Multivariable regulation and control method for thermal conductivity of graphene film and application of multivariable regulation and control method
By controlling the sheet size and number of layers of the graphene film and combining multiple bending and strain loading, a multivariate correlation model with thermal conductivity was established, which solved the problem of regulating the thermal conductivity of the graphene film and achieved the expansion of its application in flexible electronic devices, wearable devices and heat dissipation materials.
Patent Information
- Application Number
- CN202510840970.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-23
- Publication Date
- 2025-09-16
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of graphene material performance regulation, and more specifically, relates to a multivariable regulation method for the thermal conductivity of a graphene film and its application. Background Art
[0002] Due to its excellent thermal conductivity, graphene shows great potential for application in heat dissipation materials, thermal management devices, and other fields. Existing research has largely focused on the influence of a single factor on the thermal conductivity of graphene films, such as the effect of graphene sheet size or microstructure on thermal conductivity.
[0003] However, in actual application scenarios, especially in flexible electronic devices, wearable devices and other fields, the graphene film will be subjected to multiple mechanical effects such as bending and strain loading at the same time, and its own size and microstructure will also affect the thermal conductivity.
[0004] Currently, there is a lack of systematic research on how the thermal conductivity of graphene films changes under the synergistic effects of multiple variables, such as graphene sheet size, microstructure, multiple bending cycles, and strain loading. This makes it difficult to precisely control the thermal conductivity of graphene films, limiting their application in complex working conditions. Therefore, studying the impact of multiple variables on the thermal conductivity of graphene films and effectively controlling it based on these findings has important theoretical significance and practical application value. Summary of the Invention
[0005] In response to the aforementioned problems with the prior art, the present invention aims to provide a multivariable control method for the thermal conductivity of graphene films to meet the thermal conductivity requirements of graphene films in different application scenarios. The present invention also provides graphene produced by the above method. The present invention also provides the use of graphene films in the preparation of flexible electronic devices, wearable devices, or heat dissipation materials.
[0006] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:
[0007] A multivariable control method for the thermal conductivity of a graphene film comprises the following steps:
[0008] 1) Graphene films with different sheet sizes and number of layers were prepared by chemical vapor deposition (CVD) by controlling the growth temperature, time, and carbon source concentration.
[0009] 2) applying multiple bending and strain loading to the prepared graphene film;
[0010] 3) Use the 3ω method or laser flash method to measure the thermal conductivity of the graphene film treated with different parameters and record the data.
[0011] Preferably, in the step 2), during the multiple bending, the bending angle is 30° to 180°, the number of bending times is 100 to 1000 times, and the strain range of the strain loading is 0 to 10%.
[0012] Preferably, when the thermal conductivity of the graphene film needs to be improved, the method includes: screening out graphene films with a sheet size greater than 50 μm and a layer number of 1 to 2 layers from the graphene film prepared in step 1), and controlling the multiple bending in step 2) to no more than 100 times and the strain amount of the strain loading to no more than 1%.
[0013] Preferably, when it is necessary to reduce the thermal conductivity of the graphene film, the method includes: screening out graphene films with a sheet size of less than 20 μm and a layer number of 3 to 5 layers from the graphene film prepared in step 1), and controlling the multiple bending in step 2) to be greater than 100 times and the strain amount of the strain loading to be greater than 1%.
[0014] Preferably, in the step 1), when the graphene film is prepared by chemical vapor deposition, the growth temperature is 900-1000° C., the growth time is 30-90 min, and the methane concentration is 5%-15%.
[0015] A graphene film thermal conductivity control device includes the following modules:
[0016] The mechanical load application module is used to apply bending and strain loading to the graphene film. The bending angle can be adjusted within the range of 30° to 180°, and the strain can be adjusted within the range of 0 to 10%.
[0017] The thermal conductivity measurement module is used to measure the thermal conductivity of the graphene film using the 3ω method or the laser flash method;
[0018] The control module is used to control the operation of the mechanical load application module and the thermal conductivity measurement module, analyze and process the measurement data, and establish a correlation model between multiple variables and thermal conductivity.
[0019] Preferably, a temperature control module is further included to control the temperature of the environment in which the graphene film is located, and the temperature control range is 100 to 300°C.
[0020] The graphene film is prepared by the multivariable control method of the thermal conductivity of the graphene film.
[0021] The graphene film is used in the preparation of flexible electronic devices, wearable devices or heat dissipation materials.
[0022] Compared with the prior art, the present invention has the following beneficial effects:
[0023] 1) This paper systematically studies for the first time the effects of multiple variables, including graphene sheet size, microstructure, multiple bending, and strain loading, on the thermal conductivity of graphene films. This fills a gap in the study of multivariate synergy in this field and provides a theoretical basis for a deeper understanding of the influencing mechanism of graphene film thermal conductivity.
[0024] 2) The present invention provides a highly operational method for regulating the thermal conductivity of graphene films, which can accurately regulate the thermal conductivity of graphene films according to actual application requirements, expand the application scope of graphene films in flexible electronic devices, wearable devices, heat dissipation materials and other fields, and has significant economic and social value. DETAILED DESCRIPTION
[0025] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described below in conjunction with specific examples. In the following examples, unless otherwise specified, the technical means used are conventional means well known to those skilled in the art. In the examples, if specific conditions are not specified, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, and are all conventional products that can be purchased commercially.
[0026] Example 1
[0027] 1. Preparation of graphene film
[0028] Using the chemical vapor deposition (CVD) method, a graphene film sample A1 with a sheet size of 30 μm and 2 layers was prepared on a copper foil substrate with methane as the carbon source at a growth temperature of 1000°C, a growth time of 30 min, and a methane concentration of 5%. Only the growth time was changed to 60 min, and the other parameters and preparation steps were the same as those of the graphene film sample A1, to obtain a graphene film sample A2 with a sheet size of 60 μm and 2 layers. By mechanical stripping, a graphene film sample B1 with a sheet size of 15 μm and 3 layers was obtained.
[0029] 2. Apply multiple bending and strain loading
[0030] Samples A1, A2, and B1 were placed in a bending tester and bent 300 times at a 90° angle to obtain samples A1-1, A2-1, and B1-1. They were then bent 500 times at a 120° angle to obtain samples A1-2, A2-2, and B1-2. Using a tensile testing machine, a 3% strain load was applied to samples A1, A2, and B1, respectively, to obtain samples A1-3, A2-3, and B1-3. A further 6% strain load was applied to obtain samples A1-4, A2-4, and B1-4. The thermal conductivity of all these samples was measured using a 3ω thermal conductivity tester. The specific measurement data are shown in Table 1.
[0031] Table 1 Thermal conductivity results of different samples
[0032]
[0033]
[0034] Table 1 shows that the thermal conductivity of the graphene film increases with increasing graphene sheet size. Repeated bending and strain loading lead to a decrease in the thermal conductivity of the graphene film, with the decrease becoming more pronounced with increasing bending angles, increasing the number of bends, and increasing the degree of strain loading. Simultaneous application of bending and strain (B1-4) causes the thermal conductivity to drop to 600 W / m·K, exceeding the combined effect of each individual load, indicating that the synergistic effect of multiple loads accelerates the degradation of graphene's thermal conductivity.
[0035] Example 2 (Improving thermal conductivity of graphene film)
[0036] Graphene film sample C, with a single layer and a flake size of 80 μm, was produced on a copper foil substrate using CVD with methane as the carbon source at a growth temperature of 1000°C, a growth time of 90 minutes, and a methane concentration of 8%. The thermal conductivity of graphene film sample C was measured using a 3ω thermal conductivity meter and was found to be 2050 W / m·K. Compared to graphene film sample A1 produced in Example 1, the thermal conductivity increased by 36.7% with the flake size increased from 30 μm to 80 μm.
[0037] Example 3 (Reducing the thermal conductivity of graphene film)
[0038] 1. Preparation of graphene film
[0039] Using the CVD method, methane was used as the carbon source on a copper foil substrate. The growth conditions were: growth temperature 900°C, growth time 20 minutes, methane concentration 15%, and oxygen was introduced for 5 minutes during the growth process to artificially introduce oxidation defects. Graphene film sample D with a sheet size of 15μm and 4 layers was produced.
[0040] 2. Apply multiple bending and strain loading:
[0041] The prepared sample D was placed in a bending test apparatus and bent 800 times at a 150° angle to obtain sample D-1. Using a tensile testing machine, strains of 2%, 4%, 6%, and 8% were applied to sample D, yielding samples D-2%, D-4%, D-6%, and D-8%. The thermal conductivity of all these samples was measured using a 3ω thermal conductivity tester. The measured data are shown in Table 2.
[0042] Table 2 Thermal conductivity results of different samples
[0043]
[0044] Table 2 shows that the thermal conductivity of the prepared graphene film sample D exhibits a nearly linear decay relationship with strain. Compared with the graphene film sample A1 prepared in Example 1, the thermal conductivity decreases by 20% when the sheet size decreases from 30 μm to 15 μm. This indicates that the small size (15 μm) and multilayer (4-layer) structure affect the decrease in thermal conductivity, confirming the effectiveness of multivariable coordinated regulation.
[0045] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.
Claims
1. A multivariable control method for thermal conductivity of a graphene film, characterized in that: The following steps are involved: 1) Graphene films with different sheet sizes and number of layers were prepared by chemical vapor deposition (CVD) by controlling the growth temperature, time, and carbon source concentration. 2) applying multiple bending and strain loading to the prepared graphene film; 3) Use the 3ω method or laser flash method to measure the thermal conductivity of the graphene film treated with different parameters and record the data.
2. The multivariable control method for thermal conductivity of a graphene film according to claim 1, characterized in that: In the step 2), during the multiple bending, the bending angle is 30° to 180°, the number of bending times is 100 to 1000 times, and the strain range of the strain loading is 0 to 10%.
3. The multivariable control method for thermal conductivity of a graphene film according to claim 1, characterized in that: When the thermal conductivity of the graphene film needs to be improved, the method includes: screening out graphene films with a sheet size greater than 50 μm and 1 to 2 layers from the graphene film prepared in step 1), controlling the multiple bending in step 2) to no more than 100 times and the strain amount of the strain loading to no more than 1%.
4. The multivariable control method for thermal conductivity of a graphene film according to claim 1, characterized in that: When it is necessary to reduce the thermal conductivity of the graphene film, the method includes: screening out graphene films with a sheet size of less than 20 μm and a layer number of 3 to 5 layers from the graphene film prepared in step 1), and controlling the multiple bending in step 2) to be greater than 100 times and the strain amount of the strain loading to be greater than 1%.
5. The multivariable control method for thermal conductivity of a graphene film according to claim 1, characterized in that: In the step 1), when the graphene film is prepared by chemical vapor deposition, the growth temperature is 900-1000° C., the growth time is 30-90 minutes, and the methane concentration is 5%-15%.
6. A graphene film thermal conductivity control device, characterized in that: Includes the following modules: The mechanical load application module is used to apply bending and strain loading to the graphene film. The bending angle can be adjusted within the range of 30° to 180°, and the strain can be adjusted within the range of 0 to 10%. The thermal conductivity measurement module is used to measure the thermal conductivity of the graphene film using the 3ω method or the laser flash method; The control module is used to control the operation of the mechanical load application module and the thermal conductivity measurement module, analyze and process the measurement data, and establish a correlation model between multiple variables and thermal conductivity.
7. The graphene film thermal conductivity control device according to claim 6, characterized in that: It also includes a temperature control module for controlling the temperature of the environment in which the graphene film is located, and the temperature control range is 100 to 300°C.
8. A graphene film prepared by the multivariable control method for thermal conductivity of a graphene film according to any one of claims 1 to 5.
9. Use of the graphene film according to claim 8 in the preparation of flexible electronic devices, wearable devices or heat dissipation materials.