Super-hydrophobic coating based on mineralization process and spraying process optimization as well as preparation method and application of super-hydrophobic coating

Abstract

The invention provides a super-hydrophobic coating based on mineralization process and spraying process optimization and a preparation method and application thereof, and belongs to the technical field of building materials and functional coatings. The preparation method of the super-hydrophobic coating comprises the following steps: (1) adding carbide slag and fly ash into deionized water, stirring, introducing CO2, and carrying out mineralization treatment; after the mineralization treatment is completed, filtering and drying to obtain mineralized fly ash particles; (2) adding the mineralized fly ash particles and perfluorodecyltriethoxysilane into ethanol, uniformly stirring, and performing ultrasonic treatment to obtain a mixed solution; and spraying the obtained mixed solution onto a base material, and drying to obtain the super-hydrophobic coating. By optimizing mineralization parameters, the surface roughness of the coating is enhanced, meanwhile, the spraying process is optimized, and the contact angle of the super-hydrophobic coating can be remarkably increased.

Description

Technical Field

[0001] This invention belongs to the field of building materials and functional coating technology, specifically relating to a superhydrophobic coating based on optimized mineralization and spraying processes, its preparation method, and its application. Background Technology

[0002] Concrete, as the most commonly used structural material, is widely used in various infrastructures. However, concrete is exposed to the external environment for extended periods, making it susceptible to the penetration of moisture and corrosive ions. This can lead to problems such as steel corrosion, sulfate corrosion, and freeze-thaw damage, severely impacting durability and service life. Against this backdrop, superhydrophobic coatings, due to their excellent waterproofing properties, have become an effective means of improving concrete durability. A superhydrophobic surface is defined as a surface where the contact angle of a water droplet is greater than 150° and the roll-off angle is less than 10°. The superhydrophobic properties of lotus leaves in nature have sparked research interest in biomimetic coatings. On one hand, lotus leaves possess a waxy layer with low surface energy; on the other hand, they exhibit highly complex micro- and nano-structures. Constructing such a coating forms a protective layer on the surface of concrete structures, preventing moisture ingress and blocking the invasion of harmful ions; effectively reducing the damage to concrete caused by freeze-thaw cycles and chloride ion corrosion, thus improving concrete durability.

[0003] Fly ash is a large amount of industrial solid waste emitted by coal-fired power plants. It has low activity and is mostly spherical. Calcium carbide slag is a highly alkaline waste residue produced during the production of acetylene. It contains abundant active CaO and has a high CO2 mineralization capacity.

[0004] To prepare a surface similar to that of a lotus leaf, suitable micro- and nano-structures and low surface energy materials are required. Therefore, it is of great significance to prepare a superhydrophobic coating of fly ash by optimizing the mineralization and spraying processes using fly ash and carbide slag as raw materials. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a superhydrophobic coating based on optimized mineralization and spraying processes, along with its preparation method and applications. By optimizing mineralization parameters to enhance coating surface roughness and simultaneously optimizing the spraying process, this invention significantly improves the contact angle of the coating, thereby obtaining a superhydrophobic coating.

[0006] The technical solution of the present invention is as follows: A method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes includes the following steps: (1) Add carbide slag and fly ash to deionized water, stir, and then introduce CO2 for mineralization treatment; after mineralization treatment, filter and dry to obtain mineralized fly ash particles. (2) Add mineralized fly ash particles and perfluorodecyltriethoxysilane to ethanol, stir evenly, and then perform ultrasonic treatment to obtain a mixture; spray the obtained mixture onto the substrate and dry it to obtain a superhydrophobic coating.

[0007] According to a preferred embodiment of the present invention, the carbide slag in step (1) comprises the following components in parts by mass: 88-90 parts CaO, 2-4 parts SiO2, 3-4 parts SO3, 1-1.5 parts Al2O3, and 0.2-0.5 parts MgO; the particle size of the carbide slag is 2-10 μm, more preferably 4 μm.

[0008] According to a preferred embodiment of the present invention, the fly ash in step (1) comprises the following components in parts by mass: 52-56 parts SiO2, 34-36 parts Al2O3, 4-5 parts Fe2O3, 2-3 parts CaO, and 0.5-1 parts MgO; the particle size of the fly ash is 1-8 μm, more preferably 6 μm, and the specific surface area of ​​the fly ash is 550-650 m². 2 / g.

[0009] According to a preferred embodiment of the present invention, the mass of the carbide slag in step (1) is 5-15% of the total mass of the carbide slag and fly ash; controlling the mass of the carbide slag within the above range can prevent the calcium carbonate coating of the fly ash from being too sparse or too dense, thus reducing the roughness.

[0010] According to a preferred embodiment of the present invention, the volume ratio of the deionized water in step (1) to the total mass of carbide slag and fly ash is 6-10 mL:1 g, and more preferably 8 mL:1 g.

[0011] According to a preferred embodiment of the present invention, the stirring temperature in step (1) is 0-80°C, more preferably 20°C, the stirring is performed until the pH of the system remains constant, and the stirring speed is 300-800 rpm.

[0012] According to a preferred embodiment of the present invention, the flow rate of CO2 in step (1) is 1-2 L / min; controlling the flow rate of CO2 can effectively control the crystal nucleus size and distribution.

[0013] According to the present invention, the temperature of the mineralization treatment in step (1) is 0-80℃, more preferably 20℃; when CO2 is introduced and the reaction is carried out until the pH of the system reaches 6-9, the mineralization treatment is stopped; the stirring speed in the mineralization treatment is 300-800 rpm; the specific mineralization treatment temperature of the present invention can suppress the excessive formation of calcite.

[0014] According to a preferred embodiment of the present invention, the drying in step (1) is performed at 100-110°C for 10-15 hours.

[0015] According to a preferred embodiment of the present invention, the mass ratio of the mineralized fly ash particles to the volume of ethanol in step (2) is 1-2 g: 10 mL.

[0016] According to a preferred embodiment of the present invention, the mass ratio of perfluorodecyltriethoxysilane (CAS No.: 101947-16-4) to mineralized fly ash particles in step (2) is 1:25-50.

[0017] According to a preferred embodiment of the present invention, the stirring speed in step (2) is 2000-4000 rpm, and the stirring time is 0.5-1.5 h.

[0018] According to a preferred embodiment of the present invention, the ultrasonic power in step (2) is 500-2000W, the ultrasonic temperature is 20-30℃, and the pressure is 0.15-0.4MPa; the ultrasonication is carried out in an ultrasonic reactor for 0.5-1.5h.

[0019] According to a preferred embodiment of the present invention, the spraying conditions in step (2) are: nozzle diameter of 0.3-1 mm, pressure of 0.3-0.8 MPa, and spraying distance of 15-30 cm.

[0020] According to a preferred embodiment of the present invention, the spraying in step (2) is carried out in multiple sprayings, and each spraying is dried at room temperature for 10-20 minutes before the next spraying is carried out, with the thickness of each spraying being 0.5-1.5 mm.

[0021] According to a preferred embodiment of the present invention, before the substrate described in step (2) is sprayed with the adhesive fluorinated styrene-acrylic emulsion, the specific spraying method is as follows: the fluorinated styrene-acrylic emulsion is added to deionized water to obtain the adhesive spraying solution, the mass ratio of the fluorinated styrene-acrylic emulsion to deionized water is 8-12:1; the adhesive spraying solution is sprayed onto the surface of the substrate after dust removal treatment, and dried at room temperature for 5-10 minutes. The spraying conditions of the adhesive spraying solution are: nozzle diameter is 0.7 mm, air pressure is 0.3-0.6 MPa, spraying distance is 15-30 cm, and thickness is 1-3 mm; the fluorinated styrene-acrylic emulsion has good film-forming properties, flexibility and weather resistance, and the fluorinated functional groups give it excellent hydrophobic properties, which is suitable for constructing adhesives. The adhesive solution is uniformly sprayed onto the surface of the substrate to form a thin film, which initially seals the pores of the substrate and improves the adhesion.

[0022] More preferably, the fluorinated styrene-acrylic emulsion is prepared by the following method: perfluorodecyltriethoxysilane (CAS No.: 101947-16-4) is added to the styrene-acrylic emulsion and stirred evenly to obtain the emulsion. The mass ratio of perfluorodecyltriethoxysilane to styrene-acrylic emulsion is 2-5:100. The styrene-acrylic emulsion can be a commercially available product.

[0023] According to a preferred embodiment of the present invention, the drying in step (2) is performed at room temperature for 20-30 hours.

[0024] According to a preferred embodiment of the present invention, the substrate in step (2) is a mortar or concrete substrate that has undergone dust removal treatment.

[0025] According to a preferred embodiment of the present invention, the thickness of the superhydrophobic coating in step (2) is 1-10 mm.

[0026] The present invention also provides a superhydrophobic coating, which is prepared by the above preparation method.

[0027] According to the present invention, the above-mentioned superhydrophobic coating is used in the preparation of superhydrophobic mortar or concrete.

[0028] The technical features and beneficial effects of this invention are as follows: 1. This invention utilizes a wet mineralization process, mixing fly ash, carbide slag, and deionized water, and then introducing carbon dioxide to initiate a reaction. The carbide slag and fly ash undergo synergistic mineralization, allowing calcium carbonate to disperse and adhere ectopically to the fly ash surface. This structure differs from the structure of carbonation products from single carbide slag, thus contributing to improved carbon fixation rate and product performance, as well as better product stability. Different mineralization parameters result in variations in the surface morphology and roughness of the mineralized product. Roughness and surface morphology are intrinsically related to the contact angle; therefore, in practical applications, this invention can adjust the Ra roughness of the fly ash surface after mineralization by controlling the mineralization reaction parameters, thereby achieving higher superhydrophobic properties.

[0029] 2. This invention uses fly ash, an industrial waste, as the main raw material, realizing the resource utilization of waste and reducing environmental pollution. Compared with traditional superhydrophobic coating preparation methods, the raw material cost is significantly reduced, resulting in good economic and environmental benefits.

[0030] 3. In this invention, the surface of the mineralized fly ash is covered with calcium carbonate particles, forming numerous protrusions that significantly increase surface roughness. According to Cassie theory, this rough structure reduces the actual contact area between the liquid and the solid, forming an air layer between the droplet and the solid surface, promoting droplet rolling and laying the foundation for superhydrophobic properties. Fluorosilanes have extremely low surface energy and hydrolyze to form silanols upon contact with mineralized fly ash. Silanols undergo a dehydration condensation reaction with the hydroxyl groups on the surface of fly ash and calcium carbonate particles, grafting fluoroalkyl groups onto their surfaces, significantly reducing surface energy, increasing the droplet contact angle, and further enhancing superhydrophobic properties. After spraying with a spray gun, the contact angle of the superhydrophobic coating is controlled by adjusting the thickness.

[0031] 4. This invention abandons the complex equipment and stringent processes required in traditional superhydrophobic coating preparation, employing a simple and easy-to-implement preparation process to complete the preparation of a superhydrophobic coating from fly ash mineralization. Precise control of reaction parameters is key to this invention. Temperature significantly affects the size of calcium carbonate crystals; increasing temperature increases the crystal size, but also reduces the stability of calcium carbonate, promoting a transformation towards a more stable morphology. Increasing the carbon dioxide flow rate reduces particle size. Lower pH results in a more complete reaction, but excessively low pH leads to the formation of calcium bicarbonate, which is detrimental to roughness construction. Therefore, this invention controls the pH between 6 and 9. By precisely controlling these parameters, efficient and stable reaction is ensured, production costs and technical barriers are reduced, creating conditions for large-scale industrial production. Overall, this invention, through two key steps—mineralization and surface modification—successfully constructs a superhydrophobic coating structure using simple processes and conventional equipment, greatly improving the feasibility of industrial production.

[0032] 5. This invention, by controlling the liquid-to-solid ratio, mineralization temperature, termination pH value, and coating thickness, produces a superhydrophobic coating with excellent performance. Its superhydrophobic angle is greater than 150°, effectively blocking the penetration of moisture and harmful ions, significantly improving the concrete's resistance to freezing, impermeability, and chemical erosion. Furthermore, the coating exhibits good durability, maintaining stable superhydrophobic properties even after long-term use, providing long-term protection for concrete structures and significantly extending their service life. It has enormous application potential in the field of building protection. Attached Figure Description

[0033] Figure 1 The particle size distribution diagrams are shown for mineralized fly ash particles and unmineralized fly ash particles obtained from mineralization with different liquid-solid ratios in Examples 1 and 4-5.

[0034] Figure 2 This is a SEM image of the mineralized fly ash particles obtained in Example 1.

[0035] Figure 3 This is a SEM image of the mineralized fly ash particles obtained in Example 2.

[0036] Figure 4 The image shown is the AFM image of the superhydrophobic coating obtained in Example 1.

[0037] Figure 5 The image shown is the AFM image of the superhydrophobic coating obtained in Example 2. Detailed Implementation

[0038] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with specific embodiments, but this is not the only description. Anything not described in detail in the present invention is based on conventional technology in the field.

[0039] The fly ash used in the examples comprises the following components in parts by weight: 55 parts SiO2, 35 parts Al2O3, 4 parts Fe2O3, 2 parts CaO, and 0.5 parts MgO; with a particle size of 6 μm and a specific surface area of ​​600 m². 2 / g; The carbide slag comprises the following components in parts by mass: 90 parts CaO, 2 parts SiO2, 3 parts SO3, 1.5 parts Al2O3, and 0.3 parts MgO, with a particle size of 4 μm.

[0040] Perfluorodecyltriethoxysilane: Industrial grade, purity ≥98%.

[0041] In this embodiment, the spraying equipment used is an industrial-grade air pump spray paint pen, a common commercially available product.

[0042] The fluorinated acrylic emulsions used in the examples and comparative examples were prepared according to the following method: Perfluorodecyltriethoxysilane was added to a styrene-acrylic emulsion and stirred until homogeneous to obtain the emulsion. The mass ratio of perfluorodecyltriethoxysilane to styrene-acrylic emulsion was 2:100. The styrene-acrylic emulsion had a solid content of 48%, a pH of 7.0±0.5, a viscosity of 200~500 mPa·s (25℃), and was a milky white, homogeneous emulsion with a density of approximately 1.01 g / cm³. It was purchased from BASF.

[0043] Atomic force microscope (AFM): Features a tapping mode and a scanning range of 0.1 μm-100 μm, used for measuring surface roughness.

[0044] The contact angle test was conducted using a contact angle measuring instrument. The test method was as follows: First, the superhydrophobic coating sample was placed on a stable platform. The instrument was turned on and all parameters were calibrated. 5 μL of deionized water was drawn up using a microsyringe to slowly generate a droplet on the sample surface. After the droplet stabilized, the instrument's image acquisition system captured the image, and the built-in software analyzed the contact point between the droplet profile and the sample surface to calculate the hydrophobic angle.

[0045] Example 1 A method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes includes the following steps: (1) Add 4g of carbide slag, 36g of fly ash and 320mL of deionized water to a three-necked flask. Place the flask in a water bath and turn on a magnetic stirrer. Stir at 600rpm for 1h at 20℃. After the pH value of the system remains unchanged, introduce CO2 at a flow rate of 2L / min. Mineralize the suspension at 600rpm and 20℃ until the pH of the suspension stabilizes at 7. Stop introducing CO2. After the mineralization treatment is completed, filter the solid obtained by filtration. Dry the solid obtained by filtration at 105℃ for 12h to obtain mineralized fly ash particles.

[0046] (2) Fluorine-modified acrylic emulsion and deionized water are mixed in a mass ratio of 10:1 to prepare a stable and uniform adhesive spraying liquid. The adhesive spraying liquid is uniformly sprayed onto the surface of the dust-removed concrete substrate using an air pressure spraying method with a nozzle diameter of 0.7 mm, an air pressure of 0.5 MPa, and a spraying distance of 20 cm to form a thin film. The film is dried at room temperature for 10 min to obtain concrete coated with adhesive with an adhesive thickness of 2 mm.

[0047] The mineralized fly ash particles and perfluorodecyltriethoxysilane obtained in step (1) were added to ethanol. The mass ratio of the mineralized fly ash particles to the volume of ethanol was 1g:10mL, and the mass ratio of perfluorodecyltriethoxysilane to the mineralized fly ash particles was 1:30. The mixture was then stirred at 3000rpm for 1h. The resulting mixture was then placed in an ultrasonic reactor for ultrasonic treatment for 1h. The ultrasonic power was 1000W, the ultrasonic temperature was 25℃, and the pressure was 0.3MPa to obtain a mixture. The mixture was then sprayed onto the concrete surface coated with adhesive. The spraying conditions were: nozzle diameter 0.7mm, air pressure 0.5MPa, spraying distance 20cm, spraying times 2, thickness of each spray 1mm, drying at room temperature for 15min after each spray, and natural drying at room temperature for 24 hours after spraying to obtain a superhydrophobic coating with a thickness of 2mm.

[0048] The particle size distribution diagram of the mineralized fly ash particles obtained in this embodiment is as follows: Figure 1 As shown, by Figure 1 It is evident that, compared to unmineralized fly ash particles, mineralization treatment can significantly optimize the particle size structure of fly ash particles, making their distribution more concentrated, which is beneficial for their uniform dispersion in the coating and improves coating performance. Furthermore, a high liquid-to-solid ratio leads to reaction dilution and insufficient mineralization, meaning some particles may not be effectively coated, resulting in slightly smaller particle sizes; conversely, a low liquid-to-solid ratio results in a more viscous reaction system, leading to overly dense coating but smaller crystal sizes, resulting in smaller particle sizes.

[0049] The SEM image of the mineralized fly ash particles obtained in this embodiment is as follows: Figure 2 As shown, by Figure 2 It can be seen that the surface of fly ash spherical particles is covered with a large number of regularly distributed, clearly shaped calcium carbonate crystals with a particle size of about several hundred nanometers to several micrometers and a moderate distribution density.

[0050] The AFM image of the superhydrophobic coating surface obtained in this embodiment is as follows. Figure 4 As shown, by Figure 4 It can be seen that the surface of the superhydrophobic coating has obvious micro-nano scale undulation structure and high surface roughness, which provides a good structural basis for the formation of superhydrophobic properties.

[0051] The surface roughness Ra of the superhydrophobic coating obtained in this embodiment is 14.689 μm, and the contact angle is 160.2°.

[0052] Example 2 A method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes is described in Example 1, except that the temperature of stirring and mineralization in step (1) is 40°C.

[0053] The SEM image of the mineralized fly ash particles obtained in this embodiment is as follows: Figure 3 As shown, by Figure 3 It can be seen that as the mineralization temperature increases, the surface of fly ash particles gradually undergoes structural changes, and the size of calcium carbonate crystals increases.

[0054] The AFM of the superhydrophobic coating obtained in this embodiment is as follows: Figure 5 As shown, the image exhibits obvious three-dimensional protrusions and depressions, with typical micro-nano structure undulations. This is the rough skeleton foundation necessary for constructing superhydrophobic properties. Moreover, the rough structure is relatively complex and uniformly distributed, which is conducive to the formation of air pockets to support water droplets.

[0055] The surface roughness Ra of the superhydrophobic coating obtained in this embodiment is 11.231 μm, and the contact angle reaches 155.6°.

[0056] Example 3 A method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes is described in Example 1, except that the temperature of stirring and mineralization in step (1) is 80°C.

[0057] The surface roughness Ra of the superhydrophobic coating obtained in this embodiment is 10.985 μm, and the contact angle reaches 152.6°.

[0058] Example 4 A method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes is described in Example 1, except that the volume of deionized water in step (1) is 400 mL and the liquid-to-solid ratio is 10:1.

[0059] The surface roughness Ra of the superhydrophobic coating obtained in this embodiment is 11.368 μm, and the contact angle reaches 153.9°.

[0060] Example 5 A method for preparing a superhydrophobic coating based on mineralization and spraying processes is described in Example 1, except that the volume of deionized water in step (1) is 200 mL and the liquid-to-solid ratio is 6:1.

[0061] The surface roughness Ra of the superhydrophobic coating obtained in this embodiment is 11.019 μm, and the contact angle reaches 152.9°.

[0062] Example 6 A method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes is described in Example 1, except that the pH value for terminating mineralization in step (1) is 9.

[0063] The surface roughness Ra of the superhydrophobic coating obtained in this embodiment is 9.854 μm, and the contact angle reaches 148.2°.

[0064] Example 7 A method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes is described in Example 1, except that the pH value for terminating mineralization in step (1) is 6.

[0065] The surface roughness Ra of the superhydrophobic coating obtained in this embodiment is 10.895 μm, and the contact angle reaches 153.2°.

[0066] Comparative Example 1 A method for preparing a superhydrophobic coating is described in Example 1, except that: in step (2), unmineralized fly ash is used directly, and step (1) is not performed.

[0067] The surface roughness of the superhydrophobic coating obtained in this comparative example is Ra=7.628μm, and the contact angle is 126.3°.

[0068] Compared with Comparative Example 1, the surface roughness of Example 1 was improved by 93% and the contact angle was improved by 27%.

[0069] Comparative Example 2 A method for preparing a superhydrophobic coating based on the optimization of mineralization and spraying processes is described in Example 1. The difference is that in step (2), a single spraying method is used to uniformly spray the mineralized slurry onto a clean concrete substrate using an air pressure spray gun, and the spraying thickness is controlled to be 2 mm. The remaining operations are kept the same.

[0070] The contact angle of the superhydrophobic coating obtained in this comparative example is 145.7°.

[0071] As can be seen from the above, the superhydrophobic coating provided by the present invention can alleviate the problem of concrete damage caused by water penetration, and the materials used are more environmentally friendly.

Claims

1. A method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes, characterized in that, The steps include the following: (1) Add carbide slag and fly ash to deionized water, stir, and then introduce CO2 for mineralization treatment; after mineralization treatment, filter and dry to obtain mineralized fly ash particles. (2) Add mineralized fly ash particles and perfluorodecyltriethoxysilane to ethanol, stir evenly, and then perform ultrasonic treatment to obtain a mixture; spray the obtained mixture onto the substrate and dry it to obtain a superhydrophobic coating.

2. The method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes according to claim 1, characterized in that, The carbide slag mentioned in step (1) comprises the following components in parts by mass: CaO 88-90 parts, SiO2 2-4 parts, SO3 3-4 parts, Al2O3 1-1.5 parts, MgO 0.2-0.5 parts; the particle size of the carbide slag is 2-10 μm, preferably 4 μm; The fly ash comprises the following components in parts by weight: SiO2 52-56 parts, Al2O3 34-36 parts, Fe2O3 4-5 parts, CaO 2-3 parts, and MgO 0.5-1 parts; the particle size of the fly ash is 1-8 μm, preferably 6 μm, and the specific surface area of ​​the fly ash is 550-650 m². 2 / g.

3. The method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes according to claim 1, characterized in that, The mass of the carbide slag in step (1) is 5-15% of the total mass of carbide slag and fly ash; the volume ratio of the deionized water to the total mass of carbide slag and fly ash is 6-10 mL:1 g, preferably 8 mL:1 g.

4. The method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes according to claim 1, characterized in that, The stirring temperature in step (1) is 0-80℃, preferably 20℃, and the stirring is carried out until the pH of the system remains constant. The stirring speed during the stirring process is 300-800 rpm. The CO2 flow rate is 1-2 L / min; the mineralization temperature is 0-80℃, preferably 20℃; the mineralization process is stopped when the pH of the system reaches 6-9 after the CO2 reaction is introduced; the stirring speed during the mineralization process is 300-800 rpm; the drying is carried out at 100-110℃ for 10-15 h.

5. The method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes according to claim 1, characterized in that, In step (2), the mass ratio of the mineralized fly ash particles to the volume of ethanol is 1-2 g: 10 mL; the mass ratio of the perfluorodecyltriethoxysilane to the mineralized fly ash particles is 1:25-50. The stirring speed in step (2) is 2000-4000 rpm, and the stirring time is 0.5-1.5 h; the ultrasonic power is 500-2000 W, the ultrasonic temperature is 20-30℃, and the pressure is 0.15-0.4 MPa; the ultrasonication is carried out in an ultrasonic reactor for 0.5-1.5 h.

6. The method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes according to claim 1, characterized in that, The conditions for spraying in step (2) are: nozzle diameter of 0.3-1mm, pressure of 0.3-0.8MPa, and spraying distance of 15-30cm; the spraying is carried out in multiple sprayings, and each spraying is dried at room temperature for 10-20 minutes before the next spraying, and the thickness of each spraying is 0.5-1.5mm.

7. The method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes according to claim 1, characterized in that, Before spraying the mixture in step (2), the substrate is first coated with a layer of fluorinated styrene-acrylic emulsion as an adhesive. The specific spraying method is as follows: add the fluorinated styrene-acrylic emulsion to deionized water to obtain the adhesive spraying solution. The mass ratio of the fluorinated styrene-acrylic emulsion to deionized water is 8-12:

1. Spray the adhesive spraying solution onto the surface of the substrate after dust removal treatment and dry it at room temperature for 5-10 minutes. The spraying conditions of the adhesive spraying solution are: nozzle diameter of 0.7 mm, air pressure of 0.3-0.6 MPa, spraying distance of 15-30 cm, and thickness of 1-3 mm. Preferably, the fluorinated styrene-acrylic emulsion is prepared by the following method: adding perfluorodecyltriethoxysilane to the styrene-acrylic emulsion and stirring until homogeneous, thereby obtaining the emulsion. The mass ratio of perfluorodecyltriethoxysilane to the styrene-acrylic emulsion is 2-5:

100.

8. The method for preparing a superhydrophobic coating based on optimized mineralization and spraying processes according to claim 1, characterized in that, The drying in step (2) is drying at room temperature for 20-30 hours; the substrate is a mortar or concrete substrate that has been dust-removed; the thickness of the superhydrophobic coating is 1-10 mm.

9. A superhydrophobic coating, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.

10. The application of the superhydrophobic coating of claim 9 in the preparation of superhydrophobic mortar or concrete.

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