Quaternary ammonium salt modified silicon dioxide nano-microsphere, preparation method thereof and anti-icing coating

Abstract

The invention discloses a quaternary ammonium salt modified silicon dioxide nano-microsphere, a preparation method thereof and an anti-icing coating, the chemical formula of the quaternary ammonium salt modified silicon dioxide nano-microsphere is as shown in formula (I): # imgabs 0 # chemical formula (I): R2 represents # imgabs 1 #; r < 1 > represents # imgabs < 2 >; n is equal to 2-6. Quaternary ammonium salt modified silicon dioxide nano-microspheres are used as raw materials to prepare the hydrophilic metal-based coating, the super-hydrophilic performance of the material is improved through the modified silicon dioxide nano-microspheres with quaternary ammonium salt groups, so that the quaternary ammonium salt groups are combined with water molecules to damage hydrogen bonds among the water molecules, non-freezing water is formed among media, and the purpose of reducing the freezing point is achieved; and meanwhile, the formed non-freezing water serves as a lubricating layer, so that the adhesive force between media is reduced, an ice layer is promoted to fall off due to the gravity of the ice layer, and the anti-freezing effect is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a quaternary ammonium salt modified silica nanosphere, a preparation method thereof, and an anti-icing coating. Background Art

[0002] In winter, the phenomenon of low-temperature icing is inevitable, which affects people's work, life and safety. The ice on the road and the ice on the front windshield of the car are very difficult to remove completely, directly affecting traffic safety; in low-temperature conditions, the water vapor in the atmosphere condenses into ice on the equipment, greatly affecting the normal use of the equipment, and causing economic losses or safety accidents in serious cases; the surface of long-distance transmission lines freezes, and its load will increase, resulting in line breaks or tower collapses, causing large-scale power outages and affecting people's work and life. Therefore, anti-icing engineering is an extremely important task.

[0003] With the development of atmospheric icing physics, nanotechnology and chemical synthesis technology, anti-icing coatings are an important measure in anti-icing engineering. Anti-icing coatings include superhydrophobic anti-icing coatings, photothermal coatings, hydrophilic anti-icing coatings and electrothermal composite coatings, all of which have a certain anti-icing effect: the ice adhesion of superhydrophobic coatings is relatively low, but the micro-nano structure on its surface is easily damaged, resulting in unstable performance; the delayed icing effect of photothermal coatings depends on the light intensity, and its performance will decrease significantly under no light or weak light conditions; the electrothermal composite coatings can quickly reduce the ice adhesion when powered on, but after power-off, the ice adhesion will return to a relatively high level; only the hydrophilic coatings mainly achieve passive anti-icing through physical adsorption and reducing ice adhesion, without the need for additional energy input (such as the light energy or electrical energy required by photothermal or electrothermal coatings), so it has more advantages in scenarios without energy supply. However, the hydrophilic anti-icing coatings have weak ability to delay the icing time and reduce the ice adhesion, resulting in poor anti-icing effect.

[0004] Therefore, it is necessary to provide a hydrophilic anti-icing coating with good anti-icing effect. Summary of the Invention

[0005] In view of this, the present application provides a quaternary ammonium salt modified silica nanosphere, a preparation method thereof, and an anti-icing coating, which are used to solve the problem of how to improve the anti-icing effect of hydrophilic anti-icing coatings.

[0006] To achieve the above technical purpose, the present application adopts the following technical solutions: In the first aspect, the present application provides a quaternary ammonium salt modified silica nanosphere, and its chemical formula is shown in formula (I):

[0007] Chemical formula (I) R 2 represents ; R 1 represents ; n = 2 - 6.

[0008] In a second aspect, the present application provides a method for preparing quaternary ammonium salt modified silica nanospheres, comprising the following steps: Mix a silicon ester, an alcohol, ammonia water, and water, and conduct a first heating reaction to obtain nano-silica; Using the nano-silica and γ-(2,3-epoxypropoxy)propyltrimethoxysilane as raw materials, conduct a second heating reaction to obtain a first intermediate product; Using the first intermediate product and polyethylenepolyamine as raw materials, conduct a third heating reaction to obtain a second intermediate product; Using the second intermediate product and 2,3-epoxypropyltrimethylammonium chloride as raw materials, conduct a fourth heating reaction to obtain the quaternary ammonium salt modified silica nanospheres.

[0009] Preferably, the silicon ester includes one or more of tetraethyl orthosilicate and tetrabutyl titanate; the alcohol includes ethanol; the polyethylenepolyamine includes one or more of tetraethylenepentamine, triethylenetetramine, diethylenetriamine, and pentaethylenehexamine.

[0010] Preferably, the molar ratio of the silicon ester, the alcohol, and the ammonia water is (1 - 3):(26 - 39):(0.13 - 0.19); the molar ratio of the water to the silicon grease is (0.39 - 0.57):(1 - 3); the temperature of the first heating is 50 - 60 °C.

[0011] Preferably, the molar ratio of the nano-silica to γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 10:(0.5 - 2); the temperature of the second heating reaction is 50 - 60 °C, and the time is 4 - 6 h.

[0012] Preferably, the molar ratio of γ-(2,3-epoxypropoxy)propyltrimethoxysilane to polyethylenepolyamine is 1:(1 - 1.2); the temperature of the third heating reaction is 50 - 60 °C, and the time is 4 - 6 h.

[0013] Preferably, the molar ratio of 2,3-epoxypropyltrimethylammonium chloride to polyethylenepolyamine is (5 - 7):1; the temperature of the fourth heating reaction is 70 - 80 °C, and the time is 4 - 6 h.

[0014] In a third aspect, the present application provides a hydrophilic metal-based anti-icing coating containing quaternary ammonium salt modified silica nanospheres, which, by mass, includes 1 - 3 parts of the quaternary ammonium salt modified silica nanospheres, 8 - 12 parts of an epoxy resin, and 5 - 8 parts of a curing agent.

[0015] In a fourth aspect, the present application provides an anti-icing composite coating prepared from the hydrophilic metal-based anti-icing coating.

[0016] Fifth aspect, the present application provides a method for preparing an anti-icing composite coating, including the following steps: Mix 1-3 parts of the quaternary ammonium salt-modified silica nanospheres, 8-12 parts of epoxy resin, and 5-8 parts of curing agent evenly, coat it on the metal surface, and after curing at room temperature, a hydrophilic metal-based coating is obtained.

[0017] The beneficial effects of the present application are as follows: The present application improves the superhydrophilic performance of the material through quaternary ammonium salt group-modified silica nanospheres, so that the quaternary ammonium salt groups combine with water molecules to break the hydrogen bonds between water molecules, form non-freezing water between media, achieve the purpose of lowering the freezing point, and at the same time, the formed non-freezing water serves as a lubricating layer, which is beneficial to reducing the adhesion force between media, promoting the ice layer to fall off under its own gravity, thereby achieving the anti-icing effect. Description of the Drawings

[0018] Figure 1 It is a schematic structural diagram of quaternary ammonium salt-modified silica nanospheres; Figure 2 It is an infrared spectrum diagram of quaternary ammonium salt-modified silica nanospheres; Figure 3 It is a particle size distribution diagram of quaternary ammonium salt-modified silica nanospheres; Figure 4 It is an XPS diagram of the anti-icing coating. Detailed Embodiments

[0019] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0020] The present application provides a quaternary ammonium salt-modified silica nanosphere, and its chemical formula is shown in formula (I):

[0021] Chemical formula (I) R 2 represents ; R 1 represents ; n = 2-6.

[0022] In this application, in the quaternary ammonium salt-modified silica nanospheres, the silica nanospheres are grafted with quaternary ammonium salts. As an organic metal salt, quaternary ammonium salts are white solids at room temperature, soluble in water, absorbent to water and moisture, and can directly absorb water and melt when exposed to air. The modified silica nanospheres with quaternary ammonium salt groups have superhydrophilic properties, which enable the quaternary ammonium salt groups to combine with water molecules to break the hydrogen bonds between water molecules, form non-freezing water between media, achieve the purpose of lowering the freezing point, and at the same time, the formed non-freezing water acts as a lubricating layer, which is beneficial to reducing the adhesion force between media and promoting the ice layer to fall off under its own gravity, thus achieving the anti-icing effect.

[0023] This application provides a preparation method of quaternary ammonium salt-modified silica nanospheres, which includes the following steps: S1. Mix silicate ester, alcohol, ammonia water, and water, and conduct a primary heating reaction to obtain nano-silica. S2. Use nano-silica and γ-(2,3-epoxypropoxy)propyltrimethoxysilane as raw materials, and conduct a secondary heating reaction to obtain a first intermediate product. S3. Use the first intermediate product and polyethylenepolyamine as raw materials, and conduct a tertiary heating reaction to obtain a second intermediate product. S4. Use the second intermediate product and 2,3-epoxypropyltrimethylammonium chloride as raw materials, and conduct a quaternary heating reaction to obtain the quaternary ammonium salt-modified silica nanospheres.

[0024] This application modifies nano-silica through step-by-step reactions and successfully grafts quaternary ammonium salts onto nano-silica.

[0025] In some embodiments, the silicate ester includes one or more of tetraethyl orthosilicate and tetrabutyl titanate; the alcohol includes ethanol; the polyethylenepolyamine includes one or more of tetraethylenepentamine, triethylenetetramine, diethylenetriamine, and pentaethylenehexamine.

[0026] In this embodiment, the polyethylenepolyamine of this application is used to control the n value (2 - 6). Tetraethylenepentamine, triethylenetetramine, diethylenetriamine, and pentaethylenehexamine are all homologues, which can control the chain length of the quaternary ammonium salt side chains grafted on the nano-silica microspheres and the number of hydrophilic groups. To expand the types of coatings, the silicate ester includes tetraethyl orthosilicate and tetrabutyl titanate, and tetrabutyl titanate can be used to prepare a photothermal coating. Taking tetraethyl orthosilicate as the silicate ester, ethanol as the alcohol, and tetraethylenepentamine as the polyethylenepolyamine as an example, the preparation process of the quaternary ammonium salt-modified silica nanospheres is as follows:

[0027] n = 4 In some embodiments, the molar ratio of silicate ester, alcohol, and ammonia water is (1 - 3):(26 - 39):(0.13 - 0.19); the molar ratio of water to silicate ester is (0.39 - 0.57):(1 - 3); the temperature of the first heating is 50 - 60°C.

[0028] In this embodiment, the amounts of ammonia water and deionized water will affect the synthesis rate and particle size of nano-silica. The particle size of the nano-silica microspheres will affect the subsequent reaction. However, if the particle size is too small, it is difficult to filter out, and it is difficult to form quaternary ammonium salt modified silica nano-microspheres.

[0029] In some embodiments, the molar ratio of nano-silica to γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 10:(0.5 - 2); the temperature of the second heating reaction is 50 - 60°C, and the time is 4 - 6 h.

[0030] In this embodiment, the amount of γ-(2,3-epoxypropoxy)propyltrimethoxysilane (KH560) will affect the content of hydrophilic groups, and thus affect the hydrophilicity of the product. Therefore, too much or too little γ-(2,3-epoxypropoxy)propyltrimethoxysilane will not improve the anti-icing effect well.

[0031] In some embodiments, the molar ratio of γ-(2,3-epoxypropoxy)propyltrimethoxysilane to polyethylene polyamine is 1:(1 - 1.2); the temperature of the third heating reaction is 50 - 60°C, and the time is 4 - 6 h.

[0032] In this embodiment, the amount of polyethylene polyamine will affect the content of hydrophilic groups, and thus affect the hydrophilicity of the product. Therefore, too much or too little polyethylene polyamine will not improve the anti-icing effect well.

[0033] In some embodiments, the molar ratio of 2,3-epoxypropyltrimethylammonium chloride to polyethylene polyamine is (5 - 7):1; the temperature of the fourth heating reaction is 70 - 80°C, and the time is 4 - 6 h.

[0034] In this embodiment, when the amount of γ-(2,3-epoxypropoxy)propyltrimethoxysilane is too large, the viscosity of the solution will increase, and the anti-icing performance of the coating will decrease. Too little γ-(2,3-epoxypropoxy)propyltrimethoxysilane will lead to a decrease in the hydrophilicity of the coating and a reduction in the anti-icing performance.

[0035] This application provides a hydrophilic metal-based anti-icing coating containing quaternary ammonium salt modified silica nano-microspheres, including 1 - 3 parts of quaternary ammonium salt modified silica nano-microspheres, 8 - 12 parts of epoxy resin, and 5 - 8 parts of curing agent.

[0036] In this application, an epoxy resin with excellent adhesion to metals is used as a film-forming substance, and silica nanospheres modified with quaternary ammonium salts are added and mixed with the epoxy resin and coated on the metal surface for curing to form an anti-icing coating, which improves the anti-icing effect. The reasons are as follows: Epoxy resin has excellent adhesion to metals, and the epoxy groups on the surface of the silica microspheres in this application are used to anchor themselves on the surface of the epoxy coating. The grafted multi-quaternary ammonium salt segments on the surface of the silica microspheres are used to absorb water and moisture, forming a super-hydrophilic coating surface, so that the quaternary ammonium salt groups in the coating combine with water molecules, breaking the hydrogen bonds between water molecules and forming a layer of unfrozen water between the coating and water, achieving the purpose of lowering the freezing point; at the same time, the unfrozen water serves as a lubricating layer between the condensed ice layer and the coating, which can reduce the adhesion between the two, promote the ice layer to reach a certain thickness, and fall off under the action of its own gravity, avoiding damage to power facilities, and improving the anti-icing effect in terms of reducing the adhesion of ice, prolonging the icing time, and improving the durability of the coating.

[0037] This application provides a method for preparing a hydrophilic metal-based anti-icing coating, which includes the following steps: Mix 1-3 parts of quaternary ammonium salt-modified silica nanospheres, 8-12 parts of epoxy resin, and 5-8 parts of curing agent evenly, coat them on the metal surface, and after curing at room temperature, a hydrophilic metal-based coating is obtained.

[0038] The method for preparing the hydrophilic metal-based anti-icing coating of this application is simple. After stirring and mixing evenly to remove air bubbles, it can be directly coated on the surface of a metal substrate (such as a steel sheet) to form a hydrophilic metal-based coating.

[0039] This application provides an application of a hydrophilic metal-based anti-icing coating in an environment below 0°C.

[0040] The following further illustrates this solution through specific examples.

[0041] Example 1 A method for preparing quaternary ammonium salt-modified silica nanospheres includes the following steps: S1. Add 10 g of tetraethyl orthosilicate to 100 ml of ethanol, sequentially add 1.5 ml of ammonia water and 2.5 ml of water, heat to 60°C for a first heating reaction for 4 h, and obtain 2.23 g of nano-silica; S2. Take 1.5 g of silica and ultrasonically disperse it in a solution with an alcohol-water ratio of 1:1 of 50 ml, add 0.7 g of KH560, heat to 60°C for a second heating reaction for 4 h to obtain a first intermediate product; S3. Add 0.43 g of tetraethylenepentamine to the first intermediate product and carry out a third heating reaction at 60°C for 4 h to obtain a second intermediate product; S4. In the second intermediate product, add 2.07 g of 2,3-epoxypropyltrimethylammonium chloride, heat up to 70 °C and carry out four heating reactions for 4 h, then perform rotary evaporation. After suction filtration, washing, and drying, the quaternary ammonium salt modified silica nanospheres are obtained.

[0042] The chemical formula of the obtained quaternary ammonium salt modified silica nanospheres is:

[0043] R 2 represents ; R 1 represents ; n = 4.

[0044] Example 2 A preparation method of quaternary ammonium salt modified silica nanospheres, comprising the following steps: S1. Add 10 g of tetraethyl orthosilicate to 100 ml of ethanol, sequentially add 1.5 ml of ammonia water and 2.5 ml of water, heat up to 60 °C and carry out a first heating reaction for 4 h to obtain 2.23 g of nano-silica; S2. Take 1.5 g of silica and ultrasonically disperse it in a 50 ml solution with an alcohol-water ratio of 1:1, add 0.7 g of KH560, heat up to 60 °C and carry out a second heating reaction for 4 h to obtain a first intermediate product; S3. In the first intermediate product, add 0.38 g of tetraethylenepentamine and carry out a third heating reaction at 60 °C for 4 h to obtain a second intermediate product; S4. In the second intermediate product, add 1.83 g of 2,3-epoxypropyltrimethylammonium chloride, heat up to 70 °C and carry out a fourth heating reaction for 4 h, then perform rotary evaporation. After suction filtration, washing, and drying, the quaternary ammonium salt modified silica nanospheres are obtained.

[0045] Example 3 A preparation method of a hydrophilic metal-based anti-icing coating, comprising the following steps: Mix 2.0 g of the quaternary ammonium salt modified silica nanospheres prepared in Example 1 with 10 g of epoxy resin and 10 g of curing agent evenly, coat it on a steel sheet, and cure it at room temperature of 25 °C to obtain a hydrophilic metal-based coating.

[0046] Example 4 A preparation method of a hydrophilic metal-based anti-icing coating, comprising the following steps: Mix 3.5 g of the quaternary ammonium salt modified silica nanospheres prepared in Example 1 with 5 g of epoxy resin and 5 g of curing agent evenly, coat it on a steel sheet, and cure it at room temperature of 25 °C to obtain a hydrophilic metal-based coating.

[0047] Example 5 A preparation method of a hydrophilic metal-based anti-icing coating, comprising the following steps: Mix 2.0 g of the quaternary ammonium salt-modified silica nanospheres prepared in Example 2 with 10 g of epoxy resin and 10 g of curing agent evenly, coat it on a steel sheet, and cure it at room temperature of 25 °C to obtain a hydrophilic metal-based coating.

[0048] Example 6 S1. Add 10 g of tetraethyl orthosilicate to 100 ml of ethanol, sequentially add 1.5 ml of ammonia water and 2.5 ml of water, heat up to 60 °C and carry out a first heating reaction for 4 h to obtain 2.23 g of nano-silica; S2. Take 1.5 g of silica and ultrasonically disperse it in a 50 ml solution with an alcohol-to-water ratio of 1:1, add 0.7 g of KH560, heat up to 60 °C and carry out a second heating reaction for 4 h to obtain a first intermediate product; S3. Add 0.21 g of diethylenetriamine to the first intermediate product, and carry out a third heating reaction at 60 °C for 4 h to obtain a second intermediate product; S4. Add 1.31 g of 2,3-epoxypropyltrimethylammonium chloride to the second intermediate product, heat up to 70 °C and carry out a fourth heating reaction for 4 h, carry out rotary evaporation, suction filtration, washing and drying to obtain quaternary ammonium salt-modified silica nanospheres.

[0049] S5. Mix 2.0 g of the prepared quaternary ammonium salt-modified silica nanospheres with 10 g of epoxy resin and 10 g of curing agent evenly, coat it on a steel sheet, and cure it at room temperature of 25 °C to obtain a hydrophilic metal-based coating.

[0050] Comparative Example 1 A preparation method of a coating, the other contents are the same as those in Example 1, the difference is that it does not include adding quaternary ammonium salt-modified silica nanospheres.

[0051] Comparative Example 2 A preparation method of a coating, the other contents are the same as those in Example 1, the difference is that when synthesizing quaternary ammonium salt-modified silica nanospheres, 30% more KH560 is added.

[0052] Comparative Example 3 A preparation method of a coating, the other contents are the same as those in Example 1, the difference is that when synthesizing quaternary ammonium salt-modified silica nanospheres, 30% more tetraethylenepentamine is added.

[0053] Comparative Example 4 A preparation method of a coating, the other contents are the same as those in Example 1, the difference is that when synthesizing quaternary ammonium salt-modified silica nanospheres, 30% more ammonia water is added.

[0054] Testing and Evaluation The infrared spectrum of the quaternary ammonium salt modified silica nanospheres obtained in Test Example 1 is as follows Figure 2 shown; the average particle size of the quaternary ammonium salt modified silica nanospheres was measured. The particle size affects the synthesis rate. If the particle size is too small, the synthesized nano-silica cannot be filtered out during the synthesis process, and subsequent experiments cannot be carried out. If the particle size of the quaternary ammonium salt modified silica nanospheres is too large, when preparing a hydrophilic coating, the hydrophilic groups on the coating surface will decrease, resulting in a decline in the anti-icing performance. The results are shown in Table 1. The particle size distribution diagram of the quaternary ammonium salt modified silica nanospheres in Example 1 is as follows Figure 3 shown.

[0055] Table 1 Average particle size and dispersion index of different quaternary ammonium salt modified silica nanospheres

[0056] The XPS diagram of the hydrophilic metal-based anti-icing coating obtained in Test Example 3 was tested, and the results are as follows Figure 4 shown. The surface element content analysis results of the hydrophilic metal-based anti-icing coating obtained in Example 3 are shown in Table 2.

[0057] Table 2 Surface element content analysis results of the hydrophilic metal-based anti-icing coating obtained in Example 3

[0058] As can be seen from Table 1, the proportion of nitrogen element in the hydrophilic metal-based anti-icing coating obtained in Example 3 is more than the theoretical content, indicating that the quaternary ammonium salt has been successfully grafted and grown on the coating surface. The silicon element content is lower than the theoretical content, indicating that part of the silica is buried in the epoxy resin. The oxygen element is also lower than the theoretical value, further indicating that the silica is buried at the bottom, and part of the oxygen element is covered by the quaternary ammonium salt, indicating that a large amount of quaternary ammonium salt accumulates on the coating surface. The hydrophilic metal-based anti-icing coating of Example 3 was successfully prepared.

[0059] Using a steel sheet as a blank control, the anti-icing performance of the coatings obtained in Examples 3-5 and Comparative Examples 1-4 was tested: different coatings were placed in a freezer at -5°C for a freezing experiment. The ice formation time was measured, and the amount of water droplets and the contact area between the water droplets and the coating and the steel sheet were controlled. A fiber cloth was placed on the steel sheet, and a controlled amount of water was dripped onto it. After ice formation, a tensile tester was used to measure the maximum tensile force between the fiber cloth and the steel sheet as a reference for ice adhesion. The adhesion between the ice layer and the coating and the adhesion between the ice layer and the steel sheet are shown in Table 3.

[0060] Table 3 Performance test results of different coatings

[0061] The results show that the ice condensation time of the hydrophilic metal-based anti-icing coating prepared in this application is delayed, and the adhesion between the ice layer and the coating is significantly decreased compared with the adhesion between the ice layer and the iron sheet, indicating good anti-icing performance.

[0062] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A quaternary ammonium salt modified silica nanosphere, characterized in that: Its chemical formula is shown in formula (I): Chemical formula (I) R2 stands for ; R1 stands for ; n=2-6.

2. A method for preparing quaternary ammonium salt-modified silica nanospheres as claimed in claim 1, characterized in that: The following steps are involved: Mixing silicon ester, alcohol, ammonia water and water, and performing a heating reaction to obtain nano silicon dioxide; Using the nano-silicon dioxide and γ-(2,3-epoxypropoxy)propyltrimethoxysilane as raw materials, a secondary heating reaction is performed to obtain a first intermediate product; Using the first intermediate product and polyethylene polyamine as raw materials, performing heating reaction three times to obtain a second intermediate product; The second intermediate product and 2,3-epoxypropyltrimethylammonium chloride are used as raw materials and subjected to four heating reactions to obtain the quaternary ammonium salt-modified silica nanospheres.

3. The method for preparing quaternary ammonium salt modified silicon dioxide nano-microspheres according to claim 2, characterized in that The silicone ester includes one or more of ethyl orthosilicate and tetrabutyl titanate; the alcohol includes ethanol; and the polyethylene polyamine includes one or more of tetraethylene pentamine, triethylene tetramine, diethylene triamine, pentaethylene hexamine, and hexaethylene heptamine.

4. The method for preparing quaternary ammonium salt modified silicon dioxide nano-microspheres according to claim 2, characterized in that: The molar ratio of silicone ester, alcohol and ammonia water is (1-3): (26-39): (0.13-0.19); the molar ratio of water to silicone ester is (0.39-0.57): (1-3); and the temperature of the first heating is 50-60°C.

5. The method for preparing quaternary ammonium salt modified silicon dioxide nano-microspheres according to claim 2, characterized in that, The molar ratio of the nano-silicon dioxide to γ-(2,3-epoxypropoxy)propyltrimethoxysilane is 10:(0.5-2); the temperature of the secondary heating reaction is 50-60° C., and the time is 4-6 hours.

6. The method for preparing quaternary ammonium salt modified silicon dioxide nano-microspheres according to claim 2, characterized in that, The molar ratio of the γ-(2,3-epoxypropoxy)propyltrimethoxysilane to the polyethylene polyamine is 1:(1-1.2); the temperature of the three heating reactions is 50-60° C., and the time is 4-6 hours.

7. The method for preparing quaternary ammonium salt modified silicon dioxide nanospheres according to claim 2, characterized in that: The molar ratio of the 2,3-epoxypropyltrimethylammonium chloride to the polyethylene polyamine is (5-7):1; the temperature of the four heating reactions is 70-80°C and the time is 4-6 hours.

8. A hydrophilic metal-based anti-icing coating comprising the quaternary ammonium salt-modified silica nanospheres as claimed in claim 1, characterized in that: The composition comprises, by weight, 1 to 3 parts of the quaternary ammonium salt-modified silica nanospheres, 8 to 12 parts of epoxy resin, and 5 to 8 parts of a curing agent.

9. An anti-icing composite coating prepared from the hydrophilic metal-based anti-icing coating according to claim 8.

10. A method for preparing the anti-icing composite coating according to claim 9, characterized in that: The method comprises the following steps: uniformly mixing 1-3 parts of the quaternary ammonium salt modified silicon dioxide nano-microspheres, 8-12 parts of epoxy resin and 5-8 parts of curing agent, coating the mixture on the metal surface and curing the mixture at room temperature to obtain a hydrophilic metal-based coating.

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