Super-hydrophilic layer on surface of copper-based material, and preparation method and application thereof

Abstract

The application discloses a kind of copper-based material surface super-hydrophilic layer and preparation method thereof, the method comprises: (1) pure copper surface is polished, then polished, then washes;(2) adding ammonium halide and appropriate amount of water in low-grade alcohol solvent, and the obtained mixed solution is electrolyte;(3) the electrolyte configured is constant temperature, the pure copper after pretreatment is used as anode, cathode is inert electrode, is immersed in electrolyte, Cu (OH) 2 is generated on the surface of pure copper anode by controlling constant current or constant voltage, and is cleaned after deposition;(4) the anode pure copper with the surface of Cu (OH) 2 obtained in step (3) is obtained copper oxide super-hydrophilic layer.The application uses anodic oxidation method to prepare copper oxide super-hydrophilic layer, which is lower in cost, easy to form gradient micro-nano pore structure, has larger capillary force and better permeability, and has higher cooling medium transmission efficiency.The super-hydrophilic layer has unique three-layer micro-nano structure, good hydrophilicity, and the process is simple, easy to operate, and has high yield.

Description

Technical Field

[0001] This invention relates to the field of electrochemical surface modification technology, specifically to a superhydrophilic layer on the surface of copper-based materials, its preparation method, and its application. Background Technology

[0002] The wettability of solid surfaces is closely related to their surface physics, chemistry, and mechanics, and has been a research hotspot in multiple disciplines such as mechanical engineering, materials science, chemistry, and thermophysics in recent years. The contact angle definition is the most common and widely used method both domestically and internationally. According to the definition of the solid-liquid interface contact angle (CA), surfaces with CA > 150° are called superhydrophobic surfaces, and those with CA < 5° are called superhydrophilic surfaces. Currently, there are methods and technologies for preparing superhydrophobic copper surfaces and different superhydrophobic surface morphologies, but research on the preparation structures of superhydrophilic surfaces of copper-based materials is far less extensive than that on superhydrophobic surfaces.

[0003] In recent years, with the miniaturization, integration, and high power of electronic devices, especially the high heat flux of microelectronic devices, the reliability and safety of these devices face severe challenges. Currently, the heat dissipation problem of microelectronic devices mainly manifests in excessively high local heat flux density and the easy accumulation of heat in localized areas, leading to excessively high local temperatures and uneven temperature distribution. Therefore, there is an urgent need for high heat flux heat dissipation technologies in small-scale spaces. Existing research shows that micro / nano porous surfaces can increase the vaporization core density, enhance boiling heat transfer performance, and that micro / nano structures can effectively improve the hydrophilic properties of the surface.

[0004] Currently, most methods for preparing superhydrophilic surfaces of copper-based materials involve electroplating the cathode followed by heat treatment. However, cathode electroplating causes continuous anode wear, requiring frequent anode replacements and resulting in high costs. Furthermore, cathode methods cannot form gradient micro / nano pore structures on the surface of copper-based materials, leading to strong capillary forces and poor permeability, which reduces the transport efficiency of the cooling medium. Therefore, developing anodic methods for preparing superhydrophilic copper surfaces is of great significance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention aims to provide a superhydrophilic layer on the surface of copper-based materials, its preparation method, and its application.

[0006] To address the problems existing in the prior art, the technical solution of the present invention is as follows:

[0007] In a first aspect, the present invention provides a method for preparing a superhydrophilic layer on the surface of a copper-based material, comprising the following steps:

[0008] (1) Pretreatment of pure copper surface: After grinding the pure copper surface, polish it, and then rinse it;

[0009] (2) Electrolyte preparation: Add ammonium halide and appropriate amount of water to a low alcohol solvent. The water is selected from at least one of ultrapure water, high-purity water or deionized water. The resulting mixed solution is the electrolyte.

[0010] (3) Electrochemical deposition: Keep the electrolyte prepared in step (2) at a constant temperature, use the pure copper pretreated in step (1) as the anode and the cathode as the inert electrode, immerse it in the electrolyte, and generate Cu(OH)2 on the surface of the pure copper anode by controlling the constant current or constant voltage. After the deposition is completed, clean it.

[0011] (4) Oxidation sintering: The anodic pure copper with Cu(OH)2 surface obtained in step (3) is oxidized and sintered to obtain a copper oxide superhydrophilic layer, which is a three-layer micro-nano structure.

[0012] Preferably, in step (1), the sample is rinsed with sodium bicarbonate solution and ultrapure water.

[0013] Preferably, in step (2), the lower alcohol solvent includes at least one of ethylene glycol, isopropanol, propylene glycol, methanol, and ethanol.

[0014] Preferably, in step (2), the ammonium halide includes at least one of NH4F, NH4Cl, NH4Br, and NH4I.

[0015] Preferably, in step (2), the ammonium halide is NH4F or NH4Cl.

[0016] Preferably, in step (3), the electrolyte temperature is 25℃-85℃, the constant voltage is 20V-40V, the constant current is 0.1A-1A, and the deposition time is 20min-90min.

[0017] Preferably, in step (4), the sintering temperature is 200℃-700℃, and the oxidation sintering is a segmented heating sintering with a heating rate of 5-10℃ / min.

[0018] Preferably, in step (4), the three-layer micro / nano structure of the copper oxide superhydrophilic layer consists of a copper oxide particle layer with a particle size of 2-10 μm, a copper nanowire layer with a diameter of 10-50 nm, and a copper oxide particle layer with a particle size of 10-50 nm, from the inside to the outside.

[0019] Secondly, the present invention provides a superhydrophilic layer on the surface of a copper-based material, which is prepared by the above-described preparation method.

[0020] Thirdly, the present invention provides the application of a superhydrophilic layer on the surface of a copper-based material in electronic devices.

[0021] The beneficial effects of the present invention include at least the following:

[0022] In the method for preparing the superhydrophilic layer on the surface of the copper-based material of the present invention, the copper oxide superhydrophilic layer is prepared by anodic oxidation. As the electrochemical reaction proceeds, the Cu in the electrolyte... 2+ As the concentration decreases, the morphology of Cu(OH)2 deposited on the anode surface changes. After heat treatment at a certain temperature, the resulting superhydrophilic layer has a special three-layer micro-nano structure. The three-layer micro-nano structure consists of a micron-sized copper oxide particle layer, a nano-sized copper oxide wire layer, and a nano-sized copper oxide particle layer from the inside out. It has good hydrophilicity and the minimum contact angle can reach 0°.

[0023] Moreover, the method for preparing a superhydrophilic layer on the surface of copper-based materials according to the present invention has lower cost, and the superhydrophilic layer obtained has a special three-layer micro-nano structure that can form a gradient micro-nano pore structure. It has both large capillary force and good permeability, thereby making the cooling working fluid transport efficiency higher. It also has the advantages of simple process, convenient operation and high yield.

[0024] The superhydrophilic layer on the surface of copper-based materials and its preparation method of the present invention have wide application value, especially the application of the superhydrophilic layer on the surface of copper-based materials in electronic devices (including microelectronic devices).

[0025] The features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0026] Figure 1 This is a SEM image of the superhydrophilic surface structure obtained after the process in Example 1.

[0027] Figure 2 This is a SEM image of the superhydrophilic surface structure obtained after the process in Example 2.

[0028] Figure 3 This is a SEM image of the superhydrophilic surface structure obtained after the process in Example 3.

[0029] Figure 4 This is a SEM image of the superhydrophilic surface structure obtained after the process in Example 4.

[0030] Figure 5 This is a test diagram of the contact angle of a water droplet on a superhydrophilic layer on a pure copper surface.

[0031] Figure 6 EDS image of the superhydrophilic layer on the surface of copper-based material. Detailed Implementation

[0032] To make the objectives, technical solutions, and beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Examples of the embodiments are shown in the accompanying drawings. It should be understood that the specific embodiments described in the following embodiments of the invention are merely illustrative examples of specific implementations of the invention and are intended to explain the invention, but do not constitute a limitation thereof.

[0033] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In the description of this application, unless otherwise stated, the terms "multiple / a variety" and similar terms mean two / a kind or more. Furthermore, the terms "comprising," "including," and any variations thereof are intended to cover non-exclusive inclusion.

[0034] In a first aspect, the present invention provides a method for preparing a superhydrophilic layer on the surface of a copper-based material, comprising the following steps:

[0035] (1) Pretreatment of pure copper surface: After grinding the pure copper surface, polish it, and then rinse it;

[0036] (2) Electrolyte preparation: Add ammonium halide and appropriate amount of water to a low alcohol solvent. The water is selected from at least one of ultrapure water, high-purity water or deionized water. The resulting mixed solution is the electrolyte.

[0037] (3) Electrochemical deposition: Keep the electrolyte prepared in step (2) at a constant temperature, use the pure copper pretreated in step (1) as the anode and the cathode as the inert electrode, immerse it in the electrolyte, and generate Cu(OH)2 on the surface of the pure copper anode by controlling the constant current or constant voltage. After the deposition is completed, clean it.

[0038] (4) Oxidation sintering: The anodic pure copper with Cu(OH)2 surface obtained in step (3) is oxidized and sintered to obtain a copper oxide superhydrophilic layer, which is a three-layer micro-nano structure.

[0039] In this invention, copper-based materials refer to materials with a copper content of 99.5% or more, such as pure copper.

[0040] In this invention, the method of polishing the pure copper surface in step (1) can be widely selected, and the surface roughness can reach Ra 0.025-0.05. Preferably, sandpaper is used for polishing in step (1).

[0041] In this invention, the polishing method for the pure copper surface in step (1) can be widely selected, and the polishing level can reach polishing level 4 (bright surface, with outlines clearly visible). Preferably, chemical polishing is used, and the polishing agent can be HNO3, H3PO4, or a mixture thereof, with a mass concentration of 10%-60%.

[0042] In this invention, the rinsing method in step (1) can be widely selected, and the degree of rinsing can reach a residual ionic contaminant content ≤5.0 μg / cm³. 2 Either is acceptable. Preferably, in step (1), the sample is first rinsed with a solution of sodium bicarbonate, potassium bicarbonate, or ammonium bicarbonate, and then rinsed with water. More preferably, the water is ultrapure water, high-purity water, or deionized water. Most preferably, rinsing with sodium bicarbonate solution and ultrapure water in sequence can quickly achieve a residual ionic contaminant content ≤5.0 μg / cm2, and is more conducive to subsequent electrochemical reactions.

[0043] In this invention, the choice of lower alcohol solvent in step (2) can be quite broad. In some preferred embodiments, the lower alcohol solvent in step (2) includes at least one of ethylene glycol, isopropanol, propylene glycol, methanol, and ethanol.

[0044] In this invention, the ammonium halide in step (2) can be of a wide variety. In some preferred embodiments, in step (2), the ammonium halide includes at least one of NH4F, NH4Cl, NH4Br, and NH4I. In some more preferred embodiments, in step (2), the ammonium halide is NH4F or NH4Cl.

[0045] In this invention, the final concentration of ammonium halide in the electrolyte during step (2) is 1%-5%. Preferably, the final concentration of ammonium halide in the electrolyte during step (2) is 2%-3%.

[0046] In this invention, the method of achieving constant temperature in step (3) can be selected from a wide range, such as a water bath.

[0047] In this invention, the temperature range in step (3) can be selected within a wide range, for example, 25℃-90℃. In some preferred embodiments of this invention, the electrolyte temperature in step (3) is 30℃-80℃, the constant voltage is 20V-40V, the constant current is 0.1A-1A, and the deposition time is 20min-80min. In some more preferred embodiments of this invention, the electrolyte temperature in step (3) is 50℃-80℃, the constant voltage is 30V-40V, the constant current is 0.15A-1A, and the deposition time is 40min-80min.

[0048] In this invention, the cathode is an inert electrode, such as a platinum electrode or a graphite electrode.

[0049] In this invention, the heating method for oxidation sintering can be selected from a wide range, such as heating in a muffle furnace.

[0050] In this invention, the sintering temperature of the oxidation sintering can be selected within a wide range, as long as the Cu(OH)2 generated on the surface of the pure copper anode is completely converted into copper oxide. Generally, the lower the heat treatment temperature, the easier it is to form nanoparticles; the higher the temperature, the larger the grains will be. When the temperature is high, reaching 700℃ or even higher, the size of the surface hydrophilic layer particles will increase to the micrometer level. Therefore, if a three-layer micro / nano structure is to be formed, the heat treatment temperature should not be too low or too high. Preferably, the sintering temperature is 200℃-700℃. More preferably, the sintering temperature is 400℃-600℃. Preferably, in step (4), the oxidation sintering is a segmented heating sintering with a heating rate of 5-10℃ / min.

[0051] In this invention, the three-layer micro / nano structure of the copper oxide superhydrophilic layer consists of a micron-sized copper oxide particle layer, a copper oxide nanowire layer, and a nano-sized copper oxide particle layer from the inside out.

[0052] Preferably, in step (4), the three-layer micro / nano structure of the copper oxide superhydrophilic layer consists of a first copper particle layer with a copper oxide particle diameter of 2-10 μm, a copper oxide nanowire layer with a diameter of 10-50 nm, and a second copper particle layer with a copper oxide particle diameter of 10-50 nm, from the inside to the outside.

[0053] Secondly, the present invention provides a superhydrophilic layer on the surface of a copper-based material, which is prepared by the above-described preparation method.

[0054] Thirdly, the present invention provides the application of a superhydrophilic layer on the surface of a copper-based material in electronic devices.

[0055] The present invention will be described in detail below through examples. In the following examples, all chemicals are commercially available products.

[0056] Example 1

[0057] A method for preparing a superhydrophilic layer on the surface of a copper-based material includes the following steps:

[0058] (1) Pretreatment of pure copper surface: After polishing the pure copper surface with sandpaper, it is chemically polished with polishing agent, and then rinsed with sodium bicarbonate solution and ultrapure water in sequence.

[0059] (2) Electrolyte preparation: Add 5g NH4F and 5ml ultrapure water to 150ml ethylene glycol, and use the resulting ethylene glycol and NH4F mixed solution as the electrolyte.

[0060] (3) Electrochemical deposition: The electrolyte prepared in step (2) is kept at a constant temperature of 50°C. The pure copper pretreated in step (1) is used as the anode of the electrochemical reaction and the cathode is a platinum electrode. The electrode is immersed in the electrolyte, the constant voltage is 30V, the deposition time is 30min, and the electrode is washed with ultrapure water after deposition.

[0061] (4) Oxidation sintering: The anodic pure copper with Cu(OH)2 surface obtained in step (3) is placed in a muffle furnace for oxidation sintering. After 40 minutes, the furnace temperature is raised from room temperature to 400℃, held at 400℃ for 2 hours, and then cooled to 200℃ with the furnace. Finally, the sample is taken out and allowed to cool naturally in the air to obtain a copper oxide superhydrophilic layer.

[0062] Example 2

[0063] A method for preparing a superhydrophilic layer on the surface of a copper-based material includes the following steps:

[0064] (1) Pretreatment of pure copper surface: After polishing the pure copper surface with sandpaper, it is chemically polished with polishing agent, and then rinsed with sodium bicarbonate solution and ultrapure water in sequence.

[0065] (2) Electrolyte preparation: Add 10g NH4Cl and 10ml ultrapure water to 300ml ethylene glycol, and use the resulting ethylene glycol and NH4Cl mixed solution as the electrolyte.

[0066] (3) Electrochemical deposition: The electrolyte prepared in step (2) is kept at a constant temperature of 50°C. The pure copper pretreated in step (1) is used as the anode of the electrochemical reaction and the cathode is a platinum electrode. The electrode is immersed in the electrolyte, the constant voltage is 30V, the deposition time is 80min, and the electrode is washed with ultrapure water after deposition.

[0067] (4) Oxidation sintering: The anodic pure copper with Cu(OH)2 surface obtained in step (3) is placed in a muffle furnace for oxidation sintering. After 40 minutes, the furnace temperature is raised from room temperature to 450°C and held at 450°C for 2 hours. Then, the furnace is cooled to 200°C. Finally, the sample is taken out and allowed to cool naturally in the air to obtain a copper oxide superhydrophilic layer.

[0068] Example 3

[0069] A method for preparing a superhydrophilic layer on the surface of a copper-based material includes the following steps:

[0070] (1) Pretreatment of pure copper surface: After polishing the pure copper surface with sandpaper, it is chemically polished with polishing agent, and then rinsed with sodium bicarbonate solution and ultrapure water in sequence.

[0071] (2) Electrolyte preparation: Add 9g NH4Br and 10ml ultrapure water to 300ml propylene glycol, and use the resulting propylene glycol and NH4Br mixed solution as the electrolyte.

[0072] (3) Electrochemical deposition: The electrolyte prepared in step (2) is kept at a constant temperature of 50°C. The pure copper pretreated in step (1) is used as the anode of the electrochemical reaction and the cathode is a platinum electrode. The electrode is immersed in the electrolyte with a constant current of 0.15A and a deposition time of 40min. After deposition, the electrode is washed with ultrapure water.

[0073] (4) Oxidation sintering: The anodic pure copper with Cu(OH)2 surface obtained in step (3) is placed in a muffle furnace for oxidation sintering. After 40 minutes, the furnace temperature is raised from room temperature to 500℃, held at 500℃ for 2 hours, and then cooled to 200℃ with the furnace. Finally, the sample is taken out and allowed to cool naturally in the air. A three-layer structured copper oxide superhydrophilic surface is obtained.

[0074] Example 4

[0075] A method for preparing a superhydrophilic layer on the surface of a copper-based material includes the following steps:

[0076] (1) Pretreatment of pure copper surface: After polishing the pure copper surface with sandpaper, it is chemically polished with polishing agent, and then rinsed with sodium bicarbonate solution and ultrapure water in sequence.

[0077] (2) Electrolyte preparation: Add 5g NH4F and 5ml ultrapure water to 150ml ethylene glycol, and use the resulting ethylene glycol and NH4F mixed solution as the electrolyte.

[0078] (3) Electrochemical deposition: The electrolyte prepared in step (2) is kept at a constant temperature of 50°C. The pure copper pretreated in step (1) is used as the anode of the electrochemical reaction and the cathode is a platinum electrode. The electrodes are immersed in the electrolyte, the constant voltage is 30V, the deposition time is 40min, and the electrodes are washed with ultrapure water after deposition.

[0079] (4) Oxidation sintering: The pure copper with Cu(OH)2 surface obtained in step (3) is placed in a muffle furnace for oxidation sintering. After 20 minutes, the furnace temperature is raised from room temperature to 600℃, held at 600℃ for 1 hour, and then cooled to 200℃ with the furnace. Finally, the sample is taken out and allowed to cool naturally in the air to obtain a copper oxide superhydrophilic layer.

[0080] Test Example 1: SEM Testing of Superhydrophilic Layers on Copper-Based Material Surfaces

[0081] The copper oxide superhydrophilic layers prepared in Examples 1-4 were subjected to SEM testing. The SEM testing conditions included: using secondary electrons and a test voltage of 15 kV. The SEM testing conditions were the same for all examples, and the results were obtained accordingly. Figure 1-4 .

[0082] Among them, from Figure 1As can be seen, the three-layer micro / nano structure of the copper oxide superhydrophilic layer in Example 1 consists of a copper oxide particle layer with a particle size of 2-10 μm, a copper oxide nanowire layer with a diameter of 10-50 nm, and another copper oxide particle layer with a particle size of 10-50 nm, from the inside out. In the three-layer micro / nano porous structure, the bottom layer has larger pores, at the micrometer level; the middle and top layers have smaller pores, at the nanometer level. The characteristic of this structure is that the bottom layer has larger pores, while the middle and top layers have smaller pores. This structure gives it both greater capillary force and permeability, resulting in high cooling fluid transport efficiency and a small contact angle.

[0083] Test Example 2: Contact Angle Test of Superhydrophilic Layer on Copper-Based Material Surface (Example 1)

[0084] The copper oxide superhydrophilic layer prepared in Example 1 was subjected to contact angle testing. The contact angle testing conditions included: a shooting speed of 200 frames / s and a test droplet volume of 3 μl. Figure 5 The test droplet contacted the superhydrophilic layer surface in 0.93s, spread out in 0.05s, and had a contact angle of 0° in 0.98s, showing very good hydrophilicity.

[0085] Test Example 3: EDS Test of Superhydrophilic Layer on Copper-Based Material Surface

[0086] The superhydrophilic layer prepared in Example 4 was subjected to EDS testing. The EDS testing conditions included: a test voltage of 15 kV and a surface scan time of 5 min. Figure 6 .

[0087] Depend on Figure 6 It is known that the elements on the surface of the superhydrophilic layer include Cu and O, with an atomic ratio of Cu to O of approximately 1:1, and the chemical composition of the superhydrophilic layer is CuO.

[0088] In the method for preparing the superhydrophilic layer on the surface of the copper-based material of the present invention, the copper oxide superhydrophilic layer is prepared by anodic oxidation. As the electrochemical reaction proceeds, the Cu in the electrolyte... 2+ As the concentration decreases, the morphology of Cu(OH)2 deposited on the anode surface changes. After heat treatment at a certain temperature, the resulting superhydrophilic layer has a special three-layer micro-nano structure. The three-layer micro-nano structure consists of a micron-sized copper oxide particle layer, a nano-sized copper oxide wire layer, and a nano-sized copper oxide particle layer from the inside out. It has good hydrophilicity and the minimum contact angle can reach 0°.

[0089] Moreover, the method for preparing a superhydrophilic layer on the surface of copper-based materials according to the present invention has lower cost, and the superhydrophilic layer obtained has a special three-layer micro-nano structure that can form a gradient micro-nano pore structure. It has both large capillary force and good permeability, thereby making the cooling working fluid transport efficiency higher. It also has the advantages of simple process, convenient operation, and high yield (reaching more than 95%).

[0090] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and do not constitute a limitation on the content of the present invention. Although the present invention has been described in detail through the above embodiments, those skilled in the art can still make various changes in form and detail based on the technical content described in the Summary of the Invention and the Embodiments, without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

1. A method for preparing a superhydrophilic layer on the surface of a copper-based material, characterized in that, Includes the following steps: (1) Pretreatment of pure copper surface: The pure copper surface is ground, polished, and then rinsed; the grinding achieves a surface roughness Ra of 0.025-0.05; the polishing achieves polishing level 4; the rinsing achieves a residual ionic contaminant content of ≤5.0 μg / cm²; rinsed with sodium bicarbonate solution and ultrapure water; (2) Electrolyte preparation: Add ammonium halide and appropriate amount of water to a low alcohol solvent. The water is selected from at least one of ultrapure water, high-purity water or deionized water. The resulting mixed solution is the electrolyte. The final concentration of ammonium halide in the electrolyte is 1%-5%. (3) Electrochemical deposition: The electrolyte prepared in step (2) is kept at a constant temperature. The pure copper pretreated in step (1) is used as the anode and the cathode is an inert electrode. It is immersed in the electrolyte. Cu(OH)2 is generated on the surface of the pure copper anode by controlling the constant current or constant voltage. After deposition, it is cleaned. The electrolyte temperature is 50℃-80℃, the constant voltage is 30V-40V, the constant current is 0.15A-1A, and the deposition time is 40min-80min. (4) Oxidation sintering: The anodic pure copper with Cu(OH)2 surface obtained in step (3) is oxidized and sintered to obtain a copper oxide superhydrophilic layer. The copper oxide superhydrophilic layer is a three-layer micro-nano structure. The sintering temperature of the oxidation sintering is 400℃-600℃. The oxidation sintering is a segmented heating sintering with a heating rate of 5-10℃ / min. The three-layer micro-nano structure of the copper oxide superhydrophilic layer consists of a copper oxide particle layer with a particle size of 2-10μm, a copper oxide nanowire layer with a diameter of 10-50nm, and a copper oxide particle layer with a particle size of 10-50nm, from the inside to the outside.

2. The method for preparing a superhydrophilic layer on the surface of a copper-based material according to claim 1, characterized in that, In step (2), the lower alcohol solvent includes at least one of ethylene glycol, isopropanol, propylene glycol, methanol, ethanol, etc.

3. The method for preparing a superhydrophilic layer on the surface of a copper-based material according to claim 1, characterized in that, In step (2), the ammonium halide includes at least one of NH4F, NH4Cl, NH4Br, and NH4I.

4. The method for preparing a superhydrophilic layer on the surface of a copper-based material according to claim 3, characterized in that, In step (2), the ammonium halide is NH4F or NH4Cl.

5. A superhydrophilic layer on the surface of a copper-based material, characterized in that, It is prepared by any one of the preparation methods described in claims 1-4.

6. The application of the superhydrophilic layer on the surface of the copper-based material according to claim 5 in electronic devices.

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