Honeycomb array type graphene electrothermal crystal film and preparation method and application thereof

Abstract

The invention relates to a honeycomb array type graphene electrothermal crystal film and a preparation method and application thereof, and the preparation method comprises the following steps: tetracarboxylic dianhydride and diamine are subjected to condensation polymerization to synthesize a polyamide acid solution; curing the polyamide acid solution to form a modified polyimide film, and performing in-situ irradiation on the modified polyimide film under a high-energy beam to obtain graphene which is distributed in a honeycomb array and has a three-dimensional hierarchical porous structure; and connecting the graphene distributed in the honeycomb array in parallel by using a current collector to obtain the graphene electrothermal crystal film. The honeycomb array type graphene electrothermal crystal film prepared by the invention has good electrothermal conversion efficiency, uniform surface heating capability and excellent mechanical properties.

Description

Technical Field

[0001] The present invention relates to the technical field of electrothermal composite materials, and in particular to a honeycomb array graphene electrothermal crystal film and a preparation method and application thereof. Background Art

[0002] Traditional daily electric heating devices have the disadvantages of high energy consumption, short service life, heavy weight, and difficulty in integration. As the use time increases, they face safety hazards such as component aging and short circuits. With the development trend of miniaturization and integration of electronic devices, electric heating devices with the characteristics of "light, thin, and tough" have attracted widespread attention. Graphene has excellent electrical conductivity, high thermal conductivity, Young's modulus, and electrothermal conversion efficiency, showing broad application prospects in the field of electrothermal conversion.

[0003] However, due to the π-π long-range conjugated structure, two-dimensional graphene sheets will be stacked, resulting in the attenuation of the inherent properties of graphene. Constructing graphene with a three-dimensional network support structure can not only effectively avoid sheet stacking, but also retain the inherent properties of graphene. However, in the traditional graphene preparation method, either wet chemical method is used, which requires strong acid or strong oxidant to participate in the reaction, which is easy to introduce impurities and defects, reducing the crystal quality of graphene; or in the reaction chamber, with the assistance of high temperature, high pressure and even ultra-vacuum and other harsh experimental conditions and processes, the prepared graphene needs to undergo additional treatment, and the cost is high, which is not conducive to the large-scale industrial application of graphene. In recent years, the technology of using high-energy beam to irradiate the surface of carbon-containing precursors in situ to prepare three-dimensional graphene has been widely studied. High-energy beam processing technology has a series of advantages such as green environmental protection, high energy density, simple process, good spatial controllability and scalability. It is an ideal choice in the preparation of graphene and its arraying and patterning process. In high-energy beams, graphene prepared using CO2 infrared laser as a low-cost heat source has the advantages of high crystal quality, in-situ large-area preparation, and being green and environmentally friendly.

[0004] However, under voltage drive, due to the interface resistance at the interface between the current collector and graphene, large-area graphene crystal films have longer electron transmission paths and higher resistance, which can lead to uneven heating. In addition, the mechanical properties of graphene crystal films need to be further improved in practical applications, especially when integrated with other devices. Summary of the invention

[0005] Based on this, the first object of the present invention is to provide a method for preparing a honeycomb array graphene electrothermal crystal film. The prepared graphene electrothermal crystal film has good electrothermal conversion efficiency, uniform surface heating capability, and excellent mechanical properties.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for preparing a honeycomb array graphene electrothermal crystal film, which comprises the following steps:

[0008] The polyamic acid solution is synthesized by polycondensation reaction of dianhydride and diamine;

[0009] The polyamic acid solution is solidified to form a modified polyimide film, and the modified polyimide film is in-situ irradiated under a high-energy beam to obtain a honeycomb array distributed graphene having a three-dimensional hierarchical porous structure;

[0010] The graphene distributed in the honeycomb array is connected in parallel by using a current collector to obtain a graphene electrothermal crystal film.

[0011] The present invention utilizes dianhydride and diamine to carry out polycondensation reaction to synthesize polyamic acid solution, changes the molecular configuration of polyimide, can form dense chain entanglement between polyimide molecular chains, modifies the molecular structure characteristics of polyimide, effectively improves the mechanical properties of polyimide film, and improves the thermal sensitivity of polyimide, thereby effectively controlling the photothermal response mechanism of high-energy beam to molecules in polyimide, and obtains high-crystal quality graphene, the electron transmission efficiency of graphene is further improved, and when current is input, a large amount of resistive heat is generated in the process of electron movement; at the same time, the graphene is arranged in a honeycomb array, which can achieve higher electric heat exchange efficiency and uniform interface heating.

[0012] As a further improvement of the above scheme of the present invention, the specific steps of the polycondensation reaction are: dissolving the diamine in an organic solvent, stirring evenly, and after it is completely dissolved, slowly adding the dianhydride in batches, reacting in an ice bath for 8 to 12 hours to generate a viscous polyamic acid solution.

[0013] As a further improvement of the above scheme of the present invention, the molar ratio of the diamine to the dianhydride is 1:1 to 5, preferably 1:1.

[0014] As a further improvement of the above scheme of the present invention, the dianhydride is selected from one of tetracarboxylic dianhydride, pyromellitic dianhydride, phthalic anhydride, bisphenol A anhydride, and hexafluoro dianhydride; preferably tetracarboxylic dianhydride.

[0015] As a further improvement of the above scheme of the present invention, the diamine is selected from one of 4,4'-diaminodiphenyl ether, p-phenylenediamine, 3,3',4,4'-tetraaminobiphenyl, 3,3'-diaminodiphenylmethane, 2,2'-diaminobiphenyl, and 4,4'-diaminodiphenylmethane, preferably 4,4'-diaminodiphenyl ether.

[0016] As a further improvement of the above scheme of the present invention, the organic solvent is selected from one of N,N-dimethylacetamide, N,N-dimethylformamide, and N-methylpyrrolidone, preferably N,N-dimethylacetamide.

[0017] As a further improvement of the above scheme of the present invention, the temperature of the ice bath condition is 0-5°C, preferably 0°C.

[0018] As a further improvement of the above scheme of the present invention, the specific steps of curing the polyamic acid solution to form a polyimide film are: uniformly coating the polyamic acid solution on a glass plate, placing it in a blast drying oven and heating it by programmed temperature rise, and forming a modified polyimide film after thermal imidization reaction.

[0019] As a further improvement of the above scheme of the present invention, the programmed temperature heating is carried out at a heating rate of 5°C / min and is kept at 60°C, 80°C, 100°C, 140°C, 180°C, 200°C and 240°C for 1 hour respectively.

[0020] As a further improvement of the above solution of the present invention, the high-energy beam is selected from one of an electron beam, a laser beam and an ion beam.

[0021] As a further improvement of the above scheme of the present invention, during the high-energy beam in-situ irradiation process, the laser power is 8W, the scanning line spacing is 0.12mm, and the scanning speed is 160mm / s; preferably, the high-energy beam is a CO2 infrared laser with a wavelength of 10600nm.

[0022] The second object of the present invention is to provide a honeycomb array graphene electrothermal crystal film, which is prepared by the preparation method as described above.

[0023] The third object of the present invention is to provide an application of the honeycomb array graphene electrothermal crystal film as described above in an electrothermal device.

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

[0025] The present invention uses different dianhydrides and diamines to carry out polycondensation reactions to synthesize polyamic acid solutions according to different needs. The polyamic acid solutions are cured to form modified polyimide films, and the molecular configuration of polyimide is changed, so that dense chain entanglements can be formed between polyimide molecular chains, and the molecular structure characteristics of polyimide are modified, thereby effectively improving the mechanical properties of the polyimide film and improving the thermal sensitivity of the polyimide, thereby effectively controlling the photothermal response mechanism of high-energy beams to molecules in polyimide, obtaining high-crystal quality graphene, further improving the electron transmission efficiency of the graphene, and generating a large amount of resistive heat during the electron movement process when current is input; and at the same time, the graphene is arranged in a honeycomb array, so that higher electric heat exchange efficiency and uniform interface heating can be achieved.

[0026] The honeycomb array graphene electrothermal crystal film provided by the present invention has good electrothermal conversion efficiency, uniform surface heating capability, and excellent mechanical properties, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of assembling a honeycomb array graphene electrothermal crystal film prepared in an embodiment of the present invention;

[0028] Figure 2 The stress-strain curve of the honeycomb array graphene electrothermal crystal film prepared in the embodiment of the present invention;

[0029] Figure 3 This is a thermal infrared image of the honeycomb array graphene electrothermal crystal film produced by the present invention when it reaches the saturation temperature under a voltage of 6V. DETAILED DESCRIPTION

[0030] For ease of understanding of the present invention, the present invention will be described more fully below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0032] Example 1

[0033] This embodiment provides a honeycomb array graphene electrothermal crystal film, and the preparation method thereof includes the following steps:

[0034] (1) 5.6 g of tetracarboxylic dianhydride was dissolved in 100 mL of N,N-dimethylacetamide, and the mixture was uniformly stirred and dissolved in an ice bath. 2.6 g of 4,4'-diaminodiphenyl ether was slowly added in batches within 1 hour. After 10 hours of polycondensation reaction, a viscous polyamic acid solution was generated.

[0035] (2) The polyamic acid solution is uniformly coated on a glass plate, and placed in a programmed temperature-rising forced air drying oven for heating at a heating rate of 5°C / min and kept at 60°C, 80°C, 100°C, 140°C, 180°C, 200°C, and 240°C for 1 h respectively, and the organic solvent is removed. After a thermal imidization reaction, a modified polyimide film is formed.

[0036] (3) After the honeycomb array pattern is designed on the interface of the CO2 laser platform, the modified polyimide film is in-situ irradiated under a CO2 infrared laser with a laser power of 10 W, a scanning line spacing of 0.12 mm, and a scanning speed of 180 mm / s to generate a honeycomb array distributed graphene with a three-dimensional porous structure; combined with Figure 1 , copper paste is coated between adjacent graphene units, and then double-sided conductive copper foil is used to connect adjacent graphene units, which are connected in parallel to form a graphene electrothermal crystal film arranged in a honeycomb array, and finally placed in a forced air drying oven and cured at 100°C for 30 minutes.

[0037] The honeycomb array graphene electrothermal crystal film prepared in this embodiment was subjected to stress-strain test. The test results are as follows: Figure 2 As shown, the test results show that its stress is close to 6MPa, the strain reaches 24%, and the curve shows a linear relationship, showing good elastic behavior, indicating that the graphene electrothermal crystal film has a high plastic deformation ability and can produce a large strain before reaching fracture.

[0038] Figure 3 The corresponding thermal infrared image of the honeycomb array graphene electrothermal crystal film obtained in this embodiment when driven by a voltage of 6V and reaches the saturation temperature (265°C) in 45s. Figure 3 It can be seen that the honeycomb array graphene electrothermal crystal film prepared in this embodiment generates heat evenly.

[0039] Example 2

[0040] This embodiment adopts the same implementation method as that of Embodiment 1, and the difference from Embodiment 1 is that in this embodiment, the molar ratio of tetracarboxylic dianhydride to 4,4'-diaminodiphenyl ether is 1:1.2, that is, the addition amount of tetracarboxylic dianhydride is 6.3 g, and the addition amount of 4,4'-diaminodiphenyl ether is 3.86 g.

[0041] Example 3

[0042] This embodiment adopts the same implementation method as that of Example 1, and the difference from Example 1 is that in this embodiment, p-phenylenediamine is used instead of 4,4'-diaminodiphenyl ether in Example 1, and the molar ratio of tetracarboxylic dianhydride to p-phenylenediamine is 1:1, that is, the addition amount of tetracarboxylic dianhydride is 7.2g, and the addition amount of p-phenylenediamine is 3.63g.

[0043] The honeycomb array graphene electrothermal crystal film prepared in Example 2-3 was tested, and it was found that the honeycomb array graphene electrothermal crystal film prepared in Example 2-3 had the same good electrothermal conversion efficiency, uniform surface heating capability and excellent mechanical properties as Example 1.

[0044] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0045] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing a honeycomb array graphene electrothermal crystal film, characterized in that: It includes the following steps: The polyamic acid solution is synthesized by polycondensation reaction of dianhydride and diamine; The polyamic acid solution is solidified to form a modified polyimide film, and the modified polyimide film is in-situ irradiated under a high-energy beam to obtain a honeycomb array distributed graphene having a three-dimensional hierarchical porous structure; The graphene distributed in the honeycomb array is connected in parallel by using a current collector to obtain a graphene electrothermal crystal film.

2. The method for preparing the honeycomb array graphene electrothermal crystal film according to claim 1, characterized in that: The specific steps of the polycondensation reaction are: dissolving the diamine in an organic solvent, stirring evenly under ice bath conditions, and after the diamine is completely dissolved, slowly adding the dianhydride in batches, reacting for 8 to 12 hours to generate a viscous polyamic acid solution.

3. The method for preparing the honeycomb array graphene electrothermal crystal film according to claim 1, characterized in that: The molar ratio of the diamine to the dianhydride is 1:1-5.

4. The method for preparing the honeycomb array graphene electrothermal crystal film according to claim 1, characterized in that: The dianhydride is selected from one of tetracarboxylic dianhydride, pyromellitic dianhydride, phthalic anhydride, bisphenol A anhydride, and hexafluoro dianhydride; And / or, the diamine is selected from one of 4,4'-diaminodiphenyl ether, p-phenylenediamine, 3,3',4,4'-tetraaminobiphenyl, 3,3'-diaminodiphenylmethane, 2,2'-diaminobiphenyl, and 4,4'-diaminodiphenylmethane.

5. The method for preparing the honeycomb array graphene electrothermal crystal film according to claim 2, characterized in that: The organic solvent is selected from one of N,N-dimethylacetamide, N,N-dimethylformamide and N-methylpyrrolidone; And / or, the temperature of the ice bath condition is 0-5°C.

6. The method for preparing the honeycomb array graphene electrothermal crystal film according to claim 1, characterized in that: The specific steps of curing the polyamic acid solution to form a polyimide film are: uniformly coating the polyamic acid solution on a glass plate, placing it in a programmed temperature-rising forced air drying oven for heating, and forming a modified polyimide film after a thermal imidization reaction.

7. The method for preparing the honeycomb array graphene electrothermal crystal film according to claim 6, characterized in that: The programmed temperature rise process is to heat the temperature at a heating rate of 5°C / min and keep the temperature at 60°C, 80°C, 100°C, 140°C, 180°C, 200°C and 240°C for 1 hour respectively.

8. The method for preparing the honeycomb array graphene electrothermal crystal film according to claim 1, characterized in that: The high energy beam is selected from one of an electron beam, a laser beam and an ion beam; And / or, during the high-energy beam in-situ irradiation process, the laser power is 5 to 12 W, the scanning line spacing is 0.1 to 0.15 mm, and the scanning speed is 120 to 200 mm / s.

9. A honeycomb array graphene electrothermal crystal film, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the honeycomb array graphene electrothermal crystal film as claimed in claim 9 in an electrothermal device.

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