Composite Organic Gel Lubricating Coating for Marine Antifouling and Anticorrosion, Preparation Method and Application

Abstract

The present invention discloses a composite organic gel lubricating coating for marine antifouling and anticorrosion, a preparation method and an application, belonging to the technical field of marine antifouling coatings. The preparation method is as follows: 1) Polyvinyl alcohol and tannic acid are dissolved in an ethanol solution to obtain a hydrogel casting solution; the substrate is immersed in the hydrogel casting solution, taken out and cooled and fixed, and then thermally cross-linked to obtain a gel coating; 2) A vinyl-containing siloxane monomer, a vinyl-containing silicone oil and a silane cross-linking agent containing a hydrosilyl bond are mixed and then a platinum catalyst is added to promote an addition reaction to obtain an organic gel casting solution; 3) The organic gel casting solution is uniformly coated on the surface of the gel coating, and a lubricating fluid is injected into the surface of the cured coating to obtain a composite organic gel lubricating coating. The composite organic gel lubricating coating obtained by the present invention has excellent tensile properties, wear resistance and multiple antifouling properties, and shows broad application prospects in realizing antifouling and anticorrosion on the surface of ships.

Description

Technical Field

[0001] The present invention belongs to the technical field of marine antifouling coatings, and particularly relates to a composite organic gel lubricating coating for marine antifouling and anticorrosion, a preparation method and an application thereof. Background Art

[0002] Marine antifouling technology is an important topic in the fields of ships and marine engineering. With the increase in global trade and the development of marine resources, ships and other marine equipment are immersed in seawater for a long time, resulting in a series of biofouling problems. Biofouling not only increases the resistance of ships, reduces the navigation efficiency, increases fuel consumption, but also corrodes the hull materials and shortens their service life. Compared with the non-fouled hull surface, biofouling will increase the fuel consumption of the global shipping industry and lead to an increase in navigation costs. Therefore, the development of efficient and environmentally friendly antifouling coatings has become a key research direction.

[0003] Traditional antifouling paints often contain heavy metals or organotin compounds, and rely on releasing harmful substances to prevent biological attachment. However, these toxic substances cause serious pollution to the marine ecosystem and have been prohibited from use in many countries and regions. Traditional low surface energy antifouling coatings (SHPS) reduce biological adhesion by reducing the surface energy, but the effect is not good and the durability is poor. Self-polishing antifouling paints continuously release antifouling agents to maintain a smooth surface, but the release rate is not easy to control, and the antifouling agents are easily exhausted after long-term use. Therefore, it is urgent to prepare a new, non-toxic and environmentally friendly antifouling coating.

[0004] In recent years, in order to meet the needs of green technology and sustainable development, a variety of surface coating technologies have been developed, such as lubricating liquid infused porous surfaces (SLIPS) and lubricant infused polymer surfaces (LLS), etc. However, SLIPS has the problem of easy loss of lubricating liquid, while LLS faces the challenge of insufficient durability, resulting in serious loss of lubricant in the porous liquid infused surface. Therefore, in the field of antifouling, it is urgent to develop a new lubricating coating method to ensure long-term and effective antifouling effect. Summary of the Invention

[0005] The purpose of the present invention is to solve the deficiencies in the prior art, and provide a composite organic gel lubricating coating for marine antifouling and anticorrosion, a preparation method and an application thereof. The present invention adopts

[0006] The specific technical solutions adopted by the present invention are as follows:

[0007] In the first aspect, the present invention provides a preparation method for a composite organic gel lubricating coating, and the specific steps are as follows:

[0008] S1: Add polyvinyl alcohol and tannic acid into an ethanol solution, heat it until completely dissolved to obtain a hydrogel casting solution; Immerse a clean substrate into the hydrogel casting solution, take it out and cool and fix it, and then perform thermal cross-linking treatment until the water is completely evaporated to obtain a gel coating;

[0009] S2: Mix a vinyl-containing siloxane monomer, a vinyl-containing silicone oil and a silane cross-linking agent containing a hydrosilyl bond, and add a platinum catalyst to promote the addition reaction to prepare an organic gel casting solution;

[0010] S3: Uniformly coat the organic gel casting solution obtained in step S2 on the surface of the gel coating obtained in step S1, remove the excess organic gel casting solution and then cure it; Inject a lubricating fluid onto the surface of the self-cured coating, remove the excess lubricating fluid to obtain a composite organic gel lubricating coating.

[0011] Preferably, in step S1, the mass ratio of polyvinyl alcohol to tannic acid is 3:(1 - 4).

[0012] Preferably, in step S1, the volume ratio of ethanol to water in the ethanol solution is (4 - 6):(6 - 4).

[0013] Preferably, in step S1, the substrate with the hydrogel casting solution is placed in an ultra-low temperature refrigerator at -80 °C for cooling and fixing.

[0014] Preferably, in step S1, the thermal cross-linking treatment is carried out in an oven, the temperature is set at 40 - 80 °C, and the time is 0.5 - 1 h.

[0015] Preferably, in step S2, the vinyl-containing siloxane monomer uses vinyltrimethoxysilane; the vinyl-containing silicone oil uses vinyl-terminated polydimethylsiloxane; the silane cross-linking agent containing a hydrosilyl bond uses polymethylhydrosiloxane; the mass ratio of vinyl-terminated polydimethylsiloxane, polymethylhydrosiloxane and vinyltrimethoxysilane is 12:20:(1 - 4); the addition amount of the platinum catalyst to polymethylhydrosiloxane is 1:(80 - 120).

[0016] Preferably, in step S3, the curing is carried out in an oven, the temperature is set at 25 - 40 °C, and the time is 12 - 24 h.

[0017] Preferably, in step S3, the lubricating fluid uses polydimethylsiloxane, perfluoropolyether or silicone oil.

[0018] In a second aspect, the present invention provides a composite organic gel lubricating coating prepared by the preparation method described in the first aspect.

[0019] In a third aspect, the present invention provides an application of the composite organic gel lubricating coating described in the second aspect in marine antifouling and anticorrosion, and the composite organic gel lubricating coating is used for antifouling and anticorrosion on the surface of a ship hull.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) For the preparation method of the composite organic gel lubricating coating provided by the present invention, a gradient coupling strategy is adopted to synergistically phase-transition induced polymerization process. Through silane hydrolysis and condensation, an organic gel dominated by silane is adhered to the surface of a hydrogel dominated by a hydrophilic polymer (polyvinyl alcohol / tannic acid) to construct a composite organic gel coating. Confined in-situ grafting is carried out at the water / organic interface to form an organogel network with high entanglement and superlubricity characteristics. The prepared coating has superlubricity characteristics and excellent tensile properties, wear resistance, and multiple antifouling properties.

[0022] (2) The preparation method of the composite organic gel lubricating coating provided by the present invention provides an important reference for the development of liquid-injected organic gel lubricating coatings. The prepared composite organic gel lubricating coating shows broad application prospects in realizing the antifouling and anticorrosion functions on the surface of a ship hull. Description of the Drawings

[0023] Figure 1 is a cross-sectional scanning electron microscope image of a glass fiber filter membrane (a) and the gel coating prepared in Comparative Example 1 (b);

[0024] Figure 2 is a cross-sectional scanning electron microscope image of the composite organic gel lubricating coating prepared in Example 1;

[0025] Figure 3 is a schematic diagram of the water contact angle test of the composite organic gel lubricating coating prepared in Example 1;

[0026] Figure 4 is a tensile test result graph of a glass fiber filter membrane, the gel coating prepared in Comparative Example 1, and the composite organic gel lubricating coating prepared in Example 1;

[0027] Figure 5 is a result graph of the coverage rate (a) and antibacterial rate (b) of Escherichia coli and Staphylococcus aureus on different glass slides in Example 2;

[0028] Figure 6 is a result graph of the coverage rate of Phaeodactylum tricornutum on different glass slides in Example 3;

[0029] Figure 7 is a fluorescence microscope image of Phaeodactylum tricornutum on different glass slides in Example 3;

[0030] Figure 8Test results of the anti-corrosion performance of gel coatings with different ratios of polyvinyl alcohol and tannic acid in Example 4, where (a) is the Tafer polarization curve; (b) is the EIS impedance diagram; (c) is the fitting result diagram of corrosion current density and corrosion potential; (d) is the test curve of the Nyquist diagram.

[0031] Figure 9 Test results of the anti-corrosion performance of different composite organic gel lubricating coatings in Example 8, where (a) is the Tafer polarization curve; (b) is the EIS impedance diagram; (c) is the fitting result diagram of corrosion current density and corrosion potential; (d) is the test curve of the Nyquist diagram.

[0032] Figure 10 Comparison results of the anti-corrosion performance of OG / PTA-3, PTA-4 and Q235 stainless steel materials in Example 8, where (a) is the Tafer polarization curve; (b) is the fitting result diagram of corrosion current density and corrosion potential. Detailed implementation manners

[0033] The present invention will be further described and illustrated below in conjunction with the accompanying drawings and specific implementation manners. The technical features of each implementation manner in the present invention can be combined correspondingly without conflict.

[0034] Example 1

[0035] This example provides a method for preparing a composite organic gel lubricating coating, and the specific steps are as follows:

[0036] I. Preparation of hydrogel (PTA) casting solution

[0037] Add 3 g of polyvinyl alcohol and 4 g of tannic acid to 100 mL of a mixed solution of ethanol and water (1:1), and heat to 95 °C until completely dissolved to obtain a hydrogel casting solution.

[0038] II. Preparation of gel coating

[0039] Immerse a clean glass fiber filter membrane (GF) into the above hydrogel casting solution, and then transfer it to a cryogenic refrigerator at -80 °C to fix the copolymer. Then place it in an oven for thermal cross-linking treatment, set the oven temperature to 60 °C, and the reaction time is 0.5 h until the water is completely evaporated to obtain a gel coating with strong adhesion. After swelling the gel coating in an aqueous solution for 5 minutes, place it in a cryogenic refrigerator for standby.

[0040] III. Preparation of organic gel (OG) casting solution

[0041] In a pre-cooled petri dish, 60 mg of vinyl-terminated polydimethylsiloxane (V-PDMS) silicone oil, 100 mg of polymethylhydrosiloxane (PHMS) crosslinker, and 15 mg of vinyltrimethoxysilane (VTMS) monomer were successively added. The mixture was stirred evenly with a glass rod, and then 1 mg of platinum catalyst was added to promote the addition reaction of the organogel, obtaining an organogel casting solution, which was used within 30 minutes.

[0042] IV. Preparation of a composite organogel lubricating coating

[0043] The above-mentioned organogel casting solution was evenly coated on the surface of the gel coating. The coated composite coating was vertically suspended. After removing the excess organogel casting solution, it was placed in an oven for curing. The oven temperature was set at 40 °C and the time was 12 h. Finally, polydimethylsiloxane (PDMS) lubricant was injected onto the surface of the cured coating, and the excess lubricant was removed, obtaining the composite organogel lubricating coating GF-OG / PTA.

[0044] Comparative Example 1

[0045] This comparative example provides a coating coated only with a hydrogel casting solution, specifically as follows:

[0046] I. Preparation of a hydrogel (PTA) casting solution

[0047] 3 g of polyvinyl alcohol and 4 g of tannic acid were added to a 100 mL mixed solution of ethanol and water (1:1). After heating to complete dissolution at 95 °C, a hydrogel casting solution was obtained.

[0048] II. Preparation of a gel coating

[0049] A clean glass fiber filter membrane GF was immersed in the above-mentioned hydrogel casting solution, and then transferred to an ultra-low temperature refrigerator at -80 °C to fix the copolymer. Subsequently, it was placed in an oven for thermal cross-linking treatment. The oven temperature was set at 60 °C and the reaction time was 0.5 h until the water was completely evaporated, obtaining the gel coating GF-PTA.

[0050] Next, the following performance tests were carried out on the composite organogel lubricating coating GF-OG / PTA prepared in Example 1 and the gel coating GF-PTA prepared in Comparative Example 1:

[0051] (1) The surface structural changes of the glass fiber filter membrane GF, the gel coating GF-PTA prepared in Comparative Example 1, and the organogel lubricating coating GF-OG / PTA prepared in Example 1 were observed by scanning electron microscopy (SEM, Sigma 360, ZEISS, Germany). The results are as Figure 1 and Figure 2As shown in the figure. Among them, the glass fiber filter membrane used as the substrate is a filter membrane that can be purchased on the market and is relatively common.

[0052] As Figure 1 shown in (a) of [reference], the glass fiber filter membrane GF exhibits a multi-fiber winding structure and the structure is relatively loose. Therefore, its tensile properties may not be good, and this result is consistent with the tensile test results described later. As Figure 1 shown in (b) of [reference], through the regulation of the hydrogen bond polymerization process, polyvinyl alcohol and tannic acid can be coated on the glass fiber, showing a layered structure. This may be attributed to the formation of strong hydrogen bonds between polyvinyl alcohol and tannic acid, endowing the gel coating with strong adhesiveness. The appearance of the fault may affect the long-term use of the coating.

[0053] Figure 2 It is a cross-sectional scanning electron micrograph of the composite organic gel lubricating coating GF-OG / PTA prepared in Example 1. As shown in the figure, its cross-section also presents a dense surface structure, and the coating thickness is about 45 μm, proving that both the hydrogel and the organic gel coating are uniformly coated on the surface of the substrate.

[0054] (2)The water contact angle (WCA) of the membrane was measured using a contact angle meter (Powereach JC2000 D1), and the results are as Figure 3 shown. According to the results, it can be seen that the composite organic gel lubricating coating GF-OG / PTA prepared in Example 1 has excellent hydrophobicity.

[0055] (3)The mechanical properties of the glass fiber filter membrane GF, the gel coating GF-PTA prepared in Comparative Example 1, and the composite organic gel lubricating coating GF-OG / PTA prepared in Example 1 were respectively tested using a tensile testing machine (Instron5944, USA), and the results are as Figure 4 shown. The results show that the tensile properties of the material coated with the composite organic gel lubricating coating have been significantly improved, reaching three times that of the original glass fiber filter membrane, confirming the practical application potential of the composite organic gel lubricating coating.

[0056] (4)The composite organic gel lubricating coating GF-OG / PTA prepared in Example 1 and the glass fiber filter membrane GF were respectively immersed in an aqueous solution stained with methylene blue to test their water resistance, and a digital video camera was used to take pictures. The results show that when the glass fiber filter membrane GF was lifted, the surface of the membrane was quickly adhered, and the composite organic gel lubricating coating made the surface of the membrane free of any water stains. Therefore, it is proved that the composite organic gel lubricating coating prepared in Example 1 has excellent hydrophobicity and water resistance.

[0057] Example 2

[0058] In this example, the antibacterial properties of the coating against Escherichia coli and Staphylococcus aureus were evaluated using the LB agar plate method as follows:

[0059] I. Preparation of hydrogel (PTA) casting solution

[0060] Add 3 g of polyvinyl alcohol and 4 g of tannic acid to a 100 mL mixed solution of ethanol and water (1:1), and heat it to 95 °C until completely dissolved to obtain the hydrogel casting solution.

[0061] II. Preparation of organogel (OG) casting solution

[0062] Sequentially add 60 mg of vinyl-terminated polydimethylsiloxane (V-PDMS) silicone oil, 100 mg of polymethylhydrosiloxane (PHMS) crosslinker, and 15 mg of vinyltrimethoxysilane (VTMS) monomer to a pre-cooled petri dish. Use a glass rod to uniformly stir the mixture, and then add 1 mg of platinum catalyst to promote the addition reaction of the organogel to obtain the organogel casting solution, and use it within 30 minutes.

[0063] III. Preparation of materials coated with hydrogel (PTA) casting solution, organogel (OG) casting solution, and composite organogel lubricating coating (OG / PTA) respectively

[0064] (1) Immerse a clean glass slide in the above hydrogel casting solution, and then transfer it to a -80 °C ultra-low temperature freezer to fix the copolymer. Subsequently, place it in an oven for thermal cross-linking treatment. The oven temperature is set at 60 °C, and the reaction time is 0.5 h until the water is completely evaporated to obtain a glass slide coated only with hydrogel.

[0065] (2) Immerse a clean glass slide in the above organogel casting solution, hang the coated OG coating vertically, remove the excess organogel casting solution, and then place it in an oven for curing. The oven temperature is set at 40 °C for 12 h. Finally, inject polydimethylsiloxane (PDMS) lubricant onto the surface of the self-cured coating, and remove the excess lubricant to obtain a glass slide coated only with organogel.

[0066] (3) Uniformly coat the organogel casting solution on the surface of the glass slide coated with hydrogel, hang the coated composite coating vertically, remove the excess organogel casting solution, and then place it in an oven for curing. The oven temperature is set at 40 °C for 12 h. Finally, inject polydimethylsiloxane (PDMS) lubricant onto the surface of the self-cured coating, and remove the excess lubricant to obtain a glass slide with a composite organogel lubricating coating.

[0067] (4) Prepare a concentration of approximately 10 in LB broth 8Escherichia coli and Staphylococcus aureus suspensions at CFU / mL and incubated for 24 hours.

[0068] Immerse a blank glass slide, a glass slide coated with hydrogel, a glass slide coated only with organic gel, and a glass slide coated with a composite organic gel lubricating coating into 20 mL of the above bacterial suspension respectively, and incubate in a constant temperature incubator at 37 °C for 24 h. Then take out the glass slides and gently wash them with sterile PBS buffer to remove weakly adherent bacteria. Then place the glass slides into 20 mL of sterile PBS buffer and perform sonication for 15 minutes (transfer the strongly adherent bacteria on the glass slides to the sterile PBS buffer for subsequent culture). Finally, dilute the sonicated liquid 10,000 times, spread it on LB agar, and then incubate at 37 °C for 24 hours. Observe the formation of colonies on the LB plates to evaluate the antibacterial properties of the coatings, and use Image J software to calculate the attachment rate and coverage rate. The results are as Figure 5 shown, where the blank is a blank glass slide without any coating.

[0069] As Figure 5 shown, the coverage rates of Staphylococcus aureus on the blank glass slide, the glass slide coated with hydrogel, and the glass slide coated with organic gel are 4.12%, 3.34%, and 1.99% respectively. For the glass slide with a composite organic gel lubricating coating, the coverage rate of Staphylococcus aureus is only 0.9%, and the antibacterial rate reaches 77%. Obviously, the OG / PTA coating can effectively reduce the attachment of Staphylococcus aureus.

[0070] In addition, a large number of Escherichia coli attach to the blank glass slide, indicating that Escherichia coli is relatively easy to attach to the hydrophilic silica glass plate, and its coverage rate reaches 4.67%. Therefore, the coverage rates of Escherichia coli on the blank glass slide, the glass slide coated with hydrogel, and the glass slide coated with organic gel are 4.67%, 3.25%, and 0.26% respectively, and the antibacterial rates of hydrogel and organic gel against Escherichia coli are 30.75% and 94.58% respectively. For the hydrogel, it has an adhesion ability formed by a hydrogen bond network. However, in a seawater environment, the Hofmeister effect will occur, resulting in the expulsion of the hydration water inside the hydrogel. These expelled hydration waters are between the substrate and the coating, which further causes the performance of the gel coating to decline after long-term use, and finally leads to the shedding of the coating. After the coating sheds, Escherichia coli can more easily cross the gel coating, thus showing a relatively high coverage rate of Escherichia coli. The organic gel coating shows more excellent antifouling performance (coverage rate 2.6% and antibacterial rate 94.58%). This result can be attributed to the release of lubricating factors, making it difficult for Escherichia coli to attach to the surface of the organic gel coating.

[0071] E. coli hardly attaches to the surface of the glass slide with a composite organic gel lubricating coating, and the coverage rate is only 0.12%, while the antibacterial rate reaches 97.45%. This may be attributed to the excellent lubricating performance of the coating and the release of antibacterial factors (tannic acid). This example demonstrates the effectiveness of the prepared composite organic gel lubricating coating in fouling applications.

[0072] Example 3

[0073] In this example, Phaeodactylum tricornutum was used as the model alga for a 30-day algal biofouling experiment. The experimental group used the same glass slides with a composite organic gel lubricating coating as in Example 2 and glass slides coated only with organic gel, and the blank group was uncoated glass slides. Figure 6 Figure showing the comparison of the coverage rates of Phaeodactylum tricornutum on different glass slides after 30 days of cultivation. The coverage rates of Phaeodactylum tricornutum on the blank glass slide and the glass slide coated only with organic gel were 8.04% and 0.84% respectively, while the coverage rate on the glass slide with a composite organic gel lubricating coating was only 0.18%. This shows that the composite organic gel lubricating coating provided by the present invention exhibits excellent ability in preventing algal biofouling.

[0074] Figure 7 Fluorescence microscope images of Phaeodactylum tricornutum on different glass slides recorded using a fluorescence biological microscope (CX40-RFL, Ningbo Sunny Instruments CO., LTD.). It can be clearly seen from the fluorescence microscope that there is no obvious red fluorescence on the composite organic gel lubricating coating, demonstrating its excellent ability to prevent algal bioattachment. However, with the increase of the cultivation time, Phaeodactylum tricornutum gradually attaches to the surface of the blank group. This result further proves that the composite organic gel lubricating coating provided by the present invention has excellent antifouling characteristics and the effectiveness of multiple antifouling strategies.

[0075] Example 4

[0076] This example provides a method for preparing a composite organic gel lubricating coating, and the specific steps are as follows:

[0077] I. Optimize the ratio of polyvinyl alcohol and tannic acid in the hydrogel casting solution

[0078] (1) Respectively add 3 g of polyvinyl alcohol and 1, 2, 3, and 4 g of tannic acid into 100 mL of a mixed solution of ethanol and water (1:1), and heat to 95 °C until completely dissolved to obtain four groups of hydrogel casting solutions with different ratios.

[0079] (2) Immerse the clean Q235 stainless steel material into the above hydrogel casting solution respectively, and then transfer it to an ultra-low temperature refrigerator at -80 °C to fix the copolymer. Subsequently, place it in an oven for thermal cross-linking treatment. The oven temperature is set at 60 °C, and the reaction time is 0.5 h until the water is completely evaporated, obtaining different gel coatings, denoted as PTA-1, PTA-2, PTA-3, and PTA-4 respectively.

[0080] (3) Use an electrochemical workstation to explore the anti-corrosion performance of PTA-1, PTA-2, PTA-3, and PTA-4. The blank sample (Q235 stainless steel material) is used as a control, and the specific steps are as follows: The EIS impedance and Tafer curve tests are carried out in a 3.5% NaCl salt solution, using the common three-electrode setup. Among them, the working electrode is connected to the sample, the reference electrode is connected to the saturated calomel electrode, and the platinum sheet is used as the counter electrode. In addition, the corrosion potential and corrosion current density are calculated through the Tafer curve. The results are as Figure 8 shown.

[0081] According to Figure 8 in (a) and Figure 8 in (b), it can be clearly observed that compared with the blank sample, the corrosion potential of the gel coating increases. This may be due to the fact that the gel coating has a large number of hydrophilic functional groups, resulting in water being easily in contact with the substrate. However, the corrosion current density decreases significantly. This may be because the gel coating forms a dense protective layer through a closer reaction with the Q235 stainless steel material, effectively preventing further corrosion. According to Figure 8 in (c) and Figure 8 in (d), it can be seen from the EIS and Nyquist plot results of the gel coating that when the ratio of polyvinyl alcohol to tannic acid is 3:4, the anti-corrosion performance is the best. Therefore, this ratio is used in subsequent experiments.

[0082] II. Preparation of hydrogel (PTA) casting solution

[0083] Add 3 g of polyvinyl alcohol and 4 g of tannic acid to a 100 mL mixed solution of ethanol and water (1:1), and heat it to 95 °C until completely dissolved to obtain the hydrogel casting solution.

[0084] II. Preparation of gel coating

[0085] Immerse the clean Q235 stainless steel material into the above hydrogel casting solution, and then transfer it to an ultra-low temperature refrigerator at -80 °C to fix the copolymer. Subsequently, place it in an oven for thermal cross-linking treatment. The oven temperature is set at 60 °C, and the reaction time is 0.5 h until the water is completely evaporated to obtain a gel coating with strong adhesion. After the gel coating is swollen in an aqueous solution for 5 minutes, place it in an ultra-low temperature refrigerator for standby.

[0086] III. Preparation of Organic Gel (OG) Casting Solution

[0087] In a pre-cooled petri dish, sequentially add 60 mg of vinyl-terminated polydimethylsiloxane (V-PDMS) silicone oil, 100 mg of polymethylhydrosiloxane (PHMS) crosslinker, and 5 mg of vinyltrimethoxysilane (VTMS) monomer. Use a glass rod to uniformly stir the mixture, and then add 1 mg of platinum catalyst to promote the addition reaction of the organic gel, obtaining the organic gel casting solution, which is to be used within 30 minutes.

[0088] IV. Preparation of Composite Organic Gel Lubricating Coating

[0089] Uniformly coat the above-mentioned organic gel casting solution on the surface of the gel coating. Hang the coated composite coating vertically. After removing the excess organic gel casting solution, place it in an oven for curing. The oven temperature is set at 40 °C for 12 h. Finally, inject polydimethylsiloxane (PDMS) lubricant onto the surface of the cured coating, and remove the excess lubricant to obtain the composite organic gel lubricating coating denoted as OG / PTA-1.

[0090] Example 5

[0091] Compared with Example 4, this example also provides a method for preparing a composite organic gel lubricating coating. In the process of preparing the organic gel (OG) casting solution in this example, sequentially add 60 mg of vinyl-terminated polydimethylsiloxane (V-PDMS) silicone oil, 100 mg of polymethylhydrosiloxane (PHMS) crosslinker, and 10 mg of vinyltrimethoxysilane (VTMS) monomer in a pre-cooled petri dish. Use a glass rod to uniformly stir the mixture, and then add 1 mg of platinum catalyst to promote the addition reaction of the organic gel, obtaining the organic gel casting solution, which is to be used within 30 minutes. The remaining steps are the same as those in Example 4, and the obtained composite organic gel lubricating coating is denoted as OG / PTA-2.

[0092] Example 6

[0093] Compared with Example 4, this example also provides a method for preparing a composite organic gel lubricating coating. In the process of preparing the organic gel (OG) casting solution in this example, sequentially add 60 mg of vinyl-terminated polydimethylsiloxane (V-PDMS) silicone oil, 100 mg of polymethylhydrosiloxane (PHMS) crosslinker, and 15 mg of vinyltrimethoxysilane (VTMS) monomer in a pre-cooled petri dish. Use a glass rod to uniformly stir the mixture, and then add 1 mg of platinum catalyst to promote the addition reaction of the organic gel, obtaining the organic gel casting solution, which is to be used within 30 minutes. The remaining steps are the same as those in Example 4, and the obtained composite organic gel lubricating coating is denoted as OG / PTA-3.

[0094] Example 7

[0095] Compared to Example 4, this example also provides a method for preparing a composite organogel lubricating coating. In this example, to prepare the organogel (OG) casting solution, 60 mg of vinyl-terminated polydimethylsiloxane (V-PDMS) silicone oil, 100 mg of polymethylhydrogensiloxane (PHMS) crosslinker, and 20 mg of vinyltrimethoxysilane (VTMS) monomer were sequentially added to a pre-cooled Petri dish. The mixture was uniformly stirred with a glass rod, and 1 mg of platinum catalyst was added to promote the addition reaction of the organogel to obtain the organogel casting solution, which was used within 30 minutes. The remaining steps were consistent with those in Example 4, resulting in a composite organogel lubricating coating designated OG / PTA-4.

[0096] Example 8

[0097] In this example, an electrochemical workstation (Ametek Parstat 4000) was used to test the corrosion resistance of OG / PTA-1, OG / PTA-2, OG / PTA-3, OG / PTA-4 prepared in Examples 4 to 7, as well as the blank group Q235 stainless steel material. The details are as follows: EIS impedance and Tafer curve tests were carried out in a 3.5% NaCl salt solution using a common three-electrode setup, in which the working electrode was connected to the sample, the reference electrode was connected to a saturated calomel electrode, and a platinum sheet was used as the counter electrode. In addition, the corrosion potential and corrosion current density were calculated using the Tafer curve. The results are shown in Figure 2. Figure 9 shown.

[0098] according to Figure 9 (a) and Figure 9 As shown in (b), the OG / PTA-3 prepared in Example 6 has the strongest corrosion resistance in the Tafer test. This may be because the Si-OH groups of the organogel further react with the gel TA coating through the condensation of the organogel, promoting the formation of a cross-linked network, thereby forming a dense surface structure. Figure 9 As shown in (c), the OG / PTA-3 prepared in Example 6 has the best anti-corrosion performance, and its impedance value reaches about 1.8×10 5 Ω·cm 2 . Figure 9 The largest semicircle diameter in the Nyquist plot capacitance arc (d) effectively confirms the excellent corrosion resistance of OG / PTA-3 prepared in Example 6, indicating that the prepared composite organogel lubricating coating has practical application potential. However, the Nyquist plot capacitance arc diameter of OG / PTA-1 prepared in Example 4 is smaller (not visible in the figure), likely due to the relatively low addition of vinyltrimethoxysilane, resulting in relatively poor adhesion of the organogel coating to the gel coating surface.

[0099] Figure 10 Comparison of the anti-corrosion properties of OG / PTA-3 prepared in Example 6, PTA-4 coated only with a gel coating in Example 4, and Q235 stainless steel material. According to Figure 10 in (a) and Figure 10 in (b), it can be seen that compared with the blank Q235 stainless steel material, the corrosion potential of PTA-4 coated with a gel coating increased slightly. Fortunately, however, the corrosion current of the material coated with the composite organic gel lubricating coating decreased. More importantly, the corrosion current of the Q235 stainless steel material was 10 -3.365 A / cm 2 , and after applying the composite organic gel lubricating coating, the corrosion current of the material decreased to about 10 -6.3987 A / cm 2 , improving the anti-corrosion ability by three orders of magnitude, further demonstrating that the composite organic gel lubricating coating provided by the present invention has excellent anti-corrosion performance and practical application potential.

[0100] Example 9

[0101] In this example, actual corrosion tests were carried out in the ocean of Zhoushan Sea area, as follows:

[0102] PTA-4 coated only with a gel coating in Example 4 (Q235 stainless steel material coated with a gel coating), OG / PTA-3 prepared in Example 6 (Q235 stainless steel material coated with a composite organic gel lubricating coating), stainless steel material coated with lubricant PDMS, and blank stainless steel material were respectively placed in seawater. During high tide, the coating was immersed, and during low tide, the coating was exposed (at the three-phase interface of seawater / air / coating, the coating was more likely to corrode). A digital video camera was used to record the corrosion situation during the 15-day test. It can be clearly observed that there was no obvious corrosion on the surface coated with the composite organic gel lubricating coating, which benefited from the anti-corrosion ability conferred by the excellent hydrophobic properties of the coating. This result was consistent with the above electrochemical results, further demonstrating the practical application potential of the composite organic gel coating provided by the present invention.

[0103] The above-described embodiments are only a preferred solution of the present invention, but they are not intended to limit the present invention. Those of ordinary skill in the relevant technical field can still make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all technical solutions obtained by adopting equivalent replacement or equivalent transformation fall within the protection scope of the present invention.

Claims

1. A preparation method of a composite organic gel lubricating coating, characterized in that, The specific steps are as follows: S1: Add polyvinyl alcohol and tannic acid to an ethanol solution and heat until completely dissolved to obtain a hydrogel casting solution; immerse a clean substrate in the hydrogel casting solution, remove it, cool it, and then perform a thermal cross-linking treatment until the water is completely evaporated to obtain a gel coating; S2: mixing a vinyl-containing siloxane monomer, a vinyl-containing silicone oil, and a silane crosslinker containing a hydrogen-silicon bond, and adding a platinum catalyst to promote the addition reaction to prepare an organogel casting solution; S3: evenly coating the organogel casting solution obtained in step S2 on the surface of the gel coating obtained in step S1, removing excess organogel casting solution and then curing; injecting lubricating liquid into the surface of the self-cured coating and removing excess lubricating liquid to obtain a composite organic gel lubricating coating; In step S1, the mass ratio of polyvinyl alcohol to tannic acid is 3:(1-4); In step S2, the vinyl-containing siloxane monomer is vinyltrimethoxysilane; the vinyl-containing silicone oil is vinyl-terminated polydimethylsiloxane; the silane crosslinker containing hydrogen-silicon bonds is polymethylhydrogensiloxane; and the mass ratio of the vinyl-terminated polydimethylsiloxane, polymethylhydrogensiloxane and vinyltrimethoxysilane is 12:20:(1~4).

2. The preparation method of the composite organic gel lubricating coating according to claim 1, characterized in that, The volume ratio of ethanol to water in the ethanol solution in step S1 is (4-6): (6-4).

3. The preparation method of the composite organic gel lubricating coating according to claim 1, characterized in that The substrate stained with the hydrogel casting solution in step S1 is placed in an ultra-low temperature refrigerator at -80°C for cooling and fixing.

4. The method for preparing the composite organic gel lubricating coating according to claim 1, characterized in that, The thermal cross-linking treatment in step S1 is carried out in an oven at a temperature of 40-80° C. for a time of 0.5-1 h.

5. The preparation method of the composite organic gel lubricating coating according to claim 1, wherein The ratio of the added amount of the platinum catalyst to the polymethylhydrogensiloxane is 1: (80-120).

6. The preparation method of the composite organic gel lubricating coating according to claim 1, characterized in that The curing in step S3 is performed in an oven at a temperature of 25-40° C. for 12-24 h.

7. The preparation method of the composite organic gel lubricating coating according to claim 1, wherein The lubricating fluid in step S3 is polydimethylsiloxane, perfluoropolyether or silicone oil.

8. A composite organic gel lubricating coating prepared according to the preparation method according to any one of claims 1 to 7.

9. Use of the composite organic gel lubricating coating according to claim 8 in marine antifouling and anticorrosion, characterized in that, The composite organic gel lubricating coating is used for antifouling and anticorrosion on the surface of a ship hull.

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