Composite photo-thermal self-lubricating super-hydrophobic ice-inhibiting coating as well as preparation method and application thereof

Abstract

The invention relates to the technical field of protection of wind power generation equipment, in particular to a composite photo-thermal self-lubricating super-hydrophobic ice-inhibiting coating as well as a preparation method and application thereof. The coating comprises the following components in parts by weight: 0.3-0.6 part of a multi-walled carbon nanotube subjected to surface treatment; 0.2 to 0.4 part of nano zirconium oxide subjected to surface treatment; 0.06 to 0.09 part of a fluorine-containing silane coupling agent; 0.8 to 1.4 parts of an acrylate monomer mixture; 0.01 to 0.02 part of an initiator; and 0.3 to 0.45 part of an isocyanate curing agent. According to the coating disclosed by the invention, passive temperature rise under sunshine is realized to delay icing, and natural deicing is realized by virtue of low surface energy and a lubricant in the absence of sunshine, so that the operation safety and economical efficiency of the wind driven generator blade in a cold region are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind power generation equipment protection, and in particular to a composite light-heat self-lubricating super-hydrophobic ice-repellent coating as well as a preparation method and application thereof. BACKGROUND

[0002] In cold regions and offshore wind farms, the surface of the wind turbine blade is prone to icing in a low-temperature and high-humidity environment, which leads to a decrease in aerodynamic performance, an increase in load, an increase in operation safety risk, and a significant increase in maintenance cost. The current common ice prevention and removal methods mainly include active and passive methods. The active method, such as electric heating and hot air circulation, relies on external energy input and has high energy consumption. The passive method mainly uses surface functional coating to achieve protection by reducing ice adhesion or delaying icing, but often has limitations in long-term durability and environmental adaptability.

[0003] In the existing passive ice-repellent coating, a representative technology is to combine light-heat materials with super-hydrophobic structures to delay or melt ice layer by absorbing solar radiation to heat the coating, and to reduce the adhesion of ice by using micro-nano rough structures to reduce surface energy. For example, a known light-heat ice-repellent super-hydrophobic coating uses carbon nanotubes and carbon black as black light-heat fillers, and forms a surface with micro-nano structures through two solidifications, which can heat and remove ice under light, and reduce water droplet retention by super-hydrophobicity. Another existing technology introduces a lubricant to form a biomimetic ice-repellent coating, which reduces ice adhesion and improves ice removal effect by forming a lubricating layer on the surface of the coating.

[0004] However, the above-mentioned existing technologies still have the following problems in practical application: The light-heat coating using carbon-based black fillers has high light-heat conversion efficiency, but its dark appearance is not coordinated with the light-colored coating commonly used for wind turbine blades, affecting the overall appearance and visual consistency. Secondly, the coating relying on micro-nano rough structures to maintain super-hydrophobicity is prone to surface structure wear or pollution under the action of external factors such as wind sand, raindrops and ultraviolet radiation for a long time, resulting in a decrease in hydrophobicity and an increase in ice adhesion. Thirdly, the coating with added liquid lubricant can reduce ice adhesion in the short term, but the lubricant is prone to volatilization, migration or loss in outdoor environment, making it difficult to maintain a stable lubricating interface for a long time, and the ice-repellent performance decreases significantly with the use time, requiring frequent maintenance or re-coating. In addition, the above-mentioned coatings are often not optimized in terms of mechanical strength and substrate adhesion, and may have problems such as peeling and cracking under harsh weather conditions, affecting the long-term service reliability. SUMMARY

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a composite photothermal self-lubricating superhydrophobic anti-icing coating, its preparation method, and its application, thereby solving problems such as limited appearance, insufficient durability, difficulty in maintaining lubrication performance over a long period, and poor adhesion of existing coatings. By integrating photothermal conversion, low surface energy modification, and cohesive self-lubricating components, and optimizing the coating structure and interface bonding, passive heating to delay icing under sunlight and natural de-icing relying on low surface energy and lubricant are achieved in the absence of sunlight, thus significantly improving the operational safety and economy of wind turbine blades in cold regions.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions: A composite photothermal self-lubricating superhydrophobic anti-icing coating comprises the following components by weight: 0.3-0.6 parts of surface-treated multi-walled carbon nanotubes; 0.2-0.4 parts of surface-treated nano-zirconia; 0.06-0.09 parts of fluorinated silane coupling agent; 0.8-1.4 parts of acrylate monomer mixture; 0.01-0.02 parts of initiator; and 0.3-0.45 parts of isocyanate curing agent.

[0007] Optionally, the surface-treated multi-walled carbon nanotubes and nano-zirconia are hydrophobically treated by hydroxylation and silanization.

[0008] Optionally, the fluorinated silane coupling agent is perfluorooctyltrichlorosilane; the initiator is azobisisobutyronitrile.

[0009] Optionally, the acrylate monomer mixture comprises a first acrylate monomer, a second acrylate monomer, a third acrylate monomer, and a fourth acrylate monomer, wherein the first acrylate monomer is selected from one or more of methyl methacrylate, butyl acrylate, ethylhexyl acrylate, and tert-butyl acrylate; the second acrylate monomer is selected from one or more of hydroxyethyl acrylate and hydroxypropyl acrylate; the third acrylate monomer is a monoacrylate-terminated polydimethylsiloxane; and the fourth acrylate monomer is selected from one or more of 3-trimethoxysilanepropyl acrylate and methacryloxypropyltriethoxysilane.

[0010] Optionally, the isocyanate curing agent is one or more of hexamethylene diisocyanate, isophorone diisocyanate, and polyhexamethylene diisocyanate trimer.

[0011] This invention also provides a method for preparing the composite photothermal self-lubricating superhydrophobic anti-icing coating as described above, comprising: hydroxylating multi-walled carbon nanotubes and nano-zirconia; silanizing and hydrophobizing the hydroxylated multi-walled carbon nanotubes and nano-zirconia using a fluorinated silane coupling agent to obtain hydrophobic multi-walled carbon nanotubes and hydrophobic nano-zirconia; polymerizing an acrylate monomer mixture in the presence of an initiator to obtain a polymer matrix; mixing the hydrophobic multi-walled carbon nanotubes, hydrophobic nano-zirconia, and polymer matrix with an isocyanate curing agent, coating the mixture onto the surface of a substrate, and curing the coating to obtain the coating.

[0012] Optionally, the hydroxylation treatment involves adding multi-walled carbon nanotubes and nano-zirconia to a mixed acid solution of sulfuric acid and nitric acid, and refluxing at 70-90°C for 3-6 hours.

[0013] Optionally, the silanization hydrophobic treatment involves adding a fluorinated silane coupling agent and an alkaline catalyst to an alcohol-water mixed solvent, and reacting the hydroxylated multi-walled carbon nanotubes and nano-zirconia with them at room temperature for 24-36 hours.

[0014] Optionally, the polymerization reaction is carried out at 75~85°C for 2~4 hours; the curing is carried out at room temperature for 48~72 hours.

[0015] This invention also provides an application of the composite photothermal self-lubricating superhydrophobic anti-icing coating described above in the anti-icing protection of wind turbine blade surfaces.

[0016] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages: 1. In the anti-icing coating of this invention, multi-walled carbon nanotubes primarily contribute to photothermal conversion performance. Under illumination, they effectively absorb solar radiation and convert it into heat energy, passively raising the surface temperature of the coating and thus delaying or inhibiting the formation of ice crystals. Nano-zirconia primarily enhances the mechanical wear resistance of the coating, providing high hardness and resistance to the erosion of external particles such as wind, sand, and raindrops, protecting the micro-nano structure of the coating surface and maintaining long-term hydrophobicity. Both fillers undergo surface treatment to improve their dispersibility in the polymer matrix and impart hydrophobic properties. A fluorosilane coupling agent is used to hydrophobically modify the fillers, and its perfluoroalkyl chains can significantly reduce surface energy. The acrylate monomer mixture, after polymerization, forms the polymer matrix of the coating. This matrix not only provides film-forming properties and adhesion to the substrate but also introduces specific monomers to give the coating cohesive self-lubricating properties. An initiator is used to initiate monomer polymerization, and the isocyanate curing agent reacts with the active groups in the polymer matrix to form a cross-linked network, thereby improving the mechanical strength, adhesion, and durability of the coating. The components work synergistically in the above proportions. The photothermal filler provides active anti-icing capability, the wear-resistant filler protects structural integrity, and the low surface energy treatment and self-lubricating polymer matrix together ensure extremely low ice adhesion. Cross-linking curing ensures the service life of the coating in harsh environments. Together, they solve the technical problems of traditional coatings, such as single function, insufficient durability, reliance on external energy or easy loss of lubricant. They achieve passive heating to delay icing under sunlight and natural de-icing by relying on low surface energy and lubricant when there is no sunlight, thereby significantly improving the operational safety and economy of wind turbine blades in cold regions.

[0017] 2. This invention integrates an absorbing material with strong photothermal effect with a low surface energy self-lubricating superhydrophobic material on the same micro-nano structure surface. It can not only rapidly heat up and actively delay the icing process during the day with the help of natural light, but also maintain extremely low ice adhesion at night or in the absence of light due to the low adhesion properties of the self-lubricating superhydrophobic material. This achieves a truly all-weather, energy-free ice suppression and de-icing function, which is significantly different from traditional single-function or external energy-dependent anti-icing solutions.

[0018] 3. The surface micro-nano structure is finely designed so that water droplets can interact with the substrate with a very small contact area and roll off quickly after contact. At the same time, the liquid-like molecular layer forms a stable lubricating interface on the surface of the micro-nano structure, which destroys the interfacial bonding force in the early stage of ice crystal formation, greatly reducing ice adhesion and improving the operational safety of wind turbine blades in low-temperature environments.

[0019] 4. By introducing liquid-like molecular chain segments into the polymer matrix, this invention avoids the performance degradation caused by lubricant evaporation and migration in conventional SLIPS (liquid-slip surface), and can maintain superhydrophobic and low ice adhesion properties for a long time even under high wind speed, high particle impact or ultraviolet irradiation conditions, thus greatly improving service life.

[0020] 5. The coating and the substrate material are treated with a multifunctional cross-linking process, which significantly improves the adhesion and mechanical strength, so that it can still adhere stably to the surface of the wind turbine blades after long-term wind and sand erosion, rain and snow impact, and ultraviolet aging, maintaining the synergistic effect of photothermal and lubrication, and achieving multiple protections and long-term stable operation.

[0021] Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In addition, the dimensions or spacing between the components are exaggerated to show the position of each component, and the schematic diagrams are for illustrative purposes only.

[0023] Figure 1 These are scanning electron microscope images of the coating surface provided in the embodiments of the present invention; Figure 2 This is a schematic diagram of the contact angle / sliding angle of the coating provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the photothermal conversion efficiency and temperature rise curve of the coating provided in the embodiment of the present invention; Figure 4 This is a schematic diagram comparing the de-icing power of the coatings provided in the embodiments of the present invention; Figure 5 This is a schematic diagram illustrating the change in hydrophobic properties of the coating during wear resistance testing, provided in an embodiment of the present invention. Figure 6 This is a schematic diagram illustrating the change in hydrophobic properties of the ice coating before and after UV resistance testing, provided in an embodiment of the present invention. Detailed Implementation It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0024] A composite photothermal self-lubricating superhydrophobic anti-icing coating comprises the following components by weight: 0.3-0.6 parts of surface-treated multi-walled carbon nanotubes; 0.2-0.4 parts of surface-treated nano-zirconia; 0.06-0.09 parts of fluorinated silane coupling agent; 0.8-1.4 parts of acrylate monomer mixture; 0.01-0.02 parts of initiator; and 0.3-0.45 parts of isocyanate curing agent.

[0025] Multi-walled carbon nanotubes and nano-zirconia are used as functional fillers to synergistically construct a multi-level micro / nano structure in the coating. Multi-walled carbon nanotubes possess excellent light absorption properties, enabling them to convert solar energy into heat, thus raising the surface temperature of the coating. In addition to a certain photothermal auxiliary effect, nano-zirconia exhibits high hardness, enhancing the mechanical strength and wear resistance of the coating. Fluorinated silane coupling agents are used to treat the filler surface, introducing perfluoroalkyl segments into the micro / nano structure surface and reducing surface free energy. An acrylate monomer mixture is polymerized to form a polymer matrix, which not only acts as a binder to fix various fillers to the substrate surface but also introduces self-lubricating components through specific monomer design. An initiator is used to initiate the free radical polymerization reaction of the acrylate monomers. An isocyanate curing agent undergoes a cross-linking reaction with the active groups in the polymer matrix, forming a three-dimensional network structure that improves the overall cohesion and adhesion of the coating. When the components are formulated in the specified weight proportions, the photothermal conversion function and the superhydrophobic self-lubricating function are balanced. This allows the coating to utilize sunlight to raise the temperature and delay icing, while also reducing ice adhesion through low surface energy and lubrication in the absence of sunlight, thus solving the problem of single-function coatings being unable to achieve all-weather ice suppression. Simultaneously, this formulation avoids the lubricant loss defects present in traditional liquid-lubricated surfaces, fixing the lubricating components within the polymer network through chemical bonding, thereby improving the long-term stability of the coating.

[0026] The surface-treated multi-walled carbon nanotubes and nano-zirconia undergo hydroxylation and silanization hydrophobic treatment to ensure the stability of the hydrophobic modified layer and avoid the easy loss of physically adsorbed modifiers. The filler treated in this way not only possesses hydrophobicity itself but also exhibits better compatibility and uniform dispersion with the hydrophobic polymer matrix in the coating.

[0027] The fluorinated silane coupling agent is perfluorooctyltrichlorosilane, which imparts hydrophobicity to the coating surface; the initiator is azobisisobutyronitrile, which can effectively initiate monomer polymerization to form a polymer matrix.

[0028] The acrylate monomer mixture comprises a first acrylate monomer, a second acrylate monomer, a third acrylate monomer, and a fourth acrylate monomer. The first acrylate monomer is selected from one or more of methyl methacrylate, butyl acrylate, ethylhexyl acrylate, and tert-butyl acrylate. The second acrylate monomer is selected from one or more of hydroxyethyl acrylate and hydroxypropyl acrylate. The third acrylate monomer is a monoacrylate-terminated polydimethylsiloxane. The fourth acrylate monomer is selected from one or more of 3-trimethoxysilanepropyl acrylate and methacryloxypropyltriethoxysilane.

[0029] The mixture contains four types of monomers with different functions, which are copolymerized to form a multifunctional polymer matrix that integrates multiple functions such as film formation, crosslinking, self-lubrication and enhanced adhesion. It is the basis for the coating to achieve long-lasting and stable anti-icing performance.

[0030] The isocyanate curing agent is one or more of hexamethylene diisocyanate, isophorone diisocyanate, and polyhexamethylene diisocyanate trimer, which can undergo addition polymerization with hydroxyl groups on the polymer matrix to form a crosslinked network of polyurethane or polyurea-urethane structure, thereby improving the mechanical strength, wear resistance, solvent resistance and adhesion to the substrate of the coating.

[0031] The coating, by weight, specifically comprises: 0.3-0.6 parts multi-walled carbon nanotubes, 0.2-0.4 parts nano-zirconia, 0.06-0.09 parts perfluorooctyltrichlorosilane, 0.5-0.8 parts of a first acrylate monomer (one or more of methyl methacrylate, butyl acrylate, ethylhexyl acrylate, and tert-butyl acrylate), 0.2-0.3 parts of a second acrylate monomer (one or more of hydroxyethyl acrylate and hydroxypropyl acrylate), and 0.05-0.6 parts of a third acrylate monomer (monoacrylate-terminated polydimethylsiloxane). 0.15 parts, 0.05-0.15 parts of the fourth acrylate monomer (one or more of 3-trimethoxysilane propyl acrylate and methacryloxypropyltriethoxysilane), 0.01-0.02 parts of azobisisobutyronitrile, 0.3-0.45 parts of isocyanate curing agent (one or more of hexamethylene diisocyanate, isophorone diisocyanate, and polyhexamethylene diisocyanate trimer), and 0.005-0.02 parts of triethylamine, wherein the solvents include deionized water, ethanol, dimethylformamide, ethyl acetate, and butyl acetate.

[0032] A method for preparing a composite photothermal self-lubricating superhydrophobic anti-icing coating includes: hydroxylating multi-walled carbon nanotubes and nano-zirconia; silanizing and hydrophobizing the hydroxylated multi-walled carbon nanotubes and nano-zirconia using a fluorinated silane coupling agent to obtain hydrophobic multi-walled carbon nanotubes and hydrophobic nano-zirconia; polymerizing an acrylate monomer mixture in the presence of an initiator to obtain a polymer matrix; mixing the hydrophobic multi-walled carbon nanotubes, hydrophobic nano-zirconia, and polymer matrix with an isocyanate curing agent, coating the mixture onto the surface of a substrate, and curing the coating to obtain the coating.

[0033] Hydroxylation treatment of multi-walled carbon nanotubes and nano-zirconia: Multi-walled carbon nanotubes and nano-zirconia are oxidized by mixed acid to generate reactive functional groups such as carboxyl / hydroxyl groups on their surface, preparing an active surface for subsequent hydrophobic grafting.

[0034] Hydrophobic treatment of multi-walled carbon nanotubes and nano-zirconia: After hydrolysis of fluorinated silane coupling agent to generate silanol groups, they are then grafted with pre-hydroxylated multi-walled carbon nanotubes and nano-zirconia to perform hydrophobic treatment, thereby obtaining functional fillers with durable hydrophobicity.

[0035] Synthesis of self-lubricating hydroxy acrylic polymer matrix: The first to fourth acrylate monomers were synthesized by free radical polymerization to form a self-lubricating hydroxy acrylic polymer matrix.

[0036] Preparation of composite photothermal self-lubricating superhydrophobic anti-icing coating: After mixing and dispersing a self-lubricating hydroxy acrylic polymer matrix with hydrophobically treated multi-walled carbon nanotubes and nano-zirconia, a polyfunctional isocyanate was used as a curing agent and applied to glass fiber reinforced plastic by spraying. After curing at room temperature, a composite photothermal self-lubricating superhydrophobic anti-icing coating was obtained.

[0037] Specific steps for coating preparation: Step (1): Add 0.3-0.6 parts of multi-walled carbon nanotubes and 0.2-0.4 parts of nano-zirconia to a pre-prepared acid solution of 20-40 parts, wherein the acid solution is prepared according to a sulfuric acid to nitric acid ratio of 3:1. After ultrasonic dispersion, reflux the reaction at 70-90℃ for 3-6 hours. After the reaction is completed, wait for the system temperature to return to room temperature, then transfer the system to an ice-water bath and slowly add deionized water, washing repeatedly with deionized water until the pH is approximately 6.5-7. Then dry the product in a vacuum drying oven at 75-80℃ for 12-24 hours to finally obtain hydroxylated multi-walled carbon nanotubes and nano-zirconia.

[0038] A mixed acid solution with a sulfuric acid to nitric acid ratio of 3:1 can effectively introduce oxygen-containing functional groups onto the surfaces of carbon nanotubes and zirconium oxide. The reaction temperature should be 70–90 °C and the reaction time 3–6 hours. Too low a temperature or too short a time may result in insufficient hydroxylation, affecting subsequent grafting; too high a temperature or too long a time may lead to excessive destruction of the carbon nanotube structure or agglomeration of nanoparticles.

[0039] Step (2): Weigh 0.4-0.6 parts of hydroxylated multi-walled carbon nanotubes and 0.1-0.2 parts of hydroxylated nano-zirconia under dry and inert conditions and place them in a three-necked flask. Add them to 80-120 parts of ethanol and ultrasonically disperse for 5-15 minutes. Add 10-20 parts of deionized water to the system and continue ultrasonic stirring to mix the system evenly. Slowly add 0.06-0.09 parts of perfluorooctyltrichlorosilane and a small amount of triethylamine as a basic catalyst (0.005-0.02 parts), and then stir at room temperature for 24-36 hours. After the reaction, wash repeatedly with ethanol and dimethylformamide solvent at least 3-5 times to remove physically adsorbed free silane and byproducts. Dry and cure the washed product in an oven at 80-120℃ for 10-12 hours to promote Si-O-Si condensation and grafting, improve stability, and finally obtain hydrophobic multi-walled carbon nanotubes and nano-zirconia.

[0040] The addition of an alkaline catalyst (such as triethylamine) catalyzes the hydrolysis of silanes and their condensation reaction with hydroxyl groups on the filler surface. A reaction time of 24–36 hours at room temperature ensures the grafting reaction proceeds fully. After the reaction, the cells are repeatedly washed with solvent to remove physically adsorbed unreacted silanes and byproducts, ensuring the purity and strength of the grafted layer. Finally, drying and curing are performed to promote the condensation crosslinking of the silane layer itself, thereby improving its stability.

[0041] Step (3) add 0.5-0.8 parts of the first acrylate monomer (one or more of methyl methacrylate, butyl acrylate, ethylhexyl acrylate and tert-butyl acrylate), 0.2-0.3 parts of the second acrylate monomer (one or more of hydroxyethyl acrylate and hydroxypropyl acrylate), 0.05-0.15 parts of the third acrylate monomer (monoacrylate-terminated polydimethylsiloxane), and 0.05-0.15 parts of the fourth acrylate monomer (one or more of 3-trimethoxysilane propyl acrylate and methacryloyloxypropyltriethoxysilane) to 30-50 parts of solvent (one of ethyl acetate, butyl acetate, propylene glycol methyl ether acetate, N,N-dimethylformamide and N,N-dimethylacetamide). After thorough stirring, the system was refluxed at 75-85°C with stirring. During the process, 0.01-0.02 parts of azobisisobutyronitrile were slowly added. The polymerization reaction was continued for 2-4 hours while maintaining the temperature. The solvent was removed by rotary evaporation under negative pressure to obtain a self-lubricating hydroxyl acrylic polymer matrix.

[0042] The polymerization reaction temperature of 75~85℃ matches the decomposition temperature of the initiator azobisisobutyronitrile, which can ensure uniform decomposition of the initiator and stable polymerization of monomers. The reaction time of 2~4 hours is sufficient to achieve a high monomer conversion rate.

[0043] Step (4) Add 0.3~0.5 parts of hydrophobic multi-walled carbon nanotubes, 0.05~0.15 parts of hydrophobic nano-zirconia, and 0.5~1.5 parts of self-lubricating hydroxyl acrylic polymer matrix to 8~12 parts of solvent (one of ethyl acetate and butyl acetate), and add 0.3~0.45 parts of isocyanate curing agent (one or more of hexamethylene diisocyanate, isophorone diisocyanate, and polyhexamethylene diisocyanate trimer). After stirring and mixing for 30~45 minutes, spray it onto the substrate and cure it at room temperature for 48~72 hours to obtain a composite photothermal self-lubricating superhydrophobic anti-icing coating.

[0044] Room temperature curing facilitates the gradual reaction between isocyanate and hydroxyl groups, forming a uniform cross-linked network. This avoids internal stress or bubbles that may be caused by rapid curing at high temperatures, allowing the coating to flow fully and adhere tightly to the substrate.

[0045] The coating prepared by the above method combines multiple functions, including photothermal active anti-icing, superhydrophobic passive anti-icing, and self-lubrication to reduce ice adhesion. It also exhibits long-lasting durability, making it ideal for handling the complex and harsh environments faced by wind turbine blades, such as low temperatures, high humidity, strong winds, ultraviolet radiation, and particulate erosion. Applying this coating to the blade surface can improve the operational safety and reliability of the blades in icy and cold weather without requiring external energy input, and reduce de-icing maintenance costs.

[0046] Example 1 Step (1) 0.5 parts of multi-walled carbon nanotubes and 0.3 parts of nano-zirconia were added to a pre-prepared acid solution of 30 parts, wherein the acid solution was prepared according to a sulfuric acid to nitric acid ratio of 3:1. After ultrasonic dispersion, the mixture was refluxed at 80°C for 4 hours. After the reaction was completed, the system was transferred to an ice-water bath and deionized water was slowly added. The mixture was repeatedly washed with deionized water until the pH was approximately 6.5-7. The product was then dried in a vacuum drying oven at 80°C for 16 hours to finally obtain hydroxylated multi-walled carbon nanotubes and nano-zirconia.

[0047] Step (2): Weigh 0.5 parts of hydroxylated multi-walled carbon nanotubes and 0.15 parts of hydroxylated nano-zirconia under dry and inert conditions and place them in a three-necked flask. Add them to 100 parts of ethanol and ultrasonically disperse for 10 minutes. Add 15 parts of deionized water to the system and continue ultrasonic stirring to mix the system evenly. Slowly add 0.08 parts of perfluorooctyltrichlorosilane and a small amount of triethylamine as a basic catalyst, and then stir at room temperature for 24 hours. After the reaction, wash repeatedly with ethanol and dimethylformamide solvent at least 3-5 times to remove physically adsorbed free silane and byproducts. Dry the washed product in an oven at 100°C and cure for 12 hours to promote Si-O-Si condensation and grafting, improve stability, and finally obtain hydrophobic multi-walled carbon nanotubes and nano-zirconia.

[0048] Step (3) 0.6 parts of the first acrylate monomer, 0.25 parts of the second acrylate monomer, 0.1 parts of the third acrylate monomer, and 0.1 parts of the fourth acrylate monomer were added to 40 parts of solvent. After thorough stirring, the system was refluxed at 80°C with stirring. During the process, 0.015 parts of azobisisobutyronitrile were slowly added. The polymerization reaction was continued for 4 hours while maintaining the temperature. The solvent was then removed by rotary evaporation under negative pressure to obtain a self-lubricating hydroxyl acrylic polymer matrix.

[0049] Step (4) Add 0.4 parts of hydrophobic multi-walled carbon nanotubes, 0.1 parts of hydrophobic nano-zirconia, and 1 part of self-lubricating hydroxyl acrylic polymer matrix to 10 parts of solvent. After stirring and mixing for 30 minutes, spray it onto the substrate and cure it at room temperature for 72 hours to obtain a composite photothermal self-lubricating superhydrophobic anti-icing coating.

[0050] The coatings prepared in the embodiments and comparative examples of this invention were subjected to performance tests as follows: Contact Angle / Slip Angle Measurement: The contact angle of water droplets on the coating surface was measured using a KRüSS DSA25S optical contact angle analysis system. For contact angle measurement in a static state, a water droplet (~5 μL) was first added to the sample surface using a motor-controlled syringe. When the droplet stabilized, a side image was captured using a camera, and the static contact angle of the water droplet on the coating surface was obtained by fitting and calculating using software. For slip angle measurement in a dynamic state, a water droplet (~10 μL) was pre-added to the coating surface, and then the sample platform was rotated using a motor. The real-time rotation angle could be read in the software. When the liquid just began to slide, the motor rotation angle was recorded, which is the slip angle.

[0051] Coating photothermal performance testing: Calculating the photothermal conversion efficiency of the coating typically involves joint testing of both photothermal and electric heating modules, deriving the actual efficiency through a heat balance equation. The specific method is as follows: An electro-optic equivalent measurement method is used, simulating the photothermal heating process through electric heating. In the electric heating module, resistance heating is employed and temperature changes are monitored; the comprehensive heat dissipation coefficient is obtained through linear fitting. In the photothermal module, a 1 kW / m²... 2 The light source simulates heating with 1 unit of sunlight and records the temperature change curve. The photothermal conversion efficiency is derived by combining the heat balance equation.

[0052] Coating de-icing performance test: 1. De-icing performance test under sunlight: A 1 cm³ volume of... 3 Ice blocks were placed on the sample surface and frozen overnight in a -30°C freezer. The sample was then placed outdoors in sunlight (outdoor temperature below 0°C). The ice blocks were pushed using a thrust meter probe, and the peak force required to push the ice blocks was recorded. The peak force value was divided by the contact area to obtain the adhesion force of the ice blocks on the sample surface (i.e., de-icing force). 2. De-icing performance test under no-light conditions: Except for sunlight, the other test conditions and methods were the same as those under sunlight conditions.

[0053] Coating Adhesion Test: The coating adhesion was tested according to ASTM D3359. All test samples were cross-cut at 1 mm intervals using a QHF cross-cutting tool, and then subjected to 3M... TM 600 tape was firmly adhered to the marked area. A 2 kg weight was then placed on the tape and slid down to ensure complete contact between the tape and the test area. After 90 seconds of stillness, the tape was quickly pulled off vertically (90°). Two tests were performed on the same area, and the remaining coating on the substrate was observed to assess adhesion. According to the standard, adhesion is rated 5B when the coating peeling is approximately 0%; 4B when the peeling is less than 5%; 3B when the peeling is less than 15%; 2B when the peeling is less than 35%; 1B when the peeling is less than 65%; and 0B when the peeling is greater than 65%.

[0054] Taber Abrasion Test of Coating: The abrasion resistance of the coating was tested according to ASTM D4060. All test samples were sprayed onto a substrate suitable for mounting on the rotating platform of the Taber abrasion tester and fixed to the platform using vacuum adsorption. A CS-10 grinding wheel was used, and a specified 500 g load was applied to the wheel. The equipment was then set to the specified rotation speed for the abrasion test. During the test, abrasive debris was periodically cleaned with a soft brush or vacuum cleaner to avoid secondary wear. After the test, the mass loss of the sample was accurately measured using a balance, and the abrasion resistance of the coating was evaluated by the change in water contact angle / slip angle.

[0055] UV Resistance Testing of Coatings: The UV resistance of the coatings was tested according to ASTM G154. Before testing, the coated samples were fixed on the sample rack in a UV aging chamber. The UV-A or UV-B lamp light source, irradiance (0.89 W / m²), temperature (60 ℃), and condensation humidity cycling conditions were set according to the standard requirements, and the samples were continuously exposed for a certain period of time (8 hours of UV exposure + 4 hours of condensation constitutes one cycle). After the exposure, the color values ​​of the sample surface before and after the test were measured using a spectrophotometer, and the color difference was calculated.

[0056] Figure 1 This is a scanning electron microscope (SEM) image of the surface of a composite photothermal self-lubricating superhydrophobic anti-icing coating. The SEM image shows that the coating consists of a multi-level micro / nano structure synergistically constructed by multi-walled carbon nanotubes and nano-zirconia, which can form a stable air film on the surface, significantly reducing the solid-liquid contact area, inhibiting ice nucleation, and reducing ice adhesion.

[0057] Figure 2 Optical photographs showing the initial water contact angle / slip angle of the surface of the composite photothermal self-lubricating superhydrophobic anti-icing coating. Water droplets on the coating surface exhibit excellent superhydrophobicity, with a contact angle of 157.62° and a slip angle of only 1.58°.

[0058] Figure 3 The photothermal conversion efficiency and temperature rise curves of the composite photothermal self-lubricating superhydrophobic anti-icing coating are shown. Photothermal conversion performance tests indicate that the photothermal conversion efficiency of Example 1 is 76.32%, and the temperature rises from [value missing] to [value missing] within 10 minutes under outdoor sunlight conditions. The temperature rose from 12.56°C to 9.21°C.

[0059] Figure 4 This study compares the de-icing force of a composite photothermal self-lubricating superhydrophobic anti-icing coating under sunlight and darkness conditions. The test results show that the ice adhesion force is only 5.8 kPa under sunlight conditions, while it is 8.1 kPa under darkness conditions.

[0060] Figure 5To test the hydrophobic properties of the composite photothermal self-lubricating superhydrophobic anti-icing coating during wear resistance testing, after 300 revolutions of Taber wear under a 500g load, the water contact angle remained at 151.06° and the sliding angle at 4.52°, maintaining the superhydrophobic characteristics.

[0061] Figure 6 The changes in hydrophobic properties of the composite photothermal self-lubricating superhydrophobic anti-icing coating before and after UV resistance testing were shown. After 100 hours of UV irradiation, the water contact angle was 150.82° and the sliding angle was 5.29°, indicating that the coating still has stable superhydrophobicity and photothermal anti-icing properties under long-term environmental conditions.

[0062] Example 2 Step (1) 0.3 parts of multi-walled carbon nanotubes and 0.2 parts of nano-zirconia were added to a pre-prepared acid solution of 30 parts, wherein the acid solution was prepared according to a sulfuric acid to nitric acid ratio of 3:1. After ultrasonic dispersion, the mixture was refluxed at 80°C for 4 hours. After the reaction was completed, the system temperature was allowed to return to room temperature, and then the system was transferred to an ice-water bath and deionized water was slowly added. The mixture was repeatedly washed with deionized water until the pH was approximately 6.5-7. The product was then dried in a vacuum drying oven at 80°C for 16 hours to finally obtain hydroxylated multi-walled carbon nanotubes and nano-zirconia.

[0063] Step (2): Weigh 0.4 parts of hydroxylated multi-walled carbon nanotubes and 0.1 parts of hydroxylated nano-zirconia under dry and inert conditions and place them in a three-necked flask. Add them to 100 parts of ethanol and ultrasonically disperse for 10 minutes. Add 15 parts of deionized water to the system and continue ultrasonic stirring to mix the system evenly. Slowly add 0.06 parts of perfluorooctyltrichlorosilane and a small amount of triethylamine as a basic catalyst, and then stir at room temperature for 24 hours. After the reaction, wash repeatedly with ethanol and dimethylformamide solvent at least 3-5 times to remove physically adsorbed free silane and byproducts. Dry the washed product in an oven at 100°C and cure for 12 hours to promote Si-O-Si condensation and grafting, improve stability, and finally obtain hydrophobic multi-walled carbon nanotubes and nano-zirconia.

[0064] Step (3) 0.6 parts of the first acrylate monomer, 0.25 parts of the second acrylate monomer, 0.1 parts of the third acrylate monomer, and 0.1 parts of the fourth acrylate monomer were added to 40 parts of solvent. After thorough stirring, the system was refluxed at 80°C with stirring. During the process, 0.015 parts of azobisisobutyronitrile were slowly added. The polymerization reaction was continued for 4 hours while maintaining the temperature. The solvent was then removed by rotary evaporation under negative pressure to obtain a self-lubricating hydroxyl acrylic polymer matrix.

[0065] Step (4) Add 0.3 parts of hydrophobic multi-walled carbon nanotubes, 0.05 parts of hydrophobic nano-zirconia, and 1.5 parts of self-lubricating hydroxyl acrylic polymer matrix to 10 parts of solvent. After stirring and mixing for 30 minutes, spray the mixture onto the substrate and cure it at room temperature for 72 hours to obtain Example 2.

[0066] As shown in Table 1, the coating obtained in this embodiment has a water contact angle of 152.18° and a waterslip angle of 2.49°, which is a decrease in superhydrophobicity compared to Example 1. This is mainly because the reduced amount of multi-walled carbon nanotubes and nano-zirconia leads to the micro-nano structure being partially covered by the polymer matrix. However, the coating still meets the superhydrophobic standard. The photothermal conversion efficiency is 52.13%, which is due to the lower content of multi-walled carbon nanotubes compared to Example 1. The ice adhesion under sunlight and no sunlight conditions is 6.4 and 8.9 kPa, respectively, which is relatively low. However, the adhesion is increased compared to Example 1 due to the loss of anti-wetting properties. The adhesion level reaches 4B, and the color difference value after UV aging test is within an acceptable range.

[0067] Example 3 Step (1) 0.6 parts of multi-walled carbon nanotubes and 0.4 parts of nano-zirconia were added to a pre-prepared acid solution of 30 parts, wherein the acid solution was prepared according to a sulfuric acid to nitric acid ratio of 3:1. After ultrasonic dispersion, the mixture was refluxed at 80°C for 4 hours. After the reaction was completed, the system temperature was allowed to return to room temperature, and then the system was transferred to an ice-water bath and deionized water was slowly added. The mixture was repeatedly washed with deionized water until the pH was approximately 6.5-7. The product was then dried in a vacuum drying oven at 80°C for 16 hours to finally obtain hydroxylated multi-walled carbon nanotubes and nano-zirconia.

[0068] Step (2): Weigh 0.6 parts of hydroxylated multi-walled carbon nanotubes and 0.2 parts of hydroxylated nano-zirconia under dry and inert conditions and place them in a three-necked flask. Add them to 100 parts of ethanol and ultrasonically disperse for 10 minutes. Add 15 parts of deionized water to the system and continue ultrasonic stirring to mix the system evenly. Slowly add 0.09 parts of perfluorooctyltrichlorosilane and a small amount of triethylamine as a basic catalyst, and then stir at room temperature for 24 hours. After the reaction, wash repeatedly with ethanol and dimethylformamide solvent at least 3-5 times to remove physically adsorbed free silane and byproducts. Dry the washed product in an oven at 100°C and cure for 12 hours to promote Si-O-Si condensation and grafting, improve stability, and finally obtain hydrophobic multi-walled carbon nanotubes and nano-zirconia.

[0069] Step (3) 0.6 parts of the first acrylate monomer, 0.25 parts of the second acrylate monomer, 0.1 parts of the third acrylate monomer, and 0.1 parts of the fourth acrylate monomer were added to 40 parts of solvent. After thorough stirring, the system was refluxed at 80°C with stirring. During the process, 0.015 parts of azobisisobutyronitrile were slowly added. The polymerization reaction was continued for 4 hours while maintaining the temperature. The solvent was then removed by rotary evaporation under negative pressure to obtain a self-lubricating hydroxyl acrylic polymer matrix.

[0070] Step (4) Add 0.5 parts of hydrophobic multi-walled carbon nanotubes, 0.15 parts of hydrophobic nano-zirconia, and 0.5 parts of self-lubricating hydroxyl acrylic polymer matrix to 10 parts of solvent. After stirring and mixing for 30 minutes, spray the mixture onto the substrate and cure it at room temperature for 72 hours to obtain Example 3.

[0071] As shown in Table 1, the coating obtained in this embodiment has a water contact angle of 163.37° and a waterslip angle of 1.17°, which is an improvement in superhydrophobic performance compared to Example 1. This is mainly due to the increased amount of multi-walled carbon nanotubes and nano-zirconia, resulting in a richer exposure of micro- and nano-rough structures. The photothermal conversion efficiency is 77.18%, which is due to the higher content of multi-walled carbon nanotubes compared to Example 1. The ice adhesion under sunlight and no sunlight conditions is 5.5 and 11.8 kPa, respectively. Under sunlight conditions, the higher content of carbon nanotubes provides more heat, causing the ice to melt faster; while under no sunlight conditions, due to the increase in micro- and nano-rough structures, some ice is embedded in the structure, resulting in increased de-icing force. The adhesion level can only reach the 3B level, and the color difference value after UV aging test is within the acceptable range.

[0072] Comparative Example 1 Step (1) 0.5 parts of multi-walled carbon nanotubes and 0.3 parts of nano-zirconia were added to a pre-prepared acid solution of 30 parts, wherein the acid solution was prepared according to a sulfuric acid to nitric acid ratio of 3:1. After ultrasonic dispersion, the mixture was refluxed at 80°C for 4 hours. After the reaction was completed, the system was transferred to an ice-water bath and deionized water was slowly added. The mixture was repeatedly washed with deionized water until the pH was approximately 6.5-7. The product was then dried in a vacuum drying oven at 80°C for 16 hours to finally obtain hydroxylated multi-walled carbon nanotubes and nano-zirconia.

[0073] Step (2): Weigh 0.5 parts of hydroxylated multi-walled carbon nanotubes and 0.15 parts of hydroxylated nano-zirconia under dry and inert conditions and place them in a three-necked flask. Add them to 100 parts of ethanol and ultrasonically disperse for 10 minutes. Add 15 parts of deionized water to the system and continue ultrasonic stirring to mix the system evenly. Slowly add 0.08 parts of perfluorooctyltrichlorosilane and a small amount of triethylamine as a basic catalyst, and then stir at room temperature for 24 hours. After the reaction, wash repeatedly with ethanol and dimethylformamide solvent at least 3-5 times to remove physically adsorbed free silane and byproducts. Dry the washed product in an oven at 100°C and cure for 12 hours to promote Si-O-Si condensation and grafting, improve stability, and finally obtain hydrophobic multi-walled carbon nanotubes and nano-zirconia.

[0074] Step (3) 0.6 parts of the first acrylate monomer, 0.25 parts of the second acrylate monomer, 0 parts of the third acrylate monomer, and 0.1 parts of the fourth acrylate monomer were added to 40 parts of solvent. After thorough stirring, the system was refluxed at 80°C with stirring. During the process, 0.015 parts of azobisisobutyronitrile were slowly added. The polymerization reaction was continued for 4 hours while maintaining the temperature. The solvent was removed by rotary evaporation under negative pressure to obtain a self-lubricating hydroxyl acrylic polymer matrix.

[0075] Step (4) Add 0.4 parts of hydrophobic multi-walled carbon nanotubes, 0.1 parts of hydrophobic nano-zirconia, and 1 part of self-lubricating hydroxyl acrylic polymer matrix to 10 parts of solvent. After stirring and mixing for 30 minutes, spray the mixture onto the substrate and cure it at room temperature for 72 hours to obtain Comparative Example 1.

[0076] The coating prepared in this comparative example retains only superhydrophobic properties but loses self-lubricating properties because no third acrylate monomer was added in step (3). This results in a significant increase in de-icing power under both sunlight and non-sunlight conditions. Other indicators are detailed in Table 1 below.

[0077] Comparative Example 2 Step (1) 0.5 parts of multi-walled carbon nanotubes and 0 parts of nano-zirconia were added to a pre-prepared acid solution of 30 parts, wherein the acid solution was prepared according to a sulfuric acid to nitric acid ratio of 3:1. After ultrasonic dispersion, the mixture was refluxed at 80°C for 4 hours. After the reaction was completed, the system temperature was allowed to return to room temperature, and then the system was transferred to an ice-water bath and deionized water was slowly added. The mixture was repeatedly washed with deionized water until the pH was approximately 6.5-7. The product was then dried in a vacuum drying oven at 80°C for 16 hours to finally obtain hydroxylated multi-walled carbon nanotubes and nano-zirconia.

[0078] Step (2): Weigh 0.5 parts of hydroxylated multi-walled carbon nanotubes and 0 parts of hydroxylated nano-zirconia under dry and inert conditions and place them in a three-necked flask. Add them to 100 parts of ethanol and ultrasonically disperse for 10 minutes. Add 15 parts of deionized water to the system and continue ultrasonic stirring to mix the system evenly. Slowly add 0.08 parts of perfluorooctyltrichlorosilane and a small amount of triethylamine as a basic catalyst, and then stir at room temperature for 24 hours. After the reaction, wash repeatedly with ethanol and dimethylformamide solvent at least 3-5 times to remove physically adsorbed free silane and byproducts. Dry the washed product in an oven at 100°C and cure for 12 hours to promote Si-O-Si condensation and grafting, improve stability, and finally obtain hydrophobic multi-walled carbon nanotubes and nano-zirconia.

[0079] Step (3) 0.6 parts of the first acrylate monomer, 0.25 parts of the second acrylate monomer, 0.1 parts of the third acrylate monomer, and 0.1 parts of the fourth acrylate monomer were added to 40 parts of solvent. After thorough stirring, the system was refluxed at 80°C with stirring. During the process, 0.015 parts of azobisisobutyronitrile were slowly added. The polymerization reaction was continued for 4 hours while maintaining the temperature. The solvent was then removed by rotary evaporation under negative pressure to obtain a self-lubricating hydroxyl acrylic polymer matrix.

[0080] Step (4) Add 0.4 parts of hydrophobic multi-walled carbon nanotubes, 0 parts of hydrophobic nano-zirconia, and 1 part of self-lubricating hydroxyl acrylic polymer matrix to 10 parts of solvent. After stirring and mixing for 30 minutes, spray it onto the substrate and cure it at room temperature for 72 hours to obtain Comparative Example 2.

[0081] The coating prepared in this comparative example, lacking the addition of nano-zirconia, exhibited significantly reduced wear resistance, losing its superhydrophobic properties after only 60 revolutions under the same conditions. Other specifications are detailed in Table 1 below.

[0082] Table 1 Comparison of Indicators between Each Example and Comparative Example

[0083] While the specific embodiments of the present invention have been described above, they are not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. A composite photothermal self-lubricating superhydrophobic anti-icing coating, characterized in that, The following components are included in parts by weight: 0.3-0.6 parts of surface-treated multi-walled carbon nanotubes; 0.2-0.4 parts of surface-treated nano-zirconia; 0.06~0.09 parts of fluorinated silane coupling agent; 0.8 to 1.4 parts of acrylate monomer mixture; Initiator 0.01~0.02 parts; 0.3 to 0.45 parts of isocyanate curing agent.

2. The composite photothermal self-lubricating superhydrophobic anti-icing coating as described in claim 1, characterized in that, The surface-treated multi-walled carbon nanotubes and nano-zirconia have undergone hydrophobic treatment by hydroxylation and silanization.

3. The composite photothermal self-lubricating superhydrophobic anti-icing coating as described in claim 1, characterized in that, The fluorinated silane coupling agent is perfluorooctyltrichlorosilane; the initiator is azobisisobutyronitrile.

4. The composite photothermal self-lubricating superhydrophobic anti-icing coating as described in claim 1, characterized in that, The acrylate monomer mixture comprises a first acrylate monomer, a second acrylate monomer, a third acrylate monomer, and a fourth acrylate monomer. The first acrylate monomer is selected from one or more of methyl methacrylate, butyl acrylate, ethylhexyl acrylate, and tert-butyl acrylate. The second acrylate monomer is selected from one or more of hydroxyethyl acrylate and hydroxypropyl acrylate. The third acrylate monomer is a monoacrylate-terminated polydimethylsiloxane. The fourth acrylate monomer is selected from one or more of 3-trimethoxysilanepropyl acrylate and methacryloxypropyltriethoxysilane.

5. The composite photothermal self-lubricating superhydrophobic anti-icing coating as described in claim 1, characterized in that, The isocyanate curing agent is one or more of hexamethylene diisocyanate, isophorone diisocyanate, and polyhexamethylene diisocyanate trimer.

6. A method for preparing a composite photothermal self-lubricating superhydrophobic anti-icing coating as described in any one of claims 1 to 5, characterized in that, include: Hydroxylation treatment of multi-walled carbon nanotubes and nano-zirconia; Hydrophobic multi-walled carbon nanotubes and nano-zirconia were subjected to silanization hydrophobic treatment using a fluorinated silane coupling agent to obtain hydrophobic multi-walled carbon nanotubes and hydrophobic nano-zirconia. A mixture of acrylate monomers was polymerized in the presence of an initiator to obtain a polymer matrix; The hydrophobic multi-walled carbon nanotubes, hydrophobic nano-zirconia, polymer matrix and isocyanate curing agent are mixed and coated on the surface of the substrate. After curing, the coating is obtained.

7. The preparation method according to claim 6, characterized in that, The hydroxylation treatment involves adding multi-walled carbon nanotubes and nano-zirconia to a mixed acid solution of sulfuric acid and nitric acid, and refluxing at 70-90°C for 3-6 hours.

8. The preparation method according to claim 6, characterized in that, The silanization hydrophobic treatment involves adding a fluorinated silane coupling agent and an alkaline catalyst to an alcohol-water mixed solvent, and reacting it with hydroxylated multi-walled carbon nanotubes and nano-zirconia at room temperature for 24-36 hours.

9. The preparation method according to claim 6, characterized in that, The polymerization reaction is carried out at 75~85℃ for 2~4 hours; the curing is carried out at room temperature for 48~72 hours.

10. The application of a composite photothermal self-lubricating superhydrophobic anti-icing coating as described in any one of claims 1 to 5 in anti-icing protection of wind turbine blade surfaces.

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