Functional graphene membranes and methods of making the same

Abstract

This invention provides a functional graphene film and its preparation method, comprising: preparing an aqueous graphene oxide slurry according to requirements; applying the aqueous graphene oxide slurry to a substrate at least twice using a screen printing machine; heating the substrate coated with the aqueous graphene oxide slurry to obtain a graphene oxide film, and peeling the graphene oxide film off the substrate; and subjecting the graphene oxide film to thermal reduction, graphitization, and calendering treatments to obtain a functional graphene film. To balance heat dissipation and flexibility to meet the requirements of electronic devices, screen printing technology is introduced into the preparation process of the functional graphene film. Due to the presence of the screen, air bubbles form at the locations of the screen between the two layers of graphene oxide film during heating. This air bubble structure effectively buffers wrinkles caused by bending when the final functional graphene film is bent, thus exhibiting a certain degree of flexibility.

Description

Technical Field

[0001] This invention belongs to the field of graphene technology, specifically relating to a functional graphene film and its preparation method. Background Technology

[0002] This section provides only background information relevant to this disclosure and is not necessarily prior art.

[0003] With the arrival of the 5G era, high-configuration mobile phones, computers, and other electronic products are emerging in large numbers. However, high configuration does not necessarily mean smooth operation. Without a good heat dissipation mechanism, the continuous and stable operation of electronic products cannot be guaranteed. Among them, the core components of electronic components have their own stable operating temperature range. Generally speaking, if the temperature increases by 8°C to 10°C, the lifespan of electronic components will be reduced by half. Therefore, the application of heat dissipation films in electronic products can effectively prevent problems such as malfunction due to localized overheating.

[0004] Heat dissipation films are commonly used heat dissipation materials in high-power communication equipment. Among them, graphene is one of the most widely used materials. Due to its outstanding heat dissipation performance and advantages such as high temperature resistance and corrosion resistance, it has great potential for local heat dissipation in electronic products. Macroscopically assembled graphene oxide films are an important application of nanoscale graphene. Common preparation methods include vacuum filtration, film cutting, spin coating, spraying, and dip coating.

[0005] However, in existing macroscopic thin film materials, high heat dissipation and high flexibility are contradictory and often difficult to achieve simultaneously. The stretchability of graphene micro-folds allows it to withstand repeated folding, knotting, twisting, bending, and origami-like deformations, making it more suitable for various electronic products. However, currently prepared graphene films lack micro-crease or even seamless folding properties, limiting their application in easily bent and compressed devices. In 2016, Professor Shi Gaoquan created numerous large folds on the surface of graphene heat dissipation films using a macroscopic template assembly method; however, its imperfect elasticity could not meet the demands of rapid technological development. Furthermore, the inadequacy of the film structure design makes its flexibility unclear, limiting its application in flexible devices. In 2017, Professor Gao Chao proposed the idea of ​​"large-area micro-folds," achieving high heat dissipation through large-diameter graphene with fewer defects, while utilizing micro-folds to provide sufficient strain space during stretching and bending, ensuring its flexibility. Therefore, using various physicochemical methods to achieve both high heat dissipation and high flexibility has become an inevitable trend in current technological development. Summary of the Invention

[0006] In view of the above problems, a first aspect of the present invention provides a method for preparing a functional graphene film, comprising:

[0007] Configure graphene oxide aqueous slurry according to requirements;

[0008] The aqueous graphene oxide slurry is applied to the substrate at least twice using a screen printing machine.

[0009] The substrate coated with the aqueous slurry of graphene oxide is heated to obtain a graphene oxide film, and the graphene oxide film is peeled off from the substrate.

[0010] The graphene oxide film is subjected to thermal reduction, graphitization, and calendering to obtain a functional graphene film.

[0011] To balance heat dissipation and flexibility to meet the needs of electronic devices, screen printing technology was introduced into the preparation of functional graphene films. This allows for precise control of the thickness and morphology of the print each time, and the process is simple and easy to operate. A screen printing machine is used to coat the substrate with an aqueous graphene oxide slurry at least twice. Due to the presence of the screen, air bubbles form between the two layers of graphene oxide film during heating. This air bubble structure effectively buffers wrinkles caused by bending when the final functional graphene film is folded, giving it a certain degree of flexibility. This allows it to withstand repeated folding, knotting, twisting, bending, and other complex deformations, making it more suitable for various electronic products.

[0012] In some embodiments of the present invention, the step of applying the graphene oxide aqueous slurry to the substrate at least twice using a screen printing machine includes:

[0013] Determine the required number of coating passes based on the desired thickness;

[0014] The graphene oxide aqueous slurry is added to one end of the screen printing plate of the screen printing machine. Pressure is applied to the graphene oxide aqueous slurry by a squeegee to move it toward the other end of the screen printing plate, thus completing one coating on the substrate. The above process is repeated according to the required number of coatings.

[0015] In some embodiments of the present invention, the coating angle of the doctor blade is 40°-60° and the coating speed is 4-8m / min.

[0016] In some embodiments of the present invention, the scraper is a polyurethane flat-edged scraper.

[0017] In some embodiments of the present invention, the screen printing plate has a mesh count of 200-600.

[0018] In some embodiments of the present invention, the screen printing plate is made of nylon.

[0019] In some embodiments of the present invention, the step of configuring the graphene oxide aqueous slurry as needed includes:

[0020] Select the appropriate model of graphene oxide according to your needs;

[0021] The graphene oxide was added to deionized water to prepare an aqueous solution of graphene oxide.

[0022] The graphene oxide was uniformly dispersed in the deionized water by stirring and ultrasonication to obtain the graphene oxide aqueous slurry.

[0023] In some embodiments of the present invention, the mass fraction of the aqueous graphene oxide solution is 1%-4%.

[0024] In some embodiments of the present invention, the temperature range of the thermal reduction is 100℃-10000℃, and the temperature range of the graphitization is 2000℃-3000℃.

[0025] In some embodiments of the present invention, the substrate coated with the aqueous graphene oxide slurry is heated by a hair dryer or an infrared lamp, and the heating temperature range is 30°C-90°C.

[0026] A second aspect of the present invention provides a functional graphene film, obtained by the preparation method of the functional graphene film in any of the above-described technical solutions, comprising at least two graphene layers, wherein a bubble structure is disposed between adjacent graphene layers.

[0027] The functional graphene film of this invention has the same beneficial effects as the functional graphene film prepared by the preparation method of any of the above-mentioned technical solutions, and will not be repeated here. Attached Figure Description

[0028] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0029] Figure 1 This is a flowchart illustrating the preparation method of the functional graphene film according to an embodiment of the present invention;

[0030] Figure 2 A cross-sectional schematic diagram and a bending schematic diagram of the functional graphene film prepared by the preparation method of the functional graphene film in this embodiment of the invention.

[0031] Figure 3(a) is an image of the functional graphene film prepared by the method of the present invention without bending.

[0032] Figure 3(b) is an image of the functional graphene film shown in Figure 3(a) after bending;

[0033] Figure 3(c) shows an image of a graphene heat dissipation film produced using the scraping method in the prior art;

[0034] Figure 3(d) is an image of the graphene heat dissipation film shown in Figure 3(c) after bending;

[0035] Figure 4 This is a microscope image of the surface of the functional graphene film prepared in Example 1 of the present invention;

[0036] Figure 5 This is a microscope image of the functional graphene film prepared in Example 1 of the present invention after 100,000 bending cycles.

[0037] Figure 6 This is a scanning electron microscope cross-sectional view of the functional graphene film prepared in Example 1 of the present invention without bending.

[0038] Figure 7 This is a scanning electron microscope cross-sectional image of the functional graphene film prepared in Example 1 of the present invention after 100,000 bending cycles.

[0039] Figure 8 This is a microscope image of the surface of the functional graphene film prepared in Example 2 of the present invention;

[0040] Figure 9 This is a microscope image of the functional graphene film prepared in Example 2 of the present invention after 100,000 bending cycles.

[0041] Figure 10 This is a microscope image of the surface of the functional graphene film prepared in Example 3 of the present invention;

[0042] Figure 11 This is a microscope image of the functional graphene film prepared in Example 3 of the present invention after 100,000 bending cycles.

[0043] Figure 12 This is a microscope image of the surface of the functional graphene film prepared in Example 4 of the present invention;

[0044] Figure 13 This is a microscope image of the functional graphene film prepared in Example 4 of the present invention after 100,000 bending cycles. Detailed Implementation

[0045] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0046] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also mean including the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof.

[0047] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0048] For ease of description, spatial relative terms may be used in the text to describe the relationship of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "over," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure is flipped, an element described as "below other elements or features" or "below other elements or features" would subsequently be oriented as "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0049] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0050] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0051] like Figure 1 , Figures 3(a) to 3(d) As shown, the first aspect of the present invention provides a method for preparing a functional graphene film, comprising:

[0052] Configure graphene oxide aqueous slurry according to requirements;

[0053] At least two coats of graphene oxide aqueous slurry are applied to the substrate using a screen printing machine.

[0054] A substrate coated with an aqueous slurry of graphene oxide is heated to obtain a graphene oxide film, and the graphene oxide film is then peeled off from the substrate.

[0055] Functional graphene films were obtained by thermal reduction, graphitization, and calendering of graphene oxide films.

[0056] To balance heat dissipation and flexibility to meet the needs of electronic devices, screen printing technology was introduced into the preparation of functional graphene films. This allows for precise control of the thickness and morphology of the print each time, and the process is simple and easy to operate. A screen printing machine is used to coat the substrate with an aqueous graphene oxide slurry at least twice. Due to the presence of the screen, air bubbles form between the two layers of graphene oxide film during heating. This air bubble structure effectively buffers wrinkles caused by bending when the final functional graphene film is folded, giving it a certain degree of flexibility. This allows it to withstand repeated folding, knotting, twisting, bending, and other complex deformations, making it more suitable for various electronic products.

[0057] In some embodiments of the present invention, applying an aqueous graphene oxide slurry to a substrate at least twice using a screen printing machine includes: determining the required number of coatings based on the desired thickness; adding the aqueous graphene oxide slurry to one end of the screen printing plate of the screen printing machine; applying pressure to the aqueous graphene oxide slurry with a squeegee to move it toward the other end of the screen printing plate, thus completing one coating on the substrate; and repeating the above process according to the required number of coatings. Furthermore, the squeegee angle is 40°-60°, the coating speed is 4-8 m / min, and the squeegee is a polyurethane flat-edged squeegee. The squeegee angle, speed, and flat-edged shape are all designed to ensure uniform slurry distribution during coating and to prevent slurry leakage from the screen onto the substrate.

[0058] In some embodiments of the present invention, the mesh size is 200-600 mesh. By selecting a screen printing plate with a suitable mesh size, the morphology and interlayer bubble structure of the graphene oxide film can be controlled, giving it good flexibility.

[0059] In some embodiments of the present invention, the screen printing plate is made of nylon. Nylon has a high melting point, does not change shape when heated, and has stable properties.

[0060] In some embodiments of the present invention, configuring the aqueous graphene oxide slurry according to requirements includes: selecting a corresponding type of graphene oxide according to requirements; adding the graphene oxide to deionized water to prepare an aqueous graphene oxide solution; and uniformly dispersing the graphene oxide in the deionized water by stirring and ultrasonication to obtain the aqueous graphene oxide slurry. Furthermore, the mass fraction of the aqueous graphene oxide solution is 1%-4%. An aqueous graphene oxide solution within this mass fraction range can ensure both the heat dissipation performance of the prepared functional graphene film and ensure smooth transfer from the screen to the substrate during the coating process.

[0061] In some embodiments of the present invention, the temperature range for thermal reduction is 100℃-1000℃, and the temperature range for graphitization is 2000℃-3000℃.

[0062] In some embodiments of the present invention, the substrate coated with graphene oxide aqueous slurry is heated by a hair dryer or an infrared lamp, and the heating temperature range is 30°C-90°C. The temperature range determines the film formation time and rate of the graphene oxide film.

[0063] In some embodiments of the present invention, the substrate is a PET substrate and the screen printing machine is a semi-automatic screen printing machine.

[0064] The following will illustrate the situation using comparative examples and different embodiments:

[0065] Example 1

[0066] like Figures 4 to 7 As shown, graphene oxide is selected according to the requirements, and graphene oxide is added to deionized water to prepare an aqueous solution with a mass fraction of 2%. The graphene oxide is uniformly dispersed in the deionized water by stirring and ultrasound to obtain an aqueous slurry of graphene oxide.

[0067] Determine the required number of coating passes based on the needs. Add the aqueous graphene oxide slurry to half of the screen printing plate on the screen printing machine. The screen printing plate is 200 mesh, the squeegee coating angle is 60°, and the coating speed is 4 m / min. The specific steps are as follows: Fix the PET substrate on the screen printing machine. Then, disperse a small amount of the aqueous graphene oxide slurry evenly on one end of the screen printing plate. Apply pressure to the slurry portion on the screen printing plate with the squeegee while moving it towards the other end of the screen to print the film. Simultaneously, use a hot air blower to assist in heating and drying the substrate coated with the aqueous graphene oxide slurry, allowing the slurry printed on the substrate to quickly set and form a film. The thickness of the graphene oxide film after a single screen printing and drying is 0.4 μm. By controlling the required number of coating passes, the thickness of the graphene oxide film can be achieved to 0.12 mm. Finally, peel the graphene oxide film off the PET substrate.

[0068] The stripped graphene oxide film was subjected to thermal reduction, graphitization, and calendering processes in sequence to obtain a functional graphene film.

[0069] The density of the above-mentioned functional graphene film, measured according to the hydrostatic weighing method in GB / T 4472-2011, is 1.26 g / cm³. 3 The thermal diffusivity was measured using a thermal diffusivity tester, and the result was 630m. 2 / S; The bending durability test was conducted using a durability testing machine. The test conditions were: the film was bent 180°, the number of bends was not less than 100,000, and the bending radius R = 1 mm. Then, the thermal diffusivity at the bend was measured using a thermal diffusivity tester. 2 / S.

[0070] Example 2

[0071] like Figure 8 and Figure 9 As shown, graphene oxide is selected according to the requirements, and graphene oxide is added to deionized water to prepare an aqueous solution with a mass fraction of 2%. The graphene oxide is uniformly dispersed in the deionized water by stirring and ultrasound to obtain an aqueous slurry of graphene oxide.

[0072] Determine the required number of coating passes based on the needs. Add the graphene oxide aqueous slurry to half of the screen printing plate on the screen printing machine. The screen printing plate is 600 mesh, the squeegee coating angle is 60°, and the coating speed is 6 m / min. The specific steps are as follows: Fix the PET substrate on the screen printing machine. Then, disperse a small amount of graphene oxide aqueous slurry evenly on one end of the screen printing plate. Apply pressure to the slurry portion on the screen printing plate with the squeegee while moving it towards the other end of the screen printing to print the film. Simultaneously, use a hot air blower to assist in heating and drying the substrate coated with graphene oxide aqueous slurry, allowing the slurry printed on the substrate to quickly set into a film. The thickness of the graphene oxide film after a single screen printing and drying is 0.3 μm. By controlling the required number of coating passes, the thickness of the graphene oxide film is made to 0.11 mm. Finally, peel the graphene oxide film off the PET substrate.

[0073] The stripped graphene oxide film was subjected to thermal reduction, graphitization, and calendering processes in sequence to obtain a functional graphene film.

[0074] The density of the above-mentioned functional graphene film, measured according to the hydrostatic weighing method in 4.2.3 of GB / T 4472-2011, is 1.30 g / cm³. 3 The thermal diffusivity was 595m using a thermal diffusivity tester. 2 / S; The bending durability test was conducted using a durability testing machine. The test conditions were: the film was bent 180°, the number of bends was not less than 100,000, and the bending radius R = 1 mm. Then, the thermal diffusivity at the bend was measured using a thermal diffusivity tester. The result was 563 m. 2 / S.

[0075] Example 3

[0076] like Figure 10 and Figure 11 As shown, graphene oxide is selected according to the requirements, and graphene oxide is added to deionized water to prepare an aqueous solution with a mass fraction of 4%. The graphene oxide is uniformly dispersed in the deionized water by stirring and ultrasound to obtain an aqueous slurry of graphene oxide.

[0077] Determine the required number of coating passes based on the needs. Add the aqueous graphene oxide slurry to half of the screen printing plate on the screen printing machine. The screen printing plate is 200 mesh, the squeegee coating angle is 60°, and the coating speed is 6 m / min. The specific steps are as follows: Fix the PET substrate on the screen printing machine. Then, disperse a small amount of the aqueous graphene oxide slurry evenly on one end of the screen printing plate. Apply pressure to the slurry portion on the screen printing plate with the squeegee while moving it towards the other end of the screen printing to print the film. Simultaneously, use an infrared lamp to assist in heating and drying the substrate coated with the aqueous graphene oxide slurry, allowing the slurry printed on the substrate to quickly set and form a film. The thickness of the graphene oxide film after a single screen printing and drying is 0.5 μm. By controlling the required number of coating passes, the thickness of the graphene oxide film can be achieved to 0.14 mm. Finally, peel the graphene oxide film off the PET substrate.

[0078] The stripped graphene oxide film was subjected to thermal reduction, graphitization, and calendering processes in sequence to obtain a functional graphene film.

[0079] The density of the above-mentioned functional graphene film, measured according to the hydrostatic weighing method in GB / T 4472-2011, is 1.28 g / cm³. 3 The thermal diffusivity was 623m using a thermal diffusivity tester. 2 / S; The bending durability test was conducted using a durability testing machine. The test conditions were: the film was bent 180°, the number of bends was not less than 100,000, and the bending radius R = 1 mm. Then, the thermal diffusivity at the bend was measured using a thermal diffusivity tester, and the result was 602 m. 2 / S.

[0080] Example 4

[0081] like Figure 12 and Figure 13 As shown, graphene oxide is selected according to the requirements, and graphene oxide is added to deionized water to prepare an aqueous solution with a mass fraction of 2%. The graphene oxide is uniformly dispersed in the deionized water by stirring and ultrasound to obtain an aqueous slurry of graphene oxide.

[0082] Determine the required number of coating passes based on the needs. Add the aqueous graphene oxide slurry to half of the screen printing plate on the screen printing machine. The screen printing plate is 200 mesh, the squeegee coating angle is 40°, and the coating speed is 8 m / min. The specific steps are as follows: Fix the PET substrate on the screen printing machine. Then, disperse a small amount of the aqueous graphene oxide slurry evenly on one end of the screen printing plate. Apply pressure to the slurry portion on the screen printing plate with the squeegee while moving it towards the other end of the screen printing to print the film. Simultaneously, use a hot air blower to assist in heating and drying the substrate coated with the aqueous graphene oxide slurry, allowing the slurry printed on the substrate to quickly set and form a film. The thickness of the graphene oxide film after a single screen printing and drying is 0.4 μm. By controlling the required number of coating passes, the thickness of the graphene oxide film can be achieved to 0.14 mm. Finally, peel the graphene oxide film off the PET substrate.

[0083] The stripped graphene oxide film was subjected to thermal reduction, graphitization, and calendering processes in sequence to obtain a functional graphene film.

[0084] The density of the above-mentioned functional graphene film, measured according to the hydrostatic weighing method in 4.2.3 of GB / T 4472-2011, is 1.30 g / cm³. 3 The thermal diffusivity was measured using a thermal diffusivity tester, and the result was 605 μm. 2 / S; The bending durability test was conducted using a durability testing machine. The test conditions were: the film was bent 180°, the number of bends was not less than 100,000, and the bending radius R = 1 mm. Then, the thermal diffusivity at the bend was measured using a thermal diffusivity tester. The result was 582 m. 2 / S.

[0085] As can be seen from Examples 1, 2, 3 and 4, it still has good heat dissipation performance after at least 100,000 bends, and the change in thermal diffusivity before and after bending is within 10%, which enables it to meet the requirements of high heat dissipation performance as well as the flexibility requirements of complex and ever-changing electronic devices for functional graphene films.

[0086] like Figure 2 As shown, the second aspect of the present invention provides a functional graphene film, which is obtained by the preparation method of the functional graphene film in any of the above technical solutions, comprising at least two graphene layers, and a bubble structure is provided between two adjacent graphene layers.

[0087] The functional graphene film of this invention has the same beneficial effects as the functional graphene film prepared by the preparation method of any of the above-mentioned technical solutions, and will not be repeated here.

[0088] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a functional graphene film, characterized in that, include: Configure graphene oxide aqueous slurry according to requirements; The aqueous graphene oxide slurry is applied to the substrate at least twice using a screen printing machine. The substrate coated with the aqueous slurry of graphene oxide is heated to obtain a graphene oxide film, and the graphene oxide film is peeled off from the substrate; during heating, a bubble structure is formed at the mesh position between the two layers of graphene oxide film. The graphene oxide film is subjected to thermal reduction, graphitization, and calendering to obtain a functional graphene film.

2. The method for preparing the functional graphene film according to claim 1, characterized in that, The process of applying the graphene oxide aqueous slurry to the substrate at least twice using a screen printing machine includes: Determine the required number of coating passes based on the desired thickness; The graphene oxide aqueous slurry is added to one end of the screen printing plate of the screen printing machine. Pressure is applied to the graphene oxide aqueous slurry by a squeegee to move it toward the other end of the screen printing plate, thus completing one coating on the substrate. The above process is repeated according to the required number of coatings.

3. The method for preparing the functional graphene film according to claim 2, characterized in that, The coating angle of the doctor blade is 40°-60°, and the coating speed is 4-8m / min.

4. The method for preparing the functional graphene film according to claim 2, characterized in that, The scraper is a polyurethane flat-edged scraper.

5. The method for preparing the functional graphene film according to claim 2, characterized in that, The screen printing plate has a mesh count of 200-600.

6. The method for preparing the functional graphene film according to claim 2, characterized in that, The screen printing plate is made of nylon.

7. The method for preparing the functional graphene film according to claim 1, characterized in that, The graphene oxide aqueous slurry configured according to requirements includes: Select the appropriate model of graphene oxide according to your needs; The graphene oxide was added to deionized water to prepare an aqueous solution of graphene oxide. The graphene oxide was uniformly dispersed in the deionized water by stirring and ultrasonication to obtain the graphene oxide aqueous slurry.

8. The method for preparing the functional graphene film according to claim 7, characterized in that, The mass fraction of the aqueous graphene oxide solution is 1%-4%.

9. The method for preparing the functional graphene film according to claim 1, characterized in that, The temperature range for thermal reduction is 100℃-1000℃, and the temperature range for graphitization is 2000℃-3000℃.

10. The method for preparing the functional graphene film according to claim 1, characterized in that, The substrate coated with the aqueous graphene oxide slurry is heated by a hair dryer or an infrared lamp, and the heating temperature range is 30℃-90℃.

11. A functional graphene film, obtained by the preparation method of the functional graphene film according to any one of claims 1-10, comprising at least two graphene layers, wherein a bubble structure is provided between adjacent graphene layers.

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