Self-repairing super-hydrophobic coating based on magnetic hollow glass beads and preparation method of self-repairing super-hydrophobic coating

Abstract

The invention relates to the technical field of super-hydrophobic materials, and discloses a self-repairing super-hydrophobic coating based on magnetic hollow glass beads and a preparation method of the self-repairing super-hydrophobic coating. The coating is composed of a magnetic hollow glass bead roughness layer, a concave structure layer and a nano-particle hydrophobic layer. According to the method, magnetic hollow glass beads recovered and purified from fly ash of a thermal power plant are utilized, and directional enrichment and self-assembly of the magnetic hollow glass beads on the surface of a resin matrix are realized under the action of an external magnetic field; then, an inwards-concave structure with micro-nano composite characteristics is formed through hydrochloric acid etching, and hydrophobically-modified nano-particles are embedded into the surface of the inwards-concave structure, so that the super-hydrophobic interface with the self-repairing function is constructed. Obtaining a coating contact angle gt; the rolling angle is 160 degrees and the rolling angle is tilt; meanwhile, excellent hydrophobicity, corrosion resistance and self-repairing performance are achieved. The method is wide in raw material source, simple and convenient in process and low in cost, is suitable for preparing waterproof, antifouling and anti-corrosion coatings on the surfaces of metal, ceramic and other composite materials, and has a good industrial application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of super-hydrophobic materials, in particular to a self-repairing super-hydrophobic coating based on magnetic hollow glass beads and a preparation method thereof. BACKGROUND

[0002] Super-hydrophobic surfaces have excellent water-repellent, stain-repellent, and ice-repellent properties due to their special micro-nano structure and low surface energy, and are widely used in self-cleaning materials, corrosion-resistant coatings, oil-water separation, and low-friction fluid mechanics. Current methods for preparing super-hydrophobic surfaces mainly include template method, nanoparticle filling method, chemical etching method, electrochemical deposition method, and physical polishing method, etc. However, these methods often have problems such as complex preparation process, high cost, narrow application range, poor durability, etc. In particular, in practical applications, super-hydrophobic surfaces are easily affected by mechanical wear, ultraviolet radiation, high temperature, etc. and lose their hydrophobic properties, which seriously limits their practical application in industrial fields.

[0003] In recent years, self-repairing super-hydrophobic coatings have become a research hotspot. By storing migratory hydrophobic components in the material, when the surface layer is damaged, the stored hydrophobic components can migrate to the surface to restore the hydrophobic properties. However, current self-repairing super-hydrophobic coatings often use expensive chemical reagents, and the repair process requires external stimuli such as heating and light, which has low repair efficiency and is difficult to achieve real-time self-repairing.

[0004] Thermal power plant fly ash contains a large amount of hollow glass beads, some of which have magnetic characteristics, due to the presence of iron oxides (such as Fe3O4, γ-Fe2O3, etc.) on the surface or inside the beads. This type of magnetic hollow glass beads is usually considered as industrial waste, which has high disposal cost and causes environmental pollution. It is of great economic and environmental significance to effectively utilize this resource and convert it into high-value-added materials. The present application proposes a new method for preparing self-repairing super-hydrophobic coatings using magnetic hollow glass beads recovered from thermal power plant fly ash, which realizes the high-value utilization of industrial waste. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a self-repairing super-hydrophobic coating based on magnetic hollow glass beads and a preparation method thereof, which solves the problem of poor durability of super-hydrophobic coatings.

[0006] The present application can be realized by the following technical solutions: A preparation method of a self-repairing super-hydrophobic coating, comprising the following steps: Step 1: mixing an organic binder, a curing agent, and an organic solvent to prepare a bottom adhesive layer slurry; Step 2: uniformly coating the bottom adhesive layer slurry on the surface of a substrate and preliminary curing; Step 3, the magnetic hollow glass microspheres recovered and purified from fly ash of thermal power plant are made into a suspension and uniformly coated on the surface of the preliminarily solidified bottom adhesive layer; Step 4, a magnetic field is applied below the coating layer to make the magnetic hollow glass microspheres directional arrange and partially embed into the bottom adhesive layer, and then completely solidify to form a magnetic hollow glass microsphere roughness layer; Step 5, the surface of the magnetic hollow glass microsphere roughness layer is treated with a hydrochloric acid solution to selectively etch the ferromagnetic region of the microsphere surface to form a concave micro-nano structure; Step 6, hydrophobic nanoparticles, a hydrophobic modifier, a binder and an organic solvent are mixed to prepare a nanoparticle hydrophobic layer slurry; Step 7, the nanoparticle hydrophobic layer slurry is uniformly coated on the surface of the concave structure layer, so that the nanoparticles fill the concave structure and partially overflow on the surface, and finally completely solidify to obtain the self-repairing super-hydrophobic coating based on magnetic hollow glass microspheres.

[0007] Preferably, the bottom adhesive layer is solidified from raw materials of an organic binder, a curing agent and an organic solvent, and the mass ratio of the organic binder, the curing agent and the organic solvent is (10-30):(1-5):(50-85).

[0008] Preferably, the organic binder is one or a mixture of several of epoxy resin, polyurethane resin, silicone resin or acrylic resin.

[0009] Preferably, the magnetic hollow glass microsphere roughness layer is formed by directional arrangement of the magnetic hollow glass microspheres recovered and purified from fly ash of thermal power plant under an applied magnetic field, and the particle size of the magnetic hollow glass microspheres is 10-500 μm.

[0010] Preferably, the surface of the magnetic hollow glass microspheres contains a ferromagnetic material, including one or several of Fe3O4, γ-Fe2O3 or other iron-containing compounds.

[0011] Preferably, the concave structure layer is a micro-nano structure formed by selective etching of the ferromagnetic region of the surface of the magnetic hollow glass microspheres with a hydrochloric acid solution, and the etching depth is 0.5-10 μm.

[0012] Preferably, the nanoparticle hydrophobic layer is solidified from raw materials including hydrophobic nanoparticles, a hydrophobic modifier, a binder and an organic solvent; and the mass ratio of the hydrophobic nanoparticles, the hydrophobic modifier, the binder and the organic solvent is (1-15):(1-10):(0.5-5):(50-90).

[0013] Preferably, the hydrophobic nanoparticles are one or several of surface-modified silicon dioxide, titanium dioxide, aluminum oxide, zinc oxide or polytetrafluoroethylene powder, and the particle size is 5-100 nm.

[0014] Preferably, the hydrophobic modifier is one or more of long-chain alkylsilanes, perfluoroalkylsilanes, hexadecyltrimethoxysilanes, octadecyltrimethoxysilanes, or perfluorooctyltrimethoxysilanes.

[0015] The beneficial effects of this invention are: This invention achieves structural innovation and functional integration of a superhydrophobic coating by introducing magnetic hollow glass microspheres onto the surface of a resin matrix, resulting in outstanding comprehensive performance and industrial advantages. Using magnetic hollow glass microspheres recovered and purified from fly ash of thermal power plants as the main building blocks, an external magnetic field induces the microspheres to directionally accumulate and self-assemble on the resin surface, constructing a uniform and dense roughness base layer. After selective etching with hydrochloric acid, a regular concave micro-nano composite structure is formed on the surface of the microspheres. Furthermore, hydrophobically modified nanoparticles are embedded into this concave structure to form a hydrophobic layer with energy storage and migration functions. Through the synergistic effect of the above multi-level structure, the resulting coating simultaneously possesses high contact angle, low adhesion, excellent wear resistance, and significant anti-icing properties. The coating preparation process is simple, requires minimal equipment, and is easily implemented for large-area coating and mass production, demonstrating significant economic benefits and application value. Attached Figure Description

[0016] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0017] Figure 1 The basic structure of a self-healing superhydrophobic coating; Figure 2 This is a flowchart of the preparation process for a self-healing superhydrophobic coating; Figure 3 These are comparison images of the microstructure of magnetic hollow glass microspheres before and after etching. Figure 4 This is a scanning electron microscope image of the surface of the self-healing superhydrophobic coating; Figure 5 This is a contact angle diagram of a self-healing superhydrophobic coating; Figure 6 This describes the recovery of superhydrophobicity of a damaged superhydrophobic coating after 12 hours of standing. Detailed Implementation

[0018] The following provides a detailed description of the embodiments of the present invention: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and processes. However, the scope of protection of the present invention is not limited to the following embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions.

[0019] Example 1 Step 1: Mix 20g of epoxy resin (E-51) with 70g of acetone evenly, add 3g of phenolic amine epoxy curing agent and stir for 45 minutes to obtain the bottom adhesion layer slurry.

[0020] Step 2: Apply the base layer adhesive paste evenly to the surface of the stainless steel plate (coating amount is 0.1g / cm²), and cure at room temperature for 30 minutes to form a pre-cured base layer adhesive layer.

[0021] Step 3: The magnetic hollow glass microspheres (particle size 50-150μm) recovered and purified from the fly ash of thermal power plants are mixed with acetone at a mass ratio of 1:10 and ultrasonically dispersed for 20 minutes to obtain a uniform suspension.

[0022] Step 4: Uniformly coat the magnetic hollow glass microsphere suspension onto the surface of the pre-cured bottom adhesive layer, immediately apply a magnetic field (magnetic induction intensity of 0.2 Tesla) under the coating, and act for 15 minutes to orient the magnetic hollow glass microspheres and partially embed them into the bottom adhesive layer. Then cure at 80°C for 2 hours to form a rough layer of magnetic hollow glass microspheres.

[0023] Step 5: Immerse the coating obtained in Step 4 in a 2 mol / L hydrochloric acid solution and etch it at 40°C for 30 min to selectively dissolve the ferromagnetic regions on the surface of the magnetic hollow glass microspheres, forming a concave micro / nano structure. Then wash with deionized water and dry.

[0024] Step 6: Add 3g of hydrophobic modified silica nanoparticles (particle size 20-50nm) to 80g of ethanol, ultrasonically disperse for 30min, then add 5g of perfluorooctyltrimethoxysilane and 1g of polydimethylsiloxane (PDMS), stir for 4h to obtain the original slurry of the hydrophobic nanoparticle layer.

[0025] Step 7: Uniformly coat the nanoparticle hydrophobic layer slurry onto the surface of the concave structure layer (coating amount is 0.08 g / cm²), so that the nanoparticles fill the concave structure and partially overflow onto the surface. After drying at room temperature for 2 hours, cure at 50°C for 24 hours to obtain a self-healing superhydrophobic coating based on magnetic hollow glass microspheres.

[0026] Example 2 Step 1: Mix 15g of polyurethane resin and 65g of tetrahydrofuran evenly, add 2g of curing agent and stir for 40 minutes to obtain the bottom adhesion layer slurry.

[0027] Step 2: Apply the bottom adhesive layer paste evenly to the surface of the aluminum plate (coating amount is 0.08g / cm²) and cure at room temperature for 40 minutes to form a pre-cured bottom adhesive layer.

[0028] Step 3: Magnetic hollow glass microspheres (particle size 30-100μm) recovered and purified from thermal power plant fly ash are mixed with tetrahydrofuran at a mass ratio of 1:8, ultrasonically dispersed for 15 minutes, and two drops of blue dye are added to obtain a uniform suspension.

[0029] Step 4: Uniformly coat the magnetic hollow glass microsphere suspension onto the surface of the pre-cured bottom adhesive layer, immediately apply a magnetic field (magnetic induction intensity of 0.15 Tesla) under the coating, and act for 10 minutes to orient the magnetic hollow glass microspheres and partially embed them into the bottom adhesive layer. Then cure at 70°C for 2 hours to form a rough layer of magnetic hollow glass microspheres.

[0030] Step 5: Immerse the coating obtained in Step 4 in a 1.5 mol / L hydrochloric acid solution and etch it at 35°C for 20 min to selectively dissolve the ferromagnetic regions on the surface of the magnetic hollow glass microspheres, forming a concave micro / nano structure. Then wash with deionized water and dry.

[0031] Step 6: Add 2g of hydrophobic modified titanium dioxide nanoparticles (particle size 10-30nm) and 1g of polytetrafluoroethylene nanoparticles to 75g of ethanol, and ultrasonically disperse for 25min. Then add 4g of octadecyltrimethoxysilane and 0.8g of epoxy resin, and stir for 5h to obtain the original slurry of the hydrophobic nanoparticle layer.

[0032] Step 7: Uniformly coat the nanoparticle hydrophobic layer slurry onto the surface of the concave structure layer (coating amount is 0.07 g / cm²), so that the nanoparticles fill the concave structure and partially overflow onto the surface. After drying at room temperature for 2 hours, cure at 60°C for 12 hours to obtain a self-healing superhydrophobic coating based on magnetic hollow glass microspheres.

[0033] Example 3 Step 1: Mix 25g of silicone resin and 75g of toluene evenly, add 4g of catalyst and stir for 50 minutes to obtain the bottom adhesion layer slurry.

[0034] Step 2: Apply the bottom adhesive layer paste evenly to the surface of the glass substrate (coating amount is 0.12g / cm²) and cure at room temperature for 35 minutes to form a pre-cured bottom adhesive layer.

[0035] Step 3: The magnetic hollow glass microspheres (particle size 80-200μm) recovered and purified from the fly ash of thermal power plants are mixed with toluene at a mass ratio of 1:12 and ultrasonically dispersed for 25 minutes to obtain a uniform suspension.

[0036] Step 4: Uniformly coat the magnetic hollow glass microsphere suspension onto the surface of the pre-cured bottom adhesive layer, immediately apply a magnetic field (magnetic induction intensity of 0.3 Tesla) under the coating, and act for 20 minutes to orient the magnetic hollow glass microspheres and partially embed them into the bottom adhesive layer. Then cure at 90°C for 3 hours to form a rough layer of magnetic hollow glass microspheres.

[0037] Step 5: Immerse the coating obtained in Step 4 in a 3 mol / L hydrochloric acid solution and etch it at 50°C for 40 min to selectively dissolve the ferromagnetic regions on the surface of the magnetic hollow glass microspheres, forming a concave micro / nano structure. Then wash with deionized water and dry.

[0038] Step 6: Add 4g of hydrophobic modified alumina nanoparticles (particle size 15-40nm) to 70g of ethanol, ultrasonically disperse for 35min, then add 6g of heptadecafluorodecyltriethoxysilane and 1.2g of polydimethylsiloxane (PDMS), stir for 6h to obtain the original slurry of the hydrophobic nanoparticle layer.

[0039] Step 7: Uniformly coat the nanoparticle hydrophobic layer slurry onto the surface of the concave structure layer (coating amount is 0.09 g / cm²), so that the nanoparticles fill the concave structure and partially overflow onto the surface. After drying at room temperature for 3 hours, cure at 55°C for 24 hours to obtain a self-healing superhydrophobic coating based on magnetic hollow glass microspheres.

[0040] Comparative Example 1: The difference from Example 1 is that in step 4, after coating the magnetic hollow glass microsphere suspension, no magnetic field is applied; the remaining steps are the same as in Example 1.

[0041] Comparative Example 2: The difference from Example 1 is that the hydrochloric acid etching in step 5 is not performed; the remaining steps are the same as in Example 1.

[0042] Comparative Example 3: The difference from Example 1 is that no hydrophobic nanoparticle layer is coated. After the concave micro-nano structure is formed, it is directly dried and cured. Steps 1-5 are the same as in Example 1.

[0043] Step 1: Mix 20g of epoxy resin (E-51) with 70g of acetone evenly, add 3g of phenolic amine epoxy curing agent and stir for 45 minutes to obtain the bottom adhesion layer slurry.

[0044] Step 2: Apply the base layer adhesive paste evenly to the surface of the stainless steel plate (coating amount is 0.1g / cm²), and cure at room temperature for 30 minutes to form a pre-cured base layer adhesive layer.

[0045] Step 3: The magnetic hollow glass microspheres (particle size 50-150μm) recovered and purified from the fly ash of thermal power plants are mixed with acetone at a mass ratio of 1:10 and ultrasonically dispersed for 20 minutes to obtain a uniform suspension.

[0046] Step 4: Uniformly coat the magnetic hollow glass microsphere suspension onto the surface of the pre-cured bottom adhesive layer, immediately apply a magnetic field (magnetic induction intensity of 0.2 Tesla) under the coating, and act for 15 minutes to orient the magnetic hollow glass microspheres and partially embed them into the bottom adhesive layer. Then cure at 80°C for 2 hours to form a rough layer of magnetic hollow glass microspheres.

[0047] Step 5: Immerse the coating obtained in Step 4 in a 2 mol / L hydrochloric acid solution and etch it at 40°C for 30 min to selectively dissolve the ferromagnetic regions on the surface of the magnetic hollow glass microspheres, forming a concave micro / nano structure. Then, wash with deionized water and dry it, and cure it at 50°C for 24 h to obtain a superhydrophobic coating based on magnetic hollow glass microspheres.

[0048] Comparative Example 4: The difference from Example 1 is that ordinary non-magnetic hollow glass microspheres are used instead of magnetic hollow glass microspheres, and the remaining steps are the same as in Example 1.

[0049] Morphology analysis and performance testing 1. Surface morphology analysis: The surface morphology of the self-healing superhydrophobic coating was observed using scanning electron microscopy (SEM). The results showed that the coating surface has rich multi-level micro-nano structures. Magnetic hollow glass microspheres provide primary micron-level roughness, concave structures provide secondary micro-nano-level roughness, and hydrophobic nanoparticles provide tertiary nano-level roughness. The three levels of structures work together to form an ideal superhydrophobic surface.

[0050] 2. Surface hydrophobicity and self-healing properties The surface hydrophobicity of the self-healing superhydrophobic coating was tested according to GB / T 30693-2014. The larger the contact angle, the more hydrophobic the surface.

[0051] <90°, hydrophilic surface; 90-150°, hydrophobic surface; ≥150°, superhydrophobic surface.

[0052] Superhydrophobic surfaces typically exhibit high contact angles and low roll-off angles. The self-healing performance test method for self-healing superhydrophobic coatings is as follows: First, lightly sand the coating surface with sandpaper to reduce the water contact angle to approximately 120°. Then, allow it to stand at room temperature (25°C) and observe the recovery of the contact angle.

[0053] Table 1. Hydrophobic and self-healing properties of superhydrophobic coatings

[0054] 3. Corrosion resistance and anti-icing performance After immersing the self-healing superhydrophobic coating in 3.5% sodium chloride for 30 days, the contact angle was tested to evaluate the coating's corrosion resistance. The freezing time of water droplets on the surface coated with the self-healing superhydrophobic coating was tested at -15°C to evaluate the coating's anti-icing performance.

[0055] Table 2 Corrosion resistance and anti-icing properties of superhydrophobic coatings

[0056] Compared with the comparative example, the superhydrophobic coating prepared in Example 1 has better initial static contact angle and initial roll-off angle, and the coating has good hydrophobic properties. After sanding, the contact angle of the coating can spontaneously recover to 156°, showing obvious self-healing ability. These excellent properties are mainly due to the directional arrangement of magnetic hollow glass microspheres under the action of an external magnetic field, which constructs a uniform and dense micron-level rough structure, significantly reducing the actual contact area between the droplet and the solid. Furthermore, the concave micro-nano structure formed after hydrochloric acid etching further enhances the surface gas retention capacity, keeping the droplet in a stable Cassie state, significantly increasing the contact angle and reducing the roll-off angle. The embedded and partially overflowing hydrophobic nanoparticles construct a low surface energy outer layer and energy storage layer. When the surface is worn, the hydrophobic particles in the concave structure can migrate to the damaged area under the drive of surface energy, quickly recovering the hydrophobic properties and achieving spontaneous self-healing without external energy input.

[0057] Furthermore, the superhydrophobic coating prepared in Example 1 showed only a small decrease in contact angle and no significant corrosion or peeling after immersion in a 3.5 wt% sodium chloride solution for 30 days, indicating its excellent corrosion resistance. The significantly prolonged freezing time in Example 1 is attributed to the multi-level structure of the coating, including micron-sized magnetic hollow microspheres, concave micro / nano structures, and nanoparticle filling, which together form numerous closed or semi-closed air layers. These air layers provide thermal insulation, reducing the contact heat conduction rate between water droplets and the solid, thereby slowing down the freezing rate.

[0058] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a self-healing superhydrophobic coating based on magnetic hollow glass microspheres, characterized in that, The superhydrophobic coating includes an underlying adhesion layer, a magnetic hollow glass microsphere roughness layer, an indented structure layer, and a nanoparticle hydrophobic layer. The bottom adhesion layer is attached to the substrate surface. The roughness layer of the magnetic hollow glass microspheres is fixed on the surface of the bottom adhesion layer by directional arrangement. The concave structure layer is a micro-nano structure formed by etching the ferromagnetic region on the surface of the magnetic hollow glass microspheres. The hydrophobic nanoparticle layer fills and is fixed in the concave structure layer and partially overflows onto the coating surface.

2. The method for preparing a self-healing superhydrophobic coating based on magnetic hollow glass microspheres according to claim 1, characterized in that, The bottom adhesive layer is formed by curing organic adhesive, curing agent and organic solvent. The mass ratio of organic adhesive, curing agent and organic solvent is (10-30):(1-5):(50-85).

3. The method for preparing a self-healing superhydrophobic coating based on magnetic hollow glass microspheres according to claim 2, characterized in that, The organic binder is one or a mixture of several of epoxy resin, polyurethane resin, silicone resin or acrylic resin.

4. The method for preparing a self-healing superhydrophobic coating based on magnetic hollow glass microspheres according to claim 1, characterized in that, The roughness layer of the magnetic hollow glass microspheres is formed by fixing magnetic hollow glass microspheres, which are recovered and purified from fly ash of thermal power plants, after being oriented and arranged by an external magnetic field. The particle size of the magnetic hollow glass microspheres is 10-500 μm.

5. The method for preparing a self-healing superhydrophobic coating based on magnetic hollow glass microspheres according to claim 4, characterized in that, The surface of the magnetic hollow glass microspheres contains ferromagnetic materials, including one or more of Fe3O4, γ-Fe2O3, or other iron-containing compounds.

6. The method for preparing a self-healing superhydrophobic coating based on magnetic hollow glass microspheres according to claim 1, characterized in that, The concave structure layer is a micro-nano structure formed by selectively etching the ferromagnetic region on the surface of magnetic hollow glass microspheres with hydrochloric acid solution, with an etching depth of 0.5-10 μm.

7. The method for preparing a self-healing superhydrophobic coating based on magnetic hollow glass microspheres according to claim 1, characterized in that, The nanoparticle hydrophobic layer is formed by curing raw materials including hydrophobic nanoparticles, hydrophobic modifiers, binders and organic solvents; the mass ratio of the hydrophobic nanoparticles, hydrophobic modifiers, binders and organic solvents is (1-15):(1-10):(0.5-5):(50-90).

8. The method for preparing a self-healing superhydrophobic coating based on magnetic hollow glass microspheres according to claim 7, characterized in that, The hydrophobic nanoparticles are one or more of the following: surface-modified silica, titanium dioxide, aluminum oxide, zinc oxide, or polytetrafluoroethylene powder, with a particle size of 5-100 nm.

9. The method for preparing a self-healing superhydrophobic coating based on magnetic hollow glass microspheres according to claim 7, characterized in that, The hydrophobic modifier is one or more of the following: long-chain alkylsilane, perfluoroalkylsilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, or perfluorooctyltrimethoxysilane.

10. The method for preparing the self-healing superhydrophobic coating based on magnetic hollow glass microspheres according to any one of claims 1-9 is as follows: Step 1: Mix the organic adhesive, curing agent and organic solvent to prepare the base adhesive layer slurry; Step 2: Apply the bottom adhesive layer paste evenly to the substrate surface and allow it to cure initially; Step 3: The magnetic hollow glass microspheres recovered and purified from the fly ash of thermal power plants are made into a suspension and uniformly coated on the surface of the preliminarily cured bottom adhesion layer. Step 4: Apply a magnetic field under the coating to orient the magnetic hollow glass microspheres and partially embed them into the bottom adhesion layer, and then completely cure to form a magnetic hollow glass microsphere roughness layer. Step 5: Treat the surface of the roughness layer of the magnetic hollow glass microspheres with hydrochloric acid solution, selectively etch the ferromagnetic regions on the surface of the microspheres, and form a concave micro / nano structure. Step 6: Mix hydrophobic nanoparticles, hydrophobic modifier, binder and organic solvent to prepare nanoparticle hydrophobic layer slurry; Step 7: Uniformly coat the nanoparticle hydrophobic layer slurry onto the surface of the concave structure layer, so that the nanoparticles fill the concave structure and partially overflow onto the surface, and finally completely cure to obtain the self-healing superhydrophobic coating based on magnetic hollow glass microspheres.

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