Graphene / micro-copper pillar array composite flexible electromagnetic shielding film and preparation method thereof

Abstract

The application discloses a flexible electromagnetic shielding film with graphene / micro-copper column array composite and a preparation method thereof, and belongs to the technical field of functional material preparation, and comprises a polyimide film layer and a graphene / micro-copper column array composite layer, wherein the polyimide film layer is arranged on the outer surface of the graphene / micro-copper column array composite layer; the graphene / micro-copper column array composite layer is arranged in N layers of stacking, and N is greater than or equal to 1; each graphene / micro-copper column array composite layer comprises a polyimide surface pure copper plating layer, a micro-copper column array layer, a polyimide solution solidification layer and a polyimide surface laser-induced graphene layer. The micro-copper column super surface array layer and the laser-induced graphene layer are matched to realize impedance matching of wave absorption of the material; and since the prepared wave absorption film has a thickness in a sub-millimeter level, the film is easy to be attached to a target surface, so that the surface conformal high and low frequency wave absorption purpose is achieved, and the conformal armor function of target electromagnetic shielding is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of functional material preparation, and particularly relates to a graphene / micro-copper column array composite flexible electromagnetic shielding film and a preparation method thereof. BACKGROUND

[0002] Radar detection technology is the most common target detection means in the modern military field, and the target position is locked through the emission of electromagnetic waves. In view of the radar detection technology, the method of setting an electromagnetic wave strong absorption layer on the target surface is also the most common and effective defense technical means. At present, the principle of the electromagnetic wave absorption layer is mainly based on absorption loss and interference loss, and the improvement of the wave absorption performance of the absorption layer mainly enhances the wave absorption and reduces the electromagnetic wave reflection. On the one hand, the electromagnetic wave energy loss of the wave absorption layer needs to be improved, and on the other hand, the impedance matching of the wave absorption layer material needs to be performed for the electromagnetic wave. For the purpose of compatible high and low frequency electromagnetic wave absorption, the performance and requirements of the wave absorption layer are higher.

[0003] At present, the two-dimensional material such as graphene is added to the wave absorption layer to improve the electromagnetic wave absorption and loss performance by using the large specific surface area of the two-dimensional material. In addition, with the development of new manufacturing technologies, 3D printing technology, electrochemical additive technology and the like are applied to the manufacturing of the wave absorption layer material, the structure and form of the wave absorption layer material are flexibly adjusted and controlled, and multi-layer gradient impedance matching is realized.

[0004] For the preparation of the flexible electromagnetic shielding film, the current 3D printing technology is more likely to realize the preparation of the large structure of the rigid substrate, and cannot meet the surface conformal electromagnetic loss and absorption of the current small target equipment. In addition, the wave absorption layer material used is single, and the wave absorption bandwidth is limited. Therefore, there is an urgent need for a flexible electromagnetic shielding film suitable for the surface conformal wave absorption of the small target and a preparation method thereof in the prior art. SUMMARY

[0005] The application solves the technical problem of providing a graphene / micro-copper column array composite flexible electromagnetic shielding film and a preparation method, realizing the high and low frequency electromagnetic wave absorption and loss of the small target surface conformal effect, and achieving the purpose of small target stealth.

[0006] The graphene / micro-copper column array composite flexible electromagnetic shielding film comprises a polyimide film layer and a graphene / micro-copper column array composite layer, the polyimide film layer is arranged on the outer surface of the graphene / micro-copper column array composite layer; the graphene / micro-copper column array composite layer is arranged in N layers, and N is greater than or equal to 1; each graphene / micro-copper column array composite layer comprises a polyimide surface pure copper plating layer, a micro-copper column array layer, a polyimide solution solidification layer and a polyimide surface laser-induced graphene layer, the polyimide solution solidification layer is wrapped around the micro-copper column array layer and connected with the polyimide surface pure copper plating layer to form a micro-copper column array and polyimide composite layer; the upper surface of the micro-copper column array and polyimide composite layer is the polyimide laser-induced graphene layer.

[0007] The deposition thickness of the polyimide surface pure copper plating layer is 0.05-1 microns.

[0008] The micro-copper column height of the micro-copper column array layer is 20-50 microns.

[0009] The thickness of the polyimide solution solidification layer is 50-100 microns.

[0010] The thickness of the polyimide laser-induced graphene layer is 20-50 microns.

[0011] The preparation method of the graphene / micro-copper column array composite flexible electromagnetic shielding film comprises the following steps, and the steps are sequentially performed,

[0012] Step one: depositing a micron-level pure copper layer on a polyimide film by using a chemical vapor deposition process to obtain a polyimide surface pure copper plating layer;

[0013] Step two: printing a pure copper column array structure on the surface of the polyimide surface pure copper plating layer by using an electrochemical deposition technology to obtain a micro-copper column array layer;

[0014] Step three: spin coating a polyimide solution on the micro-copper column array by using a spin coating method, and forming a micro-copper column array and polyimide composite layer after high-temperature solidification;

[0015] Step four: scanning the micro-copper column array and polyimide composite layer obtained in step three along a predetermined track by using a laser to generate porous graphene by laser induction and form a graphene / micro-copper column array composite layer;

[0016] Step five: further repeating steps one to four on the surface of the polyimide flexible layer to form a layered graphene / micro-copper column array composite flexible electromagnetic shielding film;

[0017] Step six, covering the flexible electromagnetic shielding film surface formed in step five with a polyimide tape for encapsulation.

[0018] The step one is to deposit copper or aluminum conductive material on the polyimide film by chemical vapor deposition process.

[0019] The step two is to use a micro-additive manufacturing process based on hollow AFM probe localized electrodeposition in electrochemical deposition technology.

[0020] The step four is to use carbon dioxide laser or femtosecond laser in laser scanning, the wavelength of carbon dioxide laser is 10.6 μm, and the wavelength of femtosecond laser is 355 nm.

[0021] Through the above design scheme, the graphene / micro-copper column array composite flexible electromagnetic shielding film and the preparation method can bring the following beneficial effects: the graphene / micro-copper column array composite flexible electromagnetic shielding film and the preparation method cooperates the micro-copper column super surface array layer and the laser-induced graphene layer to realize impedance matching of material wave absorption; and since the prepared wave absorption film has a sub-millimeter thickness, it is easy to be attached to the target surface, so that the surface conformal high-frequency wave absorption purpose is achieved, and the conformal armor function of target electromagnetic shielding is realized. BRIEF DESCRIPTION OF DRAWINGS

[0022] The application will be further described below in combination with the drawings and specific embodiments:

[0023] Figure 1 It is a single-layer structure schematic diagram of the graphene / micro-copper column array composite flexible electromagnetic shielding film.

[0024] Figure 2 It is a two-layer structure schematic diagram of the graphene / micro-copper column array composite flexible electromagnetic shielding film.

[0025] Figure 3 It is a flowchart schematic diagram of the graphene / micro-copper column array composite flexible electromagnetic shielding film preparation method.

[0026] Figure 4 It is a micro-copper column array structure schematic diagram of the graphene / micro-copper column array composite flexible electromagnetic shielding film.

[0027] In the figure, 1 is a polyimide film layer, 2 is a micro-copper column array layer, 3 is a polyimide solution solidification layer, 4 is a polyimide laser-induced graphene layer, and 5 is a polyimide surface pure copper plating layer. DETAILED DESCRIPTION

[0028] The graphene / micro-copper column array composite flexible electromagnetic shielding film, as shown in the figure, includes a single-layer graphene / micro-copper column array composite flexible electromagnetic shielding film, and as shown in the figure, includes a two-layer graphene / micro-copper column array composite flexible electromagnetic shielding film. Figure 1 Figure 2 ​The flexible electromagnetic shielding film of the graphene / micro-copper pillar array composite formed by stacking is shown in the figure;

[0029] The single-layer graphene / micro-copper pillar array composite flexible electromagnetic shielding film comprises a polyimide film layer 1 and a graphene / micro-copper pillar array composite layer, the polyimide film layer 1 is arranged on the outer surface of the graphene / micro-copper pillar array composite layer; the graphene / micro-copper pillar array composite layer comprises a polyimide surface pure copper plating layer 5, a micro-copper pillar array layer 2, a polyimide solution solidification layer 3 and a polyimide surface laser-induced graphene layer 4, the polyimide solution solidification layer 3 is wrapped around the micro-copper pillar array layer 2 and connected with the polyimide surface pure copper plating layer 5 to form a micro-copper pillar array and polyimide composite layer; the upper surface of the micro-copper pillar array and polyimide composite layer is the polyimide laser-induced graphene layer 4.

[0030] The graphene / micro-copper pillar array composite layer of the flexible electromagnetic shielding film of the graphene / micro-copper pillar array composite formed by stacking is arranged in N layers, and N≥1; each graphene / micro-copper pillar array composite layer comprises a polyimide surface pure copper plating layer 5, a micro-copper pillar array layer 2, a polyimide solution solidification layer 3 and a polyimide surface laser-induced graphene layer 4, the polyimide solution solidification layer 3 is wrapped around the micro-copper pillar array layer 2 and connected with the polyimide surface pure copper plating layer 5 to form a micro-copper pillar array and polyimide composite layer; the upper surface of the micro-copper pillar array and polyimide composite layer is the polyimide laser-induced graphene layer 4.

[0031] Specifically, the thickness of the polyimide film layer 1 is 100 μm; the height of the micro-copper pillar array layer 2 is 20 μm; the thickness of the polyimide solution solidification layer 3 is 50 μm;

[0032] The preparation method of the flexible electromagnetic shielding film of the graphene / micro-copper pillar array composite comprises the following steps: Figure 3 As shown, the preparation method comprises the following steps:

[0033] Step one, depositing a 0.1 μm pure copper layer on the polyimide film by using a chemical vapor deposition process;

[0034] Step two, printing a pure copper pillar array structure on the surface of the copper layer of the polyimide film by using an electrochemical deposition technology, as shown in the figure, the structure height is 20 μm, the array length and width are 10×10 mm, and the array spacing is 50 μm; Figure 4

[0035] Step three, spinning the polyimide solution on the micro-copper pillar array by using a spin coating method, controlling the spin coating thickness to be 50 μm; then moving the sample into a temperature control box, heating to 400 ℃ for solidification to form a micro-copper pillar array and polyimide composite layer;

[0036] ​Step four, using 10.6 μm wavelength of carbon dioxide laser to scan the composite layer along the predetermined track, laser-induced porous graphene is generated, forming a graphene / micro copper column array composite polyimide flexible layer;

[0037] Step five, further repeating the above steps one to four on the surface of the polyimide flexible layer, forming a layered stack of a graphene / micro copper column array composite flexible electromagnetic shielding film, the number of stacked layers N≥1.

[0038] Step six, covering the surface of the film formed in step five with a 100 μm thick polyimide tape for packaging.

[0039] Among them, a micron-level pure copper layer is deposited on the polyimide film, but the deposited layer is not limited to copper, aluminum and other conductive materials.

[0040] The electrochemical deposition technology is a micro-additive manufacturing process based on local electro-deposition of hollow AFM probe.

[0041] Using carbon dioxide laser to scan the composite layer along the predetermined track, the wavelength is 10.6 μm, but it is not limited to carbon dioxide laser, femtosecond laser and other processing means.

Claims

1. A flexible electromagnetic shielding film of graphene / micro-copper pillar array, characterized in that: The graphene / micro-copper pillar array composite layer is N-layer stacked, and N≥1; each layer of the graphene / micro-copper pillar array composite layer comprises a polyimide surface pure copper plating layer (5), a micro-copper pillar array layer (2), a polyimide solution solidification layer (3), and a polyimide surface laser-induced graphene layer (4); the polyimide solution solidification layer (3) is wrapped around the micro-copper pillar array layer (2) and connected with the polyimide surface pure copper plating layer (5) to form a micro-copper pillar array and polyimide composite layer; and the upper surface of the micro-copper pillar array and polyimide composite layer is the polyimide laser-induced graphene layer (4). The deposition thickness of the polyimide surface pure copper plating layer (5) is 0.05 μm-1 μm.

2. The flexible electromagnetic shielding film of claim 1, wherein the graphene / microcopper pillar array composite is characterized by: The micro-copper pillar height of the micro-copper pillar array layer (2) is 20 μm-50 μm.

3. The flexible electromagnetic shielding film of claim 1, wherein the graphene / microcopper pillar array composite is characterized by: The thickness of the polyimide solution solidification layer (3) is 50 μm-100 μm.

4. The flexible electromagnetic shielding film of claim 1, wherein the graphene / microcopper pillar array composite is characterized by: The thickness of the polyimide laser-induced graphene layer (4) is 20 μm-50 μm.

5. The flexible electromagnetic shielding film of claim 1, wherein the graphene / microcopper pillar array composite is characterized by: The preparation of the graphene / micro-copper pillar array composite flexible electromagnetic shielding film as claimed in claim 1 comprises the following steps, and the steps are sequentially performed, 6. A method for preparing a flexible electromagnetic shielding film of graphene / micro-copper pillar array, characterized in that: Step one: a micron-level pure copper layer is deposited on a polyimide film by using a chemical vapor deposition process to obtain a polyimide surface pure copper plating layer (5); Step two: a pure copper pillar array structure is printed on the surface of the polyimide surface pure copper plating layer (5) by using an electrochemical deposition technology to obtain a micro-copper pillar array layer (2); Step three: a polyimide solution is spin-coated on the micro-copper pillar array by using a spin coating method, and a micro-copper pillar array and polyimide composite layer is formed after high-temperature solidification; Step four: a laser is used to scan the micro-copper pillar array and polyimide composite layer obtained in step three along a predetermined track to generate porous graphene by laser induction to form a graphene / micro-copper pillar array composite layer; Step five: the above steps one to four are further repeated on the surface of the polyimide flexible layer to form a layered stacked graphene / micro-copper pillar array composite flexible electromagnetic shielding film; Step six: a polyimide adhesive tape is covered on the surface of the flexible electromagnetic shielding film formed in step five for packaging. In step one, copper or aluminum conductive material is deposited on the polyimide film by using a chemical vapor deposition process.

7. The method for preparing the graphene / microcopper pillar array composite flexible electromagnetic shielding film according to claim 6, characterized in that: In step two, a micro-additive manufacturing process based on a hollow AFM probe localized electrodeposition is used in the electrochemical deposition technology.

8. The method of claim 6, wherein the method further comprises the steps of: providing a graphene / microcopper pillar array composite flexible electromagnetic shielding film; and coating the graphene / microcopper pillar array composite flexible electromagnetic shielding film with a polymer layer. In step four, a carbon dioxide laser or a femtosecond laser is used for laser scanning, the wavelength of the carbon dioxide laser is 10.6 μm, and the wavelength of the femtosecond laser is 355 nm.

9. The method of claim 6, wherein the method further comprises the steps of: providing a graphene / microcopper pillar array composite flexible electromagnetic shielding film; and coating the graphene / microcopper pillar array composite flexible electromagnetic shielding film with a polymer layer. ​

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