A method for preparing a super-hydrophobic wave-absorbing textile based on Zn-MOF derived carbon

Abstract

The application relates to a preparation method of a Zn-MOF derivative carbon-based super-hydrophobic wave-absorbing textile, which is prepared by immersing the textile in a mixed solution of silicone and Zn-MOF derivative carbon, and then sequentially performing padding, pre-drying and baking to obtain the Zn-MOF derivative carbon-based super-hydrophobic wave-absorbing textile; the silicone is hexadecyl trimethoxysilane, gamma-methacryloyloxypropyl trimethoxysilane, polydimethylsiloxane or polydimethylhydroxysiloxane; the Zn-MOF derivative carbon has a regular polyhedral structure and a diameter of 50-500 nm; the minimum reflection loss of the Zn-MOF derivative carbon is-20 to-50 dB; the water contact angle of the Zn-MOF derivative carbon-based super-hydrophobic wave-absorbing textile is not lower than 150.7 degrees, and the minimum reflection loss is not higher than-21.2 dB; the preparation method is simple, and the prepared product has super-hydrophobic and wave-absorbing properties.

Description

Technical Field

[0001] This invention belongs to the field of functional finishing technology of textiles, and relates to a method for preparing superhydrophobic microwave absorbing textiles based on Zn-MOF-derived carbon. Background Technology

[0002] Since breakthroughs in wireless communication technology, numerous new wireless connectivity devices have emerged, improving our quality of life but inevitably leading to severe electromagnetic (EM) pollution. Compared to ordinary electromagnetic shielding materials, absorbing materials avoid secondary pollution caused by electromagnetic waves reflected into the environment. Therefore, the development of electromagnetic wave absorbing materials provides a solution to this problem. Electromagnetic wave absorbing materials are widely used indoors, outdoors, and in electronic components, and are typically affected by various harsh environmental conditions (such as humidity, acidity, and alkalinity) in practical applications. Imparting superhydrophobic properties to electromagnetic wave absorbing materials enables excellent self-cleaning and anti-fouling properties, significantly extending their lifespan and effectiveness. Therefore, developing multifunctional superhydrophobic electromagnetic wave absorbing materials is of significant practical importance for improving the lifespan and absorption performance stability of electronic devices in harsh environments.

[0003] Currently, my country's textile industry is at a critical stage of transformation and upgrading. Accelerating the application of multifunctional finishing technology for textiles is one of the key projects of textile science and technology innovation in my country's textile industry development plan. Superhydrophobic and microwave-absorbing multifunctional textiles can effectively repel water and also dissipate most of the electromagnetic waves impacting their surface. These electromagnetic waves are reflected multiple times within the fabric and converted into heat for dissipation, protecting the human body from the harmful effects of external electromagnetic waves. They have multiple functions such as anti-fouling, self-cleaning, and microwave absorption, which can greatly extend the service life of microwave-absorbing textiles. At the same time, they possess the excellent properties of textile materials such as flexibility, breathability, and lightweight, and can be widely used in military tents, ship masts, microwave-absorbing protective clothing, etc. They have broad application prospects in industrial production, biomedicine, military protection, and daily life, and can also be extended to environmental engineering, building decoration materials, and other fields.

[0004] Currently, there are relatively few reported studies on multifunctional textiles that simultaneously possess superhydrophobic and wave-absorbing properties.

[0005] Chinese patent CN 115319080A discloses a method for preparing a superhydrophobic microwave absorbing material, the superhydrophobic microwave absorbing material prepared by this method, and its applications. A precursor solution is prepared by thoroughly mixing a boron-nitrogen source, a cobalt source, and deionized water. This precursor solution is evaporated at 50-80℃ until it becomes viscous, obtaining a pyrolytic precursor. The pyrolytic precursor is then calcined under an ammonia atmosphere and naturally cooled to obtain a brown, fluffy powder. Finally, the obtained black powder is washed with ethanol and vacuum dried to obtain the superhydrophobic microwave absorbing material. This patent requires a relatively long time to prepare the microwave absorbing material. Furthermore, although this patent explores the preparation and application of superhydrophobic microwave absorbing materials, it describes the material as a coating applied to the surface of a workpiece, without mentioning its application to textile surfaces.

[0006] Reference 1 (Electromagnetic absorber converting radiation for multifunction, Materials Science and Engineering:R:Reports, Volume 145, July 2021, 100627) explored flexible wearable electromagnetic wave absorbing materials. However, these materials lack excellent superhydrophobicity, cannot prevent the adhesion of pollutants, and may be susceptible to corrosion damage.

[0007] Reference 2 (Morphology-controlled CoNi / C hybrids with bifunctions of efficient anti-corrosion and microwave absorption, Journal of Materials Science & Technology, Volume 102, 10 March 2022, Pages 24-35) explored bifunctional materials with efficient anti-corrosion and microwave absorption by preparing three different morphologies of CoNi / C hybrids. The prepared materials had a water contact angle of 110.9°, which did not achieve superhydrophobicity and therefore could not provide excellent anti-corrosion function.

[0008] Therefore, it is of great significance to study a method for preparing a flexible microwave absorbing textile with good superhydrophobicity. Summary of the Invention

[0009] The purpose of this invention is to solve the above-mentioned problems in the prior art and provide a method for preparing superhydrophobic microwave absorbing textiles based on Zn-MOF-derived carbon.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A method for preparing superhydrophobic microwave absorbing textiles based on Zn-MOF (zinc metal-based organic framework) derived carbon involves immersing the textile in a mixed solution of organosilicon and Zn-MOF derived carbon, followed by padding, pre-drying, and baking to obtain the superhydrophobic microwave absorbing textile based on Zn-MOF derived carbon.

[0012] The organosilicon is hexadecyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, polydimethylsiloxane or polydimethylhydroxysiloxane. The organosilicon suitable for the present invention includes, but is not limited to, the above-mentioned ones. Other low surface energy organosilicones with adhesive properties are also suitable for the present invention.

[0013] Zn-MOF-derived carbon has a regular polyhedral structure with a diameter of 50–500 nm, providing micro- and nano-rough structures for textiles; the minimum reflection loss of Zn-MOF-derived carbon is -20 to -50 dB.

[0014] The water contact angle of the superhydrophobic absorbing textile based on Zn-MOF-derived carbon is no less than 150.7° and the minimum reflection loss is no higher than -21.2dB.

[0015] As a preferred technical solution:

[0016] The method for preparing a superhydrophobic microwave absorbing textile based on Zn-MOF-derived carbon as described above involves a mixed solution of organosilicon and Zn-MOF-derived carbon, in which the solvent is isopropanol, n-hexane, benzyl alcohol, acetone, N,N-dimethylformamide or ethyl acetate, the organosilicon content is 0.5-8 wt%, and the Zn-MOF-derived carbon content is 0.1-5 wt%.

[0017] The above describes a method for preparing a superhydrophobic microwave absorbing textile based on Zn-MOF-derived carbon, wherein the textile is made of polyester, nylon, cotton, Tencel, Modal, or acetate fiber.

[0018] The method for preparing a superhydrophobic microwave absorbing textile based on Zn-MOF-derived carbon as described above includes an impregnation time of 5–40 min, a liquid-holding rate of 100% during impregnation (liquid-holding rate = (mass of fabric after padding with the mixture – mass of fabric before padding with the mixture) / mass of fabric before padding with the mixture × 100%), a pre-drying temperature of 50–100 °C, a pre-drying time of 1–30 min, a baking temperature of 150–200 °C, and a baking time of 10–60 min.

[0019] The preparation method of superhydrophobic microwave absorbing textiles based on Zn-MOF-derived carbon, as described above, includes the following steps:

[0020] (1) Dissolve the zinc compound in a solvent to obtain a solution containing the zinc compound, and dissolve 2-methylimidazole in a solvent to obtain a solution containing 2-methylimidazole;

[0021] (2) Under stirring conditions, the solution containing 2-methylimidazole was added to the solution containing zinc compound. After the addition was completed, the mixture was stirred at a constant speed and allowed to stand. Then, it was washed repeatedly with anhydrous ethanol, and the white precipitate was collected by centrifugation. The precipitate was placed in a vacuum drying oven to dry, and Zn-MOF was obtained.

[0022] (3) In a tube furnace under a nitrogen atmosphere, the uniformly ground Zn-MOF is pyrolyzed and then naturally cooled to room temperature to obtain Zn-MOF-derived carbon.

[0023] The method for preparing a superhydrophobic microwave absorbing textile based on Zn-MOF-derived carbon as described above, wherein in step (1), the zinc compound is anhydrous zinc acetate, zinc nitrate hexahydrate, zinc chloride or zinc sulfate, and the solvent is ethanol, N,N-dimethylformamide (DMF), methanol or n-hexanol.

[0024] The method for preparing a superhydrophobic microwave absorbing textile based on Zn-MOF-derived carbon as described above, wherein the zinc compound content in the zinc compound solution is 0.5-5 wt%, and the 2-methylimidazole content in the 2-methylimidazole solution is 0.5-5 wt%.

[0025] In the preparation method of superhydrophobic microwave absorbing textile based on Zn-MOF-derived carbon as described above, the stirring temperature in step (2) is 15-40℃, and the stirring time after addition is 10-40 min.

[0026] In the preparation method of superhydrophobic microwave absorbing textile based on Zn-MOF-derived carbon as described above, the pyrolysis temperature in step (3) is 500-1000℃ and the time is 2h.

[0027] Invention Mechanism:

[0028] This invention utilizes a mixture of organosilicon and Zn-MOF-derived carbon to functionally finish textiles, resulting in superhydrophobic and microwave-absorbing textiles. On one hand, organosilicon possesses excellent low surface energy properties and high chemical stability, reducing the surface free energy of the finished fabric. Simultaneously, organosilicon forms an adhesive film on the fabric surface, effectively improving the durability and stability of the superhydrophobic and microwave-absorbing textile surface. On the other hand, Zn-MOF-derived carbon has an average particle size of 50–500 nm and a uniform particle size distribution. It not only possesses a regular polyhedral micro-rough structure but also exhibits excellent microwave absorption performance. Therefore, by using a mixture of organosilicon and Zn-MOF-derived carbon to functionally finish textiles, the synergistic effect of the low surface energy material organosilicon and Zn-MOF-derived carbon yields a multifunctional superhydrophobic and microwave-absorbing textile.

[0029] Two essential conditions for achieving superhydrophobic surfaces are low surface energy and a micro / nano rough structure. While organosilicon lowers the surface energy of textiles, it doesn't provide microwave absorption and offers only a limited improvement in hydrophobicity, failing to achieve true superhydrophobicity. Therefore, combining it with Zn-MOF-derived carbon finishing increases the surface roughness, further enhancing the hydrophobic effect. Zn-MOF-derived carbon not only constructs a micro / nano rough surface for textiles but also acts as a microwave absorber, endowing them with microwave absorption properties. Using Zn-MOF-derived carbon alone results in poor bonding strength with the fabric, hindering long-term microwave absorption. Combining it with organosilicon finishing not only effectively guarantees the microwave absorption performance of Zn-MOF-derived carbon but also further improves its durability. Finishing textiles with organosilicon and Zn-MOF-derived carbon imparts superhydrophobic properties, effectively preventing the adhesion or corrosion damage of large amounts of contaminants and extending the lifespan of microwave-absorbing textiles.

[0030] Beneficial effects:

[0031] (1) The method of the present invention is simple, the preparation conditions are mild, the raw materials are readily available, and it is easy to operate;

[0032] (2) The superhydrophobic absorbing textile fabric based on Zn-MOF-derived carbon prepared by the method of the present invention has excellent superhydrophobic absorbing properties, as well as self-cleaning and anti-fouling functions, effectively avoiding the adhesion or corrosion damage of a large number of pollutants, greatly extending the service life of the absorbing textile fabric, effectively solving the problems of electromagnetic pollution and electromagnetic interference, and at the same time having the characteristics of textile fabric flexibility, foldability, portability and cutability, with broad application prospects, meeting the needs of developing high value-added superhydrophobic absorbing textile fabrics. Attached Figure Description

[0033] Figure 1 Here is a scanning electron microscope image of the surface of Zn-MOF-derived carbon from Example 1;

[0034] Figure 2 This is a 3D reflection loss diagram of Zn-MOF-derived carbon absorbing material in Example 1;

[0035] Figure 3 Example 4 shows the water droplet contact angle on the surface of the textile.

[0036] Figure 4 This is a diagram illustrating the self-cleaning process of finishing textile surfaces in Example 4. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0038] The testing methods involved in the embodiments are as follows:

[0039] Water droplet contact angle: The contact angle was tested using a Kruss DSA30 video contact angle meter with a water volume of 5 μL. The water droplet was in contact with the fabric for 60 seconds before the reading was taken. Five measurements were taken at different locations on the same sample, and the average value was taken.

[0040] Wave absorption performance and effective absorption bandwidth of textiles: The finished textiles were cut into rectangular pieces with a length of 2.2 cm and a width of 1.5 cm. The rectangular pieces were clamped in a fixture, and waveguide tests were performed on the samples using an AV3672B vector network analyzer (VNA). The test band range was selected in the X-band (8.2~12.4GHz).

[0041] Microwave absorption performance and effective absorption bandwidth of Zn-MOF-derived carbon: Zn-MOF-derived carbon and paraffin were mixed at a mass ratio of 5:3. After the paraffin was melted in a 60℃ oven, the powder and liquid paraffin were mixed evenly and pressed into a mold. The sample model was a concentric ring with an outer diameter of 7 mm and an inner diameter of 3.04 mm. The electromagnetic parameters of the concentric ring were tested using an AV3672B vector network analyzer (VNA). The coaxial method was selected for the test mode, and the test band range was selected from 2 to 18 GHz.

[0042] Example 1

[0043] A method for preparing superhydrophobic microwave absorbing textiles based on Zn-MOF-derived carbon, the specific steps of which are as follows:

[0044] (1) Preparation of Zn-MOF-derived carbon;

[0045] (I) Dissolve anhydrous zinc acetate in ethanol to obtain a 3 wt% solution containing anhydrous zinc acetate; dissolve 2-methylimidazole in ethanol to obtain a 5 wt% solution containing 2-methylimidazole;

[0046] (II) Under stirring conditions, the solution containing 2-methylimidazole was added to the solution containing anhydrous zinc acetate. After the addition was completed, the mixture was stirred at a constant speed for 10 min and allowed to stand. Then, it was washed repeatedly with anhydrous ethanol, and the white precipitate was collected by centrifugation. The precipitate was placed in a vacuum drying oven to dry, and Zn-MOF was obtained. The stirring temperature was 40℃.

[0047] (III) In a tube furnace under a nitrogen atmosphere, the uniformly ground Zn-MOF was pyrolyzed at 1000℃ for 2 hours and then cooled to room temperature to obtain Zn-MOF-derived carbon.

[0048] like Figures 1-2 As shown, the prepared Zn-MOF-derived carbon has a regular polyhedral structure with an average diameter of 387.49 nm; the minimum reflection loss of Zn-MOF-derived carbon is -37.4 dB, and the effective absorption bandwidth is 3.7 GHz.

[0049] (2) Add hexadecyltrimethoxysilane and the Zn-MOF-derived carbon obtained in step (1) to n-hexane to obtain a mixed solution of hexadecyltrimethoxysilane and Zn-MOF-derived carbon; wherein, in the mixed solution, the content of hexadecyltrimethoxysilane is 2wt% and the content of Zn-MOF-derived carbon is 1wt%.

[0050] (3) The cotton fabric is immersed in a mixed solution of hexadecyltrimethoxysilane and Zn-MOF-derived carbon obtained in step (2), and is then subjected to padding, pre-drying and baking in sequence to obtain a superhydrophobic microwave absorbing textile based on Zn-MOF-derived carbon; wherein the immersion time is 10 min, the liquid retention rate during immersion is 100%, the pre-drying temperature is 80℃, the pre-drying time is 5 min, the baking temperature is 180℃, and the baking time is 30 min;

[0051] The superhydrophobic absorbing textile based on Zn-MOF-derived carbon has a water contact angle of 150.7°, a minimum reflection loss of -21.2dB, and an effective absorption bandwidth of 1.96GHz.

[0052] Comparative Example 1

[0053] A method for preparing a textile is basically the same as in Example 1, except that step (1) is omitted and Zn-MOF-derived carbon is not added in step (2), and a hexadecyltrimethoxysilane solution is prepared; the content of hexadecyltrimethoxysilane in Comparative Example 1 is the sum of the contents of hexadecyltrimethoxysilane and Zn-MOF-derived carbon in Example 1.

[0054] The resulting textile has a water contact angle of 132.5°, a minimum reflection loss of -12.4dB, and an effective absorption bandwidth of 0.11GHz.

[0055] Compared with Example 1, the water contact angle of Comparative Example 1 is much smaller than that of Example 1. This is because using PDMS alone can only reduce the surface energy of the textile surface and cannot construct a micro-nano-scale rough structure on the textile surface to create cavitation between the water droplet and the fabric surface.

[0056] Compared with Example 1, the minimum reflection loss of Comparative Example 1 is much greater than that of Example 1, and the effective absorption bandwidth is much smaller than that of Example 1. This is because PDMS cannot form a multi-layer or porous structure on the fabric surface to cause electromagnetic waves to be reflected multiple times inside, thus resulting in electromagnetic wave loss.

[0057] Comparative Example 2

[0058] A method for preparing a textile is basically the same as in Example 1, except that hexadecyltrimethoxysilane is not added in step (2), and a Zn-MOF-derived carbon solution is prepared; the content of Zn-MOF-derived carbon in Comparative Example 2 is the sum of the contents of hexadecyltrimethoxysilane and Zn-MOF-derived carbon in Example 1.

[0059] The fabricated wave textile has a water contact angle of 0°, a minimum reflection loss of -13.1dB, and an effective absorption bandwidth of 0.17GHz.

[0060] Compared with Example 1, the water contact angle of Comparative Example 2 is much smaller than that of Example 1. This is because the surface of cotton fabric is rich in hydroxyl groups and has high surface energy. Using Zn-MOF-derived carbon alone cannot improve the hydrophobic effect.

[0061] Compared with Example 1, the minimum reflection loss of Comparative Example 2 is much greater than that of Example 1, and the effective absorption bandwidth is much smaller than that of Example 1. This is because the bonding strength between the micro-nano structured Zn-MOF-derived carbon and the fabric is poor, and it is impossible to apply the Zn-MOF-derived carbon material to the fabric surface.

[0062] Example 2

[0063] A method for preparing superhydrophobic microwave absorbing textiles based on Zn-MOF-derived carbon, the specific steps of which are as follows:

[0064] (1) Preparation of Zn-MOF-derived carbon;

[0065] (I) Dissolve zinc nitrate hexahydrate in N,N-dimethylformamide to obtain a 1 wt% solution containing zinc nitrate hexahydrate; dissolve 2-methylimidazole in N,N-dimethylformamide to obtain a 3 wt% solution containing 2-methylimidazole;

[0066] (II) Under stirring conditions, a solution containing 2-methylimidazole was added to a solution containing zinc nitrate hexahydrate. After the addition was completed, the mixture was stirred at a constant speed for 20 min and allowed to stand. Then, it was washed repeatedly with anhydrous ethanol, and the white precipitate was collected by centrifugation. The precipitate was placed in a vacuum drying oven to dry, thus obtaining Zn-MOF. The stirring temperature was 40℃.

[0067] (III) In a tube furnace under a nitrogen atmosphere, the uniformly ground Zn-MOF was pyrolyzed at 1000℃ for 2 hours and then cooled to room temperature to obtain Zn-MOF-derived carbon.

[0068] The prepared Zn-MOF-derived carbon has a regular polyhedral structure with an average diameter of 256.44 nm; the minimum reflection loss of Zn-MOF-derived carbon is -38.8 dB, and the effective absorption bandwidth is 4.1 GHz.

[0069] (2) Add γ-methacryloxypropyltrimethoxysilane and the Zn-MOF-derived carbon obtained in step (1) to n-hexane to obtain a mixed solution of γ-methacryloxypropyltrimethoxysilane and Zn-MOF-derived carbon; wherein, in the mixed solution, the content of γ-methacryloxypropyltrimethoxysilane is 3wt% and the content of Zn-MOF-derived carbon is 3wt%;

[0070] (3) The polyester fabric is immersed in a mixed solution of γ-methacryloxypropyltrimethoxysilane and Zn-MOF-derived carbon obtained in step (2), and is then subjected to padding, pre-drying and baking in sequence to obtain a superhydrophobic microwave absorbing textile based on Zn-MOF-derived carbon; wherein the immersion time is 10 min, the liquid retention rate during immersion is 100%, the pre-drying temperature is 80℃, the pre-drying time is 5 min, the baking temperature is 180℃, and the baking time is 30 min;

[0071] The superhydrophobic absorbing textile based on Zn-MOF-derived carbon has a water contact angle of 151.3°, a minimum reflection loss of -26.4dB, and an effective absorption bandwidth of 2.32GHz.

[0072] Example 3

[0073] A method for preparing superhydrophobic microwave absorbing textiles based on Zn-MOF-derived carbon, the specific steps of which are as follows:

[0074] (1) Preparation of Zn-MOF-derived carbon;

[0075] (I) Dissolve zinc nitrate hexahydrate in methanol to obtain a 0.5 wt% solution containing zinc nitrate hexahydrate; dissolve 2-methylimidazole in methanol to obtain a 3 wt% solution containing 2-methylimidazole;

[0076] (II) Under stirring conditions, the solution containing 2-methylimidazole was added to the solution containing zinc nitrate hexahydrate. After the addition was completed, the mixture was stirred at a constant speed for 30 min and allowed to stand. Then, it was washed repeatedly with anhydrous ethanol, and the white precipitate was collected by centrifugation. The precipitate was placed in a vacuum drying oven to dry, thus obtaining Zn-MOF. The stirring temperature was 40℃.

[0077] (III) In a tube furnace under a nitrogen atmosphere, the uniformly ground Zn-MOF was pyrolyzed at 800°C for 2 hours and then cooled to room temperature to obtain Zn-MOF-derived carbon.

[0078] The prepared Zn-MOF-derived carbon has a regular polyhedral structure with an average diameter of 187.6 nm; the minimum reflection loss of Zn-MOF-derived carbon is -41.2 dB, and the effective absorption bandwidth is 4.4 GHz.

[0079] (2) Add polydimethylhydroxysiloxane (Aladdin, chemically pure reagent) and Zn-MOF-derived carbon obtained in step (1) to benzyl alcohol to prepare a mixed solution of polydimethylhydroxysiloxane and Zn-MOF-derived carbon; wherein, in the mixed solution, the content of polydimethylhydroxysiloxane is 4wt% and the content of Zn-MOF-derived carbon is 5wt%.

[0080] (3) The polyester fabric is immersed in a mixed solution of polydimethylhydroxysiloxane and Zn-MOF-derived carbon obtained in step (2), and then subjected to padding, pre-drying and baking in sequence to obtain a superhydrophobic and microwave absorbing textile based on Zn-MOF-derived carbon; wherein the immersion time is 10 min, the liquid retention rate during immersion is 100%, the pre-drying temperature is 80℃, the pre-drying time is 5 min, the baking temperature is 180℃, and the baking time is 30 min;

[0081] The superhydrophobic absorbing textile based on Zn-MOF-derived carbon has a water contact angle of 154.7°, a minimum reflection loss of -33.4dB, and an effective absorption bandwidth of 2.81GHz.

[0082] Example 4

[0083] A method for preparing superhydrophobic microwave absorbing textiles based on Zn-MOF-derived carbon, the specific steps of which are as follows:

[0084] (1) Preparation of Zn-MOF-derived carbon;

[0085] (I) Dissolve zinc nitrate hexahydrate in methanol to obtain a solution containing zinc nitrate hexahydrate with a concentration of 0.5 wt%; dissolve 2-methylimidazole in methanol to obtain a solution containing 2-methylimidazole with a concentration of 1 wt%;

[0086] (II) Under stirring conditions, the solution containing 2-methylimidazole was added to the solution containing zinc nitrate hexahydrate. After the addition was completed, the mixture was stirred at a constant speed for 30 min and allowed to stand. Then, it was washed repeatedly with anhydrous ethanol, and the white precipitate was collected by centrifugation. The precipitate was placed in a vacuum drying oven to dry, thus obtaining Zn-MOF. The stirring temperature was 25℃.

[0087] (III) In a tube furnace under a nitrogen atmosphere, the uniformly ground Zn-MOF was pyrolyzed at 800°C for 2 hours and then cooled to room temperature to obtain Zn-MOF-derived carbon.

[0088] The prepared Zn-MOF-derived carbon has a regular polyhedral structure with an average diameter of 73.82 nm; the minimum reflection loss of Zn-MOF-derived carbon is -43.7 dB, and the effective absorption bandwidth is 4.9 GHz.

[0089] (2) Polydimethylsiloxane (Dow Corning, Inc., chemically pure reagent) and Zn-MOF-derived carbon obtained in step (1) are added to isopropanol to prepare a mixed solution of polydimethylsiloxane and Zn-MOF-derived carbon; wherein, in the mixed solution, the content of polydimethylsiloxane is 4 wt% and the content of Zn-MOF-derived carbon is 5 wt%.

[0090] (3) The cotton fabric is immersed in the mixed solution of polydimethylsiloxane and Zn-MOF-derived carbon obtained in step (2), and is then subjected to padding, pre-drying and baking in sequence to obtain a superhydrophobic microwave absorbing textile based on Zn-MOF-derived carbon; wherein the immersion time is 30 min, the liquid retention rate during immersion is 100%, the pre-drying temperature is 80℃, the pre-drying time is 5 min, the baking temperature is 180℃, and the baking time is 30 min;

[0091] The water contact angle of the superhydrophobic microwave absorbing textile based on Zn-MOF-derived carbon was 156.8° (e.g., Figure 3 As shown in the figure, the minimum reflection loss is -35.8dB and the effective absorption bandwidth is 3.21GHz.

[0092] like Figure 4 As shown, a superhydrophobic microwave absorbing textile based on Zn-MOF-derived carbon was adhered to a glass surface and placed at an angle. Purple chalk dust, simulating dust, was evenly sprinkled on the surface. The surface condition of the textile was observed by watching water droplets roll off, thus investigating its self-cleaning properties. The water droplets rolled rapidly on the surface of the textile, carrying away a certain amount of purple chalk dust, which then detached from the surface, achieving the purpose of cleaning the surface without leaving any stains, demonstrating the excellent self-cleaning properties of the textile.

[0093] Example 5

[0094] A method for preparing superhydrophobic microwave absorbing textiles based on Zn-MOF-derived carbon, the specific steps of which are as follows:

[0095] (1) Preparation of Zn-MOF-derived carbon;

[0096] (I) Dissolve anhydrous zinc acetate in ethanol to obtain a 3 wt% solution containing anhydrous zinc acetate; dissolve 2-methylimidazole in ethanol to obtain a 1 wt% solution containing 2-methylimidazole;

[0097] (II) Under stirring conditions, the solution containing 2-methylimidazole was added to the solution containing anhydrous zinc acetate. After the addition was completed, the mixture was stirred at a constant speed for 30 min and allowed to stand. Then, it was washed repeatedly with anhydrous ethanol, and the white precipitate was collected by centrifugation. The precipitate was placed in a vacuum drying oven to dry, thus obtaining Zn-MOF. The stirring temperature was 25℃.

[0098] (III) In a tube furnace under a nitrogen atmosphere, the uniformly ground Zn-MOF was pyrolyzed at 500°C for 2 hours and then cooled to room temperature to obtain Zn-MOF-derived carbon.

[0099] The prepared Zn-MOF-derived carbon has a regular polyhedral structure with an average diameter of 296.36 nm; the minimum reflection loss of Zn-MOF-derived carbon is -39.4 dB, and the effective absorption bandwidth is 4 GHz.

[0100] (2) Add polydimethylhydroxysiloxane (Aladdin, chemically pure reagent) and Zn-MOF-derived carbon obtained in step (1) to isopropanol to prepare a mixed solution of polydimethylhydroxysiloxane and Zn-MOF-derived carbon; wherein, in the mixed solution, the content of polydimethylhydroxysiloxane is 3wt% and the content of Zn-MOF-derived carbon is 3wt%.

[0101] (3) The polyester fabric is immersed in a mixed solution of polydimethylhydroxysiloxane and Zn-MOF-derived carbon obtained in step (2), and then subjected to padding, pre-drying and baking in sequence to obtain a superhydrophobic and microwave absorbing textile based on Zn-MOF-derived carbon; wherein the immersion time is 20 min, the liquid retention rate during immersion is 100%, the pre-drying temperature is 80℃, the pre-drying time is 5 min, the baking temperature is 150℃, and the baking time is 30 min;

[0102] The superhydrophobic absorbing textile based on Zn-MOF-derived carbon has a water contact angle of 153.3°, a minimum reflection loss of -29.6dB, and an effective absorption bandwidth of 2.87GHz.

[0103] Example 6

[0104] A method for preparing superhydrophobic microwave absorbing textiles based on Zn-MOF-derived carbon, the specific steps of which are as follows:

[0105] (1) Preparation of Zn-MOF-derived carbon;

[0106] (I) Dissolve zinc chloride in n-hexanol to obtain a zinc chloride-containing solution with a concentration of 0.5 wt%; dissolve 2-methylimidazole in n-hexanol to obtain a 2-methylimidazole-containing solution with a concentration of 0.5 wt%;

[0107] (II) Under stirring conditions, the solution containing 2-methylimidazole was added to the solution containing zinc chloride. After the addition was completed, the mixture was stirred at a constant speed for 10 min and allowed to stand. Then, it was washed repeatedly with anhydrous ethanol, and the white precipitate was collected by centrifugation. The precipitate was placed in a vacuum drying oven to dry, thus obtaining Zn-MOF. The stirring temperature was 35℃.

[0108] (III) In a tube furnace under a nitrogen atmosphere, the uniformly ground Zn-MOF was pyrolyzed at 500°C for 2 hours and then cooled to room temperature to obtain Zn-MOF-derived carbon.

[0109] The prepared Zn-MOF-derived carbon has a regular polyhedral structure with an average diameter of 82.31 nm; the minimum reflection loss of Zn-MOF-derived carbon is -42.3 dB, and the effective absorption bandwidth is 4.9 GHz.

[0110] (2) Add hexadecyltrimethoxysilane and the Zn-MOF-derived carbon obtained in step (1) to N,N-dimethylformamide to obtain a mixed solution of hexadecyltrimethoxysilane and Zn-MOF-derived carbon; wherein, in the mixed solution, the content of hexadecyltrimethoxysilane is 0.5wt% and the content of Zn-MOF-derived carbon is 0.1wt%.

[0111] (3) The Tencel fabric is immersed in a mixed solution of hexadecyltrimethoxysilane and Zn-MOF-derived carbon obtained in step (2), and then subjected to padding, pre-drying and baking in sequence to obtain a superhydrophobic microwave absorbing textile based on Zn-MOF-derived carbon; wherein the immersion time is 5 min, the liquid retention rate during immersion is 100%, the pre-drying temperature is 50℃, the pre-drying time is 30 min, the baking temperature is 150℃, and the baking time is 60 min;

[0112] The superhydrophobic absorbing textile based on Zn-MOF-derived carbon has a water contact angle of 151.7°, a minimum reflection loss of -23.7dB, and an effective absorption bandwidth of 2.16GHz.

[0113] Example 7

[0114] A method for preparing superhydrophobic microwave absorbing textiles based on Zn-MOF-derived carbon, the specific steps of which are as follows:

[0115] (1) Preparation of Zn-MOF-derived carbon;

[0116] (I) Dissolve zinc sulfate in n-hexanol to obtain a zinc sulfate solution with a concentration of 5 wt%; dissolve 2-methylimidazole in n-hexanol to obtain a 2-methylimidazole solution with a concentration of 5 wt%;

[0117] (II) Under stirring conditions, the solution containing 2-methylimidazole was added to the solution containing zinc sulfate. After the addition was completed, the mixture was stirred at a constant speed for 40 min and allowed to stand. Then, it was washed repeatedly with anhydrous ethanol, and the white precipitate was collected by centrifugation. The precipitate was placed in a vacuum drying oven to dry, thus obtaining Zn-MOF. The stirring temperature was 15℃.

[0118] (III) In a tube furnace under a nitrogen atmosphere, the uniformly ground Zn-MOF was pyrolyzed at 1000℃ for 2 hours and then cooled to room temperature to obtain Zn-MOF-derived carbon.

[0119] The prepared Zn-MOF-derived carbon has a regular polyhedral structure with an average diameter of 467.29 nm; the minimum reflection loss of Zn-MOF-derived carbon is -32.7 dB, and the effective absorption bandwidth is 3.6 GHz.

[0120] (2) Add hexadecyltrimethoxysilane and the Zn-MOF-derived carbon obtained in step (1) to ethyl acetate to prepare a mixed solution of hexadecyltrimethoxysilane and Zn-MOF-derived carbon; wherein, in the mixed solution, the content of hexadecyltrimethoxysilane is 8wt% and the content of Zn-MOF-derived carbon is 5wt%.

[0121] (3) The cellulose acetate fabric is immersed in a mixed solution of hexadecyltrimethoxysilane and Zn-MOF-derived carbon obtained in step (2), and then subjected to padding, pre-drying and baking in sequence to obtain a superhydrophobic microwave absorbing textile based on Zn-MOF-derived carbon; wherein the immersion time is 40 min, the liquid retention rate during immersion is 100%, the pre-drying temperature is 100℃, the pre-drying time is 1 min, the baking temperature is 200℃, and the baking time is 10 min;

[0122] The superhydrophobic absorbing textile based on Zn-MOF-derived carbon has a water contact angle of 155.1°, a minimum reflection loss of -32.5dB, and an effective absorption bandwidth of 3.08GHz.

Claims

1. A method for the preparation of a Zn-MOF derived carbon based superhydrophobic wave-absorbing textile, characterized in that: The textile is immersed in a mixed solution of silicone and Zn-MOF derived carbon, and then is subjected to padding, pre-drying and baking in sequence to obtain the super-hydrophobic wave-absorbing textile based on Zn-MOF derived carbon. The silicone is hexadecyl trimethoxysilane, gamma-methacryloxypropyl trimethoxysilane, polydimethylsiloxane or polydimethylhydroxysiloxane. The Zn-MOF derived carbon has a regular polyhedral structure with a diameter of 50-500 nm, and the minimum reflection loss of the Zn-MOF derived carbon is -20 to -50 dB. The preparation steps of the Zn-MOF derived carbon are as follows: (1) Dissolving a zinc compound in a solvent to obtain a solution containing the zinc compound, and dissolving 2-methylimidazole in a solvent to obtain a solution containing 2-methylimidazole; (2) Under stirring, the solution containing 2-methylimidazole is added to the solution containing the zinc compound, after the addition is completed, uniform stirring is carried out and then the mixture is left to stand, and then the mixture is repeatedly washed with anhydrous ethanol, the precipitate is collected by centrifugation, and the precipitate is dried in a vacuum drying oven to obtain the Zn-MOF; (3) In a tube furnace, the uniformly ground Zn-MOF is pyrolyzed under a nitrogen atmosphere and then cooled to room temperature to obtain the Zn-MOF derived carbon; In step (3), the pyrolysis temperature is 500-1000℃, and the time is 2h. The water contact angle of the super-hydrophobic wave-absorbing textile based on Zn-MOF derived carbon is not less than 150.7°, and the minimum reflection loss is not higher than -21.2 dB.

2. A method of preparing a Zn-MOF derived carbon based superhydrophobic wave- absorbing textile according to claim 1, characterized in that, In the mixed solution of silicone and Zn-MOF derived carbon, the solvent is isopropyl alcohol, n-hexane, benzyl alcohol, acetone, N,N-dimethylformamide or ethyl acetate, the content of silicone is 0.5-8wt%, and the content of Zn-MOF derived carbon is 0.1-5wt%.

3. A method of preparing a Zn-MOF derived carbon based superhydrophobic wave- absorbing textile according to claim 1, characterized in that, The textile is polyester, nylon, cotton, Tencel, modal or acetate fiber.

4. A method of preparing a Zn-MOF derived carbon based superhydrophobic wave- absorbing textile according to claim 1, characterized in that, The immersion time is 5-40min, the belt liquid rate during padding is 100%, the pre-drying temperature is 50-100℃, the pre-drying time is 1-30min, the baking temperature is 150-200℃, and the baking time is 10-60min.

5. A method of preparing a Zn-MOF derived carbon based superhydrophobic wave- absorbing textile according to claim 1, characterized in that, In step (1), the zinc compound is anhydrous zinc acetate, zinc nitrate hexahydrate, zinc chloride or zinc sulfate, and the solvent is ethanol, N,N-dimethylformamide, methanol or n-hexanol.

6. A method of preparing a Zn-MOF derived carbon based superhydrophobic wave- absorbing textile according to claim 5, characterized in that, In the solution containing the zinc compound, the content of the zinc compound is 0.5-5wt%, and in the solution containing 2-methylimidazole, the content of 2-methylimidazole is 0.5-5wt%.

7. A method of preparing a Zn-MOF derived carbon based superhydrophobic wave- absorbing textile according to claim 1, characterized in that, In step (2), the stirring temperature is 15-40℃, and the stirring time after the addition is completed is 10-40min.

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