Porous double-effect self-cleaning coating and preparation method thereof

Abstract

The invention belongs to the field of self-cleaning coatings, and discloses a preparation method of a porous double-effect self-cleaning coating, which comprises the following steps: (1) mixing water with ethanol, and adding acid to adjust the pH value to 1.0-4.0 to prepare a solution A; mixing glacial acetic acid, tetrabutyl titanate and absolute ethyl alcohol, and then adding UIO-66 powder to prepare a suspension B; under strong stirring, slowly dropwise adding the solution A into the suspension B, stopping stirring after dropwise adding, standing until white colloid is formed, and then drying to obtain UIO-66 (at) TiO2 powder; (2) calcining the UIO-66 (at) TiO2 powder for 0.5 to 3 hours at the temperature of between 300 and 500 DEG C, so as to obtain porous ZrO2 (at) TiO2 powder; and (3) dispersing the ZrO2 (at) TiO2 powder and PDMS in normal hexane, and carrying out ultrasonic treatment to obtain the porous double-effect self-cleaning coating. The coating has an excellent self-cleaning effect and excellent photocatalytic performance.

Description

Technical Field

[0001] The present invention belongs to the field of self-cleaning coatings, and particularly relates to the preparation and application of a porous dual-effect self-cleaning coating. Background Art

[0002] Superhydrophobic coatings mimic the "lotus effect" and modify the coating with micro-nano structures and low surface energy materials to endow the coating with superhydrophobicity, enabling water droplets to roll off and carry away dust on the surface to achieve physical self-cleaning. However, in practical applications, since organic pollutants such as grease and dyes are easily adhered to the coating surface and are not easily removed by water, the hydrophobic structure of the coating is damaged, the hydrophobicity gradually decreases, and finally the superhydrophobic self-cleaning performance is lost. Therefore, a photocatalyst can be added to the coating to solve this problem. Utilizing the porosity and photocatalytic activity of the nano-material structure to adsorb and catalyze organic pollutants, which are decomposed into small molecules such as carbon dioxide and water under light irradiation, so that the original superhydrophobicity can be restored to achieve chemical self-cleaning. In this way, water droplets can roll to remove inorganic substances on the surface, and organic substances can be degraded by light irradiation, thereby achieving a dual-effect self-cleaning effect. Dual-effect self-cleaning coatings can be applied to anti-fouling coatings through various micro-nano processes such as spraying, dip coating, spin coating, chemical vapor deposition, etc., and are widely applicable to various fields such as fabric clothing, building materials, transportation vehicles, energy and chemical industries, showing broad application prospects in many fields such as durability, flame retardancy, moisture resistance, and oil-water separation.

[0003] Currently, there is little research on dual-effect self-cleaning coatings, and there are still key technical problems: First, semiconductor photocatalysts such as TiO 2 will generate electron-hole pairs under light irradiation and react with water and oxygen adsorbed on the surface to generate reactive free radicals. Due to the electron and inductive effects of fluorine-containing low surface energy materials, these reactive free radicals are more likely to attack the hydrophobic groups and break their chemical bonds, thus losing the superhydrophobic ability. Second, compared with the direct hydrophobic and oleophobic effects of traditional fluorine-containing super-dual-hydrophobic coatings, the process of photocatalytic degradation of organic pollutants by dual-effect self-cleaning coatings is too slow, and it often takes a lot of time to decompose them. Therefore, selecting low surface energy materials that are not easily degraded and improving the photocatalytic rate of the coating are the research focuses of dual-effect self-cleaning coatings. Summary of the Invention

[0004] The purpose of the present invention is to provide the preparation and application of a porous dual-effect self-cleaning coating. This coating is co-sintered by TiO 2 and UIO-66(Zr) at a certain temperature to prepare a porous ZrO 2 @TiO 2Heterojunction micro-nano photocatalyst. Then it is mixed with PDMS in a certain proportion, and finally sprayed on the surface of various substrates to obtain a superhydrophobic effect with a contact angle > 160° and a rolling angle < 2°. And the degradation rate of rhodamine B by the coating is as high as 97.8% after 100 minutes of light irradiation, and it has good mechanical wear resistance, flame retardancy, moisture resistance, oil-water separation and other properties.

[0005] The object of the present invention is achieved by the following technical solutions:

[0006] A preparation method of a porous dual-functional self-cleaning coating, comprising the following steps:

[0007] (1) Synthesis of UIO-66@TiO 2 : Mix water and ethanol, adjust the pH to 1.0 - 4.0 with an acid to make solution A; mix glacial acetic acid, tetrabutyl titanate and absolute ethanol, and then add UIO-66 powder to make suspension B; under strong stirring, slowly drip solution A into suspension B, stop stirring after dripping, let it stand until a white colloid is formed, and then dry to obtain UIO-66@TiO 2 powder;

[0008] (2) Preparation of ZrO 2 @TiO 2 powder: Calcinate the UIO-66@TiO 2 powder prepared in step (1) at 300°C - 500°C for 0.5 - 3 h to obtain porous ZrO 2 @TiO 2 powder;

[0009] (3) Preparation of ZrO 2 @TiO 2 @PDMS coating: Disperse the ZrO 2 @TiO 2 powder prepared in step (2) and PDMS in a hexane solution and perform ultrasonic treatment to obtain the porous dual-functional self-cleaning coating.

[0010] Preferably, the volume ratio of water to ethanol in solution A in step (1) is 1:1 - 1:3; the volume ratio of glacial acetic acid, TBT and absolute ethanol in suspension B is 1:2 ± 1:6 ± 2.

[0011] Preferably, the solid content of UIO-66 in suspension B in step (1) is 100 - 1000 g / L.

[0012] Preferably, the mass ratio of the ZrO 2 @TiO 2 powder to PDMS in step (3) is 1:(0.5 - 3).

[0013] Preferably, the mass-volume ratio of the ZrO 2 @TiO 2 powder to n-hexane is 10 - 100 g / L, and the mass-volume ratio of PDMS to n-hexane is 10 - 100 g / L; the ultrasonic treatment is carried out at a power of 200 ± 50 W for 30 - 60 min.

[0014] Preferably, in step (2), the calcination temperature is 380°C - 450°C, and the calcination time is 90 - 150 min.

[0015] Preferably, in step (1), the pH is 2 - 3, and the standing time is 12 - 24 h.

[0016] Preferably, for the synthesis of UIO-66 powder in step (1): Dissolve zirconium chloride powder and terephthalic acid powder in N,N-dimethylformamide, add acetic acid as a catalyst, place the suspension in an ultrasonic instrument with a power of 200 ± 50 W for ultrasonic treatment for 30 - 60 min, stir for 30 min - 1 h, then heat at 130 ± 20°C for 6 - 48 h, cool, and centrifuge and dry to obtain UIO-66 powder.

[0017] The concentration of the zirconium chloride powder is preferably 10 - 20 g / L, the concentration of the terephthalic acid powder is preferably 8 - 15 g / L, and the concentration of acetic acid is preferably 20% - 50%.

[0018] A porous dual-effect self-cleaning coating. Spray the said coating onto a substrate and cure it to obtain the ZrO 2 @TiO 2 @PDMS dual-effect self-cleaning coating. The curing temperature is preferably 80°C - 120°C, and the curing time is preferably 1 - 6 h.

[0019] The superhydrophobic and photocatalytic properties of the double-effect self-cleaning coating of the present invention are excellent, and it has a wide range of applications in many fields such as the surfaces of building materials (including walls, glass, etc.), fabrics, and the outer shells of various equipment and tools. For example, by applying the method of the present invention to building materials, excellent physical and chemical self-cleaning functions can be achieved, which can well cope with problems such as the return of humidity in the south and the icing of walls in winter in the north, and has good moisture-proof and anti-condensation effects; by applying the coating of the present invention to the exterior coatings of cars, trains, and airplanes, residual water stains and stubborn oil stains can be prevented. In rainy and snowy weather, water droplets can quickly slide off and take away dust, without water stain residue, and has a good anti-icing effect; by applying the method of the present invention to clothing fabrics, waterproof and oil stain degradation effects can be achieved. At the same time, the porous structure of the coating will keep the clothes breathable to a certain extent, improve the comfort of people wearing, and has excellent flame retardant effects. By applying the coating of the present invention to the outer shells of electronic devices such as computers, mobile phones, and cameras, some common aqueous solutions in life such as milk, coffee, juice, and cola, and organic pollutants such as dyes and oils can be well isolated, which can improve the waterproof and anti-fouling functions of the devices.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] (1) The present invention uses ZrO 2 @TiO 2 to construct a micro-nano hierarchical structure. The coating has excellent superhydrophobic performance. When mixed with a fluorine-free low surface energy material PDMS and sprayed on various substrates, the water contact angle can reach more than 160°, and the rolling angle is as low as less than 2°. Water droplets can easily roll off the coating surface and will not stay on the surface, and can quickly clean inorganic dust, reflecting a good physical self-cleaning effect.

[0022] (2) The coating of the present invention has excellent photocatalytic performance and has a special porous structure, which can quickly adsorb organic pollutants such as dyes and oils and rapidly degrade them under the condition of light irradiation. After 100 minutes of simulated visible light irradiation, the degradation rate of rhodamine B dye solution is as high as 97.8%. After 5 cycles of use, the degradation rate still remains above 95%, reflecting an excellent chemical self-cleaning effect.

[0023] (3) The coating of the present invention uses a fluorine-free low surface energy modifier and environmentally friendly raw materials, and is pollution-free to the environment.

[0024] (4) The coating of the present invention has a wide range of applicable fields and has good effects in terms of mechanical wear resistance, flame retardancy, oil-water separation, moisture-proof, etc. Description of the Drawings

[0025] Figure 1 The scanning electron microscope image of the ZrO 2 @TiO 2 double-effect self-cleaning coating prepared in Example 1 under microscopic conditions.

[0026] Figure 2 0.1 g of ZrO prepared in Example 1 2 @TiO 2 Effect diagram of the degradation of 10 mL of rhodamine B dye solution with a concentration of 20 mg / L by the dual-functional self-cleaning coating under 6 h of natural light irradiation.

[0027] Figure 3 0.2 g of ZrO prepared in Example 1 2 @TiO 2 Comparison diagram of the degradation effect of the dual-functional self-cleaning coating and other photocatalysts on 10 mL of methylene blue dye solution with a concentration of 20 mg / L under 3 days of natural light irradiation. From left to right are ZrO 2 -TiO 2 -CeO 2 , UIO-66, commercially available ZrO 2 -TiO 2 , ZrO 2 @TiO 2 Dual-functional self-cleaning coating, TiO 2 .

[0028] Figure 4 Comparison diagram of the degradation effect of the dual-functional self-cleaning stainless steel mesh prepared in Example 5 and the coatings made of other photocatalysts on stainless steel mesh after irradiating with a 300 W xenon lamp for 100 min on 10 mL of rhodamine B dye solution with a concentration of 20 mg / L. From left to right, the photocatalysts in the coatings are UIO-66, TiO 2 , commercially available ZrO 2 -TiO 2 , ZrO 2 @TiO 2 Dual-functional self-cleaning coating.

[0029] Figure 5 UV-visible spectrum diagram of the degradation of 10 mL of rhodamine B dye solution with a concentration of 20 mg / L by the dual-functional self-cleaning stainless steel mesh prepared in Example 5 after irradiating with a 300 W xenon lamp for 0 - 100 min.

[0030] Figure 6 Chemical self-cleaning effect diagram of the dual-functional self-cleaning cotton fabric prepared in Example 2. The left and right pictures are the effect diagrams of water droplets on the coating after being infiltrated with 100 μL of oleic acid and after being irradiated with UV for 6 h, respectively.

[0031] Figure 7 Physical self-cleaning effect diagram of the dual-functional self-cleaning copper sheet prepared in Example 1. The left, middle, and right pictures are the photos before, during, and after dripping water, respectively.

[0032] Figure 8Flame retardancy effect diagram of the dual-functional self-cleaning cotton fabric prepared in Example 2. The group (a) of pictures shows the combustion process of the original cotton fabric, and the group (b) of pictures shows the combustion effect diagram of the dual-functional self-cleaning cotton fabric. The superhydrophobic effect of the ash after combustion is shown within the dashed box.

[0033] Figure 9 Moisture-proof effect diagram of the dual-functional self-cleaning glass slide prepared in Example 3. The left and right pictures are the moisture-proof effects of the original glass slide and the dual-functional self-cleaning glass slide respectively.

[0034] Figure 10 Moisture-proof effect diagram of the dual-functional self-cleaning alloy sheet prepared in Example 4. The left and right pictures are the moisture-proof effects of the original alloy sheet and the dual-functional self-cleaning alloy sheet respectively.

[0035] Figure 11 Oil-water separation effect diagram of the dual-functional self-cleaning stainless steel mesh prepared in Example 5. The pictures from left to right show the process and effect of oil-water separation.

[0036] Figure 12 Superhydrophobic effect diagram of water droplets on the surface of the dual-functional self-cleaning stainless steel mesh prepared in Example 5 after being scraped with a knife.

[0037] Figure 13 Schematic diagram of the dual-functional self-cleaning stainless steel prepared in Example 5 restoring superhydrophobic performance after degrading organic matter under light.

[0038] Figure 14 Optical photographs of water droplets on the surface of the dual-functional self-cleaning coatings prepared in Examples 1 - 5. Detailed implementation manners

[0039] The present invention will be further described in detail below in conjunction with the embodiments and the drawings, but the implementation manners of the present invention are not limited thereto. The raw materials involved in the present invention can be directly purchased from the market. For the process parameters not specifically noted, conventional techniques can be referred to.

[0040] The UIO-66 powder used in the following examples was prepared by the following method: Dissolve 1.15 g of zirconium chloride powder and 0.8 g of terephthalic acid powder in 75 mL of N,N-dimethylformamide, add 15 mL of acetic acid as a catalyst, ultrasonically process the suspension for 15 min, and stir it in a magnetic stirring table for 45 min. Then transfer it to a high-pressure hydrothermal autoclave and heat it in an oven at 130 °C for 24 h, take it out, cool it to room temperature, and centrifuge and dry it to obtain the UIO-66 powder.

[0041] Example 1

[0042] The preparation method of this example includes the following steps:

[0043] (1) Substrate treatment: The copper sheet was ultrasonically cleaned with deionized water, absolute ethanol, and acetone respectively. The size of the copper sheet was 3×3 cm 2 , and then dried for standby.

[0044] (2) Synthesis of UIO-66@TiO 2 : 7 mL of deionized water was mixed with 14 mL of absolute ethanol, and 5 mol / L nitric acid was added to adjust the pH to 2.6 to prepare solution A; 5 mL of glacial acetic acid, 10 mL of tetrabutyl titanate, and 30 mL of absolute ethanol were mixed, and then 27 g of UIO-66 powder with a solid content of 600 g / L was added to prepare suspension B; under strong stirring, solution A was dropped into suspension B at a rate of 2 drops / s. After dropping, the stirring was stopped and aged for 20 h to form a white colloid. Then it was transferred to a drying oven and dried to obtain UIO-66@TiO 2 powder.

[0045] (3) Preparation of ZrO 2 @TiO 2 coating: The UIO-66@TiO 2 powder prepared in step (2) was calcined in a muffle furnace at 420 °C for 2 h to obtain porous ZrO 2 @TiO 2 powder.

[0046] (4) Preparation of ZrO 2 @TiO 2 @PDMS coating: The ZrO 2 @TiO 2 with a solid content of 40 g / L prepared in step (3) and 40 g / L PDMS were dispersed in n-hexane and ultrasonically treated in a 200 W ultrasonic instrument for 30 min, and then sprayed onto the copper sheet and placed in a drying oven at 120 °C for curing for 1 h to obtain the ZrO 2 @TiO 2 @PDMS dual-functional self-cleaning coating.

[0047] Figure 1 shows the microscopic morphology of the ZrO 2 @TiO 2 dual-functional self-cleaning coating, proving that it has a porous micro-nano structure; Figure 2 shows the ability of the ZrO 2 @TiO 2 dual-functional self-cleaning coating to degrade rhodamine B dye solution, Figure 3 compares the ability of the ZrO 2 @TiO 2 dual-functional self-cleaning coating and other photocatalysts to degrade methyl blue dye solution, proving its ability to efficiently degrade various dyes; as Figure 14 shown, after measurement, ZrO2 @TiO 2 The water contact angle of the @PDMS dual-functional self-cleaning copper sheet is 162.7°, and the rolling angle is 1.8°, showing excellent superhydrophobic performance.

[0048] Example 2

[0049] The preparation method of this example includes the following steps:

[0050] (1) Substrate treatment: Ultrasonically clean the stainless steel mesh with deionized water, absolute ethanol, and acetone respectively. The size of the cotton fabric is 3×3 cm 2 , and dry it for later use.

[0051] (2) Synthesis of UIO-66@TiO 2 : Mix 10 mL of deionized water with 20 mL of absolute ethanol, add 5 mol / L nitric acid to adjust the pH to 3 to make solution A; mix 5 mL of glacial acetic acid, 10 mL of tetrabutyl titanate, and 30 mL of absolute ethanol, and then add UIO-66 with a solid content of 1000 g / L to make suspension B; under strong stirring, slowly add solution A to suspension B at a rate of 3 drops / s. After dropping, stop stirring and age for 24 h to form a white colloid. Then transfer it to an oven for drying to obtain UIO-66@TiO 2 powder.

[0052] (3) Preparation of ZrO 2 @TiO 2 coating: Put the UIO-66@TiO 2 powder prepared in step (2) into a muffle furnace and calcine it at 440 °C for 1 h to obtain porous ZrO 2 @TiO 2 powder.

[0053] (4) Preparation of ZrO 2 @TiO 2 @PDMS coating: Disperse the ZrO 2 @TiO 2 with a solid content of 70 g / L and 70 g / L PDMS in n-hexane and ultrasonicate them in a 200 W ultrasonic bath for 30 min. Then spray them onto the cotton fabric and cure it in an oven at 80 °C for 2 h to obtain the ZrO 2 @TiO 2 @PDMS dual-functional self-cleaning coating.

[0054] Figure 6 Shows the ability of the ZrO 2 @TiO 2 @PDMS dual-functional self-cleaning cotton fabric to degrade oleic acid, demonstrating its ability to degrade organic oils to a certain extent. Figure 8The flame retardancy of the original cotton fabric was compared with that of the ZrO 2 @TiO 2 @PDMS double-effect self-cleaning cotton fabric, and it was proved that the ZrO 2 @TiO 2 @PDMS double-effect self-cleaning cotton fabric has good flame retardant function. As Figure 14 shown, it was measured that the water contact angle of the ZrO 2 @TiO 2 @PDMS double-effect self-cleaning cotton fabric is 160.2°, and the rolling angle is 2°, showing excellent superhydrophobic performance.

[0055] Example 3

[0056] The preparation method of this example includes the following steps:

[0057] (1) Substrate treatment: The glass slide was ultrasonically cleaned with deionized water, absolute ethanol and acetone respectively. The size of the glass slide is 2.6×7.6 cm 2 , and dried for later use.

[0058] (2) Synthesis of UIO-66@TiO 2 : Mix 6 mL of deionized water and 12 mL of absolute ethanol, add 5 mol / L nitric acid to adjust the pH to 2.4 to make solution A; mix 5 mL of glacial acetic acid, 10 mL of tetrabutyl titanate and 30 mL of absolute ethanol, and then add UIO-66 with a solid content of 400 g / L to make suspension B; under strong stirring, add solution A dropwise to suspension B at a rate of 1 drop / s. After dropping, stop stirring and age for 16 h to form a white colloid. Then transfer it to an oven and dry to obtain UIO-66@TiO 2 powder.

[0059] (3) Preparation of ZrO 2 @TiO 2 coating: Put the UIO-66@TiO 2 powder prepared in step (2) into a muffle furnace and calcine at 410 °C for 2 h to obtain porous ZrO 2 @TiO 2 powder.

[0060] (4) Preparation of ZrO 2 @TiO 2 @PDMS coating: Disperse the ZrO 2 @TiO 2 with a solid content of 60 g / L and 60 g / L PDMS in n-hexane and ultrasonicate in a 200 W ultrasonic instrument for 30 min, then spray it onto the glass slide and put it into an oven to cure at 100 °C for 3 h to obtain ZrO 2 @TiO2 @PDMS dual-functional self-cleaning coating.

[0061] Figure 9 Shows ZrO 2 @TiO 2 @The moisture-proof ability of the PDMS dual-functional self-cleaning glass slide. The water contact angle of the uncoated glass slide is 73°, while that of the ZrO 2 @TiO 2 @The water contact angle of the PDMS dual-functional self-cleaning glass slide is 163°, and the rolling angle is 1.7°, proving that the coating can prevent water vapor from condensing on the surface and has excellent superhydrophobic performance.

[0062] Example 4

[0063] The preparation method of this example includes the following steps:

[0064] (1) Substrate treatment: Ultrasonically clean the alloy sheet with deionized water, absolute ethanol, and acetone respectively. The size of the alloy sheet is 2×3 cm 2 , and dry it for later use;

[0065] (2) Synthesis of UIO-66@TiO 2 : Mix 8 mL of deionized water with 16 mL of absolute ethanol, add 5 mol / L nitric acid to adjust the pH to 2.8 to make solution A; mix 5 mL of glacial acetic acid, 10 mL of tetrabutyl titanate, and 30 mL of absolute ethanol, and then add UIO-66 with a solid content of 800 g / L to make suspension B; under strong stirring, slowly drip solution A into suspension B at a rate of 2 drops / s. After dripping, stop stirring and age for 20 h to form a white colloid. Then transfer it to a drying oven and dry it to obtain UIO-66@TiO 2 powder.

[0066] (3) Preparation of ZrO 2 @TiO 2 coating: Put the UIO-66@TiO 2 powder prepared in step (2) into a muffle furnace and calcine it at 430 °C for 2 h to obtain porous ZrO 2 @TiO 2 powder.

[0067] (4) Preparation of ZrO 2 @TiO 2 @PDMS coating: Disperse the ZrO 2 @TiO 2 with a solid content of 30 g / L and 30 g / L of PDMS in n-hexane and ultrasonicate it in a 200 W ultrasonic instrument for 30 min, then spray it onto the alloy sheet and put it into a drying oven to cure at 120 °C for 1 h to obtain ZrO 2@TiO 2 @PDMS dual-effect self-cleaning coating.

[0068] Figure 10 Shows ZrO 2 @TiO 2 @PDMS dual-effect self-cleaning alloy sheet's moisture-proof ability. As Figure 14 shown, it is measured that ZrO 2 @TiO 2 @PDMS dual-effect self-cleaning alloy sheet has a water contact angle of 162.8° and a rolling angle of 1.8°, with excellent superhydrophobic performance.

[0069] Example 5

[0070] The preparation method of this example includes the following steps:

[0071] (1) Substrate treatment: Ultrasonically clean the stainless steel mesh with deionized water, absolute ethanol, and acetone respectively. The size of the stainless steel mesh is 3×3 cm 2 , and dry it for later use;

[0072] (2) Synthesis of UIO-66@TiO 2 : Mix 5 mL of deionized water with 10 mL of absolute ethanol, add 5 mol / L nitric acid to adjust the pH to 2.2 to make solution A; mix 5 mL of glacial acetic acid, 10 mL of tetrabutyl titanate, and 30 mL of absolute ethanol, and then add UIO-66 with a solid content of 200 g / L to make suspension B; under strong stirring, slowly add solution A to suspension B at a rate of 1 drop / s. After the addition, stop stirring and age for 12 h to form a white colloid. Then transfer it to an oven for drying to obtain UIO-66@TiO 2 powder.

[0073] (3) Preparation of ZrO 2 @TiO 2 coating: Put the UIO-66@TiO 2 powder prepared in step (2) into a muffle furnace and calcine it at 400 °C for 2 h to obtain porous ZrO 2 @TiO 2 powder.

[0074] (4) Preparation of ZrO 2 @TiO 2 @PDMS coating: Disperse the ZrO 2 @TiO 2 with a solid content of 50 g / L and 50 g / L PDMS in n-hexane and ultrasonicate it in a 200 W ultrasonic cleaner for 30 min, then spray it onto the stainless steel mesh and put it into an oven at 80 °C for curing for 4 h to obtain ZrO 2 @TiO2 @PDMS dual-effect self-cleaning coating.

[0075] Figure 4 Compared ZrO 2 @TiO 2 @PDMS dual-effect self-cleaning stainless steel mesh and the ability of coatings made of other photocatalysts on stainless steel mesh to degrade rhodamine B dye solution. Figure 5 Showed ZrO 2 @TiO 2 @PDMS dual-effect self-cleaning stainless steel mesh ultraviolet-visible spectrum diagram of degrading rhodamine B dye solution. After calculation, its degradation rate of rhodamine B dye solution is as high as 97.8% within 100 min. Figure 11 Showed ZrO 2 @TiO 2 @PDMS dual-effect self-cleaning stainless steel mesh's oil-water separation ability. After calculation, its flux of chloroform is as high as 40,000 L·h-1m-2, and the separation efficiency is as high as 98%. Figure 7 Showed that water droplets can smoothly carry away CuSO 4 particles on the coating at a 15° tilt angle, demonstrating a good physical self-cleaning effect. Figure 12 Proved ZrO 2 @TiO 2 @PDMS dual-effect self-cleaning stainless steel mesh has excellent mechanical durability. Figure 13 For ZrO 2 @TiO 2 @PDMS dual-effect self-cleaning stainless steel mesh schematic diagram of restoring superhydrophobic performance after degrading organic matter under light. As Figure 14 shown, after measurement, the water contact angle of ZrO 2 @TiO 2 @PDMS dual-effect self-cleaning stainless steel mesh is 162.5°, and the rolling angle is 1.7°, with excellent superhydrophobic performance.

[0076] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a porous dual-effect self-cleaning coating, characterized in that: The steps include: (1) Synthesis of UIO-66@TiO2: Mix water and ethanol, add acid to adjust the pH to 1.0-4.0, and prepare solution A; mix glacial acetic acid, tetrabutyl titanate, and anhydrous ethanol, and then add UIO-66 powder to prepare suspension B; under strong stirring, slowly add solution A to suspension B, stop stirring after the addition, let stand until a white colloid is formed, and then dry to obtain UIO-66@TiO2 powder; (2) Preparation of ZrO2@TiO2 powder: calcining the UIO-66@TiO2 powder prepared in step (1) at 300°C-500°C for 0.5-3h to obtain porous ZrO2@TiO2 powder; (3) Preparation of ZrO2@TiO2@PDMS coating: The ZrO2@TiO2 powder and PDMS prepared in step (2) are dispersed in n-hexane and subjected to ultrasonic treatment to obtain a porous dual-effect self-cleaning coating.

2. The preparation method according to claim 1, characterized in that: The volume ratio of water to ethanol in the solution A of step (1) is 1:1 to 1:3; the volume ratio of glacial acetic acid, TBT and anhydrous ethanol in the suspension B is 1:2±1:6±2.

3. The preparation method according to claim 2, characterized in that: The solid content of UIO-66 in the suspension B in step (1) is 100 to 1000 g / L.

4. The preparation method according to claim 3, characterized in that: The mass ratio of the ZrO2@TiO2 powder to PDMS in step (3) is 1:(0.5-3).

5. The preparation method according to claim 4, characterized in that: In step (3), the mass volume ratio of the ZrO2@TiO2 powder to n-hexane is 10-100 g / L, and the mass volume ratio of PDMS to n-hexane is 10-100 g / L; the ultrasound is performed at a power of 200±50 W for 30-60 min.

6. The preparation method according to any one of claims 1 to 5, characterized in that: In step (2), the calcination temperature is 380° C. to 450° C., and the calcination time is 90 to 150 minutes.

7. The preparation method according to claim 6, characterized in that: The pH in step (1) is 2 to 3, and the standing time is 12 to 24 hours.

8. The preparation method according to claim 7, characterized in that: Step (1) Synthesis of UIO-66 powder: Dissolve zirconium chloride powder and terephthalic acid powder in N,N-dimethylformamide, add acetic acid as a catalyst, ultrasonically treat the suspension, stir, and then heat at 130±20°C for 6 to 48 hours, cool, and centrifuge to obtain UIO-66 powder.

9. The porous dual-effect self-cleaning coating prepared by the preparation method according to any one of claims 1 to 8.

10. A porous dual-effect self-cleaning coating, characterized in that: The coating according to claim 9 is sprayed onto a substrate and cured to obtain a ZrO2@TiO2@PDMS dual-effect self-cleaning coating.

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