Preparation method of green photothermal super-hydrophobic self-repairing coating
By using nanocomposite coating technology, hydrophobically modified carbon black grafted microcapsule composite powder was prepared and mixed with epoxy resin. This solved the problems of deterioration of autorheological properties and insufficient self-healing ability of photothermal superhydrophobic coatings in extremely cold sea areas, and achieved efficient photothermal de-icing and self-healing performance, adapting to extremely low temperature environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- UNIV OF SCI & TECH LIAONING
- Filing Date
- 2026-03-17
- Publication Date
- 2026-06-05
Smart Images
Figure CN122146132A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of self-healing coating technology, specifically relating to a method for preparing a green photothermal superhydrophobic self-healing coating. Background Technology
[0002] Traditional active de-icing technologies are energy-intensive and lack reliability in high sea states; therefore, passive de-icing technologies are considered a more energy-efficient solution. Among these, superhydrophobic coatings, inspired by the lotus leaf effect in nature, have become one of the most promising de-icing pathways due to their ability to achieve extreme repulsion of water droplets by constructing a micro-nano hierarchical rough structure and a low surface energy chemical layer, thereby significantly delaying icing and reducing ice adhesion. Photothermal coatings enhance the photothermal performance of the coating by incorporating materials with excellent photothermal properties, effectively converting solar energy into heat. However, coatings containing only photothermal de-icing materials have several drawbacks. On the one hand, water formed from melted ice remains on the surface of the photothermal material and refreezes; on the other hand, the photothermal material coating may be affected by solid and liquid contaminants, reducing light utilization and severely weakening its de-icing performance in outdoor applications.
[0003] Combining the self-cleaning properties of superhydrophobic surfaces with photothermal materials can ensure long-term de-icing capabilities; however, such coatings cannot effectively repair large-scale damage. Therefore, microencapsulation technology is widely used; however, under extreme low-temperature conditions, the self-rheological properties of this coating may deteriorate significantly, mainly because the viscosity of most liquid lubricants (such as mineral oils and synthetic oils) increases sharply or even completely solidifies at ultra-low temperatures.
[0004] Therefore, there is a need to develop a smart anti-corrosion coating with photothermal superhydrophobic properties to improve its adaptability to extremely low temperatures in applications in extremely cold sea areas. Summary of the Invention
[0005] In view of the aforementioned technical problems, this invention proposes a green method for preparing a photothermal superhydrophobic self-healing coating. This invention prepares hydrophobically modified carbon black grafted microcapsule composite powder, mixes it with epoxy resin, and then sprays it to obtain a photothermal superhydrophobic self-healing coating. This invention mainly employs a nanocomposite coating method to prepare a coating with a low surface energy micro-nano composite structure, which exhibits excellent superhydrophobicity. This composite powder not only improves the coating's density but also actively bonds to the epoxy resin coating, enhancing its durability. The superhydrophobic coating prepared by this invention not only possesses excellent self-cleaning and corrosion resistance but also photothermal de-icing and self-healing properties. This coating preparation method is low-cost, easy to operate, and applicable to a wide range of substrates.
[0006] To achieve the above objectives, the present invention employs the following technical solutions.
[0007] A method for preparing an environmentally friendly photothermal de-icing self-healing coating specifically includes the following steps: Step 1: Polydopamine-coated carbon black: Dopamine hydrochloride was ultrasonically dispersed in Tris-HCl buffer, and then carbon black was added. The container was then sealed and placed in a constant temperature water bath for stirring. After the reaction was completed, solid-liquid separation was performed by filtration. The solid was then washed with anhydrous ethanol and finally dried in a constant temperature drying oven to obtain polydopamine-coated carbon black. Step 2, Silane Modification of Carbon Black: The polydopamine-coated carbon black obtained in Step 1 was ultrasonically dispersed in an ethanol solution, and then hexadecyltrimethoxysilane was added. The container was then sealed and placed in a constant temperature water bath with magnetic stirring. After the reaction was completed, solid-liquid separation was performed by filtration, and the solid was washed with anhydrous ethanol. Finally, it was dried in a constant temperature drying oven to obtain silanized carbon black containing long-chain alkyl groups. Step 3: Preparation of hybrid wall microcapsules: Polymethyl methacrylate and Mg-MOF-74 were ultrasonically dispersed in dichloromethane to prepare solution A; gelatin and polyvinyl alcohol were ultrasonically dispersed in deionized water to prepare solution B; solution A was added dropwise to solution B, followed by dehydrated castor oil. The container was then placed in a constant temperature water bath and magnetically stirred. After the reaction was completed, solid-liquid separation was performed by filtration. The solid was then washed with anhydrous ethanol and finally dried in a constant temperature drying oven to obtain PMMA@DCO@Mg-MOF microcapsules. Step 4: Grafting microcapsules with silanized carbon black: The silanized carbon black containing long-chain alkyl groups obtained in Step 2 was ultrasonically dispersed in Tris-HCl buffer to prepare suspension A. The PMMA@DCO@Mg-MOF microcapsules obtained in Step 3 were then ultrasonically dispersed into suspension A. The mixture was then sealed and placed in a constant temperature water bath with magnetic stirring. Finally, it was dried in a constant temperature drying oven to obtain a hybrid of silanized carbon black and microcapsules. Step 5, Mixing and Spraying: Ultrasonically mix epoxy resin EP-44, epoxy resin curing agent polyamide 650, solvent anhydrous ethanol and silanized carbon black with microcapsule hybrid to obtain a mixture; then spray the mixture onto the substrate and dry at a constant temperature to obtain a photothermal de-icing self-healing coating.
[0008] Further, in step 1, 0.5-2 g of dopamine hydrochloride, 100-150 mL of Tris-HCl buffer, ultrasonically dispersed for 1-2 h, 0.5-1 g of carbon black, reacted in a constant temperature water bath at 35-40 ℃ for 12-24 h; drying oven parameters: drying at 50-60 ℃ for 12-24 h.
[0009] Further, in step 2, 0.5-1 g of polydopamine-coated carbon black, 0.5-1 g of hexadecyltrimethoxysilane, and 20-25 ml of ethanol solution are ultrasonically dispersed for 1-2 h; reacted in a constant temperature water bath at 35-40℃ for 12-24 h; and dried at 50-60℃ for 12-24 h.
[0010] Further, in step 3, 0.1-0.3 g of Mg-MOF-74, 1-1.5 g of polymethyl methacrylate, and 60-80 mL of dichloromethane are ultrasonically dispersed for 1-2 h; 1-1.5 ml of dehydrated castor oil is reacted in a constant temperature water bath at 35-40 ℃ for 5-6 h; and the drying oven parameters are: drying at 40-50 ℃ for 12-24 h.
[0011] Further, in step 4, 0.5-1 g of silanized carbon black containing long-chain alkyl groups is ultrasonically dispersed for 1-2 h; 1-2 g of microcapsules are ultrasonically dispersed for 1-2 h, and reacted in a constant temperature water bath at 35-40 ℃ for 12-24 h; drying oven parameters: drying at 50-60 ℃ for 12-24 h.
[0012] Further, in step 5, 1-2 g of epoxy resin EP-44, 1-2 g of polyamide 650, 0.1-0.2 g of anhydrous ethanol and 0.5-1 g of silanized carbon black and microcapsule hybrid are ultrasonically mixed at 35-40 ℃ for 20-30 min; the coating drying parameters are: drying at 50-60 ℃ for 12-24 h.
[0013] The present invention first coats carbon black with polydopamine, and then oxidizes and polymerizes dopamine in a weakly alkaline environment, thereby forming a polydopamine film with abundant active groups on the surface of carbon black in situ, thus obtaining polydopamine-coated carbon black powder.
[0014] Then, the active groups of the polydopamine-coated carbon black powder are subjected to organic covalent chemical modification. The carbon black is functionalized with a silane coupling agent (hexadecyltrimethoxysilane). The silanol generated by the hydrolysis of the silane coupling agent condenses into strong Si-O-Si covalent bonds on the powder surface. Taking advantage of the low surface energy of long-chain alkyl groups, a hydrophobic network is formed, thereby obtaining carbon black powder with low surface energy.
[0015] Then, hybrid wall microcapsules were prepared by dispersing polymethyl methacrylate and Mg-MOF-74 in dichloromethane as hybrid wall materials and using dehydrated castor oil as core material. During the volatilization process, polymethyl methacrylate and Mg-MOF-74 co-deposited and coated the dehydrated castor oil droplets to form PMMA@DCO@Mg-MOF composite wall material microcapsules.
[0016] This invention utilizes the bondability of alkyl and carboxyl groups to graft silanized carbon black onto the wall material of hybrid microcapsules in a weakly alkaline environment, thereby preparing a hybrid of bonded carbon black and microcapsules. This results in a powder that not only possesses superhydrophobicity but also the self-healing ability of the microcapsules. Taking advantage of the composability of this hybrid with epoxy resin, a functional coating is prepared. The hybrid is uniformly dispersed in an epoxy resin coating, ultrasonically dispersed to form a stable mixture, and then sprayed onto the substrate surface. After curing, a composite coating is obtained. In this coating, the grafted carbon black imparts excellent photothermal conversion capabilities to achieve de-icing functionality. Simultaneously, the rupture of the microcapsules allows for the release of dehydrated castor oil core material, enabling self-repair of damaged areas in the coating. The hydrophobic modification layer of the carbon black and the hybrid structure of the microcapsules together ensure the superhydrophobicity and durability of the coating.
[0017] Compared with existing technologies, the beneficial effects of the present invention are as follows.
[0018] This invention synthesizes non-fluorinated low surface energy particles and uses non-fluorinated superhydrophobic carbon black grafted modified microcapsules to prepare a photothermal superhydrophobic self-healing coating. The use of non-fluorinated coatings reduces costs and protects the environment; the nanocomposite coating is composed of nanoparticle fillers and organic polymer resin coating.
[0019] 1. Carbon black and microcapsules are bonded together, and then bonded to the epoxy resin coating, which makes the coating system a stable whole.
[0020] 2. The superhydrophobic top layer and self-healing bottom layer structure are optimized into a single layer that simultaneously possesses superhydrophobic and self-healing functions, in order to simplify the cumbersome preparation and usage processes.
[0021] 3. This invention combines epoxy resin coating technology with photothermal de-icing self-healing powder, which ensures that the coating can not only bond with the substrate, but also give full play to the photothermal de-icing and self-healing functions of the powder.
[0022] 4. This invention uses low-cost carbon black as a photothermal material and synthesizes a carbon black-microcapsule hybrid that is combined with an epoxy resin coating, which can improve the mechanical properties of the coating.
[0023] 5. This invention uses polydopamine-coated carbon black, which provides de-icing function for epoxy resin coating due to synergistic photothermal effect; the polydopamine-coated carbon black is hydrophobically silanized to provide superhydrophobic and corrosion-resistant function for epoxy resin coating; at the same time, the non-fluorine superhydrophobic carbon black bonded microcapsules provide self-healing function for epoxy resin coating.
[0024] 6. The formula used in this invention is fluorine-free and phosphorus-free, and the waste liquid is non-toxic and pollution-free, requiring no special treatment. The number of pharmaceutical ingredients is less compared to other existing formulas, making it economical and environmentally friendly. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the coating.
[0026] Figure 2 This is a schematic diagram of a microcapsule hybrid of grafted modified carbon black.
[0027] Wherein: 1-epoxy resin, 2-matrix, 3-microcapsule, 4-modified carbon black. Detailed Implementation
[0028] The present invention will now be described in detail, but the scope of the present invention is not limited to the embodiments described below.
[0029] A method for preparing an environmentally friendly photothermal de-icing self-healing coating specifically includes the following steps: Step 1: Polydopamine-coated carbon black: Dopamine hydrochloride was ultrasonically dispersed in Tris-HCl buffer, and then carbon black was added. The container was then sealed and placed in a constant temperature water bath with stirring. During this process, the dissolved dopamine hydrochloride underwent oxidative polymerization under weakly alkaline conditions to form polydopamine, which then reacted with carbon black, polymerizing in situ on its surface to form a PDA film. After the reaction, solid-liquid separation was performed by filtration, and the solid was washed with anhydrous ethanol. Finally, it was dried in a constant temperature drying oven to obtain polydopamine-coated carbon black. The reaction parameters were: 0.5-2 g dopamine hydrochloride, 100-150 mL Tris-HCl buffer, ultrasonic dispersion for 1-2 h, 0.5-1 g carbon black, reaction in a constant temperature water bath at 35-40 ℃ for 12-24 h; drying oven parameters: 50-60 ℃ for 12-24 h. Step 2, Silane Modification of Carbon Black: The polydopamine-coated carbon black obtained in Step 1 was ultrasonically dispersed in an ethanol solution, and then hexadecyltrimethoxysilane was added. The container was then sealed and placed in a constant temperature water bath with magnetic stirring. During this process, water helped hydrolyze the hexadecyltrimethoxysilane, which hydrolyzed into silanol, and then reacted with carbon black to form a strong Si-O-Si covalent bond, anchoring the long alkyl chain on its surface. After the reaction, solid-liquid separation was performed by filtration, and the solid was washed with anhydrous ethanol. Finally, it was dried in a constant temperature drying oven to obtain silanized carbon black containing long-chain alkyl groups. The reaction parameters were: 0.5-1 g of polydopamine-coated carbon black, 0.5-1 g of hexadecyltrimethoxysilane, 20-25 ml of ethanol solution, ultrasonic dispersion for 1-2 h; reaction in a constant temperature water bath at 35-40 ℃ for 12-24 h; drying oven parameters: drying at 50-60 ℃ for 12-24 h. Step 3: Preparation of hybrid wall microcapsules: Polymethyl methacrylate (PMMA) and Mg-MOF-74 were ultrasonically dispersed in dichloromethane to prepare solution A; gelatin and polyvinyl alcohol were ultrasonically dispersed in deionized water to prepare solution B; solution A was added dropwise to solution B, followed by dehydrated castor oil. The container was then placed in a constant temperature water bath and magnetically stirred. During this process, dichloromethane evaporated, and PMMA and Mg-MOF-74 coated the dehydrated castor oil. After the reaction, solid-liquid separation was performed by filtration, and the solid was washed with anhydrous ethanol. Finally, it was dried in a constant temperature drying oven to obtain PMMA@DCO@Mg-MOF microcapsules; Mg-MOF-74 0.1-0.3 g, PMMA 1-1.5 g, dichloromethane 60-80 mL, ultrasonic dispersion for 1-2 h; dehydrated castor oil 1-1.5 ml, reaction in a constant temperature water bath at 35-40 ℃ for 5-6 h; drying oven parameters: 40-50 Dry at ℃ for 12-24 hours; Step 4: Grafting silanized carbon black onto microcapsules: The silanized carbon black containing long-chain alkyl groups obtained in Step 2 was ultrasonically dispersed in Tris-HCl buffer to prepare suspension A. The PMMA@DCO@Mg-MOF microcapsules obtained in Step 3 were then ultrasonically dispersed into suspension A. The mixture was then sealed and placed in a constant-temperature water bath with magnetic stirring. During this process, the long-chain alkyl groups on the surface of the silanized carbon black bonded to the activated carboxyl groups on the surface of the microcapsules, grafting the silanized carbon black onto the hybrid wall microcapsules. Finally, the mixture was dried in a constant-temperature drying oven to obtain a silanized carbon black and microcapsule hybrid. The reaction conditions were: 0.5-1 g of silanized carbon black containing long-chain alkyl groups, ultrasonically dispersed for 1-2 h; 1-2 g of microcapsules, ultrasonically dispersed for 1-2 h, reacted in a constant-temperature water bath at 35-40 ℃ for 12-24 h; drying oven parameters: 50-60 ℃ for 12-24 h. Step 5, Mixing and Spraying: Ultrasonically mix epoxy resin EP-44, epoxy resin curing agent polyamide 650, solvent anhydrous ethanol, and silanized carbon black with the microcapsule hybrid to obtain a mixture; then spray the mixture onto the substrate and dry at a constant temperature. Mix 1-2 g of epoxy resin EP-44, 1-2 g of polyamide 650, 0.1-0.2 g of anhydrous ethanol, and 0.5-1 g of silanized carbon black with the microcapsule hybrid at 35-40 ℃ for 20-30 min; drying parameters: dry at 50-60 ℃ for 12-24 h; to obtain a photothermal de-icing self-healing coating.
[0030] Example 1.
[0031] A method for preparing an environmentally friendly photothermal de-icing self-healing coating specifically includes the following steps: 1) Polydopamine-coated carbon black process: 2 g of dopamine hydrochloride was placed in 150 ml of Tris-HCl buffer and ultrasonically dispersed for 2 h. After adding 1 g of carbon black, the mixture was reacted in a constant temperature water bath at 40 ℃ for 24 h. After the reaction was completed, solid-liquid separation was performed by filtration. The solid was then washed with anhydrous ethanol and finally dried in a constant temperature drying oven at 60 ℃ for 24 h to obtain polydopamine-coated carbon black. 2) Silane modification process for carbon black: 1 g of polydopamine-coated carbon black was placed in 25 ml of ethanol solution, and 1 g of hexadecyltrimethoxysilane was added. The mixture was ultrasonically dispersed for 2 h. The mixture was then reacted in a constant temperature water bath at 40 ℃ for 24 h. After the reaction was completed, the solid and liquid were separated by filtration. The solid was then washed with anhydrous ethanol and finally dried in a constant temperature drying oven at 60 ℃ for 24 h to obtain silanized carbon black containing long-chain alkyl groups. 3) Preparation of hybrid wall microcapsules: 1.5 g of polymethyl methacrylate and 0.3 g of Mg-MOF-74 were ultrasonically dispersed in 80 ml of dichloromethane to prepare solution A; 0.5 g of gelatin and 0.4 g of polyvinyl alcohol were ultrasonically dispersed in deionized water to prepare solution B; solution A was added dropwise to solution B, and then 1.5 ml of dehydrated castor oil was added. The container was then placed in a 40 ℃ constant temperature water bath for 6 h. After the reaction was completed, solid-liquid separation was performed by filtration, and the solid was washed with anhydrous ethanol. Finally, it was dried in a constant temperature drying oven at 50 ℃ for 24 h to obtain PMMA@DCO@Mg-MOF microcapsules. 4) Silanized carbon black grafted microcapsules: 1 g of silanized carbon black containing long-chain alkyl groups obtained in step 2 was ultrasonically dispersed in Tris-HCl buffer for 2 h to prepare suspension A. Then, 2 g of PMMA@DCO@Mg-MOF microcapsules obtained in step 3 were ultrasonically dispersed in suspension A for 2 h. The mixture was then sealed and placed in a 40 ℃ constant temperature water bath for 24 h. Finally, it was dried in a constant temperature drying oven at 60 ℃ for 24 h to obtain a silanized carbon black-microcapsule hybrid. 5) Mixed spraying process: 2 g EP-44, 2 g polyamide 650, 0.2 g anhydrous ethanol and 1 g silanized carbon black and microcapsule hybrid were ultrasonically mixed at 40 ℃ for 30 min; coating drying parameters: dried at 60 ℃ for 24 h. Sprayed onto AH36 steel plate.
[0032] Example 2.
[0033] A method for preparing an environmentally friendly photothermal de-icing self-healing coating specifically includes the following steps: 1) Polydopamine-coated carbon black process: 1 g of dopamine hydrochloride was placed in 125 ml of Tris-HCl buffer and ultrasonically dispersed for 1.5 h. 0.75 g of carbon black was added and reacted in a constant temperature water bath at 38 ℃ for 18 h. After the reaction, solid-liquid separation was performed by filtration. The solid was then washed with anhydrous ethanol and finally dried in a constant temperature drying oven at 55 ℃ for 18 h to obtain polydopamine-coated carbon black. 2) Silane modification process for carbon black: 0.75 g of polydopamine-coated carbon black was placed in 22.5 ml of ethanol solution and ultrasonically dispersed for 1.5 h; 0.75 g of hexadecyltrimethoxysilane was added and reacted in a constant temperature water bath at 38 ℃ for 18 h; after the reaction, solid-liquid separation was performed by filtration, and the solid was washed with anhydrous ethanol. Finally, it was dried in a constant temperature drying oven at 55 ℃ for 18 h to obtain silanized carbon black containing long-chain alkyl groups. 3) Preparation of hybrid wall microcapsules: 0.75 g of polymethyl methacrylate and 0.2 g of Mg-MOF-74 were ultrasonically dispersed in 70 ml of dichloromethane to prepare solution A; 0.5 g of gelatin and 0.4 g of polyvinyl alcohol were ultrasonically dispersed in deionized water to prepare solution B; solution A was added dropwise to solution B, and then 1.25 ml of dehydrated castor oil was added. The container was then placed in a 38℃ constant temperature water bath for 5.5 h. After the reaction, solid-liquid separation was performed by filtration, and the solid was washed with anhydrous ethanol. Finally, it was dried in a constant temperature drying oven at 45 ℃ for 18 h to obtain PMMA@DCO@Mg-MOF microcapsules. 4) Silanized carbon black grafted microcapsules: 0.75 g of silanized carbon black containing long-chain alkyl groups obtained in step 2 was ultrasonically dispersed for 1.5 h in Tris-HCl buffer to prepare suspension A. Then, 1.5 g of PMMA@DCO@Mg-MOF microcapsules obtained in step 3 were ultrasonically dispersed in suspension A for 1.5 h. The mixture was then sealed and reacted in a 38 ℃ constant temperature water bath for 18 h. Finally, it was dried in a constant temperature drying oven at 55 ℃ for 18 h to obtain a silanized carbon black-microcapsule hybrid. 5) Mixed spraying process: 1.5 g EP-44, 1.5 g polyamide 650, 0.15 g anhydrous ethanol and 0.75 g silanized carbon black and microcapsule hybrid were ultrasonically mixed at 38 ℃ for 25 min; coating drying parameters: dried at 55 ℃ for 18 h. Sprayed onto AH36 steel plate.
[0034] Example 3.
[0035] A method for preparing an environmentally friendly photothermal de-icing self-healing coating specifically includes the following steps: 1) Polydopamine-coated carbon black process: 0.5 g of dopamine hydrochloride was placed in 100 ml of Tris-HCl buffer and ultrasonically dispersed for 1 h. After adding 0.5 g of carbon black, the mixture was reacted in a constant temperature water bath at 35 ℃ for 12 h. After the reaction was completed, solid-liquid separation was performed by filtration. The solid was then washed with anhydrous ethanol and finally dried in a constant temperature drying oven at 50 ℃ for 12 h to obtain polydopamine-coated carbon black. 2) Silane modification process for carbon black: 0.5 g of polydopamine-coated carbon black was placed in 20 ml of ethanol solution and ultrasonically dispersed for 1 h; 0.5 g of hexadecyltrimethoxysilane was added and reacted in a constant temperature water bath at 35 ℃ for 12 h; after the reaction, solid-liquid separation was performed by filtration, and the solid was washed with anhydrous ethanol. Finally, it was dried in a constant temperature drying oven at 50 ℃ for 12 h to obtain silanized carbon black containing long-chain alkyl groups. 3) Preparation of hybrid wall microcapsules: 1 g of polymethyl methacrylate and 0.1 g of Mg-MOF-74 were ultrasonically dispersed in 60 ml of dichloromethane to prepare solution A; 0.5 g of gelatin and 0.4 g of polyvinyl alcohol were ultrasonically dispersed in deionized water to prepare solution B; solution A was added dropwise to solution B, followed by 1 ml of dehydrated castor oil. The container was then placed in a 35 ℃ constant temperature water bath for 5 h. After the reaction, solid-liquid separation was performed by filtration, and the solid was washed with anhydrous ethanol. Finally, the solid was dried in a constant temperature drying oven at 40 ℃ for 12 h to obtain PMMA@DCO@Mg-MOF microcapsules. 4) Silanized carbon black grafted microcapsules: 0.5 g of silanized carbon black containing long-chain alkyl groups obtained in step 2 was ultrasonically dispersed in Tris-HCl buffer for 1 h to prepare suspension A. Then, 1 g of PMMA@DCO@Mg-MOF microcapsules obtained in step 3 were ultrasonically dispersed in suspension A for 1 h. The mixture was then sealed and placed in a 35 ℃ constant temperature water bath for 12 h. Finally, it was dried in a constant temperature drying oven at 50 ℃ for 12 h to obtain a silanized carbon black-microcapsule hybrid. 5) Mixed spraying process: 1 g EP-44, 1 g polyamide 650, 0.1 g anhydrous ethanol and 0.5 g silanized carbon black and microcapsule hybrid were ultrasonically mixed at 35 ℃ for 20 min; coating drying parameters: dried at 50 ℃ for 12 h. Sprayed onto AH36 steel plate.
[0036] Comparative Example 1.
[0037] The purpose of this comparative example is to verify the effect on coating performance when carbon black and microcapsule grafting are not performed.
[0038] 1) Polydopamine-coated carbon black process: 1 g of dopamine hydrochloride was placed in 125 ml of Tris-HCl buffer and ultrasonically dispersed for 1.5 h. 0.75 g of carbon black was added and reacted in a constant temperature water bath at 38 ℃ for 18 h. After the reaction, solid-liquid separation was performed by filtration. The solid was then washed with anhydrous ethanol and finally dried in a constant temperature drying oven at 55 ℃ for 18 h to obtain polydopamine-coated carbon black. 2) Silane modification process for carbon black: 0.75 g of polydopamine-coated carbon black was placed in 22.5 ml of ethanol solution and ultrasonically dispersed for 1.5 h; 0.75 g of hexadecyltrimethoxysilane was added and reacted in a constant temperature water bath at 38 ℃ for 18 h; after the reaction, solid-liquid separation was performed by filtration, and the solid was washed with anhydrous ethanol. Finally, it was dried in a constant temperature drying oven at 55 ℃ for 18 h to obtain silanized carbon black containing long-chain alkyl groups. 3) Preparation of hybrid wall microcapsules: 0.75 g of polymethyl methacrylate and 0.2 g of Mg-MOF-74 were ultrasonically dispersed in 70 ml of dichloromethane to prepare solution A; 0.5 g of gelatin and 0.4 g of polyvinyl alcohol were ultrasonically dispersed in deionized water to prepare solution B; solution A was added dropwise to solution B, followed by 1.25 ml of dehydrated castor oil. The container was then placed in a 38°C constant temperature water bath for 5.5 h. After the reaction, solid-liquid separation was performed by filtration, and the solid was washed with anhydrous ethanol. Finally, the solid was dried in a constant temperature drying oven at 38°C for 18 h to obtain PMMA@DCO@Mg-MOF microcapsules. 4) Mixed spraying process: 1.5 g EP-44, 1.5 g polyamide 650, 0.15 g anhydrous ethanol, 0.5 g carbon black and 0.5 g microcapsules were ultrasonically mixed at 38 ℃ for 25 min; coating drying parameters: drying at 55 ℃ for 18 h. The mixture was sprayed onto AH36 steel plate. This yielded the Comparative Example 1 sample.
[0039] Comparative Example 2.
[0040] The purpose of this comparative example is to verify the effect on coating performance when carbon black is not coated with polydopamine.
[0041] 1) Silane modification process for carbon black: 0.75 g of carbon black was placed in 22.5 ml of ethanol solution and ultrasonically dispersed for 1.5 h; 0.75 g of hexadecyltrimethoxysilane was added and reacted in a constant temperature water bath at 38 ℃ for 18 h; after the reaction, solid-liquid separation was performed by filtration, and then the solid was washed with anhydrous ethanol. Finally, it was dried in a constant temperature drying oven at 55 ℃ for 18 h to obtain silanized carbon black containing long-chain alkyl groups. 2) Preparation of hybrid wall microcapsules: 0.75 g of polymethyl methacrylate and 0.2 g of Mg-MOF-74 were ultrasonically dispersed in 70 ml of dichloromethane to prepare solution A; 0.5 g of gelatin and 0.4 g of polyvinyl alcohol were ultrasonically dispersed in deionized water to prepare solution B; solution A was added dropwise to solution B, followed by 1.25 ml of dehydrated castor oil. The container was then placed in a 38°C water bath for 5.5 h. After the reaction, solid-liquid separation was performed by filtration, and the solid was washed with anhydrous ethanol. Finally, the solid was dried in a constant temperature drying oven at 38°C for 18 h to obtain PMMA@DCO@Mg-MOF microcapsules. 3) Silanized carbon black grafted microcapsules: 0.75 g of silanized carbon black containing long-chain alkyl groups obtained in step 2 was ultrasonically dispersed for 1.5 h in Tris-HCl buffer to prepare suspension A. Then, 1.5 g of PMMA@DCO@Mg-MOF microcapsules obtained in step 3 were ultrasonically dispersed in suspension A for 1.5 h. The mixture was then sealed and reacted in a 38 ℃ constant temperature water bath for 18 h. Finally, it was dried in a constant temperature drying oven at 55 ℃ for 18 h to obtain a silanized carbon black-microcapsule hybrid. 4) Mixed spraying process: 1.5 g EP-44, 1.5 g polyamide 650, 0.15 g anhydrous ethanol and 0.75 g silanized carbon black and microcapsule hybrid were ultrasonically mixed at 38 ℃ for 25 min; coating drying parameters: drying at 55 ℃ for 18 h. Sprayed onto AH36 steel plate.
[0042] Performance testing 1. Superhydrophobic performance test: The water contact angle and roll-off angle were measured using a contact angle measuring instrument. Samples obtained from Examples 1-3 and Comparative Examples 1-2 were used, and the powder was adhered to the surface of an AH36 steel plate using double-sided adhesive tape to measure the water contact angle of the powder.
[0043] 2. Anti-icing performance test: The anti-icing performance of superhydrophobic coatings is usually characterized by the freezing time of water droplets. Samples obtained in Examples 1-3 and Comparative Examples 1-2 were tested respectively. The coatings were placed in a refrigerator at a temperature of -10 ℃ and a humidity of 35±5%, forming a 2 cm ice layer on the coating surface to simulate icing. Then, a xenon lamp was used at 1 kW / m². 2 De-icing tests were conducted under irradiation.
[0044] 3. Adhesion Test: The durability of superhydrophobic coatings is typically characterized by a pull-off test. Samples obtained in Examples 1-3 and Comparative Examples 1-2 were tested respectively. A load clamp was fixed to the coating surface, and a vertical tensile force was applied to the test surface. The force applied to the load clamp was gradually increased and observed until the material separated. The pull-off strength was calculated based on the maximum indicated load, instrument calibration data, and the initial area of the applied stress.
[0045] 4. Corrosion Resistance Test: Electrochemical impedance spectroscopy was used to study corrosion resistance. Samples obtained in Examples 1-3 and Comparative Examples 1-2 were tested. The main procedures were as follows: an electrode system consisting of a silver-silver chloride electrode as the reference electrode, a platinum sheet as the counter electrode, and the test steel sample as the working electrode. The area of the sample not wrapped with insulating tape was 1 cm². 2 Before testing, the sample was immersed in a 3.5% NaCl solution for 30 minutes. The entire test was conducted at a high frequency of 1×10⁻⁶. 5 Hz to low frequency 1×10 -2 The operation is performed at Hz, using a positive selection perturbation voltage (AC signal) of 10 mV.
[0046] Table 1. Performance test results of coatings in the examples and comparative examples.
[0047] As shown in Table 1, Examples 1-3 exhibit significantly better overall performance than Comparative Examples 1 and 2, indicating that the hybrid wall microcapsule grafted modified carbon black used in this invention has significant advantages in hydrophobicity, anti-icing, adhesion, and corrosion resistance. Among them, Example 2 shows the best performance in all indicators and is considered the optimal solution.
[0048] Regarding hydrophobic properties, the water contact angles of the examples were all greater than those of the comparative examples. In particular, the water contact angle of Example 2 was 158.7°, indicating that it had the best hydrophobic effect and could effectively prevent water droplets from freezing on the coating surface. In contrast, the water contact angles of Comparative Examples 1 and 2 were 153.4° and 154.3°, respectively, indicating that the powder was not stable without grafting or polydopamine coating, which affected the coating performance.
[0049] Regarding anti-icing performance, the freezing time of Example 2 was 1740 s, significantly higher than that of Example 1 (1680 s) and Example 3 (1640 s), while the freezing time of the comparative examples was only 1580 s to 1400 s. This result indicates that the polydopamine-coated carbon black synergistic system used in this invention can effectively delay the freezing of water droplets on the coating surface and improve the de-icing performance of the coating.
[0050] Regarding adhesion, the adhesion of the example samples was higher than that of the comparative samples, with Example 2 showing the highest adhesion at 3.9 MPa, exhibiting the best adhesion effect. The adhesion of Comparative Examples 1 and 2 was 3.3 MPa and 3.1 MPa, respectively, indicating that the comparative sample lacked sufficient stability, leading to a decrease in coating adhesion.
[0051] Regarding corrosion resistance, Examples 1 to 3 exhibited good corrosion resistance in 3.5% NaCl solution. This is because the addition of the composite powder increased the crosslinking density of the coating, filled micropores and other defects on the coating surface, inhibited the further expansion of the corrosion process on the metal surface, and demonstrated good self-healing ability, preventing the penetration of corrosive media. In contrast, the impedance modulus values of Comparative Examples 1 and 2 decreased significantly, indicating that the powder lacked sufficient stability, resulting in insufficient barrier properties of the coating and allowing corrosive media to penetrate.
[0052] In summary, the embodiments, especially Embodiment 2, showed the best performance in all four aspects: hydrophobicity, anti-icing, adhesion, and corrosion resistance, and were superior to the comparative embodiments.
Claims
1. A method for preparing an environmentally friendly photothermal de-icing self-healing coating, characterized in that, Specifically, the steps include the following: Step 1: Polydopamine-coated carbon black: Dopamine hydrochloride was ultrasonically dispersed in Tris-HCl buffer, and then carbon black was added. The container was then sealed and placed in a constant temperature water bath for stirring. After the reaction was completed, solid-liquid separation was performed by filtration. The solid was then washed with anhydrous ethanol and finally dried in a constant temperature drying oven to obtain polydopamine-coated carbon black. Step 2, Silane Modification of Carbon Black: The polydopamine-coated carbon black obtained in Step 1 was ultrasonically dispersed in an ethanol solution, and then hexadecyltrimethoxysilane was added. The container was then sealed and placed in a constant temperature water bath with magnetic stirring. After the reaction was completed, solid-liquid separation was performed by filtration, and the solid was washed with anhydrous ethanol. Finally, it was dried in a constant temperature drying oven to obtain silanized carbon black containing long-chain alkyl groups. Step 3: Preparation of hybrid wall microcapsules: Polymethyl methacrylate and Mg-MOF-74 were ultrasonically dispersed in dichloromethane to prepare solution A; gelatin and polyvinyl alcohol were ultrasonically dispersed in deionized water to prepare solution B; solution A was added dropwise to solution B, followed by dehydrated castor oil. The container was then placed in a constant temperature water bath and magnetically stirred. After the reaction was completed, solid-liquid separation was performed by filtration. The solid was then washed with anhydrous ethanol and finally dried in a constant temperature drying oven to obtain PMMA@DCO@Mg-MOF microcapsules. Step 4: Grafting microcapsules with silanized carbon black: The silanized carbon black containing long-chain alkyl groups obtained in Step 2 was ultrasonically dispersed in Tris-HCl buffer to prepare suspension A. The PMMA@DCO@Mg-MOF microcapsules obtained in Step 3 were then ultrasonically dispersed into suspension A. The mixture was then sealed and placed in a constant temperature water bath with magnetic stirring. Finally, it was dried in a constant temperature drying oven to obtain a hybrid of silanized carbon black and microcapsules. Step 5, Mixing and Spraying: Ultrasonically mix epoxy resin EP-44, epoxy resin curing agent polyamide 650, solvent anhydrous ethanol and silanized carbon black with microcapsule hybrid to obtain a mixture; then spray the mixture onto the substrate and dry at a constant temperature to obtain a photothermal de-icing self-healing coating.
2. The method for preparing the environmentally friendly photothermal de-icing self-healing coating according to claim 1, characterized in that, In step 1, 0.5-2 g of dopamine hydrochloride, 100-150 mL of Tris-HCl buffer solution, ultrasonic dispersion for 1-2 h, 0.5-1 g of carbon black, and reaction in a constant temperature water bath at 35-40 ℃ for 12-24 h; drying oven parameters: drying at 50-60 ℃ for 12-24 h.
3. The method for preparing the environmentally friendly photothermal de-icing self-healing coating according to claim 1, characterized in that, In step 2, 0.5-1 g of polydopamine-coated carbon black, 0.5-1 g of hexadecyltrimethoxysilane, and 20-25 ml of ethanol solution are ultrasonically dispersed for 1-2 h; the mixture is then reacted in a constant temperature water bath at 35-40 ℃ for 12-24 h; and dried at 50-60 ℃ for 12-24 h.
4. The method for preparing the environmentally friendly photothermal de-icing self-healing coating according to claim 1, characterized in that, In step 3, 0.1-0.3 g of Mg-MOF-74, 1-1.5 g of polymethyl methacrylate, and 60-80 mL of dichloromethane are ultrasonically dispersed for 1-2 h; 1-1.5 ml of dehydrated castor oil is reacted in a constant temperature water bath at 35-40 ℃ for 5-6 h; and the drying oven parameters are: drying at 40-50 ℃ for 12-24 h.
5. The method for preparing the environmentally friendly photothermal de-icing self-healing coating according to claim 1, characterized in that, In step 4, 0.5-1 g of silanized carbon black containing long-chain alkyl groups is ultrasonically dispersed for 1-2 h; 1-2 g of microcapsules are ultrasonically dispersed for 1-2 h, and reacted in a constant temperature water bath at 35-40 ℃ for 12-24 h; drying oven parameters: drying at 50-60 ℃ for 12-24 h.
6. The method for preparing the environmentally friendly photothermal de-icing self-healing coating according to claim 1, characterized in that, In step 5, 1-2 g of epoxy resin EP-44, 1-2 g of polyamide 650, 0.1-0.2 g of anhydrous ethanol and 0.5-1 g of silanized carbon black and microcapsule hybrid are ultrasonically mixed at 35-40 ℃ for 20-30 min; the coating drying parameters are: drying at 50-60 ℃ for 12-24 h.