Tannic acid-assisted antifouling coating for internal seawater system as well as preparation method and application of tannic acid-assisted antifouling coating
By combining tannic acid, hydrophilic active substances and protease for self-assembly technology, a green and environmentally friendly antifouling coating was prepared, which solved the problems of difficult construction and environmental pollution of existing coatings and achieved a highly efficient antifouling effect on complex components.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTH CHINA UNIV OF TECH
- Filing Date
- 2026-02-05
- Publication Date
- 2026-05-08
AI Technical Summary
Existing antifouling coatings pose pollution problems in marine environments and are difficult to apply, failing to meet the construction requirements of marine pipeline systems and exhibiting poor antifouling performance.
By combining tannic acid, hydrophilic active substances, and proteases, an antifouling coating is formed through self-assembly. The green and environmentally friendly antifouling coating is prepared by utilizing the anchoring effect of tannic acid, the linking effect of hydrophilic active substances, and the bactericidal effect of proteases.
It enables the self-assembly of antifouling coatings on various substrate surfaces, is simple to apply, has good antifouling effect, is environmentally friendly, is suitable for complex irregular components, and its degradation products are harmless.
Smart Images
Figure CN121991545A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of antifouling materials, specifically relating to a tannic acid-assisted antifouling coating for inland seawater systems, its preparation method, and its application. Background Technology
[0002] Marine fouling organisms refer to biofouling formed by the adsorption, growth, and reproduction of marine microorganisms, animals, and plants on the surfaces of marine engineering equipment and facilities. The attachment and growth of these organisms seriously affect the safe and long-term operation of marine engineering equipment. Specifically, fouling organisms increase the weight and roughness of ships, increasing their navigation resistance and reducing their speed and maneuverability; they can induce metal corrosion in offshore drilling platforms, wave power generation platforms, and other devices, posing safety hazards; and they can clog the mesh of aquaculture tanks, leading to the death of commercially valuable fish due to oxygen depletion or environmental degradation. In the process of fouling organism attachment, contact between the organisms and the material surface is the primary stage of fouling formation. Therefore, antifouling measures in the early stages include preventing contact between the fouling organisms and the material surface or killing the fouling organisms already attached to the material surface.
[0003] Currently, coating is the most widely used and effective antifouling technology. It involves mixing metallic or organic antifouling agents with resin to form an antifouling paint, which is then fixed to the surface of equipment and facilities using a primer and a bonding agent. Despite its excellent antifouling effect, metallic or organic antifouling agents inevitably release into seawater, damaging the marine ecosystem and affecting the growth and reproduction of non-target organisms. Therefore, the development of green and environmentally friendly coatings is urgently needed. On the other hand, different application environments present certain challenges to coating application. For example, in the winding and narrow navigation systems of ships, the narrow inner walls of the pipes, the complexity of the system, and the numerous irregularly shaped components make coating application difficult. Furthermore, the effectiveness of antifouling coatings typically does not exceed 5 years, and recoating inside the pipes is not possible, thus failing to match the maintenance cycle of the ship's piping system.
[0004] Therefore, it is necessary to develop a green and environmentally friendly antifouling coating that has bactericidal effects and is easy to apply, so that it can be used in special components such as marine pipeline systems and has antifouling effects. Summary of the Invention
[0005] To address the shortcomings of existing antifouling coating technologies, the primary objective of this invention is to provide a tannic acid-assisted antifouling coating for inland seawater systems, its preparation method, and its application. This preparation method is simple to operate, low in cost, and applicable to antifouling coatings on various substrates and scenarios, demonstrating versatility. The prepared antifouling coating fully utilizes the specific and efficient characteristics of proteases, effectively killing fouling organisms and preventing their adhesion. Both the protease and the film-forming material are derived from nature, making it environmentally friendly, and the degradation products do not pollute the environment.
[0006] A second objective of this invention is to provide a tannic acid-assisted antifouling coating for inland seawater systems prepared by the above-described preparation method.
[0007] A third objective of this invention is to provide the application of the above-mentioned tannic acid-assisted antifouling coating for inland seawater systems.
[0008] The primary objective of this invention can be achieved through the following technical solutions: A method for preparing a tannic acid-assisted antifouling coating for an inland seawater system includes the following steps: (1) Preparation of tannic acid modified coating: The pretreated substrate is immersed in a tannic acid solution with a mass concentration of 1-10 mg / mL, incubated, washed, and the surface is dried to obtain a tannic acid modified coating. (2) Preparation of hybrid hydrophilic modified coating: The tannic acid modified coating obtained in step (1) is immersed in a hydrophilic active substance solution with a mass concentration of 1-10 mg / mL, incubated, washed, and the surface is dried to obtain a hybrid hydrophilic modified coating; the hydrophilic active substance is at least one of polyethyleneimine, polyvinyl alcohol, polyethylene glycol, and aspartic acid. (3) Preparation of tannic acid-assisted antifouling coating for inland seawater system: After activating the hybrid hydrophilic modified coating in step (2) with an activator solution with a mass concentration of 0.01-0.1 mg / mL, it is then immersed in a protease solution with a mass concentration of 1-10 mg / mL to fix the protease on the substrate surface, thereby obtaining a tannic acid-assisted antifouling coating for inland seawater system; the activator is at least one of glutaraldehyde, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide / N-hydroxysuccinimide, and genipin; the protease is at least one of lysozyme, alkaline protease, trypsin, pepsin, proteinase K, and subtilisin.
[0009] Preferably, the substrate in step (1) is a metal substrate or a non-metal substrate; the metal substrate is one of titanium alloy, copper alloy or steel plate; the non-metal substrate is one of glass, ceramic, polytetrafluoroethylene or nylon.
[0010] Preferably, the incubation temperature in steps (1), (2) and (3) is 20℃~30℃, and the incubation time is 0.5h-4h.
[0011] Preferably, when the substrate is a metal substrate, the method for surface pretreatment of the metal substrate includes the following steps: a. Use 180-2000 grit sandpaper to sand the surface of the substrate in sequence; b. Polish the substrate treated in step (a) sequentially using 2.5-10 mesh polishing compound; c. Rinse the substrate treated in step (b) with at least one of seawater, deionized water, PBS, or Tris-HCl buffer solution to remove excess polishing paste from the surface. d. Clean the substrate treated in step (c) with acetone for 20-60 minutes, then clean it with ethanol for 20-60 minutes, and finally purge it with nitrogen.
[0012] Preferably, the activation method in step (3) is as follows: the prepared activator solution is coated with the hybrid hydrophilic modified coating in step (2) using a dropper, and incubated at 20℃~30℃ for 0.5h-4h. After incubation, it is washed three times with artificial seawater.
[0013] Preferably, the activity of the protease in step (3) is 12.6 U / mg.
[0014] Preferably, the tannic acid solution in step (1) is prepared by dissolving tannic acid in a solvent and stirring until homogeneous; the hydrophilic active substance solution in step (2) is prepared by dissolving hydrophilic active substance in a solvent and stirring until homogeneous; the protease solution in step (3) is prepared by dissolving protease in a solvent and stirring until homogeneous; and the activator solution is prepared by dissolving activator in a solvent and stirring until homogeneous.
[0015] Preferably, the solvent is at least one of deionized water, artificial seawater, Tris-HCl solution, and PBS buffer.
[0016] The second objective of this invention can be achieved through the following technical solution: A tannic acid-assisted antifouling coating for an inland seawater system is prepared by the above-described method.
[0017] Preferably, the adsorption capacity of the tannic acid-assisted antifouling coating for the inland seawater system is 2000~4500 Hz.
[0018] Preferably, the water contact angle of the tannic acid-assisted antifouling coating for the inland seawater system is 31~34°.
[0019] The third objective of this invention can be achieved through the following technical solutions: A tannic acid-assisted antifouling coating for inland seawater systems is applied to the antifouling of irregularly shaped and small components in marine equipment and facilities in a real marine environment.
[0020] The tannic acid-assisted antifouling coating for inland seawater systems provided by this invention is mainly self-assembled through the anchoring effect of tannic acid, the linking effect of hydrophilic active substances, and the bactericidal effect of proteases. This antifouling coating has the following characteristics: tannic acid is a natural polyphenol with good hydrophilic properties, rich in catechol groups, which can anchor to the substrate through various forces; the hydrophilic active substances, while improving the surface hydrophilicity and enhancing the antifouling effect, also introduce a large number of enzyme-carrying sites; the protease is fixed on the coating surface, effectively hydrolyzing proteins in the biofilm matrix, disintegrating the biofilm structure, exposing bacteria, and thus disrupting biofilm formation. Furthermore, the materials used, tannic acid and protease, are naturally derived biomolecules with polymeric structures, are environmentally friendly, and the degraded substances will not harm the marine ecological environment.
[0021] The present invention has the following advantages and beneficial effects compared with the prior art: (1) This invention utilizes the reaction of tannic acid, hydrophilic active substances, and proteases to prepare a self-forming tannic acid-assisted antifouling coating for inland seawater systems. This preparation method can achieve in-situ film formation on various substrate surfaces, offering good versatility and simple operation. Through trial and screening, the introduction of tannic acid into the system allows it to be anchored to the substrate surface by various intermolecular forces, enhancing the adhesion of the antifouling coating. The addition of hydrophilic active substances effectively prevents the direct reaction between tannic acid and proteases, which would cause the proteases to open their domains and lose activity. Simultaneously, as an "intermediate layer," it effectively connects tannic acid and proteases through hydrogen bonds, van der Waals forces, and intermolecular forces, providing multiple sites for protein fixation. The addition of proteases effectively prevents fouling organisms from forming films on the coating surface. (2) Conventional antifouling coatings are simple to operate and easy to apply when coating large, flat areas. However, they are more difficult to apply to marine pipeline systems and irregularly shaped components, and the coating thickness cannot be guaranteed to be uniform during the application process. The antifouling coating described in this invention can self-assemble to form an antifouling coating on the substrate surface, and the material is easily soluble in water. Therefore, it can be prepared and used immediately to meet different construction conditions and needs. (3) Most of the antifouling agents added to existing antifouling coatings are metallic or organic antifouling agents, which may pollute the marine environment in actual marine applications, thereby affecting the growth of marine organisms. The antifouling coating described in this invention uses protease for antifouling, which effectively avoids the release of heavy metals and organic materials, and the degradation products of the coating itself will not have an impact on the environment. The antifouling coating prepared by this method is green, environmentally friendly and environmentally friendly. (4) The antifouling coating described in this invention patent is applicable to a variety of substrates due to the strong adsorption capacity of tannic acid, and can meet the antifouling requirements of various substrate surfaces and internal structures in real marine environments. Attached Figure Description
[0022] Figure 1 This is a diagram illustrating the preparation process of the tannic acid-assisted antifouling coating for inland seawater systems described in this invention. Figure 2 The image shows the adsorption amount of the tannic acid-assisted antifouling coating for the inland seawater system described in Example 1 on the titanium alloy surface. Figure 3 This is a graph showing the variation of the water contact angle on the surface of the tannic acid-assisted antifouling coating for the inland seawater system described in Example 1; Figure 4 The diagram shows the antibacterial properties of the tannic acid-assisted antifouling coating for the inland seawater system described in Example 1. Figure 5 This is a diagram illustrating the anti-algae performance of the tannic acid-assisted antifouling coating for the inland seawater system described in Example 1. Detailed Implementation
[0023] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.
[0024] Unless otherwise specified in the embodiments of this invention, conventional conditions or conditions recommended by the manufacturer shall apply. All raw materials and reagents used, unless otherwise specified, are commercially available products. All quantities mentioned in the following embodiments refer to parts by weight.
[0025] Example 1
[0026] The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems described in this embodiment includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with 120 grit, 400 grit, 1200 grit and 2000 grit sandpaper in sequence, and then polished with 10 grit, 5 grit and 2.5 grit polishing paste. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 50 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 25℃ for 1 h. Then it was washed three times with artificial seawater and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Preparation of hybrid hydrophilic modified coating: 50 mg polyethyleneimine and 10 mL artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain polyethyleneimine solution; the coating obtained in step (2) is immersed in polyethyleneimine solution and incubated at 25℃ for 1 h to obtain hybrid hydrophilic modified coating. (4) Preparation of tannic acid-assisted antifouling coating for inland seawater system: 50 mg proteinase K and 10 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain a proteinase solution; 2 mg genipin and 100 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain an activator; the hydrophilic modified coating obtained in step (3) was activated by the activator and then immersed in the proteinase solution and incubated at 25°C for 1 h. After incubation, the coating was washed three times with artificial seawater and then the surface was cleaned with nitrogen to obtain the tannic acid-assisted antifouling coating for inland seawater system.
[0027] like Figure 2 The figure shown is a graph of the adsorption amount of the tannic acid-assisted antifouling coating for the inland seawater system described in this embodiment on the titanium alloy surface. Figure 3 This is a graph showing the variation of the water contact angle on the surface of the tannic acid-assisted antifouling coating for the inland seawater system described in this embodiment; Figure 4 This is a diagram illustrating the antibacterial properties of the tannic acid-assisted antifouling coating for the inland seawater system described in this embodiment. Figure 5 This diagram illustrates the anti-algae performance of the tannic acid-assisted antifouling coating for the inland seawater system described in this embodiment.
[0028] Example 2
[0029] The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems described in this embodiment includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with 120 grit, 400 grit, 1200 grit and 2000 grit sandpaper in sequence, and then polished with 10 grit, 5 grit and 2.5 grit polishing paste. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 100 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 25℃ for 1 h. Then it was washed three times with artificial seawater and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Preparation of hybrid hydrophilic modified coating: 50 mg polyethyleneimine and 10 mL artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain polyethyleneimine solution; the coating obtained in step (2) is immersed in polyethyleneimine solution and incubated at 25℃ for 1 h to obtain hybrid hydrophilic modified coating. (4) Preparation of tannic acid-assisted antifouling coating for inland seawater system: 50 mg proteinase K and 10 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain a proteinase solution; 2 mg genipin and 100 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain an activator; the hydrophilic modified coating obtained in step (3) was activated by the activator and then immersed in the proteinase solution and incubated at 25°C for 1 h. After incubation, the coating was washed three times with artificial seawater and then the surface was cleaned with nitrogen to obtain the tannic acid-assisted antifouling coating for inland seawater system.
[0030] Example 3
[0031] The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems described in this embodiment includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with 120 grit, 400 grit, 1200 grit and 2000 grit sandpaper in sequence, and then polished with 10 grit, 5 grit and 2.5 grit polishing paste. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 10 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 25℃ for 1 h. Then it was washed three times with artificial seawater and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Preparation of hybrid hydrophilic modified coating: 50 mg polyethyleneimine and 10 mL artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain polyethyleneimine solution; the coating obtained in step (2) is immersed in polyethyleneimine solution and incubated at 25℃ for 1 h to obtain hybrid hydrophilic modified coating. (4) Preparation of tannic acid-assisted antifouling coating for inland seawater system: 50 mg proteinase K and 10 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain a proteinase solution; 2 mg genipin and 100 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain an activator; the hydrophilic modified coating obtained in step (3) was activated by the activator and then immersed in the proteinase solution and incubated at 25°C for 1 h. After incubation, the coating was washed three times with artificial seawater and then the surface was cleaned with nitrogen to obtain the tannic acid-assisted antifouling coating for inland seawater system.
[0032] Example 4
[0033] The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems described in this embodiment includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with 120 grit, 400 grit, 1200 grit and 2000 grit sandpaper in sequence, and then polished with 10 grit, 5 grit and 2.5 grit polishing paste. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 50 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 25℃ for 1 h. Then it was washed three times with artificial seawater and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Preparation of hybrid hydrophilic modified coating: 100 mg polyethyleneimine and 10 mL artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain a polyethyleneimine solution; the coating obtained in step (2) is immersed in the polyethyleneimine solution and incubated at 25℃ for 1 h to obtain a hybrid hydrophilic modified coating. (4) Preparation of tannic acid-assisted antifouling coating for inland seawater system: 50 mg proteinase K and 10 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain a proteinase solution; 2 mg genipin and 100 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain an activator; the hydrophilic modified coating obtained in step (3) was activated by the activator and then immersed in the proteinase solution and incubated at 25°C for 1 h. After incubation, the coating was washed three times with artificial seawater and then the surface was cleaned with nitrogen to obtain the tannic acid-assisted antifouling coating for inland seawater system.
[0034] Example 5
[0035] The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems described in this embodiment includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with 120 grit, 400 grit, 1200 grit and 2000 grit sandpaper in sequence, and then polished with 10 grit, 5 grit and 2.5 grit polishing paste. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 50 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 25℃ for 1 h. Then it was washed three times with artificial seawater and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Preparation of hybrid hydrophilic modified coating: 10 mg of polyethyleneimine and 10 mL of artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain a polyethyleneimine solution; the coating obtained in step (2) is immersed in the polyethyleneimine solution and incubated at 25℃ for 1 h to obtain a hybrid hydrophilic modified coating. (4) Preparation of tannic acid-assisted antifouling coating for inland seawater system: 50 mg proteinase K and 10 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain a proteinase solution; 2 mg genipin and 100 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain an activator; the hydrophilic modified coating obtained in step (3) was activated by the activator and then immersed in the proteinase solution and incubated at 25°C for 1 h. After incubation, the coating was washed three times with artificial seawater and then the surface was cleaned with nitrogen to obtain the tannic acid-assisted antifouling coating for inland seawater system.
[0036] Example 6
[0037] The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems described in this embodiment includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with 120 grit, 400 grit, 1200 grit and 2000 grit sandpaper in sequence, and then polished with 10 grit, 5 grit and 2.5 grit polishing paste. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 50 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 25℃ for 1 h. Then it was washed three times with artificial seawater and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Preparation of hybrid hydrophilic modified coating: 50 mg polyethyleneimine and 10 mL artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain polyethyleneimine solution; the coating obtained in step (2) is immersed in polyethyleneimine solution and incubated at 25℃ for 1 h to obtain hybrid hydrophilic modified coating. (4) Preparation of tannic acid-assisted antifouling coating for inland seawater system: 100 mg proteinase K and 10 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain a proteinase solution; 2 mg genipin and 100 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain an activator; the hydrophilic modified coating obtained in step (3) was activated by the activator and then immersed in the proteinase solution and incubated at 25°C for 1 h. After incubation, the coating was washed three times with artificial seawater and then the surface was cleaned with nitrogen to obtain the tannic acid-assisted antifouling coating for inland seawater system.
[0038] Example 7
[0039] The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems described in this embodiment includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with 120 grit, 400 grit, 1200 grit and 2000 grit sandpaper in sequence, and then polished with 10 grit, 5 grit and 2.5 grit polishing paste. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 50 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 25℃ for 1 h. Then it was washed three times with artificial seawater and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Preparation of hybrid hydrophilic modified coating: 50 mg of polyethyleneimine and 10 mL of artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain a polyethyleneimine solution. The coating obtained in step (2) was immersed in the polyethyleneimine solution and incubated at 25°C for 1 h to obtain a hybrid hydrophilic modified coating; (4) Preparation of tannic acid-assisted antifouling coating for inland seawater system: 10 mg proteinase K and 10 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain a proteinase solution; 2 mg genipin and 100 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain an activator; the hydrophilic modified coating obtained in step (3) was activated by the activator and then immersed in the proteinase solution and incubated at 25°C for 1 h. After incubation, the coating was washed three times with artificial seawater and then the surface was cleaned with nitrogen to obtain the tannic acid-assisted antifouling coating for inland seawater system.
[0040] Example 8
[0041] The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems described in this embodiment includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with sandpaper of 120 mesh, 400 mesh, 1200 mesh and 2000 mesh in sequence, and then polished with polishing paste of 10 mesh, 5 mesh and 2.5 mesh. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 50 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 25℃ for 1 h. After that, it was washed with artificial seawater three times and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Preparation of hybrid hydrophilic modified coating: 50 mg polyethyleneimine and 10 mL artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain polyethyleneimine solution; the coating obtained in step (2) is immersed in polyethyleneimine solution and incubated at 25℃ for 1 h to obtain hybrid hydrophilic modified coating. (4) Preparation of tannic acid-assisted antifouling coating for inland seawater system: 50 mg proteinase K and 10 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain a proteinase solution; 1 mg genipin and 100 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain an activator; the hydrophilic modified coating obtained in step (3) was activated by the activator and then immersed in the proteinase solution and incubated at 25°C for 1 h. After incubation, the coating was washed three times with artificial seawater and then the surface was cleaned with nitrogen to obtain the tannic acid-assisted antifouling coating for inland seawater system.
[0042] Example 9
[0043] The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems described in this embodiment includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with sandpaper of 120 mesh, 400 mesh, 1200 mesh and 2000 mesh in sequence, and then polished with polishing paste of 10 mesh, 5 mesh and 2.5 mesh. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 50 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 25℃ for 1 h. After that, it was washed with artificial seawater three times and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Preparation of hybrid hydrophilic modified coating: 50 mg polyethyleneimine and 10 mL artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain polyethyleneimine solution; the coating obtained in step (2) is immersed in polyethyleneimine solution and incubated at 25℃ for 1 h to obtain hybrid hydrophilic modified coating. (4) Preparation of tannic acid-assisted antifouling coating for inland seawater system: 50 mg proteinase K and 10 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain a proteinase solution; 10 mg genipin and 100 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain an activator; the hydrophilic modified coating obtained in step (3) was activated by the activator and then immersed in the proteinase solution and incubated at 25°C for 1 h. After incubation, the coating was washed three times with artificial seawater and then the surface was cleaned with nitrogen to obtain the tannic acid-assisted antifouling coating for inland seawater system.
[0044] Example 10
[0045] The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems described in this embodiment includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with 120 grit, 400 grit, 1200 grit and 2000 grit sandpaper in sequence, and then polished with 10 grit, 5 grit and 2.5 grit polishing paste. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 50 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 20℃ for 1 h. Then it was washed three times with artificial seawater and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Preparation of hybrid hydrophilic modified coating: 50 mg polyethyleneimine and 10 mL artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain a polyethyleneimine solution; the coating obtained in step (2) is immersed in the polyethyleneimine solution and incubated at 20℃ for 1 h to obtain a hybrid hydrophilic modified coating. (4) Preparation of tannic acid-assisted antifouling coating for inland seawater system: 50 mg proteinase K and 10 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain a proteinase solution; 2 mg genipin and 100 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain an activator; the hydrophilic modified coating obtained in step (3) was activated by the activator and then immersed in the proteinase solution and incubated at 20°C for 1 h. After incubation, the coating was washed three times with artificial seawater and then the surface was cleaned with nitrogen to obtain the tannic acid-assisted antifouling coating for inland seawater system.
[0046] Example 11
[0047] The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems described in this embodiment includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with 120 grit, 400 grit, 1200 grit and 2000 grit sandpaper in sequence, and then polished with 10 grit, 5 grit and 2.5 grit polishing paste. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 50 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 30℃ for 1 h. Then it was washed three times with artificial seawater and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Preparation of hybrid hydrophilic modified coating: 50 mg polyethyleneimine and 10 mL artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain a polyethyleneimine solution; the coating obtained in step (2) is immersed in the polyethyleneimine solution and incubated at 30℃ for 1 h to obtain a hybrid hydrophilic modified coating. (4) Preparation of tannic acid-assisted antifouling coating for inland seawater system: 50 mg proteinase K and 10 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain a proteinase solution; 2 mg genipin and 100 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain an activator; the hydrophilic modified coating obtained in step (3) was activated by the activator and then immersed in the proteinase solution and incubated at 30°C for 1 h. After incubation, the coating was washed three times with artificial seawater and then the surface was cleaned with nitrogen to obtain the tannic acid-assisted antifouling coating for inland seawater system.
[0048] Example 12
[0049] The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems described in this embodiment includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with sandpaper of 120 mesh, 400 mesh, 1200 mesh and 2000 mesh in sequence, and then polished with polishing paste of 10 mesh, 5 mesh and 2.5 mesh. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 50 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 25℃ for 0.5 h. After that, it was washed with artificial seawater three times and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Preparation of hybrid hydrophilic modified coating: 50 mg polyethyleneimine and 10 mL artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain polyethyleneimine solution; the coating obtained in step (2) is immersed in polyethyleneimine solution and incubated at 25℃ for 0.5 h to prepare hybrid hydrophilic modified coating. (4) Preparation of tannic acid-assisted antifouling coating for inland seawater system: 50 mg proteinase K and 10 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain a proteinase solution; 2 mg genipin and 100 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain an activator; the hydrophilic modified coating obtained in step (3) was activated by the activator and then immersed in the proteinase solution and incubated at 25°C for 0.5 h. After incubation, the coating was washed three times with artificial seawater and then the surface was cleaned with nitrogen to obtain the tannic acid-assisted antifouling coating for inland seawater system.
[0050] Example 13
[0051] The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems described in this embodiment includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with sandpaper of 120 mesh, 400 mesh, 1200 mesh and 2000 mesh in sequence, and then polished with polishing paste of 10 mesh, 5 mesh and 2.5 mesh. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 50 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 25℃ for 4 h. After that, it was washed with artificial seawater three times and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Preparation of hybrid hydrophilic modified coating: 50 mg polyethyleneimine and 10 mL artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain polyethyleneimine solution; the coating obtained in step (2) is immersed in polyethyleneimine solution and incubated at 25℃ for 4 h to obtain hybrid hydrophilic modified coating. (4) Preparation of tannic acid-assisted antifouling coating for inland seawater system: 50 mg proteinase K and 10 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain a proteinase solution; 2 mg genipin and 100 mL artificial seawater were stirred at a rate of 500-600 r / min for 5-10 min until homogeneous to obtain an activator; the hydrophilic modified coating obtained in step (3) was activated by the activator and then immersed in the proteinase solution and incubated at 25°C for 4 h. After incubation, the coating was washed three times with artificial seawater and then the surface was cleaned with nitrogen to obtain the tannic acid-assisted antifouling coating for inland seawater system.
[0052] Comparative Example 1 The method for preparing the antifouling coating containing protease described in this comparative example includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with sandpaper of 120 mesh, 400 mesh, 1200 mesh and 2000 mesh in sequence, and then polished with polishing paste of 10 mesh, 5 mesh and 2.5 mesh. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 50 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 25℃ for 1 h. After that, it was washed with artificial seawater three times and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Preparation of hydrophilic modified coating: The coating obtained in step (2) is immersed in artificial seawater and incubated at 25°C for 1 hour to prepare the hydrophilic modified coating; (4) Preparation of antifouling coating containing protease: 50 mg proteinase K and 10 mL artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain a protease solution; 2 mg genipin and 100 mL artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain an activator; the hydrophilic modified coating obtained in step (3) is activated by the activator and then immersed in the protease solution and incubated at 25℃ for 1 h. After incubation, the coating is washed three times with artificial seawater and then the surface is cleaned with nitrogen to obtain an antifouling coating containing protease.
[0053] No polyethyleneimine hydrophilic active material was added to this comparative system. The test results show that the direct reaction between tannic acid and proteinase K leads to the inactivation of the proteinase, thus rendering the prepared coating devoid of antifouling properties.
[0054] Comparative Example 2 The method for preparing the antifouling coating containing protease described in this comparative example includes the following steps: (1) Pretreatment of titanium alloy substrate surface: The titanium alloy substrate was polished with 120 grit, 400 grit, 1200 grit and 2000 grit sandpaper in sequence, and then polished with 10 grit, 5 grit and 2.5 grit polishing paste. After that, it was rinsed with artificial seawater. The titanium sheet was placed in a beaker and acetone was added. It was ultrasonically treated for 30 min, and then placed in the acetone solution for ultrasonic treatment for 30 min. Finally, it was cleaned with artificial seawater and dried with nitrogen to obtain the treated titanium alloy substrate. (2) Preparation of tannic acid modified coating: 50 mg tannic acid and 10 mL artificial seawater were stirred at a rate of 500~600 r / min for 5~10 min until uniform to obtain tannic acid solution. The treated titanium alloy substrate was immersed in tannic acid solution and incubated at 25℃ for 1 h. Then it was washed three times with artificial seawater and the surface was dried with nitrogen to obtain tannic acid modified coating. (3) Immerse the coating obtained in step (2) in artificial seawater and incubate at 25°C for 1 hour; (4) Preparation of antifouling coating containing protease: 50 mg proteinase K and 10 mL artificial seawater are stirred at a rate of 500~600 r / min for 5~10 min until homogeneous to obtain a protease solution; the hydrophilic modified coating obtained in step (3) is activated by an activator and then immersed in the protease solution and incubated at 25℃ for 1 h. After incubation, the coating is washed three times with artificial seawater and then the surface is cleaned with nitrogen to obtain an antifouling coating containing protease.
[0055] No activator was added in this comparative system. The test results show that the number of proteinase K grafted on the coating surface was significantly reduced, which reduced the antifouling effect of the prepared coating.
[0056] Performance testing experiment The performance of the antifouling coatings prepared in Examples 1 to 13 and Comparative Examples 1 to 2 was tested under the following conditions: (1) At 25℃, the adsorption capacity of the antifouling coating was tested using QCM-D. The specific results are shown in Table 1. (2) At 25℃, the surface characteristics of the protein-based antifouling coating were tested using a contact angle instrument. The specific results are shown in Table 1. (3) Test method for proteinase K activity: Refer to the national standard GB / T 33410-2016 "Detection method for proteinase K activity in biochemical reagents", add the test solution to casein solution, incubate at 55℃ for 5 min, add trichloroacetic acid, let stand for 5 min, filter, use ultraviolet spectrophotometer to measure the absorbance of the filtrate at 275 nm, obtain the concentration of L-tyrosine according to the standard curve, and calculate the specific activity of proteinase according to the formula. The specific results are shown in Table 1.
[0057] (4) The antibacterial properties of the protein-based antifouling coating were evaluated using the growth of Escherichia coli. The specific results are shown in Table 1.
[0058] (5) The growth of Navicula was used to evaluate the anti-algae performance of the protein-based antifouling coating. The specific results are shown in Table 1.
[0059] Table 1
[0060] As shown in Examples 1 to 13 and Comparative Examples 1 and 2 above, the adsorption frequency of the antifouling coatings prepared in Examples 1 to 14 of this invention reaches 2000~4500 Hz, indicating the successful construction of the antifouling coating. The water contact angle is 31~34°, lower than the blank group, indicating that the substrate surface modified by the coating is more hydrophilic. The protease activity is also greater than 0, indicating that the protein in the coating maintains good activity. At the same time, they all exhibit good antibacterial and anti-algae properties, indicating that the antifouling coating has good antifouling characteristics. The experimental results of Comparative Example 1 show that when there is no hydrophilic active substance in the coating, the direct connection between tannic acid and protease will cause protein inactivation. The experimental results of Comparative Example 2 show that without activation of the hydrophilic layer, the number of linked proteases decreases, thus reducing enzyme activity. Although there is an antifouling effect, the antifouling effect is also reduced.
[0061] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A method for preparing a tannic acid-assisted antifouling coating for an inland seawater system, characterized in that, Includes the following steps, (1) Preparation of tannic acid modified coating: The pretreated substrate is immersed in a tannic acid solution with a mass concentration of 1-10 mg / mL, incubated, washed, and the surface is dried to obtain a tannic acid modified coating. (2) Preparation of hybrid hydrophilic modified coating: The tannic acid modified coating obtained in step (1) is immersed in a hydrophilic active substance solution with a mass concentration of 1-10 mg / mL, incubated, washed, and the surface is dried to obtain a hybrid hydrophilic modified coating; the hydrophilic active substance is at least one of polyethyleneimine, polyvinyl alcohol, polyethylene glycol, and aspartic acid. (3) Preparation of tannic acid-assisted antifouling coating for inland seawater system: After activating the hybrid hydrophilic modified coating in step (2) with an activator solution with a mass concentration of 0.01-0.1 mg / mL, it is then immersed in a protease solution with a mass concentration of 1-10 mg / mL to fix the protease on the substrate surface, thereby obtaining a tannic acid-assisted antifouling coating for inland seawater system; the activator is at least one of glutaraldehyde, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide / N-hydroxysuccinimide, and genipin; the protease is at least one of lysozyme, alkaline protease, trypsin, pepsin, proteinase K, and subtilisin.
2. The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems according to claim 1, characterized in that, The substrate mentioned in step (1) is a metal substrate or a non-metal substrate; the metal substrate is one of titanium alloy, copper alloy or steel plate; the non-metal substrate is one of glass, ceramic, polytetrafluoroethylene or nylon.
3. The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems according to claim 1, characterized in that, The incubation temperature in steps (1), (2) and (3) is 20℃~30℃, and the incubation time is 0.5h-4h.
4. The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems according to claim 1, characterized in that, The activity of the protease in step (3) is 12.6 U / mg.
5. The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems according to claim 1, characterized in that, The tannic acid solution in step (1) is prepared by dissolving tannic acid in a solvent and stirring until homogeneous; the hydrophilic active substance solution in step (2) is prepared by dissolving hydrophilic active substance in a solvent and stirring until homogeneous; the protease solution in step (3) is prepared by dissolving protease in a solvent and stirring until homogeneous; and the activator solution is prepared by dissolving activator in a solvent and stirring until homogeneous.
6. The method for preparing the tannic acid-assisted antifouling coating for inland seawater systems according to claim 5, characterized in that, The solvent is at least one of deionized water, artificial seawater, Tris-HCl solution, and PBS buffer.
7. A tannic acid-assisted antifouling coating for an inland seawater system, characterized in that, It is prepared according to any one of claims 1 to 6.
8. The tannic acid-assisted antifouling coating for inland seawater systems according to claim 7, characterized in that, The adsorption capacity of the tannic acid-assisted antifouling coating for the inland seawater system is 2000~4500 Hz.
9. The tannic acid-assisted antifouling coating for inland seawater systems according to claim 7, characterized in that, The water contact angle of the tannic acid-assisted antifouling coating for the inland seawater system is 31~34°.
10. The application of a tannic acid-assisted antifouling coating for inland seawater systems according to any one of claims 7 to 9 in the antifouling of irregularly shaped and small components in marine equipment and facilities in a real marine environment.