A porous dual-effect self-cleaning coating and a method for preparing the same

Abstract

The application 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 and ethanol, adding acid to adjust the pH to 1.0-4.0 to prepare solution A; mixing glacial acetic acid, tetrabutyl titanate and anhydrous ethanol, and then adding UIO-66 powder to prepare suspension B; slowly adding solution A into suspension B under strong stirring, stopping stirring after the addition is completed, and standing until a white colloid is formed, and then drying to obtain UIO-66@TiO2 powder; (2) calcining the UIO-66@TiO2 powder at 300-500 DEG C for 0.5-3h to obtain porous ZrO2@TiO2 powder; (3) dispersing the ZrO2@TiO2 powder and PDMS in n-hexane and performing ultrasonic treatment to obtain the porous double-effect self-cleaning coating. The coating has excellent self-cleaning effect and excellent photocatalytic performance.

Description

Technical Field

[0001] This invention belongs to the field of self-cleaning coatings, specifically relating to the preparation and application of a porous dual-effect self-cleaning coating. Background Technology

[0002] Superhydrophobic coatings mimic the "lotus effect," employing micro / nano structures and low surface energy material modification to imbue the coating with superhydrophobicity, allowing water droplets to roll off and carry away surface dust, thus achieving physical self-cleaning. However, in practical applications, organic contaminants such as grease and dyes easily adhere to the coating surface and are difficult to remove with water, leading to the destruction of the coating's hydrophobic structure, a gradual decrease in hydrophobicity, and ultimately the loss of its superhydrophobic self-cleaning properties. Therefore, photocatalysts can be added to the coating to address this problem. The porosity and photocatalytic activity of the nanomaterial structure adsorb and catalyze organic contaminants, causing them to decompose into small molecules such as carbon dioxide and water under light, restoring the original superhydrophobicity and achieving chemical self-cleaning. In this way, water droplets can roll off inorganic matter, while light can degrade organic matter, achieving a dual self-cleaning effect. Dual-effect self-cleaning coatings can be applied to antifouling coatings through various micro-nano processes such as spraying, dip coating, spin coating, and vapor deposition. They are widely applicable to various fields such as textiles, building materials, transportation, and energy and chemical industries, and show broad application prospects in many areas such as durability, flame retardancy, moisture resistance, and oil-water separation.

[0003] Currently, research on dual-effect self-cleaning coatings is limited, and key technical challenges remain: First, semiconductor photocatalysts such as TiO2 generate electron-hole pairs under light irradiation, reacting with adsorbed water and oxygen on the surface to produce active free radicals. Due to the electronic and inductive effects of fluorinated low surface energy materials, these active free radicals are more likely to attack hydrophobic groups, causing their chemical bonds to break and thus losing their superhydrophobic properties. Second, compared to the direct hydrophobic and oleophobic effects of traditional fluorinated superhydrophobic coatings, the photocatalytic degradation of organic pollutants by dual-effect self-cleaning coatings is too slow, often requiring a significant amount 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 key research focuses for dual-effect self-cleaning coatings. Summary of the Invention

[0004] The purpose of this invention is to provide a porous dual-effect self-cleaning coating and its application. This coating is prepared by co-sintering TiO2 and UIO-66 (Zr) at a certain temperature to obtain a porous ZrO2@TiO2 heterojunction micro / nano-scale photocatalyst. Then, it is mixed with PDMS in a certain proportion and finally sprayed onto the surface of various substrates to achieve a superhydrophobic effect with a contact angle >160° and a roll-off angle <2°. Furthermore, the coating exhibits a 97.8% degradation rate of Rhodamine B after 100 minutes of light irradiation, and demonstrates good mechanical wear resistance, flame retardancy, moisture resistance, and oil-water separation properties.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for preparing a porous dual-effect self-cleaning coating includes the following steps:

[0007] (1) Synthesis of UIO-66@TiO2: Water and ethanol were mixed, and the pH was adjusted to 1.0-4.0 with acid to prepare solution A; glacial acetic acid, tetrabutyl titanate and anhydrous ethanol were mixed, and then UIO-66 powder was added to prepare suspension B; under strong stirring, solution A was slowly added dropwise to suspension B. After the addition was complete, stirring was stopped, and the mixture was allowed to stand until a white colloid was formed. Then it was dried to obtain UIO-66@TiO2 powder.

[0008] (2) Preparation of ZrO2@TiO2 powder: The UIO-66@TiO2 powder prepared in step (1) was calcined at 300℃-500℃ for 0.5-3h to obtain porous ZrO2@TiO2 powder;

[0009] (3) Preparation of ZrO2@TiO2@PDMS coating: The ZrO2@TiO2 powder obtained in step (2) is dispersed with PDMS in n-hexane solution and subjected to ultrasonic treatment to obtain a porous dual-effect self-cleaning coating.

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

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

[0012] Preferably, the mass ratio of ZrO2@TiO2 powder to PDMS in step (3) is 1:(0.5-3).

[0013] Preferably, in step (3), the mass-to-volume ratio of ZrO2@TiO2 powder to n-hexane is 10-100 g / L, and the mass-to-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.

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

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

[0016] Preferably, in step (1) the synthesis of UIO-66 powder: zirconium chloride powder and terephthalic acid powder are dissolved in N,N-dimethylformamide, acetic acid is added as a catalyst, the suspension is placed in a 200±50W ultrasonic instrument and sonicated for 30 to 60 minutes, stirred for 30 minutes to 1 hour, then heated at 130±20℃ for 6 to 48 hours, cooled, and centrifuged and dried to obtain UIO-66 powder.

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

[0018] A porous, dual-effect self-cleaning coating is obtained by spraying the coating onto a substrate and then curing it, resulting in a ZrO2@TiO2@PDMS dual-effect self-cleaning coating. The preferred curing temperature is 80℃~120℃, and the preferred curing time is 1~6 hours.

[0019] The dual-effect self-cleaning coating of this invention exhibits excellent superhydrophobic and photocatalytic properties, and has wide applications in various fields, including building material surfaces (including walls, glass, etc.), fabrics, and the casings of various equipment and tools. For example, when used on building materials, the method of this invention achieves excellent physical and chemical self-cleaning functions, effectively addressing issues such as the humid weather in the south and wall icing in northern winters, providing excellent moisture-proof and anti-condensation effects. When used on the exterior coatings of automobiles, trains, and airplanes, this invention prevents residual water stains and stubborn oil stains. In rainy or snowy weather, water droplets quickly slide off, carrying away dust without leaving water stains, and it also has excellent anti-icing effects. When used on clothing fabrics, this invention achieves waterproofing and oil stain degradation. Simultaneously, the porous structure of the coating allows clothing to maintain a certain degree of breathability, improving wearing comfort, and also provides excellent flame retardant properties. When used on the casings of electronic devices such as computers, mobile phones, and cameras, this invention effectively isolates common aqueous solutions such as milk, coffee, juice, and cola, as well as organic pollutants such as dyes and greases, improving the waterproof and stain-resistant 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 ZrO2@TiO2 to construct a micro-nano hierarchical structure. The coating has excellent superhydrophobic properties. When mixed with fluorine-free low surface energy material PDMS and sprayed on various substrates, the water droplet contact angle can reach more than 160° and the roll-off angle is as low as less than 2°. Water droplets can easily roll off the coating surface and will not remain on the surface. It can also quickly clean inorganic dust, demonstrating a good physical self-cleaning effect.

[0022] (2) The coating of the present invention has excellent photocatalytic performance and a special porous structure, which can rapidly adsorb organic pollutants such as dyes and oils and degrade them rapidly under light irradiation. After 100 minutes of simulated visible light irradiation, the degradation rate of Rhodamine B dye solution is as high as 97.8%, and after 5 cycles of use, it still maintains a degradation rate of more than 95%, demonstrating 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, which does not pollute the environment.

[0024] (4) The coating of the present invention has a wide range of applications and has good effects in mechanical wear resistance, flame retardancy, oil-water separation and moisture protection. Attached Figure Description

[0025] Figure 1 This is a scanning electron microscope image of the ZrO2@TiO2 dual-effect self-cleaning coating prepared in Example 1.

[0026] Figure 2 The image shows the effect of 0.1g ZrO2@TiO2 dual-effect self-cleaning coating prepared in Example 1 degrading 10mL of 20mg / L Rhodamine B dye solution after 6 hours of natural light irradiation.

[0027] Figure 3 This is a comparison chart showing the effect of 0.2g of ZrO2@TiO2 dual-effect self-cleaning coating prepared in Example 1 on the degradation of 10mL of 20mg / L methylene blue dye solution by other photocatalysts after 3 days of natural light irradiation. From left to right, they are ZrO2-TiO2-CeO2, UIO-66, commercially available ZrO2-TiO2, ZrO2@TiO2 dual-effect self-cleaning coating, and TiO2.

[0028] Figure 4 This image shows a comparison of the degradation effects of the dual-effect self-cleaning stainless steel mesh prepared in Example 5 and other photocatalysts on the stainless steel mesh after irradiation with a 300W xenon lamp for 100 minutes on 10 mL of 20 mg / L Rhodamine B dye solution. From left to right, the photocatalysts in the coatings are UIO-66, TiO2, commercially available ZrO2-TiO2, and ZrO2@TiO2 dual-effect self-cleaning coating, respectively.

[0029] Figure 5 The UV-Vis spectrum of the double-effect self-cleaning stainless steel mesh prepared in Example 5 after being irradiated by a 300W xenon lamp for 0-100 min and degrading 10 mL of 20 mg / L Rhodamine B dye solution.

[0030] Figure 6The images show the chemical self-cleaning effect of the dual-effect self-cleaning cotton fabric prepared in Example 2. The left and right images are the effects of water droplets on the coating after immersion in 100 μL of oleic acid and after UV irradiation for 6 hours, respectively.

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

[0032] Figure 8 The images show the flame retardant effect of the dual-effect self-cleaning cotton fabric prepared in Example 2. (a) shows the burning process of the original cotton fabric, and (b) shows the burning effect of the dual-effect self-cleaning cotton fabric. The superhydrophobic effect of the ash after burning is shown in the dashed box.

[0033] Figure 9 The images show the moisture-proof effect of the dual-effect self-cleaning glass slide prepared in Example 3. The left and right images show the moisture-proof effect of the original glass slide and the moisture-proof effect of the dual-effect self-cleaning glass slide, respectively.

[0034] Figure 10 The images show the moisture-proof effect of the dual-effect self-cleaning alloy sheet prepared in Example 4. The left and right images show the moisture-proof effect of the original alloy sheet and the moisture-proof effect of the dual-effect self-cleaning alloy sheet, respectively.

[0035] Figure 11 The images show the oil-water separation effect of the double-effect self-cleaning stainless steel mesh prepared in Example 5. The images from left to right illustrate the oil-water separation process and effect.

[0036] Figure 12 This image shows the superhydrophobic effect of water droplets on the surface of the dual-effect self-cleaning stainless steel mesh prepared in Example 5 after it has been scraped with a knife.

[0037] Figure 13 This is a schematic diagram showing the restoration of superhydrophobic properties of the dual-effect self-cleaning stainless steel prepared in Example 5 after the degradation of organic matter under light.

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

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

[0040] The UIO-66 powder used in the following examples was prepared by the following method: 1.15 g of zirconium chloride powder and 0.8 g of terephthalic acid powder were dissolved in 75 mL of N,N-dimethylformamide, 15 mL of acetic acid was added as a catalyst, the suspension was sonicated for 15 min, stirred in a magnetic stirrer for 45 min, transferred to an autoclave and heated in a drying oven at 130 °C for 24 h, then removed, cooled to room temperature, and centrifuged to dry to obtain UIO-66 powder.

[0041] Example 1

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

[0043] (1) Substrate treatment: The copper sheet was ultrasonically cleaned with deionized water, anhydrous ethanol and acetone respectively. The copper sheet size was 3×3cm. 2 Dry and set aside for later use.

[0044] (2) Synthesis of UIO-66@TiO2: 7 mL of deionized water and 14 mL of anhydrous ethanol were mixed, and the pH was adjusted to 2.6 with 5 mol / L nitric acid to prepare solution A. 5 mL of glacial acetic acid, 10 mL of tetrabutyl titanate, and 30 mL of anhydrous ethanol were mixed, and 27 g of UIO-66 powder was added. The solid content of UIO-66 was 600 g / L, forming suspension B. Under vigorous stirring, solution A was added dropwise to suspension B at a rate of 2 drops / s. After the addition was complete, stirring was stopped, and the mixture was aged for 20 h to form a white colloid. Then, it was transferred to a drying oven and dried to obtain UIO-66@TiO2 powder.

[0045] (3) Preparation of ZrO2@TiO2 coating: The UIO-66@TiO2 powder prepared in step (2) was placed in a muffle furnace and calcined at 420°C for 2 hours to obtain porous ZrO2@TiO2 powder.

[0046] (4) Preparation of ZrO2@TiO2@PDMS coating: The ZrO2@TiO2 with a solid content of 40g / L obtained in step (3) and 40g / L PDMS are dispersed in n-hexane and sonicated in a 200W ultrasonic instrument for 30min. Then, it is sprayed onto a copper sheet and placed in a drying oven at 120℃ for 1h to obtain a ZrO2@TiO2@PDMS dual-effect self-cleaning coating.

[0047] Figure 1 The microstructure of the ZrO2@TiO2 dual-effect self-cleaning coating was shown, proving that it has a porous micro-nano structure; Figure 2 The ZrO2@TiO2 dual-effect self-cleaning coating demonstrated its ability to degrade Rhodamine B dye liquor. Figure 3The ability of ZrO2@TiO2 dual-effect self-cleaning coating to degrade methylene blue dye solution was compared with that of other photocatalysts, demonstrating its ability to efficiently degrade various dyes; such as Figure 14 As shown, the ZrO2@TiO2@PDMS dual-effect self-cleaning copper sheet has a water contact angle of 162.7° and a roll-off angle of 1.8°, demonstrating excellent superhydrophobic properties.

[0048] Example 2

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

[0050] (1) Substrate treatment: The stainless steel mesh was ultrasonically cleaned with deionized water, anhydrous ethanol and acetone respectively. The cotton fabric size was 3×3cm. 2 Dry and set aside for later use.

[0051] (2) Synthesis of UIO-66@TiO2: 10 mL of deionized water and 20 mL of anhydrous ethanol were mixed, and 5 mol / L nitric acid was added to adjust the pH to 3 to prepare solution A. 5 mL of glacial acetic acid, 10 mL of tetrabutyl titanate, and 30 mL of anhydrous ethanol were mixed, and then UIO-66 with a solid content of 1000 g / L was added to prepare suspension B. Under vigorous stirring, solution A was added dropwise to suspension B at a rate of 3 drops / s. After the addition was complete, stirring was stopped, and the mixture was aged for 24 h to form a white colloid. Then, it was transferred to a drying oven and dried to obtain UIO-66@TiO2 powder.

[0052] (3) Preparation of ZrO2@TiO2 coating: The UIO-66@TiO2 powder prepared in step (2) was placed in a muffle furnace and calcined at 440°C for 1 h to obtain porous ZrO2@TiO2 powder.

[0053] (4) Preparation of ZrO2@TiO2@PDMS coating: The ZrO2@TiO2 with a solid content of 70g / L obtained in step (3) and 70g / L PDMS are dispersed in n-hexane and ultrasonicated in a 200W ultrasonic instrument for 30min. Then, it is sprayed onto cotton fabric and placed in a drying oven at 80℃ for 2h to obtain ZrO2@TiO2@PDMS dual-effect self-cleaning coating.

[0054] Figure 6 The ability of ZrO2@TiO2@PDMS dual-effect self-cleaning cotton fabric to degrade oleic acid was demonstrated, proving that it has a certain ability to degrade organic oils. Figure 8 The flame retardant properties of the original cotton fabric and the ZrO2@TiO2@PDMS dual-effect self-cleaning cotton fabric were compared, demonstrating that the ZrO2@TiO2@PDMS dual-effect self-cleaning cotton fabric has good flame retardant properties. Figure 14As shown, the ZrO2@TiO2@PDMS dual-effect self-cleaning cotton fabric has a water contact angle of 160.2° and a roll-off angle of 2°, exhibiting excellent superhydrophobic properties.

[0055] Example 3

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

[0057] (1) Substrate treatment: The glass slides were ultrasonically cleaned with deionized water, anhydrous ethanol, and acetone, respectively. The size of the glass slides was 2.6 × 7.6 cm. 2 Dry and set aside for later use.

[0058] (2) Synthesis of UIO-66@TiO2: 6 mL of deionized water and 12 mL of anhydrous ethanol were mixed, and 5 mol / L nitric acid was added to adjust the pH to 2.4 to prepare solution A. 5 mL of glacial acetic acid, 10 mL of tetrabutyl titanate, and 30 mL of anhydrous ethanol were mixed, and then UIO-66 with a solid content of 400 g / L was added to prepare suspension B. Under vigorous stirring, solution A was added dropwise to suspension B at a rate of 1 drop / s. After the addition was complete, stirring was stopped, and the mixture was aged for 16 h to form a white colloid. Then, it was transferred to a drying oven and dried to obtain UIO-66@TiO2 powder.

[0059] (3) Preparation of ZrO2@TiO2 coating: The UIO-66@TiO2 powder prepared in step (2) was placed in a muffle furnace and calcined at 410°C for 2 hours to obtain porous ZrO2@TiO2 powder.

[0060] (4) Preparation of ZrO2@TiO2@PDMS coating: The ZrO2@TiO2 with a solid content of 60g / L obtained in step (3) and 60g / L PDMS are dispersed in n-hexane and sonicated in a 200W ultrasonic instrument for 30min. Then, it is sprayed onto a glass slide and placed in a drying oven at 100℃ for 3h to obtain the ZrO2@TiO2@PDMS dual-effect self-cleaning coating.

[0061] Figure 9 The moisture-proof capability of ZrO2@TiO2@PDMS dual-effect self-cleaning glass slides was demonstrated. The water contact angle of the uncoated glass slide was 73°, while that of the ZrO2@TiO2@PDMS dual-effect self-cleaning glass slide was 163° and the roll-off angle was 1.7°, proving that the coating can prevent water vapor from condensing on the surface and has excellent superhydrophobic properties.

[0062] Example 4

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

[0064] (1) Substrate treatment: The alloy sheet was ultrasonically cleaned with deionized water, anhydrous ethanol and acetone respectively. The alloy sheet size was 2×3cm. 2 Dry and set aside for later use;

[0065] (2) Synthesis of UIO-66@TiO2: 8 mL of deionized water and 16 mL of anhydrous ethanol were mixed, and the pH was adjusted to 2.8 with 5 mol / L nitric acid to prepare solution A. 5 mL of glacial acetic acid, 10 mL of tetrabutyl titanate, and 30 mL of anhydrous ethanol were mixed, and then UIO-66 with a solid content of 800 g / L was added to prepare suspension B. Under vigorous stirring, solution A was added dropwise to suspension B at a rate of 2 drops / s. After the addition was complete, stirring was stopped, and the mixture was aged for 20 h to form a white colloid. Then, it was transferred to a drying oven and dried to obtain UIO-66@TiO2 powder.

[0066] (3) Preparation of ZrO2@TiO2 coating: The UIO-66@TiO2 powder prepared in step (2) was placed in a muffle furnace and calcined at 430°C for 2 hours to obtain porous ZrO2@TiO2 powder.

[0067] (4) Preparation of ZrO2@TiO2@PDMS coating: The ZrO2@TiO2 with a solid content of 30g / L obtained in step (3) and 30g / L PDMS are dispersed in n-hexane and sonicated in a 200W ultrasonic instrument for 30min. Then, it is sprayed onto the alloy sheet and placed in a drying oven at 120℃ for 1h to obtain the ZrO2@TiO2@PDMS dual-effect self-cleaning coating.

[0068] Figure 10 The moisture-proof capability of the ZrO2@TiO2@PDMS dual-effect self-cleaning alloy sheet was demonstrated. For example... Figure 14 As shown, the ZrO2@TiO2@PDMS dual-effect self-cleaning alloy sheet has a water contact angle of 162.8° and a roll-off angle of 1.8°, exhibiting excellent superhydrophobic properties.

[0069] Example 5

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

[0071] (1) Substrate treatment: The stainless steel mesh was ultrasonically cleaned with deionized water, anhydrous ethanol and acetone respectively. The stainless steel mesh size was 3×3cm. 2 Dry and set aside for later use;

[0072] (2) Synthesis of UIO-66@TiO2: 5 mL of deionized water and 10 mL of anhydrous ethanol were mixed, and the pH was adjusted to 2.2 with 5 mol / L nitric acid to prepare solution A. 5 mL of glacial acetic acid, 10 mL of tetrabutyl titanate, and 30 mL of anhydrous ethanol were mixed, and then UIO-66 with a solid content of 200 g / L was added to prepare suspension B. Under vigorous stirring, solution A was added dropwise to suspension B at a rate of 1 drop / s. After the addition was complete, stirring was stopped, and the mixture was aged for 12 h to form a white colloid. Then, it was transferred to a drying oven and dried to obtain UIO-66@TiO2 powder.

[0073] (3) Preparation of ZrO2@TiO2 coating: The UIO-66@TiO2 powder prepared in step (2) was placed in a muffle furnace and calcined at 400°C for 2 hours to obtain porous ZrO2@TiO2 powder.

[0074] (4) Preparation of ZrO2@TiO2@PDMS coating: The ZrO2@TiO2 with a solid content of 50g / L obtained in step (3) and PDMS with a solid content of 50g / L are dispersed in n-hexane and ultrasonicated in a 200W ultrasonic instrument for 30min. Then, it is sprayed onto a stainless steel mesh and placed in a drying oven at 80℃ for 4h to obtain a ZrO2@TiO2@PDMS dual-effect self-cleaning coating.

[0075] Figure 4 The ability of ZrO2@TiO2@PDMS dual-effect self-cleaning stainless steel mesh to degrade Rhodamine B dye liquor was compared with that of other photocatalysts coated on stainless steel mesh. Figure 5 The UV-Vis spectrum of Rhodamine B dye solution degradation by ZrO2@TiO2@PDMS dual-effect self-cleaning stainless steel mesh is shown. Calculations show that it achieves a degradation rate of up to 97.8% for Rhodamine B dye solution within 100 minutes. Figure 11 The oil-water separation capability of the ZrO2@TiO2@PDMS dual-effect self-cleaning stainless steel mesh was demonstrated. Calculations show that it can handle a flow rate of up to 40,000 L·h⁻¹m⁻² for chloroform, with a separation efficiency of up to 98%. Figure 7 The results show that water droplets at a 15° tilt angle can effectively remove CuSO4 particles from the coating, demonstrating a good physical self-cleaning effect. Figure 12 The results demonstrate that the ZrO2@TiO2@PDMS dual-effect self-cleaning stainless steel mesh possesses excellent mechanical durability. Figure 13 This is a schematic diagram illustrating the restoration of superhydrophobic properties of a ZrO2@TiO2@PDMS dual-effect self-cleaning stainless steel mesh after the degradation of organic matter under light. Figure 14 As shown, the water contact angle of the ZrO2@TiO2@PDMS double-effect self-cleaning stainless steel mesh is 162.5° and the roll-off angle is 1.7°, demonstrating excellent superhydrophobic properties.

[0076] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should 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, Includes the following steps: (1) Synthesis of UIO-66@TiO2: Water and ethanol were mixed, and the pH was adjusted to 1.0-4.0 with acid to prepare solution A; glacial acetic acid, tetrabutyl titanate and anhydrous ethanol were mixed, and then UIO-66 powder was added to prepare suspension B; under strong stirring, solution A was slowly added dropwise to suspension B. After the addition was complete, stirring was stopped, and the mixture was allowed to stand until a white colloid was formed. Then it was dried to obtain UIO-66@TiO2 powder. (2) Preparation of ZrO2@TiO2 powder: The UIO-66@TiO2 powder prepared in step (1) was calcined at 300℃-500℃ for 0.5-3h to obtain porous ZrO2@TiO2 powder; (3) Preparation of ZrO2@TiO2@PDMS coating: The ZrO2@TiO2 powder obtained in step (2) is dispersed with PDMS 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, In step (1), the volume ratio of water to ethanol in solution A is 1:1 to 1:3; the volume ratio of glacial acetic acid, TBT and anhydrous ethanol in 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 100-1000 g / L.

4. The preparation method according to claim 3, characterized in that, The mass ratio of 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-to-volume ratio of ZrO2@TiO2 powder to n-hexane is 10-100 g / L, and the mass-to-volume ratio of PDMS to n-hexane is 10-100 g / L; the ultrasound is performed at a power of 200±50W 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℃~450℃ and the calcination time is 90~150min.

7. The preparation method according to claim 6, characterized in that, The pH value mentioned 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: Zirconium chloride powder and terephthalic acid powder are dissolved in N,N-dimethylformamide, acetic acid is added as a catalyst, the suspension is ultrasonically treated, stirred, and then heated at 130±20℃ for 6~48h. After cooling, the powder is centrifuged and dried 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 described in claim 9 is sprayed onto the substrate and cured to obtain a ZrO2@TiO2@PDMS dual-effect self-cleaning coating.

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