Super-hydrophobic coating with anti-icing / electrothermal deicing capability and preparation method and application thereof

Abstract

The invention discloses a super-hydrophobic coating with anti-icing / electrothermal deicing capacity and a preparation method and application thereof. The coating comprises the following components in parts by weight: 1-2 parts of Fe3O4 powder; 15 to 25 parts of a silane coupling agent; 5 to 10 parts of PTFE (Polytetrafluoroethylene) micro powder; fe3O4 is doped into a low-surface-energy substrate material PTFE, and a nano structure with honeycomb characteristics is constructed on the surface of the coating by adopting a high-pressure air gun spraying method and heat treatment. According to the method, ice on the surface of the cable is effectively removed through an anti-icing and deicing integrated strategy, and the problems of short circuit, breakage and the like of the cable caused by accumulation of the ice are effectively avoided; and the icing problem of the long-distance power transmission line is solved.

Description

Technical Field

[0001] The present invention relates to a preparation method of a cable coating with anti-icing / de-icing ability, and particularly relates to a PTFE / Fe with anti-icing / electrothermal de-icing ability 3 O 4 superhydrophobic coating and its preparation method and application Background Art

[0002] The icing phenomenon on the surface of transmission lines in the power system is likely to cause severe electrical accidents such as violent conductor galloping and ice flashover of insulator strings. In severe cases, it will also cause the line and transmission tower to be overloaded, resulting in accidents such as line breakage and tower collapse, affecting the safe operation of the power grid. The operation of the power system is closely related to all sectors of the national economy. Therefore, once an ice disaster causes a major safety accident, it will cause inestimable harm to the safe and stable operation of the power grid, all sectors of the national economy, and the normal life of residents. Therefore, the icing problem on the surface of transmission lines cannot be underestimated

[0003] At present, the main method for dealing with the icing problem of transmission lines in China is to remove the ice on the surface of transmission lines by manual or mechanical means after an ice disaster occurs to ensure the normal operation of the transmission lines. The traditional de-icing technologies at home and abroad are mainly divided into mechanical de-icing method, thermal de-icing method and chemical de-icing method. However, the current common de-icing methods cannot endow the cable with long-term anti-icing ability, and each de-icing process consumes a huge amount of manpower and material resources, and at the same time will have a negative impact on the operation of the line. In recent years, people have shifted from traditional de-icing to anti-icing research, opening up new ideas for solving the problem of surface icing. Constructing a superhydrophobic coating on the surface of the cable can make it difficult for water droplets to adhere to the surface of the cable, significantly reducing the binding force between the ice formed by water droplets under cold conditions and the surface of the cable, so that the ice on the surface of the cable can naturally fall off under natural conditions such as wind force, the self-gravity of the ice layer, temperature changes and radiation in the external environment. Such methods are simple to operate, low in cost, can be applied to the anti-icing of large-area transmission lines, and can endow the cable with long-term anti-icing ability, so they have received extensive attention in recent years. Common anti-icing coatings usually use one or several sprayable hydrophobic organic polymers as the base, supplemented by hydrophobic nanoparticles (SiO 2 、TiO 2etc.) can further enhance the hydrophobic performance of the coating. For example, Ansari A et al. (Ansari A, Saadatbakhsh M, Sohrabi M, et, al. Antifouling activity of superhydrophobic PDMS / hydrophobic silica coating. Surface Engineering, 2023, 39(1):35-48.) prepared superhydrophobic coatings by adding different contents of silica nanoparticles. In addition, constructing micro / nanostructure morphologies similar to those of butterfly wings and lotus leaf surfaces on the coating surface can further improve the hydrophobicity of the coating and reach the "superhydrophobic" critical point (> 150°). Bai H et al. (Bai H, Zhang L, Gu D, et, al. Micrometer-sized spherulites as building blocks for lotus leaf-like superhydrophobic coatings. Applied Surface Science, 2018, 459:54-62.) constructed superhydrophobic coatings with lotus leaf-like structures by using micrometer-sized spherulites. However, the superhydrophobic coatings prepared by the above methods have poor conductivity, and the cables coated with such coatings are prone to breakage when struck by lightning. Li D et al. (Li D, Sun W, Song K, et, al. Research on Differentiated Lightning Protection of Overhead Distribution Lines under Continuous Lightning Strikes. Energies, 2024, 17(18):4568.) systematically introduced the hazards of hydrophobic coatings being struck by lightning and provided some solutions. However, engineering practices in recent years have shown that even spraying materials with both lightning protection and superhydrophobic functions on the cable surface still cannot completely eliminate the problem of ice accretion on the cable surface, and the cables covered with hydrophobic coatings still have a high probability of ice accretion in extreme climates. Therefore, researchers have begun to try to load deicing materials into hydrophobic coating materials and solve the ice accretion problem of cables under extreme weather conditions through an integrated strategy of "deicing" + "anti-icing". In this context, electrothermal deicing technology is expected to become the main solution for engineering deicing under extreme climate conditions due to its characteristics such as rapid response and high efficiency. Summary of the Invention

[0004] Aiming at the problem of cable icing in the current power grid operation, the present invention provides a preparation method of a superhydrophobic coating with anti-icing / electrothermal de-icing ability. This method effectively removes the ice on the cable surface through an integrated strategy of "anti-icing + de-icing", effectively avoiding problems such as short circuits and fractures caused by ice accumulation on the cable, and solving the icing problem of long-distance transmission lines.

[0005] In the present invention, PTFE with low surface energy and excellent chemical inertness is used as the matrix, making the coating have good hydrophobicity and stability. Fe with good electrical conductivity is added 3 O 4 to provide electrothermal conversion function, and Fe 3 O 4 is silanized to transform it into a hydrophobic material to further improve the hydrophobicity of the coating. Subsequently, a honeycomb-like nanostructure is constructed on the coating surface by high-pressure air gun spraying method and heat treatment. The air in the nanostructure can transform the liquid droplets on the coating surface from the Wenzel state to the Cassie state, making the hydrophobicity of the cable coating surface reach the superhydrophobic critical point, and the liquid droplets can roll off naturally on the cable surface, making it difficult to form ice on the cable surface. The superhydrophobic effect on the cable coating surface can effectively prevent the liquid droplets from aggregating on the coating surface, making it difficult to form ice on the coating surface. For the small amount of ice crystals formed by the liquid that does not slide off by itself on the coating surface, the electrothermal de-icing effect of the cable coating can completely remove them, finally enabling the cable to operate normally in a low-temperature and humid environment, effectively reducing problems such as cable fracture and short circuit caused by cable icing.

[0006] The present invention provides a superhydrophobic coating with anti-icing / electrothermal de-icing ability, which includes the following components in parts by weight: Fe 3 O 4 powder: 1 - 2 parts; Silane coupling agent: 15 - 25 parts; PTFE micropowder: 5 - 10 parts.

[0007] The present invention provides a preparation method of a superhydrophobic coating with anti-icing / electrothermal de-icing ability, which includes the following steps: (1) Mix Fe 3 O 4 powder with a silane coupling agent and perform ultrasonic treatment to obtain modified Fe 3 O 4 powder; (2) Add PTFE micropowder to ethanol and perform ultrasonic oscillation to form a stable suspension; (3) Mix the modified Fe 3 O 4 powder with the PTFE dispersion liquid and ultrasonically disperse the mixture; (4) Use a high-pressure airless spray gun to evenly spray the mixed slurry onto the surface of the pretreated substrate; (5) Dry the sprayed substrate, and then perform heat treatment on the dried substrate.

[0008] Further feature descriptions of the above method steps are as follows: In step (1), the mass ratio of Fe 3 O 4 powder to the silane coupling agent is 1~2∶15~25, the silane coupling agent model is KH-570, and the ultrasonic treatment time is 20~40 minutes.

[0009] In step (2), the particle size of the PTFE micro-powder is 5~10 μm, the usage amount of the PTFE micro-powder is 0.3~0.7 g of PTFE added per 10 mL of ethanol, the ultrasonic oscillation time is 1~3 hours, and the ultrasonic oscillation power is 100~300 W.

[0010] In the mixed solution of step (3), the mass ratio of Fe 3 O 4 powder to the PTFE micro-powder is 1~2∶5~10, and the ultrasonic dispersion time is 1~3 hours.

[0011] In step (4), the pressure of the high-pressure airless spray gun is 50 - 100 bar. The substrate is an aluminum sheet or an aluminum cable In step (5), the drying temperature of the substrate is controlled at 60~80 °C, the drying time is 10~20 minutes, the heat treatment temperature is controlled at 250~400 °C, the heat treatment time is 2~4 hours, and the heating rate used in the heat treatment process is 2 °C / min to avoid substrate deformation.

[0012] The beneficial effects of the present invention are as follows: (1) In this method, modified iron oxide (Fe 3 O 4 ) is innovatively doped into the low surface energy base material PTFE, and a nano-structure with honeycomb characteristics is constructed on the coating surface by using the high-pressure air gun spraying method and heat treatment. Experimental results show that after the high-pressure air gun spraying method and heat treatment, a uniformly distributed nano-scale pore structure is formed on the coating surface, and its high specific surface area and porosity can effectively capture and store a large amount of air, significantly improving the hydrophobic performance of the coating. After testing, the contact angle on the surface of the cable coating reaches the superhydrophobic critical value (>150°), and the liquid droplets can achieve a self-cleaning effect on the cable surface, greatly reducing the possibility of surface icing formation.

[0013] (2) Based on Fe 3 O 4Excellent electrical and thermal conductivity characteristics (its intrinsic electrical conductivity can reach 5×10³ S / m (300 K), and it also has a longitudinal thermal conductivity as high as 90 W / (m·K)). Introducing Fe into the matrix material 3 O 4 can significantly reduce the surface resistance of the coating (about 1.2×10² Ω / sq), enabling the cable coating to simultaneously possess excellent electrothermal de-icing performance and lightning protection performance. Experiments have confirmed that under the condition of applying a low voltage (<36 V), the coating can effectively remove the surface ice layer within 60 seconds, ensuring the normal operation of the cable under extreme weather conditions.

[0014] (3) Research has shown that a coating with good insulation will cause the cable to break when struck by lightning. However, in the coating material of the present invention, the addition of Fe 3 O 4 can significantly improve the lightning protection effect of the cable, enabling the cable to operate under extreme weather conditions.

[0015] (4) PTFE has excellent chemical inertness (resistant to acids and alkalis in the pH range of 0 - 14) and high thermal stability (decomposition temperature >400°C). This coating can withstand drastic temperature changes (-40°C to 80°C) without structural damage. Accelerated aging experiments have shown that after multiple thermal cycles, the coating remains intact without cracking or peeling, demonstrating excellent cyclic stability and meeting the requirements for long-term outdoor use.

[0016] (5) The implementation of the present invention will provide important technical guarantees for the safe operation of the power system under extreme climate conditions, and has significant social and economic benefits and application value for promotion. Brief Description of the Drawings

[0017] Figure 1 is the SEM image of the PTFE / Fe 3 O 4 coating and the heat-treated PTFE / Fe 3 O 4 coating under the conditions of Example 3; Figure 2 is the heat-treated PTFE / Fe 3 O 4 coating under the conditions of Example 3: (a) experimental results of hydrophobic performance and (b) cross-linking impedance test results; Figure 3 is the heat-treated PTFE / Fe 3 O 4 coating under the conditions of Example 3 under sunlight irradiation: (a) experimental results of electrothermal temperature rise, (b) electrothermal temperature rise curve, (c) temperature rise - fall cycle curve, and (d) electrothermal efficiency curve; Figure 4It is the experimental result of the anti-icing ability and electrothermal de-icing ability of the PTFE / Fe coating after heat treatment under the conditions of Example 3 3 O 4 coating; Figure 5 It is the experimental result of the de-icing ability of the aluminum cable and the PTFE / Fe 3 O 4 coated cable in the outdoor real environment (about 2 °C): (a) The experimental result of the de-icing ability of the aluminum sheet in the outdoor real environment; (b) The experimental result of the de-icing ability of the PTFE / Fe 3 O 4 coated cable in the outdoor real environment. Detailed implementation mode

[0018] To better understand the present invention, the following further detailed description of the present invention is made in conjunction with the drawings and embodiments, but the scope claimed by the present invention is not limited to the scope represented by the embodiments.

[0019] The particle size of the PTFE micro-powder selected in the following embodiments is 5-10 μm. Example 1

[0020] A preparation method of a superhydrophobic coating with anti-icing / electrothermal de-icing ability is provided, and the preparation method is carried out according to the following steps: Step 1: Mix 0.01 g of Fe 3 O 4 powder with 0.2 g of silane coupling agent and ultrasonically treat for 30 minutes; Step 2: Add 0.1 g of PTFE micro-powder to 2 mL of ethanol, ultrasonically oscillate for 2 hours (power 200 W) to form a stable suspension; Step 3: Mix the modified Fe 3 O 4 powder with the PTFE dispersion and ultrasonically disperse for 1 hour; Step 4: Use a high-pressure airless spraying gun (pressure 50 bar) to evenly spray the mixed slurry onto the surfaces of the pretreated aluminum sheet and aluminum cable substrate; Step 5: Dry at 80 °C for 10 minutes, and then heat-treat at 400 °C for 2 hours to construct a nanostructure on the coating surface to make the hydrophobicity of the cable coating surface reach the "superhydrophobic" critical point. Example 2

[0021] A preparation method of a superhydrophobic coating with anti-icing / electrothermal de-icing ability is provided, and the preparation method is carried out according to the following steps: Step 1: Mix 0.03 g of Fe 3 O 4The powder was mixed with 0.6 g of silane coupling agent and ultrasonicated for 30 minutes; Step 2: 0.2 g of PTFE micropowder was added to 4 mL of ethanol and ultrasonically oscillated for 2 hours (power 200 W) to form a stable suspension; Step 3: The modified Fe 3 O 4 powder was mixed with the PTFE dispersion and ultrasonically dispersed for 1.5 hours; Step 4: The mixed slurry was evenly sprayed onto the surface of the pretreated substrate using a high-pressure airless spraying gun (pressure 50 bar); Step 5: It was dried at 70 °C for 10 minutes and then heat-treated at 350 °C for 2 hours to construct a nanostructure on the coating surface, so that the hydrophobicity of the cable coating surface reached the "superhydrophobic" critical point. Example 3

[0022] A preparation method of a superhydrophobic coating with anti-icing / electric heating de-icing ability is provided, and this preparation method is carried out according to the following steps: Step 1: 0.05 g of Fe 3 O 4 powder was mixed with 1 g of silane coupling agent and ultrasonicated for 30 minutes; Step 2: 0.5 g of PTFE micropowder was added to 10 ml of ethanol and ultrasonically oscillated for 2 hours (power 200 W) to form a stable suspension; Step 3: The modified Fe 3 O 4 powder was mixed with the PTFE dispersion and ultrasonically dispersed for 2 hours; Step 4: The mixed slurry was evenly sprayed onto the surface of the pretreated substrate using a high-pressure airless spraying gun (pressure 50 bar); Step 5: It was dried at 80 °C for 20 minutes and then heat-treated at 300 °C for 2 hours to construct a nanostructure on the coating surface, so that the hydrophobicity of the cable coating surface reached the "superhydrophobic" critical point.

[0023] For the PTFE / Fe 3 O 4 coating (after drying, without heat treatment) and the PTFE / Fe 3 O 4 coating after heat treatment, the performance was detected, as shown in Figures 1 - 5 shown.

[0024] The microscopic morphology is as Figure 1 shown. It can be seen from the figure that for the PTFE / Fe 3 O 4The particle size on the coating surface is 100 - 200 nm. After heat treatment, a honeycomb nanostructure composed of larger nanocolumns is formed on the coating surface. The high porosity of the honeycomb nanostructure enables the coating to store a large amount of air, thereby effectively improving the hydrophobic performance of the coating. Figure 2 (a) and (b) show the contact angle experimental results of the PTFE / Fe 3 O 4 coating after heat treatment. The experimental results show that the contact angle of the untreated glass workpiece is 31.2°, showing hydrophilicity. After surface modification with PTFE and PTFE / Fe 3 O 4 coatings, the workpiece surface begins to show hydrophobicity, but its contact angle is far lower than the superhydrophobic standard. After heat treatment of the PTFE / Fe 3 O 4 coating, the contact angle on the coating surface rises to 157.19°, and the coating surface shows good superhydrophobic performance, providing a basis for anti-icing / rapid de-icing on the coating surface. Figure 2 (c) is the AC impedance experimental result of the PTFE / Fe 3 O 4 coating after heat treatment. The results show that the PTFE / Fe 3 O 4 coating after heat treatment can effectively reduce the surface impedance of the material, endowing the material surface with certain electrical conductivity, providing the possibility for electrothermal de-icing of the coating. Figure 3 (a) and (b) are the electrothermal heating experimental results of the PTFE / Fe 3 O 4 coating under the condition of an applied voltage of 4 V. The results show that the surface temperatures of the PTFE / Fe 3 O 4 coating and the PTFE / Fe 3 O 4 coating after heat treatment rise to 47.7 °C and 54.4 °C respectively within 70 s, while the temperatures of the bare workpiece group and the PTFE coating group can only rise to 31.5 - 33.3 °C under the same applied voltage, indicating that the PTFE / Fe 3 O 4 coating can endow the workpiece with good electrothermal conversion performance. Figure 3 (c) is the heating-cooling curve of the PTFE / Fe 3 O 4 coating after heat treatment. The experimental results show that the electrothermal conversion performance of the PTFE / Fe 3 O 4 coating after heat treatment has good stability. Figure 3 d is the PTFE / Fe 3 O 4Coating electrothermal conversion efficiency curve, and the results show that the coating electrothermal conversion efficiency can reach over 90%. Figure 4 is PTFE / Fe after heat treatment 3 O 4 De-icing process of the coating under the condition of applying 4 V voltage in a cold environment. The experimental results show that the ice on the surface of the bare workpiece can be observed to melt after 240 s of power-on, while for the PTFE / Fe 3 O 4 coating, the ice on the surface completely melts only after 60 s of power-on, indicating that the PTFE / Fe 3 O 4 coating has good anti-icing / electrothermal de-icing ability. Figure 5 is the de-icing process of an aluminum cable and a PTFE / Fe 3 O 4 coated cable under the condition of applying 4 V voltage in a real cold outdoor environment (about 2 °C). The results show that the surface ice layer of the aluminum stranded wire can be observed to start melting after 240 s of power-on, while for the PTFE / Fe 3 O 4 coated cable, it starts to melt only after 40 s of power-on and completely melts until 60 s, indicating that the coated cable has excellent electrothermal conversion de-icing ability.

Claims

1. A super hydrophobic coating with anti-icing / electrothermal deicing capability, characterized in that The composition comprises the following components in parts by weight: Fe3O4 powder: 1~2 parts; Silane coupling agent: 15~25 parts; PTFE micro powder: 5~10 parts.

2. The super-hydrophobic coating with anti-icing / electro-thermal deicing capability according to claim 1, characterized in that The following steps are involved: (1) Fe3O4 powder is mixed with a silane coupling agent and subjected to ultrasonic treatment to obtain a modified Fe3O4 powder; (2) PTFE powder is added to ethanol and subjected to ultrasonic oscillation to form a stable suspension; (3) mixing the modified Fe3O4 powder with PTFE dispersion and dispersing the mixture by ultrasonication; (4) Use a high-pressure airless spray gun to evenly spray the mixed slurry onto the pretreated substrate surface; (5) Drying the sprayed substrate, and then heat treating the dried substrate.

3. The super-hydrophobic coating with anti-icing / electro-thermal deicing capability according to claim 2, characterized in that: In step (1), the mass ratio of Fe3O4 powder to silane coupling agent is 1-2:15-25, the model of silane coupling agent is KH-570, and the ultrasonic treatment time is 20-40 minutes.

4. The super-hydrophobic coating with anti-icing / electro-thermal deicing capability according to claim 2, characterized in that: In step (2), the particle size of the PTFE powder is 5-10 μm, the amount of PTFE powder used is 0.3-0.7 g PTFE per 10 mL ethanol, the ultrasonic oscillation time is 1-3 hours, and the ultrasonic oscillation power is 100-300 W.

5. The super-hydrophobic coating with anti-icing / electro-thermal deicing capability according to claim 2, characterized in that: The mass ratio of Fe3O4 powder to PTFE powder in the mixed solution of step (3) is 1-2:5-10, and the ultrasonic dispersion time is 1-3 hours.

6. The super-hydrophobic coating with anti-icing / electro-thermal deicing capability according to claim 2, characterized in that: In step (4), the pressure of the high-pressure airless spray gun is 50-100 bar; and the substrate is an aluminum sheet or an aluminum cable.

7. The super-hydrophobic coating with anti-icing / electro-thermal deicing capability according to claim 2, characterized in that: In step (5), the substrate drying temperature is controlled at 60-80°C, the drying time is 10-20 minutes, the heat treatment temperature is controlled at 250-400°C, the heat treatment time is 2-4 hours, and the heating rate used in the heat treatment process is 2°C / min to avoid deformation of the substrate.

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