Integrated multifunctional thermal interface composite material as well as preparation method and application thereof

Abstract

The invention discloses an integrated multifunctional thermal interface composite material and a preparation method and application thereof, and raw materials of the integrated multifunctional thermal interface composite material comprise the following components: a substrate which is an aluminum foil, a copper foil or a passivated magnesium foil; a solvent of the seed solution is absolute ethyl alcohol or isopropyl alcohol, and 1-1.5 mg of zinc salt and 0.2-0.3 mg of alkali are dissolved in each 100 ml of the solvent; a solvent of the growth solution is absolute ethyl alcohol or ethylene glycol, and 0.5-1.5 g of zinc salt, 0.2-0.8 g of alkali and 0.3-0.9 g of a growth regulator are dissolved in every 100 ml of the solvent; based on 100 ml of the solvent contained in the seed solution and 100 ml of the solvent contained in the growth solution, 25 to 35 g of acrylic acid (AA), 0.375 to 0.525 g of toluene diisocynate (TDI) and 7 to 10 g of ethyl acetate (EA) are included. Through a design strategy of substrate in-situ growth of a network and polymer permeation filling, the prepared composite material has excellent thermal conductivity, efficient electromagnetic shielding performance, good electrical insulating property, high stripping force and excellent structural stability, and can meet the integration requirement of electronic packaging for multiple properties.

Description

Technical Field

[0001] This application relates to the technical field of thermal interface materials (TIMs) for electronic packaging, and more specifically to an integrated multifunctional thermal interface composite material that combines high thermal conductivity, efficient electromagnetic shielding, electrical insulation and strong adhesion, as well as its preparation method and application. Background Technology

[0002] The high-density integration and high-power development of electronic devices have placed stringent requirements on thermal interface materials for "multiple performance synergy": they not only need excellent thermal conductivity to achieve efficient heat dissipation, but also electromagnetic shielding capabilities to avoid signal interference, electrical insulation to ensure safe use, and good interface adhesion and structural stability to meet long-term service requirements.

[0003] In existing technologies, constructing a continuous network of thermally conductive fillers is the mainstream strategy for improving the thermal conductivity of composite materials. However, traditional methods often employ prefabricated filler networks combined with a substrate, resulting in weak coupling between the network and the heat-dissipating substrate (such as metal foil), leading to persistently high interfacial thermal resistance. Furthermore, electromagnetic shielding performance is typically positively correlated with electrical conductivity, while electronic packaging materials require insulation, making it difficult to achieve both simultaneously. Additionally, the introduction of thermally conductive networks often compromises the adhesion properties of the polymer matrix, affecting the reliability of the material in practical applications. Therefore, how to achieve the integration of multiple properties—high thermal conductivity, electromagnetic shielding, electrical insulation, and strong adhesion—through structural design is a critical issue that urgently needs to be addressed in the field of thermal interface materials. Summary of the Invention

[0004] In view of the shortcomings of the prior art, this application aims to provide an integrated multifunctional thermal interface composite material and its preparation method. By using the design of "in-situ growth of zinc oxide ZnO network on substrate + AA infiltration curing", the defects of high interfacial thermal resistance and difficulty in synergistic optimization of performance of traditional thermal interface materials are solved, and the thermal conductivity, electromagnetic shielding, electrical insulation and adhesion are simultaneously improved.

[0005] In a first aspect, this application provides an integrated multifunctional thermal interface composite material, wherein the raw materials of the integrated multifunctional thermal interface composite material include the following components: The substrate is an aluminum foil, copper foil, or passivated magnesium foil; The seed solution is prepared in the form of anhydrous ethanol or isopropanol, and contains 1-1.5 mg of zinc salt and 0.2-0.3 mg of alkali per 100 ml of solvent. The growth solution is a solvent for anhydrous ethanol or ethylene glycol, and contains 0.5-1.5 g zinc salt, 0.2-0.8 g alkali and 0.3-0.9 g growth regulator per 100 ml of solvent. Based on 100ml of solvent in the seed solution and 100ml of solvent in the growth solution, the following amounts were used: AA 25-35 g, TDI 0.375-0.525 g, and EA 7-10 g.

[0006] Preferably, in the seed solution, the zinc salt is selected from zinc acetate dihydrate Zn(CH3COO)2. One or more of 2H2O and zinc chloride Zn(Cl)2, and the base is selected from one or more of sodium hydroxide NaOH, potassium hydroxide KOH and ammonia water.

[0007] Preferably, in the growth solution, the zinc salt is selected from zinc nitrate hexahydrate Zn(NO3)6. One or more of 6H2O and zinc sulfate (ZnSO4), the base is selected from one or more of hexamethylenetetramine (HMTA) and hexamethylenediamine (HMDA), and the growth regulator is selected from one or more of polyethyleneimine (PEI), polyethylene glycol (PEG), and polyvinyl alcohol (PVA).

[0008] Preferably, the composite material has the following performance characteristics: in-plane thermal conductivity ≥ 140 W / m K, vertical thermal conductivity ≥ 2.5 W / m K; Electromagnetic shielding effectiveness SET≥60 dB in the 8.2-12.4 GHz band; Interface thermal resistance Rc≤1.5 K mm² / W; 180° peel force ≥1250 gf / inch; no slippage in 518 h stability test.

[0009] Preferably, the integrated multifunctional thermal interface composite material is an integrated structure of substrate-zinc oxide (ZnO) network-acrylic acid (AA) composite, wherein the zinc oxide (ZnO) network is a continuous three-dimensional network structure, and the acrylic acid (AA) permeates and fills the voids in the zinc oxide (ZnO) network. Secondly, this application provides a method for preparing the above-mentioned integrated multifunctional thermal interface composite material, comprising the following steps: S1. Preparation of seed crystal substrate: The seed solution is drop-coated onto the substrate surface, annealed at 178-182℃, and the drop-coating-annealing cycle is repeated 2-5 times to obtain a seed crystal substrate loaded with zinc oxide ZnO seeds. S2. Preparation of substrate-zinc oxide ZnO network: Immerse the seed crystal substrate obtained in step S1 into the growth solution, keep it at 93-97℃ for 6-10 h, wash and dry at 48-52℃ for 10-14 h to obtain substrate-zinc oxide ZnO network. S3. Preparation of substrate-zinc oxide ZnO network-acrylic acid AA composite material: Mix acrylic acid AA, toluene diisocyanate TDI and ethyl acetate EA in proportion and coat them evenly on the surface of the substrate-zinc oxide ZnO network obtained in step S2. Dry at 78-82℃ for 18-22 min to obtain substrate-zinc oxide ZnO network-acrylic acid AA composite material.

[0010] Preferably, the seed solution in step S1 is prepared as follows: zinc salt and alkali are dissolved in a solvent and heated in a water bath at 63-67°C for 42-47 min to obtain the seed solution; wherein, the zinc salt is selected from zinc acetate dihydrate Zn(CH3COO)2. One or more of 2H2O and zinc chloride Zn(Cl)2, and the base is selected from one or more of sodium hydroxide NaOH, potassium hydroxide KOH and ammonia water.

[0011] Preferably, the growth solution in step S2 is prepared as follows: zinc salt, alkali, and growth regulator are dissolved in a solvent and heated in a water bath at 93-97 °C for 28-32 min to obtain the growth solution; wherein the zinc salt is selected from zinc nitrate hexahydrate Zn(NO3)6. One or more of 6H2O and zinc sulfate (ZnSO4), the base is selected from one or more of hexamethylenetetramine (HMTA) and hexamethylenediamine (HMDA), and the growth regulator is selected from one or more of polyethyleneimine (PEI), polyethylene glycol (PEG), and polyvinyl alcohol (PVA).

[0012] Preferably, in step S3, the coating thickness is 18-22 μm.

[0013] Thirdly, this application provides the application of the above-mentioned integrated multifunctional thermal interface composite material in electronic packaging, the application scenarios of which include chip heat dissipation packaging, lithium-ion battery packaging, and thermal management of flexible electronic devices.

[0014] The integrated multifunctional thermal interface composite material, its preparation method, and its application provided in this application have the following technical advantages: 1. This application employs a design of "in-situ growth of zinc oxide (ZnO) network on the substrate," achieving integrated thermal conductivity network and heat dissipation substrate, significantly reducing interfacial thermal resistance (as low as 1.3 K). (mm² / W), which solves the problem of poor coupling between traditional prefabricated networks and substrates.

[0015] 2. By combining the high electromagnetic reflectivity of the substrate with the multi-interface refractive loss of the zinc oxide (ZnO) network, a high-efficiency electromagnetic shielding of ≥60dB is achieved while ensuring electrical insulation, thus overcoming the performance conflict between "electromagnetic shielding and electrical insulation".

[0016] 3. Acrylic acid (AA) fully penetrates the pores of the zinc oxide (ZnO) network, retaining the polymer's adhesive properties (peel force ≥1250 gf / inch) while enhancing structural stability with the support of the ZnO network. No slippage was observed in the 518-hour stability test, and the performance degradation after damp heat aging was mild.

[0017] 4. The preparation process combines hydrothermal growth with scraping curing, which is simple, easy to control parameters, requires no complex equipment, and is easy to scale up; the raw material cost is low, and both zinc oxide (ZnO) and the substrate have good environmental compatibility.

[0018] The following will further explain the concept, specific structure and technical effects of this application in conjunction with the accompanying drawings, so as to fully understand the purpose, features and effects of this application. Attached Figure Description

[0019] Figure 1 This is a surface morphology diagram of the substrate aluminum foil.

[0020] Figure 2 This is a surface morphology image of zinc oxide (ZnO) seeds on aluminum foil.

[0021] Figure 3 This is a surface morphology diagram of the zinc oxide (ZnO) network on aluminum foil. Detailed Implementation

[0022] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, unless otherwise specified, the following embodiments and features in the embodiments can be combined with each other.

[0023] Some exemplary embodiments of this application have been described for illustrative purposes. It should be understood that this application may be implemented in other ways not specifically shown in the accompanying drawings.

[0024] The core design principle of this application is as follows: 1. Integrated thermal conductivity structure design: A continuous zinc oxide (ZnO) network is grown in situ on the substrate surface, allowing the thermally conductive network to bond directly to the heat dissipation substrate, reducing interfacial contact thermal resistance. Simultaneously, the ZnO network provides a continuous channel for heat transfer, working in conjunction with the substrate's high thermal conductivity to achieve an in-plane thermal conductivity of 147 W / m. K, Vertical plane 2.8 W / m K has excellent thermal conductivity.

[0025] 2. Synergistic electromagnetic shielding mechanism: The substrate (aluminum foil, copper foil or passivated magnesium foil) serves as a highly conductive substrate, which strongly reflects electromagnetic waves (reflection loss SER); the heterogeneous interface formed by the zinc oxide (ZnO) network and acrylic acid (AA) generates polarization loss, and the network structure extends the electromagnetic wave propagation path, enhancing absorption loss (SEA). The two work together to achieve a shielding effectiveness of ≥60 dB, while the insulating properties of acrylic acid (AA) ensure the overall electrical insulation of the material.

[0026] 3. Structure-Adhesion Synergistic Optimization: Acrylic acid (AA) fully penetrates the voids of the zinc oxide (ZnO) network to form a composite structure of "network support-polymer filling". This not only improves the structural stability of the material with the help of the zinc oxide (ZnO) network, but also retains the high adhesion of acrylic acid (AA) and avoids the damage to the bonding performance caused by thermally conductive fillers.

[0027] The raw materials for the integrated multifunctional thermal interface composite material of this application include the following components: substrate, seed liquid, growth liquid, and coating raw materials.

[0028] The substrate is aluminum foil, copper foil, or passivated magnesium foil. In the field of growing zinc oxide (ZnO) nanostructures, especially highly oriented nanowire arrays via hydrothermal methods, aluminum foil, copper foil, or passivated magnesium foil substrates are unconventional choices. The main reasons are: ① unstable surface chemistry; ② undesirable surface morphology; ③ lack of lattice matching at the interface. Choosing aluminum foil, copper foil, or passivated magnesium foil as the substrate overcomes the following obstacles: ① Overcoming the corrosion problem of aluminum foil, copper foil, or passivated magnesium foil in hydrothermal environments; ② Achieving the growth of functional structures on rough surfaces without lattice matching, forming a three-dimensional interconnected network. The rough surfaces and randomly oriented seeds of aluminum foil, copper foil, or passivated magnesium foil are ideal templates for forming interwoven, randomly oriented nanonetworks; ③ As thermal interface materials, aluminum foil, copper foil, or passivated magnesium foil are good conductors with a certain degree of flexibility. Compared with the brittleness and low thermal conductivity of FTO glass, they are more suitable for the thermal management scenarios of practical electronic devices; ④ Aluminum foil, copper foil, or passivated magnesium foil are inexpensive and readily available industrial raw materials. Using them directly as substrates and functional components can simplify device structures and reduce manufacturing costs; ⑤ The final product, "substrate-zinc oxide ZnO network-acrylic AA composite material," is an integrated functional structure in which aluminum foil, copper foil, or passivated magnesium foil serves as both a supporting substrate and part of the thermal conduction pathway, which is impossible to achieve in existing solutions using FTO glass.

[0029] Aluminum foil, copper foil, or passivated magnesium foil have rough surfaces with numerous grain boundaries, scratches, and wrinkles at the microscopic level. When drop-coated onto a rough surface, the seed solution accumulates in the grooves, while the coverage is thinner at the protrusions. This results in an uneven ZnO seed layer with random orientation of the seed grains, lacking a uniform preferred orientation. Furthermore, a thin, dense amorphous material (e.g., Al₂O₃) forms on the substrate in the air. This amorphous material has a completely different crystal structure from ZnO and exhibits no lattice matching. Without lattice guidance, the ZnO seed grains nucleate randomly on the amorphous surface, and subsequent hydrothermal growth is based on these randomly oriented seeds, naturally preventing the formation of a uniform vertical array.

[0030] The seed culture is an anhydrous ethanol or isopropanol solution, containing 1-1.5 mg of zinc salt and 0.2-0.3 mg of alkali per 100 ml of solvent (anhydrous ethanol or isopropanol). The zinc salt is selected from zinc acetate dihydrate Zn(CH3COO)2. One or more of 2H2O and zinc chloride Zn(Cl)2, with the zinc salt preferably at 1.1 mg. The alkali is selected from one or more of sodium hydroxide NaOH, potassium hydroxide KOH, and ammonia water, preferably at 0.24 mg.

[0031] The growth medium is an anhydrous ethanol or ethylene glycol solution, containing 0.5-1.5 g of zinc salt, 0.2-0.8 g of alkali, and 0.3-0.9 g of growth regulator per 100 ml of solvent (anhydrous ethanol or ethylene glycol). The zinc salt is selected from zinc nitrate hexahydrate Zn(NO3)6. One or more of 6H2O and zinc sulfate (ZnSO4), preferably 1g of zinc salt. The alkali is selected from one or more of hexamethylenetetramine (HMTA) and hexamethylenediamine (HMDA), preferably 0.5g. The growth regulator is selected from one or more of polyethyleneimine (PEI), polyethylene glycol (PEG), and polyvinyl alcohol (PVA), preferably 0.6g.

[0032] The coating raw materials include acrylic acid (AA), toluene diisocyanate (TDI), and ethyl acetate (EA). Based on 100 ml of solvent in the seed solution and 100 ml of solvent in the growth solution: the amount of acrylic acid (AA) is 25-35 g, preferably 30 g; the amount of toluene diisocyanate (TDI) is 0.375-0.525 g, preferably 0.45 g; and the amount of ethyl acetate (EA) is 7-10 g, preferably 8 g.

[0033] The integrated multifunctional thermal interface composite material obtained in this application is an integrated structure of substrate-zinc oxide (ZnO) network-acrylic acid (AA) composite. The zinc oxide (ZnO) network is a continuous three-dimensional network structure. The acrylic acid (AA) completely penetrates and fills the voids of the zinc oxide (ZnO) network to form a zinc oxide (ZnO)-acrylic acid (AA) composite layer. The thickness of the composite layer is highly matched with that of the ZnO network. The total adhesive layer thickness is 18-22 μm, preferably 20 μm.

[0034] The composite material obtained in this application meets the following performance requirements: in-plane thermal conductivity ≥140 W / m K, vertical thermal conductivity ≥ 2.5 W / m K; Electromagnetic shielding effectiveness SET≥60 dB in the 8.2-12.4 GHz band; Interface thermal resistance Rc≤1.5 K mm² / W; 180° peel force ≥1250 gf / inch; no slippage in 518 h stability test.

[0035] The substrate (aluminum foil, copper foil, or passivated magnesium foil) used in this application has the thickness of conventional electronic packaging, the height of the zinc oxide (ZnO) network is 10-50 μm, and the coating thickness of the zinc oxide (ZnO)-acrylic acid (AA) composite layer is 18-22 μm, preferably 20 μm.

[0036] The preparation method of the above-mentioned integrated multifunctional thermal interface composite material of this application includes the following steps: Step 1: Prepare seed solution The zinc salt and alkali of the above dosage are dissolved in a solvent (anhydrous ethanol or isopropanol) and heated in a water bath at 63-67°C (preferably 65°C) for 42-47 min (preferably 45 min) to obtain the seed solution; wherein the zinc salt is selected from zinc acetate dihydrate Zn(CH3COO)2. One or more of 2H2O and zinc chloride Zn(Cl)2, and the base is selected from one or more of sodium hydroxide NaOH, potassium hydroxide KOH and ammonia water.

[0037] Step 2: Preparation of seed crystal substrate The seed solution is drop-coated onto the substrate surface and annealed at 178-182℃ (preferably 180℃). The drop-coating-annealing cycle is repeated 2-5 times (preferably 3 times) to obtain a seed crystal substrate loaded with zinc oxide (ZnO) seeds.

[0038] Step 3: Preparation of growth solution The zinc salt, alkali, and growth regulator are dissolved in a solvent (anhydrous ethanol or ethylene glycol) and heated in a water bath at 93-97°C (preferably 95°C) for 28-32 minutes (preferably 30 minutes) to obtain the growth solution; wherein the zinc salt is selected from zinc nitrate hexahydrate Zn(NO3)6. One or more of 6H2O and zinc sulfate (ZnSO4), the base is selected from one or more of hexamethylenetetramine (HMTA) and hexamethylenediamine (HMDA), and the growth regulator is selected from one or more of polyethyleneimine (PEI), polyethylene glycol (PEG), and polyvinyl alcohol (PVA).

[0039] The substrate is a reactive metal. Although it has an oxide layer on its surface, this layer can be destroyed in acidic or alkaline aqueous solutions at 95°C, leading to substrate corrosion. This corrosion results in: ① damage to the seed layer and substrate, preventing continuous ZnO growth; ② introduction of Al³⁺. + Introducing hydrogen into the growth solution can interfere with the nucleation and crystallization process of zinc oxide (ZnO), potentially generating impurities and preventing the formation of a regular nanostructure; ③ the generation of hydrogen gas can also damage the growing ZnO structure. This application selects anhydrous ethanol or ethylene glycol. Anhydrous ethanol or ethylene glycol has lower polarity than water, significantly reducing the crystal growth rate, especially the longitudinal growth rate along the Z-axis; simultaneously, it may not be as effective as a growth regulator in completely suppressing lateral growth. This "slowed-down" and more "balanced" growth kinetics, however, is beneficial for ZnO crystals to branch and connect to a certain extent in various directions, thus making it easier to form a three-dimensional cross-linked nanonetwork structure rather than isolated nanowires. This network structure, when used as a thermal interface material, exhibits better mechanical flexibility and more contact points.

[0040] This application intentionally selected a "non-optimal," relatively low concentration of growth regulator. This concentration may be sufficient to regulate morphology and prevent excessive crystal growth, but not enough to completely suppress lateral bonding, thus actively guiding the formation of the network structure. Furthermore, the segmental conformation of the growth regulator in the ethanol or ethylene glycol phase of this application, its adsorption capacity on the zinc oxide (ZnO) crystal surface, and its interaction with the growth precursor are all unknown and poorly studied. This application creatively identified a growth regulator concentration window in this specific environment that precisely generates the ideal network structure.

[0041] Step 4: Preparation of substrate-zinc oxide (ZnO) network The seed crystal substrate obtained in step two is immersed in the growth solution obtained in step three and kept at 93-97℃ (preferably 95℃) for 6-10 h (8 h). After rinsing with deionized water / anhydrous ethanol, it is dried at 48-52℃ (preferably 50℃) for 10-14 h (preferably 12 h) to obtain the substrate-zinc oxide ZnO network.

[0042] In the ethanol or ethylene glycol system of this application, the low ion mobility in ethanol or ethylene glycol alters the hydrolysis pathway of hexamethylenetetramine (HMTA) or hexamethylenediamine (HMDA), resulting in a crystal growth rate much lower than in the aqueous system. Excessive growth time leads to overgrowth, causing the network structure to become overly dense and fragile, and even uncontrollable aggregation due to prolonged exposure to high temperatures. Therefore, the 6-10 hour timeframe chosen in this application is experimentally verified as the optimal time for forming the ideal three-dimensional network structure without causing other problems.

[0043] Ethanol, as a simple subsequent washing solvent, is more easily evaporated and removed during the subsequent drying process at 48-52℃, reducing the presence of stubborn organic residues at the source. Therefore, high-temperature annealing is not required for "purification".

[0044] Step 5: Preparation of substrate-zinc oxide (ZnO) network-acrylic acid (AA) composite material Acrylic acid (AA), toluene diisocyanate (TDI), and ethyl acetate (EA) are mixed evenly in proportion and coated onto the substrate-zinc oxide (ZnO) network surface obtained in step four. The mixture is then dried at 78-82°C (preferably 80°C) for 18-22 min (20 min) to obtain the substrate-zinc oxide (ZnO) network-acrylic acid (AA) composite material, wherein the coating thickness is controlled to be 18-22 μm (preferably 20 μm).

[0045] Example 1 raw material: Substrate: Aluminum foil (morphology as follows) Figure 1 (as shown) Seed liquid raw material: Zn(CH3COO)2 2H2O (1.1 mg), NaOH (0.24 mg), anhydrous ethanol (100 ml); Growth medium raw material: Zn(NO3)6 6H2O (1 g), HMTA (0.5 g), PEI (0.6 g), anhydrous ethanol (100 ml); AA (30 g), TDI (0.45 g), ethyl acetate (8 g).

[0046] Step 1: Prepare seed solution 1.1 mg Zn(CH3COO)2 2H2O and 0.24 mg NaOH were added sequentially to 100 ml of anhydrous ethanol and stirred (300 rpm) until completely dissolved. The solution was then heated in a 65°C water bath for 45 min and allowed to cool naturally to room temperature to obtain a uniform and transparent seed solution.

[0047] Step 2: Preparation of seed crystal substrate The seed solution was evenly dropped onto the surface of aluminum foil (coating amount: 0.1 ml / cm²). 3 After coating, the aluminum foil is annealed in a 180 ℃ oven for 15 min. After cooling, the drop-coating-annealing cycle is repeated 3 times to ensure that the aluminum foil surface is uniformly loaded with ZnO seeds, thus obtaining a seed crystal substrate loaded with zinc oxide ZnO seeds, as shown below. Figure 2 As shown.

[0048] Step 3: Preparation of growth solution 1g Zn(NO3)6 Add 6H2O, 0.5 g HMTA, and 0.6 g PEI to 100 ml of anhydrous ethanol, stir magnetically (500 rpm) until the solid is completely dissolved, heat in a 95°C water bath for 30 min, and cool to 60°C to obtain a clear growth solution.

[0049] Step 4: Preparation of substrate-zinc oxide (ZnO) network The seed crystal substrate was immersed in the growth solution (the liquid level covered the substrate) and placed in a 95℃ constant temperature reaction chamber for 8 hours for hydrothermal growth. After the reaction, the aluminum foil was removed and rinsed three times alternately with deionized water and anhydrous ethanol to remove residual impurities on the surface. Then it was dried in a 50℃ oven for 12 hours to obtain the substrate-zinc oxide ZnO network intermediate (ZnO network height approximately 10-50 μm).

[0050] Step 5: Preparation of substrate-zinc oxide (ZnO) network-acrylic acid (AA) composite material 30 g AA, 8 g ethyl acetate, and 0.45 g TDI were mixed evenly in proportion, dispersed at high speed (400 rpm) for 10 min, and then coated onto the substrate-zinc oxide ZnO network surface (coating speed 300 mm / min). After drying at 80℃ for 20 min, crosslinking and curing were completed to obtain the substrate-zinc oxide ZnO network-acrylic AA composite material.

[0051] Comparative Example 1.1 Except for skipping steps two through four of zinc oxide (ZnO) network growth and directly coating the AA mixed slurry onto the aluminum foil surface, the remaining steps are the same as in Example 1 to prepare the aluminum foil-AA acrylic composite material.

[0052] Comparative Example 1.2 Except for the absence of PEI in the growth solution, the other steps were the same as in Example 1 to prepare a substrate-zinc oxide ZnO network-acrylic AA composite material (zinc oxide ZnO is a discrete rod structure without a continuous network).

[0053] The performance of the composite material prepared in Example 1 was tested: 1. Thermal properties: The in-plane thermal conductivity was measured using a Netzsch LF427 thermal conductivity meter, and was 147 W / m. K, the thermal conductivity in the vertical plane is 2.8 W / m K; the interfacial thermal resistance (Rc) is 1.1 K. mm² / W.

[0054] 2. Electromagnetic shielding performance: The total shielding effectiveness (SET) in the 8.2-12.4 GHz frequency band was tested using a vector network analyzer. The total shielding effectiveness (SET) was 60-65 dB, with reflection loss (SER) and absorption loss (SEA) contributing to the overall performance.

[0055] 3. Adhesion performance: 180° peel test (width 25.4 mm, peel speed 300 mm / min), peel force is 1350 gf / inch, no adhesive residue after peeling.

[0056] 4. Structural stability: No slippage was observed during the 518-hour stability test (2000 g roller pressing, 1000 g weight suspension); after PCT 48-hour damp heat aging (85℃, 85% RH), the peel force decreased to 1200 gf / inch, with a performance degradation rate of approximately 11%.

[0057] 5. Electrical insulation: Tested by a dielectric spectrometer, it maintains good electrical insulation properties and no conductive path is formed.

[0058] Performance tests in Comparative Example 1.1 show that the thermal conductivity on the vertical surface is only 1.5 W / m. K, with an interface thermal resistance as high as 33.3 K. With an electromagnetic shielding effectiveness of only 30-35 dB and a diameter of mm² / W, the ZnO network demonstrates its crucial role in enhancing thermal conductivity and electromagnetic shielding.

[0059] Performance tests in Comparative Example 1.2 show that the thermal conductivity on the vertical surface is 1.8 W / m. K, with an electromagnetic shielding effectiveness of 40-45 dB, and slight slippage observed in structural stability testing, proves that the continuous ZnO network under PEI regulation is the core of performance synergy.

[0060] Example 2 raw material: Substrate: Copper foil; Seed liquid ingredients: Zn(Cl)2 (1 mg), KOH (0.2 mg), isopropanol (100 ml); Growth medium ingredients: ZnSO4 (0.5 g), HMDA (0.2 g), PEG (0.3 g), ethylene glycol (100 ml); AA (25 g), TDI (0.375 g), ethyl acetate (7 g).

[0061] Step 1: Prepare seed solution 1 mg Zn(Cl)2 and 0.2 mg KOH were added sequentially to 100 ml of isopropanol and stirred (300 rpm) until completely dissolved. The solution was then heated in a 63°C water bath for 42 min and allowed to cool naturally to room temperature to obtain a uniform and transparent seed solution.

[0062] Step 2: Preparation of seed crystal substrate The seed solution was evenly dropped onto the surface of copper foil (coating amount: 0.1 ml / cm²). 3 After coating, the copper foil is placed in an oven at 178 ℃ for annealing for 15 min. After cooling, the drop coating-annealing cycle is repeated twice to ensure that the copper foil surface is uniformly loaded with ZnO seeds, thus obtaining a seed crystal substrate loaded with zinc oxide ZnO seeds.

[0063] Step 3: Preparation of growth solution Add 0.5 g ZnSO4, 0.2 g HMDA, and 0.3 g PEG to 100 ml ethylene glycol and stir magnetically (500 rpm) until the solid is completely dissolved. Then heat in a 97°C water bath for 28 min and cool to 60°C to obtain a clear growth solution.

[0064] Step 4: Preparation of substrate-zinc oxide (ZnO) network The seed crystal substrate was immersed in the growth solution (the liquid level covered the substrate) and placed in a 93℃ constant temperature reaction chamber for 6 hours for hydrothermal growth. After the reaction, the copper foil was removed and rinsed three times alternately with deionized water and anhydrous ethanol to remove residual impurities on the surface. Then it was dried in a 48℃ oven for 10 hours to obtain the substrate-zinc oxide ZnO network intermediate (ZnO network height approximately 10-50 μm).

[0065] Step 5: Preparation of substrate-zinc oxide (ZnO) network-acrylic acid (AA) composite material 25 g AA, 7 g ethyl acetate and 0.375 g TDI were mixed evenly in proportion, dispersed at high speed (400 rpm) for 10 min and then coated onto the substrate-zinc oxide ZnO network surface (coating speed 300 mm / min). After drying at 78℃ for 18 min, crosslinking and curing were completed to obtain the substrate-zinc oxide ZnO network-acrylic AA composite material.

[0066] Comparative Example 2.1 Except for skipping steps two through four of ZnO network growth and directly coating the AA mixed slurry onto the Cu foil surface, the remaining steps are the same as in Example 2 to prepare the AA / Cu foil composite material.

[0067] Comparative Example 2.2 Except for the absence of PEI in the growth solution, the remaining steps were the same as in Example 2 to prepare ZnO@AA / Cu foil composite material (ZnO is a discrete rod structure without a continuous network).

[0068] The performance of the composite material prepared in Example 2 was tested: 1. Thermal properties: In-plane thermal conductivity is 145 W / m K, the thermal conductivity of the vertical plane is 2.7 W / m K; the interfacial thermal resistance (Rc) is 1.6 K. mm² / W.

[0069] 2. Electromagnetic shielding performance: The total shielding effectiveness (SET) in the 8.3-12.4 GHz band is 59-64 dB.

[0070] 3. Adhesion performance: 180° peel force is 1520 gf / inch, and no adhesive residue remains after peeling.

[0071] 4. Structural stability: No slippage was observed during the 520-hour stability test; after 48 hours of PCT damp heat aging, the peel strength decreased to 1390 gf / inch, with a performance degradation rate of approximately 8.6%.

[0072] 5. Electrical insulation: Tested by a dielectric spectrometer, it maintains good electrical insulation properties and no conductive path is formed.

[0073] Performance tests in Comparative Example 2.1 show that the thermal conductivity on the vertical surface is only 1.3 W / m. K, with an interface thermal resistance as high as 34.2 K. With an electromagnetic shielding effectiveness of only 29-34 dB and a diameter of mm² / W, the ZnO network demonstrates its crucial role in enhancing thermal conductivity and electromagnetic shielding.

[0074] Performance tests in Comparative Example 2.2 show that the thermal conductivity on the vertical surface is 1.6 W / m. K, with an electromagnetic shielding effectiveness of 38-43 dB, showed slight slippage in the structural stability test, proving that the continuous ZnO network under PEI regulation is the core of performance synergy.

[0075] Example 3 raw material: Substrate: Passivated magnesium foil; Seed liquid raw material: Zn(CH3COO)2 2H2O (1.5 mg), NaOH (0.3 mg), anhydrous ethanol (100 ml); Growth medium raw material: Zn(NO3)6 6H2O (1.5 g), HMTA (0.8 g), PVA (0.9 g), anhydrous ethanol (100 ml); AA (35 g), TDI (0.525 g), ethyl acetate (10 g).

[0076] Step 1: Prepare seed solution 1.5 mg Zn(CH3COO)2 2H2O and 0.3 mg NaOH were added sequentially to 100 ml of anhydrous ethanol and stirred (300 rpm) until completely dissolved. The solution was then heated in a 67°C water bath for 42 min and allowed to cool naturally to room temperature to obtain a homogeneous and transparent seed solution.

[0077] Step 2: Preparation of seed crystal substrate The seed solution was evenly drop-coated onto the surface of passivated magnesium foil (coating amount: 0.1 ml / cm²). 3 After coating, the passivated magnesium foil is placed in an oven at 182 ℃ for annealing for 15 min. After cooling, the drop coating-annealing cycle is repeated 5 times to ensure that the copper foil surface is uniformly loaded with ZnO seeds, thus obtaining a seed crystal substrate loaded with zinc oxide ZnO seeds.

[0078] Step 3: Preparation of growth solution 1.5 g Zn(NO3)6 6H2O, 0.8 g HMTA, and 0.9 g PVA were added to 100 ml of anhydrous ethanol and magnetically stirred (500 rpm) until the solid was completely dissolved. The mixture was then heated in a 97°C water bath for 32 min and cooled to 60°C to obtain a clear growth solution.

[0079] Step 4: Preparation of substrate-zinc oxide (ZnO) network The seed crystal substrate was immersed in the growth solution (the liquid level covered the substrate) and placed in a 97℃ constant temperature reaction chamber for 10 h for hydrothermal growth. After the reaction was completed, the passivated magnesium foil was removed and rinsed three times alternately with deionized water and anhydrous ethanol to remove residual impurities on the surface. Then it was dried in a 48℃ oven for 10 h to obtain the substrate-zinc oxide ZnO network intermediate (ZnO network height approximately 10-50 μm).

[0080] Step 5: Preparation of substrate-zinc oxide (ZnO) network-acrylic acid (AA) composite material 35 g AA, 10 g ethyl acetate and 0.525 g TDI were mixed evenly in proportion, dispersed at high speed (400 rpm) for 10 min and then coated onto the substrate-zinc oxide ZnO network surface (coating speed 300 mm / min). After drying at 82℃ for 22 min, crosslinking and curing were completed to obtain the substrate-zinc oxide ZnO network-acrylic AA composite material.

[0081] Comparative Example 3.1 Except for skipping steps two through four of ZnO network growth and directly coating the AA mixed slurry onto the surface of the passivated magnesium foil, the remaining steps are the same as in Example 3 to prepare the AA / passivated Mg foil composite material.

[0082] Comparative Example 3.2 Except for the absence of PEI in the growth solution, the remaining steps were the same as in Example 3 to prepare ZnO@AA / passivated Mg foil composite material (ZnO is a discrete rod structure without a continuous network).

[0083] The performance of the composite material prepared in Example 3 was tested: 1. Thermal properties: In-plane thermal conductivity is 140 W / m K, the thermal conductivity in the vertical plane is 2.3 W / m K; the interfacial thermal resistance (Rc) is 1.2 K. mm² / W.

[0084] 2. Electromagnetic shielding performance: The total shielding effectiveness (SET) in the 8.2-12.4GHz frequency band is 55-63 dB.

[0085] 3. Adhesion performance: 1250 gf / inch peel force at 180°, with no adhesive residue after peeling.

[0086] 4. Structural stability: No slippage was observed during the 522-hour stability test; after 48 hours of PCT damp heat aging, the peel strength decreased to 1080 gf / inch, with a performance degradation rate of approximately 13.6%.

[0087] 5. Electrical insulation: Tested by a dielectric spectrometer, it maintains good electrical insulation properties and no conductive path is formed.

[0088] Performance tests in Comparative Example 3.1 show that the thermal conductivity on the vertical surface is only 1.6 W / m. K, with an interface thermal resistance as high as 35.2 K. With an electromagnetic shielding effectiveness of only 27-33 dB and a diameter of mm² / W, the ZnO network demonstrates its crucial role in enhancing thermal conductivity and electromagnetic shielding.

[0089] Performance tests in Comparative Example 3.2 show that the thermal conductivity on the vertical surface is 1.7 W / m. K, with an electromagnetic shielding effectiveness of 41-43 dB, and slight slippage observed in structural stability testing, proves that the continuous ZnO network under PEI regulation is the core of performance synergy.

[0090] Example 4 raw material: Substrate: Copper foil; Seed culture ingredients: Zn(Cl)2 (1.2 mg), KOH (0.23 mg), anhydrous ethanol (100 ml); Growth medium raw material: Zn(NO3)6 6H2O (1.1 g), HMDA (0.4 g), PEG (0.5 g), anhydrous ethanol (100 ml); AA (31 g), TDI (0.465 g), ethyl acetate (8.3 g).

[0091] Step 1: Prepare seed solution 1.2 mg Zn(Cl)2 and 0.23 mg KOH were added sequentially to 100 ml of anhydrous ethanol and stirred (300 rpm) until completely dissolved. The solution was then heated in a 65°C water bath for 45 min and allowed to cool naturally to room temperature to obtain a homogeneous and transparent seed solution.

[0092] Step 2: Preparation of seed crystal substrate The seed solution was evenly dropped onto the surface of copper foil (coating amount: 0.1 ml / cm²). 3 After coating, the copper foil is placed in an oven at 180 ℃ for annealing for 15 min. After cooling, the drop coating-annealing cycle is repeated 3 times to ensure that the copper foil surface is uniformly loaded with ZnO seeds, thus obtaining a seed crystal substrate loaded with zinc oxide ZnO seeds.

[0093] Step 3: Preparation of growth solution 1.1g Zn(NO3)6 6H2O, 0.4 g HMDA, and 0.5 g PEG were added to 100 ml of anhydrous ethanol and magnetically stirred (500 rpm) until the solid was completely dissolved. The mixture was then heated in a 95°C water bath for 30 min and cooled to 60°C to obtain a clear growth solution.

[0094] Step 4: Preparation of substrate-zinc oxide (ZnO) network The seed crystal substrate was immersed in the growth solution (the liquid level covered the substrate) and placed in a 95℃ constant temperature reaction chamber for 8 hours for hydrothermal growth. After the reaction was completed, the copper foil was removed and rinsed three times alternately with deionized water and anhydrous ethanol to remove residual impurities on the surface. Then it was dried in a 50℃ oven for 12 hours to obtain the substrate-zinc oxide ZnO network intermediate (ZnO network height approximately 10-50 μm).

[0095] Step 5: Preparation of substrate-zinc oxide (ZnO) network-acrylic acid (AA) composite material 31 g AA, 8.3 g ethyl acetate and 0.465 g TDI were mixed evenly in proportion, dispersed at high speed (400 rpm) for 10 min and then coated onto the substrate-zinc oxide ZnO network surface (coating speed 300 mm / min). After drying at 80℃ for 20 min, crosslinking and curing were completed to obtain the substrate-zinc oxide ZnO network-acrylic AA composite material.

[0096] Comparative Example 4.1 Except for skipping steps two through four of ZnO network growth and directly coating the AA mixed slurry onto the Cu foil surface, the remaining steps are the same as in Example 4 to prepare the AA / Cu foil composite material.

[0097] Comparative Example 4.2 Except for the absence of PEI in the growth solution, the remaining steps were the same as in Example 4 to prepare ZnO@AA / Cu foil composite material (ZnO is a discrete rod structure without a continuous network).

[0098] The performance of the composite material prepared in Example 4 was tested: 1. Thermal properties: In-plane thermal conductivity is 145 W / m K, the thermal conductivity of the vertical plane is 2.7 W / m K; the interfacial thermal resistance (Rc) is 1.6 K. mm² / W.

[0099] 2. Electromagnetic shielding performance: The total shielding effectiveness (SET) in the 8.3-12.4 GHz band is 59-64 dB.

[0100] 3. Adhesion performance: 180° peel force is 1520 gf / inch, and no adhesive residue remains after peeling.

[0101] 4. Structural stability: No slippage was observed during the 520-hour stability test; after 48 hours of PCT damp heat aging, the peel strength decreased to 1390 gf / inch, with a performance degradation rate of approximately 8.6%.

[0102] 5. Electrical insulation: Tested by a dielectric spectrometer, it maintains good electrical insulation properties and no conductive path is formed.

[0103] Performance tests in Comparative Example 4.1 show that the thermal conductivity on the vertical surface is only 1.6 W / m. K, with an interface thermal resistance as high as 25.8 K. With an electromagnetic shielding effectiveness of only 25-31 dB and a diameter of mm² / W, the ZnO network demonstrates its crucial role in enhancing thermal conductivity and electromagnetic shielding.

[0104] Performance tests in Comparative Example 4.2 show that the thermal conductivity on the vertical surface is 1.5 W / m. K, with an electromagnetic shielding effectiveness of 35-43 dB, showed slight slippage in the structural stability test, proving that the continuous ZnO network under PEI regulation is the core of performance synergy.

[0105] Example 5 raw material: Substrate: Al foil (standard thickness for electronic packaging); Seed liquid raw material: Zn(CH3COO)2 2H2O (1.3 mg), ammonia (0.21 mg), isopropanol (100 ml); Growth medium ingredients: Zn(SO)4 (0.8 g), HMTA (0.6 g), PVA (0.5 g), anhydrous ethanol (100 ml); AA (32 g), TDI (0.48 g), ethyl acetate (8.5 g).

[0106] Step 1: Prepare seed solution 1.3 mg Zn(CH3COO)2 2H2O and 0.21 mg ammonia were added sequentially to 100 ml of isopropanol and stirred (300 rpm) until completely dissolved. The solution was then heated in a 65°C water bath for 45 min and allowed to cool naturally to room temperature to obtain a uniform and transparent seed solution.

[0107] Step 2: Preparation of seed crystal substrate The seed solution was evenly dropped onto the surface of aluminum foil (coating amount: 0.1 ml / cm²). 3 After coating, the aluminum foil is placed in an oven at 180 ℃ for annealing for 15 min. After cooling, the drop coating-annealing cycle is repeated 3 times to ensure that the aluminum foil surface is uniformly loaded with ZnO seeds, thus obtaining a seed crystal substrate loaded with zinc oxide ZnO seeds.

[0108] Step 3: Preparation of growth solution Add 0.8 g Zn(SO)4, 0.6 g HMTA, and 0.5 g PVG to 100 ml of anhydrous ethanol, stir magnetically (500 rpm) until the solid is completely dissolved, heat in a 95°C water bath for 30 min, and cool to 60°C to obtain a clear growth solution.

[0109] Step 4: Preparation of substrate-zinc oxide (ZnO) network The seed crystal substrate was immersed in the growth solution (the liquid level covered the substrate) and placed in a 95℃ constant temperature reaction chamber for 8 hours for hydrothermal growth. After the reaction, the aluminum foil was removed and rinsed three times alternately with deionized water and anhydrous ethanol to remove residual impurities on the surface. Then it was dried in a 50℃ oven for 12 hours to obtain the substrate-zinc oxide ZnO network intermediate (ZnO network height approximately 10-50 μm).

[0110] Step 5: Preparation of substrate-zinc oxide (ZnO) network-acrylic acid (AA) composite material 32 g AA, 8.5 g ethyl acetate and 0.48 g TDI were mixed evenly in proportion, dispersed at high speed (400 rpm) for 10 min and then coated onto the substrate-zinc oxide ZnO network surface (coating speed 300 mm / min). After drying at 80℃ for 20 min, crosslinking and curing were completed to obtain the substrate-zinc oxide ZnO network-acrylic AA composite material.

[0111] Comparative Example 5.1 Except for skipping steps two through four of ZnO network growth and directly coating the AA mixed slurry onto the Al foil surface, the remaining steps are the same as in Example 5 to prepare the AA / Al foil composite material.

[0112] Comparative Example 5.2 Except for the absence of PEI in the growth solution, the remaining steps were the same as in Example 5 to prepare ZnO@AA / Al foil composite material (ZnO is a discrete rod structure without a continuous network).

[0113] The performance of the composite material prepared in Example 5 was tested: 1. Thermal properties: In-plane thermal conductivity is 140 W / m K, the thermal conductivity in the vertical plane is 2.3 W / m K; the interfacial thermal resistance (Rc) is 1.2 K. mm² / W.

[0114] 2. Electromagnetic shielding performance: The total shielding effectiveness (SET) in the 8.2-12.4GHz frequency band is 55-63 dB.

[0115] 3. Adhesion performance: 1250 gf / inch peel force at 180°, with no adhesive residue after peeling.

[0116] 4. Structural stability: No slippage was observed during the 522-hour stability test; after 48 hours of PCT damp heat aging, the peel strength decreased to 1080 gf / inch, with a performance degradation rate of approximately 13.6%.

[0117] 5. Electrical insulation: Tested by a dielectric spectrometer, it maintains good electrical insulation properties and no conductive path is formed.

[0118] Performance tests in Comparative Example 5.1 show that the thermal conductivity on the vertical surface is only 1.3 W / m. K, with an interface thermal resistance as high as 35.1 K. With an electromagnetic shielding effectiveness of only 26-31 dB and a diameter of mm² / W, the ZnO network demonstrates its crucial role in enhancing thermal conductivity and electromagnetic shielding.

[0119] Performance tests in Comparative Example 5.2 show that the thermal conductivity on the vertical surface is 1.3 W / m. K, with an electromagnetic shielding effectiveness of 37-42 dB, and slight slippage observed in structural stability tests, proves that the continuous ZnO network under PEI regulation is the core of performance synergy.

[0120] Example 6 raw material: Substrate: Passivated magnesium foil; Seed liquid ingredients: Zn(Cl)2 (1.4 mg), NaOH (0.26 mg), isopropanol (100 ml); Growth medium ingredients: Zn(SO)4 (0.75 g), HMDA (0.6 g), PVA (0.4 g), anhydrous ethanol (100 ml); AA (33 g), TDI (0.495 g), ethyl acetate (8.8 g).

[0121] Step 1: Prepare seed solution 1.4 mg Zn(Cl)2 and 0.26 mg NaOH were added sequentially to 100 ml of isopropanol and stirred (300 rpm) until completely dissolved. The solution was then heated in a 65°C water bath for 45 min and allowed to cool naturally to room temperature to obtain a homogeneous and transparent seed solution.

[0122] Step 2: Preparation of seed crystal substrate The seed solution was evenly drop-coated onto the surface of passivated magnesium foil (coating amount: 0.1 ml / cm²). 3 After coating, the passivated magnesium foil is placed in an oven at 180 ℃ for annealing for 15 min. After cooling, the drop coating-annealing cycle is repeated 3 times to ensure that the surface of the passivated magnesium foil is uniformly loaded with ZnO seeds, thus obtaining a seed crystal substrate loaded with zinc oxide ZnO seeds.

[0123] Step 3: Preparation of growth solution Add 0.75 g Zn(SO)4, 0.6 g HMDA, and 0.4 g PVA to 100 ml of anhydrous ethanol, stir magnetically (500 rpm) until the solid is completely dissolved, heat in a 95°C water bath for 30 min, and cool to 60°C to obtain a clear growth solution.

[0124] Step 4: Preparation of substrate-zinc oxide (ZnO) network The seed crystal substrate was immersed in the growth solution (the liquid level covered the substrate) and placed in a 95℃ constant temperature reaction chamber for 8 h for hydrothermal growth. After the reaction, the passivated magnesium foil was removed and rinsed three times alternately with deionized water and anhydrous ethanol to remove residual impurities on the surface. Then it was dried in a 50℃ oven for 12 h to obtain the substrate-zinc oxide ZnO network intermediate (ZnO network height approximately 10-50 μm).

[0125] Step 5: Preparation of substrate-zinc oxide (ZnO) network-acrylic acid (AA) composite material 33g AA, 8.8g ethyl acetate and 0.495g TDI were mixed evenly in proportion, dispersed at high speed (400 rpm) for 10 min, and then coated onto the substrate-zinc oxide ZnO network surface (coating speed 300 mm / min). After drying at 80℃ for 20 min, crosslinking and curing were completed to obtain the substrate-zinc oxide ZnO network-acrylic AA composite material.

[0126] Comparative Example 6.1 Except for skipping steps two through four of ZnO network growth and directly coating the AA mixed slurry onto the Al foil surface, the remaining steps are the same as in Example 6 to prepare the AA / passivated Mg foil composite material.

[0127] Comparative Example 6.2 Except for the absence of PEI in the growth solution, the remaining steps were the same as in Example 6 to prepare ZnO@AA / passivated Mg foil composite material (ZnO is a discrete rod structure without a continuous network).

[0128] The performance of the composite material prepared in Example 6 was tested: 1. Thermal properties: In-plane thermal conductivity is 135 W / m K, the thermal conductivity of the vertical plane is 2.1 W / m K; the interfacial thermal resistance (Rc) is 1.0 K. mm² / W.

[0129] 2. Electromagnetic shielding performance: The total shielding effectiveness (SET) in the 8.2-12.4GHz frequency band is 58-61 dB.

[0130] 3. Adhesion performance: 1220 gf / inch peel force at 180°, with no adhesive residue after peeling.

[0131] 4. Structural stability: No slippage was observed during the 516-hour stability test; after 48 hours of PCT damp heat aging, the peel strength decreased to 1100 gf / inch, with a performance degradation rate of approximately 9.8%.

[0132] 5. Electrical insulation: Tested by a dielectric spectrometer, it maintains good electrical insulation properties and no conductive path is formed.

[0133] Performance tests in Comparative Example 6.1 show that the thermal conductivity on the vertical surface is only 1.6 W / m. K, with an interface thermal resistance as high as 36.5 K. With an electromagnetic shielding effectiveness of only 24-33 dB and a diameter of mm² / W, the ZnO network demonstrates its crucial role in enhancing thermal conductivity and electromagnetic shielding.

[0134] Performance tests in Comparative Example 6.2 show that the thermal conductivity on the vertical surface is 1.3 W / m. K, with an electromagnetic shielding effectiveness of 33-46 dB, and slight slippage observed in structural stability tests, proves that the continuous ZnO network under PEI regulation is the core of performance synergy.

[0135] As can be seen, this application has prepared a multifunctional thermal interface composite material with high thermal conductivity, efficient electromagnetic shielding, electrical insulation, and strong adhesion through an integrated design of in-situ ZnO network growth on the substrate and AA infiltration curing. This composite material solves the defects of high interfacial thermal resistance and difficulty in synergistic performance of traditional thermal interface materials, and its in-plane thermal conductivity reaches 147 W / m. K, vertical thermal conductivity reaches 2.8 W / m K, electromagnetic shielding effectiveness ≥60 dB, peel strength ≥1250 gf / inch, interface thermal resistance as low as 1.3K With a strength of mm² / W and excellent structural stability, it can be widely used in electronic packaging scenarios such as chips, lithium-ion batteries, and flexible electronic devices, meeting the needs of multiple performance integration applications.

[0136] The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. An integrated multifunctional thermal interface composite material, characterized in that, The raw materials for the integrated multifunctional thermal interface composite material include the following components: The substrate is an aluminum foil, copper foil, or passivated magnesium foil; The seed solution is prepared in the form of anhydrous ethanol or isopropanol, and contains 1-1.5 mg of zinc salt and 0.2-0.3 mg of alkali per 100 ml of solvent. The growth solution is a solvent for anhydrous ethanol or ethylene glycol, and contains 0.5-1.5 g zinc salt, 0.2-0.8 g alkali and 0.3-0.9 g growth regulator per 100 ml of solvent. Based on 100 ml of solvent in the seed solution and 100 ml of solvent in the growth solution, the following amounts were used: AA 25-35 g, TDI 0.375-0.525 g, and EA 7-10 g.

2. The integrated multifunctional thermal interface composite material according to claim 1, characterized in that, In the seed solution, the zinc salt is selected from zinc acetate dihydrate Zn(CH3COO)2. One or more of 2H2O and zinc chloride Zn(Cl)2, and the base is selected from one or more of sodium hydroxide NaOH, potassium hydroxide KOH and ammonia water.

3. The integrated multifunctional thermal interface composite material according to claim 1, characterized in that, In the growth solution, the zinc salt is selected from zinc nitrate hexahydrate Zn(NO3)6. One or more of 6H2O and zinc sulfate (ZnSO4), the base is selected from one or more of hexamethylenetetramine (HMTA) and hexamethylenediamine (HMDA), and the growth regulator is selected from one or more of polyethyleneimine (PEI), polyethylene glycol (PEG), and polyvinyl alcohol (PVA).

4. The integrated multifunctional thermal interface composite material according to claim 1, characterized in that, The composite material meets the following performance requirements: in-plane thermal conductivity ≥140 W / m K, vertical thermal conductivity ≥ 2.5 W / m K; Electromagnetic shielding effectiveness SET≥60 dB in the 8.2-12.4 GHz band; Interface thermal resistance Rc≤1.5 K mm² / W; 180° peel force ≥1250 gf / inch; no slippage in 518 h stability test.

5. The integrated multifunctional thermal interface composite material according to claim 1, characterized in that, The integrated multifunctional thermal interface composite material is an integrated structure of substrate-zinc oxide (ZnO) network-acrylic acid (AA) composite. The zinc oxide (ZnO) network is a continuous three-dimensional network structure, and the acrylic acid (AA) permeates and fills the voids in the zinc oxide (ZnO) network.

6. A method for preparing an integrated multifunctional thermal interface composite material as described in any one of claims 1-5, characterized in that, Includes the following steps: S1. Preparation of seed crystal substrate: The seed solution is drop-coated onto the substrate surface, annealed at 178-182℃, and the drop-coating-annealing cycle is repeated 2-5 times to obtain a seed crystal substrate loaded with zinc oxide ZnO seeds. S2. Preparation of substrate-zinc oxide ZnO network: Immerse the seed crystal substrate obtained in step S1 into the growth solution, keep it at 93-97℃ for 6-10 h, wash and dry at 48-52℃ for 10-14 h to obtain substrate-zinc oxide ZnO network. S3. Preparation of substrate-zinc oxide ZnO network-acrylic acid AA composite material: Mix acrylic acid AA, toluene diisocyanate TDI and ethyl acetate EA in proportion and coat them evenly on the surface of the substrate-zinc oxide ZnO network obtained in step S2. Dry at 78-82℃ for 18-22 min to obtain substrate-zinc oxide ZnO network-acrylic acid AA composite material.

7. The preparation method according to claim 6, characterized in that, The method for preparing the seed solution in step S1 is as follows: The zinc salt and alkali were dissolved in a solvent and heated in a water bath at 63-67°C for 42-47 min to obtain the seed solution; wherein the zinc salt was selected from zinc acetate dihydrate Zn(CH3COO)2. One or more of 2H2O and zinc chloride Zn(Cl)2, and the base is selected from one or more of sodium hydroxide NaOH, potassium hydroxide KOH and ammonia water.

8. The preparation method according to claim 6, characterized in that, The preparation method of the growth solution in step S2 is as follows: Zinc salt, alkali and growth regulator are dissolved in a solvent and heated in a water bath at 93-97 ℃ for 28-32 min to obtain the growth solution; The zinc salt is selected from zinc nitrate hexahydrate Zn(NO3)6. One or more of 6H2O and zinc sulfate (ZnSO4), the base is selected from one or more of hexamethylenetetramine (HMTA) and hexamethylenediamine (HMDA), and the growth regulator is selected from one or more of polyethyleneimine (PEI), polyethylene glycol (PEG), and polyvinyl alcohol (PVA).

9. The preparation method according to claim 6, characterized in that, In step S3, the coating thickness is 18-22 μm.

10. The application of an integrated multifunctional thermal interface composite material as described in any one of claims 1-5 in electronic packaging, characterized in that, The application scenarios include one or more of the following: chip heat dissipation packaging, lithium-ion battery packaging, and thermal management of flexible electronic devices.

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