A graphene-polymer composite film prepared with sacrificial layer assistance and its preparation method

Abstract

This invention belongs to the field of composite material preparation technology, specifically relating to a graphene-polymer composite film prepared with the aid of a sacrificial layer and its preparation method, comprising the following steps: etching a graphene film / copper foil with a sacrificial layer in an ammonium sulfate solution to remove the copper foil, thereby obtaining a sacrificial layer / graphene film composite; wherein the sacrificial layer is in contact with the graphene film; the concentration of the ammonium sulfate solution is 1 mol / L to 5 mol / L; loading the sacrificial layer / graphene film composite onto a substrate on which a polymer layer has grown, and ensuring that the graphene film is in contact with the polymer layer; after annealing, immersing the substrate in an etching solution to remove the sacrificial layer, thereby obtaining the graphene-polymer composite film.

Description

Technical Field

[0001] This invention belongs to the field of composite material preparation technology, specifically relating to a graphene-polymer composite film prepared with the aid of a sacrificial layer and its preparation method. Background Technology

[0002] Graphene / polymer composites have become a research hotspot in materials science due to their excellent mechanical properties, such as ultra-high strength, significant reinforcement effect, outstanding electrical properties (high conductivity), and excellent thermal conductivity. Of particular note is that graphene's ultra-high intrinsic strength of 130 GPa and atomic-level thickness allow for significant improvements in the mechanical properties of the polymer matrix even with extremely low filler content, typically <1 wt%. Traditional methods for preparing these composites mainly rely on the physical blending of exfoliated graphene nanosheets with a polymer matrix. While the process is relatively simple, it faces two key technical challenges: first, randomly dispersed graphene nanosheets are difficult to form an effective continuous network, resulting in performance improvements far below theoretical expectations; second, graphene nanosheets are prone to aggregation due to strong π-π interactions, severely affecting the uniformity and performance stability of the composite material. In recent years, the preparation of large-area few-layer graphene films using chemical vapor deposition (CVD) has provided a new approach to overcoming this technological bottleneck. By directly growing continuous, uniform, high-quality graphene films on copper foil substrates and then performing interlayer composites with polymer films, layered nanocomposites with directional reinforcement effects can be constructed. This novel composite strategy not only effectively avoids the problem of uneven dispersion in traditional blending methods but also fully utilizes the excellent properties of graphene's in-plane anisotropy, opening up a new avenue for developing next-generation high-performance composite materials. However, some problems still exist in the method of preparing graphene-polymer composites using CVD. In existing related work, polymer nanofilms with a thickness of <100 nm are usually spin-coated directly onto copper foil on which graphene is grown to achieve the composite of polymer nanofilms and few-layer graphene. However, the composite films prepared by this method have problems such as uneven thickness and defects.

[0003] In the development of graphene application technologies, interface engineering has always been a key challenge for two core application scenarios. On the one hand, for semiconductor chip applications, it is necessary to achieve non-destructive and clean transfer of graphene to maintain its intrinsic electrical properties. On the other hand, in the fields of composite materials and flexible electronic devices, it is necessary to solve the problem of efficient composite of graphene and polymer matrices. Both types of applications essentially focus on the problem of graphene-polymer interface regulation. It is the physical / chemical interactions at the interface, including adhesion energy, stress transfer, and charge transfer, that directly determine the final performance of the material. Of particular concern is that interface defects generated during the transfer process, such as wrinkles, cracks, and interface contaminants, such as polymer residues, can significantly affect the performance of subsequent composite materials. This is the bottleneck of transfer technology that will be discussed in depth in the next section.

[0004] In traditional large-area graphene film transfer processes, researchers typically prepare polymer-graphene composites by spin-coating polymers directly onto the graphene / copper foil surface. However, this method has significant technical limitations in practical applications. First, there's the issue of substrate flatness. Commercial copper foil is prone to mechanical deformation during storage and transportation, such as wrinkles and depressions, resulting in insufficient surface flatness. When spin-coating ultrathin polymer films, especially those with a thickness <100 nm, the microscopic undulations of the substrate severely affect film uniformity, causing localized thickness differences and consequently impacting the performance stability of the composite material. Second, there's the issue of film defects. Due to the uneven deposition of polymers on non-ideal surfaces, the transferred composite film often exhibits numerous microscopic defects such as wrinkles, bubbles, and interface separation. These defects not only significantly reduce the mechanical strength of the composite material, such as tensile strength and toughness, but also disrupt the continuous conductive / thermal network of graphene, leading to degradation of electrical and thermal properties. Thirdly, there is the issue of interfacial bonding. Polymer-graphene interfaces formed by direct spin coating often exhibit weak adhesion, leading to low stress transfer efficiency and hindering the full utilization of graphene's mechanical reinforcing properties. Furthermore, residual solvents or incompletely cured polymers may further weaken the interfacial bonding strength, affecting the material's long-term stability. These limitations severely restrict the application of polymer-graphene composites in high-performance flexible electronics, thermally conductive interface materials, and other fields. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a graphene-polymer composite film prepared with the aid of a sacrificial layer and a preparation method thereof. This invention uses a sacrificial layer to support the graphene layer, ensuring its flatness. The polymer layer and graphene layer are placed on two separate substrates. The graphene layer is loaded onto the polymer layer using the sacrificial layer, and then the sacrificial layer is removed by etching, thereby achieving large-area transfer of the graphene layer. Furthermore, the transferred layer exhibits uniform thickness and significantly reduced surface roughness.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows.

[0007] A method for preparing a graphene-polymer composite film with sacrificial layer assistance includes the following steps:

[0008] A graphene film / copper foil with a sacrificial layer is etched in an ammonium sulfate solution to remove the copper foil, resulting in a sacrificial layer / graphene film composite; wherein the sacrificial layer is in contact with the graphene film.

[0009] The sacrificial layer / graphene film composite was loaded onto a substrate on which a polymer layer was grown, and the graphene film was brought into contact with the polymer layer. After annealing, it was placed in an etching solution for etching to remove the sacrificial layer and obtain a graphene-polymer composite film.

[0010] The sacrificial layer is obtained by spraying any one of ethyl cellulose solution, polyvinyl butyral solution, cyclododecane solution, camphor solution, cellulose acetate solution, and polyethylene glycol solution onto a graphene film / metal substrate.

[0011] This invention uses a sacrificial layer to support the graphene film and employs ammonium sulfate solution for etching, which removes the copper foil without damaging the sacrificial layer or the graphene film. The resulting sacrificial layer / graphene film composite is loaded onto a substrate with a polymer layer grown on its surface. The sacrificial layer is then etched away using an etching solution, thereby transferring the entire graphene film onto the polymer layer. The resulting graphene-polymer composite film has a smooth and uniform surface. By using any one of the following raw materials—ethyl cellulose solution, polyvinyl butyral solution, cyclododecane solution, camphor solution, cellulose acetate solution, and polyethylene glycol solution—as the raw material for preparing the sacrificial layer, a uniform film can be formed on the graphene film to support it. Simultaneously, it ensures that the graphene film is smoothly and uniformly loaded onto the polymer film. The resulting film exhibits a significantly reduced root mean square roughness (RMS), and the sacrificial layer does not damage the structure of the graphene film, thus ensuring its integrity and enabling the transfer of large-area graphene films.

[0012] In another preferred embodiment, the ethyl cellulose solution has a mass percentage of 0.5% to 8%; the polyvinyl butyral solution has a mass percentage of 0.5% to 6%; the cyclododecane solution has a mass percentage of 1% to 8%; the camphor solution has a mass percentage of 1% to 5%; the cellulose acetate solution has a mass percentage of 0.5% to 8%; and the polyethylene glycol solution has a mass percentage of 0.5% to 5%.

[0013] In another preferred embodiment, when the sacrificial layer is prepared from ethyl cellulose solution, polyvinyl butyral solution, and camphor solution, the etching solution is ethanol;

[0014] When the sacrificial layer is prepared from a cyclododecane solution, the etching solution is cyclohexane;

[0015] When the sacrificial layer is prepared from a cellulose acetate solution, the etching solution is acetone;

[0016] When the sacrificial layer is prepared from a polyethylene glycol solution, the etching solution is water. By setting corresponding etching solutions for different sacrificial layers, it can be ensured that the graphene film is not damaged while the sacrificial layer is etched away, thereby achieving the transfer of large-area graphene films.

[0017] In another preferred embodiment, the concentration of the ammonium sulfate solution is 1 mol / L to 5 mol / L.

[0018] In another preferred embodiment, the thickness of the graphene film is 0.34 nm to 10 nm, and the thickness of the polymer layer is 5 nm to 100 nm.

[0019] In another preferred embodiment, the polymer layer is any one of a polycarbonate layer, a polymethyl methacrylate layer, a polystyrene layer, and a polyvinyl alcohol layer.

[0020] In another preferred embodiment, the polymer layer is prepared by spin-coating any one of the following solutions by mass percentage—a polycarbonate solution, a polymethyl methacrylate solution, a polystyrene solution, or a polyvinyl alcohol solution—onto a substrate.

[0021] In another preferred embodiment, the solvent in the polycarbonate solution, the polymethyl methacrylate solution, the polystyrene solution, and the polyvinyl alcohol solution is tetrachloroethane.

[0022] In another preferred embodiment, the substrate is a silicon wafer. Compared to copper foil, silicon wafers are harder and less prone to deformation, thus ensuring the flatness and uniformity of the polymer layer. The annealing treatment is performed at a temperature of 80°C to 100°C for 30 minutes to 8 hours.

[0023] The second aspect of the present invention provides a method for preparing a graphene-polymer composite film using the aforementioned sacrificial layer-assisted preparation method.

[0024] Compared with the prior art, the present invention has the following beneficial effects.

[0025] This invention utilizes a sacrificial layer to support a graphene film, ensuring its flatness. The polymer layer and graphene layer are placed on two different substrates. The graphene layer is loaded onto the polymer layer via the sacrificial layer, which is then removed by etching, achieving large-area transfer of the graphene layer with uniform thickness. The invention selects ethyl cellulose, camphor, cyclododecane, polyvinyl butyral, cellulose acetate, and polyethylene glycol as sacrificial layer materials. These materials form a uniform and continuous film, providing a flat supporting surface for the graphene. Furthermore, the sacrificial layer exhibits a certain degree of adhesion to the graphene film while maintaining a weak interaction force, effectively supporting the graphene layer without damaging it during sacrificial layer removal due to excessive adhesion. The use of ammonium sulfate solution ensures that the metal substrate is etched away without etching the sacrificial layer, allowing it to better support the graphene film.

[0026] This invention achieves the goal of large-area graphene layer transfer by using different etching solutions for different sacrificial layers. Attached Figure Description

[0027] Figure 1 The images show the three-dimensional image of the graphene-polymer composite film scanned by atomic force microscopy and the Raman spectroscopy characterization results of the surface in Example 1 of the present invention; wherein, A is the three-dimensional image of the surface scanned by atomic force microscopy and B is the Raman spectroscopy characterization result.

[0028] Figure 2 This is a three-dimensional image of the surface of the graphene-polymer composite film of Example 2 of the present invention obtained by atomic force microscopy.

[0029] Figure 3 This is a three-dimensional image of the surface of the graphene-polymer composite film of Example 3 of the present invention obtained by atomic force microscopy.

[0030] Figure 4 This is a three-dimensional image of the surface of the graphene-polymer composite film of Example 4 of the present invention obtained by atomic force microscopy.

[0031] Figure 5 Atomic force microscopy scanning three-dimensional image of the surface of the graphene-polymer composite film of Example 5 of the present invention.

[0032] Figure 6 Atomic force microscopy scanning three-dimensional image of the surface of the graphene-polymer composite film of Example 6 of the present invention.

[0033] Figure 7 This is a three-dimensional image of the surface of the graphene-polymer composite film in Comparative Example 1 obtained by atomic force microscopy scanning. Detailed Implementation

[0034] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0035] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0036] Solvents include deionized water, cyclohexane, acetone, ethanol, ethyl acetate, and tetrachloroethane; pharmaceuticals include ammonium persulfate (NH4)2S2O8, ethyl cellulose, camphor, cyclododecane, polyvinyl butyral, cellulose acetate, and polyethylene glycol. The sources of these raw materials are shown in Table 1.

[0037] Table 1 Sources of Raw Materials

[0038]

[0039] Abbreviations in Chinese and English: Ethyl cellulose is abbreviated as EC, and polycarbonate is abbreviated as PC.

[0040] The following is a detailed description of a method for preparing graphene-polymer composite films with the assistance of a sacrificial layer.

[0041] Example 1: A method for preparing graphene-polymer composite films with the assistance of a sacrificial layer, comprising the following steps.

[0042] S1. Polycarbonate is dissolved in tetrachloroethane to prepare a polycarbonate solution with a mass percentage of 0.6%; the silicon wafer is plasma cleaned to obtain a pretreated silicon wafer; the polycarbonate solution is spin-coated onto the pretreated silicon wafer at a speed of 5000 rpm to obtain a polycarbonate film with a thickness of 15 nm; the film is annealed at 100 °C for 30 min to remove the residual solvent in the polycarbonate film, and a substrate with a polycarbonate layer grown on its surface is obtained.

[0043] S2. Dissolve ethyl cellulose in deionized water to prepare an ethyl cellulose solution with a mass percentage of 2%; pour the ethyl cellulose solution into a spray bottle and spray it onto the graphene film / copper foil. After the solvent evaporates naturally, a sacrificial layer is formed on the graphene film, resulting in a graphene film / copper foil with a sacrificial layer; wherein, the thickness of the graphene film is 0.34 nm.

[0044] S3. Place the graphene film / copper foil with the sacrificial layer in a 1 mol / L ammonium sulfate solution for 2 hours to etch away the copper foil. After etching, wash with deionized water to obtain the sacrificial layer / graphene film composite.

[0045] S4. Using a substrate with a polycarbonate layer grown on its surface, the sacrificial layer / graphene film composite is retrieved from the ammonium sulfate solution, and the sacrificial layer / graphene film composite is loaded onto the polycarbonate layer, with the graphene film in contact with the polycarbonate layer. The film is rotated at 5000 rpm for 1 minute to remove moisture. The sacrificial layer is then etched with ethanol to remove it, resulting in a graphene-polycarbonate layered composite film.

[0046] Example 2: A method for preparing graphene-polymer composite films with the assistance of a sacrificial layer, comprising the following steps.

[0047] S1. Polycarbonate is dissolved in tetrachloroethane to prepare a polycarbonate solution with a mass percentage of 1%; silicon wafers are plasma cleaned to obtain pretreated silicon wafers; the polycarbonate solution is spin-coated onto the pretreated silicon wafers to obtain a polycarbonate film with a thickness of 50 nm; the film is annealed at 100 °C for 30 min to remove residual solvent in the polycarbonate film, resulting in a substrate with a polycarbonate layer grown on its surface.

[0048] S2. Dissolve ethyl cellulose in deionized water to prepare an ethyl cellulose solution with a mass percentage of 2%; pour the ethyl cellulose solution into a spray bottle and spray it onto the graphene film / copper foil. After the solvent evaporates naturally, a sacrificial layer is formed on the graphene film, resulting in a graphene film / copper foil substrate with a sacrificial layer. The thickness of the graphene film is 3 nm.

[0049] S3. Place the graphene film / copper foil substrate with the sacrificial layer in a 1 mol / L ammonium sulfate solution for 2 hours to etch away the copper foil. After etching, clean with deionized water to obtain the sacrificial layer / graphene film composite.

[0050] S4. Using a substrate with a polycarbonate layer grown on its surface, the sacrificial layer / graphene film composite is retrieved from the ammonium sulfate solution, and the sacrificial layer / graphene film composite is loaded onto the polycarbonate layer, with the graphene film in contact with the polycarbonate layer. The film is rotated at 5000 rpm for 1 minute to remove moisture. The sacrificial layer is then etched with ethanol to remove it, resulting in a graphene-polycarbonate layered composite film.

[0051] Example 3: A method for preparing graphene-polymer composite films with the assistance of a sacrificial layer, comprising the following steps.

[0052] S1. Polycarbonate is dissolved in tetrachloroethane to prepare a polycarbonate solution with a mass percentage of 2%; silicon wafers are plasma cleaned to obtain pretreated silicon wafers; the polycarbonate solution is spin-coated onto the pretreated silicon wafers to obtain a polycarbonate film with a thickness of 90 nm; the film is annealed at 100 °C for 30 min to remove residual solvent in the polycarbonate film, resulting in a substrate with a polycarbonate layer grown on its surface.

[0053] S2. Dissolve camphor in deionized water to prepare a camphor solution with a mass percentage of 2%; pour the camphor solution into a spray bottle and spray it onto the graphene film / copper foil. After the solvent evaporates naturally, a sacrificial layer is formed on the graphene film, resulting in a graphene film / copper foil substrate with a sacrificial layer.

[0054] S3. Place the graphene film / copper foil substrate with the sacrificial layer in a 1 mol / L ammonium sulfate solution for 2 hours to etch away the copper foil. After etching, clean with deionized water to obtain the sacrificial layer / graphene film composite.

[0055] S4. The sacrificial layer / graphene film composite is lifted from a substrate with a polycarbonate layer grown on its surface, and the sacrificial layer / graphene film composite is loaded onto the polycarbonate layer, with the graphene film in contact with the polycarbonate layer. It is rotated at 5000 rpm for 1 minute to remove moisture. The sacrificial layer is then etched with ethanol to remove it, resulting in a graphene-polycarbonate layered composite film.

[0056] Example 4: A method for preparing graphene-polymer composite films with the assistance of a sacrificial layer, comprising the following steps.

[0057] S1. Polymethyl methacrylate (PMMA) is dissolved in tetrachloroethane to prepare a PMMA solution with a mass percentage of 1%. The silicon wafer is plasma cleaned to obtain a pretreated silicon wafer. The PMMA solution is spin-coated onto the pretreated silicon wafer to obtain a PMMA film with a thickness of 50 nm. The film is annealed at 100 °C for 30 min to remove the residual solvent in the PMMA film, resulting in a substrate with a PMMA layer grown on its surface.

[0058] S2. Dissolve cellulose acetate in deionized water to prepare a 2% (w / w) cellulose acetate solution; pour the cellulose acetate solution into a spray bottle and spray it onto the graphene film / copper foil. After the solvent evaporates naturally, a sacrificial layer is formed on the graphene film, resulting in a graphene film / copper foil substrate with a sacrificial layer.

[0059] S3. Place the graphene film / copper foil substrate with the sacrificial layer in a 1 mol / L ammonium sulfate solution for 2 hours to etch away the copper foil. After etching, clean with deionized water to obtain the sacrificial layer / graphene film composite.

[0060] S4. Using a substrate with a polymethyl methacrylate (PMMA) layer grown on its surface, the sacrificial layer / graphene film composite is retrieved from the ammonium sulfate solution, and the sacrificial layer / graphene film composite is loaded onto the PMMA layer, with the graphene film in contact with the PMMA layer. The film is rotated at 5000 rpm for 1 minute to remove moisture. The sacrificial layer is then etched with acetone to remove it, yielding a graphene-PMMA layered composite film.

[0061] Example 5: A method for preparing graphene-polymer composite films with the assistance of a sacrificial layer, comprising the following steps.

[0062] S1. Polystyrene is dissolved in tetrachloroethane to prepare a 1% polystyrene solution by mass. The silicon wafer is plasma cleaned to obtain a pretreated silicon wafer. The polystyrene solution is spin-coated onto the pretreated silicon wafer to obtain a polystyrene film with a thickness of 50 nm. The film is annealed at 80 °C for 30 min to remove the residual solvent in the polystyrene film, resulting in a substrate with a polystyrene layer grown on its surface.

[0063] S2. Dissolve polyethylene glycol in deionized water to prepare a 2% polyethylene glycol solution by mass. Pour the polyethylene glycol solution into a spray bottle and spray it onto the graphene film / copper foil. Allow the solvent to evaporate naturally to form a sacrificial layer on the graphene film, thus obtaining a graphene film / copper foil substrate with a sacrificial layer.

[0064] S3. Place the graphene film / copper foil substrate with the sacrificial layer in a 1 mol / L ammonium sulfate solution for 2 hours to etch away the sacrificial layer. After etching, wash with deionized water to obtain the sacrificial layer / graphene film composite.

[0065] S4. Using a substrate with a polystyrene layer grown on its surface, the sacrificial layer / graphene film composite is retrieved from the ammonium sulfate solution, and the sacrificial layer / graphene film composite is loaded onto the polystyrene layer, with the graphene film in contact with the polystyrene layer. The film is rotated at 5000 rpm for 1 minute to remove moisture. The sacrificial layer is then etched with water to remove it, resulting in a graphene-polystyrene layered composite film.

[0066] Example 6: A method for preparing graphene-polymer composite films with the assistance of a sacrificial layer, comprising the following steps.

[0067] S1. Polyvinyl alcohol is dissolved in tetrachloroethane to prepare a 1% polyvinyl alcohol solution by mass. The silicon wafer is plasma cleaned to obtain a pretreated silicon wafer. The polyvinyl alcohol solution is spin-coated onto the pretreated silicon wafer to obtain a polyvinyl alcohol film with a thickness of 50 nm. The film is annealed at 80 °C for 30 min to remove the residual solvent in the polyvinyl alcohol film, resulting in a substrate with a polyvinyl alcohol layer grown on its surface.

[0068] S2. Dissolve ethyl cellulose in deionized water to prepare an ethyl cellulose solution with a mass percentage of 2%; pour the ethyl cellulose solution into a spray bottle and spray it onto the graphene film / copper foil. After the solvent evaporates naturally, a sacrificial layer is formed on the graphene film, resulting in a graphene film / copper foil substrate with a sacrificial layer.

[0069] S3. Place the graphene film / copper foil substrate with the sacrificial layer in a 1 mol / L ammonium sulfate solution for 2 hours to etch away the copper foil. After etching, clean with deionized water to obtain the sacrificial layer / graphene film composite.

[0070] S4. Using a substrate with a polyvinyl alcohol layer grown on its surface, the sacrificial layer / graphene film composite is retrieved from the ammonium sulfate solution, and the sacrificial layer / graphene film composite is loaded onto the polyvinyl alcohol layer, with the graphene film in contact with the polyvinyl alcohol layer. The film is rotated at 5000 rpm for 1 minute to remove moisture. The sacrificial layer is then etched with ethanol to remove it, resulting in a graphene-polyvinyl alcohol layered composite film.

[0071] Comparative Example 1

[0072] Except for spin-coating the polycarbonate solution directly onto the graphene film / copper foil and then etching away the copper to obtain the composite film, the other steps are the same as in Example 1.

[0073] Atomic force microscopy was performed on the composite films prepared in Examples 1-6 and Comparative Example 1, and the results are as follows: Figures 1-7 As shown. Figures 1-6 These are the result figures from Embodiments 1 to 6 of the present invention. Figure 7 The image shown is from Comparative Example 1. It can be seen that the three-dimensional surface image of the composite film obtained by spin-coating directly onto copper foil using atomic force microscopy exhibits significant height variation (RMS 218.86 nm). Furthermore, based on Raman spectroscopy results, a virtually defect-free composite film was obtained, with a root square roughness (RMS) between 0.63 nm and 4.9 nm. In contrast, the film obtained using the sacrificial layer-assisted transfer method of this invention has a smoother surface and more uniform thickness.

[0074] Based on this, more perfect composite film samples can be prepared in a wide range of scientific research; and methods are provided for preparing devices with better performance.

[0075] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for fabricating a graphene-polymer composite film by a sacrificial layer-assisted fabrication, characterized in that, The method comprises the following steps: etching the graphene film / copper foil with a sacrifice layer in an ammonium sulfate solution to remove the copper foil and obtain a sacrifice layer / graphene film composite, wherein the sacrifice layer is in contact with the graphene film; loading the sacrifice layer / graphene film composite on a substrate with a polymer layer grown on the surface, and making the graphene film contact with the polymer layer, annealing, and then etching in an etching solution to remove the sacrifice layer and obtain a graphene-polymer composite film, wherein the annealing temperature is 80-100 DEG C; the sacrifice layer is prepared by spraying any one of an ethyl cellulose solution, a polyvinyl butyral solution, a cyclododecane solution, a camphor solution, a cellulose acetate solution, and a polyethylene glycol solution on the graphene film / copper foil; when the sacrifice layer is prepared by the ethyl cellulose solution, the polyvinyl butyral solution, or the camphor solution, the etching solution is ethanol; when the sacrifice layer is prepared by the cyclododecane solution, the etching solution is cyclohexane; when the sacrifice layer is prepared by the cellulose acetate solution, the etching solution is acetone; when the sacrifice layer is prepared by the polyethylene glycol solution, the etching solution is water; the thickness of the graphene film is 0.34-10 nm, and the thickness of the polymer layer is 5-100 nm; the polymer layer is any one of a polycarbonate layer, a polymethyl methacrylate layer, a polystyrene layer, and a polyvinyl alcohol layer.

2. The method according to claim 1, wherein the mass percentage of the ethyl cellulose solution is 0.5-8%; the mass percentage of the polyvinyl butyral solution is 0.5-6%; the mass percentage of the cyclododecane solution is 1-8%; the mass percentage of the camphor solution is 1-5%; the mass percentage of the cellulose acetate solution is 0.5-8%; the mass percentage of the polyethylene glycol solution is 0.5-5%. the concentration of the ammonium sulfate solution is 1-5 mol / L.

3. The method of claim 1, wherein the graphene-polymer composite film is prepared by a sacrificial layer assisted process. the polymer layer is prepared by spin coating any one of a polycarbonate solution with a mass percentage of 0.6-2%, a polymethyl methacrylate solution with a mass percentage of 0.6-2%, a polystyrene solution with a mass percentage of 0.6-2%, and a polyvinyl alcohol solution with a mass percentage of 0.6-2% on the substrate.

4. The method of claim 3, wherein the graphene-polymer composite film is prepared by a sacrificial layer-assisted process. the solvents of the polycarbonate solution, the polymethyl methacrylate solution, and the polystyrene solution are all tetrachloroethane.

5. The method of claim 4, wherein the graphene-polymer composite film is prepared by a sacrificial layer-assisted process, and the sacrificial layer is removed by a solvent. the substrate is a silicon wafer, and the annealing time is 30 min-8 h.

6. The method of claim 5, wherein the graphene-polymer composite film is prepared by a sacrificial layer assisted process.

7. A graphene-polymer composite film prepared by the method according to any one of claims 1-6. ​

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