A thermal interface conductive gel with temperature responsiveness and self-filling property, and a preparation method and application thereof

Abstract

The present application belongs to the technical field of functional materials, and specifically comprises a thermal interface heat-conducting gel with temperature responsiveness and self-filling property, and a preparation method and application thereof. The preparation method comprises the following steps: S1, fully mixing a double-hydroxyl single-terminated monomer, a single-hydroxyl double-terminated monomer and a diisocyanate to obtain a heat-conducting gel prepolymer solution; S2, mixing micro heat-conducting particles, nano heat-conducting particles, a solvent and a fluorosilane in a certain proportion, modifying the micro heat-conducting particles and the nano heat-conducting particles with the fluorosilane, centrifuging, collecting the precipitate, washing with deionized water, and obtaining micro-nano heat-conducting particles; S3, mixing the heat-conducting gel prepolymer solution and the micro-nano heat-conducting particles in a certain proportion, mechanically stirring, adding a tin catalyst, mixing, and ultrasonic defoaming to obtain a heat-conducting gel micro-nano composite; and S4, performing a gradient temperature rise on the heat-conducting gel micro-nano composite to perform an urethane reaction, and obtaining a thermal interface heat-conducting gel.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology, specifically including a thermally conductive gel with temperature responsiveness and self-filling properties, its preparation method, and its application. Background Technology

[0002] Overheating has become a core constraint on the development of microelectronic devices, directly affecting the reliability, operational performance, and miniaturization of devices such as computers and light-emitting diodes (LEDs). As device power density continues to increase and size shrinks, the overheating problem becomes increasingly severe. Therefore, developing efficient cooling methods has become an urgent technical challenge. Currently, the most widely used cooling method utilizes a heat sink in direct thermal contact with the heat source to transfer heat to the surrounding environment for cooling. However, poor contact between the heat source and the heat sink can severely hinder heat transfer efficiency, ultimately preventing the heat sink from achieving its designed cooling effect.

[0003] Thermal interface materials are a core class of thermally conductive materials, requiring both high thermal conductivity and good adhesion to rough surfaces and micro-gaps. They can create thermal bridges between adjacent heat sources and heat sinks, achieving efficient heat conduction and dissipation—a crucial function for the performance and lifespan of electronic devices. The thermal conductivity of thermal interface materials is primarily determined by two factors: their inherent thermal conductivity and contact thermal resistance. In recent years, research in academia and industry has focused on improving thermal conductivity. Strategies such as filler surface modification, low-dimensional filler vertical orientation, and constructing three-dimensional filler networks have effectively enhanced the out-of-plane thermal conductivity of materials. However, current research on improving contact thermal resistance remains relatively limited. The magnitude of contact thermal resistance mainly depends on the wettability and flowability of the thermal interface material at the interface. Especially when the material thickness is less than 200 micrometers, contact thermal resistance can account for more than 40% of the total thermal resistance. Therefore, developing thermal interface materials with low contact thermal resistance has become a critical area requiring urgent attention.

[0004] Currently, most research focuses on reducing interfacial thermal resistance through material phase transitions. Surf. Interfaces 2024,55, 105406.) Appl. Therm. Eng. 2023, 230, 120807.) Small Struct. , 6:2500139.) ( Int. J. Therm. Sci. (2020, 152, 106293.). However, these studies generally lack reversible adhesion capabilities and cannot meet the fixation requirements of heat sinks.

[0005] Meanwhile, current thermal greases face many unavoidable drawbacks in practical applications. For example, when exposed to high temperatures for extended periods, they are prone to drying out and oil seepage, leading to a rapid decline in thermal conductivity and a lifespan typically ranging from a few months to a year. This fails to meet the long-term stable operation requirements of electronic equipment. For instance, Shin-Etsu X-23-7762, Shin-Etsu X-23-7783D, and Shin-Etsu X-23-7868-2D exhibit a volatilization rate exceeding 2.4 vol% after heating at 150°C for 24 hours. If the thermal grease lacks insulating properties, oil seepage can also contaminate electronic components, increasing the risk of short circuits and malfunctions, and posing safety hazards to equipment operation.

[0006] In addition, electronic devices often encounter complex conditions such as vibration and drops during assembly, transportation and actual use. These conditions place higher demands on thermal interface materials, namely, they need to have good impact resistance and stable interface firmness. The quality of these two properties directly determines whether the heat dissipation system can maintain a stable heat dissipation effect in the long term. Summary of the Invention

[0007] In view of the above-mentioned problems in the prior art, the first objective of the present invention is to provide a method for preparing a thermally conductive gel with temperature responsiveness and self-filling properties.

[0008] A second objective of this invention is to provide a thermally conductive gel with temperature responsiveness and self-filling properties prepared by the preparation method described above.

[0009] A third objective of this invention is to provide an application of the temperature-responsive and self-filling thermal interface thermal conductive gel described above in the preparation of thermal conductive materials for microelectronic devices.

[0010] It should be noted that temperature responsiveness and self-filling properties are the two main characteristics of the thermal interface conductive gel in this invention. Temperature responsiveness refers to the temperature-triggered phase change capability of the thermal interface conductive gel. In practical use, the thermal interface conductive gel placed between the heat source and the heat sink will undergo dissociation of its internal hydrogen bond clusters under the influence of absorbed heat, causing the thermal interface conductive gel to change from a solid to a liquid state. When the heat source temperature drops to its initial state, the thermal interface conductive gel will revert to a solid state. This has the advantage that when the device is operating, the thermal interface conductive gel can fully spread across the interface, reducing air thermal resistance, while when the device is not in operation, it exhibits excellent interface impact resistance. Self-filling properties refer to the ability of the thermal interface conductive gel to fully spread across the interface after being heated to a liquid state, effectively filling the air gaps in the interface, thereby reducing air thermal resistance and contact thermal resistance. Therefore, the thermal interface conductive gel provided by this invention can not only achieve efficient wetting of the thermal interface and full filling of air gaps, but also has excellent interface impact resistance and strong interface adhesion. It can specifically solve the core performance shortcomings of current microelectronic device heat dissipation systems in terms of thermal interface materials in terms of thermal conductivity, contact thermal resistance, and structural stability. By achieving synergistic optimization of high thermal conductivity, low contact thermal resistance and strong impact resistance, it ensures the long-term reliable operation of high-power, miniaturized microelectronic devices, and thus provides key material support for device performance improvement and further miniaturization.

[0011] To achieve the first objective mentioned above, the technical solution adopted by the present invention includes:

[0012] This invention discloses a method for preparing a thermally conductive gel with temperature responsiveness and self-filling properties, comprising the following steps:

[0013] S1. Thoroughly mix the dihydroxy single-terminated monomer, the single-hydroxy double-terminated monomer, and the diisocyanate to obtain the thermally conductive gel prepolymer solution;

[0014] S2. Mix micron-sized thermally conductive particles, nano-sized thermally conductive particles, solvent and fluorosilane in a certain proportion, modify the micron-sized thermally conductive particles and nano-sized thermally conductive particles with fluorosilane, centrifuge, collect the precipitate, wash with deionized water to obtain micro-nano thermally conductive particles.

[0015] S3. Mix the thermally conductive gel prepolymer and micro / nano thermally conductive particles in a certain proportion, stir mechanically, add a tin catalyst, mix, and defoam by ultrasonication to obtain the thermally conductive gel micro / nano composite.

[0016] S4. The thermally conductive gel micro-nano composite is subjected to gradient heating to carry out an urethane reaction, thereby obtaining a thermally conductive gel at the thermal interface.

[0017] The molecular weight of the dihydroxy single-terminated monomer is 1000~8000, and it is selected from the structure shown in Formula I below:

[0018] I;

[0019] R1 is selected from , , , One of them;

[0020] n1 is an integer from 10 to 40, n2 and n5 are integers from 10 to 50, and n3 and n4 are integers from 5 to 20.

[0021] The monohydroxy double-terminated monomer has a molecular weight of 1000-8000 and is selected from the structure shown in Formula II below:

[0022] II;

[0023] R2 is selected from , , , One of them;

[0024] n6, n7, n9, and n10 are integers from 5 to 20, and n8 and n11 are integers from 10 to 50.

[0025] The thermally conductive gel with temperature responsiveness and self-filling properties provided by this invention is composed of a thermally conductive gel prepolymer liquid urethane reaction product and micro / nano thermally conductive particles. Hydrogen bonds can form between the urethane bonds formed by the urethane reaction of the dihydroxy mono-terminated monomers and monohydroxy di-terminated monomers contained in the thermally conductive gel prepolymer liquid. These hydrogen bonds aggregate to form hydrogen-bonded clusters, which can form strong adhesion to the interface. Simultaneously, the dihydroxy mono-terminated hydrophobic segments align outwards from the hydrogen-bonded clusters, resulting in low surface energy and wetting. The hydrogen-bonded clusters and the externally wrapped hydrophobic segments together form a microphase-separated nanocluster. The monohydroxy di-terminated monomers connect the individual nanoclusters through urethane bonds, enhancing the gel's cohesive strength. Micron-sized particles form continuous thermal conductive pathways, and nanoscale particles can fill the gaps between micron-sized particles, achieving a denser packing, avoiding point connections between particles, and eliminating thermal resistance.

[0026] Furthermore, the molar ratio of the dihydroxy mono-terminated monomer to the monohydroxy di-terminated monomer is 1:0.1 to 1; exemplarily, the molar ratio of the dihydroxy mono-terminated monomer to the monohydroxy di-terminated monomer can be 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, etc. By controlling the molar ratio of the dihydroxy mono-terminated monomer to the monohydroxy di-terminated monomer, the flowability of the crosslinked gel can be affected. Within the above range, the content can be kept moderate, so that the gel is neither too thin to form properly nor too thick to flow easily. To facilitate the weighing of raw materials, the following also provides the mass ratio control of the dihydroxy mono-terminated monomer and the monohydroxy di-terminated monomer, which is designed based on the appropriate molar ratio relationship and molecular weight difference between the two monomers.

[0027] Furthermore, the mass ratio of the dihydroxy mono-terminated monomer to the monohydroxy di-terminated monomer is 100:25~100; exemplaryly, the mass ratio of the dihydroxy mono-terminated monomer to the monohydroxy di-terminated monomer can be 100:25, 100:30, 100:35, 100:40, 100:45, 100:50, 100:55, 100:60, 100:65, 100:70, 100:75, 100:80, 100:85, 100:90, 100:95, 100:100, etc. By adjusting the mass ratio of the dihydroxy mono-terminated monomer to the monohydroxy di-terminated monomer, the degree of hydrogen-bonded cluster phase separation can be controlled. The more dihydroxy single-terminated monomer components there are, the closer the urethane bonds and hydrogen bonds become, resulting in higher energy, greater phase separation of hydrogen-bonded clusters, stronger adhesion between hydrogen-bonded clusters and the interface, and stronger energy dissipation capacity of hydrogen-bonded clusters, thus enhancing resistance to external impacts. Conversely, the more single-hydroxy double-terminated monomer components there are, the higher the cohesive strength of the thermally conductive gel.

[0028] Furthermore, the dihydroxy single-terminated monomer is selected from the following structures:

[0029] Dihydroxy-terminated perfluoropolyether, where n is an integer from 10 to 40.

[0030] Furthermore, the monohydroxy dual-terminated monomer is selected from the following structures:

[0031] Single-hydroxyl double-terminated perfluoropolyether, where m and n are integers from 5 to 20.

[0032] Furthermore, the diisocyanate, as a crosslinking agent of the system, is selected from one of 4,4′-methylenebis(cyclohexyl isocyanate), 1,3-bis(1-isocyano-1-methylethyl)benzene, isophorone diisocyanate, hexamethylene diisocyanate, and 1,3-bis(isocyanomethyl)cyclohexane.

[0033] Through the synergistic combination of dihydroxy mono-terminated monomers, monohydroxy di-terminated monomers, and diisocyanate, the system can be provided with functions such as strong interfacial adhesion, electrical insulation, resistance to external impact, high thermal conductivity, and low contact thermal resistance. In one specific embodiment, the molar ratio of the sum of the dihydroxy mono-terminated monomers and monohydroxy di-terminated monomers to the molar ratio of diisocyanate is maintained at 1:1-1.05.

[0034] Furthermore, the mass ratio of the dihydroxy mono-terminated monomer, the monohydroxy di-terminated monomer, and the diisocyanate is 100:25~100:6~12.

[0035] Furthermore, the micron-sized thermally conductive particles are selected from one or more of alumina particles, magnesium oxide particles, boron nitride microspheres, zinc oxide particles, silicon carbide particles, and aluminum nitride particles.

[0036] Furthermore, the nano-thermal conductive particles are selected from one or more of alumina particles, zinc oxide particles, magnesium oxide particles, silicon carbide particles, and aluminum nitride particles.

[0037] This invention employs a combination of micron-sized and nano-sized thermally conductive particles, which can effectively achieve bridging between particles and realize more efficient heat conduction.

[0038] Furthermore, the solvent is selected from one or more of n-heptane, n-hexane, cyclohexane, and toluene.

[0039] Furthermore, the fluorosilane is selected from one or more of perfluorooctyltriethoxysilane, 1H,1H,2H,2H-perfluorooctyltrimethoxysilane, 3-aminopropyltriethoxysilane, and 3-(methacryloyloxy)propyltrimethoxysilane.

[0040] Furthermore, the mass ratio of the micron-sized thermally conductive particles, the nano-sized thermally conductive particles, the solvent, and the fluorosilane is 10:2 to 10:50:0.2.

[0041] Furthermore, in step S2, fluorosilane can modify the micron-sized and nano-sized thermally conductive particles, allowing the modified particles to mix better with the thermally conductive gel prepolymer without agglomeration. In one specific embodiment, the modification time is 3-6 hours.

[0042] Furthermore, in step S3, the mechanical stirring time is 2~6 hours.

[0043] Furthermore, the mass ratio of the thermally conductive gel prepolymer to the micro / nano thermally conductive particles is 10:2-10; for example, the mass ratio of the thermally conductive gel prepolymer to the micro / nano thermally conductive particles can be 10:2, 10:3, 10:4, 10:5, 10:6, 10:7, 10:8, 10:9, 10:10, etc.

[0044] Furthermore, the tin-based catalyst is selected from one of dibutyltin dilaurate, dibutyltin diacetate, stannous octoate, etc. The amount of the tin-based catalyst added is 0.4-0.6 wt% of the mass of the thermally conductive gel prepolymer.

[0045] Furthermore, in step S4, the gradient heating involves first holding the temperature at 50-70℃ for 1.5-2.5 hours, and then raising the temperature to 75-90℃ and holding it for 10-15 hours.

[0046] To achieve the second objective mentioned above, the technical solution adopted by the present invention includes:

[0047] This invention discloses a thermally conductive gel with temperature responsiveness and self-filling properties, which is prepared by the preparation method described above.

[0048] To achieve the third objective mentioned above, the technical solution adopted by the present invention includes:

[0049] This invention discloses the application of the temperature-responsive and self-filling thermal interface thermal conductive gel described above in the preparation of thermal conductive materials for microelectronic devices.

[0050] Beneficial effects of this invention:

[0051] This invention's thermally conductive gel achieves a reversible phase transition through a temperature-triggered dissociation and recombination mechanism of phase-separated hydrogen-bonded clusters. During device operation, the gel liquefies upon heating, fully spreading and wetting the interface between the heat source and the heat sink, efficiently filling microscopic gaps and air pores, reducing contact thermal resistance to an extremely low level. When the device is shut down, it reverts to a solid state, exhibiting both excellent impact resistance and interface stability, thus resolving the core contradiction of traditional thermal interface materials where high fluidity and structural stability are mutually exclusive. A composite system of micron-sized and nano-sized thermally conductive particles is employed. The micron-sized particles establish a continuous thermal conduction pathway, while the nano-sized particles fill the gaps between them, achieving tight bridging and dense packing between particles, avoiding thermal resistance dead zones caused by single-size particles. Simultaneously, fluorosilane modification enhances the compatibility between the particles and the gel matrix, preventing particle agglomeration and further strengthening thermal conductivity, giving the gel the dual advantages of high thermal conductivity and low interfacial contact thermal resistance.

[0052] The thermal interface conductive gel system constructed through chemical modification and cross-linking reactions has a dense structure that is not easily decomposed. The product is free of oil seepage, volatiles, and drying out, solving the problem of short service life of traditional thermal greases and other materials. The entire preparation process does not require extreme reaction conditions such as high pressure and high temperature. The equipment used for mechanical stirring, centrifugation, and gradient heating are all conventional equipment in the chemical industry, resulting in low investment costs and easy upgrading of existing production lines, thus lowering the industrialization threshold. The thermally conductive particles, solvents, and fluorosilanes are all made from readily available industrial-grade raw materials, and multiple material replacements are supported. The selection of raw materials can be flexibly adjusted according to different application scenarios, demonstrating strong adaptability.

[0053] The thermal interface conductive gel exhibits outstanding performance in several key aspects, achieving an adhesion strength of 120 kPa at the interface and withstanding 400 J·m under impact. -1 The material effectively absorbs energy and mitigates the impact of vibration, drops, and other operating conditions on interface stability. It also possesses electrical breakdown resistance, with a breakdown strength exceeding 25 kV / mm, meeting the electrical safety requirements of electronic equipment. Its thermal conductivity remains consistently at 5.8 W·m. -1 ·K -1 The interfacial contact thermal resistance is less than 0.15 cm. 2 ·K·W -1 This can effectively reduce the thermal conduction barrier between the heat source and the heat sink. In actual heat dissipation tests, when the heat flux density is 2000 W / m³, 2 When thermal interface gel was added, the temperature of the thermal interface only rose to 75°C, while that of commercial thermal grease reached 85°C. Compared to traditional silicone grease, thermal interface gel achieved a cooling effect of over 11°C. Furthermore, after 100 temperature cycles from 25°C to 85°C, the thermal conductivity of thermal interface gel remained stable, demonstrating excellent thermal cycling reliability. Attached Figure Description

[0054] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0055] Figure 1 This is a schematic diagram of the molecular structure and synthesis process of the thermal interface thermally conductive gel prepared in Example 1.

[0056] Figure 2 A schematic diagram of the temperature response of the thermal interface thermally conductive gel prepared in Example 1.

[0057] Figure 3 Interfacial wettability and comparison of the thermal interface conductive gel prepared in Example 1.

[0058] Figure 4 This is a schematic diagram of the mechanical damping of the thermal interface thermally conductive gel prepared in Example 1.

[0059] Figure 5 Electrothermal heating test of the thermal interface thermally conductive gel prepared in Example 1.

[0060] Figure 6 Infrared testing of the thermal interface thermally conductive gel prepared in Example 1.

[0061] Figure 7 Temperature cycling test of the thermal interface thermally conductive gel prepared in Example 1. Detailed Implementation

[0062] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further clarifies the invention. It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0063] In addition, unless otherwise specified, all raw materials used in this invention can be obtained commercially available. Any range described in this invention includes the end value and any value between the end values, as well as any subrange formed by the end value or any value between the end values.

[0064] Example 1

[0065] This example provides a method for preparing a temperature-responsive thermal interface thermally conductive gel, including the following steps:

[0066] S1. Mix dihydroxy single-terminated perfluoropolyether (molecular weight 4000), single-hydroxy double-terminated perfluoropolyether (molecular weight 4000), and isophorone diisocyanate in a mass ratio of 100:25:7 to prepare a thermally conductive gel prepolymer.

[0067] The structure of the dihydroxy-terminated perfluoropolyether is as follows:

[0068] ;

[0069] The structure of the single-hydroxyl-terminated double-ended perfluoropolyether is as follows:

[0070] ;

[0071] S2. Micron-sized alumina particles, nano-sized alumina particles, n-hexane, and 1H,1H,2H,2H-perfluorooctyltrimethoxysilane were sheared and mixed for 6 hours at a mass ratio of 10:4:50:0.2 to modify the micron-sized and nano-sized alumina particles. The suspension was centrifuged at 8000 rpm for 10 minutes to collect the precipitate, which was washed twice with deionized water to obtain micro / nano thermally conductive particles.

[0072] S3. The thermally conductive gel prepolymer and micro / nano thermally conductive particles are mechanically stirred at a mass ratio of 10:10 for 6 hours. Then, 0.5% of the mass of dibutyltin dilaurate catalyst is added to the thermally conductive gel prepolymer, stirred for 10 minutes, and ultrasonically defoamed for 10 minutes to prepare the thermally conductive gel micro / nano composite.

[0073] S4. The thermally conductive gel micro-nano composite is first heated at 60℃ for 2 hours, and then heated at 80℃ for 12 hours to complete the urethane reaction and obtain the thermal interface thermally conductive gel.

[0074] Figure 1This is a schematic diagram of the molecular structure and synthesis process of the thermally conductive gel prepared in Example 1. The dihydroxy mono-terminated monomers and monohydroxy di-terminated monomers contained in the thermally conductive gel prepolymer undergo urethane reaction, forming carbamate bonds that can bond with each other. Carbamate bonds formed by dihydroxy mono-terminated monomers with closely spaced hydroxyl groups aggregate to form nano-hydrogen-bonded clusters. Simultaneously, the hydrophobic segments of the dihydroxy mono-terminated monomers align outwards from the hydrogen-bonded clusters, forming fluorinated side chains that encapsulate the nano-hydrogen-bonded clusters. The hydrogen-bonded clusters and the externally encapsulated hydrophobic segments together form a microphase-separated nano-hydrogen-bonded cluster. The monohydroxy di-terminated monomers connect the individual nano-clusters through carbamate bonds to form the gel system. Figure 2 This is a schematic diagram illustrating the temperature response of the thermally conductive gel prepared in Example 1. The gel can transform into a low-viscosity flow state in response to temperature, effectively filling the air gaps between hot surfaces and achieving extremely low contact thermal resistance at the interface. Simultaneously, its internal micro / nano thermally conductive particles can bridge each other, optimizing the heat conduction path to enhance overall thermal conductivity.

[0075] The thermal diffusivity of the gel was calculated using a laser thermal conductivity analyzer, and the thermal conductivity of the gel was then derived. The thermal resistance of the gel was calculated using steady-state heat flow technology (ASTM D5470). The adhesion effect of the gel was tested using a temperature control device and a mechanical testing machine. The material's resistance to mechanical impact and energy absorption effect were obtained by calculating gravitational potential energy through an iron ball impact test. This thermally conductive gel can achieve a thickness of 0.15 cm. 2 KW -1 The interfacial thermal resistance and 5.8 W / m -1 K -1 The thermal conductivity is high. Simultaneously, the thermally conductive gel achieves an adhesion strength of 120 kPa and 132 J·m at the interface. -2 The adhesion work is significant. The microphase-separated hydrogen-bonded clusters within the thermally conductive gel possess an energy-absorbing damping effect, capable of absorbing energy and protecting the underlying substrate during impact, with a maximum energy absorption capacity of 398 J·m. -1 Meanwhile, its electrical breakdown resistance can reach 25 kV / mm.

[0076] Figure 3 The microstructure of the interface between the commercial thermal pad and the thermal interface gel of Example 1, when implemented on electronic devices, shows that the commercial thermal pad still has a significant air gap with the thermal interface after preheating, failing to eliminate the contact thermal resistance between the interfaces. In contrast, Example 1 can completely adhere to the thermal interface after preheating, effectively eliminating the air thermal resistance between the interfaces.

[0077] Figure 4This diagram illustrates the resistance to external mechanical impact testing of the thermal interface conductive gel in Example 1. The thermal interface conductive gel was struck with a wooden hammer, and the gel exhibited a significant rebound after impact. Simultaneously, when the thermal interface conductive gel was applied to a glass substrate, the glass substrate beneath the gel remained intact after being struck with the hammer. Conversely, the glass substrate without the conductive gel showed signs of cracking.

[0078] Example 2

[0079] This example provides a method for preparing a temperature-responsive thermal interface thermally conductive gel, including the following steps:

[0080] S1. Mix dihydroxy mono-terminated perfluoropolyether (molecular weight 4000), monohydroxy di-terminated perfluoropolyether (molecular weight 4000), and isophorone diisocyanate in a mass ratio of 100:50:8.5 to prepare a thermally conductive gel prepolymer.

[0081] The structures of the dihydroxy single-terminated perfluoropolyether and the monohydroxy double-terminated perfluoropolyether are the same as in Example 1;

[0082] S2. Micron-sized alumina particles, nano-sized alumina particles, n-hexane, and 1H,1H,2H,2H-perfluorooctyltrimethoxysilane were sheared and mixed for 6 hours at a mass ratio of 10:4:50:0.2 to modify the micron-sized and nano-sized alumina particles. The suspension was centrifuged at 8000 rpm for 10 minutes to collect the precipitate, which was washed twice with deionized water to obtain micro / nano thermally conductive particles.

[0083] S3. The thermally conductive gel prepolymer and micro / nano thermally conductive particles are mechanically stirred at a mass ratio of 10:10 for 6 hours. Then, 0.5% of the mass of dibutyltin dilaurate catalyst is added to the thermally conductive gel prepolymer, stirred for 10 minutes, and ultrasonically defoamed for 10 minutes to prepare the thermally conductive gel micro / nano composite.

[0084] S4. The thermally conductive gel micro-nano composite is first heated at 60℃ for 2 hours, and then heated at 80℃ for 12 hours to complete the urethane reaction and obtain the thermal interface thermally conductive gel.

[0085] The thermally conductive gel has a diameter of 0.36 cm. 2 KW -1 The interfacial thermal resistance and 5.7 W / m -1 K -1 The thermal conductivity is [value missing]. Simultaneously, the thermally conductive gel exhibits an adhesion strength of 102 kPa and 95.5 J·m at the interface. -2 The adhesion work is significant. The microphase-separated hydrogen-bonded clusters within the thermally conductive gel possess an energy-absorbing damping effect, capable of absorbing energy and protecting the underlying substrate during impact, with a maximum energy absorption capacity of 130 J·m⁻¹. -1 Meanwhile, its electrical breakdown resistance can reach 24.2 kV / mm.

[0086] Example 3

[0087] This example provides a method for preparing a temperature-responsive thermal interface thermally conductive gel, including the following steps:

[0088] S1. Mix dihydroxy single-terminated perfluoropolyether (molecular weight 4000), single-hydroxy double-terminated perfluoropolyether (molecular weight 4000), and isophorone diisocyanate in a mass ratio of 100:25:7 to prepare a thermally conductive gel prepolymer.

[0089] The structures of the dihydroxy single-terminated perfluoropolyether and the monohydroxy double-terminated perfluoropolyether are the same as in Example 1;

[0090] S2. Micron-sized alumina particles, nano-sized alumina particles, n-hexane, and 1H,1H,2H,2H-perfluorooctyltrimethoxysilane were sheared and mixed for 6 hours at a mass ratio of 10:2:50:0.2 to modify the micron-sized and nano-sized alumina particles. The suspension was centrifuged at 8000 rpm for 10 minutes to collect the precipitate, which was washed twice with deionized water to obtain micro / nano thermally conductive particles.

[0091] S3. The thermally conductive gel prepolymer and micro / nano thermally conductive particles are mechanically stirred at a mass ratio of 10:10 for 6 hours. Then, 0.5% of the mass of dibutyltin dilaurate catalyst is added to the thermally conductive gel prepolymer, stirred for 10 minutes, and ultrasonically defoamed for 10 minutes to prepare the thermally conductive gel micro / nano composite.

[0092] S4. The thermally conductive gel micro-nano composite is first heated at 60℃ for 2 hours, and then heated at 80℃ for 12 hours to complete the urethane reaction and obtain the thermal interface thermally conductive gel.

[0093] The thermally conductive gel has a thickness of 0.15 cm. 2 KW -1 The interfacial thermal resistance and 4.2 W / m -1 K -1 The thermal conductivity is [value missing]. Simultaneously, the thermally conductive gel achieves an adhesion strength of 118.5 kPa and 130.4 J·m at the interface. -2 The adhesion work. Hydrogen-bonded clusters possess energy-absorbing damping properties, capable of absorbing energy and protecting the underlying substrate during impact, with a maximum energy absorption capacity of 390 J·m. -1 Its electrical breakdown resistance can reach 24.8 kV / mm.

[0094] Example 4

[0095] This example provides a method for preparing a temperature-responsive thermal interface thermally conductive gel, including the following steps:

[0096] S1. Mix dihydroxy single-terminated perfluoropolyether (molecular weight 4000), single-hydroxy double-terminated perfluoropolyether (molecular weight 4000), and isophorone diisocyanate in a mass ratio of 100:25:7 to prepare a thermally conductive gel prepolymer.

[0097] The structures of the dihydroxy single-terminated perfluoropolyether and the monohydroxy double-terminated perfluoropolyether are the same as in Example 1;

[0098] S2. Micron-sized alumina particles, nano-sized alumina particles, n-hexane, and 1H,1H,2H,2H-perfluorooctyltrimethoxysilane were sheared and mixed for 6 hours at a mass ratio of 10:6:50:0.2 to modify the micron-sized and nano-sized alumina particles. The suspension was centrifuged at 8000 rpm for 10 minutes to collect the precipitate, which was then washed twice with deionized water to obtain micro / nano thermally conductive particles.

[0099] S3. The thermally conductive gel prepolymer and micro / nano thermally conductive particles are mechanically stirred at a mass ratio of 10:10 for 6 hours. Then, 0.5% of the mass of dibutyltin dilaurate catalyst is added to the thermally conductive gel prepolymer, stirred for 10 minutes, and ultrasonically defoamed for 10 minutes to prepare the thermally conductive gel micro / nano composite.

[0100] S4. The thermally conductive gel micro-nano composite is first heated at 60℃ for 2 hours, and then heated at 80℃ for 12 hours to complete the urethane reaction and obtain the thermal interface thermally conductive gel.

[0101] The thermally conductive gel has a density of 0.19 cm. 2 KW -1 The interfacial thermal resistance and 4.7 W / m -1 K -1 The thermal conductivity is [value missing]. Simultaneously, the thermally conductive gel achieves an adhesion strength of 114 kPa and 128.5 J·m at the interface. -2 The adhesion work. Hydrogen-bonded clusters possess energy-absorbing damping properties, capable of absorbing energy and protecting the underlying substrate during impact, with a maximum energy absorption capacity of 390 J·m. -1 Its electrical breakdown resistance can reach 24.9 kV / mm.

[0102] Comparative Example 1

[0103] This example provides a method for preparing a temperature-responsive thermal interface thermally conductive gel, including the following steps:

[0104] S1. Mix dihydroxy single-terminated perfluoropolyether (molecular weight 4000), single-hydroxy double-terminated perfluoropolyether (molecular weight 4000), and isophorone diisocyanate in a mass ratio of 100:25:7 to prepare a thermally conductive gel prepolymer.

[0105] The structures of the dihydroxy single-terminated perfluoropolyether and the monohydroxy double-terminated perfluoropolyether are the same as in Example 1;

[0106] S2. Micron-sized alumina particles, nano-sized alumina particles, n-hexane, and fluorosilane were sheared and mixed at a mass ratio of 10:4:50:0.2 for 6 hours to modify the micron-sized and nano-sized alumina particles. The suspension was centrifuged at 8000 rpm for 10 minutes to collect the precipitate, which was then washed twice with deionized water to obtain micro / nano thermally conductive particles.

[0107] S3. The thermally conductive gel prepolymer and micro / nano thermally conductive particles are mechanically stirred at a mass ratio of 10:2 for 6 hours. 0.5% of the mass of dibutyltin dilaurate catalyst of the thermally conductive gel prepolymer is added, stirred for 10 minutes, and ultrasonically defoamed for 10 minutes to prepare the thermally conductive gel micro / nano composite.

[0108] S4. The thermally conductive gel micro-nano composite is first heated at 60℃ for 2 hours, and then heated at 80℃ for 12 hours to complete the urethane reaction and obtain the thermal interface thermally conductive gel.

[0109] Due to the extremely low content of thermally conductive particles, the particles are too widely spaced within the gel and cannot easily contact each other, making it impossible to construct a continuous thermally conductive pathway within the matrix. Heat can only be transferred through the matrix, which has extremely low thermal conductivity, significantly limiting the thermal conductivity efficiency. This thermally conductive gel has a thermal conductivity of only 1.1 W / m². -1 K -1 The thermal conductivity of this thermally conductive gel is 0.15 cm⁻¹. 2 KW -1 The interfacial thermal resistance is low, while the thermally conductive gel achieves an adhesion capacity of 120.2 kPa and 131.2 J·m at the interface. -2 The adhesion work. Hydrogen-bonded clusters possess energy-absorbing damping properties, capable of absorbing energy and protecting the underlying substrate during impact, with a maximum energy absorption capacity of 380 J·m. -1 Its electrical breakdown resistance can reach 24.5 kV / mm.

[0110] Comparative Example 2

[0111] This example provides a method for preparing a thermally conductive gel with a thermal interface, including the following steps:

[0112] S1. Mix dihydroxy single-terminated perfluoropolyether (molecular weight 4000), single-hydroxy double-terminated perfluoropolyether (molecular weight 4000), and isophorone diisocyanate in a mass ratio of 100:25:7 to prepare a thermally conductive gel prepolymer.

[0113] The structures of the dihydroxy single-terminated perfluoropolyether and the monohydroxy double-terminated perfluoropolyether are the same as in Example 1;

[0114] S2. Micron-sized alumina particles, n-hexane, and 1H,1H,2H,2H-perfluorooctyltrimethoxysilane were sheared and mixed for 6 hours at a mass ratio of 10:50:0.2. The suspension was centrifuged at 8000 rpm for 10 minutes to collect the precipitate, which was then washed twice with deionized water to obtain thermally conductive particles.

[0115] S3. The thermally conductive gel prepolymer and thermally conductive particles are mechanically stirred at a mass ratio of 10:10 for 6 hours. 0.5% of the mass of the thermally conductive gel prepolymer and dibutyltin dilaurate catalyst are added. The mixture is stirred for 10 minutes and ultrasonically defoamed for 10 minutes to prepare the thermally conductive gel composite.

[0116] S4. The thermally conductive gel composite is first heated at 60℃ for 2 hours, and then heated at 80℃ for 12 hours to complete the urethane reaction and obtain the thermal interface thermally conductive gel.

[0117] Because this thermally conductive gel lacks the composite structure of micro / nano thermally conductive particles, the micron-sized particles easily form point contacts, reducing thermal conductivity. The thermally conductive pathways formed by particle-filled bridging are significantly reduced, resulting in a minimum thermal conductivity of 0.15 cm⁻¹. 2 KW -1 The interfacial thermal resistance is low, but it only has 3.2 W / m. -1 K -1 Thermal conductivity.

[0118] Comparative Example 3

[0119] This example provides a method for preparing a thermally conductive gel with a thermal interface, including the following steps:

[0120] S1. Mix monohydroxy double-terminated perfluoropolyether (molecular weight 4000) and isophorone diisocyanate at a mass ratio of 100:7 to prepare a thermally conductive gel prepolymer.

[0121] The structure of the single-hydroxyl double-terminated perfluoropolyether is the same as in Example 1;

[0122] S2. Micron-sized alumina particles, nano-sized alumina particles, n-hexane, and fluorosilane were sheared and mixed at a mass ratio of 10:4:50:0.2 for 6 hours to modify the micron-sized and nano-sized alumina particles. The suspension was centrifuged at 8000 rpm for 10 minutes to collect the precipitate, which was then washed twice with deionized water to obtain micro / nano thermally conductive particles.

[0123] S3. The thermally conductive gel prepolymer and micro / nano thermally conductive particles are mechanically stirred at a mass ratio of 10:10 for 6 hours. Then, 0.5% of the mass of dibutyltin dilaurate catalyst is added to the thermally conductive gel prepolymer, stirred for 10 minutes, and ultrasonically defoamed for 10 minutes to prepare the thermally conductive gel micro / nano composite.

[0124] S4. The thermally conductive gel micro-nano composite is first heated at 60℃ for 2 hours, and then heated at 80℃ for 12 hours to complete the urethane reaction and obtain the thermal interface thermally conductive gel.

[0125] The interfacial thermal resistance of this thermally conductive gel increased to 1.25 cm. 2 KW -1 Meanwhile, due to its inability to flow after polymerization, the thermally conductive gel contains air bubbles, achieving only 2.5 W / m². -1 K -1 The thermal conductivity is significantly reduced. The adhesion of the thermally conductive gel to the interface is greatly diminished, almost to 0 kPa. The energy absorption damping effect of hydrogen-bonded clusters is also reduced to 200 J·m. -1 Its electrical breakdown resistance can reach 24.2kV / mm.

[0126] Comparative Example 4

[0127] This example provides a method for preparing a thermally conductive gel with a thermal interface, including the following steps:

[0128] S1. Mix dihydroxy single-terminated perfluoropolyether (molecular weight 4000) and isophorone diisocyanate at a mass ratio of 100:7 to prepare a thermally conductive gel prepolymer.

[0129] The structure of the dihydroxy-terminated perfluoropolyether is the same as in Example 1;

[0130] S2. Micron-sized alumina particles, nano-sized alumina particles, n-hexane, and fluorosilane were sheared and mixed at a mass ratio of 10:4:50:0.2 for 6 hours to modify the micron-sized and nano-sized alumina particles. The suspension was centrifuged at 8000 rpm for 10 minutes to collect the precipitate, which was then washed twice with deionized water to obtain micro / nano thermally conductive particles.

[0131] S3. The thermally conductive gel prepolymer and micro / nano thermally conductive particles are mechanically stirred at a mass ratio of 10:10 for 6 hours. Then, 0.5% of the mass of dibutyltin dilaurate catalyst is added to the thermally conductive gel prepolymer, stirred for 10 minutes, and ultrasonically defoamed for 10 minutes to prepare the thermally conductive gel micro / nano composite.

[0132] S4. The thermally conductive gel micro-nano composite is first heated at 60℃ for 2 hours, and then heated at 80℃ for 12 hours to complete the urethane reaction and obtain the thermal interface thermally conductive gel.

[0133] Because the prepolymer of the thermally conductive gel lacks monohydroxyl-terminated perfluoropolyether, the nano-hydrogen-bonded clusters inside the thermally conductive gel cannot be connected by urethane bonds, resulting in a lack of cohesion within the gel and causing it to flow at 25 degrees Celsius. After repeated use, the thermally conductive gel will leak and seep out at the thermal interface due to the extrusion effect.

[0134] Comparative Example 5

[0135] This example provides a method for preparing a thermally conductive gel with a thermal interface, including the following steps:

[0136] S1. Mix dihydroxy mono-terminated perfluoropolyether (molecular weight 4000), monohydroxy di-terminated perfluoropolyether (molecular weight 4000), isophorone diisocyanate, and dibutyltin dilaurate in a mass ratio of 100:25:7:0.7 to prepare a thermally conductive gel prepolymer solution.

[0137] The structures of the dihydroxy single-terminated perfluoropolyether and the monohydroxy double-terminated perfluoropolyether are the same as in Example 1;

[0138] S4. The thermally conductive gel prepolymer solution is heated at 60℃ for 2 hours and then at 80℃ for 12 hours to complete the urethane reaction and obtain the thermal interface thermally conductive gel.

[0139] Because the thermally conductive gel lacks internal thermally conductive particles, it cannot achieve an effective heat conduction path, and therefore only has a thermal conductivity of 0.35 W / m². -1 K -1 Thermal conductivity.

[0140] To further verify the thermal conductivity of the thermal interface gel, three sets of control experiments were designed: a blank group (without thermal interface material), a commercial thermal grease group, and a thermal interface gel group (Example 1). Before testing, each group was uniformly coated on the surface of the electronic device being tested, and a thermocouple thermometer was fixed between the electronic device and the thermal interface material. A heat sink and a cooling fan were fixed above the thermal interface material. A thermal conductivity of 2000 W / m was applied to the electronic device. 2 Electrothermal power is used to measure the temperature change on the surface of electronic devices when they are in a steady state. The results are as follows: Figure 5 As shown in the figure, the surface temperature of the electronic devices in the blank group increased from 20℃ to 98℃, the surface temperature of the electronic devices in the commercial thermal grease group increased from 20℃ to 85℃, while the surface temperature of the electronic devices in the thermal interface thermal gel group only increased from 20℃ to 74℃, demonstrating a significant advantage in heat dissipation. Meanwhile, as... Figure 6 As shown, temperature tests of the cooling fan above the electronic device using an infrared camera also confirmed that the fan with thermal interface thermal conductive gel as the thermal interface material has stronger heat dissipation capacity and can keep the overall electronic device stably within a safe operating temperature range.

[0141] To further verify the material's stability, temperature cycling tests were conducted on the thermally conductive gel at the thermal interface, and the results are as follows: Figure 7 The thermal interface thermal conductive gel, sandwiched between the thermal testing interface and the heat sink equipment, is approximately 100 μm thick. After 100 cycles between 25°C and 85°C, it still maintains normal operation, demonstrating excellent temperature stability.

[0142] Based on the experimental data above, it is evident that the thermal interface gel prepared in this invention possesses multi-dimensional performance advantages, comprehensively adapting to the thermal management needs of electronic devices. Regarding its core thermal conductivity, it effectively optimizes existing thermal systems, resolving thermal conduction obstacles between heat sources and radiators. In terms of electrical safety, its resistance to electrical breakdown can block current leakage paths, preventing damage to electronic devices due to leakage. Compared to traditional thermal interface materials (such as thermal pads and phase change materials), the high adhesion of this thermal interface gel solves interface problems under dynamic operating conditions. This is because traditional thermal interface materials often suffer from insufficient adhesion to the substrate, leading to detachment or increased gaps during equipment vibration and thermal cycling, resulting in a sharp drop in thermal conductivity. The thermal interface gel, however, achieves dynamic and tight bonding at the interface. Furthermore, electronic devices may face risks such as mechanical impact and chemical corrosion during transportation, installation, and use. The impact-resistant properties of the thermal interface gel reduce the damage to the thermal management system caused by the external environment, further expanding the application scenarios of thermal interface materials and avoiding the negative impacts of external impact and corrosion.

[0143] From a specific application perspective, in the field of power battery thermal management, the high thermal conductivity of the thermal interface thermal conductive gel can quickly dissipate the heat generated during battery operation, its electrical breakdown resistance can prevent battery short circuits, its adhesion is suitable for long-term vibration conditions of battery packs, and its shock resistance can cope with bumps and collisions during vehicle operation, comprehensively ensuring battery safety and range stability. In the field of chip packaging, its high thermal conductivity can solve the heat dissipation problem of high power density chips, its electrical breakdown resistance and high adhesion are suitable for the precision connection requirements between chips and substrates, and its shock resistance can also reduce the damage to chips caused by mechanical stress during packaging, effectively improving chip reliability.

[0144] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for preparing a thermal interface conductive gel having temperature responsiveness and self-filling property, characterized by, Comprising the following steps: S1, the dihydroxy monomer, monohydroxy double-terminated monomer and diisocyanate are mixed sufficiently to obtain a heat-conducting gel prepolymer solution; S2, micron heat-conducting particles, nano heat-conducting particles, solvent and fluorosilane are mixed in proportion, the micron heat-conducting particles and nano heat-conducting particles are modified by fluorosilane, centrifuged, the precipitate is collected, washed with deionized water, and micron-nano heat-conducting particles are obtained; S3, the heat-conducting gel prepolymer solution and micron-nano heat-conducting particles are mixed in proportion, mechanically stirred, tin catalyst is added, mixed, ultrasonic defoaming is performed, and a heat-conducting gel micron-nano composite is obtained; S4, the heat-conducting gel micron-nano composite is subjected to gradient heating to perform urethane reaction, and a thermal interface heat-conducting gel is obtained; The dihydroxy monomer has a molecular weight of 1000-8000 and is selected from the structures shown in formula I: I； R1is selected from , , , one of the following: n1 is an integer of 10-40, n2 and n5 are integers of 10-50, and n3 and n4 are integers of 5-20; The monohydroxy double-terminated monomer has a molecular weight of 1000-8000 and is selected from the structures shown in formula II: II; R2is selected from , , , one of the following: n6, n7, n9 and n10 are integers of 5-20, and n8 and n11 are integers of 10-50; The molar ratio of the dihydroxy monomer and the monohydroxy double-terminated monomer is 1:0.1-1; The ratio of the sum of the molar amounts of the dihydroxy monomer and the monohydroxy double-terminated monomer to the molar amount of diisocyanate is maintained at 1:1-1.05; The mass ratio of the micron heat-conducting particles, nano heat-conducting particles, solvent and fluorosilane is 10:2-10:50:0.2; The mass ratio of the heat-conducting gel prepolymer solution and micron-nano heat-conducting particles is 10:2-10.

2. The production method according to claim 1, characterized by, The diisocyanate is selected from one of 4,4'-methylenebis(cyclohexyl isocyanate), 1,3-bis(1-isocyanato-1-methylethyl)benzene, isophorone diisocyanate, hexamethylene diisocyanate, and 1,3-bis(isocyanatomethyl)cyclohexane.

3. The production method according to claim 1, characterized by, The micron heat-conducting particles are selected from one or more of alumina particles, magnesium oxide particles, boron nitride microspheres, zinc oxide particles, silicon carbide particles, and aluminum nitride particles; The nano heat-conducting particles are selected from one or more of alumina particles, zinc oxide particles, magnesium oxide particles, silicon carbide particles, and aluminum nitride particles; The solvent is selected from one or more of n-heptane, n-hexane, cyclohexane, and toluene; The fluorosilane is selected from one or more of perfluorooctyltriethoxysilane, 1H,1H,2H,2H-perfluorooctyltrimethoxysilane, 3-aminopropyltriethoxysilane, and 3-(methacryloyloxy)propyltrimethoxysilane.

4. The production method according to claim 1, characterized by, In step S2, the modification time is 3-6 h.

5. The preparation method according to claim 1, characterized in that, The tin catalyst is added in an amount of 0.4-0.6 wt% of the mass of the heat-conducting gel prepolymer solution.

6. The method of claim 1, wherein, In step S4, the gradient heating is first incubated at 50-70℃ for 1.5-2.5 h, and then incubated at 75-90℃ for 10-15 h.

7. A thermal interface conductive gel having temperature responsiveness and self-filling property, characterized by, Prepared by the preparation method of any one of claims 1-6.

8. Use of the thermal interface heat-conducting gel of claim 7 in the preparation of a heat-conducting material for microelectronic devices.

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