Cotton fabric with radiation heating and flame-retardant composite functions and preparation method thereof

Abstract

The invention provides a cotton fabric with a radiation heating and flame-retardant composite function and a preparation method thereof, and belongs to the technical field of composite functional materials.The cotton fabric with the radiation heating and flame-retardant composite function comprises a substrate and at least two composite layer units coated on the substrate in a stacked mode, and each composite layer unit comprises a PDA (Personal Digital Assistant) layer and an MXene layer coated on the PDA layer. Aiming at the problems of high toxicity, single function, complex process and the like in the aspect of flame-retardant and heating functional fabrics in the prior art, the invention provides the multifunctional cotton fabric prepared by a layer-by-layer self-assembly technology of MXene and PDA, and the fabric has the composite functions of efficient flame retardance and radiation heating, and also has environmental protection property and comfort, and can be used for preparing the flame-retardant and heating functional fabrics. The fabric is suitable for the fields of intelligent clothes, safety protection and warm-keeping equipment.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite functional materials, and particularly relates to a cotton fabric with radiation heating and flame retardant composite functions and a preparation method thereof. Background Art

[0002] In recent years, the demand for functional textiles in the fields of smart clothing, household items and safety protection has increased rapidly. In particular, the application of fabrics with both heating and flame retardant functions in cold protection and safety protection has received extensive attention. However, the current technical solutions still have obvious limitations in realizing these functions, and the specific analysis is as follows:

[0003] The current technical methods for flame retardant fabrics mainly include: 1. Traditional chemical flame retardants: Halogen flame retardants (such as bromides) or phosphorus-based flame retardants are used to introduce functional additives into fabrics. However, the problems of the above methods are as follows: a. Environmental pollution: Halogen flame retardants will release toxic gases during combustion, posing a threat to the environment and human health; b. Single performance: Most of them focus on single-sided flame retardancy in the gas phase or condensed phase, and it is difficult to provide comprehensive protection; c. Poor durability: Flame retardants are easy to gradually lose during washing or use, resulting in a significant decline in the flame retardant performance of fabrics. 2. High-temperature coating materials: Inorganic materials (such as ceramic coatings or silicon-based materials) are used to form a flame retardant protective layer on the fabric surface. The problems of the above methods are as follows: a. Affecting softness and comfort: Inorganic coatings are usually thick, increasing the rigidity and weight of the fabric; b. Complex process and high cost: High-temperature sintering or special treatment is required, and it is difficult to adapt to large-scale production.

[0004] The current heating function fabrics are mainly realized in the following ways: 1. Metal wire embedding method: Metal wires (such as copper wires or nickel-chromium wires) are embedded in the fabric, and the heating function is realized by passing an electric current. However, the problems of the above methods are as follows: a. The softness of the fabric decreases: Metal wires increase the rigidity of the fabric and affect comfort; b. Poor uniformity: The heat conduction and temperature rise are uneven, and hot spots or local overheating are likely to occur; c. Safety hazards: The breakage of metal wires may cause circuit short circuits or fire risks. 2. Conductive coating method: Conductive coating materials (such as graphene or carbon nanotubes) are sprayed on the fabric surface, and the heating function is realized by using their conductivity. The problems of the above methods are as follows: a. Insufficient coating adhesion: The coating is easy to fall off due to washing or friction, resulting in the attenuation of the heating function; b. Poor ultraviolet stability: Some coatings are easy to age under ultraviolet irradiation, affecting the service life.

[0005] Therefore, the existing multifunctional textile technology faces the following challenges in integrating flame retardant and heating functions: 1. Function conflict: Flame retardant and heating functions often require different materials to achieve, and these materials may be contradictory in terms of process or performance, resulting in poor effectiveness of the composite function; 2. Complex composite process: The process of combining flame retardants with thermal conductive materials on fabrics usually requires multiple steps, resulting in high production costs and low efficiency. 3. Lack of comfort: The materials or processes of existing technical solutions may have an adverse impact on the softness and breathability of fabrics, restricting their application scenarios.

[0006] Analysis of the root causes of the above problems yields the following results: 1. Limitations in material selection: Most existing flame retardants have toxicity or environmental pollution problems and are difficult to meet the requirements of green environmental protection; there is still much room for improvement in the adhesion, uniformity, and stability of heat-generating materials.

[0007] 2. Complexity of process design: The preparation of multifunctional coatings often requires high-temperature treatment or complex multi-step processes, increasing the production difficulty and cost.

[0008] 3. Lack of comprehensive performance: When realizing multifunctional textiles, the combination efficiency of flame retardant and heat generation functions is not high, and the use comfort such as the softness and breathability of fabrics is affected.

[0009] In summary, the existing technologies have problems such as unenvironmental friendly materials, single performance, poor durability, and complex processes in the research and development of flame retardant and heat generation functional textiles. Summary of the Invention

[0010] To address these problems, the present invention proposes a solution based on the layer-by-layer self-assembly technology of MXene and PDA to achieve the efficient combination of flame retardant and radiative heat generation functions, while ensuring the softness, durability, and environmental friendliness of the fabric, fundamentally overcoming the deficiencies of the existing technologies.

[0011] The first aspect of the present invention provides a cotton fabric with radiative heat generation and flame retardant composite functions, comprising a substrate and at least two composite layer units laminated and coated on the substrate, and each composite layer unit includes a PDA layer and an MXene layer coated on the PDA layer.

[0012] In view of the problems of high toxicity, single function, complex process, etc. existing in the prior art in the aspect of flame retardant and heat generation functional fabrics, the present invention proposes a multifunctional cotton fabric prepared by the layer-by-layer self-assembly technology of MXene and PDA. This fabric simultaneously has the composite functions of high-efficiency flame retardancy and radiative heat generation, and also has environmental friendliness and comfort, and is applicable to the fields of smart clothing, safety protection, and thermal insulation equipment; among them, MXene is a material with low infrared emissivity, endowing the fabric with efficient radiative heat generation function, and at the same time achieving flame retardant performance through the condensed phase effect, while PDA (dopamine) has excellent ultraviolet shielding function and realizes the synergistic flame retardant effect by capturing free radicals in the gas phase to prevent the combustion chain reaction.

[0013] In some embodiments, a top PDA layer is also coated on the composite layer unit.

[0014] The second object of the present invention is to provide a preparation method of a cotton fabric, and the preparation method specifically includes the following steps: S1. Prepare a dopamine solution with a concentration of 1 - 2 mg / mL; S2. Prepare an MXene dispersion with a concentration of 1 - 2 mg / ml; S3. Adopt the dopamine self - polymerization method, immerse the substrate into the dopamine solution prepared in step S1, and then adopt the hydrogen - bond and electrostatic - force adsorption method to immerse it into the MXene dispersion prepared in step S2 to complete the deposition of a composite layer unit. S4. According to the number of pre - designed composite layer units, repeat step S3 to finally obtain a flame - retardant cotton fabric.

[0015] Compared with the prior art, the present invention uses the Layer - by - Layer Self - Assembly (LbL) technology to achieve uniform deposition of MXene and PDA on the fabric surface through electrostatic adsorption.

[0016] In some embodiments, the specific operation of step S1 is as follows: Dissolve dopamine in a Tris - base buffer solution, and the concentration of the Tris - base buffer solution is 10 mM and the pH is 8.5.

[0017] In some embodiments, the specific operation of step S2 is as follows: Add Ti3AlC2 powder to a hydrofluoric acid solution with a concentration of 10 - 30%, stir at room temperature for 24 hours to remove Al atoms to obtain Ti3C2Tx, ultrasonicate for 1 hour, and then centrifuge and wash the product with deionized water multiple times until the pH value of the solution is close to neutral.

[0018] In some embodiments, the substrate in step S3 is a cotton fabric substrate, and the cotton fabric substrate is pretreated. The pretreatment steps are as follows: Wash the cotton fabric substrate with deionized water and ethanol, remove surface impurities and grease, and then place it in an oven at 55 - 65°C for drying for 2 - 3 h.

[0019] In some embodiments, in step S3, the specific steps of adopting the dopamine self - polymerization method and the hydrogen - bond and electrostatic - force adsorption method are as follows: Immerse the pretreated cotton fabric substrate into the dopamine solution prepared in step S1, keep it for 5 - 10 min, take it out and press out most of the liquid, and then dry it at 55 - 65°C for 10 - 15 min; Then immerse it in the MXene dispersion prepared in step S2 for 5 - 10 min. After taking it out, press to dry most of the liquid, and dry it at 55 - 65 °C for 10 - 15 min.

[0020] Compared with the prior art, in the preparation process of the present invention, each layer of the coating is dried to improve the adhesion and stability, and finally a stable MXene-PDA composite coating is formed.

[0021] In some embodiments, step S5 is further included. By using the electrostatic adsorption method, the obtained cotton fabric is immersed in the dopamine solution prepared in step S1 to obtain a cotton fabric with a top PDA layer.

[0022] Compared with the prior art, the present invention has the following advantages: 1. High-efficiency flame retardancy: The synergistic effect of the gas-phase and condensed-phase flame retardancy mechanisms enables the fabric to meet the high-level flame retardancy standard.

[0023] 2. Excellent heating function: MXene provides a low infrared emissivity, enabling rapid heating and uniform heat distribution; PDA shields ultraviolet rays, protects the coating material from aging, and extends the functional life.

[0024] 3. Environmental protection and safety: Both MXene and PDA are non-toxic materials, avoiding environmental pollution and health hazards caused by harmful components in traditional flame retardants; The green preparation process is suitable for the application of functional fabrics for close-to-skin wearing. Specific embodiments

[0025] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following detailed description of the specific embodiments of the present invention is provided. It should be noted that the following embodiments are only used to illustrate the implementation methods and typical parameters of the present invention, and are not used to limit the parameter range described in the present invention. Reasonable changes derived therefrom are still within the protection scope of the claims of the present invention.

[0026] It should be noted that the endpoints and any values in the ranges disclosed herein are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0027] Unless otherwise defined, all terms, symbols, and other scientific terms used herein are intended to have the same meaning as commonly understood by those skilled in the art to which this invention pertains. In some cases, terms with commonly understood meanings are defined herein for purposes of clarification or ease of reference, and such definitions should not be construed as indicating a significant difference from the conventional understanding in the art. The technical methods described or referenced herein are generally well understood by those skilled in the art and are employed by conventional methods. Unless otherwise stated, the use of commercially available kits, reagents, and instruments is carried out in accordance with the protocols and parameters provided by the manufacturers.

[0028] Based on the content of the invention, the technical problems analyzed and solved by the present invention using the above technical means are as follows: I. Layer-by-layer self-assembly technology based on MXene and PDA 1. Technical means: A. MXene and PDA are used as functional materials, and a multifunctional coating is constructed on the surface of cotton fabric through the layer-by-layer self-assembly method of electrostatic adsorption; B. A uniform and stable composite coating is achieved by alternately depositing MXene and PDA.

[0029] 2. Technical problems solved: A. Solved the problems of uneven distribution of functional materials and poor adhesion in traditional coating methods; B. Improved the controllability and repeatability of the coating preparation process, making it suitable for large-scale industrial production.

[0030] II. Flame retardant effect of MXene in the condensed phase 1. Technical means: A. MXene forms a char layer at high temperature to block heat and oxygen; B. The arrangement of MXene in the coating is optimized to improve the heat insulation and antioxidant properties.

[0031] 2. Technical problems solved: A. Solved the problem of insufficient heat insulation performance of traditional flame retardant materials in the condensed phase; B. Improved the flame retardant efficiency and durability of the fabric.

[0032] III. Flame retardant effect of PDA in the gas phase 1. Technical means: A. PDA captures combustion free radicals at high temperature to block the chain combustion reaction; B. PDA also plays a role in enhancing the interlayer bonding force in the coating, improving the coating stability.

[0033] 2. Technical problems solved: A. It solves the problem that the traditional gas-phase flame retardant has poor effect due to insufficient heat resistance. B. It realizes the synergistic effect of the gas phase and the condensed phase in the flame retardant effect, and improves the overall flame retardant performance.

[0034] IV. Heating characteristics of MXene with low infrared emissivity 1. Technical means: A. As the core material of the functional coating, MXene can quickly radiate heat after absorbing external heat due to its low infrared emissivity characteristics. B. By optimizing the dispersion and arrangement of MXene, the thermal radiation performance of the fabric surface is made uniform.

[0035] 2. Technical problems solved: A. It solves the problems of low thermal management efficiency and uneven heat distribution of traditional thermal radiation materials. B. It realizes the efficient thermal management ability of cotton fabrics in low-temperature environments.

[0036] V. UV shielding and photo-stabilization functions of PDA 1. Technical means: A. PDA can absorb ultraviolet rays and prevent the coating from undergoing photo-aging under sunlight. B. By introducing PDA, the stability and durability of the MXene coating during long-term use are enhanced.

[0037] 2. Technical problems solved: A. It solves the aging problem of traditional fabric functional coatings caused by ultraviolet rays. B. It extends the service life of the coating and reduces the maintenance and replacement costs.

[0038] VI. Selection of environmentally friendly and safe multifunctional coating materials 1. Technical means: A. Using two green and environmentally friendly materials, MXene and PDA, avoids the use of toxic and harmful substances in traditional flame retardant coatings. B. The coating material does not release harmful gases and meets the needs of human body close-fitting use.

[0039] 2. Technical problems solved: A. It solves the problem of the adverse effects of traditional flame retardants on the environment and human health. B. It provides a functional textile solution with higher safety.

[0040] VII. Achievement of multifunctional composite effects 1. Technical means: A. The MXene and PDA coatings act synergistically through the flame retardant mechanisms of the gas phase and the condensed phase, significantly improving the flame retardant performance of the fabric. B. It simultaneously has an efficient radiant heating function and an ultraviolet shielding function, forming a multifunctional integrated composite coating.

[0041] 2. Technical problems to be solved: A. It solves the problem of the single function of traditional coatings; B. Integrating multiple functions in one coating expands the application scenarios and market value of the product.

[0042] The technical effects of the present invention are described below in conjunction with specific embodiments.

[0043] Example 1 This example provides a cotton fabric with a combined function of radiant heating and flame retardancy, which is prepared by the following method: S1. Prepare a 2 mg / mL dopamine solution: Dissolve dopamine in a Tris-base buffer solution with a concentration of 10 mM and a pH of 8.5. S2. Prepare an MXene dispersion with a concentration of 1 - 2 mg / ml: Add Ti3AlC2 powder to a concentrated hydrofluoric acid solution (with a concentration of about 10% - 30%), stir at room temperature for 24 hours to remove Al atoms to obtain Ti3C2Tx, wash the product by centrifugation with deionized water multiple times until the pH value of the solution is close to neutral, and prepare an MXene dispersion with a concentration of 1 - 2 mg / mL by ultrasonic dispersion. S3. Wash the cotton fabric substrate with deionized water and ethanol, remove surface impurities and grease, and then place it in an oven at 55 - 65 °C for drying for 2 - 3 hours. Immerse the pretreated cotton fabric substrate in the dopamine solution for 5 minutes, take it out, gently shake off the liquid, and dry it at 60 °C for 10 minutes; then immerse the fabric in the MXene dispersion for 5 minutes, take it out, shake off the liquid, and dry it at 60 °C for 10 minutes. S4. According to the preset composite layer unit being 2, repeat step S3 once, and finally obtain the cotton fabric. S5. Immerse the cotton fabric in the dopamine solution for 5 minutes, take it out, gently shake off the liquid, and dry it at 60 °C for 10 minutes to obtain a cotton fabric with a top layer of PDA layer.

[0044] Example 2 This example provides a cotton fabric with a combined function of radiant heating and flame retardancy. The difference from Example 1 is only that in step S4 of this example, step S3 is repeated twice, and the others are the same as in Example 1, so they will not be elaborated here.

[0045] Example 3 This embodiment provides a cotton fabric with the combined functions of radiant heating and flame retardancy. The difference from Embodiment 1 is only that in step S4 of this embodiment, step S3 is repeated three times, and the rest is the same as in Embodiment 1, which will not be elaborated here.

[0046] Embodiment 4 This embodiment provides a cotton fabric with the combined functions of radiant heating and flame retardancy. The difference from Embodiment 1 is only that this embodiment does not include step S5, and the rest is the same as in Embodiment 1, which will not be elaborated here.

[0047] Comparative Example 1 This comparative example provides a cotton fabric that has not been subjected to any treatment.

[0048] The cotton fabric prepared in Embodiment 1 and the cotton fabric of Comparative Example 1 were subjected to performance tests. The specific items, processes, and results of the tests are as follows: I. Flame Retardancy Test The test method is as follows: 1. The vertical burning test method (in accordance with the GB / T 5455 standard) was adopted.

[0049] 2. A comparative test was conducted using the cotton fabric prepared in Embodiment 1 of the present invention and the untreated cotton fabric of Comparative Example 1.

[0050] 3. The burning time, char residue rate, and flame spread length were recorded.

[0051] The test results are shown in Table 1: Table 1: Test Results of Flame Retardancy of Cotton Fabrics Prepared in Embodiment 1 and Comparative Example 1 A B C D 1 Sample Combustion time (s) Residual carbon rate (%) Flame spread length (cm) 2 Comparative example 1 10 2.5 15 3 Example 1 Non-combustible 55 0 Conclusion: 1. The MXene-PDA coating of the present invention significantly improves the flame retardancy of the cotton fabric, and the fabric achieves a non-combustible state; 2. The formation of the condensed-phase carbonized layer of MXene and the free radical capture effect of PDA ensure the synergistic flame retardancy of the gas phase and the condensed phase.

[0052] II. Radiant Heating Performance Test The test method is as follows: 1. An infrared thermal imager was used to monitor the temperature change of the fabric under illumination or heating conditions; 2. The heating rate and temperature distribution uniformity of the cotton fabric prepared in Embodiment 1 of the present invention were compared with those of the untreated cotton fabric of Comparative Example 1.

[0053] Test Results: 1. Under the same illumination conditions, the surface temperature of the cotton fabric prepared in Embodiment 1 of the present invention is more than 10 °C higher than that of the untreated fabric prepared in Comparative Example 1; 2. Within 30 seconds, the cotton fabric prepared in Example 1 of the present invention reaches a stable temperature of 50 °C, while the untreated fabric prepared in Comparative Example 1 is only 35 °C.

[0054] 3. The surface temperature distribution of the cotton fabric prepared in Example 1 of the present invention is uniform, without obvious hot spots.

[0055] Conclusion: 1. The low infrared emissivity characteristic of MXene enables the fabric to have fast and efficient thermal radiation performance; 2. The uniform coating structure of the present invention ensures the uniformity of heat distribution and improves the use comfort.

[0056] III. Ultraviolet shielding ability test The test method is as follows: 1. According to the AATCC TM183 standard, measure the ultraviolet transmittance (UPF value) of the fabric.

[0057] 2. Compare the ultraviolet protection ability of the cotton fabric prepared in Example 1 of the present invention with that of the untreated cotton fabric in Comparative Example 1.

[0058] The test results are shown in Table 2: Table 2: Test results of ultraviolet shielding performance of cotton fabrics prepared in Example 1 and Comparative Example 1 A B C 1 Sample Ultraviolet transmittance (%) UPF value 2 Comparative example 1 65 15 3 Example 1 5 50+ Conclusion: 1. The PDA coating of the present invention significantly enhances the ultraviolet shielding ability, enabling the cotton fabric prepared in the present invention to reach an excellent ultraviolet protection level; 2. The stability of the coating of the present invention ensures the light protection effect during long-term use.

[0059] In summary, the following conclusions can be obtained from the above test results: I. The flame retardancy of the present invention is significantly improved, meeting the high safety requirements 1. Synergistic flame retardancy mechanism: Condensed-phase flame retardancy: MXene forms a dense charred heat-insulating layer at high temperature, blocking the conduction of heat and oxygen; Gas-phase flame retardancy: PDA captures free radicals during combustion, blocking the combustion chain reaction.

[0060] 2. Advantages and effects: The flame retardancy is greatly improved, and the char residue rate of the fabric in the vertical burning test can be increased to 40%-60%; 3. Principle analysis: Through the synergistic effect of the gas phase and the condensed phase, the flame retardancy efficiency is fundamentally improved, overcoming the disadvantages of traditional flame retardants such as high toxicity and single performance.

[0061] II. Excellent Radiant Heating Performance and Enhanced Thermal Management Capability 1. Efficient Thermal Radiation: MXene has a low infrared emissivity and can quickly absorb and radiate heat; The coating design ensures uniform heat distribution without local overheating.

[0062] 2. Ultraviolet Shielding Effect: PDA protects the fabric coating from photoaging by absorbing ultraviolet light, extending its service life.

[0063] 3. Advantages and Effects: The fabric coated with the coating has a fast heating rate and uniform temperature distribution; Even in a low-temperature environment, the fabric can still effectively improve thermal management performance.

[0064] 4. Principle Analysis: Through the efficient infrared radiation characteristics of MXene and the ultraviolet stability of PDA, the heating performance of the fabric in a complex environment is significantly improved.

[0065] III. Environmentally Friendly and Safe, Meeting the Requirements of Sustainable Development 1. Green Flame Retardant Materials: Both MXene and PDA are non-toxic materials, avoiding the environmental pollution and toxicity hazards of traditional halogen-based flame retardants; The process does not require high temperature or organic solvents, meeting the requirements of green environmental protection.

[0066] 2. Advantages and Effects: Suitable for close-fitting wear or children's products, with high safety; No harmful gas is released, and it has no negative impact on the environment and health during use.

[0067] 3. Principle Analysis: By selecting green materials and processes, the problems of traditional flame retardants in environmental protection and health safety are solved.

[0068] IV. Simple Preparation Process, Suitable for Large-scale Production 1. Layer-by-layer Self-assembly Technology: The low-temperature electrostatic adsorption technology is adopted to achieve uniform coating of MXene and PDA on the fabric surface; 2. Process Controllability: By adjusting the number of deposition layers and the solution concentration, the coating thickness and functionality can be flexibly adjusted.

[0069] 3. Advantages and Effects: The process flow is simple, the cost is low, and it is suitable for large-scale industrial production; The coating has strong adhesion and high durability, suitable for frequent use scenarios.

[0070] 4. Principle Analysis: The electrostatic adsorption property of the self-assembly technology ensures the uniformity and adhesion of the coating, while simplifying the complex process of traditional processes.

[0071] V. Coexisting Comfort and Durability, Expanding Application Scenarios 1. Excellent Softness and Breathability: With cotton fabric as the substrate, the softness and breathability of the fabric are maintained; The coating is thin and uniform, without affecting the comfortable wearing performance of the fabric.

[0072] 2. Advantages and Effects: The product combines functionality and comfort, meeting the requirements of various scenarios such as smart clothing and safety protection; High durability extends the service life of the product, reducing the replacement frequency and usage cost.

[0073] 3. Principle Analysis: The combination of a soft cotton fabric substrate and a highly adhesive coating achieves a good balance between functionality and user experience in the present invention.

[0074] Although the present disclosure is disclosed as above, the scope of protection of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will all fall within the scope of protection of the present invention.

Claims

1. A cotton fabric with the combined functions of radiant heating and flame retardancy, characterized in that, It includes a substrate and at least two composite layer units laminated and coated on the substrate, and each of the composite layer units includes a PDA layer and an MXene layer coated on the PDA layer.

2. The cotton fabric according to claim 1, characterized in that, A top PDA layer is also coated on the composite layer unit.

3. A method for preparing a cotton fabric as described in claim 1, characterized in that, The preparation method specifically includes the following steps: S1. Prepare a dopamine solution with a concentration of 1 - 2 mg / mL. S2. Prepare an MXene dispersion with a concentration of 1 - 2 mg / ml. S3. Adopt the dopamine self-polymerization method, immerse the substrate into the dopamine solution prepared in step S1, and then adopt the hydrogen bond and electrostatic force adsorption method to immerse it into the MXene dispersion prepared in step S2 to complete the deposition of one composite layer unit. S4. According to the number of pre-designed composite layer units, repeat step S3 to finally obtain a flame-retardant cotton fabric.

4. The preparation method according to claim 3, characterized in that, The specific operation of step S1 is as follows: Dissolve dopamine in a Tris-base buffer solution, and the concentration of the Tris-base buffer solution is 10 mM and the pH is 8.

5.

5. The preparation method according to claim 3, characterized in that, The specific operation of step S2 is as follows: Add Ti3AlC2 powder into a hydrofluoric acid solution with a concentration of 10 - 30%, stir at room temperature for 24 hours to remove Al atoms to obtain Ti3C2Tx, ultrasonically treat for 1 hour, and then centrifuge and wash the product with deionized water multiple times until the pH value of the solution is close to neutral.

6. The preparation method according to claim 3, characterized in that, The substrate in step S3 is a cotton fabric substrate, and the cotton fabric substrate is pretreated. The pretreatment steps are as follows: Wash the cotton fabric substrate with deionized water and ethanol, remove surface impurities and grease, and then place it in an oven at 55 - 65°C for drying for 2 - 3 h.

7. The preparation method according to claim 6, characterized in that, In step S3, the specific steps of adopting the dopamine self-polymerization method and the hydrogen bond and electrostatic force adsorption method are as follows: Immerse the pretreated cotton fabric substrate into the dopamine solution prepared in step S1, keep it for 5 - 10 min, take it out and press dry most of the liquid, and dry it at 55 - 65°C for 10 - 15 min. Then immerse it into the MXene dispersion prepared in step S2, keep it for 5 - 10 min, take it out and press dry most of the liquid, and dry it at 55 - 65°C for 10 - 15 min.

8. The preparation method according to claim 3, wherein It also includes step S5. Adopt the electrostatic adsorption method, immerse the obtained cotton fabric into the dopamine solution prepared in step S1 to obtain a cotton fabric containing a top PDA layer.