Preparation and application of nano-regulated autocrine antifouling coating

Abstract

The invention belongs to the technical field of marine organism fouling protection, and particularly discloses a preparation method of a nano-regulation autocrine antifouling coating, which mainly comprises two core process steps: 1, preparation of an organic silicon polymer based on reversible dynamic hydrogen bond crosslinking, and 2, preparation of a smooth organic silicon antifouling coating injected with a lubricating liquid. According to the system, a dynamic hydrogen bond design principle and a smooth surface liquid autocrine mechanism are fused, a polymer cross-linked network matrix is constructed, and nucleation and maturation of lubricating liquid droplets are promoted by utilizing dynamic hydrogen bonds in a prepolymer at room temperature, so that a discrete droplet embedded structure is formed. The problems that on-site construction and the construction technology of the coating are complex, and a porous structure with the unsuitable pore size on the surface of the coating provides hiding and adhering places for fouling organisms are solved. The coating can effectively prevent attachment of various fouling organisms such as microbial bacteria, mussels and barnacles, and a novel coating solution with a long-acting static fouling protection function is provided for marine facilities.

Description

Technical Field

[0001] The present invention belongs to the technical field of marine biofouling prevention, and particularly relates to the preparation and application of a nano-regulated self-secreting antifouling coating. Background Art

[0002] Biofouling refers to the attachment and growth of marine organisms on artificial structures, which may lead to performance degradation and damage. Such fouling involves a variety of organisms, including microorganisms such as bacteria and diatoms, as well as large organisms such as barnacles and mussels. They not only increase the navigation resistance, reduce the efficiency of the unit, but also may cause corrosion, increase the maintenance cost, and even lead to species invasion. The development of antifouling technology has evolved from toxic paints to self-polishing TBT copolymer paints and then to low-toxicity paints. Currently, antifouling coatings have become the mainstream due to their extensive application effects, and their mechanism of action is to kill the larvae of attached organisms by releasing poisons. However, this method has environmental risks, such as metal ion deposition and the poisoning of non-target organisms.

[0003] The fouling-release marine antifouling coating exhibits significant advantages in preventing the attachment of marine fouling organisms due to its unique low surface energy property. The core of this type of coating lies in its extremely low surface energy, which makes it difficult for marine organisms to firmly attach to it, thus achieving an effective antifouling effect. Silicone materials, especially polydimethylsiloxane (PDMS), have become the preferred resin materials for preparing such antifouling coatings due to their unique molecular structure and a series of excellent physical and chemical properties such as low glass transition temperature, high and low temperature stability, and strong antioxidant properties. However, it has problems such as poor antifouling performance under static conditions, poor long-term stability and durability. Therefore, researchers simulate the dynamically updated surface of fish bodies in nature and inject lubricating fluid into the fouling-release antifouling coating. The mucus secreted by the coating surface and the scouring action of water flow are used to hinder the attachment and growth of fouling organisms. For example, Chinese Patent CN111423816A discloses a method for preparing a liquid-containing coating with a self-secreting function and a super-smooth surface, which includes two steps: preparing a linear silicone solution and preparing the coating. First, prepare and mix the linear silicone solution and the active small molecule solution, then drop it onto the inorganic substrate and volatilize it, and then immerse it in the lubricant and swell it at a constant temperature. This method can effectively prepare a liquid-containing coating with a super-smooth surface, and supplement the loss of liquid droplets inside the coating by swelling, extend the service life, and improve the use efficiency. However, the technology of injecting lubricating fluid into the matrix by swelling still has many deficiencies in practical applications: the stability of the lubricating layer is poor, it is easy to be damaged, the mechanical stability is insufficient, the preparation process is complex and the cost is high, the oil fixing performance is weak, the environmental adaptability needs to be improved, it may cause environmental pollution, and it is difficult to control the coating thickness. These problems limit its application in terms of stability, cost-effectiveness and environmental friendliness, and further research is needed to overcome these challenges. In addition, the method of secreting the surface lubricating fluid of self-secreting polydimethylsiloxane usually relies on the encapsulation and release of the liquid from the bulk shell compartment of the coating. For example, Chinese Patent CN109453966A discloses a long-acting protective liquid self-secreting super-smooth coating, which consists of three layers of elastic porous membranes: a bottom layer of macroporous oil storage, an upper layer of controlled-release oil liquid, and a surface layer of micro-nano liquid-repellent oil storage. This coating can automatically supplement the surface oil film, release corrosion inhibitors and bactericides with the release of oil, and enhance the protection. The external force promotes deformation and secretes oil, maintaining a stable oil layer, and significantly extending the service life, which is applicable to fields such as anti-corrosion, antifouling, and anti-icing. However, this secretion method usually cannot finely and continuously adjust the secretion process, resulting in a short antifouling period, and the oil storage cavity left after the secretion of the lubricating oil in the coating is conducive to the attachment and growth of fouling organisms. Therefore, the current key research direction of marine antifouling coatings focuses on developing more efficient, broader-spectrum and more durable antifouling materials. Especially for static marine facilities, it is particularly important to develop materials and technologies that can maintain long-term protective performance in a static environment. This not only helps to extend the service life of marine facilities, reduce maintenance costs, but also effectively protects the marine ecological environment and provides strong support for the sustainable utilization of marine resources. Summary of the Invention

[0004] To solve the above technical problems, the present invention proposes a preparation method and application of a nano-regulated self-secreting antifouling coating, so as to achieve precise regulation of the phase separation behavior of secreted substances in the coating matrix, endow the coating with the ability of continuous self-regulated liquid release, and thus significantly improve the efficiency and durability of the antifouling coating in resisting the attachment of various fouling organisms such as microbial bacteria and mussels.

[0005] The preparation method of the nano-regulated self-secreting antifouling coating of the present invention includes the following steps:

[0006] S1. Preparation of organosilicon polymer based on reversible dynamic hydrogen bond crosslinking:

[0007] Add aminopropyl-terminated polydimethylsiloxane and hexamethylene diisocyanate to a tetrahydrofuran solution, stir at room temperature and then let stand to obtain an organosilicon polymer based on reversible dynamic hydrogen bond crosslinking;

[0008] S2. Preparation of a smooth organosilicon antifouling coating with lubricant injection:

[0009] S2.1. Completely dissolve the organosilicon polymer based on reversible dynamic hydrogen bond crosslinking obtained in S1 in a tetrahydrofuran solution, inject lubricant, and continuously stir to prepare an organosilicon prepolymer with lubricant injection;

[0010] S2.2. Coat the organosilicon prepolymer with lubricant injection on the surface of the substrate material to obtain a nano-regulated self-secreting antifouling coating.

[0011] Preferably, in S1, aminopropyl-terminated polydimethylsiloxane and hexamethylene diisocyanate are added to the tetrahydrofuran solution according to a molar ratio of 1:1, continuously stirred at room temperature for 3-4 h, and left standing for 96-120 h to obtain an organosilicon polymer based on reversible dynamic hydrogen bond crosslinking.

[0012] Preferably, the linking unit of the reversible dynamic hydrogen bond in S1 is a ureido group.

[0013] Preferably, the average molecular weight (Mn) of the aminopropyl-terminated polydimethylsiloxane in S1 is 1000-27000.

[0014] Preferably, the lubricant in S2.1 is one or a mixture of two or more of inert oil and fat-soluble antioxidant mixed esters.

[0015] Specifically, the lubricant in S2.1 is methyl silicone oil.

[0016] Specifically, the viscosity of the methyl silicone oil in S2.1 is 10-1000 CS.

[0017] Preferably, in S2.2, it is one of glass, 304 / 316 stainless steel, Q235 / Q345 carbon steel, ceramic chips, plastics, and rubbers.

[0018] The present invention also proposes an application of the nano-regulated self-secreting antifouling coating prepared according to the above method in antifouling coating materials.

[0019] The beneficial effects of the present invention are as follows:

[0020] Compared with the prior art, the nano-regulated self-secreting antifouling coating of the present invention combines the dynamic hydrogen bond design concept and the liquid secretion mechanism. Through the design based on the reversible dynamic hydrogen bond mechanism, the droplets of the lubricating liquid are fixed in the coating matrix to form a discrete droplet embedded structure, thereby realizing the precise regulation of the phase separation behavior of the secreted substances in the coating matrix. This design endows the coating with the ability of continuous self-regulating liquid release, thus significantly improving the efficiency and durability of the antifouling coating in resisting the attachment of various fouling organisms such as microbial bacteria and mussels, and providing a new efficient solution for the field of fouling prevention. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for describing the embodiments will be briefly introduced below.

[0022] Figure 1 It is a schematic diagram of the nano-regulated self-secreting antifouling coating described in the present invention.

[0023] Figure 2 It is an image of the original surface (a), cross-section (b), and reset surface (c) (lubricating layer removal - re-secretion) of the nano-regulated self-secreting antifouling coating described in the present invention.

[0024] Figure 3 It is the hydrogen bond cross-linking unit between the molecular chains of the silicone polymer in the nano-regulated self-secreting antifouling coating described in the present invention.

[0025] Description of the Reference Numerals:

[0026] 1 - Substrate; 2 - Organosilicon coating matrix based on hydrogen bond cross-linking; 3 - Lubricating liquid droplet; 4 - Liquid lubricating layer; 5 - Hydrogen bond cross-linking point. Detailed Embodiments

[0027] The following further describes the detailed embodiments of the present invention. It should be noted here that the description of these embodiments is for helping to understand the present invention, but does not constitute a limitation to the present invention.

[0028] Unless otherwise specified, the equipment used in this example, comparative example, and experimental example are all conventional experimental equipment. The materials and reagents used are commercially available without special instructions, and the experimental methods without special instructions are also conventional experimental methods.

[0029] Example 1

[0030] A preparation method of a nano-regulated self-secreting antifouling coating includes the following steps:

[0031] Restore the aminopropyl double-capped polydimethylsiloxane (average Mn~2500) and hexamethylene diisocyanate (HDI) stored in the refrigerator (2-5°C) to room temperature. According to a molar ratio of 1:1, add 8-10 mL of tetrahydrofuran (THF) solution, continuously stir at room temperature for 3-4 h, and let it stand (at room temperature) for 96 h to obtain an organosilicon polymer based on reversible dynamic hydrogen bond crosslinking; then, weigh 0.25 g of the above-prepared organosilicon polymer, completely dissolve it in 1725 μL of tetrahydrofuran solution at room temperature, inject 280 μL of methyl silicone oil (viscosity 10 CS), keep the rotation speed at 500 rpm, and continuously stir for 1 h to prepare a lubricant-injected organosilicon prepolymer; finally, uniformly coat the obtained prepolymer on the surface of the substrate (2.5×7.6 cm 2 ), and the prepared nano-regulated self-secreting antifouling coating and structure are as Figure 1 and 2 shown. Reversible dynamic hydrogen bonds (-HN-C=O-HN-) are formed between the molecular chains of the organosilicon polymer to fix the lubricant droplets in the organosilicon matrix. The droplets are discrete and evenly distributed in the organosilicon coating matrix. The droplets in the coating matrix gradually migrate to the coating surface under the synergistic action of the lubricant and the organosilicon polymer and spread on the surface to form a liquid antifouling lubricating layer. Under the stimulation of the external environment, after the mass loss of the lubricating layer, the lubricant droplets in the matrix are under the nano-regulation of the dynamic hydrogen bonds between the organosilicon molecular chains, and the lubricant gradually diffuses to the coating surface to compensate for the lost lubricating layer. The interaction mechanism between the organosilicon molecular chains is as Figure 3 shown.

[0032] Example 2

[0033] The difference in preparation from Example 1 is that the injected methyl silicone oil (viscosity 10 CS) in this example is 330 μL.

[0034] Example 3

[0035] The difference in preparation from the above example is that the injected methyl silicone oil (viscosity 10 CS) in this example is 380 μL.

[0036] Example 4

[0037] The preparation difference from the above embodiments is that 420 μL of methyl silicone oil (viscosity 10 CS) is injected in this embodiment.

[0038] Experimental Example 1

[0039] The static contact angles of the smooth surface of the silicone (PDMS) elastomer, the silicone coating without lubricant injection prepared in Examples 1, 2, 3 or 4, and the antifouling coating surface prepared in Examples 1 to 4 were measured with a static contact angle measuring instrument. The results are shown in Table 1.

[0040] Table 1 Static water contact angles of each coating

[0041]

[0042] It can be seen from Table 1 that the fouling release type PDMS coating and the silicone coating without lubricant injection belong to non-superhydrophobic coatings, and mainly rely on the impact of external water flow to remove the attached fouling organisms, which is not conducive to inhibiting the attachment of microscopic fouling organisms. The surface of the lubricant-injected silicone antifouling coating is covered with a liquid lubricating layer, which can inhibit the recognition of fouling organisms and resist the attachment of microscopic and macroscopic fouling organisms. The contact angles of the antifouling coatings in Examples 1 to 4 in the table show a gradually increasing trend. The contact angle of Example 4 is 109.7°, which is between the silicone coating without lubricant injection and the fouling release type PDMS coating, indicating that the surface of the antifouling coating in the example secretes a liquid lubricating layer, which can enhance the antifouling attachment ability of the coating.

[0043] Experimental Example 2

[0044] In this experimental example, the antifouling performance of the antifouling coating was detected with newly cultivated microscopic fouling organisms (E. coli, S. aureus) and macroscopic fouling organisms (V. atrata). The smooth silicone elastomer and the silicone coating based on reversible dynamic hydrogen bond crosslinking prepared in Examples 1, 2, 3 or 4 were used as the control experimental groups, and were compared with the lubricant-injected silicone antifouling coatings prepared in Examples 1 to 4 for the attachment tests of microscopic and macroscopic fouling organisms. The test results are shown in Table 2.

[0045] Table 2 Quantitative analysis by spectrophotometer and counting method to statistically analyze the attachment of fouling organisms on the coating surface

[0046]

[0047] It can be seen from the above table that compared with the PDMS and the silicone coating without lubricant injection, no obvious attachment of microscopic fouling organisms and macroscopic fouling organisms was observed on the surface of the lubricant-injected silicone antifouling coating, indicating that the antifouling performance of this antifouling coating is better than that of the control experimental group coatings.

[0048] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification.

Claims

1. A method for preparing a nano-regulated autocrine antifouling coating, characterized in that: The following steps are involved: S1. Preparation of silicone polymers based on reversible dynamic hydrogen bond crosslinking: Adding aminopropyl di-terminated polydimethylsiloxane and hexamethylene diisocyanate into a tetrahydrofuran solution, stirring at room temperature and then standing to prepare an organosilicon polymer based on reversible dynamic hydrogen bond crosslinking; S2. Preparation of Lubricating Liquid Infused Smooth Silicone Antifouling Coating: S2.1, completely dissolving the organosilicon polymer based on reversible dynamic hydrogen bond cross-linking obtained in S1 in a tetrahydrofuran solution, injecting a lubricating liquid, and continuously stirring to prepare a lubricating liquid-injected organosilicon prepolymer; S2.

2. The silicone prepolymer injected with lubricating liquid is coated on the surface of the base material to obtain a nano-regulated autocrine antifouling coating.

2. The method for preparing the nano-regulated autocrine antifouling coating according to claim 1, characterized in that: The aminopropyl di-terminated polydimethylsiloxane and hexamethylene diisocyanate in S1 are added into tetrahydrofuran solution in a molar ratio of 1:1, stirred continuously for 3 to 4 hours at room temperature, and allowed to stand for 96 to 120 hours to obtain an organosilicon polymer based on reversible dynamic hydrogen bond crosslinking.

3. The method for preparing the nano-regulated autocrine antifouling coating according to claim 2, characterized in that: The connecting unit of the reversible dynamic hydrogen bond in S1 is a urea group.

4. The method for preparing the nano-regulated autocrine antifouling coating according to claim 3, characterized in that: The average molecular weight (Mn) of the aminopropyl-terminated polydimethylsiloxane in S1 is 1,000 to 27,000.

5. The method for preparing the nano-regulated autocrine antifouling coating according to claim 1, characterized in that: The lubricating liquid in S2.1 is one or a mixed ester of two or more of an inert oil or a fat-soluble antioxidant.

6. The method for preparing the nano-regulated autocrine antifouling coating according to claim 5, characterized in that: The lubricating liquid in S2.1 is methyl silicone oil.

7. The method for preparing the nano-regulated autocrine antifouling coating according to claim 6, characterized in that: The viscosity of the methyl silicone oil in S2.1 is 10-1000CS.

8. The method for preparing the nano-regulated autocrine antifouling coating according to claim 1, characterized in that: The S2.2 is one of glass, 304 / 316 stainless steel, Q235 / Q345 carbon steel, ceramic sheet, plastic, and rubber.

9. Use of the nano-regulated autocrine antifouling coating prepared according to any one of claims 1 to 8 in anti-biofouling coating materials.

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