A method for preparing a photothermal superhydrophobic coating with excellent anti-icing / deicing performance in low temperature and high relative humidity environments

Abstract

The present invention discloses a preparation method of a photothermal super-hydrophobic coating with excellent anti-icing / de-icing performance under a low temperature and high relative humidity environment, first by in situ growth of photothermal Cu-MOF nanoparticles on the surface of low thermal conductivity fibrous clay mineral nanoparticles, constructing a two-level nano- / nano-structured composite photothermal particle, which is then subjected to low surface energy modification and introduced into a low thermal conductivity binder, and a binder is induced to phase separate to form a micron-scale binder / low surface energy nanoparticle aggregate by a non-solvent, and finally a photothermal super-hydrophobic coating with a three-level micro- / nano- / nano-structure is constructed by spraying. The three-level micro- / nano- / nano-structure of the coating simultaneously gives the coating excellent photothermal performance and the Cassie-Baxter state stability of the droplet on the coating surface under a low temperature and high relative humidity environment, so that it has excellent passive anti-icing / frosting and active de-icing / defrosting performance in this environment. The low thermal conductivity of the coating further suppresses the heat exchange between the substrate-water droplets, so that the passive anti-icing / frosting performance of the coating is further improved. In addition, the present invention has the advantages of simple preparation method and large-area preparation, laying a solid foundation for the practical application of photothermal superhydrophobic anti-icing coatings.

Description

Technical Field

[0001] The present invention relates to a method for preparing a photothermal super-hydrophobic coating, and in particular to a method for preparing a photothermal super-hydrophobic coating with excellent anti-icing / de-icing performance in a low-temperature, high relative humidity environment, belonging to the technical field of super-hydrophobic anti-icing coating preparation. Background Art

[0002] Surface icing poses a serious threat to the safety and reliability of the operation of new energy facilities and leads to huge economic losses. Traditional de-icing methods, such as mechanical vibration and heat treatment, usually require a lot of manpower and material resources, and have low de-icing efficiency. In recent years, researchers have gradually turned their attention to passive anti-icing strategies, which are popular due to their high efficiency and low cost. To date, superhydrophobic coatings have become one of the most promising passive anti-icing solutions. Their excellent performance is mainly due to their high contact angle (>150°) and low rolling angle (<10°), which effectively reduces the contact area between solid and liquid, thereby delaying the formation of ice and reducing the adhesion strength of ice.

[0003] However, super-hydrophobic coatings can only delay ice formation, but cannot completely prevent ice formation. Therefore, photothermal super-hydrophobic coatings that combine passive anti-icing and active de-icing functions are gradually becoming an effective anti-icing and de-icing material. Patent CN109486269A prepares a photothermal super-hydrophobic coating with passive anti-icing and active de-icing properties by spraying a low surface energy silicon micropowder / carbon nanotube dispersion on the surface of a substrate. Patent CN115260897B synthesizes polydimethylsiloxane microspheres with photothermal properties by emulsion polymerization and disperses them in a low surface energy silica nanoparticle dispersion, which is then sprayed onto a semi-dried fluorocarbon resin surface to prepare a photothermal super-hydrophobic passive anti-icing / active de-icing coating.

[0004] Although significant progress has been made in the research of photothermal superhydrophobic passive anti-icing / active deicing coatings, the following problems still exist in practical applications: (1) The passive anti-icing performance of the coating is insufficient in low temperature and high relative humidity environments. This is because: i) in this environment, it is difficult for the droplets to maintain a stable Cassie-Baxter state on the coating surface, resulting in a sharp drop in anti-icing performance; ii) although the superhydrophobic coating can effectively reduce the contact area between the coating and the water droplets to inhibit heat exchange, it cannot be completely avoided, resulting in insufficient passive anti-icing performance of the coating. (2) Most photothermal superhydrophobic coatings show excellent performance under a light intensity of 1 sun, but the photothermal performance of the coating is insufficient in low temperature and high relative humidity environments, resulting in a sharp drop in its active deicing performance.

[0005] Therefore, the present invention, by adopting low thermal conductivity raw materials and simple spraying process, builds a low thermal conductivity photothermal super hydrophobic coating with three-level micro / nano / nano structure on the surface of various substrates.Specific as follows: first, by in situ growth photothermal Cu-MOF nanoparticles on the surface of low thermal conductivity fibrous clay mineral nanomaterial, build a two-level nano / nano structure of composite photothermal particles, which is then subjected to low surface energy modification and introduces a low thermal conductivity binder, and a binder is induced to phase separate to form a micron-sized binder / low surface energy nanoparticle aggregate by a non-solvent-induced binder, and finally a coating with three-level micro / nano / nano structure is built by spraying. The three-level micro / nano / nano structure of the coating not only gives the coating excellent photothermal performance under low temperature, high relative humidity environment, but also improves the Cassie-Baxter state stability of the droplet on the coating surface under the environment, so that it has excellent passive anti-icing / frosting, active deicing / defrosting performance under low temperature, high relative humidity environment. Furthermore, the coating's low thermal conductivity further inhibits heat exchange between the substrate and the water droplets, further enhancing the coating's passive anti-icing / frosting performance. The photothermal superhydrophobic coating prepared by this invention effectively addresses the shortcomings of traditional (photothermal) superhydrophobic anti-icing coatings and is of great significance for their practical application. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preparing a photothermal super-hydrophobic coating with excellent anti-icing / de-icing performance in a low temperature and high relative humidity environment, which can effectively solve the problems existing in the practical application of current photothermal super-hydrophobic coatings.

[0007] 1. Preparation of photothermal superhydrophobic coating

[0008] The photothermal super-hydrophobic coating of the present invention is composed of a low thermal conductivity binder and low surface energy Cu-MOF@fibrous composite nanoparticles. The specific preparation method is as follows:

[0009] (1) Preparation of Cu-MOF@fibrous composite nanoparticles: Copper nitrate and 2,3,6,7,10,11-hexahydroxytriphenylenebenzene (HHTP) were dissolved in a mixed solvent of N,N-dimethylformamide / water. After stirring for 3-8 minutes, low thermal conductivity fibrous clay mineral nanoparticles were added. The mixture was stirred at 80-90°C for 10-15 hours. The resulting suspension was filtered, washed, dried, and ground to obtain Cu-MOF@fibrous composite nanoparticles with a two-level nano / nano structure.

[0010] The concentration of the copper nitrate in the N,N-dimethylformamide / water mixture is 8-12 mg / mL; the concentration of the HHTP in the N,N-dimethylformamide / water mixture is 5-7 mg / mL; the volume ratio of N,N-dimethylformamide to water in the N,N-dimethylformamide / water mixture is 1:10. The low thermal conductivity fibrous clay mineral nanoparticles are selected from attapulgite, halloysite, and sepiolite; the concentration of the low thermal conductivity fibrous clay mineral nanoparticles in the N,N-dimethylformamide / water mixture is 15-40 mg / mL.

[0011] (2) Preparation of low surface energy Cu-MOF@fibrous composite nanoparticles: The Cu-MOF@fibrous composite nanoparticles prepared in (1) were dispersed in ethanol, stirred for 8-12 minutes, and then ultrasonically dispersed for 4-6 minutes. Ammonia water was then added and stirred for 4-6 minutes, followed by adding fluorosilane. Fluorosilane was allowed to undergo hydrolysis and condensation reaction on the surface of the Cu-MOF@fibrous composite nanoparticles at room temperature. Finally, the obtained suspension was centrifuged, dried, and pulverized to obtain low surface energy Cu-MOF@attapulgite composite nanoparticles.

[0012] The concentration of the Cu-MOF@fibrous composite nanoparticles in the reaction system was 5-15 mg / mL; the volume ratio of ethanol to ammonia was 49:1-40:10; the fluorosilane was one of perfluorooctyltriethoxysilane and perfluorodecyltriethoxysilane, and the mass ratio of fluorosilane to Cu-MOF@fibrous composite nanoparticles was 1:1-2:1; and the hydrolysis-condensation reaction time was 2-4 hours.

[0013] (3) Preparation of photothermal superhydrophobic coating dispersion: First, a low thermal conductivity binder is dissolved in an organic solvent, and then a non-solvent is added dropwise under stirring at room temperature to cause non-solvent-induced phase separation. Then, the low surface energy Cu-MOF@fibrous composite nanoparticles prepared in (2) are added, stirred for 2-4 hours and ultrasonicated for 20-40 minutes to form a low thermal conductivity binder / low surface energy Cu-MOF@fibrous composite nanoparticle microaggregate dispersion (photothermal superhydrophobic coating dispersion);

[0014] The low thermal conductivity binder is at least one of hydroxyl-terminated polybutadiene and hydroxyl-terminated polyisoprene; the mass fraction of the low thermal conductivity binder in the reaction system is 5% to 15%.

[0015] The organic solvent is at least one of methyl acetate, ethyl acetate, dimethyl carbonate, and butyl acetate; the non-solvent is at least one of methanol, ethanol, and isopropanol; the mass ratio of solvent to non-solvent is 1:1 to 3:1. The mass fraction of the low-surface-energy Cu-MOF@fibrous composite nanoparticles in the reaction system is 6% to 10%.

[0016] (4) Preparation of photothermal superhydrophobic coating: Add curing agent isophorone diisocyanate and catalyst dibutyltin dilaurate to the dispersion prepared in (3) in sequence, stir for 8-12 minutes, spray onto the substrate, and cure at room temperature for 70-75 hours to obtain a low thermal conductivity photothermal superhydrophobic coating with a three-level micro / nano / nano structure.

[0017] The mass ratio of the curing agent isophorone diisocyanate to the low thermal conductivity binder is 1:9 to 1:11, and the mass ratio of the catalyst dibutyltin dilaurate to the low thermal conductivity binder is 1:90 to 1:110. The substrate includes aluminum alloy, magnesium alloy, glass, stainless steel, PP, and ABS.

[0018] SEM images of photothermal super hydrophobic coatings are shown in Figure 2. Figure 1 Low-magnification SEM images reveal a distinct hierarchical micro / nanostructure of the coating, primarily due to the phase separation of the low thermal conductivity binder into microparticles and the encapsulation of low-surface-energy Cu-MOF@fibrous composite nanoparticles on their surface. High-magnification SEM images reveal a two-level nano / nanostructure composed of Cu-MOF nanoparticles and fibrous clay mineral nanoparticles. Therefore, the coating possesses a three-level micro / nano / nanostructure.

[0019] The present invention first grows photothermal Cu-MOF nanoparticles in situ on the surface of low thermal conductivity fibrous clay mineral nanoparticles, constructs a two-level nano / nano structure of composite photothermal particles, which is then subjected to low surface energy modification and introduced into a low thermal conductivity binder, and the binder is induced to phase separate by a non-solvent to form a micron-scale binder / low surface energy nanoparticle aggregate, and finally a photothermal super-hydrophobic coating with a three-level micro / nano / nano structure is constructed by spraying. The three-level micro / nano / nano structure of the coating simultaneously gives the coating excellent photothermal performance and Cassie-Baxter state stability of the droplets on the coating surface under low temperature and high relative humidity environments, so that it has excellent passive anti-icing / frosting and active deicing / defrosting performance in this environment. The low thermal conductivity of the coating further suppresses the heat exchange between the substrate and the water droplets, so that the passive anti-icing / frosting performance of the coating is further improved. In addition, the present invention also has the advantages of simple preparation method and large-scale preparation, which lays a solid foundation for the practical application of the photothermal super-hydrophobic anti-icing coating.

[0020] 2. Performance of Photothermal Super-Hydrophobic Coating

[0021] (1) Superhydrophobicity

[0022] The coating prepared by the present invention has excellent superhydrophobicity at room temperature, low temperature and high relative humidity environment:

[0023] At room temperature, the contact angle (CA) of a 10μL water droplet is >165°, and the sliding angle (SA) is <1°; the CA of a 1μL water droplet is >160°, and the SA is <10° ( Figure 2 );

[0024] Under -10℃ and 80% relative humidity, the SA of 10μL water droplet is less than 15° ( Figure 3 );

[0025] Under -20℃ and 80% relative humidity, the SA of 10μL water droplet is less than 30° ( Figure 3 ).

[0026] (2) Photothermal performance

[0027] The coating prepared by the present invention has excellent photothermal properties at room temperature, low temperature and high relative humidity environments:

[0028] At room temperature and 1 sun intensity, the surface temperature of the coating can rise to over 100°C within 8 minutes ( Figure 4 a);

[0029] Under the conditions of -10℃, 80% relative humidity and 0.1 sun intensity, the temperature of the coating surface can rise to above 9℃ within 8 minutes ( Figure 4 b).

[0030] (3) Passive anti-icing performance

[0031] The coating prepared by the present invention exhibits excellent static and dynamic passive anti-icing performance in low temperature and high relative humidity environments:

[0032] Static passive anti-icing performance: Under -10℃ and 80% relative humidity, a 60μL water droplet remained unfrozen on the coating surface after 1 hour ( Figure 5 a); Also in this environment, the ice adhesion strength of the coating is <20kPa ( Figure 5 b) Under -10℃, 80% relative humidity and 0.1 solar light intensity, a 60μL water droplet did not freeze after 5 hours on the coating surface.

[0033] Dynamic passive anti-icing performance: At -10°C and 80% relative humidity, 60μL supercooled water droplets continuously fall onto the coating surface (40-50 drops / min). After 2 hours, there is no ice accumulation on the coating surface.

[0034] (4) Passive anti-frost performance

[0035] The passive anti-frost performance of the coating was studied by spraying cold water mist (0°C, 1.67g / min) from a humidifier in a -10°C environment. The results showed that after a 1-hour frost test in this environment, only a small amount of frost (~0.5mg / cm2) formed on the surface of the coating. 2 )( Figure 5 c) Under the conditions of -10℃ and 0.1 sun intensity, after a 3-hour frosting test, no frost is formed on the surface of the coating.

[0036] (5) Active de-icing performance

[0037] Under the conditions of -10℃, 80% relative humidity and 0.1 sun intensity, when the coating is tilted 15°, a 60μL frozen water droplet on its surface melts and rolls off within 3 minutes ( Figure 6 a); Under the same conditions, the ice (thickness 1mm) on the coating surface can melt and fall off within 45 minutes ( Figure 6 b).

[0038] (6) Active defrosting performance

[0039] At -10℃, 80% relative humidity, and 0.1 sun intensity, the frost (~1mm thick) on the coating surface melted within 10 minutes when the coating was tilted 15°. Figure 6 c).

[0040] In summary, compared with the prior art, the present invention has the following advantages:

[0041] The coating's low-surface-energy, three-level micro / nano / nanostructure design not only imparts excellent photothermal performance (at both room and low temperatures), but also significantly enhances the stability of the Cassie-Baxter state of droplets on the coating surface in low-temperature, high-relative-humidity environments. This effectively improves the coating's passive anti-icing and active de-icing performance in these environments, resolving the practical limitations of traditional photothermal super-hydrophobic anti-icing coatings. Furthermore, the synergistic effect of the low thermal conductivity of the raw material and the extremely low solid-liquid contact area of ​​the super-hydrophobic coating almost completely suppresses heat exchange between the droplets and the substrate, further enhancing the coating's passive anti-icing and de-icing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 This is an SEM image of the photothermal super-hydrophobic coating of the present invention.

[0043] Figure 2 a is the CA of 10 μL and 1 μL water droplets on the photothermal superhydrophobic coating of the present invention; Figure 2 b is the SA of 10 μL and 1 μL water droplets on the photothermal superhydrophobic coating of the present invention.

[0044] Figure 3 SA is a 10 μL water droplet on the photothermal superhydrophobic coating of the present invention under low temperature and 80% relative humidity environment.

[0045] Figure 4 a is the change in temperature of the aluminum alloy and the surface of the photothermal super-hydrophobic coating of the present invention over time under room temperature and 1 sun intensity environment; Figure 4 b is the change in temperature over time of the surface of the aluminum alloy and the photothermal superhydrophobic coating of the present invention at -10°C, 80% relative humidity, and 0.1 sun intensity.

[0046] Figure 5 a is the freezing time of a 60 μL water droplet on the surface of the aluminum alloy and the photothermal superhydrophobic coating of the present invention under an environment of -10°C and 80% relative humidity; Figure 5 b is the adhesion strength of ice on the surfaces of the aluminum alloy and the photothermal super-hydrophobic coating of the present invention under an environment of -10°C and 80% relative humidity; Figure 5 c is the amount of frost accumulated on the surface of the aluminum alloy and the photothermal super-hydrophobic coating of the present invention after a 1-h frosting test at -10°C.

[0047] Figure 6 a is the deicing time of a 60 μL frozen water droplet on the surface of the aluminum alloy and the photothermal superhydrophobic coating of the present invention under an environment of -10°C, 80% relative humidity, and 0.1 sun intensity; Figure 6 b is the deicing time of a 1 mm ice layer on the surface of the aluminum alloy and the photothermal superhydrophobic coating of the present invention under an environment of -10°C, 80% relative humidity, and 0.1 sun intensity; Figure 6 c is the defrosting time of a 1 mm frost layer on the surface of the aluminum alloy and the photothermal superhydrophobic coating of the present invention under an environment of -10°C, 80% relative humidity, and 0.1 sun intensity. DETAILED DESCRIPTION

[0048] The preparation and performance of the photothermal super-hydrophobic coating of the present invention are further described below through specific examples.

[0049] Example 1

[0050] ① 9.7g of copper nitrate and 6.5g of HHTP were dissolved in 1L of a mixture of N,N-dimethylformamide and water (v / v = 1 / 10). After stirring for 5 minutes, 25g of attapulgite nanoparticles were added and stirred continuously at 85°C for 15 hours (500 rpm). The resulting suspension was then filtered, washed, dried, and ground to produce Cu-MOF@attapulgite composite nanoparticles with a two-level nano / nano structure. ② 5g of Cu-MOF@attapulgite composite nanoparticles were dispersed in 440mL of ethanol, stirred for 10 minutes, and then ultrasonically dispersed for 5 minutes. 60mL of ammonia was then added, stirred for 5 minutes, and 7g of perfluorodecyltriethoxysilane was added. The mixture was reacted at room temperature for 2 hours. The resulting suspension was centrifuged, dried, and ground to produce low-surface-energy Cu-MOF@attapulgite composite nanoparticles. ③ 7.5 g of hydroxyl-terminated polybutadiene binder was dissolved in 60 g of butyl acetate. Subsequently, 29 g of ethanol was added dropwise with stirring at room temperature to induce non-solvent-induced phase separation, forming hydroxyl-terminated polybutadiene binder microaggregates. Then, 7.9 g of low-surface-energy Cu-MOF@attapulgite composite nanoparticles were added. After stirring for 3 h and assisted ultrasonic dispersion for 30 min, a hydroxyl-terminated polybutadiene binder / low-surface-energy Cu-MOF@attapulgite composite nanoparticle microaggregate dispersion was prepared. ④ 0.75 g of isophorone diisocyanate and 0.075 g of dibutyltin dilaurate were added to the hydroxyl-terminated polybutadiene binder / low-surface-energy Cu-MOF@attapulgite composite nanoparticle microaggregate dispersion, stirred for 10 min, and then sprayed onto an aluminum alloy substrate. The coating was cured at room temperature for 72 h, resulting in a low-thermal-conductivity photothermal superhydrophobic coating with a three-level micro / nano / nanostructure. The coating properties are shown in Table 1.

[0051] Example 2

[0052] ① 9.5g of copper nitrate and 6.9g of HHTP were dissolved in 1L of a mixed solvent of N,N-dimethylformamide / water (v / v = 1 / 10). After stirring for 5 minutes, 20g of halloysite nanoparticles were added and stirred continuously at 85°C for 15 hours (500 rpm). The resulting suspension was then filtered, washed, dried, and ground to produce Cu-MOF@halloysite composite nanoparticles with a two-level nano / nano structure. ② 5.5g of Cu-MOF@halloysite composite nanoparticles were dispersed in 460mL of ethanol, stirred for 10 minutes, and then ultrasonically dispersed for 5 minutes. 40mL of ammonia was then added, stirred for 5 minutes, and 8.4g of perfluorooctyltriethoxysilane was added. The mixture was allowed to react at room temperature for 4 hours. The resulting suspension was centrifuged, dried, and ground to produce low-surface-energy Cu-MOF@halloysite composite nanoparticles. ③ 6.8 g of hydroxyl-terminated polybutadiene binder was dissolved in 60 g of dimethyl carbonate. 24 g of ethanol was then added dropwise with stirring at room temperature, causing non-solvent-induced phase separation to form hydroxyl-terminated polybutadiene binder microaggregates. 8.5 g of low-surface-energy Cu-MOF@halloysite composite nanoparticles were then added. The mixture was stirred for 3 h and subjected to ultrasonic dispersion for 30 min to prepare a hydroxyl-terminated polybutadiene binder / low-surface-energy Cu-MOF@halloysite composite nanoparticle microaggregate dispersion. ④ 0.7 g of isophorone diisocyanate and 0.07 g of dibutyltin dilaurate were added to the hydroxyl-terminated polybutadiene binder / low-surface-energy Cu-MOF@halloysite composite nanoparticle microaggregate dispersion, stirred for 10 min, and then sprayed onto a PP substrate. The mixture was cured at room temperature for 72 h, resulting in a low-thermal-conductivity photothermal superhydrophobic coating with a three-level micro / nano / nanostructure. The coating properties are shown in Table 2.

[0053] Example 3

[0054] ① 9.1g of copper nitrate and 6.2g of HHTP were dissolved in 1L of a mixed solvent of N,N-dimethylformamide and water (v / v = 1 / 10). After stirring for 5 minutes, 28g of sepiolite nanoparticles were added and stirred continuously at 85°C for 15 hours (500 rpm). The resulting suspension was then filtered, washed, dried, and ground to produce Cu-MOF@sepiolite composite nanoparticles with a two-level nano / nano structure. ② 5.6g of Cu-MOF@sepiolite composite nanoparticles were dispersed in 440mL of ethanol, stirred for 10 minutes, and then ultrasonically dispersed for 5 minutes. 60mL of ammonia was then added, stirred for 5 minutes, and 9.8g of perfluorodecyltriethoxysilane was added. The mixture was allowed to react at room temperature for 3 hours. The resulting suspension was centrifuged, dried, and ground to produce low-surface-energy Cu-MOF@sepiolite composite nanoparticles. ③ 7g of hydroxyl-terminated polybutadiene binder was dissolved in 60g of methyl acetate. 24g of ethanol was then added dropwise with stirring at room temperature, causing non-solvent-induced phase separation to form hydroxyl-terminated polybutadiene binder microaggregates. Then, 7.1g of low-surface-energy Cu-MOF@attapulgite composite nanoparticles was added. After stirring for 3h and assisted ultrasonic dispersion for 30min, a hydroxyl-terminated polybutadiene binder / low-surface-energy Cu-MOF@sepiolite composite nanoparticle microaggregate dispersion was prepared. ④ 0.7g of isophorone diisocyanate and 0.07g of dibutyltin dilaurate were added to the hydroxyl-terminated polybutadiene binder / low-surface-energy Cu-MOF@sepiolite composite nanoparticle microaggregate dispersion, stirred for 10min, and then sprayed onto an ABS substrate. The coating was cured at room temperature for 72h, resulting in a low-thermal-conductivity photothermal superhydrophobic coating with a three-level micro / nano / nanostructure. The coating properties are shown in Table 3.

[0055] Example 4

[0056] ① 9.7g of copper nitrate and 6.5g of HHTP were dissolved in 1L of a mixture of N,N-dimethylformamide and water (v / v = 1 / 10). After stirring for 5 minutes, 25g of attapulgite nanoparticles were added and stirred continuously at 85°C for 15 hours (500 rpm). The resulting suspension was then filtered, washed, dried, and ground to produce Cu-MOF@attapulgite composite nanoparticles with a two-level nano / nano structure. ② 5g of Cu-MOF@attapulgite composite nanoparticles were dispersed in 440mL of ethanol, stirred for 10 minutes, and then ultrasonically dispersed for 5 minutes. 60mL of ammonia was then added, stirred for 5 minutes, and 7g of perfluorodecyltriethoxysilane was added. The mixture was reacted at room temperature for 2 hours. The resulting suspension was centrifuged, dried, and ground to produce low-surface-energy Cu-MOF@attapulgite composite nanoparticles. ③ 7.3 g of hydroxyl-terminated polyisoprene binder was dissolved in 60 g of butyl acetate. Subsequently, 23 g of ethanol was added dropwise with stirring at room temperature, causing non-solvent-induced phase separation to form hydroxyl-terminated polybutadiene binder microaggregates. Then, 8.3 g of low-surface-energy Cu-MOF@attapulgite composite nanoparticles were added. After stirring for 3 hours and assisted ultrasonic dispersion for 30 minutes, a hydroxyl-terminated polyisoprene binder / low-surface-energy Cu-MOF@attapulgite composite nanoparticle microaggregate dispersion was prepared. ④ 0.73 g of isophorone diisocyanate and 0.073 g of dibutyltin dilaurate were added to the hydroxyl-terminated polyisoprene binder / low-surface-energy Cu-MOF@attapulgite composite nanoparticle microaggregate dispersion, stirred for 10 minutes, and then sprayed onto a glass substrate. The mixture was cured at room temperature for 72 hours, resulting in a low-thermal-conductivity photothermal superhydrophobic coating with a three-level micro / nano / nanostructure. The coating properties are shown in Table 4.

[0057]

[0058]

[0059]

[0060]

Claims

1. A method for preparing a photothermal super-hydrophobic coating with excellent anti-icing / de-icing performance in a low temperature and high relative humidity environment, comprising the following process steps: (1) Preparation of Cu-MOF@fibrous composite nanoparticles: Copper nitrate and 2,3,6,7,10,11-hexahydroxytriphenylenebenzene were dissolved in a mixed solvent of N,N-dimethylformamide / water, stirred for 3-8 minutes, and then low thermal conductivity fibrous clay mineral nanoparticles were added. The mixture was stirred at 80-90°C for 10-15 hours. The resulting suspension was filtered, washed, dried, and ground to obtain Cu-MOF@fibrous composite nanoparticles with a two-level nano / nano structure. The low thermal conductivity fibrous clay mineral nanoparticles were selected from attapulgite, halloysite, and sepiolite. The concentration of the low thermal conductivity fibrous clay mineral nanoparticles in the mixed solvent of N,N-dimethylformamide / water was 15-40 mg / mL. (2) Preparation of low surface energy Cu-MOF@fibrous composite nanoparticles: The Cu-MOF@fibrous composite nanoparticles prepared in (1) were dispersed in ethanol, stirred for 8-12 minutes, and then ultrasonically dispersed for 4-6 minutes. Ammonia water was then added and stirred for 4-6 minutes. Fluorosilane was then added to allow hydrolysis and condensation of the fluorosilane on the surface of the Cu-MOF@fibrous composite nanoparticles at room temperature. Finally, the resulting suspension was centrifuged, dried, and pulverized to obtain low surface energy Cu-MOF@fibrous composite nanoparticles. (3) Preparation of photothermal superhydrophobic coating dispersion: First, a low thermal conductivity binder is dissolved in an organic solvent, and then a non-solvent is added dropwise under stirring at room temperature to cause non-solvent-induced phase separation, and then the low surface energy Cu-MOF@fibrous composite nanoparticles prepared in (2) are added, stirred for 2-4 hours and ultrasonicated for 20-40 minutes to form a low thermal conductivity binder / low surface energy Cu-MOF@fibrous composite nanoparticle microaggregate dispersion; the low thermal conductivity binder is at least one of end-hydroxyl polybutadiene and end-hydroxyl polyisoprene; the mass fraction of the low thermal conductivity binder in the reaction system is 5%-15%; (4) Preparation of photothermal superhydrophobic coating: Add curing agent isophorone diisocyanate and catalyst dibutyltin dilaurate to the dispersion prepared in (3) in sequence, stir for 8-12 minutes, spray onto the substrate, and cure at room temperature for 70-75 hours to obtain a low thermal conductivity photothermal superhydrophobic coating with a three-level micro / nano / nano structure.

2. The method for preparing a photothermal super-hydrophobic coating having excellent anti-icing / de-icing performance under a low temperature and high relative humidity environment as claimed in claim 1, wherein: In step (1), the concentration of the copper nitrate in the N,N-dimethylformamide / water mixed solvent is 8-12 mg / mL; the concentration of the 2,3,6,7,10,11-hexahydroxytriphenylene benzene in the N,N-dimethylformamide / water mixed solvent is 5-7 mg / mL; and in the N,N-dimethylformamide / water mixed solvent, the volume ratio of N,N-dimethylformamide to water is 1:

10.

3. The method for preparing a photothermal super-hydrophobic coating having excellent anti-icing / de-icing performance under a low temperature and high relative humidity environment as claimed in claim 1, wherein: In step (2), the volume ratio of ethanol to ammonia water is 49:1~40:10; the fluorosilane is one of perfluorooctyltriethoxysilane and perfluorodecyltriethoxysilane, and the mass ratio of fluorosilane to Cu-MOF@fibrous composite nanoparticles is 1:1~2:1; and the hydrolysis condensation reaction time is 2~4h.

4. The method for preparing a photothermal super-hydrophobic coating having excellent anti-icing / de-icing performance under a low temperature and high relative humidity environment as claimed in claim 1, wherein: In step (3), the organic solvent is at least one of methyl acetate, ethyl acetate, dimethyl carbonate, and butyl acetate; the non-solvent is at least one of methanol, ethanol, and isopropanol; and the mass ratio of the solvent to the non-solvent is 1:1 to 3:

1.

5. The method for preparing a photothermal super-hydrophobic coating having excellent anti-icing / de-icing performance under a low temperature and high relative humidity environment as claimed in claim 1, characterized in that: In step (3), the mass fraction of the low surface energy Cu-MOF@fibrous composite nanoparticles in the reaction system is 6% to 10%.

6. The method for preparing a photothermal super-hydrophobic coating having excellent anti-icing / de-icing performance under a low temperature and high relative humidity environment as claimed in claim 1, characterized in that: In step (4), the mass ratio of the curing agent isophorone diisocyanate to the low thermal conductivity adhesive is 1:9 to 1:11; the mass ratio of the catalyst dibutyltin dilaurate to the low thermal conductivity adhesive is 1:90 to 1:

110.

7. The method for preparing a photothermal superhydrophobic coating having excellent anti-icing / deicing performance under a low temperature and high relative humidity environment as claimed in claim 1, characterized in that: In step (4), the substrate includes aluminum alloy, magnesium alloy, glass, stainless steel, PP, and ABS.

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