CN110449094B - Preparation method of self-repairing microcapsule and application of self-repairing microcapsule in super-hydrophobic coating - Google Patents

Abstract

The invention relates to a preparation method of a self-repairing microcapsule and application of the self-repairing microcapsule in a super-hydrophobic coating. The self-repairing microcapsule provided by the invention adopts the porous nanoparticles wrapped with low surface energy as the capsule core, the nano-scale porous particle structure can enable the nanoparticles to fill cracks when the microcapsule is damaged by acid and alkali, so as to play a self-repairing role, the porous structure can increase the specific surface area of the capsule core, increase the surface energy and further have stronger surface adsorption capacity, so that a low-surface-energy substance can be more easily adsorbed on the surface of the capsule core, and the microcapsule has a better self-repairing effect when the pH value is 5-9; the capsule wall of the microcapsule is selected from high molecular polymers, and through the synergistic action of the capsule wall and the capsule wall, when the structure of the capsule wall is damaged, the surface of the capsule still has high roughness, and through the synergistic action of the capsule wall and the capsule wall, the damaged superhydrophobic surface can be automatically repaired.

Description

Preparation method of self-repairing microcapsule and application of self-repairing microcapsule in super-hydrophobic coating

Technical Field

The invention belongs to the technical field of super-hydrophobic materials, and particularly relates to a preparation method of a self-repairing microcapsule and application of the self-repairing microcapsule in a super-hydrophobic coating.

Background

The super-hydrophobic surface (the contact angle is more than 150 degrees and the rolling angle is less than 10 degrees) has excellent performance, so the super-hydrophobic surface has wide application prospect in a plurality of fields, such as self-cleaning, corrosion resistance, ice coating prevention, drag reduction, antifouling and the like. However, the artificial super-hydrophobic surface has poor durability in the actual use process, easily loses super-hydrophobic performance due to physical damage such as scraping and abrasion and the like, and greatly limits the application of the super-hydrophobic material.

The present invention has been made in view of the above circumstances.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a preparation method of a self-repairing microcapsule and application of the self-repairing microcapsule in a super-hydrophobic coating.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a self-repairing microcapsule comprises the following steps:

(1) firstly, preparing porous nano particles;

(2) adding the prepared porous nanoparticles into a mixture with a volume ratio of 2: 1, stirring and dissolving the mixed solution of deionized water and ethanol, adding a low-surface-energy substance into the mixed solution, and stirring for 2-3 hours to form a mixed solution A to obtain a capsule;

(3) respectively dissolving polyglutamic acid and acrylic acid in 0.1mol/L phosphate buffer solution, adding initiator ammonium sulfate under the condition of stirring, stirring for 25-35min, then adding tetramethylethylenediamine, stirring for 1.8-2.2h to form mixed solution B, dropwise adding the mixed solution A into the mixed solution B, stirring for 2-3h, cleaning, drying at 50-60 ℃, and grinding to obtain the self-repairing microcapsule.

Further, the porous nanoparticles in the step (1) are one or more of porous titanium dioxide nanoparticles, porous zinc oxide nanoparticles and porous silicon dioxide nanoparticles.

Further, the porous titanium dioxide nano particle is prepared by the following method: sequentially adding ethanol, tetrabutyl orthotitanate, diethanolamine and glacial acetic acid into a beaker according to the volume ratio of 1:0.5:0.05:0.8, stirring for 2-3h to form milky suspension, aging for 12h, pouring out supernatant, centrifugally cleaning for 3 times by using acetone to remove impurity ions, drying for 12h at 60 ℃, grinding to obtain powdery titanium dioxide, and calcining the powdery titanium dioxide at 400 ℃ for 3-4h to obtain porous titanium dioxide nanoparticles;

further, the porous zinc oxide nanoparticles are prepared by the following method: dissolving 2.2g of zinc acetate in 15-25ml of ethanolamine, adding a mixed solution of deionized water and ethanol with a volume ratio of 1:1-3, stirring for 25-35min, reacting at 180 ℃ for 4-8h at 170-;

further, the porous silica nanoparticles are prepared by the following method: dissolving 0.5g of polyvinylpyrrolidone in a mixed solution of 40ml of ethanol and 60ml of deionized water, dissolving 1g of dodecylamine in 5ml of anhydrous ethanol, adding the mixture, stirring for 50-70min, adding 5ml of ethyl orthosilicate, stirring for 5-7h at 30-50 ℃ to form white colloid, centrifugally cleaning, drying for 12h at 100 ℃, grinding, and calcining for 3.5-4.5h at 550-650 ℃ to obtain the porous silica nanoparticles.

Further, in the step (2), according to parts by weight, 15-30 parts of porous nano particles, 20-30 parts of a mixed solution of deionized water and ethanol and 1-4 parts of a low surface energy substance.

Further, the low surface energy substance in the step (2) is one or more of zinc tridecafluoro-based triethoxysilane, 1H,2H, 2H-perfluorooctyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane and octadecyltrimethoxysilane.

Further, in the step (3), the mass ratio of the polyglutamic acid to the acrylic acid to the ammonium sulfate to the tetramethylethylenediamine is 3:7:0.55:0.043, and the mass-to-volume ratio of the polyglutamic acid to the phosphate buffer solution is 0.03 g: 5 ml.

The self-repairing microcapsule prepared by the method is applied to a super-hydrophobic coating.

Further, the sensitive range of the pH value of the super-hydrophobic coating is 5-9.

Namely, the pH value is between 5 and 9, the super-hydrophobic coating prepared by the invention has a good self-repairing effect, and the hydrophobic property and the durability are durable and stable.

Further, the super-hydrophobic coating comprises the following raw materials in parts by weight: 15-20 parts of acrylic resin, 15-30 parts of solvent, 5-20 parts of microcapsule, 1-3 parts of surfactant, 10-20 parts of hydrophobic substance, 1-5 parts of defoaming agent, 1-5 parts of flatting agent and 2-8 parts of curing agent.

Further, the solvent is one or more of toluene, xylene, acetone, polyamide and tetrahydrofuran, the surfactant is polyvinylpyrrolidone or hexadecyl trimethyl ammonium bromide, the hydrophobic substance is one or more of paraffin, talcum powder, bentonite, tridecafluoro zinc-based triethoxysilane, 1H,2H, 2H-perfluoro octyl trimethoxysilane, dodecyl trimethoxysilane, hexadecyl trimethoxysilane and octadecyl trimethoxysilane, the defoaming agent is polydimethylsiloxane or polypropylene glycol-alkylene oxide polymer, the leveling agent is polyether modified polysiloxane, the curing agent is one or more of benzoyl peroxide, cumyl hydroperoxide, tert-butyl hydroperoxide, benzoyl peroxide and cyclohexanone peroxide.

Further, the preparation method of the super-hydrophobic coating comprises the following steps:

(a) pretreatment of a base material: selecting silicon dioxide glass as a substrate, immersing the substrate in ethanol, ultrasonically cleaning for 15-20min, cleaning with ultrapure water for three times, drying, and wrapping with a preservative film for later use;

(b) the super-hydrophobic coating is prepared by the following method: according to the weight of each raw material, dissolving acrylic resin in a solvent, sequentially adding microcapsules, a surfactant, a hydrophobic substance, a defoaming agent, a flatting agent and a curing agent, uniformly stirring by ultrasonic waves, coating on a standby base material, and curing at the temperature of 100-110 ℃.

The prepared super-hydrophobic coating can be used in the fields of outdoor buildings, glass, metal, textiles and the like.

Compared with the prior art, the invention has the beneficial effects that:

(1) the self-repairing microcapsule provided by the invention adopts the porous nanoparticles wrapped with low surface energy as the capsule core, the nano-scale porous particle structure can enable the nanoparticles to fill cracks when the microcapsule is damaged by acid and alkali, so as to play a self-repairing role, the porous structure can increase the specific surface area of the capsule core, increase the surface energy and further have stronger surface adsorption capacity, so that a low-surface-energy substance can be more easily adsorbed on the surface of the capsule core, and the microcapsule has a better self-repairing effect when the pH value is 5-9; the capsule wall of the microcapsule is made of high molecular polymer, the high molecular polymer contains a group with pH response characteristics of weak acid or weak base, such as carboxyl, amino and the like, the weak acid or weak base group can be ionized along with the change of pH value and ionic strength, hydrogen bond dissociation can be carried out, polymerization swelling is caused, the surface of the capsule core still has high roughness through the synergistic action of the capsule core and the capsule wall when the structure of the capsule wall is damaged, and the damaged superhydrophobic surface can be automatically repaired through the synergistic action of the capsule wall and the capsule core;

(2) the prepared super-hydrophobic coating can timely release low surface energy substances in a pH sensitive range and the porous nanoparticles can fill cracks to achieve a self-repairing effect, so that the hydrophobic property and the durability of the super-hydrophobic coating are durable and stable.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a transmission electron micrograph of porous titania nanoparticles prepared in example 1;

FIG. 2 is the contact angle of the superhydrophobic coating prepared in example 4;

FIG. 3 is a contact angle of the superhydrophobic coating prepared in example 4 after treatment with an acid solution having a pH of 5;

fig. 4 is a contact angle of the superhydrophobic coating prepared in example 4 after treatment with an alkali solution having a pH of 9.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the examples given herein without any inventive step, are within the scope of the present invention.

Example 1

The preparation method of the self-repairing microcapsule of the embodiment includes the following steps:

(1) firstly, preparing porous titanium dioxide nano particles: the porous titanium dioxide nano particle is prepared by the following method: sequentially adding ethanol, tetrabutyl orthotitanate, diethanolamine and glacial acetic acid into a beaker according to the volume ratio of 1:0.5:0.05:0.8, stirring for 2h to form a milky suspension, aging for 12h, pouring out a supernatant, centrifugally cleaning for 3 times by using acetone to remove impurity ions, drying for 12h at 60 ℃, grinding to obtain powdery titanium dioxide, and calcining the powdery titanium dioxide for 3h at 300 ℃ to obtain porous titanium dioxide nanoparticles;

(2) adding the prepared porous titanium dioxide nano particles into a reactor with the volume ratio of 2: 1, adding a low-surface-energy substance into the mixed solution of deionized water and ethanol, and stirring for 2.5 hours to form a mixed solution A to obtain a capsule, wherein the capsule comprises 15g of porous titanium dioxide nanoparticles, 20g of the mixed solution of deionized water and ethanol, 1g of the low-surface-energy substance, and the low-surface-energy substance is tridecafluoro zinc-based triethoxysilane;

(3) respectively dissolving 3g of polyglutamic acid and 7g of acrylic acid in 500ml of 0.1mol/L phosphate buffer solution, adding 0.55g of ammonium sulfate serving as an initiator under the stirring condition, stirring for 30min, then adding 0.043g of tetramethylethylenediamine, stirring for 2h to form a mixed solution B, dropwise adding the mixed solution A into the mixed solution B, stirring for 2.5h, washing with deionized water, drying at 55 ℃, and grinding to obtain the self-repairing microcapsule.

The transmission electron microscope image of the porous titania nanoparticles prepared in this example is shown in fig. 1.

The pore diameter of the micropores of the porous titanium dioxide nanoparticles is reduced with the increase of the calcination temperature, the specific surface area is reduced, the crystallinity of the crystal grains is increased, and the average particle diameter of the nanoparticles is increased, as shown in fig. 1, the pores formed by the porous titanium dioxide nanoparticles prepared in the embodiment at the calcination temperature of 300 ℃ have smaller pore diameter, the pore diameter is 1-2nm, the particle diameter is 10-12nm, and the pore diameter change is not obvious. The applicant has carried out a number of experiments and has found that when the calcination temperature is increased to 400 c, titanium dioxide in anatase form is formed. However, when the calcination temperature is too high, the porous structure is shrunk or collapsed, the specific surface area is greatly reduced, the specific surface energy is reduced, the adsorption quantity of low-surface substances is further influenced, and the hydrophobic effect of the coating is poor.

Example 2

The preparation method of the self-repairing microcapsule of the embodiment includes the following steps:

(1) firstly, preparing porous zinc oxide nano particles: the porous zinc oxide nano-particles are prepared by the following method: dissolving 2.2g of zinc acetate in 20ml of ethanolamine, adding 10ml of a mixed solution of deionized water and ethanol in a volume ratio of 1:2, stirring for 30min, then reacting at 175 ℃ for 6h at constant temperature, centrifugally cleaning to neutrality, drying at 60 ℃ for 12h, grinding, and calcining at 350 ℃ for 3.5h to obtain porous zinc oxide nanoparticles;

(2) adding the prepared porous zinc oxide nano particles into a mixture with the volume ratio of 2: 1, stirring and dissolving in a mixed solution of deionized water and ethanol, adding a low surface energy substance into the mixed solution, and stirring for 2 hours to form a mixed solution A, thereby obtaining a capsule core, wherein the porous zinc oxide nanoparticles are 22g, the mixed solution of deionized water and ethanol is 25g, the low surface energy substance is 2.5g, and the low surface energy substance is dodecyl trimethoxy silane;

(3) respectively dissolving 3g of polyglutamic acid and 7g of acrylic acid in 500ml of 0.1mol/L phosphate buffer solution, adding 0.55g of ammonium sulfate serving as an initiator under the stirring condition, stirring for 30min, then adding 0.043g of tetramethylethylenediamine, stirring for 1.8h to form a mixed solution B, dropwise adding the mixed solution A into the mixed solution B, stirring for 2h, washing with deionized water, drying at 50 ℃, and grinding to obtain the self-repairing microcapsule.

Example 3

The preparation method of the self-repairing microcapsule of the embodiment includes the following steps:

(1) firstly, preparing porous silicon dioxide nano particles: the porous silicon dioxide nano particle is prepared by the following method: dissolving 0.5g of polyvinylpyrrolidone in a mixed solution of 40ml of ethanol and 60ml of deionized water, dissolving 1g of dodecylamine in 5ml of absolute ethanol, adding the solution, stirring for 60min, adding 5ml of ethyl orthosilicate, stirring for 6 hours at 40 ℃ to form a white colloid, centrifugally cleaning, drying for 12 hours at 100 ℃, grinding, and calcining for 4 hours at 600 ℃ to obtain porous silica nanoparticles;

(2) adding the prepared porous silica nano particles into a mixture with the volume ratio of 2: 1, stirring and dissolving in a mixed solution of deionized water and ethanol, and adding a low-surface-energy substance into the mixed solution for stirring for 2 hours to form a mixed solution A, thereby obtaining a capsule, wherein the capsule comprises 30g of porous silicon dioxide nanoparticles, 30g of a mixed solution of deionized water and ethanol, 4g of a low-surface-energy substance, and the low-surface-energy substance is 1H,1H,2H, 2H-perfluorooctyltrimethoxysilane;

(3) respectively dissolving 1.5g of polyglutamic acid and 3.5g of acrylic acid in 250ml of 0.1mol/L phosphate buffer solution, adding 0.275g of ammonium sulfate serving as an initiator under the stirring condition, stirring for 30min, then adding 0.0215g of tetramethylethylenediamine, stirring for 2.2h to form a mixed solution B, dropwise adding the mixed solution A into the mixed solution B, stirring for 3h, washing with deionized water, drying at 60 ℃, and grinding to obtain the self-repairing microcapsule.

Example 4

In this embodiment, for the application of the self-repairing microcapsule prepared in embodiment 1 in the superhydrophobic coating, the raw materials for preparing the superhydrophobic coating include: 15g of acrylic resin, 15g of solvent, 5g of microcapsule prepared in example 1, 1g of surfactant, 10g of hydrophobic substance, 1g of defoaming agent, 1g of leveling agent and 2g of curing agent; wherein, the solvent is toluene, the surfactant is polyvinylpyrrolidone, the hydrophobic substance is tridecafluoro zinc-based triethoxysilane, the defoamer is polydimethylsiloxane, the leveling agent is polyether modified polysiloxane (the manufacturer Hubei New Sihai chemical industry Co., Ltd.), and the curing agent is benzoyl peroxide;

the preparation method of the super-hydrophobic coating comprises the following steps:

(a) pretreatment of a base material: selecting silicon dioxide glass as a substrate, immersing the substrate in ethanol, ultrasonically cleaning for 15min, cleaning with ultrapure water for three times, drying, and wrapping with a preservative film for later use;

(b) the super-hydrophobic coating is prepared by the following method: dissolving acrylic resin in a solvent, sequentially adding microcapsules, a surfactant, a hydrophobic substance, a defoaming agent, a flatting agent and a curing agent, uniformly stirring by ultrasonic waves, coating the mixture on a standby base material, and curing at 100 ℃.

Example 5

This example is an application of the self-repairing microcapsule prepared in example 2 in a superhydrophobic coating, and the raw materials for preparing the superhydrophobic coating include the following: 17.5g of acrylic resin, 22.5g of solvent, 12.5g of microcapsule prepared in example 2, 2g of surfactant, 15g of hydrophobic substance, 3g of defoaming agent, 3g of flatting agent and 5g of curing agent; wherein, the solvent is tetrahydrofuran, the surfactant is cetyl trimethyl ammonium bromide, the hydrophobic substance is dodecyl trimethoxy silane, the antifoaming agent is a polypropylene glycol-alkylene oxide polymer, the flatting agent is polyether modified polysiloxane (chemical industry Co., Ltd., New four seas, Hubei of manufacturers), and the curing agent is cumene hydroperoxide;

the preparation method of the super-hydrophobic coating comprises the following steps:

(a) pretreatment of a base material: selecting silicon dioxide glass as a substrate, immersing the substrate in ethanol, ultrasonically cleaning for 17.5min, cleaning with ultrapure water for three times, drying, and wrapping with a preservative film for later use;

(b) the super-hydrophobic coating is prepared by the following method: dissolving acrylic resin in a solvent, sequentially adding microcapsules, a surfactant, a hydrophobic substance, a defoaming agent, a flatting agent and a curing agent, uniformly stirring by ultrasonic waves, coating on a standby base material, and curing at 105 ℃.

Example 6

This example is an application of the self-repairing microcapsule prepared in example 3 in a superhydrophobic coating, and the raw materials for preparing the superhydrophobic coating include the following: 20g of acrylic resin, 30g of solvent, 20g of microcapsule prepared in example 3, 3g of surfactant, 20g of hydrophobic substance, 5g of defoaming agent, 5g of flatting agent and 8g of curing agent; wherein, the solvent is acetone, the surfactant is cetyl trimethyl ammonium bromide, the hydrophobic substance is 1H,1H,2H, 2H-perfluorooctyl trimethoxy silane, the defoaming agent is a polypropylene glycol-alkylene oxide polymer, the flatting agent is polyether modified polysiloxane (the manufacturer Hubei New Sihai chemical industry Co., Ltd.), and the curing agent is benzoyl peroxide;

the preparation method of the super-hydrophobic coating comprises the following steps:

(a) pretreatment of a base material: selecting silicon dioxide glass as a substrate, immersing the substrate in ethanol, ultrasonically cleaning for 20min, cleaning with ultrapure water for three times, drying, and wrapping with a preservative film for later use;

(b) the super-hydrophobic coating is prepared by the following method: dissolving acrylic resin in a solvent, sequentially adding microcapsules, a surfactant, a hydrophobic substance, a defoaming agent, a flatting agent and a curing agent, uniformly stirring by ultrasonic waves, coating on a standby base material, and curing at 110 ℃.

Comparative example 1

The superhydrophobic coating prepared by the comparative example is the same as that prepared in example 4, except that the porous titanium dioxide nanoparticles are directly ground and crushed without calcining in the preparation process.

Test example 1

The self-healing performance of the superhydrophobic coating prepared by the method of example 4 under acid-base conditions was tested.

Hydrophobicity test method: the contact angle of a water drop on the surface of the film layer is measured by a contact angle tester, the contact angle value is obtained by averaging 5 random position measurement values, the static contact angle is measured by a lying drop method (sessile drop), and when a super-hydrophobic surface (namely a surface with the static contact angle larger than 150 degrees) is measured, 5 mu L of water drop is uniformly used during measurement.

1. The contact angle of the superhydrophobic coating prepared in test example 4 was 159.12 ° according to the hydrophobicity test method described above, and is shown in fig. 2.

2. Acid solutions with pH 4, 5 and 6 were prepared with hydrochloric acid, and base solutions with pH 8, 9 and 10 were prepared with sodium hydroxide, respectively.

6 groups of sample coatings are respectively prepared according to the method of the embodiment 4 to test the self-repairing performance of the super-hydrophobic coatings under different acid and alkali conditions, and the test method is as follows: respectively immersing the sample coating in solutions with different pH values for 24h, then removing the coating, removing acid-base solution on the surface, measuring the contact angle, then placing the coating in an environment with the temperature of 80 ℃ for repairing for 2h, and measuring the contact angle of the coating, wherein the results are shown in table 1.

TABLE 1

pH of the treated solution	Contact angle (°) after treatment with acid or alkali solution	Contact Angle after restoration (°)
			4	132.14	138.95
5	153.26	158.16
			6	154.49	158.87
8	153.62	158.71
			9	154.03	158.83
10	134.62	139.82

As can be seen from Table 1, the repairing performance of the coating is better when the pH is 5-9, and the repairing effect is poorer when the pH is less than 5 or more than 9, which shows that the super-hydrophobic coating of the invention has better self-repairing effect when the pH is 5-9, and when the super-hydrophobic coating of the invention is damaged by a solution with the pH of 5-9, the stable hydrophobic performance can be maintained.

Wherein, the contact angle of the super-hydrophobic coating after the treatment of the acid solution with pH 5 is shown in FIG. 3, and the contact angle of the super-hydrophobic coating after the treatment of the alkali solution with pH 9 is shown in FIG. 4.

The inventors also conducted the above tests on the superhydrophobic coatings prepared in other examples, and the results were substantially consistent and are not listed due to limited space.

Test example 2

In the test example, the super-hydrophobic coating prepared in comparative example 1 was tested for self-repairing performance under acid and alkali conditions, the test method was the same as in test example 1, and the measurement results are shown in table 2.

1. The contact angle of the superhydrophobic coating prepared in comparative example 1 was 153.12 °.

TABLE 2

pH of the treated solution	Contact angle (°) after treatment with acid or alkali solution	Contact Angle after restoration (°)
			4	123.45	127.56
5	146.32	148.28
			6	147.56	147.98
8	145.85	146.13
			9	146.38	148.23
10	114.62	123.87

It can be seen from tables 1 and 2 that the self-repairing performance of the hydrophobic coating of the nano titanium dioxide without calcination treatment is poorer than that of the hydrophobic coating with calcination treatment, and the contact angle is small, i.e. the hydrophobicity is also reduced, because the calcination treatment increases the holes on the surface of the porous nano particles to increase the surface area, the adsorption performance of the low surface energy substance is stronger, the self-repairing effect is better, and the hydrophobic performance is better.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims (8)

1. A preparation method of a self-repairing microcapsule is characterized by comprising the following steps:

(1) firstly, preparing porous nano particles;

(2) adding the prepared porous nanoparticles into a mixture with a volume ratio of 2: 1, stirring and dissolving the mixed solution of deionized water and ethanol, adding a low-surface-energy substance into the mixed solution, and stirring for 2-3 hours to form a mixed solution A to obtain a capsule;

(3) respectively dissolving polyglutamic acid and acrylic acid in 0.1mol/L phosphate buffer solution, adding an initiator ammonium sulfate under the stirring condition, stirring for 25-35min, then adding tetramethylethylenediamine, stirring for 1.8-2.2h to form a mixed solution B, dropwise adding the mixed solution A into the mixed solution B, stirring for 2-3h, cleaning, drying at 50-60 ℃, and grinding to obtain the self-repairing microcapsule;

wherein the porous nanoparticles in the step (1) are one or more of porous titanium dioxide nanoparticles, porous zinc oxide nanoparticles and porous silicon dioxide nanoparticles;

the porous titanium dioxide nano particle is prepared by the following method: sequentially adding ethanol, tetrabutyl orthotitanate, diethanolamine and glacial acetic acid into a beaker according to the volume ratio of 1:0.5:0.05:0.8, stirring for 2-3h to form milky suspension, aging for 12h, pouring out supernatant, centrifugally cleaning for 3 times by using acetone to remove impurity ions, drying for 12h at 60 ℃, grinding to obtain powdery titanium dioxide, and calcining the powdery titanium dioxide at 400 ℃ for 3-4h to obtain porous titanium dioxide nanoparticles;

the porous zinc oxide nano particles are prepared by the following method: dissolving 2.2g of zinc acetate in 15-25ml of ethanolamine, adding a mixed solution of deionized water and ethanol with a volume ratio of 1:1-3, stirring for 25-35min, reacting at 180 ℃ for 4-8h at 170-;

the porous silicon dioxide nano particle is prepared by the following method: dissolving 0.5g of polyvinylpyrrolidone in a mixed solution of 40ml of ethanol and 60ml of deionized water, dissolving 1g of dodecylamine in 5ml of anhydrous ethanol, adding the mixture, stirring for 50-70min, adding 5ml of ethyl orthosilicate, stirring for 5-7h at 30-50 ℃ to form white colloid, centrifugally cleaning, drying for 12h at 100 ℃, grinding, and calcining for 3.5-4.5h at 550-650 ℃ to obtain the porous silica nanoparticles.

2. The preparation method of the self-repairing microcapsule according to claim 1, wherein in the step (2), the porous nanoparticles are 15-30 parts by weight, the mixed solution of deionized water and ethanol is 20-30 parts by weight, and the low surface energy substance is 1-4 parts by weight.

3. The method for preparing the self-repairing microcapsule according to claim 1 or 2, wherein the low surface energy substance in the step (2) is one or more of tridecafluoro zinc-based triethoxysilane, 1H,2H, 2H-perfluorooctyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane and octadecyltrimethoxysilane.

4. The preparation method of the self-repairing microcapsule according to claim 1, wherein the mass ratio of the polyglutamic acid, the acrylic acid, the ammonium sulfate and the tetramethylethylenediamine in the step (3) is 3:7:0.55:0.043, and the mass-volume ratio of the polyglutamic acid to the phosphate buffer is 0.03 g: 5 ml.

5. Use of self-healing microcapsules prepared according to the process of any one of claims 1 to 4 in superhydrophobic coatings.

6. The application of the self-repairing microcapsule to the super-hydrophobic coating, which is characterized in that the super-hydrophobic coating comprises the following raw materials in parts by weight: 15-20 parts of acrylic resin, 15-30 parts of solvent, 5-20 parts of microcapsule, 1-3 parts of surfactant, 10-20 parts of hydrophobic substance, 1-5 parts of defoaming agent, 1-5 parts of flatting agent and 2-8 parts of curing agent.

7. The use of the self-repairing microcapsule of claim 6 in a superhydrophobic coating, wherein the solvent is one or more of toluene, xylene, acetone, polyamide, tetrahydrofuran, the surfactant is polyvinylpyrrolidone or cetyltrimethylammonium bromide, the hydrophobic material is one or more of paraffin, talc, bentonite, tridecafluoro-zinc-based triethoxysilane, 1H,2H, 2H-perfluorooctyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, octadecyltrimethoxysilane, the antifoaming agent is polydimethylsiloxane or polypropylene glycol-alkylene oxide polymer, the leveling agent is polyether-modified polysiloxane, and the curing agent is benzoyl peroxide, cumene hydroperoxide, or octadecyl trimethoxysilane, One or more of tert-butyl hydroperoxide, benzoyl peroxide and cyclohexanone peroxide.

8. The application of the self-repairing microcapsule to the super-hydrophobic coating, which is characterized in that the preparation method of the super-hydrophobic coating comprises the following steps:

(a) pretreatment of a base material: selecting silicon dioxide glass as a substrate, immersing the substrate in ethanol, ultrasonically cleaning for 15-20min, cleaning with ultrapure water for three times, drying, and wrapping with a preservative film for later use;

(b) the super-hydrophobic coating is prepared by the following method: according to the weight of each raw material, dissolving acrylic resin in a solvent, sequentially adding microcapsules, a surfactant, a hydrophobic substance, a defoaming agent, a flatting agent and a curing agent, uniformly stirring by ultrasonic waves, coating on a standby base material, and curing at the temperature of 100-110 ℃.

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