Thermally conductive polyimide film: a better heat dissipation material for electronic equipment

Recently, researcher Tian Xingyou and Associate Researcher Zhang Xian of the Department of Polymer and Composite Materials Research, Hefei Research Institute, Chinese Academy of Sciences have made new progress in the research of high thermal conductivity polyimide insulating composite films, and induced nanocarbon nitride through thermal imidization In-plane orientation realizes the construction of high thermal conductivity polyimide insulating film, and based on experimental and theoretical calculation results, it is found that the in-plane orientation of carbon nitride nanosheets and the greatly reduced interface thermal resistance improve the thermal conductivity of polyimide Key factors
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The related results were published in the material science TOP journal "Composites Part B: Engineering" (COMPOS PART B-ENG, 199 (2020) with the title "Imidization-induced carbon nitride nanosheets orientation towards highly thermally conductive polyimide film with superior flexibility and electrical insulation" 108267) on
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With the development of electronic devices in the direction of miniaturization, multi-function and high frequency, the problem of internal heat accumulation has become more and more prominent.
In order to maintain the normal operation and long-term effectiveness of electronic devices, efficient thermal management is very important.
Necessary
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At present, in the field of microelectronic packaging, polyimide (PI) film is considered an ideal material for flexible substrates
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However, due to its low thermal conductivity, polyimide usually needs to be combined with highly thermally conductive inorganic fillers to improve the thermal conductivity of polyimide films by constructing continuous microscopic thermal conduction paths and reducing interface thermal resistance
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However, the current construction method of orderly heat conduction path usually has a series of problems such as complicated process, time-consuming and high cost, which limits the large-scale application
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At the same time, considering the insulation requirements of the PI film and the film forming process, general ceramic thermally conductive fillers or carbon materials cannot be used in the preparation of thermally conductive films
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Therefore, looking for new thermal conductive fillers and simple and effective thermal structure design methods are urgent problems to be solved to improve the thermal conductivity of polyimide film.

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Based on the good graphitized structure and insulating properties of PI film, team members used carbon nitride nanosheets that are widely used in the field of photocatalysis to conduct the first heat conduction application research in PI film
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First, the carbon nitride nanosheets are obtained by thermal etching, then the carbon nitride nanosheets are uniformly mixed with polyamic acid, and finally a polyimide insulating film with high thermal conductivity is prepared by the casting method
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While preparing the PI film by thermal imidization, the carbon nitride nanosheets are simultaneously induced to realize the in-plane orientation arrangement and the construction of the heat conduction network
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With the introduction of carbon nitride nanosheets, the thermal conductivity of the composite film has been greatly improved, from 0.
18 Wm-1K-1 to 2.
04 Wm-1K-1; combined with EMT simulation to explore the thermal conductivity of filler and polymer matrix The results show that the interface thermal resistance between the carbon nitride nanosheets and the polyimide matrix is ​​much lower than that reported in the literature.
This is mainly due to the interfacial thermal resistance between the carbon nitride nanosheets and the polyimide molecule.
The strong covalent effect
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In addition, the composite PI film not only greatly improves the thermal conductivity, but also maintains excellent electrical insulation performance, thermal stability and other excellent characteristics, which meets the application needs of electronic packaging materials.
In the future, it will have a wide range of fields such as flexible electronics and insulating medium packaging.
Application prospects
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This work was funded by the National Key Research and Development Program, the STS Key Project of the Chinese Academy of Sciences, and the Anhui Natural Science Foundation
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