A Fe 3 O 4 / SiO 2 Photothermal super-hydrophobic coating and preparation method and application thereof

Abstract

The present invention relates to the technical field of coating materials, and particularly relates to a Fe3O4 / SiO2 photothermal superhydrophobic coating, its preparation method and application. In the present invention, polydimethylsiloxane (PDMS) with low surface energy is used as an adhesive on the surface of an aluminum plate, and Fe3O4 and Fe3O4 / SiO2 dispersions are respectively sprayed to form a hydrophobic coating with a photothermal effect. Fe3O4 provides the photothermal effect and forms a certain micro-nano rough structure on the surface of the coating. At the same time, after adding SiO2 for modification, the hydrophobicity is further enhanced, and the contact angle can reach 155°, which can greatly delay the icing time and accelerate the melting of ice and frost. Under one sun illumination, the temperature rise reaches 71.8 °C. In addition, the coating has self-cleaning ability, can effectively avoid serious pollution, and exhibits certain anti-wind and sand impact ability and good mechanical stability, providing a new direction for the development of anti-icing materials.

Description

Technical Field

[0001] The present invention relates to the technical field of coating materials, and in particular to a Fe 3 O 4 / SiO 2 Photothermal super-hydrophobic coating and preparation method and application thereof. Background Art

[0002] Snow, fog and ice rain in winter not only bring huge challenges to the transportation system, but also have a profound impact on urban infrastructure, energy supply and environmental sustainability. Especially in cold areas, the accumulation of ice and snow and the freezing of precipitation pose a serious threat to road safety and traffic smoothness. With the continuous intensification of climate change, the frequency and intensity of winter ice accumulation events are gradually increasing, and effective anti-icing methods are needed to deal with the problem of winter ice accumulation. Traditional anti-icing methods, such as salt spreading, mechanical deicing and thermal deicing, are effective to a certain extent, but they also have a series of problems such as environmental pollution, high energy consumption and traffic congestion. Therefore, it is crucial to seek more efficient and environmentally friendly anti-icing methods.

[0003] In recent years, some new anti-icing methods have been discussed by many scholars. Among them, the most representative one is the use of photothermal super-hydrophobic surfaces for anti-icing. Its principle involves two key concepts: photothermal effect and super-hydrophobicity. Photothermal effect refers to the fact that when a material absorbs light energy, it will generate heat energy, causing the surface temperature to rise. This local temperature rise can quickly melt the ice and snow attached to the surface, thereby preventing it from accumulating. Super-hydrophobicity is a property of the surface, which is manifested as a high contact angle of water droplets on the surface, usually greater than 150°. This means that water droplets cannot adhere firmly to the surface, but roll in the form of beads, thereby slipping off the surface. Super-hydrophobic surfaces have a special structure at the micro-nano level, which prevents water molecules from interacting with their surface, thereby also achieving a certain self-cleaning and anti-fouling ability. In the past, some scholars only used surfaces with photothermal effects for anti-icing. Although it can accelerate the melting of ice, when the light is lost, due to insufficient surface hydrophobicity, it often leads to secondary icing. Combining photothermal surfaces with super-hydrophobicity not only reduces energy consumption, but also eliminates adverse effects on the environment. The World Meteorological Organization announced in 1981 that the radiation intensity of sunlight reaching the ground after being scattered and refracted by clouds is 1000W / m 2 , which is defined as one sun illumination. Jiang et al. prepared a super hydrophobic coating of silicon carbide / carbon nanotubes on the surface of EVA by spraying. The surface formed a micro-nano rough structure, and the contact angle of water droplets on the surface was as high as 161°. Under one sun illumination, the coating temperature rose rapidly, and the photothermal conversion efficiency was as high as 50%, with good photothermal effect. The World Meteorological Organization announced in 1981 that the radiation intensity of sunlight reaching the ground after being scattered and refracted by clouds is 1000W / m 2, which is defined as one sun illumination. Wu et al. used incompletely burned candle ash to construct a photothermal super hydrophobic surface. The incompletely burned particles formed a certain degree of micro-nano structure. At the same time, the black candle ash also has natural light absorption ability. Under one sun illumination intensity, the temperature rise can reach 53°C. Xie et al. used the template method to construct a super hydrophobic surface with a microarray structure, and then sprayed a layer of carbon powder on the surface, thereby increasing the photothermal effect. Under one sun illumination, the temperature rise can reach 85°C after five minutes. Li et al. used TiN nanoparticles with photothermal effect as the substrate, and then SiO 2 The particles are coated on the surface of the substrate, thus constructing a super-hydrophobic surface with photothermal effect. Under the illumination of one sun, the temperature rise can reach 45°C after 10 minutes. Many scholars mostly use carbon-based materials as photothermal agents. Although they have good photothermal response, they also have problems such as high cost and difficult preparation. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a Fe 3 O 4 / SiO 2 Photothermal super hydrophobic coating and preparation method and application thereof, the present invention selects polydimethylsiloxane as a binder, Fe 3 O 4 / SiO 2 The dispersion is sprayed on the PDMS surface to form a micro-nanoscale rough structure, which improves the anti-icing performance of the coating.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A Fe 3 O 4 / SiO 2 The preparation method of the photothermal super-hydrophobic coating comprises the following steps:

[0007] Spraying a polydimethylsiloxane solution on the surface of the substrate, using polydimethylsiloxane with low surface energy as an adhesive, and then pre-curing to form a bonding layer;

[0008] Spray Fe on the bonding layer surface 3 O 4 and SiO 2 Dispersion, solidification, Fe 3 O 4 Provide photothermal effect and form a certain micro-nano rough structure on the coating surface, while adding SiO 2 After modification, the hydrophobicity is further enhanced, and Fe 3 O 4 / SiO 2 Photothermal superhydrophobic coating.

[0009] In a preferred embodiment of the present invention, the polydimethylsiloxane solution is prepared by mixing a polydimethylsiloxane main agent, a polydimethylsiloxane curing agent and ethyl acetate.

[0010] In a preferred embodiment of the present invention, the usage ratio of the polydimethylsiloxane main agent, the polydimethylsiloxane curing agent and ethyl acetate is 10-12 g: 1 g: 50-55 mL, and the polydimethylsiloxane curing agent is a platinum catalyst.

[0011] In a preferred embodiment of the present invention, Fe 3 O 4 and SiO 2 In the dispersion, the dispersant is ethanol, Fe 3 O 4 、SiO 2 The dosage ratio of ethanol is 7-8g:1g:7-8mL.

[0012] In a preferred embodiment of the present invention, the pre-curing time is 8 to 10 minutes and the pre-curing temperature is 70 to 80°C.

[0013] In a preferred embodiment of the present invention, the curing temperature is 150-180° C. and the curing time is 2-3 hours.

[0014] In a preferred embodiment of the present invention, the spraying method is air spraying with a spray gun, which uses compressed air to generate an air flow to spray the material out of the nozzle.

[0015] In a preferred embodiment of the present invention, the substrate material is an aluminum alloy.

[0016] Another object of the present invention is to provide a Fe prepared by any of the above-mentioned preparation methods. 3 O 4 / SiO 2 Photothermal superhydrophobic coating.

[0017] The third object of the present invention is to provide a kind of Fe 3 O 4 / SiO 2 Application of photothermal superhydrophobic coating in anti-icing materials.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention uses low surface energy polydimethylsiloxane (PDMS) as an adhesive on the surface of the aluminum plate and sprays Fe 3 O 4 / SiO 2 dispersion, forming a hydrophobic coating with photothermal effect, Fe3 O 4 Provide photothermal effect and form a certain micro-nano rough structure on the coating surface, while adding SiO 2 After modification, the hydrophobicity is further enhanced, and the contact angle can reach 155°, which can greatly delay the freezing time and accelerate the melting of frost. Under the illumination of one sun, the temperature rise reaches 71.8°C. In addition, the coating has self-cleaning ability, can effectively avoid serious pollution, and shows a certain resistance to wind and sand impact and good mechanical stability, providing a new direction for the development of anti-icing materials.

[0020] 2. The photothermal super-hydrophobic coating prepared by the present invention has excellent anti-icing performance. Through comparative experiments, it can be seen that the coating can greatly delay the freezing time and also has an excellent photothermal effect. Under the illumination of one sun, the FPD coating containing frost completely defrosts into water within 290 seconds, and the FSPD coating is completely defrosted in only 156 seconds. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The coating preparation process of the present invention is as follows;

[0022] Figure 2 The SEM images of the FPD and FSPD of the present invention at different magnifications, a to c are FPD, d to f are FSPD;

[0023] Figure 3 The static contact angle diagram of the water drop on PDMS, FPD and FSPD of the present invention, a is PDMS, b is FPD, c is FSPD;

[0024] Figure 4 These are the imaging diagrams of PDMS, FPD and FSPD in water of the present invention, a is PDMS, b is FPD, and c is FSPD;

[0025] Figure 5 The process of water droplets on PDMS, FPD and FSPD of the present invention to complete freezing, (A) is PDMS, (B) is FPD, and (C) is FSPD;

[0026] Figure 6 The process of completely defrosting PDMS, FPD and FSPD into water according to the present invention, (A) is PDMS, (B) is FPD, and (C) is FSPD;

[0027] Figure 7 It is the temperature rise line graph of PDMS, FPD and FSPD of the present invention;

[0028] Figure 8 It is the temperature rise infrared imaging of PDMS, FPD and FSPD of the present invention;

[0029] Fig. 9 a~f are the FSPD self-cleaning process of the present invention;

[0030] Fig.10 The graph shows the changes of the contact angle and the rolling angle of the coating of the present invention with the impact of sand of different masses. DETAILED DESCRIPTION

[0031] The following is a detailed description of the technical solutions in the embodiments of the present invention in combination with the preferred embodiments and the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] It should be noted that all professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specifically stated, various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods.

[0033] Experimental reagents and instruments

[0034] Ferroferric oxide powder (45μm); polydimethylsiloxane main agent; polydimethylsiloxane curing agent; silicon dioxide powder (60nm); anhydrous ethanol (99%); ethyl acetate, analytical grade (99%); sandpaper (1000 mesh). Ultrasonic cleaning machine (3.2L 120W); spray gun (HD-1500.3mm); refrigeration table; infrared camera (E30); vacuum drying oven (DZF-6210AB); contact angle meter (GYJJ-12); simulated light lamp (100-300w); high-definition camera (R6); refrigeration box (-20℃~+20℃).

[0035] Example 1

[0036] A Fe 3 O 4 / SiO 2 The preparation method of the photothermal super-hydrophobic coating comprises the following steps:

[0037] (1) The aluminum plate was polished with sandpaper to remove the surface oxide layer, ultrasonically cleaned for 10 minutes to remove surface pollutants, then rinsed with anhydrous ethanol, and finally dried in a nitrogen stream;

[0038] (2) mixing the polydimethylsiloxane main agent and the polydimethylsiloxane curing agent platinum catalyst in a mass ratio of 10:1 and adding 50 mL of ethyl acetate and stirring evenly to form a polydimethylsiloxane (PDMS) solution;

[0039] (3) Use a 0.3 mm diameter spray gun at a 45° angle to the aluminum plate surface to evenly spray the PDMS solution on the aluminum plate surface, and place it in a vacuum drying oven at 80°C for pre-curing for 10 minutes;

[0040] (4) Fe 3 O 4 、SiO 2 and anhydrous ethanol in a ratio of 8 g:1 g:8 mL, dispersed by ultrasonic for 30 min, sprayed on a pre-cured aluminum plate, and then cured at 150 ° C for 2 hours to obtain Fe 3 O 4 / SiO 2 The photothermal superhydrophobic coating, denoted as FSPD, is prepared by the following process: Figure 1 shown.

[0041] Example 2

[0042] A Fe 3 O 4 / SiO 2 The preparation method of the photothermal super-hydrophobic coating comprises the following steps:

[0043] (1) The aluminum plate was polished with sandpaper to remove the surface oxide layer, ultrasonically cleaned for 10 minutes to remove surface pollutants, then rinsed with anhydrous ethanol, and finally dried in a nitrogen stream;

[0044] (2) mixing the polydimethylsiloxane main agent and the polydimethylsiloxane curing agent platinum catalyst in a mass ratio of 12:1 and adding 55 mL of ethyl acetate and stirring evenly to form a PDMS solution;

[0045] (3) Use a 0.3 mm diameter spray gun at a 45° angle to the aluminum plate surface to evenly spray the PDMS solution on the aluminum plate surface, and place it in a 70°C vacuum drying oven for pre-curing for 10 minutes;

[0046] (4) Fe 3 O 4 、SiO 2 and anhydrous ethanol in a ratio of 7g:1g:7mL, dispersed by ultrasonic for 30min, sprayed on a pre-cured aluminum plate, and then cured at 180℃ for 3h to obtain Fe 3 O 4 / SiO 2 Photothermal superhydrophobic coating.

[0047] Example 3

[0048] A Fe 3 O 4 / SiO 2The preparation method of the photothermal super-hydrophobic coating comprises the following steps:

[0049] (1) The aluminum plate was polished with sandpaper to remove the surface oxide layer, ultrasonically cleaned for 10 minutes to remove surface pollutants, then rinsed with anhydrous ethanol, and finally dried in a nitrogen stream;

[0050] (2) mixing the polydimethylsiloxane main agent and the polydimethylsiloxane curing agent in a mass ratio of 11:1 and adding 52 mL of ethyl acetate and stirring evenly to form a PDMS solution;

[0051] (3) Use a 0.3 mm diameter spray gun at a 45° angle to the aluminum plate surface to evenly spray the PDMS solution on the aluminum plate surface, and place it in a 75°C vacuum drying oven for pre-curing for 9 minutes;

[0052] (4) Fe 3 O 4 、SiO 2 and anhydrous ethanol in a ratio of 7.5 g: 1 g: 7.5 mL, dispersed by ultrasonic for 30 min, sprayed on a pre-cured aluminum plate, and then cured at 160 ° C for 2.5 hours to obtain Fe 3 O 4 / SiO 2 Photothermal superhydrophobic coating.

[0053] Comparative Example 1

[0054] (1) The aluminum plate was polished with sandpaper to remove the surface oxide layer, ultrasonically cleaned for 10 minutes to remove surface pollutants, then rinsed with anhydrous ethanol, and finally dried in a nitrogen stream;

[0055] (2) mixing the polydimethylsiloxane main agent and the polydimethylsiloxane curing agent platinum catalyst in a ratio of 10:1 and adding 50 mL of ethyl acetate and stirring evenly to form a PDMS solution;

[0056] (3) Use a 0.3 mm diameter spray gun at a 45° angle to the aluminum plate surface to evenly spray the PDMS solution on the aluminum plate surface and place it in a vacuum drying oven for pre-curing for 10 minutes;

[0057] (4) Fe 3 O 4 The mixture was stirred evenly with anhydrous ethanol in a ratio of 1:1, and dispersed evenly by ultrasonic for 30 min, and then sprayed on a pre-cured aluminum plate to obtain Fe 3 O 4 The mixed coating of PDMS was then cured at 150 °C for 2 h and was recorded as FPD.

[0058] Testing and Characterization

[0059] Surface morphology analysis: Characterize the microstructure and size of the surface through electron microscopy to gain insight and reveal the fine features of the coating surface.

[0060] Wetting performance test: Use an optical contact angle meter to measure the contact angle (CA) of a water drop on the surface, with a water volume of 3uL; then measure the sliding angle (SA), with a water volume of 6uL. During the measurement of SA and CA, five different positions need to be selected and their average values ​​taken to fully evaluate the wetting performance of the coating.

[0061] Anti-icing performance test: The anti-icing performance is tested by comparing the samples and observing the time it takes for the coating to delay the freezing of water droplets. Different samples are placed in a freezer, the temperature is set to -15℃, the relative humidity is set to about 30%, and a camera is used to record the time it takes for water droplets on different samples to completely change from liquid to solid.

[0062] Photothermal performance test: Place different samples on a refrigeration table at -10°C and set the relative humidity to 30% until a layer of frost forms. Then use a simulated light lamp 25 cm away from the sample at one sun illumination, and use a camera to record and observe the defrosting time. Build a foam insulation platform, place a simulated light lamp 25 cm away from the sample surface, and use an infrared camera to observe the surface temperature rise at one sun illumination.

[0063] Self-cleaning performance test: Sprinkle a certain amount of green chalk powder on the coated sample and place it at an angle of 30°. Use a syringe to inject 60 mL of deionized water vertically onto the coating surface. Observe the flow direction of water droplets and powder on the coating surface to verify the self-cleaning ability.

[0064] Coating stability test: Use a sandblasting gun to impact the coating surface with sand of different masses at a distance of 25 cm from the coating surface. After the impact, measure the contact angle and rolling angle again to observe the changes in the angles, thereby verifying the coating stability.

[0065] Results Analysis

[0066] FPD and FSPD surface microstructure characterization

[0067] like Figure 2 As shown in the figure, in the scanning electron microscope characterization of FPD and FSPD at different magnifications, their surface morphology and size characteristics are clearly shown.

[0068] observe Figure 2 In the morphology of Figure a and Figure d, the surface of FPD shows dense rough particles, which reduces the contact between water droplets and the coating surface and shows a certain degree of hydrophobicity. The FSPD has a finer particle feel, which can be attributed to the SiO 2The addition further increases the roughness of its surface, which helps to improve the hydrophobicity. In the morphology of Figures b and e, FSPD presents a deeper pit structure relative to FPD, and light can be refracted multiple times inside the pits, thereby optimizing the light storage effect. In the morphology of Figures c and f, the particles of FPD and FSPD are further magnified. It is obvious that particles of different sizes on the surface of FSPD are combined with each other, which is more dense, presenting a micro-nanoscale rough structure and better hydrophobicity. This detailed characterization result reveals the difference in surface properties of FSPD compared to FPD at different scales.

[0069] Wetting performance test

[0070] The contact angle measurement results are as follows Figure 3 As shown in a~c, it can be seen that the hydrophobicity of PDMS, FPD and FSPD increases in turn, among which FSPD shows excellent hydrophobic performance, and its contact angle (CA) can reach 155°. Compared with PDMS and FPD, water droplets are more like standing upright on the coating surface, and its rolling angle (SA) reaches 5°, and a slight tilt can make the water droplets roll off.

[0071] SEM morphology analysis shows that SiO 2 The introduction of significantly increased the roughness of the micro-nanostructure, thereby effectively improving the hydrophobicity of the coating. The three samples were placed in water for comparative observation. The images in water are shown in the following figure. Figure 4 As shown in a to c, it can be seen that there is no obvious change in PDMS, there are trace bubbles on the surface of FPD, and a silver mirror luster appears on the surface of FSPD. This is because the hydrophobic surface captures the air layer, causing a large number of bubbles to attach to the surface. The stronger the hydrophobicity, the stronger the ability to capture bubbles. When the surface reaches super-hydrophobicity, the bubbles in the coating will cover the surface in water, and due to the reflection effect of light, a silver mirror luster will appear. This also proves that FSPD has the strongest hydrophobicity, followed by PFD, and PDMS is the weakest.

[0072] Anti-ice performance

[0073] The FSPD, FPD and PDMS aluminum plates were placed in a freezer at -15°C and 30% relative humidity, and 30 μL of water was dripped into each of them. The freezing process was recorded with a camera. Complete freezing was judged by the formation of ice tips by water drops. Figure 5As shown, (A) is the PDMS coating, (B) is the FPD coating, and (C) is the FSPD coating. The PDMS coating has no obvious changes at 60s, and the bottom begins to freeze at 144s. The water droplets become no longer transparent at 196s, and the water droplets are completely frozen to form ice tips at 235s. The FPD coating suddenly begins to freeze at 273s, the water droplets begin to become turbid at 310s, and completely freeze at 401s. The complete freezing time is 166s later than that of the PDMS coating. The water droplets of the FSPD coating begin to freeze at 364s, the water droplets become turbid and opaque at 446s, and completely freeze at 530s to form ice tips. The complete freezing time of FSPD is 129s later than that of FPD and 295s later than that of PDMS. This result can be explained from the perspective of roughness and heat transfer coefficient. The PDMS coating is relatively flat, and the contact area between the droplet and the surface is large. The formation of ice begins with spontaneous heterogeneous nucleation generated at the solid-liquid interface and gradually grows from the bottom to the top. Since the surface of FPD coating is a rough micro-nano structure, there is a certain air gap in contact with the surface, and the heat transfer coefficient is lower than PDMS, which delays the freezing time. The roughness of FSPD coating is greater, so that the droplets form a tiny air cushion with the coating surface, and the heat transfer coefficient becomes smaller, so the freezing is delayed most significantly.

[0074] Light and thermal performance

[0075] (1) Photothermal defrosting

[0076] PDMS, FPD and FSPD were placed on a -10°C refrigeration table for 30 minutes to frost them. The light simulation lamp was turned on and the PDMS, FPD and FSPD were placed on a -10°C refrigeration table for 30 minutes to frost them. 2 ) to observe the frost on the coating surface and record the process. Figure 6 As shown. Figure (A) shows the PDMS coating. At 320s, the frost layer on the coating surface showed signs of slight melting, and at 417s, it completely melted into water. Figure (B) shows the FPD coating. At 240s, the ice crystals on the surface showed signs of slight melting, and at 290s, it completely melted into water. Figure (C) shows the FSPD coating. At 128s, the frost layer on the surface melted slightly, and after 156s, it completely melted into water.

[0077] (2) Photothermal temperature rise

[0078] Under the condition that the room temperature is maintained at about 23℃, we placed PDMS, FPD and FSPD on the self-built insulation foam, turned on the light simulation lamp, the light intensity is one sun illumination, and used an infrared camera to observe the temperature rise of the surface. The results are as follows Figure 7 , Figure 8As shown in the figure. After 10 minutes of light exposure, the surface temperature of the PDMS coating can only reach 31°C, and it tends to be stable and no longer changes. However, the surfaces of FPD and FSPD both contain ferroferric oxide particles with photothermal effect. The FPD reaches 64°C after ten minutes, and the FSPD coating rises to a maximum temperature of 71.8°C at the same time, and finally tends to be stable.

[0079] The difference in temperature rise between FPD and FSPD is due to SiO 2 The introduction of SiO 2 It has a certain ability to capture light and triggers the interface effect of the coating, increasing its surface roughness and more pit structures. According to the principle of light trapping, the light is reflected and refracted multiple times in the pits, which enhances the absorption and storage of light energy. Therefore, the temperature rise effect is improved. This result not only highlights the excellent performance of the coating in the photothermal effect, but also provides a valuable reference for the design and development of new high-efficiency photothermal materials.

[0080] Self-cleaning performance

[0081] In real life, coatings are often inevitably covered by dust or pollutants, so their self-cleaning ability is particularly important. In order to test the self-cleaning effect of the photothermal superhydrophobic coating, homemade green chalk powder was used instead of dust for the experiment. Fig. 9 As shown in Figures af, the powder is evenly spread on the coating surface and tilted at 30°. Then a 60mL syringe is used to inject water vertically to the horizontal plane on the coating surface. The injection is completed after one minute. As can be seen in Figure c, the powder will roll down the surface with the water droplets. When all the surface powder rolls off, the surface remains dry. This phenomenon is due to the low adhesion of water droplets on the superhydrophobic coating, which allows the water droplets to easily roll down and carry away surface pollutants. This clearly shows that the FSPD coating has excellent self-cleaning properties. The self-cleaning property not only improves the aesthetics of the coating, but also enhances its durability under various environmental conditions, providing a reliable basis for its widespread use in practical applications.

[0082] Mechanical stability

[0083] Considering that the coating will inevitably be impacted by wind and sand during actual application, the mechanical stability of the coating plays an important role in the durability of the coating. The mechanical stability of the coating is evaluated by using a sandblasting gun to impact sand of different masses at a distance of 25 cm from the coating and measuring the change in contact angle after the impact.

[0084] Mechanical stability

[0085] Fig.10The curves of the contact angle and rolling angle of water droplets on the coating surface with the impact of different sand masses are shown. It can be seen from the graph that as the sand mass gradually increases, the contact angle and rolling angle of the coating change slightly, but still maintain the superhydrophobic properties. This shows that the FSPD coating has excellent mechanical stability.

[0086] in conclusion

[0087] (1) A super-hydrophobic surface with photothermal effect was prepared by spraying Fe 3 O 4 The particles make the surface hydrophobic. On this basis, silica modification is added, and the contact angle is as high as 155°. It can be seen from the characterization that Fe 3 O 4 The coating surface will show a certain degree of roughness. 2 The addition of will make the surface particles finer, the pit structure more, and the roughness improved, thereby increasing the hydrophobicity and enhancing the photothermal effect.

[0088] (2) The prepared photothermal superhydrophobic coating has excellent anti-icing performance. Through comparative experiments, it can be seen that the coating can greatly delay the freezing time and also has an excellent photothermal effect. Under the illumination of one sun, the FPD coating containing frost completely defrosts into water within 290 seconds, and the FSPD coating completely defrosts in only 156 seconds. At the same time, the FPD coating can reach 64°C and the FSPD can reach 71.8°C.

[0089] (3) The photothermal super-hydrophobic coating has a certain self-cleaning ability. Due to the low adhesion of water droplets, they can take away the dust on the surface when rolling down the surface, keeping the surface clean and dry. In addition, the coating has a certain mechanical stability. When impacted by wind and sand of different masses, the contact angle of the coating changes slightly, and it still maintains the super-hydrophobic property, laying a good foundation for practical applications.

[0090] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes a preferred embodiment. Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the attached claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0091] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a Fe3O4 / SiO2 photothermal super-hydrophobic coating, characterized in that: The following steps are involved: Spraying a polydimethylsiloxane solution of adhesive on the surface of the substrate, followed by pre-curing to form a bonding layer; Spray Fe3O4 and SiO2 dispersion on the surface of the bonding layer and solidify it to obtain a Fe3O4 / SiO2 photothermal super hydrophobic coating; In the Fe3O4 and SiO2 dispersion, the dispersant is ethanol, and the dosage ratio of Fe3O4, SiO2 and ethanol is 7-8g:1g:7-8mL.

2. The preparation method of Fe3O4 / SiO2 photothermal super hydrophobic coating according to claim 1, characterized in that, The polydimethylsiloxane solution is prepared by mixing a polydimethylsiloxane main agent, a polydimethylsiloxane curing agent and ethyl acetate, wherein the usage ratio of the polydimethylsiloxane main agent, the polydimethylsiloxane curing agent and the ethyl acetate is 10-12g:1g:50-55mL.

3. The preparation method of Fe3O4 / SiO2 photothermal super hydrophobic coating according to claim 2, characterized in that, The polydimethylsiloxane curing agent is a platinum catalyst.

4. The preparation method of Fe3O4 / SiO2 photothermal super hydrophobic coating according to claim 1, characterized in that, The pre-curing time is 8 to 10 minutes, and the pre-curing temperature is 70 to 80°C.

5. The preparation method of Fe3O4 / SiO2 photothermal super hydrophobic coating according to claim 1, characterized in that, The curing temperature is 150-180°C and the curing time is 2-3 hours.

6. The preparation method of Fe3O4 / SiO2 photothermal super hydrophobic coating according to claim 1, characterized in that, The spraying method is air spray with a spray gun.

7. The preparation method of the Fe3O4 / SiO2 photothermal super hydrophobic coating according to claim 1, characterized in that, The base material is aluminum alloy.

8. A Fe3O4 / SiO2 photothermal super hydrophobic coating prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the Fe3O4 / SiO2 photothermal super-hydrophobic coating according to claim 8 in anti-deicing materials.

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