Thermal interface material with local temperature monitoring function and preparation method thereof

Abstract

The invention relates to the technical field of thermal interface materials, in particular to a thermal interface material with a local temperature monitoring function and a preparation method of the thermal interface material. Specifically, the polypyrrole thermal interface material is prepared from the following raw materials: ferric salt, a fiber forming agent, a surfactant and an organic solvent. According to the polypyrrole fiber thermal interface material prepared by adopting magnetic field orientation and freeze drying technologies, the defects of the traditional technology are effectively overcome, the longitudinal heat-conducting property of the material is remarkably improved by realizing directional arrangement of the polypyrrole fibers, and the material is endowed with a local temperature monitoring function in a breakthrough manner; abnormal temperature change of the heat source surface can be captured in real time, the hot spot position can be accurately positioned, and a monitoring blind area caused by temperature difference covered by transverse heat diffusion is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal interface materials, and more specifically, to a thermal interface material with a local temperature monitoring function and a preparation method thereof. Background Art

[0002] With the rapid development of electronic devices towards high performance, high integration and miniaturization, their power density has increased sharply, and the resulting heat accumulation problem has become increasingly prominent, seriously affecting the reliability and service life of the devices. Thermal Interface Materials (TIMs), as the key medium connecting the heat source and the heat sink, play an irreplaceable role in the thermal management of electronic devices by filling the microscopic voids at the contact interface to reduce the interface thermal resistance. In recent years, researchers have significantly improved the longitudinal thermal conductivity of TIMs through strategies such as functionalizing thermal conductive fillers (such as boron nitride, graphene, etc.), constructing oriented structures (such as magnetically oriented carbon fibers), and designing three-dimensional thermal conductive networks. However, existing TIMs generally have a heat lateral diffusion effect, which not only masks the local temperature differences on the surface of the heat source, but also makes it difficult to achieve the real-time monitoring function of temperature anomalies. In the context of the increasingly urgent demand for precise thermal management in intelligent electronic devices, developing a new type of thermal interface material with both high-efficiency heat dissipation and temperature sensing functions has become the key to breaking through the existing technical bottlenecks. The single thermal conduction function of traditional TIMs can no longer meet the requirements of the new generation of electronic devices for thermal failure warning and intelligent regulation, and this technical gap seriously restricts the development of high-reliability electronic systems. Therefore, there is an urgent need to develop a multifunctional thermal interface material with temperature-sensitive characteristics to achieve real-time monitoring and feedback of the local hot spot positions while ensuring high-efficiency heat conduction, providing an innovative solution for the thermal safety management of electronic devices. Summary of the Invention

[0003] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, an object of one aspect of the present invention is to provide a thermal interface material with a local temperature monitoring function, specifically a polypyrrole thermal interface material, and the raw materials are iron salts, fiber-forming agents, surfactants and organic solvents.

[0004] Another object of the present invention is to provide a preparation method of a thermal interface material with a local temperature monitoring function. The specific steps of the preparation method are as follows: S1. Preparation of polypyrrole fibers: Add iron salts and fiber-forming agents into ethanol and N,N-dimethylformamide (DMF) to prepare a spinning solution. Load the solution into a plastic syringe, use a 25-gauge needle, and collect it at a fixed distance under a constant voltage with a constant flow rate for electrospinning. Anneal the electrospun nanofibers in air to obtain hollow magnetic iron oxide nanofibers; Disperse the hollow magnetic iron oxide (Fe3O4) nanofibers as a sacrificial template into deionized water containing a surfactant, and stir vigorously at room temperature to obtain a suspension; Add pyrrole monomers to the suspension and stir further vigorously; Add an oxidant and hydrochloric acid to deionized water, mix and then drop it into the system, and continuously stir gently in a water bath to start the polymerization process. After stirring, the color of the solution turns black, and the reaction is completed. The product is centrifuged, washed with deionized water, and dried in vacuum to obtain polypyrrole fibers; S2. Preparation of polypyrrole thermal interface materials: Add polypyrrole fibers into an organic solvent, stir and mix, then pour the suspension into a polystyrene petri dish with a diameter of 30 mm to form a liquid with a height of about 10 mm, and immediately move it into the magnetic field generated by two neodymium iron boron magnets (length × width × thickness: 45 mm × 45 mm × 20 mm). Due to the anisotropic magnetic susceptibility, the polypyrrole fibers are aligned along the magnetic field during deposition and vertically fall to the bottom of the petri dish. When all the fibers settle to the bottom, place the magnet and the dish on a vibrating platform and vibrate horizontally to make the polypyrrole fibers vertically arranged and stacked. Freeze-dry under the magnetic field to remove the solvent, and heat-treat under inert gas protection; During this process, DMF will sublimate, and the polypyrrole fibers will form a microstructure with vertical arrangement. Mix the a and b components of the addition-type silicone gel evenly to prepare a matrix solution, pour it into the vertical polypyrrole fiber array, and remove bubbles and cure it in a vacuum drying oven to obtain a thermal interface material based on the vertical polypyrrole fiber array.

[0005] Preferably, in S1, the iron salt is one or a combination of more than one of ferric chloride hexahydrate, ferric nitrate hexahydrate, ferrous sulfate, and / or iron acetylacetonate; the fiber-forming agent is one or a combination of more than one of polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol, and / or polyacrylonitrile; the surfactant is one or a combination of more than one of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and / or cetyltrimethylammonium bromide.

[0006] Preferably, in S1, the molar ratio of the iron salt, fiber-forming agent, ethanol, and N,N-dimethylformamide is 1:35:13.7:2.6; the molar ratio of the hollow magnetic iron oxide nanofibers to the surfactant and deionized water is 0.3 - 0.8:1000 - 2000:2780 - 2780; the molar ratio of the oxidant, hydrochloric acid, and deionized water is 5 - 25:3 - 6:69.5 - 139.

[0007] Preferably, in S1, electrospinning is carried out at a voltage of 25 - 30 kV and a collection distance of 20 - 25 cm at a flow rate of 0.5 - 1.0 mL / h. -1 The electrospun nanofibers are annealed in air at 500 °C for 2 h to obtain 0.3 - 0.8 mmol of hollow magnetic iron oxide nanofibers.

[0008] Preferably, in S1, it is vigorously stirred at room temperature for 11 - 12 h to obtain a suspension; pyrrole monomer is added to the suspension and further vigorously stirred for 10 h; the polymerization process is started, and after stirring for 24 h, it is vacuum dried at 60 °C for 24 h to obtain polypyrrole fibers.

[0009] Preferably, in S2, the organic solvent is one or a combination of more of polyvinyl alcohol (PVA), N - methylpyrrolidone (NMP), and / or N, N - dimethylformamide (DMF).

[0010] Preferably, in S2, the molar ratio of the organic solvent to the polypyrrole fibers is 4.6 - 11.8:1, and the concentration of the polypyrrole fibers in the organic solvent varies within the range of 10 - 15 wt%; the inert gas is a mixture of helium and argon with a ratio of 1:19.

[0011] Preferably, in S2, polypyrrole fibers are added to the organic solvent, stirred for 30 min, horizontally vibrated at a frequency of 25 - 30 Hz and an amplitude of 0.5 - 0.6 mm for 1 - 3 min, freeze - dried for 48 - 50 h to remove the solvent, and the freeze - dried sample is heat - treated at 180 °C under a 5% mixture of helium and argon for 3 h.

[0012] Preferably, in S2, the addition - type silicone gel a and b components are mixed evenly in a ratio of 1:1 to prepare a matrix solution; it is cured at 140 °C for 6 h.

[0013] The beneficial effects of the present invention are as follows: The polypyrrole fiber thermal interface material prepared by the present invention using magnetic field orientation and freeze - drying technology effectively overcomes the shortcomings of traditional technologies. By realizing the oriented arrangement of polypyrrole fibers, it not only significantly improves the longitudinal thermal conductivity of the material, but also breakthroughly endows it with the function of local temperature monitoring, which can capture the abnormal temperature changes on the surface of the heat source in real time, accurately locate the hot spot position, and avoid the monitoring blind area caused by the lateral diffusion of heat covering the temperature difference. It breaks the limitation of the single heat conduction of traditional thermal interface materials, realizes the dual - function integration of heat dissipation and sensing, can provide thermal failure warning and intelligent regulation support for intelligent electronic devices, greatly improves the reliability and service life of the electronic system, provides an innovative solution for the thermal safety management of highly integrated and miniaturized electronic devices, and effectively fills the gap in the field of temperature - sensitive monitoring in the existing technology.

[0014] Additional aspects and advantages of the present invention will become apparent in the following description or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of embodiments in conjunction with the following drawings, where: Figure 1 is the SEM image of polypyrrole fibers in an embodiment of the present invention; Figure 2 is the SEM image of polypyrrole fibers after freeze-drying in an embodiment of the present invention; Figure 3 is the application schematic diagram of an embodiment of the present invention; Figure 4 is the temperature monitoring diagram of the freeze-dried carbon fiber thermal interface material in an embodiment of the present invention; Figure 5 is the temperature monitoring diagram of the alumina thermal interface material in an embodiment of the present invention; Figure 6 is the temperature monitoring diagram of the carbon fiber thermal interface material without freeze-drying in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0016] In order to more clearly understand the above objects, features, and advantages of the present invention, the present invention will be further described in detail below in conjunction with the drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments may be combined with each other.

[0017] Many specific details are set forth in the following description in order to fully understand the present invention. However, the present invention may be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0018] Embodiment 1 Dissolve 1 g of ferric chloride (FeCl3•6H2O) and 4 g of polyvinylpyrrolidone (PVP) in a solution composed of 8 mL of ethanol and 2 mL of dimethylformamide (DMF), stir to obtain a homogeneous solution, fill the solution into a plastic syringe, use a 25-gauge needle, and at a voltage of 30 kV and a collection distance of 15 cm, at a rate of 1.0 mL / h -1Electrospinning was carried out at a flow rate of ; the electrospun nanofibers were annealed in air at 500 °C for 2 h to obtain hollow Fe2O3 nanofibers; 0.3 mmol of the obtained hollow Fe2O3 nanofibers were dispersed as a sacrificial template into 10 mL of deionized water containing 1.5 mol of sodium dodecylbenzenesulfonate (SDBS), and vigorously stirred at room temperature for 12 h; 0.1 mmol of pyrrole monomer was added to the suspension, and further vigorously stirred for 12 h; 10 mL of HCl aqueous solution was dropped into the system, and gently stirred continuously in an ice / water bath to initiate the polymerization process; after stirring for 10 h, the color of the solution turned black, indicating the completion of the reaction. The product was centrifuged, washed several times with deionized water, and vacuum dried at 60 °C for 24 h to obtain polypyrrole fibers.

[0019] 1 g of polypyrrole fibers was dissolved in 5 g of DMF, stirred for 30 min to disperse evenly, the concentration of polypyrrole fibers in the solution varied in the range of 5 - 10 wt%, and the mass ratio of polypyrrole fibers to DMF was kept constant at 1:5. After mixing, the suspension was poured into a polystyrene Petri dish with a diameter of 30 mm to form a liquid with a height of about 10 mm, and immediately moved to the magnetic field generated by two commercially available neodymium iron boron magnets (length × width × thickness: 45 mm × 45 mm × 20 mm). Due to the anisotropic magnetic susceptibility, the polypyrrole fibers were aligned along the magnetic field during the deposition process and vertically landed on the bottom of the Petri dish; when all the fibers settled to the bottom, the magnet and the dish were placed on a vibrating platform and horizontally vibrated at a frequency of 25 Hz and an amplitude of 0.5 mm for 1 min to make the fibers closely packed. The mixture was freeze-dried in the magnetic field for 48 h to remove the solvent, and the freeze-dried sample was heat-treated at 180 °C under a 5% helium / argon mixture for 3 h. During this process, DMF would sublime, and the polypyrrole fibers would form a microstructure with vertical alignment. The addition-type silicone gel a and b components were mixed evenly according to a ratio of 1:1 to prepare a matrix solution. The evenly mixed solution was poured into the vertical polypyrrole fiber array, and the bubbles were removed in a vacuum drying oven. The sample was cured at 140 °C for 6 h to obtain a thermal interface material based on the vertical polypyrrole fiber array.

[0020] Example 2 1 g of iron(III) nitrate hexahydrate (FeNO3•6H2O) and 4.6 g of polyacrylonitrile were dissolved in a solution composed of 8 mL of ethanol and 2 mL of dimethylformamide (DMF), stirred to obtain a homogeneous solution, the solution was loaded into a plastic syringe, a 25-gauge needle was used, and at a voltage of 30 kV and a collection distance of 15 cm, at a rate of 1.0 mL / h -1Electrospinning was carried out at a flow rate of , and the electrospun nanofibers were annealed in air at 500 °C for 2 h to obtain hollow Fe2O3 nanofibers. 0.3 mmol of the obtained hollow Fe2O3 nanofibers were dispersed as a sacrificial template into 10 mL of deionized water containing 1.5 mol of sodium dodecylbenzenesulfonate (SDBS), and vigorously stirred at room temperature for 12 h. 0.1 mmol of pyrrole monomer was added to the suspension, and further vigorously stirred for 12 h. 10 mL of HCl aqueous solution was dropped into the system, and gently stirred continuously in an ice / water bath to initiate the polymerization process. After stirring for 10 h, the solution color turned black, indicating the completion of the reaction. The product was centrifuged, washed several times with deionized water, and vacuum dried at 60 °C for 24 h to obtain polypyrrole fibers.

[0021] 1 g of polyvinyl alcohol (PVA) was dissolved in 19 g of deionized water, and stirred at 80 - 90 °C for 60 - 90 min to form a PVA solution. Then 1 g of polypyrrole fibers was added and stirred for 30 min to disperse them. The concentration of polypyrrole fibers in the PVA solution varied in the range of 10 - 15 wt%, and the mass ratio of polypyrrole fibers to PVA was kept constant at 20:1. After mixing, the suspension was poured into a polystyrene petri dish with a diameter of 30 mm to form a liquid with a height of about 10 mm, and immediately moved into the magnetic field generated by two commercially available neodymium iron boron magnets (length × width × thickness: 45 mm × 45 mm × 20 mm). Due to the anisotropic magnetic susceptibility, the polypyrrole fibers were aligned along the magnetic field during the deposition process and vertically landed on the bottom of the petri dish. When all the fibers settled to the bottom, the magnet and the dish were placed on a vibrating platform and horizontally vibrated at a frequency of 25 - 30 Hz and an amplitude of 0.5 - 0.6 mm for 1 - 3 min to vertically stack the polypyrrole fibers. The mixture was freeze-dried in the magnetic field for 48 h to remove the solvent. The freeze-dried sample was heat-treated at 180 °C under a 5% helium / argon mixture for 3 h. During this process, PVA would sublime, and the polypyrrole fibers would form a microstructure with vertical alignment. The addition-type silicone gel a and b components were mixed evenly according to a ratio of 1:1 to prepare a matrix solution. The evenly mixed matrix solution was poured into the vertical polypyrrole fiber array, and the bubbles were removed in a vacuum drying oven. The sample was cured at 140 °C for 6 h to obtain a thermal interface material based on the vertical polypyrrole fiber array.

[0022] Example 3 1 g of ferrous sulfate and 4.6 g of polyvinylpyrrolidone were dissolved in a solution composed of 8 mL of ethanol and 2 mL of dimethylformamide (DMF), and stirred to obtain a homogeneous solution. The solution was loaded into a plastic syringe, and using a 25-gauge needle, at a voltage of 30 kV and a collection distance of 15 cm, at a rate of 1.0 mLh -1Electrospinning was carried out at a flow rate of , and the electrospun nanofibers were annealed in air at 500 °C for 2 h to obtain hollow Fe2O3 nanofibers. 0.3 mmol of the obtained hollow Fe2O3 nanofibers were dispersed as a sacrificial template into 10 mL of deionized water containing 1.5 mol of sodium dodecyl sulfate, and vigorously stirred at room temperature for 12 h. 0.1 mmol of pyrrole monomer was added to the suspension, and the solution was further vigorously stirred for 12 h. 10 mL of HCl aqueous solution was dropped into the system, and gently stirred continuously in an ice / water bath to start the polymerization process. After stirring for 10 h, the solution color changed to black, indicating that the reaction was completed. The product was centrifuged, washed several times with deionized water, and vacuum dried at 60 °C for 24 h to obtain polypyrrole fibers.

[0023] 20 g of N-methylpyrrolidone (NMP) was added to 1 g of polypyrrole fibers and stirred for 30 min to disperse them. The concentration of polypyrrole fibers in the solution varied in the range of 10-15 wt%, and the mass ratio of polypyrrole fibers to NMP was kept constant at 20:1. After mixing, the suspension was poured into a polystyrene petri dish with a diameter of 30 mm to form a liquid with a height of about 10 mm, and immediately moved into the magnetic field generated by two commercially available neodymium iron boron magnets (length × width × thickness: 45 mm × 45 mm × 20 mm). Due to the anisotropic magnetic susceptibility, the polypyrrole fibers aligned along the magnetic field during deposition and vertically landed on the bottom of the petri dish. When all the fibers settled to the bottom, the magnet and the dish were placed on a vibrating platform and horizontally vibrated at a frequency of 25-30 Hz and an amplitude of 0.5-0.6 mm for 1-3 min to vertically stack the polypyrrole fibers. The mixture was freeze-dried under the magnetic field for 48 h to remove the solvent. The freeze-dried sample was heat-treated at 180 °C under a 5% helium / argon mixture for 3 h. During this process, PVA would sublime, and the polypyrrole fibers would form a microstructure with vertical alignment. The addition-type silicone gel a and b components were mixed evenly according to a ratio of 1:1 to prepare a matrix solution. The evenly mixed matrix solution was poured into the vertical polypyrrole fiber array, and the bubbles were removed in a vacuum drying oven. The sample was cured at 140 °C for 6 h to obtain a thermal interface material based on the vertical polypyrrole fiber array.

[0024] Figure 1 and Figure 2 are the SEM images of polypyrrole fibers and freeze-dried polypyrrole fibers.

[0025] Application A local temperature monitoring device was fabricated with a circuit made of silver paste, and a heating resistor was simulated with carbon paste. It consists of a circuit, a thermal interface material, an infrared camera, a power supply, and a display, as shown in Figure 3As shown in the figure. Local temperature monitoring device: The heat source is composed of a silver paste circuit and a carbon paste circuit. An external power supply applies a voltage. Due to the different resistances of the silver paste circuit and the carbon paste circuit, local hot spots will be generated when the voltage is applied. Attach the thermal interface material to the heat source, and directly observe the temperature change with an infrared thermal imager, or transmit the temperature change signal through the temperature sensor outside the thermal interface material to the analog-to-digital conversion microcontroller after processing the analog signal through a voltage divider to convert the analog signal into a digital signal, and then transmit it to the computer through the local area network. Place the polypyrrole thermal interface material on the printed circuit and gently press it by hand to make the sample close to the circuit. The power supply provides appropriate voltage and current, and use an infrared camera to observe the temperature distribution on the surface of the sample. Due to the different resistances of the silver paste circuit and the carbon paste circuit, local hot spots will be generated when the voltage is applied. Infrared imaging tests show that the temperatures at two high-resistance positions (spots printed with carbon paste) on the substrate surface are significantly higher than those of the low-resistance silver circuit. Attach the polypyrrole thermal interface material to the surface of the heat source, and infrared temperature tests show that three high-temperature points quickly appear at the positions corresponding to the three hot spots of the heat source on the surface of the polypyrrole thermal interface material. Based on the polypyrrole thermal interface material, high-temperature spots on the substrate can be accurately detected.

[0026] Comparative Experiment 1 Place the polypyrrole thermal interface material and the alumina thermal interface material on the printed circuit in sequence and gently press it by hand to make the sample close to the circuit. Attach the polypyrrole thermal interface material to the surface of the heat source. Infrared temperature tests show that two high-temperature points quickly appear at the positions corresponding to the two hot spots of the heat source on the surface of the polypyrrole thermal interface material (as Figure 4 shown). On the contrary, no high-temperature spots at the bottom are detected on the surface of the alumina thermal interface material (as Figure 5 shown).

[0027] Comparative Experiment 2 Place the carbon fiber thermal interface material without freeze-drying on the printed circuit and gently press it by hand to make the sample close to the circuit. No high-temperature spots at the bottom are detected on the surface of the carbon fiber thermal interface material (as Figure 6 shown).

[0028] The above is only the preferred embodiment of the present invention and is not used to limit the present invention. For those skilled in the art, various changes and modifications can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A thermal interface material with a local temperature monitoring function, characterized in that: Specifically, it is a polypyrrole thermal interface material, and the raw materials are iron salts, fiber-forming agents, surfactants and organic solvents.

2. The preparation method of a thermal interface material with a local temperature monitoring function according to claim 1, characterized in that: The specific steps of the preparation method are as follows: S1. Preparation of polypyrrole fibers: Add iron salts and fiber-forming agents to ethanol and N,N-dimethylformamide to prepare a spinning solution. Load the solution into a plastic syringe and collect it at a fixed distance under a constant voltage, and perform electrospinning at a constant flow rate. Anneal the electrospun nanofibers in air to obtain hollow magnetic iron oxide nanofibers; Disperse the hollow magnetic iron oxide nanofibers as a sacrificial template into deionized water containing surfactants, and vigorously stir at room temperature to obtain a suspension; add pyrrole monomers to the suspension and further stir vigorously; add oxidants and hydrochloric acid to deionized water, mix and then drop it into the system, and continuously stir gently in a water bath to start the polymerization process. After stirring, the color of the solution turns black, the reaction is completed, the product is centrifuged, washed with deionized water, and dried in vacuum to obtain polypyrrole fibers; S2. Preparation of polypyrrole thermal interface material: Add polypyrrole fibers to an organic solvent, stir and mix, then pour the suspension into a polystyrene Petri dish with a diameter of 30 mm to form a liquid with a height of about 10 mm, and immediately move it to the magnetic field generated by two neodymium iron boron magnets. When all the fibers settle to the bottom, place the magnet and the dish on a vibrating platform and vibrate horizontally to make the polypyrrole fibers vertically arranged and stacked. Freeze-dry under the magnetic field to remove the solvent, and heat-treat under inert gas protection; Mix the a and b components of the addition-type silicone gel evenly to prepare a matrix solution, pour it into the vertical polypyrrole fiber array, and remove the bubbles and cure it in a vacuum drying oven to obtain a thermal interface material based on the vertical polypyrrole fiber array.

3. A method for preparing a thermal interface material with a local temperature monitoring function according to claim 2, characterized in that: In S1, the iron salts are one or more combinations of ferric chloride hexahydrate, ferric nitrate hexahydrate, ferrous sulfate and / or iron acetylacetonate, the fiber-forming agents are one or more combinations of polyvinylpyrrolidone, polyethylene glycol, polyvinyl alcohol and / or polyacrylonitrile, and the surfactants are one or more combinations of sodium dodecyl sulfate, sodium dodecylbenzenesulfonate and / or cetyltrimethylammonium bromide.

4. The preparation method of a thermal interface material with a local temperature monitoring function according to claim 2, characterized in that: In S1, the molar ratio of iron salts, fiber-forming agents, ethanol and N,N-dimethylformamide is 1:35:13.7:2.6; the molar ratio of hollow magnetic iron oxide nanofibers to surfactants and deionized water is 0.3 - 0.8:1000 - 2000:2780 - 2780; the molar ratio of oxidants, hydrochloric acid and deionized water is 5 - 25:3 - 6:69.5 - 139.

5. The preparation method of a thermal interface material with a local temperature monitoring function according to claim 2, characterized in that: In S1, electrospinning is carried out at a voltage of 25 - 30 kV and a collection distance of 20 - 25 cm at a flow rate of 0.5 - 1.0 mL / h. -1 The electrospun nanofibers are annealed in air at 500 °C for 2 h to obtain 0.3 - 0.8 mmol of hollow magnetic iron oxide nanofibers.

6. The preparation method of a thermal interface material with a local temperature monitoring function according to claim 2, characterized in that: In S1, stir vigorously at room temperature for 11 - 12 h to obtain a suspension; add pyrrole monomers to the suspension and stir vigorously for another 10 h; start the polymerization process, after stirring for 24 h; dry in vacuum at 60 °C for 24 h to obtain polypyrrole fibers.

7. A method for preparing a thermal interface material with a local temperature monitoring function according to claim 2, characterized in that: In S2, the organic solvents are one or more combinations of polyvinyl alcohol, N-methylpyrrolidone and / or N,N-dimethylformamide.

8. The preparation method of a thermal interface material with a local temperature monitoring function according to claim 2, characterized in that: In the above S2, the molar ratio of the organic solvent to the polypyrrole fiber is 4.6 - 11.8:1, and the concentration of the polypyrrole fiber in the organic solvent varies within the range of 10 - 15 wt%; the inert gas is a mixture of helium and argon, and the ratio is 1:

19.

9. A method for preparing a thermal interface material with a local temperature monitoring function according to claim 8, characterized in that: In the above S2, polypyrrole fibers are added to the organic solvent, stirred for 30 min, subjected to horizontal vibration at a frequency of 25 - 30 Hz and an amplitude of 0.5 - 0.6 mm for 1 - 3 min, freeze-dried for 48 - 50 hours to remove the solvent, and the freeze-dried sample is heat-treated at 180 °C under a 5% mixture of helium and argon for 3 hours.

10. The preparation method of a thermal interface material with a local temperature monitoring function according to claim 2, characterized in that: In the above S2, the addition-type silicone gel a and b components are mixed evenly according to the ratio of 1:1 to prepare a matrix solution; it is cured at 140 °C for 6 h.

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