molar-volume ratio of 1 mmol:(1-1.2) mmol:(20-40) mL, stir evenly, moisten and initially complex, and then ultrasonically disperse evenly to obtain a precursor solution. The temperature is maintained at 20-25℃ during the ultrasonic process. S2. The precursor solution is stirred and heated to react. After the reaction is completed, the temperature is lowered to terminate the reaction, and a reaction solution is obtained. Then, 0.05-1.0M sodium hydroxide solution is added and stirred at room temperature to carry out alkali-induced precipitation. The volume ratio of the reaction solution to the sodium hydroxide solution is 1:(0.02-0.4), and Lys@CeO2 nanocolloid dispersion is obtained. S3. The Lys@CeO2 nanocolloid dispersion is centrifuged at high speed to remove large particle precipitates and obtain a supernatant containing small-sized Lys@CeO2 particles. S4. The supernatant containing small-particle Lys@CeO2 is centrifuged and purified using an ultrafiltration centrifuge tube with a molecular weight cutoff of 3-30 kDa to remove solvent and residual reactants. The concentrate from the last ultrafiltration is freeze-dried to obtain lysine-modified cerium dioxide nanozyme.

4. The method for preparing the low surface energy active-passive synergistic antifouling coating as described in claim 3, characterized in that, The cerium source mentioned in step S1 is cerium ammonium nitrate, cerium nitrate, or cerium chloride; the solvent is N,N-dimethylformamide.

5. The method for preparing the low surface energy active-passive synergistic antifouling coating as described in claim 1, characterized in that, The preparation method of the carbon dot-loaded cerium-doped ruthenium dioxide nanozyme described in step S4 includes the following steps: S1. Spirulina powder and deionized water are mixed at a mass-to-volume ratio of 1g:(15-20)mL and ultrasonically stirred until homogeneous to obtain a uniform dispersion. S2. The dispersion is transferred to a hydrothermal reactor, sealed, and placed in an oven at 180-200℃ for hydrothermal reaction. After cooling to room temperature, it is centrifuged at high speed to remove large particle precipitates and the supernatant is collected. The supernatant is dialyzed with a dialysis bag with a molecular weight cutoff of 1-10 kDa and then freeze-dried. After grinding in a mortar, brownish-yellow carbon dot powder is obtained. S3. Ruthenium chloride and N,N-dimethylformamide were mixed at a molar-volume ratio of 1 mmol:(20-30) mL, and the mixture was sonicated and stirred to obtain a ruthenium precursor solution. S4. Mix cerium ammonium nitrate and N,N-dimethylformamide at a molar-volume ratio of 1 mmol:(20-30) mL, sonicate and stir to obtain a cerium precursor solution; S5. Add carbon dot powder and cerium precursor solution to the ruthenium precursor solution, and control the molar ratio of cerium, ruthenium and carbon dot powder to 1 mmol:1 mmol:1.37 g. After ultrasonic stirring, stir and heat in an oil bath at 100-120 °C. S6. After the reaction is complete, let the reaction solution cool to room temperature naturally, and slowly add 0.5-5 mL of 0.1-1 M sodium hydroxide solution while stirring. After the addition is complete, continue stirring until complete precipitation to obtain a suspension. S7. The suspension is centrifuged at high speed to collect the precipitate, washed with deionized water and then freeze-dried to obtain carbon dot-loaded cerium-doped ruthenium dioxide nanozyme.

6. The low surface energy active-passive synergistic antifouling coating prepared by the preparation method according to any one of claims 1-5.

7. The application of the low surface energy active-passive synergistic antifouling coating according to claim 6 in the preparation of marine antifouling coatings.

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