CN114806232A - A kind of multi-scale antifouling coating and preparation method and application thereof - Google Patents

Abstract

The invention discloses a multi-scale antifouling coating and a preparation method and application thereof. The invention adopts multi-step reaction to prepare multi-scale silicon dioxide to construct micro-nano structure. The coating prepared by the invention has a lotus leaf-like structure similar to "lotus leaf effect". The preparation method of the invention has the characteristics of simple process, low cost, wide applicability and the like, and is suitable for industrial production.

Description

A kind of multi-scale antifouling coating and preparation method and application thereof

technical field

The invention mainly relates to the related technical field of antifouling coatings, and specifically designs a preparation method for constructing multi-scale antifouling coatings.

Background technique

Lotus leaf is the most typical antifouling self-cleaning material in nature. The water contact angle on the surface is greater than 160°, and the rolling angle is less than 5°, so that the adhesion between the water droplet and the lotus leaf surface is much smaller than the adhesion force between the water droplet, and the surface is quasi-spherical and easy to roll. Remove surface pollutants to achieve the effect of anti-fouling. This self-cleaning ability of lotus leaves is called "lotus leaf effect", and its special performance originates from the micro-nano structure on its surface and the waxy material with low surface energy, in which the micro-nano structure plays a role in reducing the gap between water droplets and the surface. The role of the contact area, and the low surface energy of the lotus leaf surface is generated by the surface waxy layer. This property of the lotus leaf also results in lower surface adhesion and surface friction coefficient.

In recent years, the strategy of constructing superhydrophobic self-cleaning surfaces by inorganic nanoparticles has received great attention, and excellent superhydrophobic self-cleaning effects have been obtained. However, these micro-nano-structured materials have poor film-forming properties, weak adhesion to substrates, and poor mechanical durability, and can easily lose their antifouling function, which seriously restricts their applications.

SUMMARY OF THE INVENTION

The technical scheme of the present invention is as follows:

A method for preparing a micro-nano structure, comprising the steps of:

(1) the solution of the first silicon-based material is quickly added to the alkaline solution, and the dispersion liquid containing the silica seeds is obtained after the reaction;

(2) adding halide to the dispersion liquid containing silica seeds obtained in step (1), and adjusting the pH to be alkaline; slowly adding the solution of the second silicon-based material to carry out a reaction, and then adding the third silicon-based material Carry out secondary reaction to obtain the dispersion liquid of silicon dioxide;

(3) adding silane to the dispersion liquid of silica prepared in step (2) to carry out modification reaction to obtain the dispersion liquid of modified silica;

(4) after mixing the organosilicon modified epoxy resin with the curing agent, it is coated on the surface of the base material to obtain an adhesive layer, and the dispersion of the modified silica obtained in step (3) is sprayed onto the surface of the adhesive layer, After curing, the micro-nano structure is obtained.

According to an embodiment of the present invention, in step (1), the solution of the first silicon-based material includes a first silicon-based material and a dispersion medium.

Preferably, in the first silicon-based material solution, the concentration of the first silicon-based material is 0.01-0.2 g/mL.

According to an embodiment of the present invention, in step (1), the alkaline solution includes a base, deionized water and a dispersion medium.

Preferably, in the alkaline solution, the concentration of the base is 0.01-0.2 g/mL, for example, 0.06 g/mL.

Preferably, in the alkaline solution, the volume ratio of deionized water and dispersion medium is (0.5-2):1, for example, 1:1.

According to an embodiment of the present invention, in step (1), the mass ratio of the first silicon-based material and the base is (1-3):1, for example, 3:2.

According to an embodiment of the present invention, the dispersion medium is selected from at least one of methanol, ethanol, and isopropanol.

According to an embodiment of the present invention, in step (1), the reaction includes: reacting at a constant temperature of 20-40° C. for 2-6 hours, for example, reacting at a constant temperature of 35° C. for 5 hours.

According to an embodiment of the present invention, the base is selected from at least one of ammonia, sodium hydroxide, and potassium hydroxide.

According to an embodiment of the present invention, the silica seeds have a morphology substantially as shown in FIG. 1 . Preferably, the size of the silica seeds is uniform, for example, 10-100 nm, and for example, 74 nm.

According to an embodiment of the present invention, in step (2), the halide is selected from potassium chloride, sodium chloride, and calcium chloride.

According to an embodiment of the present invention, in step (2), the mass-to-volume ratio (mg:mL) of the halide to the dispersion containing the silica seeds is (0.1-10) mg:60mL, such as 1.5mg: 60mL.

According to an embodiment of the present invention, adjusting the pH to be alkaline in step (2) means that the pH value is 8-10, for example, 8.5. The present invention does not specifically limit the method for adjusting the pH in step (2), and a method known in the art can be selected, as long as the pH value can be adjusted to the stated value.

According to an embodiment of the present invention, in step (2), the solution of the second silicon-based material includes the second silicon-based material and a dispersion medium, and the dispersion medium has the meaning as described above.

Preferably, in the solution of the second silicon-based material, the concentration of the second silicon-based material is 0.05-0.3 g/mL, for example, 0.094 g/mL.

According to an embodiment of the present invention, in step (2), the slow addition means that the addition rate of the solution of the second silicon-based material is 20-50 mL/h, for example, 30 mL/h.

According to an embodiment of the present invention, in step (2), the mass ratio of the second silicon-based material and the third silicon-based material is (0.5-3):1, for example, 1:1.

According to an embodiment of the present invention, the first silicon-based material, the second silicon-based material and the third silicon-based material may be the same or different, and are independently selected from tetraethyl orthosilicate and silicon tetrachloride.

Preferably, the first silicon-based material, the second silicon-based material and the third silicon-based material are the same, for example, selected from tetraethyl orthosilicate.

According to an embodiment of the present invention, the mass ratio of the first silicon-based material and the second silicon-based material is (0.2-1):1.

According to an embodiment of the present invention, in step (2), in the solution of silicon dioxide, the silicon dioxide has a shape substantially as shown in FIG. 2 . Preferably, the silica has a multi-scale particle size, eg, 50-2000 nm. Further, the silica includes small-sized microspheres (eg, a particle size of 50-250 nm) and large-sized microspheres (eg, a particle size of 250-2000 nm, eg, 250-500 nm).

The inventors found that through the above-mentioned primary reaction and secondary reaction, two kinds of silica with different scales can be obtained at the same time.

According to an embodiment of the present invention, in step (3), the silane is selected from at least one of dimethyldichlorosilane, hexamethyldisilazane, dimethylsilane, and octamethylcyclotetrasiloxane kind.

According to an embodiment of the present invention, in step (3), a diluent may also be added. Preferably, the diluent is for example selected from deionized water. Further, in step (3), the silane is added first, and then the diluent is added. The hydrolysis rate of the silane can be controlled after adding the diluent.

According to an embodiment of the present invention, in step (3), the conditions of the modification reaction include: a constant temperature reaction at 50-90° C. for 0.1-10 h, for example, a constant temperature reaction at 70° C. for 1 h.

According to an embodiment of the present invention, in step (3), the morphology of the modified silica is substantially the same as that of the silica, which has a multi-scale particle size.

According to an embodiment of the present invention, in step (4), the epoxy equivalent of the silicone-modified epoxy resin is preferably 180-220, for example, 185-205.

Preferably, the epoxy resin is selected from an epoxy value of 0.02-0.2 mol/100g. In the present invention, the epoxy value refers to the amount of epoxy groups contained in 100 g of epoxy resin.

According to an embodiment of the present invention, in step (4), the curing agent is selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diaminodicyclohexylmethane, diaminodiphenylmethane , Polyamide.

According to an embodiment of the present invention, in step (4), the mass ratio of the silicone-modified epoxy resin and the curing agent is (5-30):1, for example, 10:1.

According to an embodiment of the present invention, in step (4), the timing of spraying the dispersion of the modified silica is preferably when the adhesive layer is in a semi-cured state. Preferably, the semi-cured state in the present invention means that the resin in the adhesive layer is partially cross-linked, is solid at room temperature, and is in a molten state when heated above 60°C.

According to an embodiment of the present invention, in step (4), the mass content of the modified silica dispersion liquid is 1-30 wt %, for example, 10 wt %.

According to the embodiment of the present invention, the present invention does not specifically limit the amount of the modified silica dispersion sprayed on the surface of the adhesive layer in step (4), as long as the static contact angle of the surface of the coating can be obtained greater than 150°, and the roll angle is less than 5°. Exemplarily, the spraying dosage of the modified silica dispersion is 2 mL/cm ² .

According to an embodiment of the present invention, in step (4), the substrate may be selected from substrates known in the art, for example, selected from glass, cloth, metal, and plastic.

According to an embodiment of the present invention, in steps (1)-(4), the reactions can be carried out under stirring. Preferably, the stirring is not specifically limited in the present invention, and a stirring method known in the art can be used as long as the reaction can be achieved.

The present invention also provides a micro-nano structure obtained by the above preparation method, wherein the micro-nano structure comprises an adhesion layer and modified silica distributed on the surface of the adhesion layer.

According to an embodiment of the present invention, the particle size of the modified silica is selected from 50-2000 nm.

Preferably, the modified silica is prepared by using silane to modify the surface of the silica.

Further, the silica and silane have the meanings as described above.

According to an embodiment of the present invention, the modified silica includes large silica microspheres and small silica microspheres. Preferably, small silica microspheres are distributed around each of the large silica microspheres, preferably forming a nanoscale periodic concavo-convex structure.

Further, the average particle size of the large silica microspheres is 250-2000 nm, for example, 250-500 nm, and for example, 389 nm. Further, the particle size of the silica microspheres is 50-250 nm, for example, 116 nm.

According to an embodiment of the present invention, the water static contact angle of the surface of the micro-nano structure is greater than 150°, for example, 158.5°.

According to an embodiment of the present invention, the surface roll angle of the micro-nano structure is less than 5°.

The present invention also provides the application of the micro-nano structure in the field of antifouling, such as for antifouling coating.

The present invention also provides a coating comprising the above-mentioned micro-nano structure and a substrate, wherein the micro-nano structure is located on at least one side of the substrate. The substrate has the meaning as described above.

Preferably, the micro-nano structures are bonded to the substrate through an adhesive layer, the adhesive layer having the meaning as described above.

Beneficial effects of the present invention:

(1) The present invention adopts multi-step reaction to prepare multi-scale silica to construct micro-nano structure.

(2) The present invention selects low surface energy organosilicon-modified epoxy resin as film-forming material, and multi-scale modified silica as functional material, forming a coating with a lotus leaf-like structure having a similar "lotus leaf effect". Floor.

(3) The present invention uses resin as the adhesive layer, which greatly improves the durability of the coating.

(4) The preparation method of the multi-scale coating provided by the present invention has the characteristics of simple process, low cost, wide applicability and the like, and is suitable for industrial production.

Description of drawings

FIG. 1 is a scanning electron microscope image of the silica seeds prepared in Example 1. FIG.

FIG. 2 is a scanning electron microscope image of the multi-scale silica prepared in Example 1. FIG.

3 is an infrared spectrum diagram of the multi-scale silica prepared in Example 1 before and after chemical modification.

FIG. 4 is a contact angle test chart of the multi-scale coating prepared in Example 1. FIG.

FIG. 5 is a contact angle test chart of the multi-scale coating prepared in Example 2. FIG.

FIG. 6 is a contact angle test chart of the monodisperse silica coating prepared in Comparative Example 1. FIG.

FIG. 7 is the contact angle test chart of the unmodified multi-scale coating prepared in Comparative Example 2. FIG.

Detailed ways

The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following examples are only for illustrating and explaining the present invention, and should not be construed as limiting the protection scope of the present invention. All technologies implemented based on the above content of the present invention are covered within the intended protection scope of the present invention.

Unless otherwise stated, the starting materials and reagents used in the following examples are commercially available or can be prepared by known methods.

Example 1

(1) Preparation of silica seeds: 25mL of absolute ethanol, 25mL of deionized water, and 3mL of 28wt% ammonia water (purchased from Aladdin Reagent Co., Ltd.) were mixed to obtain mixed solution A, wherein the role of ammonia was to act as a silicon source for hydrolysis The catalyst; Tetraethyl orthosilicate (purchased from Sinopharm Chemical Reagent Co., Ltd.) was added in 50mL of dehydrated alcohol, and the ethanolic solution of the tetraethylorthosilicate of 0.0841g/mL was prepared, which was denoted as solution B; then , under the state of magnetic stirring, quickly pour the B solution into the A solution at one time, react in a constant temperature oil bath at 35 ° C for 5 hours, and then centrifuge the reaction solution to discard the supernatant to obtain the reaction precipitate. Disperse the precipitate, and centrifuge it again to obtain the precipitate. In this way, the silica seeds are obtained by cyclic washing more than 3 times. The washed silica seeds are uniformly dispersed into 60 mL of ethanol by ultrasonic wave to obtain a silica seed dispersion liquid, which is denoted as solution C.

(2) Preparation of multi-scale silica: 0.0015g KCl, 6mL deionized water and 3mL 28wt% ammonia water (purchased from Aladdin Reagent Co., Ltd.) were added to the silica seed dispersion in step (1) to form a mixed solution. It is solution D, in which the role of ammonia is to act as a catalyst for the hydrolysis of silicon source, and the role of chloride salt is to further increase the silica seeds; 5.64g of tetraethyl orthosilicate is added to 60mL of anhydrous ethanol to prepare orthosilicic acid The ethanolic solution of tetraethyl ester was recorded as solution E; then, solution E was slowly added to solution D within 2 h with a peristaltic pump. Then, solution C and 5.64g of tetraethyl orthosilicate were added in sequence, and the reaction was continued in a constant temperature oil bath at 35°C for 20 hours. After that, the reaction solution was centrifuged and the supernatant was discarded to obtain a reaction precipitate, and then an appropriate amount of anhydrous ethanol was used to disperse the precipitate. , and centrifuged again to obtain the precipitate, and the multi-scale silica was obtained by cyclic washing more than 3 times. The multi-scale silica was dispersed in 100 mL of ethanol to obtain a multi-scale silica dispersion.

(3) Silane-modified multi-scale silica: add 5 mL of dimethyldichlorosilane and 5 g of deionized water to the multi-scale silica dispersion obtained in step (2), and magnetically force it in a constant temperature oil bath at 70°C. Stir and reflux for 1 h. The reaction solution was centrifuged and washed, and then dispersed into ethanol to obtain a modified multi-scale silica dispersion, the mass content of which was 10%.

(4) Silicone modified epoxy resin (purchased from Hehe High-tech Materials (Shanghai) Co., Ltd., model EPSI-3201, epoxy equivalent of 185-205) and polyamide curing agent (651) (purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.) uses simple mechanical stirring to mix evenly, and then coats the surface of the glass substrate to obtain an adhesion layer (the mass ratio of silicone modified epoxy resin and curing agent is 10:1). The substance in the adhesion layer reacts to a semi-cured state, and the modified multi-scale silica dispersion obtained in step (3) is sprayed on the surface of the adhesion layer, the spray distance is kept at 15cm, and the spray amount is 2mL/cm ² . After curing , to obtain a multi-scale antifouling coating.

FIG. 1 is a scanning electron microscope image of the silica seeds prepared in Example 1. FIG. It can be seen from Figure 1 that the particle size of the silica seeds is uniform and has good monodispersity, and the average particle size distribution is about 74 nm.

FIG. 2 is a scanning electron microscope image of the multi-scale silica prepared in Example 1. FIG. It can be seen from Figure 2 that the multi-scale silica includes large silica microspheres with an average particle size of 389 nm, and basically each large silica microsphere is surrounded by silica with a particle size of about 116 nm. Small microspheres, thus forming many nanoscale periodic concave-convex structures. The prepared multi-size silica has different particle sizes and a particle size distribution width of 50-500nm, and there are roughly two particle size distribution peaks, of which 50-250nm accounts for 50%, and 250-500nm accounts for 50%. The expected production of multi-sized silica is achieved.

3 is the Fourier transform infrared spectrum of the multi-scale silica prepared in Example 1 before and after chemical modification. The testing instrument was a Fourier transform infrared spectrometer (NICOLETiS5, Thermo Fisher Scientific, USA). It can be seen from Figure 3 that the characteristic absorption peak corresponding to the Si-OH bond in the modified silica disappears, because the -OH at the end of the silica reacts with -Cl of dimethyldichlorosilane, thereby Substances with low surface energy were grafted on the silica surface, which indicated that the modified silica was successfully prepared.

FIG. 4 is a contact angle test chart of the multi-scale antifouling coating prepared in Example 1. FIG. The test instrument is a contact angle measuring instrument (JC2000D, Shanghai Zhongchen), and the test method is to measure the static contact angle and rolling angle of the above-prepared coating samples at room temperature (23°C), and the tested liquid is deionized. Water, the static contact angle droplet volume test amount is 2 μL, the rolling angle droplet volume test amount is 14 μL, the working voltage is 220V, and the power frequency is 50Hz. It can be seen from FIG. 4 that the static contact angle of the coating prepared in Example 1 is 158.49°, and the rolling angle is 1°. From this, it can be judged that the coating of this example has super water repellency.

Example 2

The preparation method of this embodiment is basically the same as that of embodiment 1, except that the glass substrate in step (4) is replaced with polyester cloth.

As shown in FIG. 5 , the static contact angle of the coating prepared in this example is 158.99° and the rolling angle is 3°.

Comparative Example 1

(1) Preparation of monodisperse silica particles: 25mL of absolute ethanol, 25mL of deionized water, and 3mL of ammonia water were added to a 250mL three-necked flask, and magnetically stirred for 5 minutes to form a mixed solution as solution A); Ethyl ethyl ester was added to 50 mL of absolute ethanol to prepare an ethanol solution of ethyl orthosilicate (defined as solution B); then, under magnetic stirring, quickly pour solution B into solution A at one time, and keep the oil at a constant temperature of 35 °C. The reaction was carried out in a bath for several hours; the sol obtained from the reaction was subjected to centrifugal precipitation, and the precipitate was washed with absolute ethanol and ultrasonically circulated 3 times (to remove unreacted raw materials in the product).

(2) Monodisperse Silica Add the above-synthesized various types of silica into 100 mL of absolute ethanol respectively, stir and ultrasonic to make it disperse uniformly; under stirring state, add 5 mL of dimethyldichlorosilane and 5 g of deionized water in turn , and refluxed with magnetic stirring in a constant temperature oil bath at 70 °C for 1 h. The reaction solution was centrifuged to obtain the filter residue, washed with absolute ethanol for three times by centrifugal ultrasonic cycle, and finally, dried in an oven at 60° C., and ground into powder for later use.

After taking 0.5 g of the powder prepared in step (2) and dispersing it in 49.5 g of ethanol, a coating was prepared with reference to step (4) of Example 1.

As shown in Fig. 6, the static contact angle of the coating of this comparative example is 125.63°, and the rolling angle is greater than 10°.

Comparative Example 2

(1) Synthesis of monodisperse silica: add 25 mL of absolute ethanol, 25 mL of deionized water, and 3 mL of ammonia into a 250 mL three-necked flask, stir magnetically for 5 minutes to form a mixed solution, which is defined as solution A; add 4.5 mL of orthosilicic acid Tetraethyl ester was added to 50 mL of absolute ethanol to prepare an ethanol solution of ethyl orthosilicate, which was defined as solution B; then, under magnetic stirring, quickly pour solution B into solution A at one time, and keep the oil at a constant temperature of 35 °C. The reaction was carried out in a bath for several hours; the sol obtained from the reaction was subjected to centrifugal precipitation, and the precipitate was washed with absolute ethanol and ultrasonically circulated 3 times (to remove unreacted raw materials in the product).

(2) Synthesis of multi-scale silica: Weigh 0.7 g of the silica prepared in the above step (1) and add it to 30 mL of absolute ethanol, stir and ultrasonically mix to form a seed solution, which is defined as solution C. In a 250mL three-necked flask, add 0.0015g KCl, 38mL absolute ethanol, 6mL deionized water, and 3mL ammonia water to form a mixed solution, which is defined as solution D; add 5.64g tetraethyl orthosilicate to 58mL absolute ethanol to prepare ortho-silicon Ethanol solution of tetraethyl acid, defined as solution E; then, solution E was slowly added to solution D within 2 h with a peristaltic pump. Subsequently, solution C and 5.64 g of tetraethyl orthosilicate were added in sequence, and the reaction was continued for 20 h under a constant temperature oil bath at 35°C. The reaction solution was centrifuged to take the filter residue, washed with absolute ethanol for 3 ultrasonic cycles, and finally, dried in an oven at 60°C, and ground into powder for later use.

Disperse 0.5 g of the powder prepared in step (2) in 49.5 g of ethanol without chemical modification of dimethyldichlorosilane, and prepare a coating by referring to step (4) of Example 1.

As shown in FIG. 7 , the static contact angle of the coating of this comparative example is 14.39°, and the rolling angle is greater than 10°.

Exemplary embodiments of the present invention have been described above. However, the protection scope of the present application is not limited to the above-mentioned embodiments. Any modifications, equivalent replacements, improvements, etc. made by those skilled in the art within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims (10)

1. a preparation method of micro-nano structure, is characterized in that, comprises the steps: (1) the solution of the first silicon-based material is quickly added to the alkaline solution, and the dispersion liquid containing the silica seeds is obtained after the reaction; (2) adding halide to the dispersion liquid containing silica seeds obtained in step (1), and adjusting the pH to be alkaline; slowly adding the solution of the second silicon-based material to carry out a reaction, and then adding the third silicon-based material Carry out secondary reaction to obtain the dispersion liquid of silicon dioxide; (3) adding silane to the dispersion liquid of silica prepared in step (2) to carry out modification reaction to obtain the dispersion liquid of modified silica; (4) after mixing the organosilicon modified epoxy resin with the curing agent, it is coated on the surface of the base material to obtain an adhesive layer, and the dispersion of the modified silica obtained in step (3) is sprayed onto the surface of the adhesive layer, After curing, the micro-nano structure is obtained. 2 . The preparation method according to claim 1 , wherein, in step (1), the solution of the first silicon-based material comprises a first silicon-based material and a dispersion medium. 3 . Preferably, in the first silicon-based material solution, the concentration of the first silicon-based material is 0.01-0.2 g/mL. Preferably, in step (1), the alkaline solution includes alkali, deionized water and a dispersion medium. Preferably, in the alkaline solution, the concentration of the alkali is 0.01-0.2 g/mL. Preferably, in the alkaline solution, the volume ratio of deionized water and dispersion medium is (0.5-2):1. Preferably, in step (1), the mass ratio of the first silicon-based material and the alkali is (1-3):1. Preferably, the dispersion medium is selected from at least one of methanol, ethanol and isopropanol. Preferably, in step (1), the reaction includes: reacting at a constant temperature of 20-40° C. for 2-6 hours. Preferably, the base is selected from at least one of ammonia, sodium hydroxide and potassium hydroxide. Preferably, the silica seeds have a morphology substantially as shown in FIG. 1 . Preferably, the silica seeds are uniform in size. 3. preparation method according to claim 1 and 2 is characterized in that, in step (2), described halide is selected from potassium chloride, sodium chloride, calcium chloride. Preferably, in step (2), the mass-volume ratio of the halide to the dispersion liquid containing the silica seeds is (0.1-10) mg:60 mL. Preferably, adjusting the pH to be alkaline in step (2) means that the pH is 8-10. Preferably, in step (2), the solution of the second silicon-based material includes the second silicon-based material and the dispersion medium. Preferably, in the solution of the second silicon-based material, the concentration of the second silicon-based material is 0.05-0.3 g/mL. Preferably, in step (2), the slow addition means that the addition rate of the solution of the second silicon-based material is 20-50 mL/h. Preferably, in step (2), the mass ratio of the second silicon-based material to the third silicon-based material is (0.5-3):1. 4. The preparation method according to any one of claims 1-3, wherein the first silicon-based material, the second silicon-based material and the third silicon-based material can be the same or different, and are selected independently from each other. From tetraethyl orthosilicate, silicon tetrachloride. Preferably, the first silicon-based material, the second silicon-based material and the third silicon-based material are the same. Preferably, the mass ratio of the first silicon-based material and the second silicon-based material is (0.2-1):1. Preferably, in step (2), in the solution of silicon dioxide, the silicon dioxide has a shape substantially as shown in FIG. 2 . Preferably, the particle size of the silica is 50-2000 nm. Further, the silica includes small-sized microspheres and large-sized microspheres. Preferably, the particle size of the small-sized microspheres is 50-250 nm. Preferably, the particle size of the large-sized microspheres is 250-2000 nm. 5. The preparation method according to any one of claims 1-4, wherein in step (3), the silane is selected from dimethyldichlorosilane, hexamethyldisilazane, dimethyl At least one of silane and octamethylcyclotetrasiloxane. Preferably, in step (3), a diluent can also be added. Preferably, in step (3), the conditions of the modification reaction include: a constant temperature reaction at 50-90° C. for 0.1-10 h. Preferably, in step (3), the morphology of the modified silica is substantially the same as that of the silica, and it has a multi-scale particle size. 6 . The preparation method according to claim 1 , wherein, preferably, in step (4), the epoxy equivalent of the silicone-modified epoxy resin is preferably 180-220. 7 . Preferably, the silicone-modified epoxy resin is selected from the group whose epoxy value is 0.02-0.2 mol/100g. Preferably, in step (4), the curing agent is selected from ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, diaminodicyclohexylmethane, diaminodiphenylmethane, and polyamide. Preferably, in step (4), the mass ratio of the silicone-modified epoxy resin to the curing agent is (5-30):1. Preferably, in step (4), the mass content of the modified silica dispersion liquid is 1-30 wt %. 7. A micro-nano structure obtained by the preparation method according to any one of claims 1-6, wherein the micro-nano structure comprises an adhesive layer and a modified two-layer structure distributed on the surface of the adhesive layer. Silicon oxide. Preferably, the particle size of the modified silica is selected from 50-2000 nm. Preferably, the modified silica is prepared by using the silane to modify the surface of the silica. 8 . The micro-nano structure according to claim 7 , wherein the modified silica comprises large silica microspheres and small silica microspheres. 9 . Preferably, small silica microspheres are distributed around each of the large silica microspheres, preferably forming a nano-scale periodic concavo-convex structure. Further, the average particle size of the large silica microspheres is 250-2000 nm. Further, the particle size of the silica microspheres is 50-250 nm. Preferably, the static contact angle of the surface of the micro-nano structure is greater than 150°. Preferably, the surface roll angle of the micro-nano structure is less than 5°. 9. The application of the micro-nano structure of claim 7 or 8 in the field of antifouling, such as for antifouling coating. 10. A coating, characterized in that the coating comprises the micro-nano structure according to claim 7 or 8 and a substrate, and the micro-nano structure is located on at least one side of the substrate. Preferably, the micro-nano structures are bonded to the substrate through an adhesive layer.

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