WO2020259393A1

WO2020259393A1 - Mechanically durable super-hydrophobic nano coating and preparation method thereof

Info

Publication number: WO2020259393A1
Application number: PCT/CN2020/096912
Authority: WO
Inventors: 吴楠; 吴彬瑞; 彭超义; 江大志; 杨金水; 尹昌平; 邢素丽; 鞠苏
Original assignee: 国防科技大学
Priority date: 2019-06-28
Filing date: 2020-06-19
Publication date: 2020-12-30
Also published as: CN110172292A; CN110172292B

Abstract

Provided are a mechanically durable super-hydrophobic nano coating and a preparation method thereof, wherein the nano coating takes a nanofiber membrane as a framework reinforcement phase, and resin slurry as a matrix phase; the resin slurry includes resin slurry I and resin slurry II; the resin slurry I is a mixture of a hydrophobic modified epoxy resin, nano particles and a curing agent; the resin slurry II is a mixture of a hydrophobic modified epoxy resin and a curing agent; the preparation method comprises preparing the resin slurry, preparing a substrate coated with the resin slurry II, preparing the nanofiber membrane impregnated with the resin slurry I, stacking the impregnated nanofiber membrane on the substrate coated with the resin slurry II, heating and curing, to obtain the mechanically durable super-hydrophobic nano coating. The preparation method has advantages of simple process and low cost, and the prepared nano coating has excellent mechanical durability.

Description

Mechanically durable super-hydrophobic nano coating and preparation method thereof

This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on June 28, 2019, the application number is 201910574876.X, and the invention title is "a mechanically durable superhydrophobic nano coating and its preparation method". The entire content is incorporated into this application by reference.

Technical field

The invention relates to the technical field of coating preparation, in particular to a mechanically durable superhydrophobic nano coating and a preparation method thereof.

Background technique

The superhydrophobic phenomenon with a contact angle greater than 150° and a rolling angle less than 10° has attracted widespread attention in recent years. It has a strong application background in the fields of self-cleaning, anti-icing, and oil-water separation. Studies have shown that the preparation of superhydrophobic surfaces usually needs to meet two conditions: low surface energy and surface micro-nano secondary structure.

At present, most superhydrophobic materials face the same problem, that is, poor durability, especially mechanical durability. The main reason is that the superhydrophobic surface requires a certain micro-nano secondary structure to achieve, and the strength of such fine structures is usually low. Poor mechanical durability means that the super-hydrophobic surface is liable to lose super-hydrophobic performance under external mechanical impact. Therefore, improving the durability of superhydrophobic coatings is of great significance to its practical application.

Summary of the invention

The invention provides a mechanically durable super-hydrophobic nano coating and a preparation method thereof, which are used for overcoming defects such as poor mechanical durability of the super-hydrophobic coating in the prior art and realizing excellent mechanical durability of the super-hydrophobic nano coating.

To achieve the above objective, the present invention proposes a mechanically durable superhydrophobic nano-coating, the nano-coating uses a nanofiber membrane as a framework reinforcement phase and a resin slurry as a matrix phase;

The resin slurry includes resin slurry I and resin slurry II; the resin slurry I is a mixture of hydrophobically modified epoxy resin, nanoparticles, curing agent and diluent; the resin slurry II is a hydrophobic modified Mixture of epoxy resin, curing agent and diluent;

The nanofiber membrane is one of polyvinylidene fluoride fiber membrane, polyacrylonitrile fiber membrane, polystyrene fiber membrane, silicon oxycarbon fiber membrane, silicon carbide fiber membrane, alumina fiber membrane and zirconia fiber membrane.

In order to achieve the above objective, the present invention also provides a method for preparing a mechanically durable super-hydrophobic nano-coating, which includes the following steps:

(1) Add the mixture of hydrophobically modified epoxy resin, nanoparticles and curing agent to the diluent, and use ultrasonic emulsification and high-speed shear to make the nanoparticles, curing agent and hydrophobically modified epoxy resin uniformly mixed to obtain resin slurry料Ⅰ;

Add the hydrophobically modified epoxy resin and curing agent to the diluent, stir and mix uniformly to obtain resin slurry II;

(2) Coating the resin slurry II on the substrate and curing it at 80°C for 10-40 minutes;

At the same time, immerse the nanofiber membrane in the resin slurry I, and then volatilize to remove the diluent in the resin slurry I in the nanofiber membrane, and repeat the above dipping and volatilization process several times;

(3) Laying the impregnated nanofiber membrane on the side of the substrate coated with the resin slurry II, and heating and curing to obtain a mechanically durable super-hydrophobic nano coating.

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

1. The mechanically durable super-hydrophobic nano-coating provided by the present invention uses nanofiber membrane as the framework reinforcement phase and resin slurry as the matrix phase; the resin slurry includes resin slurry I and resin slurry II; Slurry I is a mixture of hydrophobically modified epoxy resin, nanoparticles, curing agent and diluent; said resin slurry II is a mixture of hydrophobically modified epoxy resin, curing agent and diluent; said nanofiber membrane is One of polyvinylidene fluoride fiber membranes, polyacrylonitrile fiber membranes, polystyrene fiber membranes, silicon-oxycarbon fiber membranes, silicon carbide fiber membranes, alumina fiber membranes, and zirconia fiber membranes. The mechanically durable super-hydrophobic nano-coating uses nano-fiber membranes as the skeleton-reinforcing phase of the super-hydrophobic coating. It uses micro-level holes and nanoparticles between nano-fibers to construct a micro-nano secondary structure, and uses hydrophobic epoxy resin to make nano-fibers The surface of membranes and nanoparticles have low surface energy, which makes their surface super-hydrophobic. At the same time, the multiphase reinforced nanocomposite similar to the "reinforced concrete" structure formed by the combination of nanofiber membranes, hydrophobic epoxy resins and nanoparticles has excellent mechanical durability, so that the superhydrophobic nano coating has a higher The practical value.

2. The method for preparing the mechanically durable super-hydrophobic nano-coating provided by the present invention includes the preparation of resin slurry, the preparation of substrates coated with resin slurry II and the preparation of nanofiber membranes impregnated with resin slurry I. The film is stacked on a substrate coated with resin slurry II, and heated and cured to obtain a mechanically durable super-hydrophobic nano-coating. The preparation method has simple process and low cost, and the prepared product has excellent mechanical durability.

Description and drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, without creative work, other drawings can be obtained based on the structures shown in these drawings.

Figure 1a is a photo of the surface micro-topography of the superhydrophobic coating obtained in Example 1;

Figure 1b is a hydrophobic picture of the surface of the superhydrophobic coating obtained in Example 1;

Figure 2a is a photo of the surface micro-topography of the super-hydrophobic coating obtained in Example 1 after being polished 60 times with 600 mesh sandpaper;

Figure 2b is a hydrophobic picture of the superhydrophobic coating obtained in Example 1 after being polished 60 times with 600 mesh sandpaper;

Figure 3 is a morphology diagram of the silicon carbide fiber used in Example 3;

Figure 4a is a photo of the surface micro-topography of the super-hydrophobic coating obtained in Example 3 after being polished 60 times with 600 mesh sandpaper;

Figure 4b is a hydrophobic picture of the superhydrophobic coating obtained in Example 3 after being polished 60 times with 600 mesh sandpaper;

Figure 5a is a photo of the surface micro-topography of the coated tape in Comparative Example 1 after being stripped five times;

Figure 5b is a hydrophobic picture of the coated tape in Comparative Example 1 after being stripped 5 times;

Figure 6a is an optical photo of the inside of the coating in Comparative Example 2;

Figure 6b is a photo of the surface micro-topography of the coating in Comparative Example 2.

The realization of the objectives, functional characteristics and advantages of the present invention will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but they must be based on what can be achieved by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that this combination of technical solutions It does not exist and does not fall within the scope of protection required by the present invention.

Without special instructions, the drugs/reagents used are all commercially available.

The present invention provides a mechanically durable super-hydrophobic nano-coating, wherein the nano-coating uses a nanofiber membrane as a skeleton reinforcement phase and a resin slurry as a matrix phase;

The nanofiber membrane is one of polyvinylidene fluoride fiber membrane, polyacrylonitrile fiber membrane, polystyrene fiber membrane, silicon oxycarbon fiber membrane, silicon carbide fiber membrane, alumina fiber membrane and zirconia fiber membrane. Choosing a nanofiber membrane with small fiber diameter, high porosity, and good flexibility is beneficial to improve the hydrophobicity and mechanical durability of the superhydrophobic nano coating.

Preferably, the average thickness of the nanofiber membrane is 10-30 μm, preferably 10-20 μm; the average fiber diameter is 200-600 nm, preferably 200-500 nm.

The superhydrophobic coating of the present invention uses nanofiber membranes as the skeleton reinforcement phase of the superhydrophobic coating, uses micron-level pores and nanoparticles between nanofibers to jointly construct a micro-nano secondary structure, and uses hydrophobic epoxy resin to make the nanofiber membrane and The surface of the nanoparticles has low surface energy, so that the surface has superhydrophobic properties. At the same time, the multiphase reinforced nanocomposite with a structure similar to "reinforced concrete" formed by the combination of nanofiber membrane, hydrophobically modified epoxy resin and nanoparticles has excellent mechanical durability.

The present invention also provides a method for preparing a mechanically durable superhydrophobic nano coating, which includes the following steps:

Preferably, the hydrophobically modified epoxy resin is one of hydrophobically modified E-51 epoxy resin, E-44 epoxy resin and E-42 epoxy resin. Choosing a suitable resin is conducive to the hydrophobicity of the final product. The improvement; The nanoparticles are one of silica nanoparticles, titanium dioxide nanoparticles and aluminum oxide nanoparticles. Nanoparticles work together with hydrophobically modified epoxy resin and nanofiber membranes to greatly improve the coating’s Mechanical durability; the curing agent is at least one of diethylenetriamine, diaminodiphenylmethane, polyetheramine D-230 and polyetheramine D-400. Choose a suitable curing agent to form a "reinforced steel "Concrete" has a firm structure; the diluent is at least one of ethyl acetate, ethanol, N,N-dimethylformamide, dimethyl sulfoxide, cyclohexane and acetone, so that the curing agent can be fully dissolved and The hydrophobically modified epoxy resin and/or nanoparticles are uniformly dispersed.

Preferably, in the resin slurry I, the mass ratio of the hydrophobically modified epoxy resin to the nanoparticles is (1.5-3):1; the usage amount of the curing agent is the same as the amine equivalent of the curing agent used and the ring The epoxy value of the oxygen resin is related; the mass ratio of the diluent to the total mass of the hydrophobically modified epoxy resin, nanoparticles and curing agent is (3～5):1, which is beneficial to the hydrophobically modified epoxy resin, nanoparticles and The curing agent is evenly mixed, so that the mechanical durability of the final prepared product is more excellent.

Preferably, in the resin slurry II, the mass ratio of the hydrophobically modified epoxy resin and the curing agent has a corresponding relationship; the mass ratio of the diluent to the total mass of the hydrophobically modified epoxy resin and the curing agent is ( 0.5～1.5):1, which is conducive to the uniform mixing of hydrophobically modified epoxy resin, nanoparticles and curing agent, so that the final prepared product has better mechanical durability.

Preferably, the average particle diameter of the nanoparticles is 20-50 nm. When preparing superhydrophobic materials, it is better to need a certain nano-scale structure to increase its rough structure and hydrophobic properties.

(2) Coating resin slurry II on the substrate and curing it at 80℃ for 10-40min; the semi-curing process can completely volatilize the solvent and increase the viscosity of the resin to a certain extent to ensure that it will not be The substrate flows out due to gravity and other reasons.

At the same time, immerse the nanofiber membrane in the resin slurry I, and then volatilize to remove the diluent in the resin slurry I in the nanofiber membrane, and repeat the above dipping and volatilization process 3-8 times;

Preferably, the coating amount for coating the resin slurry II on the substrate is 0.003 to 0.014 g/cm ² , preferably 0.005 to 0.012 g/cm ² . If the coating amount is too large, the resin slurry II will completely penetrate the nanofiber membrane and lose its super-hydrophobic performance; if the coating amount is too small, the thickness of the underlying resin reversely infiltrating the nanofiber membrane is small, resulting in poor durability of the nano coating.

Preferably, the immersion time is 3 to 5 minutes, and the temperature is 20 to 30°C, which is beneficial for the nanoparticles and the hydrophobic resin to fully penetrate into the nanofiber membrane without damaging the original mechanical properties of the nanofiber membrane. The volatilization is natural volatilization at room temperature; the number of repeated impregnation and volatilization processes is 3-8 times, preferably 3-5 times, so that the nanoparticles and the hydrophobic resin can fully penetrate the nanofiber membrane.

Preferably, the heating and curing procedure is 70-85° C., 1 to 2 hours in the first stage; 90-100° C., 1 to 2 hours in the second stage. Too low temperature and too short time will lead to incomplete curing; too high temperature and too long time will cause the coating to crack.

Example one

This embodiment provides a mechanically durable super-hydrophobic nano-coating with a coating thickness of about 0.4mm; the nano-coating uses polyacrylonitrile fiber membrane as the framework reinforcement phase, the average fiber diameter is 200 nm, and the average fiber membrane thickness is 12μm; resin slurry as the matrix phase; the resin slurry includes resin slurry I and resin slurry II; the resin slurry I is hydrophobically modified E-51 epoxy resin, aluminum oxide nanoparticles and A mixture of polyetheramine D-230; the resin slurry II is a mixture of hydrophobically modified E-51 epoxy resin and polyetheramine D-230.

This embodiment also provides a method for preparing a mechanically durable super-hydrophobic nano-coating, the specific steps are:

(1) Add a mixture of 10g hydrophobically modified E-51 epoxy resin, 5g aluminum oxide nanoparticles and 3g polyetheramine D-230 to 75g ethyl acetate diluent, and use ultrasonic emulsification and high-speed shear to make Aluminum oxide nanoparticles, polyetheramine D-230 and hydrophobically modified E-51 epoxy resin are mixed uniformly to obtain resin slurry I;

Add 5g of hydrophobically modified E-51 epoxy resin and 1.5g of polyetheramine D-230 to 5g of ethyl acetate diluent, stir and mix uniformly to obtain resin slurry II;

(2) Coating resin slurry II on the substrate with a coating surface density of 0.005g/cm ² and curing it at 80°C for 20 minutes;

At the same time, immerse the polyacrylonitrile fiber membrane in the resin slurry I, and then volatilize the ethyl acetate in the resin slurry I in the polyacrylonitrile fiber membrane, repeat the above-mentioned dipping and volatilization process several times 3 times;

(3) Stack the impregnated polyacrylonitrile fiber membrane on the side of the substrate coated with the resin slurry II, and heat and cure: 80°C for 1 hour, 100°C for 1 hour to obtain a mechanically durable superhydrophobic nano coating.

The surface of the super-hydrophobic nano-coating is uniform nano-particles, as shown in Figure 1a, the water contact angle is 156.8°; after 60 times of sanding with 600 grit sandpaper, the contact angle drops to 147.4°, and the surface of the nanofiber skeleton and nanoparticles are exposed And resin to build a new micro-nano structure, as shown in Figure 2a; after 90 times of sanding with 360 grit sandpaper, the contact angle dropped to 146.6°; after 50 grit impact tests, the contact angle of the superhydrophobic composite material dropped to 142.2 °; The hydrophobic photos of Figures 1b and 2b show that the superhydrophobic nano coating provided by this embodiment has strong hydrophobicity. The above results show that the super-hydrophobic nano-coating using polyacrylonitrile nanofiber membrane as the skeleton can maintain super-hydrophobicity under the conditions of friction and dynamic impact, indicating that this type of super-hydrophobic nanocomposite has good mechanical durability.

Example two

This embodiment provides a mechanically durable super-hydrophobic nano-coating with a thickness of about 0.4mm; the nano-coating uses a polyvinylidene fluoride fiber membrane as a skeleton, with an average fiber diameter of 400 nm and an average thickness of 25 μm. The resin slurry is the matrix phase; the resin slurry includes resin slurry I and resin slurry II; the resin slurry I is hydrophobically modified E-51 epoxy resin, titanium dioxide nanoparticles and diethylene triamine The resin slurry II is a mixture of hydrophobically modified E-51 epoxy resin and diethylene triamine.

(1) Add a mixture of 10g hydrophobically modified E-51 epoxy resin, 4g titanium dioxide nanoparticles and 3g diethylenetriamine to 75g cyclohexane diluent, and use ultrasonic emulsification and high-speed shear to make titanium dioxide nanoparticles, two Ethylene triamine and hydrophobically modified E-51 epoxy resin are mixed uniformly to obtain resin slurry I;

Add 5g of hydrophobically modified E-51 epoxy resin and 1.5g of diethylenetriamine to 5g of cyclohexane diluent, stir and mix uniformly to obtain resin slurry II;

(2) Coating resin slurry II on the substrate with a coating surface density of 0.01g/cm ² and curing at 90°C for 15 minutes;

At the same time, immerse the polyvinylidene fluoride fiber membrane in the resin slurry I, and then volatilize to remove the cyclohexane in the resin slurry I in the polyvinylidene fluoride fiber membrane, and repeat the above-mentioned dipping and volatilization process several times 5 times;

(3) Lay the impregnated polyvinylidene fluoride fiber membrane on the side of the substrate coated with the resin slurry II, and heat and cure: 1.5h at 75°C and 1h at 100°C to obtain a mechanically durable superhydrophobic nano-coating Floor.

The surface of the super-hydrophobic nano-coating is uniform nanoparticles with an average water contact angle of 155.2°; after 60 times of sanding with 600 grit sandpaper, the contact angle drops to 150.3°, and the surface of the nanofiber skeleton, nanoparticles and resin are exposed; use 360 After 100 times of sandpaper grinding, the surface water contact angle was 148.6°; after 10 times of adhesion with 3M tape, the surface water contact angle was 147.6°; after 50 grit impact tests, the contact angle of the superhydrophobic composite material was 148.2° The above results show that the super-hydrophobic nano-coating using polyvinylidene fluoride nanofiber membrane as the framework can maintain super-hydrophobicity under friction and dynamic impact conditions, indicating that this type of super-hydrophobic nanocomposite has good durability.

Example three

This embodiment provides a mechanically durable super-hydrophobic nano-coating with a thickness of about 0.4mm; the nano-coating uses a silicon carbide fiber membrane as a skeleton, the average fiber diameter is 500nm, the average fiber membrane thickness is 20μm, and the fiber The morphology is shown in Figure 3; the resin slurry is used as the matrix phase; the resin slurry includes resin slurry I and resin slurry II; the resin slurry I is hydrophobically modified E-42 epoxy resin, two A mixture of silicon oxide nanoparticles and polyetheramine D-400; the resin slurry II is a mixture of hydrophobically modified E-42 epoxy resin and polyetheramine D-400.

(1) Add a mixture of 10g hydrophobically modified E-42 epoxy resin, 3.5g silica nanoparticles and 3g polyetheramine D-400 to 75g acetone diluent, and use ultrasonic emulsification and high-speed shear to make the dioxide Silicon nanoparticles, polyetheramine D-400 and hydrophobically modified E-42 epoxy resin are mixed uniformly to obtain resin slurry I;

Add 5g of hydrophobically modified E-42 epoxy resin and 2g of polyetheramine D-400 to 5g of acetone diluent, stir and mix uniformly to obtain resin slurry II;

(2) Coating the resin slurry II on the substrate with a coating surface density of 0.008g/cm ² and curing it at 90°C for 20 minutes;

At the same time, immerse the silicon carbide fiber membrane in the resin slurry I, and then volatilize to remove the acetone in the resin slurry I in the silicon carbide fiber membrane, and repeat the above-mentioned dipping and volatilization process several times 3 times;

(3) Laying the impregnated silicon carbide fiber membrane on the side of the substrate coated with the resin slurry II, heating and curing: 85°C for 1 hour and 95°C for 1 hour to obtain a mechanically durable super-hydrophobic nano coating.

The surface of the super-hydrophobic nano-coating is uniform nanoparticles with an average water contact angle of 158.2°; after 60 times of sanding with 600 grit sandpaper, the contact angle is 151.5°, and the surface of the nanofiber skeleton, silica nanoparticles and epoxy are exposed The enlarged surface structure of the resin is shown in Figure 4a; after 100 times of sanding with 360 grit sandpaper, the surface water contact angle is 147.3°; after 10 times with 3M tape, the surface water contact angle is 148.6°; after 50 grit impacts After the experiment, the contact angle of the superhydrophobic composite material was 150.2°; Figure 4b is a hydrophobic picture of the superhydrophobic coating obtained in this example after being polished 60 times with 600 mesh sandpaper, indicating that the superhydrophobic nano coating obtained in this example has a strong Hydrophobicity. The above results indicate that the super-hydrophobic nano-coating using silicon carbide nanofiber membrane as the skeleton can maintain super-hydrophobicity under the conditions of friction, adhesion and dynamic impact, indicating that this type of super-hydrophobic nanocomposite has good durability.

Comparative example one

The preparation process of this comparative example is the same as that of Example 1, except that the nanofiber skeleton is not added to the super-hydrophobic coating, and the resin slurry I is directly sprayed on the semi-cured resin slurry II. The resulting coating is ordinary super Hydrophobic coating.

The surface morphology of the obtained ordinary superhydrophobic coating is similar to that of Fig. 1a, and the surface is uniformly distributed nanoparticles. But after the tape was peeled off for 5 times, the superhydrophobic coating on the surface fell off and the water contact angle dropped to 110.8°. The morphology of the super-hydrophobic coating after stripping is shown in Figure 5a. It contains only a small amount of nano-particles, and no micro-nano structure is constructed, resulting in the loss of super-hydrophobic performance. This indicates that the nanofiber felt has an effect on resin slurry I and resin slurry II The connection plays an important role in intuitiveness, not only can enhance the role of the resin paste I, but also can play an over-connection role. The two co-authors enhance the mechanical durability of the superhydrophobic coating. In addition, it can be seen from Fig. 5b that the ordinary superhydrophobic coating obtained in this comparative example has poor hydrophobic performance after being stripped.

Comparative example two

The preparation process of this comparative example is the same as that of the third embodiment, with the only difference being: in step (2), the coating surface density of the resin slurry II is 0.016 g/cm ² .

The internal optical photo of the obtained hydrophobic coating is shown in Figure 6a. Because the surface density of the underlying resin is too large, the fiber coating is completely saturated by the underlying resin. The surface structure and morphology are shown in Figure 6b. The surface micro-nano structure is lost. The water contact angle is only 108°, indicating that the coating surface density of resin slurry II has a greater impact on the superhydrophobic properties of the coating and must be controlled within a reasonable range.

The above descriptions are only the preferred embodiments of the present invention, and do not limit the scope of the present invention. Under the inventive concept of the present invention, equivalent structural transformations made by using the contents of the description and drawings of the present invention, or direct/indirect use Other related technical fields are included in the scope of patent protection of the present invention.

Claims

A mechanically durable super-hydrophobic nano-coating, characterized in that the nano-coating uses a nanofiber membrane as a skeleton reinforcement phase and a resin slurry as a matrix phase;

The resin slurry includes resin slurry I and resin slurry II; the resin slurry I is a mixture of hydrophobically modified epoxy resin, nanoparticles, curing agent and diluent; the resin slurry II is a hydrophobic modified Mixture of epoxy resin, curing agent and diluent;

The nanofiber membrane is one of polyvinylidene fluoride fiber membrane, polyacrylonitrile fiber membrane, polystyrene fiber membrane, silicon oxycarbon fiber membrane, silicon carbide fiber membrane, alumina fiber membrane and zirconia fiber membrane.
The mechanically durable superhydrophobic nano coating according to claim 1, wherein the average thickness of the nanofiber membrane is 10-30 μm, and the average fiber diameter is 200-600 nm.
The mechanically durable superhydrophobic nano-coating according to claim 2, wherein the average thickness of the nanofiber membrane is 10-20 μm, and the average fiber diameter is 200-500 nm.
The method for preparing a mechanically durable superhydrophobic nano-coating according to any one of claims 1 to 3, characterized in that it comprises the following steps:

(1) Add the mixture of hydrophobically modified epoxy resin, nanoparticles and curing agent to the diluent, and use ultrasonic emulsification and high-speed shear to make the nanoparticles, curing agent and hydrophobically modified epoxy resin uniformly mixed to obtain resin slurry料Ⅰ;

Add the hydrophobically modified epoxy resin and curing agent to the diluent, stir and mix uniformly to obtain resin slurry II;

(2) Coating the resin slurry II on the substrate and curing it at 80°C for 10-40 minutes;

At the same time, immerse the nanofiber membrane in the resin slurry I, and then volatilize to remove the diluent in the resin slurry I in the nanofiber membrane, and repeat the above dipping and volatilization process several times;

(3) Laying the impregnated nanofiber membrane on the side of the substrate coated with the resin slurry II, and heating and curing to obtain a mechanically durable super-hydrophobic nano coating.
The method for preparing a mechanically durable superhydrophobic nano-coating according to claim 4, wherein, in the step (1), the hydrophobically modified epoxy resin is hydrophobically modified E-51 epoxy resin , E-44 epoxy resin and E-42 epoxy resin; the nanoparticles are one of silica nanoparticles, titanium dioxide nanoparticles and aluminum oxide nanoparticles; the curing agent is At least one of diethylenetriamine, triethylenetetramine, diaminodiphenylmethane, polyetheramine D-230 and polyetheramine D-400; the diluent is ethyl acetate, ethanol, N,N- At least one of dimethylformamide, dimethyl sulfoxide, cyclohexane, and acetone.
The method for preparing a mechanically durable superhydrophobic nano-coating according to claim 5, wherein, in the step (1), in the resin slurry I, the hydrophobically modified epoxy resin and the nano-coating The mass ratio of the particles is (1.5-3):1; the mass ratio of the diluent to the total mass of the hydrophobically modified epoxy resin, the nanoparticles, and the curing agent is (3-5):1.
The method for preparing a mechanically durable superhydrophobic nano-coating according to claim 4, wherein, in the step (1), in the resin slurry II, the diluent and the hydrophobically modified epoxy The mass ratio of the total mass of resin and curing agent is (0.5～1.5):1.
The method for preparing a mechanically durable super-hydrophobic nano-coating according to any one of claims 4-7, wherein the average particle diameter of the nano-particles is 20-50 nm.
The method for preparing a mechanically durable super-hydrophobic nano-coating according to claim 7, wherein in the step (2), the coating amount of the resin slurry II on the substrate is 0.003 ~0.014g/cm 2 .
The method for preparing a mechanically durable super-hydrophobic nano-coating according to claim 9, characterized in that, in the step (2), the coating amount of the resin slurry II on the substrate is 0.005 ～0.012g/cm 2 .
The method for preparing a mechanically durable superhydrophobic nano-coating according to claim 4, characterized in that, in the step (2), the immersion time is 3 to 5 minutes, and the temperature is 20 to 30°C; The volatilization is natural volatilization at room temperature; the number of repeated impregnation and volatilization processes is 3-8 times.
The method for preparing a mechanically durable super-hydrophobic nano-coating according to claim 4, wherein, in the step (3), the heating and curing procedure is:

The first stage is 70～85℃, 1～2h;

The second stage is 90～100℃, 1～2h.