A flexible transparent composite material and a preparation method and application thereof

Abstract

The application provides a flexible transparent composite material and a preparation method and application thereof, relates to a multi-component composite material in the field of electromagnetic functional materials. The application utilizes the characteristics of high conductivity and high length-diameter ratio of silver nanowires, and combines MXene materials with excellent electromagnetic properties, to prepare an electromagnetic shielding composite material with certain mechanical properties, high light transmittance and good flexibility. The material will have broad development space under the background of huge market demand. The application can prepare a high-performance flexible transparent electromagnetic shielding AgNW / MXene / PDMS film through simple chemical reaction and precise spraying process. The application can effectively control the network structure of AgNW and regulate the shielding performance of the composite material, thereby being beneficial to industrial production, and having important significance for the development and wide application of electromagnetic shielding materials.

Description

Technical Field

[0001] This invention relates to multi-component composite materials in the field of electromagnetic functional materials, specifically to a flexible transparent composite material, its preparation method, and its application. Background Technology

[0002] In today's society, with the continuous expansion of electromagnetic technology applications, electromagnetic interference (EMI) problems are becoming increasingly serious, posing a threat to the performance of electronic devices, system safety, and human health. Especially with the advent of the 5G era, the trend towards higher frequencies and smaller sizes in electronic devices has made EMI problems even more prominent. In the fields of visual windows, transparent wearable devices, and aerospace equipment, flexibility and transparency have become performance requirements for EMI shielding materials. Transparent and conductive films need to possess satisfactory EMI shielding performance to meet the needs of practical applications; high-performance EMI shielding films require high conductivity and reasonable optical transparency. Traditional indium tin oxide (ITO) is widely used in industrial production due to its balanced conductivity and optical transparency. However, its inherent mechanical brittleness, low manufacturing efficiency, and high cost limit its application in flexible wearable devices and smart detection fields. Therefore, the development of flexible transparent electromagnetic shielding materials is of great significance to modern society. These materials can not only meet the needs of electronic devices for visual effects and portability, improving user experience, but also provide effective electromagnetic interference protection without affecting the appearance and visual clarity of the device. The low power consumption and high efficiency characteristics of these materials help reduce energy consumption and support sustainable development goals. Meanwhile, their high performance and reliability are also crucial for national security and military technology, ensuring the normal operation of communication equipment and radar systems and enhancing information security. Therefore, increasing investment in the research and development of flexible transparent electromagnetic shielding materials and promoting their technological advancement is of great significance for promoting social progress and sustainable development.

[0003] To date, various conductive alternatives have been reported, including carbon nanotubes (CNTs), metal nanowires, graphene, and transition metal carbide / carbonitride (MXene) sheets. While graphene and carbon nanotubes possess high transparency and good electromagnetic shielding properties, their filler content affects transparency when meeting EMI SE requirements. Metals such as copper (Cu) are widely used due to their good conductivity and shielding effectiveness, but they suffer from several limitations, such as visual obstruction, difficulty in use in small-scale applications, and continuity issues in the manufacturing process, all of which restrict their applications. Silver nanowires (AgNWs) have proven to be promising materials for fabricating transparent and reliable conductors due to their excellent aspect ratio, good electrical conductivity, and excellent mechanical flexibility. In recent years, AgNW-based conductors have been widely used in fields including flexible fuel cells, stretchable and transparent supercapacitors, transparent sensors, air filters, color-changing soft robots, and flexible transparent electromagnetic interference shielding films. MXenes are a class of two-dimensional materials, typically composed of transition metal carbides. Their structural basis consists of hexagonal layers formed by transition metals and carbon or nitrogen. Due to this unique composition, MXenes possess excellent electromagnetic and mechanical properties, along with extremely large specific surface area, high plasticity, and flexibility. Therefore, they are widely used in the manufacture of conductive inks, flexible electrodes, and transparent conductive films. However, randomly distributed silver nanowires often suffer from low transmittance, high haze, and significant contact resistance, with conductivity often decreasing sharply under tension. Therefore, reducing the contact resistance of silver nanowires while maintaining both transmittance and conductivity is crucial for improving the overall performance of the material. Summary of the Invention

[0004] This invention is made to solve the above-mentioned problems, and aims to provide a flexible transparent composite material, its preparation method and application.

[0005] This invention provides a method for preparing a flexible transparent composite material, characterized by the following steps: S10, preparing a transparent hydrophobic PDMS film, an AgNW dispersion, and a solution of MXene made of Ti3C2 material, wherein the average aspect ratio of AgNW is approximately 500; S20, spraying the AgNW dispersion onto the PDMS film, followed by heating to obtain an AgNW / PDMS film; S30, spraying the MXene solution onto the AgNW / PDMS film to obtain an MXene / AgNW / PDMS film; S40, coating another layer of PDMS onto the MXene / AgNW / PDMS film, designating the newly coated PDMS layer as the upper film, and then drying it to transfer the MXene / AgNW component from the MXene / AgNW / PDMS film to the upper film; S50, peeling off the upper film, the peeled portion being the AgNW / MXene / PDMS film, which is the flexible transparent composite material.

[0006] The method for preparing the flexible transparent composite material provided by the present invention may also have the following features: step S10 includes the following sub-steps: S11, preparing a transparent hydrophobic PDMS film: PDMS is mixed with a curing agent and then vacuum-treated, then mixed with n-hexane and coated onto a substrate, dried and cleaned, and finally modified with 1H,1H,2H,2H-perfluorodecyltrichlorosilane to obtain a PDMS film; S12, preparing an AgNW dispersion: PVP is dissolved in ethylene glycol, and AgNW is prepared by hydrothermal reaction after adding metal salt solution and silver nitrate solution, and then dispersed in isopropanol or ethanol after centrifugation to obtain an AgNW dispersion; S13, preparing a Ti3C2 material MXene solution: Ti3C2 material MXene solution is prepared by etching Ti3AlC2 with HCl / LiF mixed solution.

[0007] The method for preparing flexible transparent composite material provided by the present invention may also have the following features: in step S11, the mass of PDMS is recorded as m1, the mass of curing agent is recorded as m2, the mass of n-hexane is recorded as m3, m1:m2=(8~12):1, (m1+m2):m3=1:(3~6), and the modification operation is carried out in a vacuum heating and drying environment.

[0008] The method for preparing the flexible transparent composite material provided by the present invention may also have the following features: in step S12, the molecular weight of PVP is 900,000 to 1,400,000, the metal salt includes any one or more of sodium chloride, ferric chloride or copper chloride, and in the ethylene glycol solution during the hydrothermal reaction, the mass ratio of metal salt, PVP and silver nitrate is (0.004 to 0.008):(2 to 4):1, and the concentration of silver nitrate is 0.1 to 0.15 mol / L.

[0009] The method for preparing the flexible transparent composite material provided by the present invention may also have the following characteristics: the heating rate of the hydrothermal reaction is 5℃ / min to 10℃ / min, the reaction temperature is 140℃ to 170℃, and the holding time is 6h to 10h.

[0010] The method for preparing the flexible transparent composite material provided by the present invention may also have the following feature: wherein the concentration of MXene in the MXene solution is 0.2 mg / mL to 0.4 mg / mL.

[0011] The method for preparing the flexible transparent composite material provided by the present invention may also have the following features: in step S20 and / or step S30, the nozzle diameter of the spray gun during spraying is 0.2 mm to 0.5 mm, the spraying pressure is 2 bar to 5 bar, and the spraying distance is 8 to 15 cm.

[0012] The method for preparing flexible transparent composite material provided by the present invention may also have the following features: in step S40, the coated PDMS contains a curing agent mixed in a mass ratio of (8-12):1, and is subjected to vacuum treatment before drying.

[0013] The present invention also provides a flexible transparent composite material, characterized in that it is prepared by any of the methods described above for preparing flexible transparent composite materials.

[0014] The present invention also provides an application of a flexible transparent composite material in electromagnetic shielding, characterized in that the shielding performance of the flexible transparent composite material is 10-40 dB and the light transmittance of the flexible transparent composite material is 70%-85%.

[0015] The role and effect of invention

[0016] This invention utilizes the high conductivity and high aspect ratio of silver nanowires, combined with MXene material possessing excellent electromagnetic properties, to prepare an electromagnetic shielding composite material with certain mechanical properties, high light transmittance, and good flexibility. Given the current market demand, this material has broad development prospects.

[0017] This invention enables the preparation of high-performance, flexible, transparent electromagnetic shielding AgNW / MXene / PDMS films through a simple chemical reaction and precise spraying process. This invention effectively controls the network structure of AgNW and modulates the shielding performance of the composite material, thus facilitating industrial production and holding significant importance for the development and widespread application of electromagnetic shielding materials. Attached Figure Description

[0018] Figure 1This is a flowchart illustrating a method for preparing a flexible transparent composite material according to an embodiment of the present invention.

[0019] Figure 2 These are SEM images of the sample, control sample 1, and control sample 2 in the test examples of this invention, magnified at 400×.

[0020] Figure 3 This is a comparison of the transmittance spectra and physical samples of the sample, control sample 1, and control sample 2 in the test examples of this invention;

[0021] Figure 4 These are the EMI performance curves of the sample, control sample 1, and control sample 2 in the test examples of this invention. Detailed Implementation

[0022] To make the technical means, creative features, objectives and effects of this invention easy to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate a flexible transparent composite material of this invention, its preparation method and application.

[0023] <Example>

[0024] Figure 1 This is a flowchart illustrating a method for preparing a flexible transparent composite material according to an embodiment of the present invention.

[0025] like Figure 1 As shown, this embodiment provides a method for preparing a flexible transparent composite material, including the following steps:

[0026] S10, prepare transparent hydrophobic PDMS films, AgNW dispersions, and Ti3C2 MXene solutions, respectively, including the following sub-steps:

[0027] S11, Preparation of a transparent hydrophobic PDMS film:

[0028] (1) Mix PDMS and curing agent at a mass ratio of 10:1 and vacuum for 30 min. Then mix the mixture with n-hexane at a mass ratio of 1:5. After preparation, coat it onto a clean glass substrate and place it in an oven at 80℃ for 3 h.

[0029] (2) The film on the glass substrate was cleaned by a plasma cleaner and then modified by 1H,1H,2H,2H-perfluorodecyltrichlorosilane in a vacuum dryer at 80°C for 3 hours to finally obtain a transparent hydrophobic PDMS film.

[0030] S12, to prepare a dispersion of AgNW with an average aspect ratio of approximately 500:

[0031] (1) Dissolve 1.6g of PVP with a molecular weight of 1,000,000 in ethylene glycol, add 1.6mL of 1.2mg / mL NaCl solution, and then add 0.5g of AgNO3.

[0032] (2) Silver nanowires were prepared by hydrothermal method at 160℃. Then deionized water was added and pure silver nanowires were obtained by centrifugation. The prepared silver nanowires were dispersed in isopropanol or ethanol to prepare a 0.5 mg / mL AgNW dispersion.

[0033] S13, Preparation of MXene solution from Ti3C2 material:

[0034] A 0.2 mg / mL MXene solution was prepared by etching Ti3AlC2 with a mixed solution of HCl / LiF.

[0035] S20, Preparation of AgNW / PDMS thin films:

[0036] (1) Place the transparent hydrophobic PDMS film with glass substrate prepared in step S11 on a 40°C heating stage, and then take 5 mL of AgNW dispersion prepared in step S12 and add it to a spray bottle with a spray gun (spray gun needle orifice size is 0.4 mm, spraying pressure is 3 bar, spraying distance is 10 cm). Use the spray gun to uniformly spray the AgNW dispersion onto the surface of the PDMS film.

[0037] (2) Heat the heating table to 100°C and heat-treat for 5 minutes to obtain AgNW / PDMS film.

[0038] S30, Preparation of MXene / AgNW / PDMS thin films:

[0039] Take 3 mL of MXene solution and spray it onto the AgNW / PDMS film using a spray gun (spray gun needle orifice size of 0.4 mm, spraying pressure of 3 bar, spraying distance of 10 cm) to obtain MXene / AgNW / PDMS film.

[0040] S40, Transfer:

[0041] A mixture of PDMS and curing agent in a mass ratio of 10:1 was coated onto the MXene / AgNW / PDMS film. The newly coated PDMS layer was designated as the upper film. The film was then vacuum-treated for 30 minutes and kept in an 80°C oven for 3 hours to allow the MXene / AgNW component in the MXene / AgNW / PDMS film to transfer to the upper film.

[0042] S50, to obtain flexible transparent composite materials:

[0043] Peel off the top film; the peeled-off portion is an AgNW / MXene / PDMS film, which is a flexible transparent composite material.

[0044] This embodiment also provides a flexible transparent composite material, which is prepared by a method for preparing a flexible transparent composite material provided in this embodiment.

[0045] <Comparative Example 1>

[0046] This comparative example refers to steps S10, S20, S40, and S50 of the method for preparing a flexible transparent composite material provided in the embodiment, and prepares an AgNW / PDMS composite material with a micro-network structure as a comparison.

[0047] The preparation method of the AgNW / PDMS composite material with micronetwork structure in this comparative example includes the following steps:

[0048] Step S1 involves preparing a transparent hydrophobic PDMS film and an AgNW dispersion, which specifically includes the following sub-steps:

[0049] Step S1-1: Prepare a transparent hydrophobic PDMS film. This step is the same as step S11 in the example and will not be repeated.

[0050] Step S1-2, prepare the AgNW dispersion:

[0051] (1) Dissolve 1.6g of PVP with a molecular weight of 9,000,000 in ethylene glycol, add 1.6mL of FeCl3 solution with a concentration of 1.2mg / mL, and then add 0.5g of AgNO3.

[0052] (2) Silver nanowires were prepared by hydrothermal method at 150℃. The prepared silver nanowires were dispersed in isopropanol or ethanol to prepare a 0.5 mg / mL AgNW dispersion.

[0053] Step S2, preparation of AgNW / PDMS thin film:

[0054] (1) Place the transparent hydrophobic PDMS film with glass substrate prepared in step S1-1 on a 40°C heating stage, and then take 5 mL of AgNW dispersion prepared in step S1-2 and add it to a spray bottle with a spray gun (spray gun needle orifice size is 0.3 mm, spraying pressure is 2 bar, spraying distance is 10 cm). Use the spray gun to uniformly spray the AgNW dispersion onto the surface of the PDMS film.

[0055] (2) Heat the heating table to 100°C and heat-treat for 5 minutes to obtain AgNW / PDMS film.

[0056] To reflect the control variables, this comparative example also includes steps S3 and S4, which are used to reflect the operation of transferring silver nanowires from the AgNW / PDMS film to the newly coated PDMS.

[0057] Step S3, Transfer: A mixture of PDMS and curing agent in a mass ratio of 10:1 is coated onto the AgNW / PDMS film obtained in step S2. The newly coated PDMS layer is referred to as the upper film. Then, vacuum treatment is performed for 30 minutes and the film is kept in an oven at 80°C for 3 hours to transfer the AgNW component in the AgNW / PDMS film to the upper film.

[0058] Step S4, obtaining the AgNW / PDMS composite material with a micro-network structure: peel off the upper film, the peeled part is the AgNW / PDMS film, which is the AgNW / PDMS composite material with a micro-network structure of this comparative example.

[0059] <Comparative Example 2>

[0060] This comparative example refers to steps S10, S20, S40, and S50 of the method for preparing a flexible transparent composite material provided in the embodiment, and prepares an AgNW / PDMS composite material without a micronetwork structure as a comparison.

[0061] The preparation method of the AgNW / PDMS composite material without micronetwork structure in this comparative example includes the following steps:

[0062] Step S1' involves preparing a transparent hydrophobic PDMS film and an AgNW dispersion, which specifically includes the following sub-steps:

[0063] Step S1-1': Prepare a transparent hydrophobic PDMS film. This step is the same as step S11 in the example and will not be repeated.

[0064] Step S1-2', Prepare a dispersion of AgNW:

[0065] (1) Dissolve 1.6g of PVP with a molecular weight of 1,200,000 in ethylene glycol, add 1.6mL of CuCl2 solution with a concentration of 1.2mg / mL, and then add 0.5g of AgNO3.

[0066] (2) Silver nanowires were prepared by hydrothermal method at 170℃. The prepared silver nanowires were dispersed in isopropanol or ethanol to prepare a 0.5 mg / mL AgNW dispersion.

[0067] Step S2', Preparation of AgNW / PDMS thin film:

[0068] The transparent hydrophobic PDMS film with a glass substrate prepared in step S1-1' was placed on a 40°C heating stage. Then, 5 mL of AgNW dispersion prepared in step S1-2' was added to a spray bottle equipped with a spray gun (spray gun needle orifice size of 0.3 mm, spraying pressure of 2 bar, spraying distance of 10 cm). The AgNW dispersion was uniformly sprayed onto the surface of the PDMS film using the spray gun to obtain an AgNW / PDMS film.

[0069] To reflect the control variables, this comparative example also includes steps S3' and S4', which are used to reflect the operation of transferring silver nanowires from the AgNW / PDMS film to the newly coated PDMS.

[0070] Step S3', Transfer: A mixture of PDMS and curing agent in a mass ratio of 10:1 is coated onto the AgNW / PDMS film obtained in step S2'. The newly coated PDMS layer is referred to as the upper film. Then, vacuum treatment is performed for 30 minutes and the film is kept in an oven at 80°C for 3 hours to transfer the AgNW component in the AgNW / PDMS film to the upper film.

[0071] Step S4': Obtain the AgNW / PDMS composite material without micronetwork structure: peel off the upper film. The peeled part is the AgNW / PDMS film, which is the AgNW / PDMS composite material without micronetwork structure in this comparative example.

[0072] <Test Example>

[0073] The flexible transparent composite material in the examples is referred to as the sample, the AgNW / PDMS composite material with micro-network structure in Comparative Example 1 is referred to as Control Sample 1, and the AgNW / PDMS composite material without micro-network structure in Comparative Example 2 is referred to as Control Sample 2.

[0074] This test case demonstrates the application of a flexible transparent composite material in electromagnetic shielding by conducting corresponding tests on the sample, control sample 1, and control sample 2.

[0075] Figure 2 These are SEM images of the sample, control sample 1, and control sample 2 in the test examples of this invention, magnified at 400×.

[0076] like Figure 2As shown, (1) For control sample 1, a clear silver nanowire micro-network structure can be observed. Each micro-network of silver nanowires is composed of multiple silver nanowires. This maximizes the high conductivity of silver nanowires. In addition, the heat treatment further reduces the contact resistance between silver nanowires. At the same time, a large number of pores can be observed around the silver nanowires. The presence of these pores can greatly reduce the haze caused by the random distribution of silver nanowires and improve the overall transparency of the material. (2) For the sample, dark MXene nanosheets can be observed around the silver nanowire micro-network structure. MXene mainly adheres to the silver nanowires and does not fill the pores. This minimizes the influence of the presence of MXene nanosheets on the light transmittance of the material. In addition, the adhesion to the silver nanowires can further improve the overall conductivity of the material. (3) For control sample 2, the silver nanowires can be observed to be randomly distributed. Therefore, compared with control sample 2 prepared in comparative example 2, the sample prepared in the example has a more regular arrangement.

[0077] Figure 3 This is a comparison of the transmittance spectra and physical samples of the sample, control sample 1, and control sample 2 in the test examples of this invention.

[0078] like Figure 3 As shown, (1) the transmittance spectrum shows that for control sample 1, the overall transmittance of the material is about 80%, while for the sample with added MXene, the overall transmittance of the material is about 76%. It can be seen that the addition of MXene has no significant effect on the transmittance of the sample prepared in the example. For control sample 2, the overall transmittance of the material is about 67%, which is lower than that of control sample 1 and the sample prepared in the example. Therefore, the overall transmittance of the material with micro-mesh structure is higher. (2) For control sample 1, it can be observed that the material itself has high transmittance, forming a contrast with the surrounding paper, and has low haze; (3) For the sample, it can be observed that although the transmittance of the material itself is lower than that of control sample 1, it still has high transmittance, and at the same time, the transmittance of the material itself is lower than that of control sample 1. Figure 3 As can be seen from the upper right corner of Figure b in the figure, the sample prepared in the example has high flexibility; (4) For control sample 2, it can be observed that although the light transmittance of the material is still acceptable, there is obvious haze, and the pattern on the paper under the material has obvious blurring. Therefore, compared with control sample 2 prepared in comparative example 2, the sample prepared in the example has higher light transmittance and lower haze.

[0079] In this test example, the sample, control sample 1, and control sample 2 were cut into square specimens of 2.2×1.1×0.4cm, and then the electromagnetic parameters of the three specimens were measured using a vector network analyzer in the frequency range of 8.2GHz to 12.4GHz.

[0080] The electromagnetic shielding performance of the material mainly comes from the silver nanowire micronetwork structure within it. This structure significantly reduces the contact resistance between the silver nanowires, thereby improving the overall conductivity of the material. Furthermore, MXene possesses excellent electrical conductivity, and the selective attachment of MXene to the silver nanowire network further enhances the material's conductivity while maintaining its light transmittance.

[0081] Figure 4 These are the EMI performance curves of the sample, control sample 1, and control sample 2 in the test examples of this invention.

[0082] like Figure 4 As shown, the shielding performance of the sample, control sample 1, and control sample 2 were 30.2 dB, 24.7 dB, and 10.3 dB, respectively. Therefore, compared with the shielding performance of control sample 2 (10.3 dB), the sample prepared in the examples and control sample 1 prepared in comparative example 1 both achieved excellent shielding performance, which is sufficient to prove that the silver nanowire network with micromesh structure can significantly improve the overall conductivity of the material; and the addition of a trace amount of MXene nanomaterial to control sample 1 can significantly improve the overall conductivity of the material, giving it excellent electromagnetic shielding performance.

[0083] Those skilled in the art should understand that this invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a flexible transparent composite material, characterized in that, Includes the following steps: S10, transparent hydrophobic PDMS film, AgNW dispersion and Ti3C2 material MXene solution were prepared respectively, wherein the average aspect ratio of AgNW is about 500. S20, the AgNW dispersion is sprayed onto the PDMS film, and then heated to obtain an AgNW / PDMS film; S30, the MXene solution is sprayed onto the AgNW / PDMS film to obtain the MXene / AgNW / PDMS film; S40, a new layer of PDMS is coated on the MXene / AgNW / PDMS film, and the newly coated PDMS layer is referred to as the upper film. Then, it is dried so that the MXene / AgNW component in the MXene / AgNW / PDMS film is transferred to the upper film. S50, peel off the upper film. The peeled portion is an AgNW / MXene / PDMS film, which is the flexible transparent composite material. Step S10 includes the following sub-steps: S11, Preparation of transparent hydrophobic PDMS film: PDMS is mixed with curing agent and then vacuum treated, then mixed with n-hexane and coated onto substrate, dried and cleaned, and finally modified with 1H,1H,2H,2H-perfluorodecyltrichlorosilane to obtain the PDMS film. S12, Preparation of AgNW dispersion: PVP is dissolved in ethylene glycol, and AgNW is prepared by hydrothermal reaction after adding metal salt solution and silver nitrate solution. After centrifugation, AgNW is dispersed in isopropanol or ethanol to obtain the AgNW dispersion. S13, Preparation of MXene solution of Ti3C2 material: The MXene solution of Ti3C2 material is prepared by etching Ti3AlC2 with HCl / LiF mixed solution.

2. The method for preparing the flexible transparent composite material according to claim 1, characterized in that: in, In step S11, the mass of PDMS is recorded as m1, the mass of the curing agent as m2, and the mass of n-hexane as m3. m1:m2=(8~12):1,(m1+m2):m3=1:(3~6), The modification process was carried out in a vacuum heating and drying environment.

3. The method for preparing the flexible transparent composite material according to claim 1, characterized in that: in, In step S12, the molecular weight of PVP is 900,000 to 1,400,000. The metal salt includes any one or more of sodium chloride, ferric chloride, or copper chloride. In the ethylene glycol solution during the hydrothermal reaction, the mass ratio of metal salt, PVP, and silver nitrate is (0.004–0.008):(2–4):1, and the concentration of silver nitrate is 0.1–0.15 mol / L.

4. The method for preparing the flexible transparent composite material according to claim 1 or 3, characterized in that: in, The heating rate of the hydrothermal reaction is 5℃ / min to 10℃ / min, the reaction temperature is 140℃ to 170℃, and the holding time is 6h to 10h.

5. The method for preparing the flexible transparent composite material according to claim 1, characterized in that: in, The concentration of MXene in the MXene solution is 0.2 mg / mL to 0.4 mg / mL.

6. The method for preparing the flexible transparent composite material according to claim 1, characterized in that: in, In step S20 and / or step S30, the nozzle diameter of the spray gun during spraying is 0.2mm to 0.5mm, the spraying pressure is 2bar to 5bar, and the spraying distance is 8 to 15cm.

7. The method for preparing the flexible transparent composite material according to claim 1, characterized in that: in, In step S40, the coated PDMS contains a curing agent mixed in a mass ratio of (8-12):

1. Vacuum treatment is performed before drying.

8. A flexible transparent composite material, characterized in that, It is prepared by the method for preparing the flexible transparent composite material according to any one of claims 1 to 7.

9. The application of the flexible transparent composite material as described in claim 8 in electromagnetic shielding, in, The shielding performance of the flexible transparent composite material is 10–40 dB. The light transmittance of the flexible transparent composite material is 70% to 85%.

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