Graphene film material reinforced by mechanical interlocking for toughening and its preparation and application

Abstract

The application provides a graphene film material with mechanical bond reinforced toughening and a preparation and application thereof; the preparation method comprises the following steps: synthesizing a bifunctional mechanical interlocking molecule, dissolving the mechanical interlocking molecule in an organic solvent, and using the mechanical interlocking molecule to soak an oxidized graphene film; according to the type of the functional groups carried by the mechanical interlocking molecule, an agent that is helpful for the combination of the mechanical interlocking molecule and the oxidized graphene is added into the organic solvent; the graphene film material obtained after soaking is subjected to washing and drying treatment; the graphene film material is soaked in hydriodic acid, and then subjected to washing and drying treatment, so that the graphene film material with mechanical bond reinforced toughening is obtained; the mechanical interlocking molecule in the graphene film material with mechanical bond reinforced toughening is one of a rotaxane, a catenane and a daisy chain. The graphene film material is bridged by mechanical bonds through the method, so that the graphene film material is reinforced and toughened.

Description

Technical Field

[0001] This invention belongs to the field of synthetic chemistry and nanocomposite material preparation, and relates to a method for preparing graphene film materials that are reinforced and toughened by mechanical bonds. Specifically, it relates to a method for preparing reinforced and toughened graphene film materials using mechanically interlocked molecules. Background Technology

[0002] Graphene, due to its excellent mechanical strength and conductivity, holds immense promise for applications in numerous fields, including supercapacitors, flexible electronic devices, electromagnetic interference shielding materials, and aerospace. However, once macroscopic thin films are formed, the weak interlayer interactions (primarily hydrogen bonds) often cause the loss of its superior performance, limiting further application development. Therefore, obtaining high-performance graphene thin film materials presents a significant challenge. The surface of graphene materials typically contains abundant oxygen-containing functional groups, which facilitates the formation of covalent / non-covalent bonds between layers, thereby modulating the interactions between them. Current research focuses primarily on enhancing the strength of graphene thin film materials by introducing covalent / non-covalent bonds, but improvements in elongation have been limited.

[0003] Mechanical bonds are spatial network entanglements, primarily found in mechanically interlocked molecules, which are a class of molecules with unique topological structures formed based on host-guest recognition. Compared to traditional covalent / non-covalent bonds, mechanical bonds enable controllable intramolecular motion. Simultaneously, mechanical bonds possess both dynamism and stability; under the influence of forces, they can undergo intramolecular motion and dissipate energy, yet their structure remains stable. However, research utilizing mechanical bonds to enhance and toughen graphene thin film materials is rarely reported. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a two-dimensional thin film material reinforced and toughened by mechanical bonds, its preparation method, and its applications. The graphene thin film material prepared by bridging graphene material sheets with mechanical bonds exhibits excellent mechanical properties, stretchability, conductivity, and multifunctionality. The preparation method is simple and universally applicable.

[0005] The objective of this invention is achieved through the following solution: In a first aspect, the present invention provides a method for preparing a graphene thin film material reinforced and toughened by mechanical bonds, the method comprising the following steps: S1. Synthesize a bifunctional mechanically interlocked molecule; wherein the bifunctional mechanically interlocked molecule contains two functional groups; S2. Dissolve the mechanically interlocked molecules obtained in step S1 in an organic solvent and soak the graphene oxide film; the main reaction between the functional groups of the mechanically interlocked molecules and the oxygen-containing functional groups on the surface of graphene oxide is the formation of covalent bonds. S3. The graphene oxide film material obtained in step S2 is washed and dried. S4. The graphene oxide film obtained in step S3 is soaked in hydroiodic acid, and then washed and dried to obtain a mechanically reinforced and toughened graphene film material.

[0006] In one embodiment of the present invention, in step S1, the mechanically interlocking molecule is at least one of rotaxane, sesquicarbon, and daisy chain.

[0007] As one embodiment of the present invention, in step S1, the two functional groups are the same or different; the functional group is selected from one of hydroxyl, carboxyl, and epoxy groups.

[0008] In one embodiment of the present invention, hydrogen bonds may also be generated in step S2, but since their strength is much smaller than that of covalent bonds, they can be disregarded.

[0009] In one embodiment of the present invention, in step S2, the covalent bond reaction includes esterification and / or epoxy ring-opening reaction. Examples include esterification between a hydroxyl group and a carboxyl group; and epoxy ring-opening reaction between an epoxy group and a carboxyl group. Epoxy ring-opening reaction between an epoxy group and a carboxyl group can occur at high temperatures, such as 80-90°C.

[0010] In one embodiment of the present invention, when the functional group carried by the mechanically interlocking molecule is a hydroxyl group, the covalent bond reaction is an esterification reaction, and a reagent that facilitates the binding of the mechanically interlocking molecule and graphene oxide is added to the organic solvent in step S2. The reagent includes at least one of a catalyst and a coupling agent.

[0011] In one embodiment of the present invention, the coupling agent is selected from one of dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. The amount of coupling agent added to the organic solvent ranges from 2 to 4 times the molar equivalent of the added mechanical interlocking molecules. In some embodiments, the amount of coupling agent added ranges from 2.4 times the molar equivalent of the added mechanical interlocking molecules.

[0012] In one embodiment of the present invention, the catalyst is selected from 4-dimethylaminopyridine, 1,8-diazabicyclo[5.4.0]undec-7-ene, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene. The amount of catalyst added to the organic solvent is 0.1-0.5 times the molar equivalent of the added mechanical interlocking molecules. In some embodiments, the amount of catalyst added is 0.2 times the molar equivalent of the added mechanical interlocking molecules.

[0013] In one embodiment of the present invention, the esterification reaction is carried out at 20-40°C for 1-6 hours. In some embodiments, the esterification reaction is carried out at room temperature for 3 hours.

[0014] In one embodiment of the present invention, when the covalent bond reaction is an epoxy ring-opening reaction, the participation of a catalyst and coupling agent is not required. This is exemplified by cases where the functional group carried by the mechanically interlocked molecule is an epoxy group. The reaction temperature for the epoxy ring-opening reaction is 80-100 °C, and the reaction time is 8-24 hours. In some embodiments, the reaction temperature for the epoxy ring-opening reaction is 80 °C, and the reaction time is 12 hours.

[0015] In one embodiment of the present invention, in step S2, the surface of the graphene oxide film has oxygen-containing functional groups. These oxygen-containing functional groups include one or more of hydroxyl, carboxyl, and epoxy groups.

[0016] In one embodiment of the present invention, in step S2, the graphene oxide film is a self-supporting membrane prepared by vacuum filtration of an aqueous solution of graphene oxide.

[0017] In one embodiment of the present invention, in step S2, the organic solvent is selected from at least one of tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, dichloromethane, trichloromethane, and dimethyl sulfoxide.

[0018] In one embodiment of the present invention, in step S2, the mechanically interlocking molecules are dissolved in a mixed solution formed by an organic solvent, and the content of the mechanically interlocking molecules ranges from 3 to 10 mg / mL.

[0019] In one embodiment of the present invention, in step S2, the thickness of the graphene oxide film is controlled to be 3-10 mm. µ m.

[0020] In one embodiment of the present invention, in step S2, the soaking process is carried out at 20-40°C for 2-12 hours. The esterification reaction, with the participation of a catalyst, is highly efficient, occurs at room temperature, and is completed within a few hours. In some embodiments, the soaking process is carried out at room temperature for 3 hours.

[0021] In one embodiment of the present invention, in step S3, the detergent used is ethanol, and the drying conditions are vacuum drying at 40-60 °C for 2-12 hours.

[0022] In one embodiment of the present invention, in step S4, the soaking process is carried out at 20-40°C for 2-6 hours. This soaking process involves the reduction of graphene oxide by hydroiodic acid, removing unreacted oxygen-containing functional groups from the surface of the graphene oxide and converting it into graphene. In some embodiments, the soaking process is carried out at room temperature for 3 hours.

[0023] In one embodiment of the present invention, in step S4, the detergent used is ethanol, and the drying conditions are vacuum drying at 40-60 °C for 2-12 hours.

[0024] A second aspect of the present invention provides a graphene film material reinforced and toughened by mechanical bonds, prepared using the preparation method described above.

[0025] A third aspect of the invention provides an application of a mechanically bond-reinforced graphene film material, wherein the mechanically bond-reinforced graphene film material is applied to a flexible electronic device, including a flexible electrode.

[0026] Compared with the prior art, the present invention has the following beneficial effects: 1. The method of the present invention bridges graphene film materials with mechanical bonds, and utilizes the intramolecular motion of mechanical bonds to enhance and toughen the graphene film materials. While improving strength and toughness, the elongation is also significantly improved.

[0027] 2. The method of this invention bridges graphene film materials with mechanical bonds, exhibiting excellent flexibility and stretchability. While maintaining a long stretching ratio, it can still conduct electricity, which is of great significance for the application development of graphene film materials. Attached Figure Description

[0028] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 These are the structural formulas of the relevant mechanically interlocking molecules listed in the embodiments of this invention; Figure 2 These are macroscopic photographs of the graphene film material prepared in Example 1 of this invention; Figure 3 These are scanning electron microscope images of the graphene thin film material prepared in Example 1 of this invention; Figure 4 This is the tensile stress-strain curve of the graphene film material prepared in Example 1 of this invention; Figure 5 This is a schematic diagram of the fatigue bending resistance of the graphene film material prepared in Example 1 of the present invention and a comparison diagram of the tensile mechanical properties before and after bending; Figure 6This is an image of the graphene film material prepared in Example 1 of the present invention used as a flexible electrode to drive a light-emitting diode; Figure 7 This is an image of the graphene film material prepared in Example 1 of the present invention used as a flexible electrode to drive a mechanical joint; Figure 8 The image shows the graphene film material prepared in Example 1 of this invention being used as a flexible electrode to drive a mechanical joint to grasp a small ball. Figure 9 This is the tensile stress-strain curve of the graphene film material prepared in Example 2 of this invention; Figure 10 This is a photograph of the graphene film material prepared in Example 3 of this invention folded into a windmill shape; Figure 11 This is the tensile stress-strain curve of the graphene film material prepared in Example 4 of this invention; Figure 12 This is the synthetic route for hydroxyl-containing [2]rotaxane in Example 1 of this invention; Figure 13 This is the 1H NMR spectrum of hydroxyl-containing [2]rotaxane in Example 1 of this invention; Figure 14 This is the high-resolution mass spectrum of hydroxyl-containing [2]rotaxane in Example 1 of this invention; Figure 15 This is the synthetic route for [2] rotaxane containing epoxy groups in Example 2 of this invention; Figure 16 This is the 1H NMR spectrum of [2]rotaxane containing an epoxy group in Example 2 of this invention; Figure 17 This is the high-resolution mass spectrum of [2] rotaxane containing an epoxy group in Example 2 of this invention; Figure 18 This is the synthetic route for the hydroxyl-containing daisy chain monomer in Example 4 of the present invention; Figure 19 This is the 1H NMR spectrum of the hydroxyl-containing daisy chain monomer in Example 4 of the present invention; Figure 20 This is a high-resolution mass spectrum of the hydroxyl-containing daisy chain monomer in Example 4 of the present invention. Detailed Implementation

[0029] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0030] The present invention will now be described in further detail with reference to specific embodiments.

[0031] The performance characteristics of the mechanically reinforced and toughened graphene film material obtained by this invention are as follows: The microstructure of the graphene film was obtained by field emission scanning electron microscopy (test voltage: 10 kV).

[0032] The stress-strain curves of the graphene film were obtained by a mechanical stretching machine (stretching rate of 0.2 mm / min).

[0033] Example 1 This embodiment provides a method for preparing a graphene thin film material reinforced and toughened using mechanical bonds. Specifically, it includes the following steps: Step 1: Design and synthesize hydroxyl-containing [2] rotaxanes, such as Figure 1 As shown in a, the synthesis steps are as follows: Figure 12 (The final product can be obtained by proportionally increasing or decreasing the amounts of reactants according to the synthetic route.) The proton NMR spectrum is shown below. Figure 13 , 1 H NMR (CDCl3, 298 K, 400 MHz) δ (ppm): 7.67 (s, 1H), 7.62 (dd, J = 8.5, 1.9 Hz, 1H), 7.46 (d, J = 1.9 Hz, 1H), 6.98 (s, 2H), 6.86 (d, J = 8.6 Hz, 1H), 6.61 (s, 3H), 5.16 (s, 2H), 4.36 (t, J = 7.2 Hz, 4H), 4.26 (t, J = 6.7 Hz, 2H), 4.22-4.12 (m,4H), 3.96-3.86 (m, 4H), 3.66-3.37 (m, 26H), 3.18-3.10 (m, 2H), 2.28 (s, 6H), 2.17 (d, J = 3.5 Hz, 6H), 1.90 (t, J = 6.9 Hz, 2H), 1.80–1.71 (m, 4H), 1.55–1.52 (m, 4H), 1.92–1.20 (m, 40H). Mass spectra are shown in [reference needed]. Figure 14 HRMS: m / z calcd for C 71 H 117 N4O 14,1249.8561 [M – PF6] + ; found 1249.8556 [M – PF6] + . Step 2: Dissolve the [2] rotaxane obtained in step 1 in tetrahydrofuran at a concentration of 5 mg / mL, take 5 mL to soak the graphene oxide film, and soak it in an environment of 25 °C for 3 hours.

[0034] Step 3: Add 10 mg of 4-dimethylaminopyridine and 10 mg of dicyclohexylcarbodiimide to the tetrahydrofuran soaked in the graphene oxide film in step 2, and continue to maintain the mixture at 25°C for 3 hours.

[0035] Step 4: Wash the graphene oxide film obtained in step 3 with anhydrous ethanol to remove unreacted [2] rotaxane, 4-dimethylaminopyridine and dicyclohexylcarbodiimide, and then place the washed graphene oxide film in a vacuum oven at 45 °C for 4 hours to dry.

[0036] Step 5: Soak the graphene oxide film obtained in step 4 in hydroiodic acid. After 3 hours, wash with anhydrous ethanol to remove the hydroiodic acid. Then, place the washed graphene film in a vacuum oven at 45 °C and dry for 4 hours.

[0037] Step 6: Set up a comparative experiment, replace the hydroxyl-containing [2] rotaxane with heptaethylene alcohol, and keep other conditions unchanged to obtain a heptaethylene alcohol-bridged graphene film; without adding [2] rotaxane and heptaethylene alcohol, a pure graphene film is obtained.

[0038] The performance of the three graphene films prepared in Example 1 was characterized and compared. For ease of description, RBG is used to represent the graphene film bridged with rotaxane [2], HBG is used to represent the graphene film bridged with heptaethylene glycol, and rGO is used to represent the pure graphene film; (1) RBG film can be bent without damage, such as Figure 2 As shown, this indicates that the film is flexible. (2) The cross-section of the RBG film is stacked in layers, and the nitrogen element is uniformly dispersed, as shown in the figure. Figure 3 As shown, [2] rotaxane is uniformly dispersed in the graphene film. (3) The mechanical properties of RBG film are better than those of HBG and rGO film, such as Figure 4 As shown, the presence of [2] rotaxane improves the performance of graphene films, thus further demonstrating that mechanical bonds can be used to prepare reinforced and toughened graphene film materials. (4) After 100 repeated 180° bending, the mechanical properties of RBG films can still be maintained at a high level, such as Figure 5 As shown, this demonstrates that the RBG film exhibits good resistance to fatigue bending.

[0039] The RBG thin film prepared in Example 1 was subjected to application experiments, such as... Figure 6 As shown, when the film is stretched to 20% elongation, the brightness of the LED remains essentially unchanged. However, when the elongation reaches 23%, the film breaks, and the LED turns off. When the film is adhered to a finger and bent, the brightness of the LED remains unaffected, demonstrating the excellent stretchability and flexibility of the RBG film. Furthermore, the RBG film, as a flexible electrode, can drive the movement of mechanical joints and can grasp small balls, such as… Figure 7 and Figure 8 As shown. In summary, the obtained mechanically bonded graphene film material possesses excellent mechanical properties and fatigue resistance, as well as excellent flexibility and stretchability, making it suitable for use as a flexible electrode with broad application prospects.

[0040] Example 2 This embodiment provides a method for preparing a graphene thin film material reinforced and toughened using mechanical bonds. Specifically, it includes the following steps: Step 1: Design and synthesize rotaxanes containing epoxy groups [2], such as Figure 1 As shown in b, the synthesis steps are as follows: Figure 15 (The final product can be obtained by proportionally increasing or decreasing the amounts of reactants according to the synthetic route.) The proton NMR spectrum is shown below. Figure 16 , 1 HNMR (CDCl3, 298 K, 400 MHz) δ (ppm): 7.64 (d, J = 7.5 Hz, 1H), 7.48 (s, 1H), 7.46(d, J = 1.9 Hz, 1H), 7.01 (m, 4H), 6.87 (d, J = 8.4 Hz, 1H), 6.69 (s, 1H), 4.36(t, J = 6.2 Hz (2H), 4.27 (m, 2H), 4.15 (m, 4H), 3.90 (m, 4H), 3.67-3.40 (m, 22H), 3.13 (s, 2H), 2.91 (m, 2H), 2.75 (m, 2H), 2.47 (m, 2H), 2.28 (m, 2H), 2.20 (m, 6H), 1.79-1.71 (m, 4H), 1.56-1.49 (m, 8H), 1.36-1.19 (m, 32H). Mass spectra are shown in [reference needed]. Figure 17 HRMS: m / z calcd for C 69 H 111 N2O 15, 1207.7979 [M – PF6] + ; found 1207.7960 [M– PF6] + . Step 2: Dissolve the [2] rotaxane obtained in Step 1 in N,N-dimethylformamide at a concentration of 5 mg / mL, take 5 mL and soak the graphene oxide film in an 80 °C environment for 12 hours.

[0041] Step 3: Wash the graphene oxide film obtained in step 2 with anhydrous ethanol to remove unreacted [2] rotaxane, and then dry the washed graphene oxide film in a vacuum oven at 45 °C for 4 hours.

[0042] Step 4: Soak the graphene oxide film obtained in step 3 in hydroiodic acid. After 3 hours, wash with anhydrous ethanol to remove the hydroiodic acid. Then, place the washed graphene film in a vacuum oven at 45 °C and dry for 4 hours.

[0043] The tensile stress-strain curve of the graphene film prepared in Example 2 is shown in Figure 2. Figure 9 As shown, this demonstrates that it possesses excellent mechanical tensile properties.

[0044] Example 3 This embodiment provides a method for preparing a graphene thin film material reinforced and toughened using mechanical bonds. Specifically, it includes the following steps: Step 1: Design and synthesize hydroxyl-containing hydroxyl-containing hydroxyl groups, such as... Figure 1 As shown in c, the synthesis method and corresponding spectra are detailed in [reference needed]. J. Am. Chem. Soc. 2023, 145 (16), 9011-9020.

[0045] Step 2: Dissolve the hydroxyl group obtained in Step 1 in chloroform to a concentration of 5 mg / mL, take 5 mL and soak the graphene oxide film in it for 3 hours at 25 °C.

[0046] Step 3: Add 10 mg of 4-dimethylaminopyridine and 10 mg of dicyclohexylcarbodiimide to the chloroform film soaked in Step 2, and continue to maintain the mixture at 25 °C for 3 hours.

[0047] Step 4: Wash the graphene oxide film obtained in step 3 with anhydrous ethanol to remove unreacted hydroxyl groups, 4-dimethylaminopyridine and dicyclohexylcarbodiimide, and then dry the washed graphene oxide film in a vacuum oven at 45 °C for 4 hours.

[0048] Step 5: Soak the graphene oxide film obtained in step 4 in hydroiodic acid. After 3 hours, wash with anhydrous ethanol to remove the hydroiodic acid. Then, place the washed graphene film in a vacuum oven at 45 °C and dry for 4 hours.

[0049] Figure 10 The image shows a photograph of the graphene film prepared in Example 3 being bent into a windmill, demonstrating that the graphene film has excellent flexibility.

[0050] Example 4 This embodiment provides a method for preparing a graphene thin film material reinforced and toughened using mechanical bonds. Specifically, it includes the following steps: Step 1: Design and synthesize hydroxyl-containing daisy chains, such as Figure 1 As shown in d, the synthesis steps are as follows: Figure 18 (The final product can be obtained by proportionally increasing or decreasing the amounts of reactants according to the synthetic route.) The proton NMR spectrum is shown below. Figure 19 , 1 H NMR((CD3)2S=O, 298 K, 400 MHz) δ (ppm): 7.57 (dd, J = 8.5, 1.9 Hz, 1H), 7.46 (d, J =1.9 Hz, 1H), 7.37 (d, J = 8.4 Hz, 2H), 7.09 (d, J = 8.6 Hz, 1H), 6.97 (d, J = 8.5Hz, 2H), 4.23 (t, J = 6.5 Hz, 2H), 4.17 (t, J = 3.8 Hz, 2H), 4.13 (t, J = 4.0 Hz,2H), 4.01 (s, 2H), 3.96 (t, J = 6.4 Hz, 2H), 3.80-3.77 (m, 4H), 3.64-3.61 (m,4H), 3.58-3.55 (m, 4H), 3.84-3.48 (m, 12H), 3.37 (t, J = 6.4 Hz, 2H), 2.81 (t, J = 7.7 Hz, 2H), 1.73-1.66 (m, 4H), 1.56 (t, J= 5.9 Hz, 2H), 1.41–1.37 (m, 6H), 1.33–1.23 (m, 20H). Mass spectra are shown in [reference needed]. Figure 20 HRMS: m / z calcd for C 48 H 80 NO 12 , 862.5675 [M –PF6] + ; found 862.5672 [M – PF6] + . Step 2: Dissolve the daisy chain obtained in Step 1 in N,N-dimethylacetamide at a concentration of 5 mg / mL, take 5 mL and soak the graphene oxide film in it at 25 °C for 3 hours.

[0051] Step 3: Add 10 mg of 4-dimethylaminopyridine and 10 mg of dicyclohexylcarbodiimide to N,N-dimethylacetamide soaked in graphene oxide film in step 2, and continue to maintain at 25 °C for 3 hours.

[0052] Step 4: Wash the graphene oxide film obtained in step 3 with anhydrous ethanol to remove unreacted daisy chains, 4-dimethylaminopyridine and dicyclohexylcarbodiimide, and then dry the washed graphene oxide film in a vacuum oven at 45 °C for 4 hours.

[0053] Step 5: Soak the graphene oxide film obtained in step 4 in hydroiodic acid. After 3 hours, wash with anhydrous ethanol to remove the hydroiodic acid. Then, place the washed graphene film in a vacuum oven at 45 °C and dry for 4 hours.

[0054] The tensile stress-strain curve of the graphene film prepared in Example 4 is shown below. Figure 11 As shown, this demonstrates that it possesses excellent mechanical tensile properties.

[0055] This invention utilizes mechanical bonds to reinforce and toughen graphene films. Mechanically interlocked molecules are effectively introduced into the film through organic solvent immersion and reactions between functional groups. Following reduction with hydroiodic acid, a mechanically bonded graphene film material is obtained. The most prominent characteristic of mechanical bonds is intramolecular motion; that is, under the action of external force, non-dissociative intramolecular motion can occur between the interlocked components, endowing the mechanically interlocked molecules with dynamism and stability. This invention utilizes the unique intramolecular motion of mechanical bonds to prepare stretchable and flexible graphene films with elongation exceeding 20%, which is beneficial for the application of graphene films in flexible electronics. Furthermore, the required mechanically interlocked molecules can be designed as needed, thus this method has universal applicability.

[0056] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A method for preparing a graphene thin film material reinforced and toughened by mechanical bonds, characterized in that, The method includes the following steps: S1. Synthesize a bifunctional mechanically interlocked molecule; wherein the bifunctional mechanically interlocked molecule contains two functional groups; the two functional groups may be the same or different; the functional group is selected from hydroxyl and epoxy groups; the mechanically interlocked molecule is at least one of rotaxane, sesquicarbon, and daisy chain; S2. Dissolve the mechanically interlocked molecules obtained in step S1 in an organic solvent and soak the graphene oxide film; the functional groups of the mechanically interlocked molecules and the oxygen-containing functional groups on the surface of graphene oxide mainly undergo a reaction to form covalent bonds. S3. The graphene oxide film material obtained in step S2 is washed and dried. S4. The graphene oxide film obtained in step S3 is soaked in hydroiodic acid, and after washing and drying, a mechanically bond-reinforced and toughened graphene film material is obtained. The intramolecular motion of the mechanical bonds is used to enhance and toughen the graphene film material.

2. The method for preparing graphene film material reinforced and toughened by mechanical bonds according to claim 1, characterized in that, The reactions that form covalent bonds include esterification and / or epoxy ring-opening reactions.

3. The method for preparing graphene film material reinforced and toughened by mechanical bonds according to claim 1, characterized in that, When the functional group carried by the mechanically interlocking molecule is a hydroxyl group, the reaction of the covalent bond is an esterification reaction, and a reagent that helps the mechanically interlocking molecule and graphene oxide to bind is added to the organic solvent in step S2.

4. The method for preparing graphene film material reinforced and toughened by mechanical bonds according to claim 3, characterized in that, The reagent includes at least one of a catalyst and a coupling agent; the coupling agent is selected from one of dicyclohexylcarbodiimide, N,N'-diisopropylcarbodiimide, and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide; and the catalyst is selected from one of 4-dimethylaminopyridine, 1,8-diazabicyclo[5.4.0]undec-7-ene, and 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

5. The method for preparing graphene film material reinforced and toughened by mechanical bonds according to claim 1, characterized in that, In step S2, the surface of the graphene oxide film has oxygen-containing functional groups; the oxygen-containing functional groups include one or more of hydroxyl, carboxyl, and epoxy groups.

6. The method for preparing graphene film material reinforced and toughened by mechanical bonds according to claim 1, characterized in that, In step S2, the organic solvent is selected from at least one of tetrahydrofuran, N,N-dimethylformamide, N,N-dimethylacetamide, dichloromethane, chloroform, and dimethyl sulfoxide.

7. A mechanically bond-reinforced and toughened graphene film material prepared by the method according to any one of claims 1-6.

8. The use of a mechanically bond-reinforced and toughened graphene thin film material prepared by any one of claims 1-6 in the fabrication of flexible electronic devices.

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