Multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material and preparation method of multilayer impedance gradient ultra-wideband terahertz composite film

Abstract

The invention belongs to the field of terahertz wave-absorbing materials, and discloses a preparation method of an impedance gradient ultra wide band terahertz composite film based on a polypyrrole material, and the preparation method comprises the following steps: dispersing linear polypyrrole in a resin master batch, and uniformly mixing to obtain a mixture; coating the mixture on a base material, and uniformly distributing the mixture through a scraper; the coated thin film is placed in a drying oven to be heated and cured to form a film; and continuously coating the spiral polypyrrole and the resin on the film layer by layer, and repeating the curing film forming process to finally obtain the resin-spiral polypyrrole-linear polypyrrole three-layer composite film. The polypyrrole composite film with ultra wide band and strong absorption is prepared through a simple and reliable process route, and the application requirements of the market for broadband absorption and thin thickness of terahertz wave-absorbing materials can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of terahertz wave absorption, and in particular relates to a multilayer impedance gradient ultra-wideband terahertz composite film based on a polypyrrole material and a preparation method thereof. Background Art

[0002] Terahertz refers to electromagnetic waves with a frequency range of 0.1-10THz. Its position on the electromagnetic spectrum is between microwaves and optical infrared. It is the transition zone from macroscopic classical theory to microscopic quantum theory, and also the transition zone from electronics to photonics. It is called the "terahertz gap" of the electromagnetic spectrum. Terahertz waves have the characteristics of high penetration, low photon energy, and wide bandwidth. As an important cross-cutting field, terahertz technology provides a very attractive opportunity for technological innovation, national economic development, and national security, and may trigger a revolutionary development of science and technology. Terahertz technology has shown broad development prospects and huge application potential in the fields of security inspection, imaging, and detection.

[0003] While paying attention to the rapid development of terahertz technology, we should not ignore the harm that terahertz radiation brings to the human body. Although the photon energy of terahertz radiation is very low, as an electromagnetic radiation, it still causes some irreversible harm to the human body. Therefore, when using terahertz technology, it should be ensured that its potential harm to the human body is minimized within a reasonable range. Absorbing materials can efficiently absorb electromagnetic waves and greatly weaken them, and ultimately convert electromagnetic waves into heat energy or other forms of energy. Therefore, the use of terahertz absorbing materials is an effective way to improve electromagnetic compatibility, reduce electromagnetic radiation, and protect human health.

[0004] Compared with traditional absorbing materials, impedance gradient absorbing materials can absorb electromagnetic waves more effectively, reduce reflection and transmission, and improve absorbing performance through continuously changing impedance design. In addition, impedance gradient absorbing materials can be optimized and designed for specific frequency bands to achieve a wider absorption frequency band and higher absorption efficiency to meet the needs of complex and changing electromagnetic environments.

[0005] In view of this characteristic, the present invention introduces a method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material. The difference in the physical and chemical properties of polypyrroles with different microscopic morphologies is used to give the composite film an impedance gradient characteristic, thereby improving the impedance matching of the composite film and enhancing the electromagnetic absorption capacity. Summary of the invention

[0006] The purpose of the present invention is to provide a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material and a preparation method thereof, which mainly utilizes the differences in the physical and chemical properties of polypyrroles with different microscopic morphologies to prepare a multilayer impedance gradient terahertz absorption film. Through reasonable structural design, the impedance matching of the film is reduced, the electromagnetic loss capacity of polypyrrole is maximized, and finally a broadband strong absorption terahertz composite film is obtained.

[0007] In order to achieve the above-mentioned invention object, the technical solution is provided as follows:

[0008] A method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material, the steps are as follows: dispersing linear polypyrrole in a resin masterbatch and mixing evenly to obtain a mixture; coating the mixture on a substrate and distributing it evenly with a scraper; placing the coated film in an oven for heating and curing to form a film; then continuing to coat spiral polypyrrole and resin on the film layer by layer, repeating the curing film-forming process, and finally obtaining a "resin-spiral polypyrrole-linear polypyrrole" three-layer composite film.

[0009] Furthermore, the mass ratio of the linear polypyrrole to the epoxy resin is 1:10-1:100.

[0010] Furthermore, the mass ratio of the linear polypyrrole to the epoxy resin is 1:30.

[0011] Furthermore, the length of the linear polypyrrole is 5 μm±500 nm, and the broadband is 100±20 nm.

[0012] Furthermore, the resin masterbatch is one or more of epoxy resin, polyimide resin, phenolic resin and unsaturated polyester resin.

[0013] Furthermore, the mass ratio of the spiral polypyrrole to the epoxy resin is 1:10-1:100.

[0014] Furthermore, the mass ratio of the spiral polypyrrole to the epoxy resin is 1:15.

[0015] Furthermore, the length of the spiral polypyrrole is 1 μm±200 nm, and the width is 100±20 nm.

[0016] Furthermore, the curing temperature is 40-100° C., and the curing time is 1-24 hours.

[0017] Furthermore, the thickness of each layer of the three-layer composite film of "resin-helical polypyrrole-linear polypyrrole" is 100-300 microns.

[0018] Compared with the prior art, the present invention has the following technical advantages:

[0019] (1) The present invention uses linear polypyrrole and spiral polypyrrole as absorbers. First, the linear polypyrrole is dispersed in a resin masterbatch and mixed evenly to obtain a mixture. The mixture is coated on a substrate and evenly distributed by a scraper. The coated film is placed in an oven for heating and curing to crosslink and cure the resin masterbatch into a film. Then, spiral polypyrrole and resin are continuously coated layer by layer on the linear polypyrrole film to form a three-layer composite film of "resin-spiral polypyrrole-linear polypyrrole". A polypyrrole composite film with ultra-wideband and strong absorption is prepared through a simple and reliable process route, which can meet the market demand for broadband absorption and thin thickness of terahertz absorbing materials.

[0020] (2) The present invention utilizes the differences in the physical and chemical properties of polypyrroles with different microscopic morphologies to prepare a multilayer impedance gradient terahertz absorption film. Through reasonable structural design, the impedance matching of the film is reduced, the electromagnetic loss capacity of polypyrrole is maximized, and finally a broadband strong absorption terahertz composite film is obtained.

[0021] (3) The absorption efficiency of the polypyrrole composite film prepared by the present invention can reach 100% in the range of 0.2-2.2 THz.

[0022] (4) The wave absorption performance of the polypyrrole composite film prepared by the present invention in the terahertz frequency band is up to 30dB.

[0023] (5) The polypyrrole composite film prepared by the present invention has a thickness of 0.5-2 mm and is suitable for use in terahertz devices with limited space.

[0024] (6) The multi-layer impedance gradient design of the present invention effectively improves the impedance matching of the film and increases the effective absorption bandwidth. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0026] Figure 1 The microscopic morphologies of the linear polypyrrole and the helical polypyrrole used in the present invention observed under a scanning electron microscope.

[0027] Figure 2 This is a real picture of the film obtained in Example 1 of the present invention.

[0028] Figure 3 The cross-sectional microscopic morphology of the film obtained in Example 2 of the present invention observed under a scanning electron microscope.

[0029] Figure 4 This is a terahertz absorption spectrum of the thin film obtained in Example 3 of the present invention. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] In order to better understand the present invention, the present invention is further described below through the following examples, but it should not be understood as limiting the present invention. Some non-essential improvements and adjustments made by technicians in this field according to the above invention content are also considered to fall within the protection scope of the present invention.

[0032] Example 1

[0033] A method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material comprises the following steps:

[0034] 6 g of linear polypyrrole (see Figure 1 ) was dispersed in 60 g of epoxy resin and mixed evenly to obtain a mixture 1.

[0035] The mixture 1 was coated on the substrate and evenly distributed by a scraper. The coated film was placed in an oven and heated at 60°C for curing to form a film after 12 hours.

[0036] 6 g of helical polypyrrole (see Figure 1 ) was dispersed in 60 g of epoxy resin and mixed evenly to obtain mixture 2.

[0037] The mixture 2 was coated on the surface of the thin film formed of linear polypyrrole, and evenly distributed by a scraper. The coated thin film was placed in an oven and heated at 60°C for curing, and a film was formed after 12 hours.

[0038] 60g of epoxy resin was further coated on the surface of the film formed by spiral polypyrrole, and the film was evenly distributed by scraper. The coated film was placed in an oven and heated at 60°C for curing. After 12 hours, a three-layer composite film of "resin-spiral polypyrrole-linear polypyrrole" was finally obtained (see Figure 2 ).

[0039] Example 2

[0040] A method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material comprises the following steps:

[0041] 4 g of linear polypyrrole was dispersed in 60 g of epoxy resin and mixed evenly to obtain a mixture 1.

[0042] The mixture 1 was coated on the substrate and evenly distributed by a scraper. The coated film was placed in an oven and heated at 60°C for curing to form a film after 12 hours.

[0043] 6 g of spiral polypyrrole was dispersed in 60 g of epoxy resin and mixed evenly to obtain a mixture 2.

[0044] The mixture 2 was coated on the surface of the thin film formed of linear polypyrrole, and evenly distributed by a scraper. The coated thin film was placed in an oven and heated at 60°C for curing, and a film was formed after 12 hours.

[0045] 60g of epoxy resin was further coated on the surface of the film formed by spiral polypyrrole, and the film was evenly distributed by scraper. The coated film was placed in an oven and heated at 60°C for curing. After 12 hours, a three-layer composite film of "resin-spiral polypyrrole-linear polypyrrole" was finally obtained. Figure 3 ,from Figure 3 It can be seen that polypyrrole has good miscibility with the substrate and forms a uniform composite film.

[0046] Example 3

[0047] A method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material comprises the following steps:

[0048] 2 g of linear polypyrrole was dispersed in 60 g of epoxy resin and mixed evenly to obtain a mixture 1.

[0049] The mixture 1 was coated on the substrate and evenly distributed by a scraper. The coated film was placed in an oven and heated at 60°C for curing to form a film after 12 hours.

[0050] 6 g of spiral polypyrrole was dispersed in 60 g of epoxy resin and mixed evenly to obtain a mixture 2.

[0051] The mixture 2 was coated on the surface of the thin film formed of linear polypyrrole, and evenly distributed by a scraper. The coated thin film was placed in an oven and heated at 60°C for curing, and a film was formed after 12 hours.

[0052] 60g of epoxy resin was further coated on the surface of the film formed by spiral polypyrrole, and the film was evenly distributed by scraper. The coated film was placed in an oven and heated at 60°C for curing. After 12 hours, a three-layer composite film of "resin-spiral polypyrrole-linear polypyrrole" was finally obtained. Figure 4 ,from Figure 4It can be seen that the multilayer impedance gradient composite film prepared by polypyrrole exhibits excellent terahertz absorption performance, and shows effective electromagnetic wave absorption performance in the entire test frequency band, and the strongest absorption performance can reach -30dB.

[0053] Example 4

[0054] A method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material comprises the following steps:

[0055] 1 g of linear polypyrrole was dispersed in 60 g of epoxy resin and mixed evenly to obtain a mixture 1.

[0056] The mixture 1 was coated on the substrate and evenly distributed by a scraper. The coated film was placed in an oven and heated at 60°C for curing to form a film after 12 hours.

[0057] 6 g of spiral polypyrrole was dispersed in 60 g of epoxy resin and mixed evenly to obtain a mixture 2.

[0058] The mixture 2 was coated on the surface of the thin film formed of linear polypyrrole, and evenly distributed by a scraper. The coated thin film was placed in an oven and heated at 60°C for curing, and a film was formed after 12 hours.

[0059] 60g of epoxy resin was further coated on the surface of the film formed by the spiral polypyrrole, and the film was evenly distributed by a scraper. The coated film was placed in an oven and heated at 60°C for curing. After 12 hours, a film was formed, and finally a three-layer composite film of "resin-spiral polypyrrole-linear polypyrrole" was obtained.

[0060] Example 5

[0061] A method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material comprises the following steps:

[0062] 6 g of linear polypyrrole was dispersed in 60 g of epoxy resin and mixed evenly to obtain a mixture 1.

[0063] The mixture 1 was coated on the substrate and evenly distributed by a scraper. The coated film was placed in an oven and heated at 60°C for curing to form a film after 12 hours.

[0064] 4 g of spiral polypyrrole was dispersed in 60 g of epoxy resin and mixed evenly to obtain a mixture 2.

[0065] The mixture 2 was coated on the surface of the thin film formed of linear polypyrrole, and evenly distributed by a scraper. The coated thin film was placed in an oven and heated at 60°C for curing, and a film was formed after 12 hours.

[0066] 60g of epoxy resin was further coated on the surface of the film formed by the spiral polypyrrole, and the film was evenly distributed by a scraper. The coated film was placed in an oven and heated at 60°C for curing. After 12 hours, a film was formed, and finally a three-layer composite film of "resin-spiral polypyrrole-linear polypyrrole" was obtained.

[0067] Example 6

[0068] A method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material comprises the following steps:

[0069] 6 g of linear polypyrrole was dispersed in 60 g of epoxy resin and mixed evenly to obtain a mixture 1.

[0070] The mixture 1 was coated on the substrate and evenly distributed by a scraper. The coated film was placed in an oven and heated at 60°C for curing to form a film after 12 hours.

[0071] 2 g of spiral polypyrrole was dispersed in 60 g of epoxy resin and mixed evenly to obtain a mixture 2.

[0072] The mixture 2 was coated on the surface of the thin film formed of linear polypyrrole, and evenly distributed by a scraper. The coated thin film was placed in an oven and heated at 60°C for curing, and a film was formed after 12 hours.

[0073] 60g of epoxy resin was further coated on the surface of the film formed by the spiral polypyrrole, and the film was evenly distributed by a scraper. The coated film was placed in an oven and heated at 60°C for curing. After 12 hours, a film was formed, and finally a three-layer composite film of "resin-spiral polypyrrole-linear polypyrrole" was obtained.

[0074] Example 7

[0075] A method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material comprises the following steps:

[0076] 6 g of linear polypyrrole was dispersed in 60 g of epoxy resin and mixed evenly to obtain a mixture 1.

[0077] The mixture 1 was coated on the substrate and evenly distributed by a scraper. The coated film was placed in an oven and heated at 60°C for curing to form a film after 12 hours.

[0078] 1 g of spiral polypyrrole was dispersed in 60 g of epoxy resin and mixed evenly to obtain a mixture 2.

[0079] The mixture 2 was coated on the surface of the thin film formed of linear polypyrrole, and evenly distributed by a scraper. The coated thin film was placed in an oven and heated at 60°C for curing, and a film was formed after 12 hours.

[0080] 60g of epoxy resin was further coated on the surface of the film formed by the spiral polypyrrole, and the film was evenly distributed by a scraper. The coated film was placed in an oven and heated at 60°C for curing. After 12 hours, a film was formed, and finally a three-layer composite film of "resin-spiral polypyrrole-linear polypyrrole" was obtained.

[0081] Finally, it should be noted that through the embodiments described in the patent of the present invention, ordinary technicians in this field can make similar changes and adjustments under the enlightenment of the present invention without violating the spirit and claims of the present invention, and such changes fall within the scope of protection of the present invention.

Claims

1. A method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material, characterized in that: The steps are as follows: disperse linear polypyrrole in a resin masterbatch and mix them evenly to obtain a mixture; apply the mixture on a substrate and distribute it evenly with a scraper; place the coated film in an oven for heating and curing to form a film; then continue to apply spiral polypyrrole and resin layer by layer on the film, repeat the curing film-forming process, and finally obtain a "resin-spiral polypyrrole-linear polypyrrole" three-layer composite film.

2. The method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material according to claim 1, characterized in that: The mass ratio of the linear polypyrrole to the epoxy resin is 1:10-1:

100.

3. The method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material according to claim 2, characterized in that: The mass ratio of the linear polypyrrole to the epoxy resin is 1:

30.

4. A method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material according to any one of claims 1 to 3, characterized in that: The length of the linear polypyrrole is 5 μm±500 nm, and the broadband is 100±20 nm.

5. The method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material according to claim 1, characterized in that: The resin masterbatch is one or more of epoxy resin, polyimide resin, phenolic resin and unsaturated polyester resin.

6. The method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material according to claim 1, characterized in that: The mass ratio of the spiral polypyrrole to the epoxy resin is 1:10-1:

100.

7. The method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material according to claim 6, characterized in that: The mass ratio of the spiral polypyrrole to the epoxy resin is 1:

15.

8. A method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material according to claim 1, 6 or 7, characterized in that: The length of the spiral polypyrrole is 1 μm±200 nm, and the width is 100±20 nm.

9. The method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material according to claim 1, characterized in that: The curing temperature is 40-100°C and the curing time is 1-24h.

10. The method for preparing a multilayer impedance gradient ultra-wideband terahertz composite film based on polypyrrole material according to claim 1, characterized in that: The thickness of each layer of the "resin-helical polypyrrole-linear polypyrrole" three-layer composite film is 100-300 microns.

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