Method for preparing durable underwater super-oleophobic coating with dynamic self-healing capacity through one-step method as well as product and application of durable underwater super-oleophobic coating

Abstract

The invention belongs to the technical field of functional coatings, and particularly relates to a method for preparing a durable underwater super-oleophobic coating with dynamic self-healing capacity through a one-step method as well as a product and application of the durable underwater super-oleophobic coating. According to the method disclosed by the invention, a one-step method is adopted, molecules with complex structures are directly obtained from relatively simple and easily available raw materials without separation of intermediates, and the method is relatively beneficial in economy and environmental friendliness. In addition, according to the method provided by the invention, the mechanical property, the adhesion property, the severe environment resistance, the oil-water separation property and the self-cleaning property of the coating are enhanced. The method and the product provided by the invention have wide application prospects.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of functional coating, and particularly relates to a method for preparing a durable underwater superoleophobic coating with dynamic self-healing ability by one-step method, and products and applications thereof. BACKGROUND

[0002] Underwater superoleophobic coating has a wide application prospect in many fields such as marine facility maintenance, environmental protection, anti-bioadhesion, liquid treatment and oil-water separation due to its excellent oil stain resistance. Among them, the hydrophilic polymer can effectively resist the adhesion of organic pollutants and microorganisms due to the rich hydrophilic groups, thereby having good underwater antifouling performance. However, the adhesion between the material and the substrate is weakened due to the water absorption and swelling of the material during use, thereby affecting the mechanical durability. In addition, the wettability of the superhydrophilic surface structure may change when it is physically or chemically damaged; and the introduction of a self-repairing dynamic reversible structure can restore the surface performance, but may sacrifice the internal stability and mechanical strength of the material. Therefore, it is still a major challenge to develop underwater anti-adhesion materials with excellent mechanical properties and self-repairing ability to significantly improve the surface durability. Unfortunately, due to the shortcomings of material design and construction method, there are few reports on underwater superoleophobic coatings integrating multiple functions.

[0003] Based on the above background, it is of great scientific research value and practical significance to develop a multifunctional underwater superoleophobic coating with strong adhesion strength, excellent self-repairing ability, efficient oil-water separation ability and self-cleaning performance, which is expected to play an important role in many application fields.

[0004] Therefore, the present application is proposed. SUMMARY

[0005] The present application provides a preparation method for preparing a durable underwater superoleophobic coating with dynamic self-healing ability by one-step method. The method solves the problems of complex preparation process and poor water resistance of the hydrophilic coating, and simultaneously enhances the mechanical properties and self-repairing properties of the coating.

[0006] The technical scheme provided by the present application is as follows:

[0007] In a first aspect, the present application provides a method for preparing a durable underwater superoleophobic coating with dynamic self-healing ability, comprising the following steps: using IPDI, PTMEG, DBTDL and substance A as raw materials to prepare a prepolymer containing an adhesive group; adding a hydrophilic chain extender, a self-repairing chain extender, DMAC, triethylamine and deionized water in sequence to prepare a waterborne polyurethane LWPU dispersion with self-repairing function; using the waterborne polyurethane LWPU dispersion with self-repairing function, substance B and substance C as raw materials to obtain a solution with hydrogen bonding domains, and forming a coating after coating; wherein substance A is selected from E44 or E51; substance B is selected from PVA or SA; and substance C is selected from HEC or HPMC.

[0008] Preferably, IPDI, PTMEG, DBTDL and substance A are used as raw materials, and the reaction is carried out at 80±5℃ for 3±0.5h under N2 atmosphere to form a prepolymer containing an adhesive group.

[0009] Preferably, the hydrophilic chain extender is selected from DMPA.

[0010] Preferably, the self-repairing chain extender is selected from LA.

[0011] Preferably, after the prepolymer containing an adhesive group is prepared, the hydrophilic chain extender DMPA is added to improve the water solubility and dispersibility of the polyurethane; then the temperature of the reaction system is raised to 90±5℃, the self-repairing chain extender is added for continuous reaction for 15±3h, and the system viscosity is adjusted by adding DMAC; triethylamine is added for reaction for 15±3min to neutralize the carboxyl group; and deionized water is added to fully disperse the prepolymer.

[0012] Preferably, substance B is a PVA solution with a mass fraction of 1%±0.5% or a SA solution with a mass fraction of 1%±0.5%.

[0013] Preferably, substance C is a HEC solution with a mass fraction of 1%±0.5% or a HPMC solution with a mass fraction of 1%±0.5%.

[0014] Preferably, the solid content of the waterborne polyurethane LWPU dispersion with self-repairing function is 13%±1%.

[0015] Preferably, the waterborne polyurethane LWPU dispersion with self-repairing function, substance B and substance C are used as raw materials, and mixed and stirred at 50±5℃ for 2±0.5h to form hydrogen bonding domains, to prepare a PHLWPU solution; wherein the volume ratio of the waterborne polyurethane LWPU dispersion with self-repairing function, substance B and substance C is 2±0.1:1±0.1:1±0.1.

[0016] In a second aspect, the present application provides a durable underwater superoleophobic coating with dynamic self-healing ability prepared by the method of the first aspect.

[0017] In a third aspect, the present application provides the use of the method of the first aspect or the durable underwater superoleophobic coating with dynamic self-healing ability of the second aspect in the field of oil-proofing.

[0018] Exemplarily, the present application provides an oil-proofing method, which uses the method of the first aspect to prepare an oil-proofing coating on the surface of a product to be protected, thereby achieving the effect of efficient oil-proofing.

[0019] Advantages:

[0020] The present application provides a method for preparing a durable underwater superoleophobic coating with dynamic self-healing ability in one step, as well as products and applications thereof. The method comprises the following steps: using IPDI, PTMEG, DBTDL and substance A as reaction raw materials to prepare a prepolymer containing an adhesion group; sequentially adding a hydrophilic chain extender, a self-repairing chain extender, DMAC, triethylamine and deionized water in steps to prepare a waterborne polyurethane LWPU dispersion with self-repairing function; using the waterborne polyurethane LWPU dispersion with self-repairing function, substance B and substance C as reaction raw materials to obtain a solution with hydrogen bonding domains (named PHLWPU in the examples), which forms a coating after coating; wherein substance A is selected from E44 or E51; substance B is selected from PVA or SA; and substance C is selected from HEC or HPMC. The method provided by the present application uses a "one-step method", starting from relatively simple and readily available raw materials, without separation of intermediates, directly obtaining complex molecules, which is more advantageous in economy and environmental friendliness. In addition, the method provided by the present application also enhances the mechanical properties, adhesion properties, harsh environment resistance, oil-water separation and self-cleaning properties of the coating. The method and products provided by the present application have broad application prospects. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present application or prior art, the following will describe the drawings needed to be used in the embodiments or prior art description.

[0022] Figure 1 Water contact angle change of PHLWPU coating and corresponding underwater oil contact angle.

[0023] Figure 2 Load-bearing demonstration of PHLWPU coating.

[0024] Figure 3 Chemical durability of PHLWPU coating.

[0025] Figure 4 Stress-strain curve of PHLWPU coating under different volume ratios.

[0026] Figure 5Self-cleaning performance of PHLWPU coating.

[0027] Figure 6 Oil-water separation performance of PHLWPU coating.

[0028] Figure 7 Self-repairing performance of PHLWPU coating. DETAILED DESCRIPTION

[0029] The present application aims to provide a preparation method for preparing a durable underwater super-oleophobic coating with dynamic self-repairing ability by using a "one-step method".

[0030] To solve the problems in the background art, the preparation method first modifies the polyurethane with lipoic acid, and then forms hydrogen bonds between the lipoic acid-modified polyurethane, polyvinyl alcohol (or sodium alginate) and hydroxypropyl methylcellulose (or hydroxyethyl cellulose) to improve the surface mechanical durability. The coating preparation uses a "one-step method", starting from relatively simple and readily available raw materials, without the separation of intermediates, directly obtaining complex molecules, which is more economically and environmentally friendly. The problem of complex and harsh coating preparation process is solved.

[0031] As an example, in one of the more specific and preferred embodiments provided by the present application, the method for preparing a durable underwater super-oleophobic coating with dynamic self-repairing ability by using a "one-step method" includes the following steps:

[0032] Step one, preparation of lipoic acid-modified polyurethane.

[0033] IPDI, PTMEG, E44 and DBTDL were added to a three-necked flask and reacted at 80°C under N2 atmosphere for 3 h to form a prepolymer containing adhesion groups. After the reaction was completed, the hydrophilic chain extender DMPA was added to improve the water solubility and dispersibility of the polyurethane. Then, the temperature of the reaction system was raised to 90°C. The self-repairing chain extender LA was added to the reaction system and continued to react for 15 h, and an appropriate amount of DMAC was added in the above step according to the viscosity of the system. Finally, triethylamine TEA was slowly added and stirred for 15 min to neutralize the carboxyl group. Then, deionized water was quickly added and stirred at 1600 rpm for 30 min to fully disperse the prepolymer, obtaining a waterborne polyurethane LWPU dispersion with self-repairing function.

[0034] Step two, preparation of a durable underwater super-oleophobic coating with dynamic self-repairing ability.

[0035] First, hydroxypropyl methylcellulose HPMC was added into 50 mL deionized water at 80℃ and stirred for 30 min, then added into 50 mL deionized water at room temperature and stirred for 1 h to prepare a solution with a mass fraction of 1%. Second, polyvinyl alcohol PVA was added into 100 mL deionized water at 90℃ and stirred for 30 min to prepare a polyvinyl alcohol solution with a mass fraction of 1%. Finally, an appropriate amount of LWPU, PVA and HPMC solution was mixed and stirred at 50℃ for 2 h to form a hydrogen bond domain. Then, an appropriate amount of PHLWPU solution was coated on a glass sheet and placed on an 80℃ heating table for curing for 6 h to obtain a PHLWPU super-hydrophilic composite coating.

[0036] Hydrophilic polymers can effectively prevent the adhesion of organic pollutants and microorganisms due to their containing a large number of hydrophilic groups, and exhibit excellent underwater anti-adhesion performance, and are widely used in the fields of drag reduction, biomedical, flexible electronics and antifouling materials. However, due to the water absorption and swelling of the polymer, the interfacial force between the polymer and the substrate is weakened, and the high hydrophilicity of the hydrophilic polymer brings significant challenges to the adhesion of the substrate and the mechanical properties of itself. The above-mentioned method provided by the present application adds lipoic acid and epoxy modified polyurethane, and the reaction between the epoxy resin with a rigid aromatic structure and the polyurethane segment increases the crosslinking density inside the LWPU material, thereby enhancing the cohesive strength. In addition, the epoxy ring of E44 can form new carbon-oxygen covalent bonds and hydrogen bonds with the hydroxyl groups on the surface of the substrate to increase the interaction with the substrate, further improving the adhesion performance and durability of the underwater super-oleophobic coating; secondly, the present application uses a one-step crosslinking method to combine the hydrophilic polymer segment into the polymer chain, and the introduction of the hydrophilic branched structure into the molecular chain of the polymer material by the hydrogen bond crosslinking method is an ideal choice to solve the poor compatibility of hydrophilic and adhesive, which affects the overall effect. The present application is prepared by using "one-step method", which improves the shortcoming of easy falling off of traditional hydrophilic coating. In addition, due to the breaking and rebuilding of dynamic disulfide bonds and hydrogen bonds, the present application exhibits good self-repairing performance underwater.

[0037] The present application provides a method for preparing a durable underwater super-oleophobic coating with dynamic self-healing ability by using "one-step method", as well as products and applications thereof.

[0038] The present application will be described below with reference to specific examples, and it should be noted that these examples are merely descriptive and do not limit the present application in any way. Based on the examples in the present application, all other examples obtained by those of ordinary skill in the art without creative labor are within the scope of protection of the present application.

[0039] The endpoints of the ranges and any values disclosed in this specification are not limited to the precise values recited as the exact dimensions are not considered critical for the practice of the application. Attributable to the ranges of numerical values, the endpoints of the ranges, the endpoints of the ranges and individual points between the endpoints of the ranges, and individual points between the endpoints of the ranges can be combined with one another to create one or more new ranges of values not expressly recited in this specification. Such ranges of values are considered to be within the scope of the present disclosure.

[0040] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", or "some specific embodiments" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the different embodiments or examples described in the present specification and the features of the different embodiments or examples can be combined and combined by those skilled in the art without contradiction.

[0041] The materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained from commercial sources. The experimental methods in the examples not specified, are generally carried out according to the conventional conditions, or according to the conditions recommended by the manufacturer.

[0042] In the following examples, the source information of each raw material is as follows:

[0043] IPDI, Shanghai Aladdin Bio-Chem Technology Co., Ltd., I109582.

[0044] PTMEG, Shanghai Jizhi Biochemical Co., Ltd., P57070.

[0045] E44, SINOPEC Baling Petrochemical Co., Ltd., T-2167.

[0046] E51, SINOPEC Baling Petrochemical Co., Ltd., T-9402.

[0047] DBTDL, Shanghai Aladdin Bio-Chem Technology Co., Ltd., D100274.

[0048] DMPA, Shanghai Aladdin Bio-Chem Technology Co., Ltd., B104539.

[0049] LA, Shanghai Aladdin Bio-Chem Technology Co., Ltd., T106640.

[0050] DMAC, Shanghai Aladdin Bio-Chem Technology Co., Ltd., D108096.

[0051] TEA, Shanghai Aladdin Bio-Chem Technology Co., Ltd., T103285.

[0052] HPMC, Shanghai Aladdin Bio-Chem Technology Co., Ltd., H108827.

[0053] HEC, Shanghai Aladdin Bio-Chem Technology Co., Ltd., H104794.

[0054] PVA, Shanghai Aladdin Bio-Chem Technology Co., Ltd., P105126.

[0055] SA, Shanghai Aladdin Bio-Chem Technology Co., Ltd., S1506463.

[0056] Example 1

[0057] This example provides a method for preparing a durable underwater super-oleophobic coating with dynamic self-healing ability by using a one-step method.

[0058] First, 3.42 g of IPDI, 8.00 g of PTMEG, 0.91 g of E44, and 5 μL of DBTDL were added to a three-necked flask and reacted at 80°C for 3 h under N2 atmosphere to form a prepolymer containing adhesion groups. After the reaction was completed, 0.80 g of DMPA, a hydrophilic chain extender, was added to improve the water solubility and dispersibility of the polyurethane. Subsequently, the temperature of the reaction system was raised to 90°C. 0.52 g of LA, a self-repairing chain extender, was added to the reaction system for continued reaction for 15 h, and 10-20 mL of DMAC was added in the above step according to the viscosity of the system. Finally, 0.90 g of TEA was slowly added and stirred for 15 min to neutralize the carboxyl group. Then, deionized water was quickly added, and stirred at 1600 rpm for 30 min to fully disperse the prepolymer, obtaining a waterborne polyurethane LWPU dispersion with self-repairing function. Second, 1.0 g of HPMC was added to 50 mL of deionized water at 80°C and stirred for 30 min, and then 50 mL of deionized water was added and stirred at room temperature for 1 h to prepare a solution with a mass fraction of 1 %. 1.0 g of PVA was added to 100 mL of deionized water at 90°C and stirred for 30 min to prepare a polyvinyl alcohol solution with a mass fraction of 1 %. Finally, 20 mL of LWPU, 10 mL of PVA, and 10 mL of HPMC solution were mixed at 50°C and stirred for 2 h to form a hydrogen bonding domain. Then, an appropriate amount of PHLWPU solution was coated on a glass sheet and placed on a heating table at 80°C for curing for 6 h to obtain a PHLWPU super-hydrophilic composite coating.

[0059] Example 2

[0060] The present embodiment provides a durable underwater super-oleophobic coating with dynamic self-healing ability prepared by a "one-step method".

[0061] First, 3.42 g IPDI, 8.00 g PTMEG, 0.91 g E44 and 5 μL DBTDL were added into a three-necked flask and reacted at 80℃ for 3 h under N2 atmosphere to form a prepolymer containing adhesion groups. After the reaction was completed, 0.80 g DMPA, a hydrophilic chain extender, was added to improve the water solubility and dispersibility of the polyurethane. Subsequently, the temperature of the reaction system was raised to 90℃. 0.52 g LA, a self-repairing chain extender, was added to the reaction system for further reaction for 15 h, and 10-20 mL DMAC was added in the above step according to the viscosity of the system. Finally, 0.90 g TEA, triethylamine, was slowly added and stirred for 15 min to neutralize the carboxyl group. Then, deionized water was quickly added, and stirred at 1600 rpm for 30 min to fully disperse the prepolymer, obtaining a waterborne polyurethane LWPU dispersion with self-repairing function. Second, 1.0 g HPMC, hydroxypropyl methyl cellulose, was added into 50 mL deionized water at 80℃ and stirred for 30 min, and then 50 mL deionized water was added and stirred at room temperature for 1 h to prepare a solution with a mass fraction of 1 %. 1.0 g PVA, polyvinyl alcohol, was added into 100 mL deionized water at 90℃ and stirred for 30 min to prepare a polyvinyl alcohol solution with a mass fraction of 1 %. Finally, an appropriate amount of the LWPU, PVA and HPMC solutions with different proportions were mixed and stirred at 50℃ for 2 h to form a hydrogen bonding domain. Then, an appropriate amount of the PHLWPU solution was coated on a glass sheet and placed on a heating table at 80℃ for curing for 6 h to obtain a PHLWPU super-hydrophilic composite coating. The amounts of the waterborne polyurethane LWPU dispersion with self-repairing function, substance B and substance C with different proportions are shown in Table 1.

[0062] Table 1 Amounts of the waterborne polyurethane LWPU dispersion with self-repairing function, substance B and substance C

[0063]

[0064] Example 3

[0065] The present embodiment provides a durable underwater super-oleophobic coating with dynamic self-healing ability prepared by a "one-step method".

[0066] First, 3.42 g IPDI, 8.00 g PTMEG, 0.78 g E51 and 5 μL DBTDL were added into a three-necked flask and reacted at 80 ℃ for 3 h under N2 atmosphere to form a prepolymer containing adhesion groups. After the reaction was completed, 0.80 g DMPA, a hydrophilic chain extender, was added to improve the water solubility and dispersibility of the polyurethane. Subsequently, the temperature of the reaction system was raised to 90 ℃. 0.52 g LA, a self-repairing chain extender, was added into the reaction system for further reaction for 15 h, and 10-20 mL DMAC was added in the above step according to the viscosity of the system. Finally, 0.90 g TEA, triethylamine, was slowly added and stirred for 15 min to neutralize the carboxyl group. Then, deionized water was quickly added, and the prepolymer was fully dispersed by stirring at 1600 rpm for 30 min to obtain a waterborne polyurethane (LWPU) dispersion with self-repairing function. Second, 1.0 g HPMC (hydroxypropyl methyl cellulose) was added into 50 mL deionized water at 80 ℃ and stirred for 30 min, and then 50 mL deionized water was added and stirred at room temperature for 1 h to prepare a solution with a mass fraction of 1 %. 1.0 g PVA (polyvinyl alcohol) was added into 100 mL deionized water at 90 ℃ and stirred for 30 min to prepare a PVA solution with a mass fraction of 1 %. Finally, 20 mL LWPU, 10 mL PVA and 10 mL HPMC solution were mixed and stirred at 50 ℃ for 2 h to form a hydrogen bonding domain. Then, an appropriate amount of PHLWPU solution was coated on a glass sheet and placed on a heating table at 80 ℃ for curing for 6 h to obtain a PHLWPU superhydrophilic composite coating.

[0067] Example 4

[0068] This example provides a method for preparing a durable underwater superoleophobic coating with dynamic self-healing ability by using a one-step method.

[0069] First, 3.42 g IPDI, 8.00 g PTMEG, 0.91 g E44 and 5 μL DBTDL were added into a three-necked flask and reacted at 80 °C for 3 h under N2 atmosphere to form a prepolymer containing adhesion groups. After the reaction was completed, 0.80 g DMPA, a hydrophilic chain extender, was added to improve the water solubility and dispersibility of the polyurethane. Subsequently, the temperature of the reaction system was raised to 90 °C. 0.52 g LA, a self-repairing chain extender, was added into the reaction system for further reaction for 15 h, and 10-20 mL DMAC was added in the above step according to the viscosity of the system. Finally, 0.90 g TEA, triethylamine, was slowly added and stirred for 15 min to neutralize the carboxyl group. Then, deionized water was quickly added, and the prepolymer was fully dispersed by stirring at 1600 rpm for 30 min to obtain a waterborne polyurethane (LWPU) dispersion with self-repairing function. Second, 1.0 g HEC, hydroxyethyl cellulose, was directly dissolved in 100 mL deionized water and stirred for 3 h to prepare a 1 % solution. 1.0 g PVA, polyvinyl alcohol, was added into 100 mL deionized water at 90 °C and stirred for 30 min to prepare a 1 % polyvinyl alcohol solution. Finally, 20 mL LWPU, 10 mL PVA and 10 mL HEC solution were mixed at 50 °C and stirred for 2 h to form a hydrogen-bonding domain. Then, an appropriate amount of PHLWPU solution was coated on a glass sheet and placed on a heating table at 80 °C for curing for 6 h to obtain a PHLWPU super-hydrophilic composite coating.

[0070] Example 5

[0071] This example provides a method for preparing a durable underwater super-oleophobic coating with dynamic self-healing ability by using a one-step method.

[0072] First, 3.42 g IPDI, 8.00 g PTMEG, 0.91 g E44 and 5 μL DBTDL were added into a three-necked flask and reacted at 80 °C for 3 h under N2 atmosphere to form a prepolymer containing adhesive groups. After the reaction was completed, 0.80 g DMPA, a hydrophilic chain extender, was added to improve the water solubility and dispersibility of the polyurethane. Subsequently, the temperature of the reaction system was raised to 90 °C. 0.52 g LA, a self-repairing chain extender, was added to the reaction system for further reaction for 15 h, and 10-20 mL DMAC was added in the above steps according to the viscosity of the system. Finally, 0.90 g TEA, triethylamine, was slowly added and stirred for 15 min to neutralize the carboxyl group. Then, deionized water was quickly added, and stirred at 1600 rpm for 30 min to make the prepolymer fully dispersed, obtaining a waterborne polyurethane LWPU dispersion with self-repairing function. Second, 1.0 g HPMC, hydroxypropyl methyl cellulose, was added into 50 mL deionized water at 80 °C and stirred for 30 min, and then 50 mL deionized water was added and stirred at room temperature for 1 h to prepare a solution with a mass fraction of 1 %. 1.0 g SA, sodium alginate, was added into 100 mL deionized water at 90 °C and stirred for 30 min to prepare a sodium alginate solution with a mass fraction of 1 %. Finally, an appropriate amount of 20 mL LWPU, 10 mL SA and 10 mL HPMC solution were mixed and stirred at 50 °C for 2 h to form a hydrogen bonding domain. Then, an appropriate amount of SHLWPU solution was coated on a glass sheet and placed on an 80 °C heating table for curing for 6 h to obtain a SHLWPU superhydrophilic composite coating.

[0073] Experimental Example 1

[0074] In this experimental example, PHLWPU (Example 1) was used as the experimental material to test the wettability.

[0075] The test method for the water contact angle was to place a syringe needle filled with deionized water directly above the coating in the air at room temperature, and then release a deionized water droplet onto the surface of the coating to measure the water contact angle in the air, and observe the trend of the water contact angle over time. The test method for the underwater oil contact angle was to immerse the coating in a deionized water tank. A syringe needle filled with heavy oil was placed directly above the coating, and a heavy oil dichloromethane droplet was released onto the surface of the coating to be measured. The average volume of the oil droplet and the water droplet was 5.0 μL. All the contact angle data in this experiment were the average values of three measurements at different regions on the surface of the coating.

[0076] The experimental results are shown in Figure 1 .

[0077] Figure 1In Figure (a), a water droplet on the PHLWPU coating surface spreads from 30.22 ± 0.5° to complete its spread after 330 seconds; Figure (b) shows that the underwater oil contact angle of the PHLWPU coating is 170.15 ± 0.6°. Figure 1 It is evident that this material belongs to the category of superhydrophilic / underwater superoleophobic materials.

[0078] Experiment Example 2

[0079] This experiment uses PHLWPU (Example 1) as the experimental material to test its load-bearing effect.

[0080] The test method involves passing the coated sample through a heavy object, holding both ends by hand, and pulling it upwards to observe its state at the moment it bears a weight far exceeding its own weight and afterwards.

[0081] The experimental results are shown in Figure 2 .

[0082] Depend on Figure 2 As can be seen, a coating sample of only 0.15 g can support a weight of 2 kg, proving its excellent mechanical properties.

[0083] Experimental Example 3

[0084] This experimental example uses PHLWPU (Example 1) as the experimental material to test its chemical durability.

[0085] The test method involved immersing the coating in aqueous solution, acidic solution with pH=3, alkaline solution with pH=11, and artificial seawater, and measuring and recording the changes in contact angle and coating stability.

[0086] The experimental results are shown in Figure 3 .

[0087] Depend on Figure 3 It can be seen that after 12 hours of immersion in acid / alkali and artificial seawater solutions, the underwater oil droplet contact angle of the PHLWPU coating remained stable at over 150° and there was no peeling, proving that the coating surface has stable superhydrophilic / underwater superoleophobic properties and coating adhesion.

[0088] Experiment Example 4

[0089] This experimental example uses PHLWPU (Example 2) as the experimental material to conduct experiments on its mechanical properties.

[0090] The test method involves making the sample into a dumbbell shape and performing stress-strain tests using a universal testing machine.

[0091] The experimental results are shown in Figure 4 .

[0092] Depend on Figure 4It can be seen that compared with the LWPU material, the hydrogen bonding domain formed by PVA and HPMC significantly improves the mechanical properties of PHLWPU. However, excessive hydrogen bonding crosslinking leads to damage to the uniformity of the material, thereby reducing the internal cohesive force.

[0093] Experimental Example 5

[0094] In this experimental example, PHLWPU (Example 3) is used as the experimental material to experiment on the self-cleaning performance.

[0095] The test method is to shake the coating contaminated by crude oil in water, and observe the situation of crude oil falling off the surface of the coating.

[0096] The experimental results are shown in Figure 5 .

[0097] As can be seen from Figure 5 , after the PHLWPU coating surface pre-wetted by water is dripped with crude oil and then immersed in water and shaken gently, it is found that the crude oil can be well detached from the coating surface. As a comparison, after a glass sheet without PHLWPU coating is pre-wetted by water and dripped with crude oil, it is found that the crude oil is still firmly adhered to the glass sheet, which shows that the PHLWPU coating has good crude oil-repellent performance.

[0098] Experimental Example 6

[0099] In this experimental example, PHLWPU (Example 1) is used as the experimental material to experiment on the oil-water separation.

[0100] The test method is to stir the mixture of 3 mL petroleum ether, kerosene, n-hexane, cyclohexane or kerosene, 300 mL water and 0.1 g Tween 80 at a speed of 5000 rpm for 5 min to obtain an oil-water emulsion. The oil-water separation test is carried out under the condition of vacuum pump pressurization.

[0101] The experimental results are shown in Figure 6 .

[0102] As can be seen from Figure 6 , the separation efficiency of the stainless steel mesh treated by PHLWPU for the water-in-petroleum ether, water-in-cyclohexane, water-in-n-hexane and water-in-kerosene emulsions is higher than 99.4%, which shows excellent oil-water separation performance.

[0103] Experimental Example 7

[0104] In this experimental example, PHLWPU (Example 1) is used as the experimental material to experiment on the self-repairing performance.

[0105] The test method is to make scratches on the surface of the coating with a scalpel, and put the damaged coating into an 80°C oven to record the situation before and after the coating is repaired by an optical microscope.

[0106] The experimental results are shown in Figure 7 .

[0107] Depend on Figure 7 As can be seen, when a scratch was made on the coating surface and then placed in an 80℃ oven for repair testing, the scratch on the PHLWPU coating surface disappeared after 5 minutes of repair time. This demonstrates that the PHLWPU coating has good repair performance.

[0108] Finally, it should be noted that the above embodiments are merely preferred embodiments of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a durable underwater superoleophobic coating with dynamic self-healing ability, characterized in that, The method comprises the following steps: taking IPDI, PTMEG, DBTDL and substance A as reaction raw materials to prepare a prepolymer containing an adhering group; adding a hydrophilic chain extender, a self-repairing chain extender, DMAC, triethylamine and deionized water in sequence to prepare a waterborne polyurethane LWPU dispersion with a self-repairing function; taking the waterborne polyurethane LWPU dispersion with the self-repairing function, substance B and substance C as reaction raw materials to obtain a solution with a hydrogen bond domain, and coating to form a coating; wherein the substance A is selected from E44 or E51; the substance B is selected from PVA or SA; and the substance C is selected from HEC or HPMC.

2. The method of claim 1, wherein, The method comprises the following steps: taking IPDI, PTMEG, DBTDL and substance A as reaction raw materials, and reacting at 80±5 ℃ for 3±0.5 h under N2 atmosphere to form a prepolymer containing an adhering group.

3. The method of claim 1, wherein, The hydrophilic chain extender is selected from DMPA.

4. The method of claim 1, wherein, The self-repairing chain extender is selected from LA.

5. The method of claim 1, wherein, After the prepolymer containing the adhering group is prepared, the hydrophilic chain extender DMPA is added to improve the water solubility and dispersibility of the polyurethane; then the temperature of the reaction system is increased to 90±5 ℃, the self-repairing chain extender is added to continue the reaction for 15±3 h, and the system viscosity is adjusted by adding DMAC; triethylamine is added to react for 15±3 min to neutralize the carboxyl group; and deionized water is added to fully disperse the prepolymer.

6. The method of claim 1, wherein, The substance B is a PVA solution with a mass fraction of 1%±0.5% or a SA solution with a mass fraction of 1%±0.5%.

7. The method of claim 1, wherein, The substance C is an HEC solution with a mass fraction of 1%±0.5% or an HPMC solution with a mass fraction of 1%±0.5%.

8. The method of claim 1, wherein, The solid content of the waterborne polyurethane LWPU dispersion with the self-repairing function is 13%±1%. The method comprises the following steps: taking the waterborne polyurethane LWPU dispersion with the self-repairing function, substance B and substance C as reaction raw materials, mixing and stirring at 50±5 ℃ for 2±0.5 h to form a hydrogen bond domain, and preparing a PHLWPU solution; wherein the amount ratio of the waterborne polyurethane LWPU dispersion with the self-repairing function, the substance B and the substance C is 2±0.1:1±0.1:1±0.

1.

9. The durable underwater superoleophobic coating with dynamic self-healing ability prepared by the method of any one of claims 1-8.

10. The application of the method of any one of claims 1-8 or the durable underwater superoleophobic coating with dynamic self-healing ability prepared by the method of any one of claims 1-8 in the field of oil-proofing.

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