A method for catalytically preparing super-hydrophobic nanocellulose-based antifouling material by laccase

Abstract

The present application relates to a kind of laccase catalytic preparation super-hydrophobic nanocellulose-based antifouling material method, comprising the following steps: S1, gelidium nanocellulose is placed in water ultrasonic dissolution, join laccase and dopamine, adjust pH value to 5.5, water bath heating, obtain polydopamine modified gelidium nanocellulose;S2, octadecylamine is placed in anhydrous ethanol ultrasonic dissolution, join water and polydopamine modified gelidium nanocellulose, normal temperature reaction polymerization, obtain super-hydrophobic nanocellulose-based material, join EGCG and mix, obtain super-hydrophobic nanocellulose-based antifouling material.The laccase catalysis two-step method of the present application, laccase catalysis can be carried out efficiently under neutral conditions, catalytic reaction is mild, the polydopamine generated is more uniform, and avoid strong alkali damage cellulose structure;Meanwhile, dopamine polymerization and octadecylamine hydrophobic modification are carried out in steps, promote molecular ordered arrangement, also make chemical bonding more stable, improve coating structure, overcome the problem of "one-pot method" coating crystallinity low, poor thermal stability.

Description

Technical Field

[0001] This invention relates to the field of antifouling materials technology, and in particular to a method for preparing superhydrophobic nanocellulose-based antifouling materials by laccase catalysis. Background Technology

[0002] Marine biofouling (such as the attachment of microorganisms, algae, and shellfish) can have serious negative impacts on ships and marine facilities, increasing fuel consumption and potentially causing ecological pollution. Traditional antifouling materials, such as organotin and copper-based compounds, are restricted due to their high ecotoxicity. In recent years, bio-based antifouling materials (utilizing natural extracts such as capsaicin and chitosan) have become a research hotspot, but they generally face problems such as high water solubility, easy loss, and poor long-term effectiveness.

[0003] Gracilaria processing waste (gracilaria residue) is rich in nanocellulose, and its surface hydroxyl groups are highly modifiable, offering advantages in both coating adhesion and specific surface area. Chinese patent CN119432169A discloses a method for preparing agracilaria nanocellulose-based antifouling coating, employing a "one-pot method" to simultaneously react gecko nanocellulose, octadecylamine, and dopamine hydrochloride, followed by the introduction of EGCG. While the coating prepared by this method exhibits good self-cleaning properties, chemical stability, and antifouling effects, its application is limited due to molecular disorder caused by the simultaneous reaction and the constraints of reaction conditions (traditional dopamine polymerization requires alkaline conditions (pH=8-9), resulting in slow reaction rates, uneven coatings, and potential damage to the cellulose structure). This leads to defects such as low crystallinity and insufficient thermal stability.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for preparing superhydrophobic nanocellulose-based antifouling materials using laccase catalysis.

[0006] The technical solution adopted in this invention is as follows: This invention provides a method for preparing superhydrophobic nanocellulose-based antifouling materials using laccase catalysis, comprising the following steps: S1. Dissolve the agar nanocellulose in water by ultrasonication, add laccase and dopamine, adjust the pH to 5.5, and heat in a water bath to obtain polydopamine-modified agar nanocellulose. S2. Dissolve octadecylamine in anhydrous ethanol by ultrasonication, add water and the polydopamine-modified agar nanocellulose, and polymerize at room temperature to obtain a superhydrophobic nanocellulose-based material. Add EGCG and mix to obtain a superhydrophobic nanocellulose-based antifouling material.

[0007] This invention proposes a laccase-catalyzed method for preparing superhydrophobic nanocellulose-based antifouling materials. Using agar-agar nanocellulose as a substrate, laccase efficiently catalyzes the oxidation of dopamine under neutral conditions to generate a quinone structure, constructing a uniform and dense polydopamine strong adhesion layer on the cellulose surface. This layer then undergoes a Michael addition reaction with octadecylamine to form a covalently bonded, ordered hydrophobic layer. Finally, the natural antifouling agent EGCG is stably loaded, enhancing the antibacterial and antifouling properties of the coating. This invention's two-step laccase-catalyzed method allows for efficient laccase catalysis under neutral conditions, resulting in a mild catalytic reaction and more uniform polydopamine formation, while avoiding damage to the cellulose structure from strong alkalis. Simultaneously, the oxidative polymerization of dopamine and the hydrophobic modification of octadecylamine occur stepwise, promoting ordered molecular arrangement and stabilizing the chemical bonds between the two, thereby improving the coating structure and overcoming the problems of low crystallinity and poor thermal stability inherent in existing one-pot methods for coating preparation. This invention provides an effective method for the reuse of agar-agar waste. The reaction conditions are mild and the production efficiency is high. The coating formed by the superhydrophobic nanocellulose-based antifouling material prepared by this invention has superhydrophobic, long-lasting antifouling and antibacterial properties, which contributes to the sustainable development of the marine antifouling field.

[0008] Preferably, in step S1, the amount of laccase added is 0.05-0.25 U / mL; and the water bath heating time is 0.5-2.5 h. In step S2, the mass ratio of agar nanocellulose to octadecylamine is 1:2-6; the polymerization time at room temperature is 2-6 hours.

[0009] More preferably, a single-factor experiment was conducted, using the contact angle of the superhydrophobic nanocellulose-based material as an indicator, to screen the optimal amount of laccase, water bath heating time, mass ratio of agar nanocellulose to octadecylamine, and room temperature reaction polymerization time.

[0010] More preferably, the optimal process conditions are: the amount of laccase added is 0.1 U / mL, the water bath heating time is 1 h, the mass ratio of agar nanocellulose to octadecylamine is 1:4, and the room temperature reaction polymerization time is 5 h.

[0011] Preferably, in step S1, the mass ratio of the agar nanocellulose to the dopamine is 1:1.5-2.5.

[0012] Preferably, in step S1, the water bath heating temperature is 45-50℃.

[0013] Preferably, in step S2, the amount of EGCG added is 2-4 wt% of the mass of the superhydrophobic nanocellulose-based material.

[0014] Preferably, in step S1 and / or step S2, the conditions for ultrasonic dissolution are: ultrasonic power of 300-400W, ultrasonic frequency of 25-30KHz, ultrasonic temperature of 25-35℃, and ultrasonic time of 20-40min. Attached Figure Description

[0015] Figure 1 The effect of different process parameters on the contact angle of the superhydrophobic nanocellulose-based material in Example 1 is shown. A is the amount of laccase added, B is the water bath heating time (laccase catalysis time), C is the mass ratio of agar nanocellulose (TOCN) to octadecylamine (ODA), and D is the room temperature reaction polymerization time (reaction time of polydopamine and octadecylamine). Different letters indicate significant differences (p<0.05). Figure 2 Fourier transform infrared spectroscopy characterization results for different coatings; Figure 3 X-ray diffraction analysis results for different coatings; Figure 4 Thermogravimetric analysis results for different coatings; Figure 5 This diagram illustrates the self-cleaning process of sand and chalk dust with different coatings. A represents IOPTE, and B represents IOPT. Figure 6 The chemical stability test results for different coatings are shown in Figure A. Salt ion concentration test: a is immersion in 1.5wt% NaCl solution, b is immersion in 3.5wt% NaCl solution, and c is immersion in 5.5wt% NaCl solution. The acid and alkali resistance test is shown in Figure B. Strong acid immersion, e is neutral immersion, and f is strong alkali immersion. Figure 7 The results show the universality test results for different coating substrates. A is the substrate coated with IOPT, and B is the substrate coated with IOPTE. Figure 8 The adhesion morphology of different coatings and contaminants is shown in Figure A, which is the morphology of the blank iron sheet, Figure B is the morphology of the IOPT coating, and Figure C is the morphology of the IOPTE coating. Detailed Implementation

[0016] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0017] This embodiment provides a method for preparing superhydrophobic nanocellulose-based antifouling materials using laccase catalysis, comprising the following steps: S1. Dissolve the agar nanocellulose in water by ultrasonication, add laccase and dopamine, adjust the pH to 5.5, and heat in a water bath to obtain polydopamine-modified agar nanocellulose. S2. Dissolve octadecylamine in anhydrous ethanol by ultrasonication, add water and polydopamine-modified agar nanocellulose, and polymerize at room temperature to obtain a superhydrophobic nanocellulose-based material. Add EGCG and mix to obtain a superhydrophobic nanocellulose-based antifouling material.

[0018] Through research, the inventors discovered that the "one-pot method" in patent CN119432169A suffers from molecular disorder, limited reaction conditions, and insufficient chemical bonding due to simultaneous reactions, which are the core reasons for the low crystallinity and poor thermal stability of its coating. The inventors innovatively employ a two-step laccase-catalyzed method, utilizing laccase to catalyze the efficient polymerization of dopamine under neutral conditions and separating the steps of dopamine self-polymerization and octadecylamine grafting, thereby improving the coating structure and overcoming the drawbacks of the existing "one-pot method." If only laccase is introduced for catalysis on the basis of the "one-pot method" (i.e., directly reacting agar nanocellulose, laccase, dopamine, and octadecylamine), or if only the dopamine polymerization and octadecylamine modification of the "one-pot method" are carried out stepwise, the former will result in problems such as uneven coverage of polydopamine layer, random distribution of octadecylamine hydrophobic chains, and damage to cellulose crystal structure due to the competitive reaction between dopamine self-polymerization and cross-linking of octadecylamine in the reaction system, which inhibits laccase activity and results in disordered cross-linking, and the latter will result in problems such as slow dopamine self-polymerization and partial decomposition of cellulose under alkaline conditions. As a result, the crystallinity of the coating will decrease and the thermal decomposition rate will accelerate.

[0019] Additionally, it should be noted that the preparation of agar-agar nanocellulose in this embodiment adopts the method of low eutectic solvent extraction and cellulase enzymatic hydrolysis combined with TEMPO oxidation under optimal process conditions, as described in patent CN119432169A. Specifically, a choline chloride-lactic acid low eutectic solvent (mixed at a molar ratio of 1:2 under anhydrous conditions and heated at 60°C for 2 hours) was mixed with agar-agar residue at a mass ratio of 20:1 and then heated in an oil bath at 100°C for 3 hours. After the reaction, the supernatant was removed by centrifugation, and the mixture was washed and dried to obtain agar-agar cellulose. The agar-agar cellulose was then subjected to cellulase enzymatic hydrolysis (enzyme-to-base ratio of 10% w / w, hydrolysis pH of 4.8, hydrolysis temperature of 60°C, and hydrolysis time of 3 hours) and TEMPO oxidation (sodium hypochlorite specific volume of 11 mL / g, oxidation system pH of 10.5, and oxidation reaction time of 24 hours) to obtain agar-agar nanocellulose.

[0020] In a preferred embodiment, in step S1, the amount of laccase added is 0.05-0.25 U / mL; the water bath heating time is 0.5-2.5 h; In step S2, the mass ratio of agar nanocellulose to octadecylamine is 1:2-6; the polymerization time at room temperature is 2-6 hours.

[0021] In a more preferred embodiment, a single-factor experiment is used to screen the optimal amount of laccase, water bath heating time, mass ratio of agar nanocellulose to octadecylamine, and room temperature reaction polymerization time, using the contact angle of the superhydrophobic nanocellulose-based material as an indicator.

[0022] In a more preferred embodiment, the optimal process conditions are: laccase addition of 0.1 U / mL, water bath heating time of 1 h, mass ratio of agar nanocellulose to octadecylamine of 1:4, and room temperature polymerization time of 5 h.

[0023] In a preferred embodiment, in step S1, the mass ratio of agar nanocellulose to dopamine is 1:1.5-2.5.

[0024] In a preferred embodiment, in step S1, the water bath heating temperature is 45-50°C.

[0025] In a preferred embodiment, in step S2, the amount of EGCG added is 2-4 wt% of the mass of the superhydrophobic nanocellulose-based material.

[0026] In a preferred embodiment, the conditions for ultrasonic dissolution in step S1 and / or step S2 are: ultrasonic power of 300-400W, ultrasonic frequency of 25-30KHz, ultrasonic temperature of 25-35℃, and ultrasonic time of 20-40min.

[0027] Example 1 A method for preparing superhydrophobic nanocellulose-based antifouling materials by laccase catalysis includes the following steps: S1. Dissolve 0.2g of agar-agar nanocellulose in 50mL of water by ultrasonication (ultrasonication conditions: ultrasonic power 350W, ultrasonic frequency 28KHz, ultrasonic temperature 30℃, ultrasonic time 30min). Add 0.05-0.25U / mL laccase and 0.4g dopamine, adjust the pH to 5.5, heat in a water bath at 50℃ for 0.5-2.5h, centrifuge, wash, collect the precipitate, and obtain polydopamine-modified agar-agar nanocellulose.

[0028] S2. According to the above-mentioned mass ratio of agar-agar nanocellulose (raw material) to octadecylamine is 1:2-6, octadecylamine is placed in 50mL of anhydrous ethanol and ultrasonically dissolved (the ultrasonic dissolution conditions are the same as in step S1). 50mL of water and the above-mentioned polydopamine-modified agar-agar nanocellulose are added, and the reaction is carried out at room temperature (25℃) for 2-6h to obtain a superhydrophobic nanocellulose-based material. EGCG is added and mixed (the amount of EGCG added is 2wt% of the mass of the superhydrophobic nanocellulose-based material) to obtain a superhydrophobic nanocellulose-based antifouling material.

[0029] Single-factor experiments were conducted, using the contact angle of the superhydrophobic nanocellulose-based material as an indicator, to screen the optimal amount of laccase, water bath heating time, mass ratio of agar nanocellulose to octadecylamine, and room temperature polymerization time.

[0030] Specifically, (1) the screening steps for the amount of laccase added included: under the conditions of a fixed water bath heating time (laccase catalysis time) of 1 h, a mass ratio of agar nanocellulose to octadecylamine of 1:4, and a room temperature reaction polymerization time (reaction time of polydopamine-modified agar nanocellulose and octadecylamine) of 5 h, laccase was added at amounts of 0.05 U / mL, 0.1 U / mL, 0.15 U / mL, 0.2 U / mL, and 0.25 U / mL, respectively, and superhydrophobic nanocellulose-based materials were prepared according to the above laccase catalysis method, and their contact angles were measured. The results were recorded in Figure 1 A.

[0031] like Figure 1 As shown in Figure A, the optimal amount of laccase added to the superhydrophobic nanocellulose-based material is 0.1 U / mL.

[0032] (2) The screening steps for water bath heating time included: under the conditions of fixed laccase addition of 0.1 U / mL, a mass ratio of agar nanocellulose to octadecylamine of 1:4, and a room temperature polymerization time of 5 h, the water bath heating time was adjusted to 0.5 h, 1 h, 1.5 h, 2 h, and 2.5 h respectively. Superhydrophobic nanocellulose-based materials were prepared according to the above laccase catalysis method, and their contact angles were measured. The results were recorded in [the table / document name missing]. Figure 1 B.

[0033] like Figure 1 As shown in B, the optimal water bath heating time for the hydrophobic effect of superhydrophobic nanocellulose-based materials is 1 hour.

[0034] (3) The screening steps for the mass ratio of agar-agar nanocellulose to octadecylamine included: under the conditions of fixed laccase addition of 0.1 U / mL, water bath heating time of 1 h, and room temperature polymerization time of 5 h, the mass ratio of agar-agar nanocellulose to octadecylamine was adjusted to 1:2, 1:3, 1:4, 1:5, and 1:6, respectively. Superhydrophobic nanocellulose-based materials were prepared according to the above laccase-catalyzed method, and their contact angles were measured. The results were recorded in […]. Figure 1 C.

[0035] like Figure 1 As shown in C, the optimal mass ratio of agar nanocellulose to octadecylamine for the hydrophobic effect of superhydrophobic nanocellulose-based materials is 1:4.

[0036] (4) The screening steps for room temperature polymerization time included: under the conditions of fixed laccase addition of 0.1 U / mL, water bath heating time of 1 h, and mass ratio of agar nanocellulose to octadecylamine of 1:4, the room temperature polymerization time was adjusted to 2 h, 3 h, 4 h, 5 h, and 6 h respectively. Superhydrophobic nanocellulose-based materials were prepared according to the above laccase-catalyzed method, and their contact angles were measured. The results were recorded in […]. Figure 1 D.

[0037] like Figure 1 As shown in D, the room-temperature polymerization time of polydopamine-modified agar nanocellulose and octadecylamine has the best effect on the hydrophobicity of the superhydrophobic nanocellulose-based material, with 5 hours being optimal.

[0038] Therefore, this invention analyzes the influence of each parameter on the contact angle through single-factor experiments, and selects the optimal process conditions for the laccase catalysis method as follows: laccase addition amount of 0.1 U / mL, water bath heating time of 1 h, mass ratio of agar nanocellulose to octadecylamine of 1:4, and room temperature reaction polymerization time of 5 h. Subsequent experiments were then conducted.

[0039] Characterization analysis The following tests and analyses were conducted on the following materials: agar-agar nanocellulose (denoted as TOCN), the superhydrophobic nanocellulose-based antifouling material prepared under optimal process conditions in Example 1 (denoted as IOPTE), the superhydrophobic nanocellulose-based material prepared without EGCG (denoted as IOPT), the agar-agar nanocellulose-based antifouling coating prepared under optimal process conditions by the "one-pot method" of patent CN119432169A (denoted as OPTE), and the agar-agar nanocellulose-based superhydrophobic coating without EGCG (denoted as OPT).

[0040] (1) Fourier transform infrared spectroscopy analysis TOCN, IOPTE, IOPT, OPT, and OPT, prepared under optimal process conditions, were each mixed with spectral-grade potassium bromide at a mass ratio of 1:100, thoroughly ground in an agate mortar, and then dried. Subsequently, the mixture was pressed into transparent sheets using a tablet press and then pressed at 500–4000 cm⁻¹. -1 Fourier transform infrared spectral data were acquired within the wavenumber range to analyze the chemical structural characteristics of the samples.

[0041] The results are as follows Figure 2 As shown, the polydopamine layer generated by the laccase catalysis method in Example 1 is more uniform and dense. After covering the surface of nanocellulose, it can more fully expose the quinone structural features, thereby enhancing the 1621 cm⁻¹ structure. -1 The signal at the location. In contrast, the simultaneous reaction of dopamine self-polymerization and octadecylamine grafting in the "one-pot method" may lead to a loose structure or defects, partially obscuring the vibrational signal of the quinone structure.

[0042] (2) X-ray diffraction analysis The phase compositions of TOCN, IOPTE, IOPT, OPT, and OPT prepared under optimal process conditions were characterized using a multifunctional X-ray diffractometer (XRD). The test conditions were set as follows: scan speed 5° / min, scan angle range 10°–50°.

[0043] The results are as follows Figure 3 As shown, the crystallinity of the coating (OPT) prepared by the "one-pot method" (65.59%) is lower than that of the material prepared by the laccase-catalyzed method (IOPT) (73.994%), and the crystallinity of the material after adding the antifouling agent (IOPTE) is 70.19%. The amount of antifouling agent added is relatively small, resulting in minimal change in crystallinity. The laccase-catalyzed method of this invention generates a more uniform and dense polydopamine layer through a stepwise reaction, promoting the ordered arrangement and interaction between molecules, thereby improving the crystallinity of the coating.

[0044] (3) Thermogravimetric analysis 10 mg of TOCN, IOPTE, IOPT, OPT and OPT prepared under optimal process conditions were weighed and placed in a crucible. The crucible was heated from room temperature (25°C) to 600°C at a heating rate of 10°C / min under nitrogen protection, and the mass change curves were recorded in real time.

[0045] The results are as follows Figure 4 As shown, between 200℃ and 500℃, the coatings (OPT, OTE) prepared by the "one-pot method" showed a significant decrease in weight, while the materials prepared by the laccase catalysis method (IOPT, IOPTE) showed a more stable trend in weight decrease and a lower residual weight rate, indicating that the materials prepared by the laccase catalysis method of the present invention have better thermal stability.

[0046] Application performance testing (1) Self-cleaning performance test IOPTE and IOPT samples prepared under the optimal process conditions in Example 1 were coated onto the surface of an iron sheet substrate with a thickness of 0.6 mm, a width of 25 mm, and a length of 80 mm. Sand and chalk dust were used as simulated contaminants. The coated samples were placed at an angle in a petri dish, and the contaminants were randomly scattered on the surface. The sample surface was rinsed with water using a syringe, and the contaminant removal process was recorded by imaging.

[0047] Test Results Figure 5 The results show that water flow can effectively carry sand and chalk dust off the coating surface, confirming IOPTE ( Figure 5 A) and IOPT Figure 5 B) The coating has significant self-cleaning properties.

[0048] (2) Chemical stability assessment The IOPT and IOPTE samples prepared under the optimal process conditions in Example 1 were tested for resistance to salt ions and acid and alkali.

[0049] For the salt ion resistance test, the coated samples were immersed in 1.5wt%, 3.5wt%, and 5.5wt% NaCl solutions, respectively. After 3 days, the samples were removed, washed with distilled water, and dried for 30 minutes. The contact angle of a 3μL water droplet was then measured.

[0050] Figure 6 Results A show that the water contact angle of the coating remained stable after immersion in salt solutions of different concentrations, maintaining good non-wetting properties.

[0051] The acid and alkali resistance test uses solutions with pH=1, pH=7 and pH=13 as the medium, and the test method is the same as the salt ion resistance test.

[0052] Figure 6 Results B show that the coating maintains a stable water contact angle in strong acid, neutral and strong alkali environments, demonstrating excellent chemical stability.

[0053] (3) Verification of the universality of the substrate The IOPT and IOPTE prepared under the optimal process conditions in Example 1 were coated on the surfaces of five different substrates: glass, iron sheet, A4 paper, cotton and filter paper. After drying in an oven for 10 hours, 5 μL of Sprite, milk, coffee and tea were added to each substrate for testing.

[0054] The results are as follows Figure 7 As shown, the coatings on all substrates exhibit good hydrophobic properties to different liquids.

[0055] (4) Evaluation of actual pollution prevention effect Indoor panel experiments were conducted using natural seawater collected from the sea area of ​​Changle District, Fuzhou City, Fujian Province. Samples (0.6 mm × 25 mm × 80 mm) coated with IOPT and IOPTE prepared under the optimal process conditions of Example 1 were vertically immersed in the seawater environment for 30 days, and the surface changes of the samples were photographed and recorded.

[0056] Test results showed that the blank iron sheet had obvious rust and dirt on its surface. Figure 8 A); The surface of the sample without ECGG addition had a large amount of contamination ( Figure 8 B); and the surface contaminants of the superhydrophobic nanocellulose-based antifouling material samples prepared in this invention are significantly reduced ( Figure 8 C), which shows excellent anti-fouling effect.

[0057] In summary, the present invention has the following advantages: This invention employs a laccase catalytic process. By precisely controlling the amount of laccase added, the water bath heating time, the mass ratio of agar nanocellulose to octadecylamine, and the room temperature reaction polymerization time of polydopamine and octadecylamine, a superhydrophobic coating with a surface microstructure was successfully prepared. This coating can effectively repel water and dirt, achieving a self-cleaning effect, thereby reducing the frequency of cleaning and maintenance costs, and bringing convenience to users.

[0058] The superhydrophobic nanocellulose-based antifouling material of this invention not only demonstrates advantages in high efficiency and environmental friendliness in its preparation process, but also achieves excellent performance in terms of superhydrophobicity, self-cleaning, acid and alkali resistance, and salt resistance. These characteristics give this invention broad application prospects in the field of environmentally friendly materials, providing strong technical support for achieving green chemistry and sustainable development goals.

[0059] 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 present invention has been described in detail with reference to the foregoing embodiments, 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 scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing superhydrophobic nanocellulose-based antifouling materials using laccase catalysis, characterized in that, Includes the following steps: S1. Dissolve the agar nanocellulose in water by ultrasonication, add laccase and dopamine, adjust the pH to 5.5, and heat in a water bath to obtain polydopamine-modified agar nanocellulose. S2. Dissolve octadecylamine in anhydrous ethanol by ultrasonication, add water and the polydopamine-modified agar nanocellulose, and polymerize at room temperature to obtain a superhydrophobic nanocellulose-based material. Add EGCG and mix to obtain a superhydrophobic nanocellulose-based antifouling material.

2. The method for preparing superhydrophobic nanocellulose-based antifouling materials by laccase catalysis as described in claim 1, characterized in that, In step S1, the amount of laccase added is 0.05-0.25 U / mL; the water bath heating time is 0.5-2.5 h; In step S2, the mass ratio of agar nanocellulose to octadecylamine is 1:2-6; the polymerization time at room temperature is 2-6 hours.

3. The method for preparing superhydrophobic nanocellulose-based antifouling materials by laccase catalysis as described in claim 2, characterized in that, Single-factor experiments were conducted, using the contact angle of the superhydrophobic nanocellulose-based material as an indicator, to screen the optimal amount of laccase, water bath heating time, mass ratio of agar nanocellulose to octadecylamine, and room temperature reaction polymerization time.

4. The method for preparing superhydrophobic nanocellulose-based antifouling materials by laccase catalysis as described in claim 3, characterized in that, The optimal process conditions are: laccase addition of 0.1 U / mL, water bath heating time of 1 h, mass ratio of agar nanocellulose to octadecylamine of 1:4, and room temperature polymerization time of 5 h.

5. The method for preparing superhydrophobic nanocellulose-based antifouling materials by laccase catalysis as described in claim 1, characterized in that, In step S1, the mass ratio of the agar nanocellulose to the dopamine is 1:1.5-2.

5.

6. The method for preparing superhydrophobic nanocellulose-based antifouling materials by laccase catalysis as described in claim 1, characterized in that, In step S1, the water bath heating temperature is 45-50℃.

7. The method for preparing superhydrophobic nanocellulose-based antifouling materials by laccase catalysis as described in claim 1, characterized in that, In step S2, the amount of EGCG added is 2-4 wt% of the mass of the superhydrophobic nanocellulose-based material.

8. The method for preparing superhydrophobic nanocellulose-based antifouling materials by laccase catalysis as described in claim 1, characterized in that, In step S1 and / or step S2, the conditions for ultrasonic dissolution are: ultrasonic power of 300-400W, ultrasonic frequency of 25-30KHz, ultrasonic temperature of 25-35℃, and ultrasonic time of 20-40min.

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