Preparation method and application of snowman-shaped 3-APF (at) mSiO2Janus particle

Abstract

The invention relates to a preparation method of snowman-shaped 3-APF (at) mSiO2Janus particles and application of the snowman-shaped 3-APF (at) mSiO2 Janus particles. According to the method, tetraethyl silicate is adopted as an oil drop template and a precursor of SiO2 at the same time, and Janus particles with rich mesopores and two end compositions of 3-APF and SiO2 are obtained under the combined action of positive and negative charges and interfacial tension; the particles serve as a carrier of a color developing agent and a compatibilizer of linseed oil and WPU, and the intelligent anti-corrosion coating with corrosion self-reporting and damage self-repairing functions is obtained. The method breaks through the limitation that an existing emulsion template technology can only be used for preparing single-component Janus particles, avoids a later complex template removal step, and has the advantages of being simple in step, suitable for large-scale preparation of the Janus particles and the like.

Description

Technical Field

[0001] The present invention belongs to the field of organic-inorganic hybrid nanomaterials, and particularly relates to a preparation method and application of snowman-shaped 3-APF@mSiO2 Janus particles. Background Art

[0002] In recent years, the emulsion template-induced strategy has attracted extensive research interest due to its advantages such as easy template removal, simple synthesis route, accessible raw materials, and large-scale production. In this strategy, the oil-water emulsion not only serves as the interface for the assembly of primary particles to regulate the particle morphology, but also provides a stable reaction space for the growth of particles, offering unparalleled opportunities for the synthesis of Janus particles with various morphologies and functions. Li et al. prepared mushroom-shaped, wheel-shaped, and acorn-shaped poly(m-phenylenediamine) Janus particles by a one-pot emulsion template strategy using a mixture of mesitylene / water as the emulsion template and m-phenylenediamine as the reaction monomer (Adv. Mater. 2021, 33, 2102930). Similarly, Liu et al. prepared nested, basin-shaped, dendritic, and mountain-shaped 3-aminophenol formaldehyde resin Janus particles by this strategy using a mixture of cyclohexane / water and a mixture of cyclohexane and n-hexanol / water as the emulsion templates and 3-aminophenol and formaldehyde as the reaction monomers, respectively (Adv. Mater. 2023, 35, 2210963). Currently, the synthesis of Janus particles using this method always requires the introduction of additional oil droplet templates, which inevitably leads to waste of raw materials and a cumbersome post-treatment process. Moreover, since the simultaneous introduction of multiple reaction components increases the complexity of the emulsion system, the Janus particles prepared by this method are limited to a single component. Summary of the Invention

[0003] The object of the present invention is to address the limitations in the current technology and provide a preparation method of snowman-shaped 3-APF@mSiO2 Janus particles. This method uses the emulsion self-template method to "one-pot" prepare snowman-shaped 3-APF@mSiO2 Janus particles with adjustable particle size and end sizes. By using tetraethyl orthosilicate as both the oil droplet template and the precursor of SiO2, Janus particles with rich mesopores and 3-APF and SiO2 at both ends are obtained under the combined action of positive and negative charges and interfacial tension; using these particles as the carrier of the chromogenic agent and the compatibilizer of linseed oil and WPU, an intelligent anti-corrosion coating with both corrosion self-reporting and damage self-healing functions is obtained. The present invention breaks the limitation that the existing emulsion template technology can only be used to prepare single-component Janus particles and avoids the complex template removal steps in the later stage, having advantages such as simple steps and being suitable for large-scale preparation of Janus particles.

[0004] To achieve the above-mentioned invention purposes, the present invention provides the following technical solutions:

[0005] A preparation method of snowman-shaped 3-APF@mSiO2 Janus particles, and the preparation method is as follows:

[0006] The material composition and ratio are as follows:

[0007]

[0008]

[0009] Step (1): According to the above raw material ratio, distilled water, 3-aminophenol, absolute ethanol, CTAB, and ammonia water are ultrasonically mixed to obtain a homogeneous solution.

[0010] Step (2): TEOS is dropped into the above solution under stirring; after the dropping is completed, a formaldehyde solution is added thereto, and the reaction continues for 20 to 30 h. After purification treatment, snowman-shaped 3-APF@mSiO2 Janus particles are obtained;

[0011] The mass percentage concentration of the formaldehyde solution is 30 to 40%;

[0012] The mass percentage concentration of the ammonia water is 20 to 30%.

[0013] Preferably, in step (2), the stirring rate is 150 to 500 rpm, and the reaction temperature is 25 to 65 °C.

[0014] Preferably, in step (2), the dropping time of TEOS is 10 to 80 min.

[0015] The particle size of the prepared snowman-shaped 3-APF@mSiO2 Janus particles is 90 to 500 nm.

[0016] The size of the mSiO2 end of the prepared snowman-shaped 3-APF@mSiO2 Janus particles is 40 to 130 nm, and the mesopore size is 1 to 5 nm.

[0017] The size of the 3-APF end of the prepared snowman-shaped 3-APF@mSiO2 Janus particles is 40 to 300 nm.

[0018] The application of the snowman-shaped 3-APF@mSiO2 Janus particles prepared by the method is used for preparing an intelligent anti-corrosion coating with corrosion self-reporting and self-healing functions.

[0019] Specifically, it includes the following steps:

[0020] Step (1): Dissolve phen-NH2 in absolute ethanol to obtain a phen-NH2 ethanol solution with a concentration of 25 - 90 mg / L;

[0021] Step (2): Using the impregnation method, drop the ethanol solution of phen-NH2 obtained in step (1) onto the snowman-shaped 3-APF@mSiO2 Janus particle powder, and after drying, obtain snowman-shaped 3-APF@mSiO2 Janus particles loaded with phen-NH2;

[0022] Among them, 2.5 mL of the ethanol solution of phen-NH2 is dropped per 0.1 - 1 g of the snowman-shaped 3-APF@mSiO2 Janus particle powder;

[0023] Step (3): Ultrasonically disperse the snowman-shaped 3-APF@mSiO2 Janus particles loaded with phen-NH2 and distilled water to obtain a particle dispersion;

[0024] Among them, 0.010 - 0.025 g of the snowman-shaped 3-APF@mSiO2 Janus particles loaded with phen-NH2 is added per 2 - 6 mL of distilled water;

[0025] Step (4): Add linseed oil to the above dispersion, and after ultrasonically dispersing evenly, obtain an O / W type Pickering emulsion with an oil droplet diameter of 45 μm - 150 μm;

[0026] Among them, 2 - 6 mL of linseed oil is added per 2 - 6 mL of the dispersion;

[0027] Step (5): Stir the obtained Pickering emulsion and the aqueous polyurethane emulsion evenly and then drop-coat them on the substrate to obtain an intelligent anti-corrosion coating with a thickness of 100 - 800 μm, which has both corrosion self-reporting and self-healing properties;

[0028] Among them, the mass ratio of the Pickering emulsion to the aqueous polyurethane is 1:(1 - 2).

[0029] The substrate is tinplate and glass. The concentration of the aqueous polyurethane emulsion is 40 - 60 wt%.

[0030] Compared with the existing technology, the beneficial effects of the present invention are:

[0031] (1) A emulsion self-template strategy was developed for the "one-pot" preparation of snowman-shaped 3-APF@mSiO2 Janus particles with well-defined two ends, adjustable sizes and abundant mesopores. This preparation method breaks the limitation of the existing emulsion template method which is only used for the preparation of single-component Janus particles, and prepares organic / inorganic hybrid Janus particles, with the advantages of simple process, no raw material waste, low cost and high yield, being suitable for large-scale production and application.

[0032] (2) By fully utilizing the characteristics of the prepared particles: the mSiO2 end has abundant mesopores (as the carrier of the chromogenic agent phen-NH2); the amphiphilicity of the particles (as the compatibilizer of linseed oil and WPU), two functional materials were successfully and uniformly introduced into the WPU coating, and an intelligent anti-corrosion coating with both self-healing and corrosion self-reporting functions was prepared. It opens up a new direction for the application of Janus particles in anti-corrosion coatings.

[0033] (3) The prepared coating has good anti-corrosion performance, and its low-frequency impedance modulus is as high as 3.89×10 8 ohm·cm 2 ; good room-temperature self-healing ability. Different from the existing coatings, the anti-corrosion performance of this coating after repair is significantly improved compared with the original coating; sensitive corrosion self-reporting performance. Once the coating is corroded, it will immediately show red to report the corrosion situation. Description of the Drawings

[0034] Figure 1 SEM photograph of the snowman-shaped 3-APF@mSiO2 Janus particles prepared in Example 3.

[0035] Figure 2 TEM photograph of the snowman-shaped 3-APF@mSiO2 Janus particles prepared in Example 3.

[0036] Figure 3 Particle size distribution histogram of the snowman-shaped 3-APF@mSiO2 Janus particles prepared in Example 3.

[0037] Figure 4 Scanning electron microscope photograph of the spherical particles prepared in Comparative Example 1

[0038] Figure 5 Optical microscope photograph of the anti-corrosion coating with both self-healing and corrosion self-reporting functions prepared in Example 8.

[0039] Figure 6 Scanning electron microscope photograph of the cross-section of the anti-corrosion coating with both self-healing and corrosion self-reporting functions prepared in Example 8.

[0040] Figure 7SEM image of the distribution of 3-APF@mSiO2 Janus particles in the anti-corrosion coating with both self-healing and corrosion self-reporting functions prepared in Example 8.

[0041] Figure 8 Bode plot of the anti-corrosion coating with both self-healing and corrosion self-reporting functions prepared in Example 8.

[0042] Figure 9 SEM image of the anti-corrosion coating with both self-healing and corrosion self-reporting functions prepared in Example 8 after damage repair.

[0043] Figure 10 Photo of the anti-corrosion coating with both self-healing and corrosion self-reporting functions prepared in Example 8 after being damaged and placed in 3.5 wt% NaCl aqueous solution for 72 h. Detailed implementation manners

[0044] The preparation method and application of a snowman-shaped 3-APF@mSiO2 Janus particle according to the present invention are described below through specific examples.

[0045] Example 1.

[0046] (1) Weigh 45 g of distilled water, 0.5 g of 3-aminophenol, 20 mL of absolute ethanol, 0.5 g of CTAB, and 0.18 g of ammonia water (28 wt%). After ultrasonic dispersion, transfer them into a three-necked flask.

[0047] (2) Under the conditions of a stirring rate of 300 rpm and a temperature of 35 °C, use a syringe pump to dropwise add 1.68 g of TEOS to it, and set the dropping time to 10 min. After the dropping is completed, immediately add 0.73 g of formaldehyde solution (37 wt%) to it, and continue the reaction for 22 h. After purification, snowman-shaped 3-APF@mSiO2 Janus particles are obtained.

[0048] Example 2.

[0049] (1) Weigh 45 g of distilled water, 0.5 g of 3-aminophenol, 20 mL of absolute ethanol, 0.5 g of CTAB, and 0.18 g of ammonia water. After ultrasonic dispersion, transfer them into a three-necked flask.

[0050] (2) Under the conditions of a stirring rate of 300 rpm and a temperature of 35 °C, use a syringe pump to dropwise add 1.68 g of TEOS to it, and set the dropping time to 20 min. After the dropping is completed, add 0.73 g of formaldehyde solution to it, and continue the reaction for 22 h. After purification, snowman-shaped 3-APF@mSiO2 Janus particles are obtained.

[0051] Example 3.

[0052] (1) Weigh 45 g of distilled water, 0.5 g of 3-aminophenol, 20 mL of anhydrous ethanol, 0.5 g of CTAB, and 0.18 g of aqueous ammonia, disperse them uniformly by ultrasonication, and transfer them into a three-necked flask.

[0053] (2) Under the conditions of stirring rate of 300 rpm and temperature of 35°C, 1.68 g of TEOS was added dropwise using a syringe pump for 30 min. After the addition, 0.73 g of formaldehyde solution was added and the reaction was continued for 22 h. After purification, snowman-shaped 3-APF@mSiO2 Janus particles were obtained.

[0054] Test method:

[0055] A. Characterization of the surface morphology of particles: 1 mg of snowman-shaped 3-APF@mSiO2 Janus particles was added to 5 mL of distilled water and dispersed evenly by ultrasonication at room temperature. A drop of dispersion was taken with a disposable sterile syringe and added to the surface of the conductive silicon wafer. After drying, the surface morphology of the particles was characterized using a Nano 450 scanning electron microscope from FEI, USA.

[0056] B. Characterization of the internal morphology of particles: 1 mg of snowman-shaped 3-APF@mSiO2 Janus particles were added to 5 mL of distilled water and dispersed evenly by ultrasonication at room temperature. A drop of dispersion was taken with a disposable sterile syringe and added to the surface of the copper mesh with carbon film. After drying, the internal morphology of the particles was observed using a JEM-2100F transmission electron microscope from JEOL, Japan.

[0057] C. Particle size test: Add 1 mg of snowman-shaped 3-APF@mSiO2 Janus particles to 50 mL of distilled water and disperse them evenly under ultrasonic conditions at room temperature. Pour a certain amount of the dilution into a cuvette and test it using a Zeta-SizerNano 90 nanometer laser particle size analyzer from Malvern, UK.

[0058] Example 4.

[0059] (1) Weigh 45 g of distilled water, 0.5 g of 3-aminophenol, 20 mL of anhydrous ethanol, 0.5 g of CTAB, and 0.18 g of aqueous ammonia, disperse them uniformly by ultrasonication, and transfer them into a three-necked flask.

[0060] (2) Under the conditions of stirring rate of 300 rpm and temperature of 35°C, 1.68 g of TEOS was added at one time, and after reacting for 30 min, 0.73 g of formaldehyde solution was added and the reaction was continued for 22 h. After purification, snowman-shaped 3-APF@mSiO2 Janus particles were obtained.

[0061] Example 5.

[0062] (1) Weigh 45 g of distilled water, 0.5 g of 3-aminophenol, 20 mL of absolute ethanol, 0.5 g of CTAB, and 0.18 g of ammonia water. After ultrasonic dispersion until homogeneous, transfer it into a three-necked flask.

[0063] (2) Under the conditions of a stirring rate of 300 rpm and a temperature of 35 °C, add 1.68 g of TEOS to the system all at once. After reacting for 30 min, add 0.73 g of formaldehyde solution thereto and continue the reaction for 22 h. After purification treatment, snowman-shaped 3-APF@mSiO2 Janus particles were obtained.

[0064] Comparative Example 1.

[0065] (1) Weigh 45 g of distilled water, 0.5 g of 3-aminophenol, 20 mL of absolute ethanol, 0.5 g of sodium dodecyl sulfate, and 0.18 g of ammonia water. After ultrasonic dispersion until homogeneous, transfer it into a three-necked flask.

[0066] (2) Under the conditions of a stirring rate of 300 rpm and a temperature of 35 °C, use a syringe pump to dropwise add 1.68 g of TEOS thereto, and set the dropping time to 30 min. After the dropping is completed, add 0.73 g of formaldehyde solution thereto and continue the reaction for 22 h. After purification treatment, spherical particles were obtained.

[0067] Characterize the morphology of the particles by referring to the test method for the surface morphology of the particles in Example 3.

[0068] Example 6

[0069] (1) Weigh 45 g of distilled water, 0.5 g of 3-aminophenol, 20 mL of absolute ethanol, 0.1 g of CTAB, and 0.18 g of ammonia water. After ultrasonic dispersion until homogeneous, transfer it into a three-necked flask.

[0070] (2) Under the conditions of a stirring rate of 300 rpm and a temperature of 35 °C, add 1.68 g of TEOS to the system all at once. After reacting for 30 min, add 0.73 g of formaldehyde solution thereto and continue the reaction for 22 h. After purification treatment, caterpillar-shaped 3-APF@mSiO2 Janus particles were obtained.

[0071] Example 7

[0072] (1) Weigh 45 g of distilled water, 0.5 g of 3-aminophenol, 20 mL of absolute ethanol, 0.2 g of CTAB, and 0.18 g of ammonia water. After ultrasonic dispersion until homogeneous, transfer it into a three-necked flask.

[0073] (2) At a stirring rate of 300 rpm and a temperature of 35°C, 1.68 g of TEOS was added to the system at one time. After reacting for 30 min, 0.73 g of formaldehyde solution was added and the reaction was continued for 22 h. After purification, popcorn-shaped 3-APF@mSiO2 Janus particles were obtained.

[0074] Example 8

[0075] (1) Weigh 45 g of distilled water, 0.5 g of 3-aminophenol, 20 mL of anhydrous ethanol, 0.3 g of CTAB, and 0.18 g of aqueous ammonia, disperse them uniformly by ultrasonication, and transfer them into a three-necked flask.

[0076] (2) At a stirring rate of 300 rpm and a temperature of 35°C, 1.68 g of TEOS was added to the system at one time. After reacting for 30 min, 0.73 g of formaldehyde solution was added and the reaction was continued for 22 h. After purification, hamburger-shaped 3-APF@mSiO2 Janus particles were obtained.

[0077] Example 9

[0078] (1) Weigh 0.5 g of the 3-APF@mSiO2 Janus particles prepared in Example 4 and place them on the filter. Then, drop 2.5 mL of 65 mg / g phen-NH2 ethanol solution onto the 3-APF@mSiO2 Janus particles for 30 min. After drying, rinse off the excess phen-NH2 with 15 mL of anhydrous ethanol.

[0079] (2) 0.01 g of 3-APF@mSiO2 loaded with phen-NH2 was dispersed in 3 mL of distilled water, and then 4.65 g of linseed oil was added thereto. After ultrasonic treatment, an oil-in-water Pickering emulsion was obtained.

[0080] (3) 1 g of the Pickering emulsion prepared in step (2) and 1 g of WPU dispersion (i.e., aqueous polyurethane emulsion, with a concentration of 50 wt%) were mixed evenly by magnetic stirring, and then drop-coated on a tinplate sheet and dried at 45° C. for 24 h to obtain an anti-corrosion coating with a thickness of 0.4 mm having both self-repairing and corrosion self-reporting functions.

[0081] Example 10

[0082] (1) Weigh 0.5 g of the 3-APF@mSiO2 Janus particles prepared in Example 4 and place them on a filter. Then, add dropwise 2.5 mL of an ethanol solution of phen-NH2 with a concentration of 65 mg / g onto the 3-APF@mSiO2 Janus particles over a period of 30 min. After drying, rinse off the excess phen-NH2 with 15 mL of absolute ethanol.

[0083] (2) Disperse 0.015 g of the 3-APF@mSiO2 loaded with phen-NH2 in 3 g of distilled water, and then add 4.65 g of linseed oil thereto. After ultrasonic treatment, an oil-in-water Pickering emulsion is obtained.

[0084] (3) Mix 1 g of the Pickering emulsion prepared in step (2) and 1 g of the WPU dispersion (50 wt%) evenly by magnetic stirring, and then drop-coat the mixture onto a tinplate. Dry it at 45 °C for 24 h to obtain an anti-corrosion coating with both self-healing and corrosion self-reporting functions.

[0085] Example 11

[0086] (1) Weigh 0.5 g of the 3-APF@mSiO2 Janus particles prepared in Example 4 and place them on a filter. Then, add dropwise 2.5 mL of an ethanol solution of phen-NH2 with a concentration of 65 mg / g onto the 3-APF@mSiO2 Janus particles over a period of 30 min. After drying, rinse off the excess phen-NH2 with 15 mL of an ethanol solution.

[0087] (2) Disperse 0.020 g of the 3-APF@mSiO2 loaded with phen-NH2 in 3 mL of distilled water, and then add 4.65 g of linseed oil thereto. After ultrasonic treatment, an oil-in-water Pickering emulsion is obtained.

[0088] (3) Mix 1 g of the Pickering emulsion prepared in step (2) and 1 g of the WPU dispersion evenly by magnetic stirring, and then drop-coat the mixture onto a tinplate. Dry it at 45 °C for 24 h to obtain an anti-corrosion coating with both self-healing and corrosion self-reporting functions.

[0089] Example 12

[0090] (1) Weigh 0.5 g of the 3-APF@mSiO2 Janus particles prepared in Example 4 and place them on a filter. Then, add dropwise 2.5 mL of an ethanol solution of phen-NH2 with a concentration of 65 mg / g onto the 3-APF@mSiO2 Janus particles over a period of 30 min. After drying, rinse off the excess phen-NH2 with 15 mL of absolute ethanol.

[0091] (2) Disperse 0.025 g of phen-NH2-loaded 3-APF@mSiO2 in 3 mL of distilled water, then add 4.65 g of linseed oil thereto, and obtain an oil-in-water Pickering emulsion after ultrasonic treatment.

[0092] (3) Mix 1 g of the Pickering emulsion prepared in step (2) and 1 g of the WPU dispersion evenly by magnetic stirring, then drop-coat it on a tinplate, and dry it at 45 °C for 24 h to obtain an anti-corrosion coating with both self-healing and corrosion self-reporting functions.

[0093] Testing method

[0094] Microscopic test of the coating: Carefully peel the coating from the tinplate, place it on a glass slide, and observe it with an optical microscope of model DMM-3000.

[0095] Morphology test of the coating cross-section: Carefully peel the coating from the tinplate, and then fracture it by liquid nitrogen embrittlement. After sputtering gold on the cross-section, characterize the morphology of the coating cross-section with a Nano 450 type scanning electron microscope of FEI Company, USA.

[0096] Electrochemical test of the coating: Coat the coating on the surface of the tinplate with epoxy resin, leaving 1 cm 2 . Then perform an electrochemical test on the coating using a three-electrode system. Among them, the counter electrode is a platinum electrode, the reference electrode is a calomel electrode, and the electrolyte is a 3.5 wt% NaCl solution.

[0097] Self-healing performance test of the coating: Scratch a scratch with a length of 500 μm and a width of 15 μm on the coating with a craft knife. Then place the scratched coating at room temperature for 48 h and perform a scanning electron microscope test.

[0098] Corrosion self-reporting performance test of the coating: Scratch a scratch with a length of 500 μm and a width of 15 μm on the coating with a craft knife. Then immerse the scratched coating in a 3.5 wt% NaCl solution and observe the color change at the scratch.

[0099] From the attached Figure 1 and the attached Figure 2 It can be seen that snowman-shaped 3-APF@mSiO2 Janus particles were successfully prepared. Attached Figure 3 It can be seen that the particle size of the particles is 247 nm. Comparing the attached Figure 1 and the attached Figure 4 It can be seen that when the emulsifier is an anionic emulsifier sodium dodecyl sulfate, the morphology of the particles is spherical, and when the emulsifier is a cationic emulsifier, the morphology of the particles is snowman-shaped. Thus, it can be known that the positive and negative charge interaction is the main reason for the successful preparation of the particles. From the attached Figure 5and attached Figure 6 It can be seen that the linseed oil capsules are evenly encapsulated in the coating. From Figure 7 it can be seen that the snowman-shaped 3-APF@mSiO2 Janus particles are firmly anchored at the interface between linseed oil and WPU, indicating that the particles act as compatibilizers. Attached Figure 8 indicates that the low-frequency impedance modulus of the prepared coating is as high as 3.89×10 8 ohm·cm 2 , showing good anti-corrosion performance. From attached Figure 9 it can be seen that the scratches on the coating disappear, indicating that the coating has good room-temperature self-healing performance. From attached Figure 10 it can be seen that there are obvious red products at the scratched area (due to the complexation reaction between the color developer in the coating and the corrosion products of iron), indicating that the coating has sensitive corrosion self-reporting performance.

[0100] In summary, the snowman-shaped 3-APF@mSiO2 Janus particles are innovatively prepared by the "one-pot" method in this invention, providing guidance for the preparation of organic-inorganic hybrid Janus particles with precise structure and controllable size by emulsion templating. And by giving full play to the advantages of the snowman-shaped 3-APF@mSiO2 Janus particles themselves, the color developer phen-NH2 and linseed oil are simultaneously introduced into the WPU coating, greatly improving the mechanical properties and anti-corrosion performance of the WPU coating, and at the same time endowing the WPU coating with excellent corrosion self-reporting and room-temperature self-repairing performance for damage. It opens up a new direction for the application of Janus particles in anti-corrosion coatings.

[0101] The content of this invention is not limited to the examples listed. Any equivalent transformation of the technical solution of this invention adopted by those of ordinary skill in the art by reading the specification of this invention shall be covered by the claims of this invention.

[0102] Matters not covered in this invention are well-known technologies.

Claims

1. A preparation method of snowman-shaped 3-APF@mSiO2 Janus particles, characterized by The material composition and proportion are as follows: The steps include: Step (1): according to the above raw material ratio, distilled water, 3-aminophenol, anhydrous ethanol, CTAB and ammonia water are mixed by ultrasonication to obtain a uniform solution; Step (2): TEOS was added dropwise to the above solution under stirring; after the addition was completed, formaldehyde solution was added thereto and the reaction was continued for 20 to 30 hours to obtain snowman-shaped 3-APF@mSiO2 Janus particles.

2. The preparation method of the snowman-shaped 3-APF@mSiO2 Janus particles according to claim 1, characterized in that, The mass percentage concentration of the formaldehyde solution is 30-40%; the mass percentage concentration of the ammonia water is 20-30%.

3. The preparation method of the snowman-shaped 3-APF@mSiO2 Janus particles according to claim 1, characterized in that, In step (2), the stirring rate is 150-500 rpm and the reaction temperature is 25-65°C.

4. The preparation method of the snowman-shaped 3-APF@mSiO2 Janus particles according to claim 1, characterized in that, In step (2), the TEOS is added dropwise for 10 to 80 minutes.

5. The preparation method of the snowman-shaped 3-APF@mSiO2 Janus particles according to claim 1, characterized in that, The particle size of the prepared snowman-shaped 3-APF@mSiO2 Janus particles is 90-500 nm; The size of the mSiO2 end is 40-130 nm, and the size of the mesopore is 1-5 nm, and the size of the 3-APF end is 40-300 nm.

6. Application of the snowman-shaped 3-APF@mSiO2 Janus particles prepared by the method of claim 1, characterized in that they are used to prepare intelligent anti-corrosion coatings with corrosion self-reporting and self-repairing properties.

7. The application according to claim 6, characterized in that, The steps include: Step (1): dissolving phen-NH2 in anhydrous ethanol to obtain a phen-NH2 ethanol solution with a concentration of 25 to 90 mg / L; Step (2): dripping the ethanol solution of phen-NH2 obtained in step (1) onto the snowman-shaped 3-APF@mSiO2Janus particle powder by an impregnation method, and obtaining snowman-shaped 3-APF@mSiO2 Janus particles loaded with phen-NH2 after drying; Among them, 2.5 mL of phen-NH2 ethanol solution was added to every 0.1-1 g of snowman-shaped 3-APF@mSiO2 Janus particle powder; Step (3): ultrasonically dispersing the snowman-shaped 3-APF@mSiO2 Janus particles loaded with phen-NH2 and distilled water to obtain a particle dispersion; Among them, 0.010-0.025 g of snowman-shaped 3-APF@mSiO2Janus particles loaded with phen-NH2 were added to every 2-6 mL of distilled water; Step (4): adding linseed oil to the above dispersion, and dispersing it uniformly by ultrasonication to obtain an O / W type Pickering emulsion; Wherein, 2 to 6 mL of linseed oil is added for every 2 to 6 mL of dispersion; Step (5): the obtained Pickering emulsion and aqueous polyurethane emulsion are stirred evenly and then drop-coated on the substrate to obtain an intelligent anti-corrosion coating with both corrosion self-reporting and self-repairing properties; Wherein, the mass ratio of Pickering emulsion to waterborne polyurethane is 1:(1-2).

8. The application according to claim 7, characterized in that, In step (4), the particle size of the Pickering emulsion oil droplets is 45 μm to 150 μm.

9. The application according to claim 7, characterized in that, The substrate in step (5) is tinplate and glass.

10. The application according to claim 7, characterized in that, The thickness of the anti-corrosion coating obtained in step (5) is 100 to 800 μm; the concentration of the aqueous polyurethane emulsion is 40 to 60 wt%.

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