An anti-icing coating for the surface of a transmission line and its preparation method

Abstract

The present invention discloses an anti-icing coating for the surface of a transmission line and a preparation method thereof, specifically: First, prepare a carbon vesicle precursor. Second, perform carbonization treatment and template removal. Then, prepare a surface layer coating and a bottom layer coating. Finally, prepare an anti-icing composite coating to obtain an anti-icing coating with high durability and strong stability. The anti-icing coating prepared by the present invention uses the super-slip surface formed by a lubricant to effectively delay the icing of droplets and promote the shedding of water and ice. When the lubricant is consumed, the surface restores superhydrophobicity and can also prevent water and ice from freezing. At the same time, the coating has excellent photothermal effects, ensuring its efficient heat generation and ice removal under sunlight to achieve a long-term anti-icing effect. In addition, the coating is covalently bonded to the transmission line and has good mechanical stability. The anti-icing coating prepared by the present invention solves the problems of poor anti-icing durability and poor mechanical stability of the coating in a low-temperature and high-humidity environment, and has important application prospects in the field of transmission line anti-icing.

Description

Technical Field

[0001] The present invention belongs to the field of anti-icing, and particularly relates to an anti-icing coating for the surface of a transmission line and a preparation method thereof. Background Art

[0002] Surface icing can affect the stability of transmission lines and easily lead to significant economic losses and safety hazards. Traditional de-icing technologies, such as mechanical de-icing, chemical de-icing, and thermal de-icing, usually have the disadvantages of low efficiency, high energy consumption, and the need for specific de-icing facilities, which limits their practical applications. By adopting the strategy of coating anti-icing coatings, inhibiting or delaying the formation of ice on the material surface, reducing the bonding strength of the surface ice layer and the amount of ice accretion, and solving the icing problem from the source has become the main research direction. Anti-icing coatings mainly include hydrated self-lubricating coatings, super-slip coatings infused with lubricants, superhydrophobic coatings, and photothermal coatings, etc. Although these anti-icing coatings have the advantages of high-efficiency anti-icing and low energy consumption, there are still problems such as poor anti-icing durability and poor mechanical stability at present, which makes it difficult to ensure the effective protection and long-term service of the coatings in extremely low-temperature environments.

[0003] Zhang et al. (Lishen Zhang, Alvin G. Zhou, Brigitta R. Sun, et al. Functional and versatile superhydrophobic coatings via stoichiometric silanization [J]. Nature Communications, 2021, 12: 982.) prepared a superhydrophobic coating with a micro-nano porous structure based on unconventional, stoichiometrically controlled organosilane polymerization, which has excellent superhydrophobicity and mechanical stability. However, in a long-term low-temperature and high-humidity environment, supercooled water droplets will condense in the micro-nano structures of the superhydrophobic surface, form a mechanical interlock with the interface, increase the adhesion strength of the ice layer, and cause the coating to lose its anti-icing effect.

[0004] Cao Jingyi et al. (Cao Jingyi, Zhang Haiyong, Yang Wenjing, et al. Preparation and properties of KCC-1 / PVDF superhydrophobic and super-slippery surfaces [J]. Surface Technology, 2020, 49(6): 152-158.) compounded sea urchin-like nano-silica particles with polyvinylidene fluoride, and infused dimethyl silicone oil after hydrophobic modification to obtain a super-slip surface. The super-slip surface can effectively delay the icing of droplets on the surface and has good wear resistance. However, in a long-term complex environment, as the lubricant is consumed, the coating gradually loses its super-slip performance and shows poor anti-icing durability.

[0005] Chinese Patent "A Preparation Method of a Bionic Self-Cleaning Superhydrophobic Anti-Icing Coating" (Application No.: 202210147381.0, Publication No. of Application: CN 114622203 A, Publication Date: June 14, 2022) discloses a bionic superhydrophobic anti-icing coating. The superhydrophobic surface is obtained by constructing a micro-nano scale stepped structure and modifying with low surface energy materials, which can delay the freezing of droplets in a low-temperature environment. However, when the droplets on the coating surface freeze into ice, not only does the anti-icing performance of the coating disappear, but also the ice accumulated on the surface is difficult to remove; in addition, the mechanical stability of the coating is also poor.

[0006] Chinese Patent "An Anti-Icing Coating Suitable for Power Grid Equipment, Its Preparation Method and Application" (Application No.: 202010446433.5, Authorization Publication No.: CN 111548730 B, Publication Date: November 30, 2021) discloses a photothermal anti-icing coating, which endows the coating with an energy-gathering effect under sunlight through zirconia, ruthenium oxide and cobalt ferrite nano-fillers, achieving the effects of preventing ice formation and photothermal de-icing. However, the absorption and utilization rate of sunlight by the coating is relatively low, and the continuous anti-icing effect is not good in weak light and dark environments.

[0007] Chinese Patent "A Photothermal Hydrophobic Anti-Icing and Anti-Shedding Coating Material, Its Preparation and Application" (Application No.: 202111554417.9, Publication No. of Application: CN 114231113 A, Publication Date: March 25, 2022) discloses a photothermal hydrophobic anti-icing and anti-shedding coating, which contains modified acrylic resin, hydrophobic particles and photothermal conversion particles, and has good adhesion and anti-shedding properties, superhydrophobicity and photothermal characteristics. It can not only delay the formation of ice, but also de-ice by photothermal effect. However, the ability of the coating to make droplets fall off automatically still needs to be improved. In addition, most of the photothermal conversion particles are located inside the coating, and the photothermal effect is not obvious, and the anti-icing durability is difficult to guarantee. Summary of the Invention

[0008] The object of the present invention is to provide an anti-icing coating for the surface of transmission lines and its preparation method, which solves the problems of poor anti-icing durability and poor mechanical stability of the coating in extremely low temperature environments.

[0009] The technical solution adopted by the present invention is as follows:

[0010] A preparation method of an anti-icing coating for the surface of transmission lines is specifically implemented according to the following steps:

[0011] Step 1, prepare a carbon vesicle precursor:

[0012] Tetraethyl orthosilicate, ammonia water, ethanol, and deionized water were mixed and stirred for the first time. Then, resorcinol and formaldehyde were added thereto and stirred for the second time. Tetraethyl orthosilicate was added again and stirred for the third time. Then, hydrothermal treatment was carried out. Finally, carbon vesicle precursors, namely silica@resorcinol formaldehyde resin-silica, were obtained through centrifugation and drying.

[0013] Step 2, carbonization treatment and template removal:

[0014] The carbon vesicle precursors obtained in Step 1 were carbonized under a nitrogen atmosphere. After cooling to room temperature, they were dispersed into an alkaline solution and stirred for etching to remove the silica template. Subsequently, centrifugation, washing with water, and drying were carried out to obtain hollow nano-carbon vesicles.

[0015] Step 3, preparation of the topcoat and the primer:

[0016] The hollow nano-carbon vesicles obtained in Step 2 were mixed with a polydimethylsiloxane prepolymer, a solvent, a lubricant, and a curing agent. After stirring evenly, degassing was carried out under vacuum to obtain the topcoat.

[0017] Octadecyltrichlorosilane and deionized water were mixed. After ultrasonic dispersion, hydrolysis was carried out at a constant temperature and left standing. Then, n-hexane was added and stirred evenly to obtain the primer containing siloxane aggregates.

[0018] Step 4, preparation of the anti-icing composite coating:

[0019] The pre-treated transmission line was soaked with the primer obtained in Step 3. After drying and curing, a primer layer was formed on the surface of the transmission line substrate. The topcoat was sprayed on the surface of the transmission line with the primer layer. After heat curing treatment, a highly durable anti-icing composite coating was obtained.

[0020] Preferably, the mass percentages of the initially added tetraethyl orthosilicate, ammonia water, ethanol, deionized water, resorcinol, formaldehyde, and the secondarily added tetraethyl orthosilicate in Step 1 are 1.8% - 6.8%, 1.7% - 3.3%, 71.7% - 74.8%, 12.7% - 19%, 0.2% - 0.3%, 0.4% - 0.8%, and 2.1% - 4.4% respectively, and the sum of the above components is 100%; the stirring speed is 200 - 500 rpm, the first stirring time is 20 - 24 h, the second stirring time is 5 - 7 h, the third stirring time is 20 - 30 h; the hydrothermal temperature is 90 - 100 °C, the hydrothermal time is 12 - 15 h; the centrifugation speed is 6000 - 8000 rpm, the centrifugation time is 3 - 5 min; the drying temperature is 50 - 60 °C, the drying time is 8 - 12 h.

[0021] Preferably, in the step 2, the carbonization temperature is 700 - 800 °C, the carbonization time is 1 - 2 h, the alkaline solution is any one of sodium hydroxide solution and sodium carbonate solution, the concentration of the alkaline solution is 0.6 - 2 mol / L, the stirring speed is 400 - 600 rpm, the etching time is 6 - 12 h, the centrifugation speed is 8000 - 10000 rpm, the centrifugation time is 3 - 5 min, the number of water washing times is 3 - 4 times, the drying temperature is 50 - 80 °C, and the drying time is 8 - 12 h.

[0022] Preferably, in the step 3, the topcoat is composed of the following substances by mass percentage: 0.5 - 0.7% of hollow nano carbon vesicles, 18.3 - 22% of polydimethylsiloxane prepolymer, 44.7 - 55% of solvent, 20.1 - 34.7% of lubricant, and 1.8 - 2.2% of curing agent. The sum of the above components is 100%. The polydimethylsiloxane prepolymer is SYLGARD 184A, the curing agent is SYLGARD 184B, the solvent is any one of xylene, ethyl acetate, n - hexane, and tetrahydrofuran, the lubricant is one of silicone oil, ethyl oleate, and perfluoropolyether oil, the stirring speed is 300 - 500 rpm, the stirring time is 0.5 - 1 h, and the degassing time is 10 - 30 min.

[0023] Preferably, in the step 3, the primer is composed of the following substances by mass percentage: 5.6 - 9% of octadecyltrichlorosilane, 0.1 - 0.2% of deionized water, and 90.8 - 94.3% of n - hexane. The sum of the above components is 100%. The ultrasonic power is 100 W, the ultrasonic time is 3 - 5 min, the hydrolysis temperature is 25 - 30 °C, the hydrolysis time is 2 - 4 h, the stirring speed is 300 - 500 rpm, and the stirring time is 0.5 - 1 h.

[0024] Preferably, in the step 4, the pretreatment of the transmission line includes sandpaper grinding, polishing, and degreasing. The soaking time is 30 - 60 min, the drying temperature is 50 - 60 °C, the drying time is 0.5 - 1 h. The spraying equipment provides air pressure through an air compressor, the air pressure is 0.2 - 0.4 MPa, the spraying distance is 15 - 20 cm, and the spraying amount is 0.4 - 0.5 mL / cm 2 , the thermal curing temperature is 60 - 70 °C, and the thermal curing time is 2 - 3 h.

[0025] An anti-icing coating for the surface of a transmission line prepared by the method for preparing an anti-icing coating for the surface of a transmission line according to the above, includes a bottom coating composed of micro-nano porous silicon oxide aggregates and a surface coating composed of a lubricant and hollow nano-carbon vesicles, which are successively attached to the surface of the transmission line substrate from the inside to the outside. Among them, the hollow nano-carbon vesicles have an inner layer, an outer layer and a sandwich layer between the two. The inner diameter of the hollow nano-carbon vesicles is 80 - 120 nm, the outer diameter is 120 - 160 nm, the thickness of both the inner layer and the outer layer is 2 - 3 nm, the thickness of the sandwich layer between the inner layer and the outer layer is 10 - 14 nm, and the thickness of the anti-icing composite coating is 20 - 40 μm.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] A method for preparing an anti-icing coating for the surface of a transmission line, which coats a highly durable and strongly stable anti-icing composite coating on the surface of the transmission line. The micro-nano porous hierarchical structure jointly composed of silicon oxide aggregates and hollow nano-carbon vesicles in the coating can provide a large amount of storage space for the lubricant. The exudation of the lubricant will form a super-slip layer on the surface of the coating, prolong the freezing time of the droplets, and promote the shedding of the droplets. Even when the lubricant is exhausted, the exposed super-hydrophobic surface formed by the silicon oxide aggregates with low surface energy also has excellent hydrophobic and ice-phobic properties, and can also achieve the anti-icing function; when icing occurs, the coating can utilize the light trapping effect of the micro-nano porous hierarchical structure and the broad-spectrum light absorption and photothermal effect of the hollow nano-carbon vesicles to achieve efficient photothermal de-icing under sunlight irradiation. At the same time, it can also improve the photothermal de-icing through the oil layer formed by the lubricant, and weaken the adhesion strength between the ice layer and the coating, making the ice easy to remove, achieving the effect of ice-phobicity; in addition, the coating utilizes the rich reactive sites (-Si-OH) in the bottom coating to achieve covalent bonding with the transmission line substrate, significantly improving the mechanical stability of the composite coating. The anti-icing composite coating prepared by the present invention solves the problems of poor anti-icing durability and poor mechanical stability of the existing transmission line coatings, and has an important application prospect in the field of transmission line anti-icing. Description of the Drawings

[0028] Figure 1 is a schematic diagram of an anti-icing coating for the surface of a transmission line prepared by the method for preparing an anti-icing coating for the surface of a transmission line of the present invention.

[0029] In the figure, 1 - transmission line substrate, 2 - anti-icing coating, 3 - bottom coating, 4 - surface coating, 5 - polydimethylsiloxane, 6 - lubricant, 7 - hollow nano-carbon vesicles, 8 - outer layer, 9 - nano-porous sandwich layer, 10 - inner layer. Detailed Embodiments

[0030] The present invention will be described in detail below with reference to the drawings and specific embodiments.

[0031] A preparation method of an anti-icing coating on the surface of a transmission line is specifically implemented according to the following steps:

[0032] Step 1, prepare the carbon vesicle precursor:

[0033] Mix tetraethyl orthosilicate, ammonia water, ethanol and deionized water and conduct the first stirring at a stirring speed of 200 - 500 rpm for 20 - 24 h. Add resorcinol and formaldehyde thereto and conduct the second stirring at a stirring speed of 200 - 500 rpm for 5 - 7 h. Add tetraethyl orthosilicate again and conduct the third stirring for 20 - 30 h. Then conduct hydrothermal treatment at 90 - 100 °C for 12 - 15 h. Finally, centrifuge at a rotation speed of 6000 - 8000 rpm for 3 - 5 min and dry at 50 - 60 °C for 8 - 12 h to obtain the carbon vesicle precursor, namely silica@resorcinol formaldehyde resin - silica.

[0034] In Step 1, the mass percentages of the initially added tetraethyl orthosilicate, ammonia water, ethanol, deionized water, resorcinol, formaldehyde and the secondarily added tetraethyl orthosilicate are 1.8% - 6.8%, 1.7% - 3.3%, 71.7% - 74.8%, 12.7% - 19%, 0.2% - 0.3%, 0.4% - 0.8% and 2.1% - 4.4% respectively, and the sum of the above components is 100%.

[0035] Step 2, carbonization treatment and template removal:

[0036] Place the carbon vesicle precursor obtained in Step 1 under a nitrogen atmosphere at 700 - 800 °C for carbonization for 1 - 2 h. After cooling to room temperature, disperse it into an alkali solution with a concentration of 0.6 - 2 mol / L and stir and etch at a speed of 400 - 600 rpm for 6 - 12 h to remove the silica template. Then centrifuge at a rotation speed of 8000 - 10000 rpm for 3 - 5 min, wash 3 - 4 times with water, and dry at 50 - 80 °C for 8 - 12 h to obtain hollow nano - carbon vesicles.

[0037] In Step 2, the alkali solution is any one of sodium hydroxide solution and sodium carbonate solution. The hollow nano - carbon vesicles have an inner layer, an outer layer and a sandwich layer between the two. The inner diameter of the hollow nano - carbon vesicles is 80 - 120 nm, the outer diameter is 120 - 160 nm, the thicknesses of both the inner layer and the outer layer are 2 - 3 nm, and the thickness of the sandwich layer between the inner layer and the outer layer is 10 - 14 nm.

[0038] Step 3, prepare the surface coating and the bottom coating:

[0039] Mix the hollow nano-carbon vesicles obtained in step 2 with a polydimethylsiloxane prepolymer, a solvent, a lubricant, and a curing agent, stir at a stirring speed of 300 - 500 rpm for 0.5 - 1 h, and then degas under vacuum for 10 - 30 min to obtain a surface coating; Mix octadecyltrichlorosilane with deionized water, ultrasonically disperse at a power of 100 W for 3 - 5 min, then stand for hydrolysis at 25 - 30 °C for 2 - 4 h, and then add n-hexane, stir at a stirring speed of 300 - 500 rpm for 0.5 - 1 h to obtain a bottom coating containing siloxane aggregates.

[0040] The surface coating is composed of the following substances by mass percentage: 0.5 - 0.7% of hollow nano-carbon vesicles, 18.3 - 22% of polydimethylsiloxane prepolymer, 44.7 - 55% of solvent, 20.1 - 34.7% of lubricant, and 1.8 - 2.2% of curing agent, and the sum of the above components is 100%. The polydimethylsiloxane prepolymer is SYLGARD 184A, the curing agent is SYLGARD 184B, the solvent is any one of xylene, ethyl acetate, n-hexane, and tetrahydrofuran, and the lubricant is one of silicone oil, ethyl oleate, and perfluoropolyether oil.

[0041] The bottom coating is composed of the following substances by mass percentage: 5.6 - 9% of octadecyltrichlorosilane, 0.1 - 0.2% of deionized water, and 90.8 - 94.3% of n-hexane, and the sum of the above components is 100%.

[0042] Step 4, prepare an anti-icing composite coating:

[0043] Soak the power transmission line pretreated by sandpaper polishing and degreasing with the bottom coating obtained in step 3 for 30 - 60 min, dry and cure at 50 - 60 °C for 0.5 - 1 h, then under an air pressure of 0.2 - 0.4 MPa, maintain a spraying distance of 15 - 20 cm and a spraying amount of 0.4 - 0.5 mL / cm 2 Spray the surface coating on its surface, and after heat curing at 60 - 70 °C for 2 - 3 h, obtain an anti-icing composite coating with a thickness of 20 - 40 μm.

[0044] Figure 1 It is a schematic diagram of the anti-icing coating on the surface of the power transmission line prepared by the present invention. As can be seen from the figure, the anti-icing coating 2 includes a bottom coating 3 composed of micro-nano porous siloxane aggregates and a surface coating 4 composed of a lubricant 6 and hollow nano-carbon vesicles 7 attached to the surface of the power transmission line substrate 1 in sequence from the inside to the outside. The porous siloxane aggregates are formed by entangling nanofibers and are covalently bonded to the surface of the power transmission line; the hollow nano-carbon vesicles 7 have a thin inner layer 10, a rough outer layer 8, and a nano-porous interlayer 9, and are adhered to the siloxane aggregates through polydimethylsiloxane 5. The lubricant 6 will form an oil layer on the surface of the coating to achieve the super-slip function.

[0045] A preparation method of an anti-icing coating on the surface of a transmission line. Through the co-condensation of silica and resorcinol-formaldehyde resin, and subsequent carbonization and template etching treatments, hollow nano-carbon vesicles with a thin inner layer, a rough outer layer, and a nano-porous interlayer are prepared, achieving the purposes of enhancing broadband light absorption and photothermal performance, adsorbing and storing lubricants, and increasing the surface roughness of the coating; controlling the contents of the nano-carbon vesicles and the lubricants to obtain a surface layer photothermal super-slip coating, which can delay droplet freezing, reduce ice adhesion, and de-ice by photothermal means, realizing long-term anti-icing and ice-phobic effects; by adjusting the stoichiometric ratio of octadecyltrichlorosilane and water in the bottom coating, micro-nano porous siloxane aggregates with low surface energy are obtained, which can not only store lubricants but also exhibit excellent superhydrophobic, light-trapping, anti-wear, and mechanical stability properties; combining dip coating and spraying methods to construct a composite coating with a hierarchical structure on the surface of the transmission line, which can not only achieve better anti-icing and de-icing effects but also improve the adhesion and anti-shedding performance of the coating.

[0046] The present invention coats a highly durable and strongly stable anti-icing composite coating on the surface of a transmission line. The micro-nano porous hierarchical structure jointly composed of siloxane aggregates and hollow nano-carbon vesicles in the coating can provide a large amount of storage space for lubricants, and the exudation of the lubricants will form a super-slip layer on the surface of the coating, prolonging the freezing time of droplets and facilitating the shedding of droplets. Even when the lubricants are exhausted, the exposed superhydrophobic surface formed by siloxane aggregates with low surface energy also has excellent hydrophobic and ice-phobic properties, and can also achieve the anti-icing function; when icing occurs, the coating can utilize the light-trapping effect of the micro-nano porous hierarchical structure and the broadband light absorption and photothermal effects of the carbon vesicles to achieve efficient photothermal de-icing under sunlight irradiation. At the same time, the oil layer formed by the lubricants can be used to improve photothermal de-icing and weaken the adhesion strength between the ice layer and the coating, making the ice easy to remove, achieving the ice-phobic effect; in addition, the coating utilizes the abundant reactive sites (-Si-OH) in the bottom coating to achieve covalent bonding with the transmission line substrate, significantly improving the mechanical stability of the composite coating. The anti-icing composite coating prepared by the present invention solves the problems of poor anti-icing durability and poor mechanical stability of the existing transmission line coatings, and has important application prospects in the field of transmission line anti-icing.

[0047] Example 1

[0048] Mix 10 mL of tetraethyl orthosilicate, 10 mL of ammonia water, 500 mL of ethanol, and 100 mL of deionized water and stir for the first time at 300 rpm for 24 h. Add 0.9 g of resorcinol and 2 mL of formaldehyde thereto and stir for the second time at 300 rpm for 5 h. Add 12 mL of tetraethyl orthosilicate again and stir for the third time at 300 rpm for 24 h. Then perform hydrothermal treatment at 100 °C for 12 h. Finally, centrifuge at 8000 rpm for 5 min and dry at 60 °C for 12 h to obtain a carbon vesicle precursor, namely silica@resorcinol formaldehyde resin-silica;

[0049] The carbon vesicle precursor was carbonized in a nitrogen atmosphere at 800 °C for 2 h. After cooling to room temperature, it was dispersed in a 2 mol / L sodium hydroxide solution and etched by stirring at a speed of 400 rpm for 6 h to remove the silica template. Subsequently, it was centrifuged at 10000 rpm for 5 min, washed with water three times, and dried at 80 °C for 8 h to obtain hollow nano-carbon vesicles (the hollow nano-carbon vesicles have a thin inner layer, a rough outer layer, and a nanoporous interlayer between the two. The inner diameter is 100 nm, the outer diameter is 128 nm, the thickness of both the inner layer and the outer layer is 2 nm, and the thickness of the porous interlayer between the inner layer and the outer layer is 10 nm);

[0050] 0.1 g of the hollow nano-carbon vesicles was mixed with 3.66 g of polydimethylsiloxane prepolymer SYLGARD 184A, 8.94 g of xylene, 6.94 g of silicone oil, and 0.36 g of curing agent SYLGARD 184B. After stirring at 300 rpm for 1 h, it was degassed under vacuum for 30 min to obtain the surface layer coating; 2.8 mL of octadecyltrichlorosilane was mixed with 0.056 mL of deionized water, ultrasonically dispersed at a power of 100 W for 5 min, then left to hydrolyze at 25 °C for 4 h, and then 47 mL of n-hexane was added and stirred at 300 rpm for 1 h to obtain the bottom layer coating containing silicone aggregates;

[0051] First, the power transmission line pretreated by grinding, polishing, and degreasing was soaked in the bottom layer coating for 60 min. After drying and curing at 60 °C for 1 h, under an air pressure of 0.2 MPa, maintaining a spraying distance of 15 cm and a spraying amount of 0.4 mL / cm 2 the surface layer coating was sprayed onto its surface. After heat curing treatment at 70 °C for 2 h, a 20-μm-thick anti-icing composite coating was obtained.

[0052] Example 2

[0053] 10 mL of tetraethyl orthosilicate, 5 mL of ammonia water, 125 mL of ethanol, and 50 mL of deionized water were mixed and stirred for the first time at 500 rpm for 20 h. After adding 0.45 g of resorcinol and 1 mL of formaldehyde, it was stirred for the second time for 5 h. Then 16 mL of tetraethyl orthosilicate was added again and stirred for the third time for 30 h. Then it was hydrothermally treated at 100 °C for 14 h. Finally, it was centrifuged at 6000 rpm for 5 min and dried at 50 °C for 12 h to obtain the carbon vesicle precursor, namely silica@resorcinol formaldehyde resin-silica;

[0054] The carbon vesicle precursor was carbonized at 800 °C in a nitrogen atmosphere for 2 h. After cooling to room temperature, it was dispersed in a 0.6 mol / L sodium carbonate solution and etched by stirring at a speed of 600 rpm for 12 h to remove the silica template. Subsequently, it was centrifuged at 10000 rpm for 3 min, washed with water 4 times, and dried at 50 °C for 12 h to obtain hollow nano-carbon vesicles (the hollow nano-carbon vesicles have a thin inner layer, a rough outer layer, and a nanoporous interlayer between the two. The inner diameter is 100 nm, the outer diameter is 140 nm, the thickness of both the inner layer and the outer layer is 3 nm, and the thickness of the porous interlayer between the inner layer and the outer layer is 14 nm);

[0055] 0.14 g of the hollow nano-carbon vesicles was mixed with 4.4 g of polydimethylsiloxane prepolymer SYLGARD 184A, 11 g of n-hexane, 4 g of perfluoropolyether oil, and 0.44 g of curing agent SYLGARD 184B, and stirred at 500 rpm for 0.5 h and then degassed under vacuum for 10 min to obtain the surface layer coating; 4.5 mL of octadecyltrichlorosilane was mixed with 0.09 mL of deionized water, ultrasonically dispersed at a power of 100 W for 5 min, then left to hydrolyze at 30 °C for 4 h, and then 45.4 mL of n-hexane was added and stirred at 500 rpm for 0.5 h to obtain the bottom layer coating containing silicone aggregates;

[0056] First, the power transmission line pretreated by grinding, polishing, and degreasing was soaked in the bottom layer coating for 30 min. After drying and curing at 60 °C for 1 h, under an air pressure of 0.4 MPa, maintaining a spraying distance of 20 cm and a spraying amount of 0.5 mL / cm 2 the surface layer coating was sprayed onto its surface. After heat curing treatment at 60 °C for 3 h, an anti-icing composite coating with a thickness of 40 μm was obtained.

[0057] Example 3

[0058] 10 mL of tetraethyl orthosilicate, 10 mL of ammonia water, 500 mL of ethanol, and 100 mL of deionized water were mixed and stirred for the first time at 200 rpm for 24 h. After adding 0.9 g of resorcinol and 2 mL of formaldehyde, it was stirred for the second time for 6 h. Then 16 mL of tetraethyl orthosilicate was added again and stirred for the third time for 20 h. Then it was hydrothermally treated at 90 °C for 15 h. Finally, it was centrifuged at 8000 rpm for 4 min and dried at 60 °C for 8 h to obtain the carbon vesicle precursor, namely silica@resorcinol formaldehyde resin-silica;

[0059] The carbon vesicle precursor was carbonized at 700 °C in a nitrogen atmosphere for 2 h. After cooling to room temperature, it was dispersed in a 2 mol / L sodium hydroxide solution and etched by stirring at a speed of 500 rpm for 8 h to remove the silica template. Subsequently, it was centrifuged at 10000 rpm for 3 min, washed with water three times, and dried at 80 °C for 10 h to obtain hollow nano-carbon vesicles (the hollow nano-carbon vesicles have a thin inner layer, a rough outer layer, and a nanoporous interlayer between the two, with an inner diameter of 120 nm, an outer diameter of 160 nm, the thickness of both the inner layer and the outer layer being 3 nm, and the thickness of the porous interlayer between the inner layer and the outer layer being 14 nm);

[0060] 0.1 g of the hollow nano-carbon vesicles was mixed with 4 g of polydimethylsiloxane prepolymer SYLGARD 184A, 10 g of ethyl acetate, 5.5 g of silicone oil, and 0.4 g of curing agent SYLGARD 184B, stirred at 400 rpm for 0.5 h, and then degassed under vacuum for 20 min to obtain the surface coating; 4 mL of octadecyltrichlorosilane was mixed with 0.08 mL of deionized water, ultrasonically dispersed at a power of 100 W for 5 min, allowed to stand and hydrolyze at 25 °C for 4 h, and then 46 mL of n-hexane was added and stirred at 400 rpm for 1 h to obtain the bottom coating containing siloxane aggregates;

[0061] First, the power transmission line pretreated by grinding, polishing, and degreasing was soaked in the bottom coating for 50 min, dried and cured at 50 °C for 1 h, and then, under an air pressure of 0.3 MPa, maintaining a spraying distance of 18 cm and a spraying amount of 0.4 mL / cm 2 the surface coating was sprayed onto its surface. After heat curing at 70 °C for 2 h, a 30-μm-thick anti-icing composite coating was obtained.

[0062] Example 4

[0063] 10 mL of tetraethyl orthosilicate, 10 mL of ammonia water, 500 mL of ethanol, and 100 mL of deionized water were mixed and stirred for the first time at 500 rpm for 24 h. 1 g of resorcinol and 2.2 mL of formaldehyde were added thereto and then stirred for the second time for 7 h. 15 mL of tetraethyl orthosilicate was added again and stirred for the third time for 20 h. Then, it was hydrothermally treated at 100 °C for 12 h. Finally, it was centrifuged at 8000 rpm for 5 min and dried at 60 °C for 12 h to obtain the carbon vesicle precursor, i.e., silica@resorcinol formaldehyde resin-silica;

[0064] The carbon vesicle precursor was carbonized at 800 °C in a nitrogen atmosphere for 1 h. After cooling to room temperature, it was dispersed in a 1 mol / L sodium hydroxide solution and stirred and etched at a speed of 600 rpm for 8 h to remove the silica template. Subsequently, it was centrifuged at 8000 rpm for 5 min, washed with water 4 times, and dried at 50 °C for 12 h to obtain hollow nano-carbon vesicles (the hollow nano-carbon vesicles have a thin inner layer, a rough outer layer, and a nanoporous interlayer between the two, with an inner diameter of 80 nm, an outer diameter of 120 nm, the thickness of both the inner layer and the outer layer being 3 nm, and the thickness of the porous interlayer between the inner layer and the outer layer being 14 nm);

[0065] 0.1 g of the hollow nano-carbon vesicles was mixed with 3.7 g of polydimethylsiloxane prepolymer SYLGARD 184A, 9.03 g of tetrahydrofuran, 6.8 g of perfluoropolyether oil, and 0.37 g of curing agent SYLGARD 184B, stirred at 300 rpm for 0.5 h, and then degassed under vacuum for 15 min to obtain a surface layer coating; 4.5 mL of octadecyltrichlorosilane was mixed with 0.09 mL of deionized water, ultrasonically dispersed at a power of 100 W for 3 min, left to hydrolyze at 25 °C for 3 h, then 45.4 mL of n-hexane was added, and it was stirred at 300 rpm for 1 h to obtain a bottom layer coating containing silicone aggregates;

[0066] First, the power transmission line pretreated by grinding, polishing, and degreasing was soaked in the bottom layer coating for 40 min, dried and cured at 50 °C for 40 min, and then, under an air pressure of 0.2 MPa, maintaining a spraying distance of 20 cm and a spraying amount of 0.4 mL / cm 2 the surface layer coating was sprayed onto its surface. After heat curing at 60 °C for 3 h, a 25-μm-thick anti-icing composite coating was obtained.

[0067] Example 5

[0068] 10 mL of tetraethyl orthosilicate, 5 mL of ammonia water, 125 mL of ethanol, and 50 mL of deionized water were mixed and stirred for the first time at 300 rpm for 24 h. After adding 0.4 g of resorcinol and 0.9 mL of formaldehyde, it was stirred for the second time for 5 h. Then, 13 mL of tetraethyl orthosilicate was added again and stirred for the third time for 25 h. Then, it was hydrothermally treated at 100 °C for 12 h. Finally, it was centrifuged at 8000 rpm for 5 min and dried at 60 °C for 10 h to obtain a carbon vesicle precursor, namely silica@resorcinol formaldehyde resin-silica;

[0069] The carbon vesicle precursor was carbonized in a nitrogen atmosphere at 800 °C for 1 h, cooled to room temperature, and then dispersed in a 1 mol / L sodium carbonate solution. It was stirred and etched at a speed of 400 rpm for 8 h to remove the silica template. Subsequently, it was centrifuged at 9000 rpm for 4 min, washed with water three times, and dried at 60 °C for 10 h to obtain hollow carbon nanovesicles (the hollow carbon nanovesicles have a thin inner layer, a rough outer layer, and a nanoporous interlayer between the two. The inner diameter is 105 nm, the outer diameter is 137 nm, the thickness of both the inner layer and the outer layer is 2 nm, and the thickness of the porous interlayer between the inner layer and the outer layer is 12 nm);

[0070] 0.1 g of the hollow carbon nanovesicles was mixed with 3.66 g of polydimethylsiloxane prepolymer SYLGARD 184A, 8.94 g of ethyl acetate, 6.94 g of ethyl oleate, and 0.36 g of curing agent SYLGARD 184B. After stirring at 300 rpm for 1 h, it was degassed under vacuum for 30 min to obtain the surface coating; 2.8 mL of octadecyltrichlorosilane was mixed with 0.056 mL of deionized water, ultrasonically dispersed at a power of 100 W for 4 min, then left to hydrolyze at 30 °C for 2 h, and then 47 mL of n - hexane was added, and it was stirred at 300 rpm for 1 h to obtain the bottom coating containing siloxane aggregates;

[0071] First, the bottom coating was used to soak the power transmission line pretreated by grinding, polishing, and degreasing for 30 min. After drying and curing at 60 °C for 0.5 h, under an air pressure of 0.4 MPa, maintaining a spraying distance of 15 cm and a spraying volume of 0.5 mL / cm 2 the surface coating was sprayed onto its surface. After heat - curing treatment at 70 °C for 3 h, an anti - icing composite coating with a thickness of 30 μm was obtained.

[0072] Table 1 shows the performance comparison of polysiloxane coatings, polysiloxane / graphene coatings, PDMS / multi - walled carbon nanotube / silicone oil coatings, and the anti - icing coatings prepared in Examples 1 and 2. It can be seen from the table that the polysiloxane coating has poor hydrophobicity. The ice - freezing delay time at - 10 °C is only 100 s, and the ice adhesion force is as high as 150 kPa, so the anti - icing effect is not good; the polysiloxane / graphene coating has superhydrophobicity, can delay ice formation, and can also de - ice by photothermal effect, but the coating stability is very poor; the PDMS / multi - walled carbon nanotube / silicone oil coating has a very low ice adhesion force, and can also generate heat for de - icing by photothermal reaction, but the anti - icing effect decreases significantly after the silicone oil is lost. Compared with the above coatings, the coatings prepared in Examples 1 and 2 of this embodiment have super - slipperiness and superhydrophobicity, can significantly delay ice formation, greatly reduce the ice adhesion force, and make full use of solar heat to melt ice, with an excellent long - term anti - icing effect. In addition, even after long - term use, when the lubricant is exhausted, the exposed superhydrophobic surface still has excellent ice - repellency and excellent stability.

[0073] Table 1 Performance Comparison between Existing Anti-Icing Coatings and the Highly Durable Anti-Icing Composite Coatings Prepared in the Examples

[0074]

[0075] Although the specific embodiments of the present invention have been described above, those skilled in the art should understand that this is only for illustration purposes. The protection scope of the present invention is defined by the appended claims. Without departing from the principles and essence of the present invention, those skilled in the art can make various changes or modifications to these embodiments, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A preparation method of an anti-icing coating on the surface of a transmission line, characterized in that, it is specifically implemented according to the following steps: Step 1, prepare carbon vesicle precursors: Mix tetraethyl orthosilicate, ammonia water, ethanol and deionized water and conduct the first stirring, then add resorcinol and formaldehyde thereto and conduct the second stirring, add tetraethyl orthosilicate again and conduct the third stirring, then conduct hydrothermal treatment, and finally obtain carbon vesicle precursors, namely silica@resorcinol formaldehyde resin-silica, through centrifugation and drying; Step 2, carbonization treatment and template removal: Carbonize the carbon vesicle precursors obtained in Step 1 under a nitrogen atmosphere, disperse them into an alkali solution after cooling to room temperature and conduct stirring and etching to remove the silica template, then conduct centrifugation, water washing and drying to obtain hollow nano-carbon vesicles; Step 3, prepare the surface coating and the bottom coating: Mix the hollow nano-carbon vesicles obtained in Step 2 with a polydimethylsiloxane prepolymer, a solvent, a lubricant and a curing agent, stir evenly and degas under vacuum to obtain the surface coating; Mix octadecyltrichlorosilane with deionized water, conduct ultrasonic dispersion, then conduct hydrolysis at a constant temperature and static standing, and add n-hexane and stir evenly to obtain the bottom coating containing siloxane aggregates; Step 4, prepare the anti-icing composite coating: Soak the pretreated transmission line with the bottom coating obtained in Step 3, and after drying and curing, form a bottom coating on the surface of the transmission line substrate; spray the surface coating on the surface of the transmission line with the bottom coating, and after heat curing treatment, obtain the anti-icing composite coating.

2. The preparation method of an anti-icing coating on the surface of a transmission line according to claim 1, characterized in that, the mass percentages of the initially added tetraethyl orthosilicate, ammonia water, ethanol, deionized water, resorcinol, formaldehyde and the secondarily added tetraethyl orthosilicate in Step 1 are respectively 1.8% - 6.8%, 1.7% - 3.3%, 71.7% - 74.8%, 12.7% - 19%, 0.2% - 0.3%, 0.4% - 0.8% and 2.1% - 4.4%, and the sum of the above components is 100%; the stirring speed is 200 - 500 rpm, the first stirring time is 20 - 24 h, the second stirring time is 5 - 7 h, the third stirring time is 20 - 30 h; the hydrothermal temperature is 90 - 100 °C, the hydrothermal time is 12 - 15 h; the centrifugation speed is 6000 - 8000 rpm, the centrifugation time is 3 - 5 min; the drying temperature is 50 - 60 °C, the drying time is 8 - 12 h.

3. The preparation method of an anti-icing coating on the surface of a transmission line according to claim 1, characterized in that, in Step 2, the carbonization temperature is 700 - 800 °C, the carbonization time is 1 - 2 h, the alkali solution is any one of sodium hydroxide solution and sodium carbonate solution, the concentration of the alkali solution is 0.6 - 2 mol / L, the stirring speed is 400 - 600 rpm, the etching time is 6 - 12 h, the centrifugation speed is 8000 - 10000 rpm, the centrifugation time is 3 - 5 min, the number of water washing times is 3 - 4 times, the drying temperature is 50 - 80 °C, the drying time is 8 - 12 h.

4. The preparation method of an anti-icing coating on the surface of a power transmission line according to claim 1, characterized in that, in step 3, the surface layer coating is composed of the following substances by mass percentage: 0.5-0.7% of hollow nano-carbon vesicles, 18.3-22% of polydimethylsiloxane prepolymer, 44.7-55% of solvent, 20.1-34.7% of lubricant and 1.8-2.2% of curing agent. The sum of the above components is 100%. The polydimethylsiloxane prepolymer is SYLGARD 184A, the curing agent is SYLGARD 184B, the solvent is any one of xylene, ethyl acetate, n-hexane and tetrahydrofuran, the lubricant is one of silicone oil, ethyl oleate and perfluoropolyether oil, the stirring speed is 300-500 rpm, the stirring time is 0.5-1 h, and the degassing time is 10-30 min.

5. The preparation method of an anti-icing coating on the surface of a power transmission line according to claim 1, characterized in that, in step 3, the bottom layer coating is composed of the following substances by mass percentage: 5.6-9% of octadecyltrichlorosilane, 0.1-0.2% of deionized water, 90.8-94.3% of n-hexane. The sum of the above components is 100%. The ultrasonic power is 100 W, the ultrasonic time is 3-5 min, the hydrolysis temperature is 25-30 °C, the hydrolysis time is 2-4 h, the stirring speed is 300-500 rpm, and the stirring time is 0.5-1 h.

6. The preparation method of an anti-icing coating on the surface of a power transmission line according to claim 1, characterized in that, In the said step 4, the pre-treatment of the transmission line includes sandpaper grinding, polishing and degreasing. The soaking time is 30 to 60 minutes, the drying temperature is 50 to 60 °C, the drying time is 0.5 to 1 hour. The spraying equipment provides air pressure through an air compressor, the air pressure is 0.2 to 0.4 MPa, the spraying distance is 15 to 20 cm, and the spraying volume is 0.4 to 0.5 mL / cm 2 , the thermal curing temperature is 60 to 70 °C, and the thermal curing time is 2 to 3 hours.

7. The anti-icing coating on the surface of a power transmission line prepared by the preparation method of an anti-icing coating on the surface of a power transmission line according to any one of claims 1-6, characterized in that, it includes a bottom layer composed of micro-nano porous silica aggregates and a surface layer composed of a lubricant and hollow nano-carbon vesicles that are sequentially attached to the surface of the power transmission line substrate from the inside to the outside. Among them, the hollow nano-carbon vesicles have an inner layer, an outer layer and a sandwich layer between the two. The inner diameter of the hollow nano-carbon vesicles is 80-120 nm, the outer diameter is 120-160 nm, the thickness of both the inner layer and the outer layer is 2-3 nm, the thickness of the sandwich layer between the inner layer and the outer layer is 10-14 nm, and the thickness of the anti-icing composite coating is 20-40 μm.

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