Preparation method of metamaterial with both negative dielectric response and dielectric near-zero response

Abstract

The invention discloses a preparation method of a metamaterial with negative dielectric and dielectric near-zero response, and relates to the field of electromagnetic metamaterials with negative dielectric response, in particular to a metamaterial with negative dielectric and dielectric near-zero response characteristics designed through a carbon black / polyaniline and polyaniline laminated structure. The carbon black / polyaniline laminated metamaterial has the performance characteristics that an adjustable negative dielectric constant and a dielectric near-zero effect are realized in a frequency band of 100Hz-50MHz, and the specific preparation method is as follows: the carbon black / polyaniline laminated metamaterial takes carbon black as a functional phase and polyaniline as a matrix phase, and the carbon black is randomly distributed in the polyaniline matrix by adopting a ball milling process to form a three-dimensional conductive network; according to the present invention, the carbon black / polyaniline content ratio and the lamination thickness ratio are controlled so as to change the microstructure of the metamaterial, such that the adjustable negative dielectric and the dielectric near-zero response can be achieved, and the negative dielectric response and the dielectric near-zero performance regulation and control process of the prepared lamination metamaterial is changed according to the carbon black / polyaniline mass ratio, the lamination thickness ratio, the pressing pressure, the pressing time and other conditions.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic metamaterials with negative dielectric response, and specifically to a method for preparing a metamaterial with both negative dielectric response and dielectric near-zero response. Background Art

[0002] Metamaterials are a type of artificial material system that obtains extraordinary physical properties that natural materials do not have through orderly structural design at key physical scales. In 2000, D.R. Smith et al. in the United States used metal wire arrays and periodic metal open resonant rings to construct metamaterials with negative dielectric constants and negative magnetic permeability for the first time, and manipulated the propagation path of electromagnetic waves in a specific frequency band to make the target area "invisible" in the microwave band, which stimulated a research boom in metamaterials. The "negative refractive index left-handed material" developed in 2003 and the "metamaterial invisibility cloak" developed in 2006 were rated as "the world's top ten scientific and technological breakthroughs" by Science magazine. In 2010, Science magazine selected metamaterials as one of the top ten most significant scientific and technological breakthroughs of mankind in the past decade.

[0003] The emergence of metamaterials is a major innovation in the design of material performance, and it has opened up a new path for the research and development of electromagnetic functional materials. The development of metamaterials in the electromagnetic field integrates cutting-edge technologies in multiple fields such as electronic information, mathematical statistics, biomedicine, and wireless interconnection, and has important scientific research value and engineering application potential in aerospace communications, military stealth, and wireless power transmission. In the field of aerospace communications, metamaterials can improve the directivity, tunability, and radiation power of antennas and reduce the size of antennas; in the field of military stealth, metamaterial absorbers have many advantages such as thin thickness, light weight, strong absorption, adjustable frequency band, and designable material parameters; in wireless power transmission systems, metamaterials can improve the efficiency of power transmission by focusing the magnetic field; in addition, metamaterials also show great application potential in related fields such as electromagnetic shielding, sensors, filters, and resonators.

[0004] The research on metamaterials has attracted great attention from domestic and foreign academic circles, industry, and government and military circles. The United States, Japan, the European Union and other countries and international organizations have listed metamaterials as emerging industries with national strategic significance. my country has also made the research on metamaterials one of the areas to vigorously develop. The performance of metamaterials is closely related to the structural design and characteristic design of functional units. However, the intrinsic relationship between the geometric configuration, intrinsic properties, arrangement mode and preparation process of functional units and the performance still lacks systematic theoretical support, which makes it extremely difficult to realize and regulate the performance of metamaterials. Therefore, the artificial design of the structure and characteristics of functional units has always been the core issue of metamaterial research and has important research significance.

[0005] The extraordinary electromagnetic properties of metamaterials come from the special response mechanism of artificially designed functional units under electromagnetic fields. Based on the intrinsic physical properties of materials, the research ideas on functional units can be divided into three types. The first is to use metal resonant units as "artificial atoms" to produce specific electromagnetic responses near the resonant frequency, so that the entire array structure presents extraordinary macroscopic electromagnetic parameters. On this basis, a large number of research works at home and abroad have proposed a series of new functional units such as symmetrical metal resonant ring structure, Ω-type structure, S-type structure, long-short line structure, H-type structure, π-type structure, etc. in the design of functional units. A single resonant ring structure is used to achieve negative permeability and negative dielectric constant in a specific frequency band, thereby showing negative refraction. Since then, many studies have introduced functional units of other structures into electromagnetic metamaterials to achieve dual-band and triple-band negative refraction.

[0006] In view of the fact that the metamaterials designed in current literature research and engineering applications, on the one hand, mostly use metal as the functional phase, resulting in high loss, unstable performance and other problems; on the other hand, they over-rely on artificial array structures to achieve negative dielectric properties, which puts high demands on the precision processing technology of materials and limits the application demand of metamaterials. Summary of the invention

[0007] The purpose of the present invention is to provide a method for preparing a metamaterial with both negative dielectric and dielectric near-zero response, so as to solve the problem that the metamaterials designed in the current literature research and engineering applications in the above-mentioned background technology, on the one hand, mostly use metal as the functional phase, resulting in high loss, unstable performance and other problems; on the other hand, over-reliance on artificial array structures to achieve negative dielectric properties, puts forward high requirements on the precision processing technology of materials, and limits the application demand of metamaterials.

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a method for preparing a metamaterial having both negative dielectric and dielectric near-zero response, the specific process of the preparation method is as follows:

[0009] S1, carbon black / polyaniline laminated metamaterial uses carbon black as the functional phase and polyaniline as the matrix phase;

[0010] S2, using ball milling process to randomly distribute carbon black in the polyaniline matrix to form a three-dimensional conductive network;

[0011] S3, then forming the carbon black / polyaniline layer and the pure polyaniline layer under a high pressure pressing process;

[0012] S4. Metamaterials with different negative dielectric levels and dielectric near-zero frequencies are prepared by controlling the carbon black / polyaniline content ratio, stacking thickness ratio, pressing pressure and time.

[0013] Preferably, the content ratio of carbon black in polyaniline in S1 is between 2wt% and 12wt%, and the stacking thickness ratio of carbon black / polyaniline and polyaniline is between 1 / 1 and 1 / 12.

[0014] Preferably, in S3, the pressing pressure is between 5 MPa and 10 MPa, the pressing time is between 5 min and 10 min, and the pressing temperature is between 50° C. and 100° C.

[0015] Preferably, in S4, as the carbon black mass ratio increases, the stacking thickness ratio increases, the pressing pressure increases, and the pressing time increases, the density of the prepared metamaterial increases, the magnitude of the negative dielectric constant increases, and the dielectric near-zero frequency decreases.

[0016] Preferably, in S3, a dry ball milling process is used to fully disperse the carbon black and polyaniline, and then the carbon black / polyaniline powder and the polyaniline are placed in a pressing mold respectively.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: in the method for preparing a metamaterial having both negative dielectric constant and dielectric near-zero response, when the content ratio of carbon black in polyaniline is between 2wt% and 12wt%, the stacking thickness ratio of carbon black / polyaniline and polyaniline is between 1 / 1 and 1 / 12, the pressing pressure is between 5Mpa and 10Mpa, the pressing time is between 5min and 10min, and the pressing temperature is between 50°C and 100°C, the carbon black can form a three-dimensional conductive network structure in the polyaniline. As the carbon black mass ratio increases, the stacking thickness ratio increases, the pressing pressure increases, and the pressing time increases, the density of the prepared metamaterial increases, the negative dielectric constant increases in magnitude, and the dielectric near-zero frequency decreases. The key technology of the present invention is to control the carbon black / polyaniline content ratio and the stacking thickness ratio, thereby changing the microstructure of the metamaterial, and then realizing adjustable negative dielectric and dielectric near-zero response. The negative dielectric response and dielectric near-zero performance control process of the prepared layered metamaterials is achieved by changing the carbon black / polyaniline mass ratio, layer thickness ratio, pressing pressure and time. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the negative dielectric spectrum for carbon black / polyaniline and polyaniline stack thickness ratios between 1 / 1 and 1 / 12.

[0019] Figure 2 This is the TEM image of the functional phase of nanocarbon black.

[0020] Figure 3 is the SEM image of the polyaniline matrix phase. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0022] See also Figure 1-3 , the present invention provides a technical solution: in the present invention, when the content ratio of carbon black in polyaniline is between 2wt%-12wt%, the stacking thickness ratio of carbon black / polyaniline and polyaniline is between 1 / 1-1 / 12, the pressing pressure is between 5Mpa-10 Mpa, the pressing time is between 5min-10min, and the pressing temperature is between 50℃-100℃, the carbon black can form a three-dimensional conductive network structure in the polyaniline. As the carbon black mass ratio increases, the stacking thickness ratio increases, the pressing pressure increases, and the pressing time increases, the density of the prepared metamaterial increases, the negative dielectric constant increases, and the dielectric near-zero frequency decreases. The key technology of the present invention is to control the carbon black / polyaniline content ratio and the stacking thickness ratio, thereby changing the microstructure of the metamaterial, and then realizing adjustable negative dielectric and dielectric near-zero response. The negative dielectric response and dielectric near-zero performance control process of the prepared laminated metamaterial is changed by changing the carbon black / polyaniline mass ratio, stacking thickness ratio, pressing pressure and time;

[0023] Example 1: Changing the carbon black / polyaniline mass ratio to regulate the negative dielectric and near-zero dielectric properties of metamaterials.

[0024] In the present invention, the carbon black used is nanometer-level with a particle size of about 30-50nm, the polyaniline is conductive polyaniline doped with protonic acid, and according to the content ratio of carbon black in polyaniline being between 2wt% and 12wt%, 6 groups of samples are weighed, specifically 0.02g / 0.98g, 0.04g / 0.96g, 0.06g / 0.94g, 0.08g / 0.92g, 0.1g / 0.9g, and 0.12g / 0.88g, a dry ball milling process is adopted to fully disperse the carbon black and the polyaniline, and then the carbon black / polyaniline powder and the polyaniline are successively placed in a pressing mold, and pressed for 5min at a pressure of 5Mpa, the pressing temperature is 50°C, and the sample forming diameter is 15mm.

[0025] Example 2: Changing the thickness ratio of carbon black / polyaniline and polyaniline to regulate the negative dielectric and dielectric near-zero properties of metamaterials.

[0026] In the present invention, the carbon black used is nanometer-level with a particle size of about 30-50nm, the polyaniline is conductive polyaniline doped with protonic acid, and the content ratio of carbon black in polyaniline is 2wt%, specifically 0.02g / 0.98g. Six groups of samples are weighed, and the carbon black and polyaniline are fully dispersed by a dry ball milling process. Then, the carbon black / polyaniline powder and the polyaniline are successively placed in a pressing mold, and the thickness ratio of the carbon black / polyaniline powder and the polyaniline is controlled to be 1 / 2, 1 / 4, 1 / 6, 1 / 8, 1 / 10, and 1 / 12, respectively. The samples are pressed for 5 minutes at a pressure of 5Mpa, a pressing temperature of 50°C, and a sample forming diameter of 15mm.

[0027] Example 3: Changing the lamination pressing pressure to regulate the negative dielectric and dielectric near-zero properties of metamaterials.

[0028] In the present invention, the carbon black used is nanometer-level with a particle size of about 30-50nm, the polyaniline is conductive polyaniline doped with protonic acid, and the content ratio of carbon black in polyaniline is 2wt%, specifically 0.02g / 0.98g. Six groups of samples are weighed, and the carbon black and polyaniline are fully dispersed by a dry ball milling process. Then, the carbon black / polyaniline powder and the polyaniline are placed in a pressing mold respectively, and the thickness ratio of the carbon black / polyaniline powder and the polyaniline is controlled to be 1 / 1 respectively. The samples are pressed for 5 minutes at a pressure of 5Mpa, 6Mpa, 7Mpa, 8Mpa, 9Mpa and 10Mpa respectively, and the pressing temperature is 50°C. The sample forming diameter is 15mm.

[0029] Example 4: Changing the stacking pressing time to regulate the negative dielectric and dielectric near-zero properties of metamaterials.

[0030] In the present invention, the carbon black used is nanometer-level with a particle size of about 30-50nm, the polyaniline is conductive polyaniline doped with protonic acid, and the content ratio of carbon black in polyaniline is 2wt%, specifically 0.02g / 0.98g. Six groups of samples are weighed, and the carbon black and polyaniline are fully dispersed by a dry ball milling process. Then, the carbon black / polyaniline powder and the polyaniline are successively placed in a pressing mold, and the thickness ratio of the carbon black / polyaniline powder and the polyaniline is controlled to be 1 / 1 respectively. The samples are pressed for 5min, 6min, 7min, 8min, 9min and 10min under a pressure of 5Mpa, the pressing temperature is 50°C, and the sample forming diameter is 15mm.

[0031] Example 5: Changing the lamination pressing temperature can regulate the negative dielectric and dielectric near-zero properties of metamaterials.

[0032] In the present invention, the carbon black used is nanometer-level with a particle size of about 30-50nm, the polyaniline is conductive polyaniline doped with protonic acid, and the content ratio of carbon black in polyaniline is 2wt%, specifically 0.02g / 0.98g. Six groups of samples are weighed, and the carbon black and polyaniline are fully dispersed by a dry ball milling process. Then, the carbon black / polyaniline powder and the polyaniline are successively placed in a pressing mold, and the thickness ratio of the carbon black / polyaniline powder and the polyaniline is controlled to be 1 / 1 respectively. The pressing is carried out for 5 minutes under a pressure of 5Mpa, and the pressing temperatures are 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, and the sample forming diameter is 15mm.

[0033] In summary, the negative dielectric and dielectric near-zero properties of successfully prepared metamaterials are as follows Figure 1 As shown in the figure, by changing the microstructure inside the metamaterial stack, the electronic response mechanism inside its three-dimensional conductive network is regulated, and finally both negative dielectric constant and dielectric near-zero performance are achieved. As shown in the figure, all metamaterial samples have achieved adjustable negative dielectric constant and dielectric near-zero effect in the 100 Hz-50 MHz frequency band. With the change of the stack thickness, the value of the negative dielectric constant is regulated, and its order of magnitude is 10 0 -10 5 The dielectric near-zero frequency varies around 100kHz.

[0034] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in the field. Although the embodiments of the present invention have been shown and described, it is understood by ordinary technicians in the field that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing a metamaterial having both negative dielectric and dielectric near-zero response, characterized in that: The specific process of the preparation method is as follows: S1, carbon black / polyaniline laminated metamaterial uses carbon black as the functional phase and polyaniline as the matrix phase; S2, using ball milling process to randomly distribute carbon black in the polyaniline matrix to form a three-dimensional conductive network; S3, then forming the carbon black / polyaniline layer and the pure polyaniline layer under a high pressure pressing process; S4. Metamaterials with different negative dielectric levels and dielectric near-zero frequencies are prepared by controlling the carbon black / polyaniline content ratio, stacking thickness ratio, pressing pressure and time.

2. The method for preparing a metamaterial having both negative dielectric and dielectric near-zero response according to claim 1, characterized in that: The content ratio of carbon black in polyaniline in S1 is between 2wt% and 12wt%, and the stacking thickness ratio of carbon black / polyaniline and polyaniline is between 1 / 1 and 1 / 12.

3. The method for preparing a metamaterial having both negative dielectric and dielectric near-zero response according to claim 1, characterized in that: In the S3, the pressing pressure is between 5Mpa and 10Mpa, the pressing time is between 5min and 10min, and the pressing temperature is between 50°C and 100°C.

4. The method for preparing a metamaterial having both negative dielectric and dielectric near-zero response according to claim 1, characterized in that: In S4, as the carbon black mass ratio increases, the stacking thickness ratio increases, the pressing pressure increases, and the pressing time increases, the density of the prepared metamaterial increases, the magnitude of the negative dielectric constant increases, and the dielectric near-zero frequency decreases.

5. The method for preparing a metamaterial having both negative dielectric and dielectric near-zero response according to claim 1, characterized in that: In S3, a dry ball milling process is used to fully disperse the carbon black and polyaniline, and then the carbon black / polyaniline powder and the polyaniline are placed in a pressing mold respectively.

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