CN111132532B - Electromagnetic shielding material based on metal nanowires and preparation method thereof - Google Patents
Electromagnetic shielding material based on metal nanowires and preparation method thereof Download PDFInfo
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- CN111132532B CN111132532B CN201911159331.9A CN201911159331A CN111132532B CN 111132532 B CN111132532 B CN 111132532B CN 201911159331 A CN201911159331 A CN 201911159331A CN 111132532 B CN111132532 B CN 111132532B
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- H05K9/0086—Electromagnetic shielding materials, e.g. EMI, RFI shielding comprising a single discontinuous metallic layer on an electrically insulating supporting structure, e.g. metal grid, perforated metal foil, film, aggregated flakes, sintering
Abstract
The invention relates to an electromagnetic shielding material based on metal nanowires and a preparation method thereof. The electromagnetic shielding material includes: the substrate is a flexible material with a micro-skeleton structure; the metal nano network is formed on the surface of the substrate and comprises metal nano wires which are mutually lapped. The method for preparing the electromagnetic shielding material comprises the following steps: dissolving a hydrophobic high molecular polymer in a first alcohol solvent so as to obtain a hydrophobic high molecular polymer alcohol solution; dispersing the metal nanowires in a second alcohol solvent to obtain a metal nanowire alcohol dispersion; mixing the hydrophobic high-molecular polymer alcohol solution and the metal nanowire alcohol dispersion liquid, and stirring to obtain slurry; the substrate is soaked in the slurry and dried. The electromagnetic shielding material has excellent electromagnetic shielding performance, light weight, unlimited product size and adjustable electromagnetic performance; the preparation method is simple, the process is mild, the processing is rapid, and the price is low.
Description
Technical Field
The invention belongs to the technical field of material science and engineering, and particularly relates to an electromagnetic shielding material based on metal nanowires and a preparation method thereof.
Background
Due to the demand for precise control of electromagnetic waves in the fields of advanced science and technology, modern military and the like, more and more electromagnetic shielding materials are assembled on high-end electronic equipment and military equipment. The electromagnetic shielding mainly has two mechanisms of reflection and absorption, and the metal has strong reflection effect on electromagnetic waves, so the metal is a good electromagnetic shielding material. At present, in many large-scale practical applications, the electromagnetic shielding material is still in a stage of using a metal fabric woven by metal wires. This results in an electromagnetic shielding material with too high a weight, which results in the material losing its intended flexibility; and is easily damaged, resulting in lack of stability of the material, which all pose a great obstacle to practical application.
In the field of electromagnetic shielding, scientists are all working on solving the problems of light weight and stability, and compared with fabrics woven by metal wires, electromagnetic shielding materials which are lighter and more stable emerge continuously. But the distance between the light-weight and stable materials which can be practically applied is a certain distance. More importantly, the preparation of the materials usually requires the techniques of freeze drying, hydrothermal reaction and the like, which fundamentally determines that the materials can only stay in the preparation scale of laboratory grade and cannot be produced in large scale, so that the materials do not have the value of practical application.
In summary, there is an increasing demand for electromagnetic shielding materials that are lightweight, stable, and capable of mass production, but the materials need to be optimized.
Disclosure of Invention
The present invention is directed to solving, at least to some extent, one of the technical problems in the related art. In order to develop an electromagnetic shielding material more suitable for large-scale application, it is required to further reduce the density of the material and enhance the stability thereof while minimizing the amount of metal nanowires, such as silver; and the process for producing the electromagnetic shielding material is milder, more operable and expandable and cheaper. Therefore, an object of the present invention is to provide an electromagnetic shielding material and a method for preparing the same.
The inventor finds out in the research process that: the flexible material with a micro-skeleton structure can be used as a substrate, the metal nano-network is formed on the surface of the substrate, and the formed electromagnetic shielding material is covered with the metal nano-network in a three-dimensional space, so that the electromagnetic shielding material has good electromagnetic shielding performance; and the size of the product is not limited, and the electromagnetic performance is adjustable. And soaking the substrate in an alcoholic solution of the metal nanowires and an alcoholic solution of the hydrophobic high molecular polymer, and drying to obtain the electromagnetic shielding material. The method has the advantages of simple process, continuous production, mild process, quick forming and low cost, and has obvious advantages compared with the traditional metal wire weaving technology.
Specifically, the invention provides the following technical scheme:
in a first aspect of the present invention, there is provided an electromagnetic shielding material comprising: the substrate is a flexible material with a micro-skeleton structure; and a metal nano network formed on a surface of the substrate, the metal nano network including metal nanowires that are overlapped with each other.
The inventor finds that the flexible material with the micro-skeleton structure is used as the substrate, and the metal nano network formed by lapping the metal nanowires is formed on the surface of the substrate, so that the substrate has the electromagnetic shielding function. And the substrate is a flexible material with a micro-skeleton structure, so that the electromagnetic shielding material has an electromagnetic shielding function in the whole three-dimensional space and has excellent electromagnetic shielding performance. And has the advantages of light weight, unlimited product size, adjustable electromagnetic performance and the like.
According to an embodiment of the present invention, the electromagnetic shielding material described above may further include the following technical features:
in some embodiments of the invention, the substrate is at least one of a porous sponge or a fibrous fabric. For example, porous sponge or cloth can be used as a substrate, so that the obtained electromagnetic shielding material has beneficial electromagnetic shielding performance in three-dimensional space, and has various advantages of light weight, unlimited size and the like.
In some embodiments of the invention, the diameter of the microarchitectures of the substrate range from 10 microns to 100 microns.
In some embodiments of the present invention, the thickness of the metal nano-network on the surface of the substrate is 1 to 5 μm. Therefore, the electromagnetic shielding material has excellent electromagnetic shielding performance.
In some embodiments of the present invention, the metal nanowire is a one-dimensional metal nanowire, preferably at least one selected from gold, silver, copper, and nickel.
In some embodiments of the present invention, the metal nanowires have a diameter size of 50-200 nm.
In some embodiments of the present invention, the metal nano-network is formed on the surface of the substrate by a hydrophobic high molecular polymer.
In some embodiments of the present invention, the hydrophobic polymer comprises at least one selected from the group consisting of polyvinyl butyral (PVB), polymethyl methacrylate, polyvinylidene fluoride, and polyurethane. The hydrophobic high molecular polymers have good alcohol-soluble characteristics, have excellent chemical stability and special hydrophobicity compared with other binders such as PVP (polyvinylpyrrolidone), are soaked in the slurry containing the alcoholic solution of the hydrophobic high molecular polymers, so that the metal nanowires are mutually overlapped, a metal nano network is formed on the surface of the substrate, and the slurry shows good chemical stability and environmental tolerance when being applied to various flexible substrates. The electromagnetic shielding material thus provided has an excellent electromagnetic shielding function.
In some embodiments of the present invention, the substrate is soaked in a slurry containing an alcohol solution of a hydrophobic high molecular polymer and a dispersion of metal nanowire alcohol, so as to form the metal nano network on the surface of the substrate; the hydrophobic high molecular polymer alcoholic solution is an alcoholic solution containing a hydrophobic high molecular polymer, and the metal nanowire alcoholic dispersion liquid is an alcoholic solution containing the metal nanowires. The slurry is obtained by mixing the hydrophobic high-molecular polymer alcohol solution and the metal nanowire alcohol dispersion liquid, and is applied to various flexible substrates with a micro-skeleton structure, and the hydrophobic high-molecular polymer is used as an adhesive and can effectively adhere the metal nanowires on the surface of the micro-skeleton of the flexible substrate, so that the electromagnetic shielding material has an excellent electromagnetic shielding function.
In some embodiments of the present invention, the hydrophobic polymer alcohol solution is an ethanol solution containing a hydrophobic polymer, and the metal nanowire fractional solution is an ethanol solution containing the metal nanowires. The hydrophobic high molecular polymer powder can be quickly dissolved by using the ethanol to obtain a uniform ethanol solution of the hydrophobic high molecular polymer, and compared with other solvents such as acetone, the ethanol solution has no toxic or side effect and meets the requirements of environmental protection.
In some embodiments of the invention, the mass ratio of the hydrophobic high molecular polymer alcohol solution to the metal nanowire alcohol dispersion is 5:1 to 20:1, and preferably 5:1 to 15: 1. The hydrophobic high molecular polymer is used as a binder and a protective agent, so that the metal nanowires can be lapped on the surface of the substrate to form a metal nano network. When the proportion of the hydrophobic high polymer is increased, the strength and stability of the formed electromagnetic shielding material can be improved, and accordingly, the softness and the electromagnetic shielding performance of the electromagnetic shielding material are also correspondingly reduced. When the mass ratio of the alcoholic solution of the hydrophobic high-molecular polymer to the alcoholic dispersion of the metal nanowires is 5: 1-20: 1, preferably 5: 1-15: 1, the obtained slurry is stable and has certain strength, when the slurry is applied to soaking of a substrate, the flexibility of the substrate is not affected, and the obtained electromagnetic shielding material has good electromagnetic shielding performance.
In some embodiments of the present invention, the mass percentage of the hydrophobic polymer in the hydrophobic polymer alcohol solution is 0.5% to 2%. Herein, the mass percentage refers to the mass percentage of a certain substance in the total mass, and specifically refers to the mass percentage of the hydrophobic polymer in the hydrophobic polymer alcohol solution (solution containing the hydrophobic polymer and the solvent alcohol). The inventor finds that at the mass percentage, the obtained slurry has good bonding force and softness when being used for soaking a flexible substrate.
In some embodiments of the present invention, the concentration of the metal nanowires in the metal nanowire alcohol dispersion is 5 to 20 mg/mL. Thereby, the electromagnetic shielding performance of the electromagnetic shielding material can be improved.
According to a second aspect of the present invention, there is provided a method of producing an electromagnetic shielding material according to any one of the embodiments of the first aspect of the present invention, the method comprising: adding the hydrophobic high molecular polymer solution into a first alcohol solvent so as to obtain a hydrophobic high molecular polymer alcohol solution; dispersing the metal nanowires in a second alcohol solvent to obtain a metal nanowire alcohol dispersion; mixing the hydrophobic high molecular polymer alcohol solution and the metal nanowire alcohol dispersion liquid, and stirring to obtain slurry; and soaking a substrate in the slurry, and drying to obtain the electromagnetic shielding material. The method for preparing the electromagnetic shielding material has the advantages of simple process, continuous production, mild process, quick forming and low price of the used raw materials, and compared with the traditional metal wire weaving technology, the method has obvious advantages.
In some embodiments of the present invention, the hydrophobic polymer is dissolved in the first alcohol solution at 30 to 90 degrees celsius, for example, at 70 to 90 degrees celsius, preferably at 80 degrees celsius. At the temperature, when the hydrophobic high molecular polymer powder is dissolved in an alcohol solvent, for example, ethanol, the solution can be accelerated by stirring, for example, the uniform ethanol solution of the hydrophobic high molecular polymer can be obtained by stirring for 1 to 5 hours.
In some embodiments of the present invention, the first alcohol solvent and the second alcohol solvent are each independently selected from at least one lower alcohol having 1 to 5 carbon atoms, preferably ethanol.
Drawings
Fig. 1 is a graph showing the electromagnetic shielding performance of the electromagnetic shielding material based on melamine sponge in the 8-12GHZ band according to embodiment 1 of the present invention.
Fig. 2 is a graph showing the electromagnetic shielding performance of the electromagnetic shielding material based on cotton gauze in the wavelength band of 8-12GHZ according to embodiment 2 of the present invention.
Fig. 3 is a graph showing the electromagnetic shielding performance of the electromagnetic shielding material based on cotton gauze in the wavelength band of 5-8GHZ according to embodiment 2 of the present invention.
Fig. 4 is a graph showing the electromagnetic shielding performance of the electromagnetic shielding material based on cotton gauze in the wavelength band of 12-18GHZ according to embodiment 2 of the present invention.
Detailed Description
The following detailed description of embodiments of the invention is intended to be illustrative, and is not to be construed as limiting the invention. Meanwhile, for the convenience of those skilled in the art to understand, some terms herein are explained and illustrated below, and it should be noted that the explanation and the illustration are only for helping those skilled in the art to understand the present invention, and should not be construed as a limitation to the technical solution of the present invention.
Herein, the "hydrophobic polymer alcohol solution" refers to a solution of a hydrophobic polymer dissolved in an alcohol solvent.
The "metal nanowire alcohol dispersion" refers to a dispersion formed by dispersing metal nanowires in an alcohol solvent.
The "metal nano network" refers to a latticed structure formed by metal nanowires, and these metal nanowires may be connected to each other, and when they are connected, they are not required to be completely consistent, and the latticed structure formed is not required to be completely uniform, so long as they are formed on the surface of the substrate more uniformly.
"electromagnetic shielding material" refers to any material that exhibits electromagnetic shielding properties. In the present document, a flexible material having a micro-skeleton structure is used as a substrate, and a metal nano-network is formed on the surface of the substrate, and the material exhibits excellent electromagnetic shielding performance. Herein, "microarchitectural" means that the flexible material as the substrate has some ductility and a loose structure, i.e., is not structurally dense, such that the metal nanonetwork may not be present only on the outer surface of the substrate, but may form a microarchitectural surface within the substrate. The material having such a micro-skeleton structure is not particularly limited, and may be, for example, a sponge, or some fiber fabrics, etc., including but not limited to cotton gauze, melamine sponge, etc. These microarchitectures may be present as a woven or lap-jointed armature of 10 to 100 microns in diameter. It may also have some loose cell structure at the same time.
The invention provides an electromagnetic shielding material, comprising: the substrate is a flexible material with a micro-skeleton structure; and a metal nano network formed on a surface of the substrate, the metal nano network including metal nanowires that are overlapped with each other.
The diameter of the micro-skeleton structure of the flexible material that can be used as the substrate may be 10 microns to 100 microns, for example, 10 microns to 90 microns, 10 microns to 80 microns, or 10 microns to 70 microns. The usable substrate can be melamine sponge, and the thickness of the melamine sponge can be 0.1-0.5 cm. The substrate can also be cotton gauze, and the thickness of the cotton gauze can be 0.4-1.5 mm.
In at least some embodiments of the present invention, the metal nano-network has a thickness of 1 to 5 micrometers on the surface of the substrate. Thereby, the electromagnetic shielding performance of the electromagnetic shielding material can be improved.
The preparation method comprises the steps of mixing an ethanol solution of a hydrophobic high-molecular polymer and an ethanol dispersion liquid of the metal nanowires to prepare slurry, and then soaking the substrate in the slurry to enable the surface of the micro-skeleton structure of the substrate to be covered with a layer of metal nano network. The metal nanowires and the hydrophobic high molecular polymer are respectively adopted to prepare ethanol solutions with specific proportions, the solutions are mixed, and the flexible substrate is directly dip-dyed, so that the flexible substrate has electromagnetic shielding performance. The method has the advantages of simple process, continuous production, mild process, quick molding, low cost, unlimited product size, adjustable optical and electromagnetic properties and the like. Compared with the traditional metal wire weaving technology, the method has remarkable advantages.
The scheme of the invention will be explained with reference to the examples. It will be appreciated by those skilled in the art that the following examples are illustrative of the invention only and should not be taken as limiting the scope of the invention. The examples, where specific techniques or conditions are not indicated, are to be construed according to the techniques or conditions described in the literature in the art or according to the product specifications. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products commercially available.
Example 1
Experimental group 1
The electromagnetic shielding material-silver nanowire sponge is prepared according to the following method:
firstly, dissolving powdered PVB in ethanol, heating to 80 ℃, and stirring for 1 hour to prepare a PVB ethanol solution with the mass percentage (PVB + ethanol) × 100%) of 1%.
Secondly, preparing a silver nanowire ethanol dispersion liquid with the concentration of 10mg/mL (the diameter of the silver nanowire is 50nm), then adding the silver nanowire ethanol dispersion liquid with the mass of the PVB ethanol solution 1/10 into the PVB ethanol solution, and stirring for 10min to obtain a mixed solution, namely the slurry.
And finally, soaking the melamine sponge with the thickness of 0.1cm in the slurry, taking out the melamine sponge after the melamine sponge is fully soaked, and naturally drying to obtain the silver nanowire sponge.
The electromagnetic shielding material-silver nanowire sponge is prepared according to the following method:
firstly, dissolving powdered PVB in ethanol, heating to 80 ℃, and stirring for 1 hour to prepare a PVB ethanol solution with the mass percentage of 1%.
Secondly, preparing silver nanowire ethanol dispersion liquid with the concentration of 10mg/mL (wherein the diameter of the silver nanowire is 50nm), then adding the silver nanowire ethanol dispersion liquid with the mass of the PVB ethanol solution 1/10 into the PVB ethanol solution, and stirring for 10min to obtain mixed solution, namely the slurry.
And finally, soaking the melamine sponge with the thickness of 0.2cm in the slurry, taking out the melamine sponge after the melamine sponge is fully soaked, and naturally drying to obtain the silver nanowire sponge.
Experimental group 3
The electromagnetic shielding material-silver nanowire sponge is prepared according to the following method:
firstly, dissolving powdered PVB in ethanol, heating to 80 ℃, and stirring for 1 hour to prepare a PVB ethanol solution with the mass percentage of 1%.
Secondly, preparing a silver nanowire ethanol dispersion liquid with the concentration of 10mg/mL (wherein the diameter of the silver nanowire is 50nm), then adding the silver nanowire ethanol dispersion liquid with the mass of the PVB ethanol solution 1/10 into the PVB ethanol solution, and stirring for 10min to obtain a mixed solution, namely the slurry.
And finally, soaking the melamine sponge with the thickness of 0.3cm in the slurry, taking out the melamine sponge after the melamine sponge is fully soaked, and naturally drying to obtain the silver nanowire sponge.
Experimental group 4
The electromagnetic shielding material-silver nanowire sponge is prepared according to the following method:
firstly, dissolving powdered PVB in ethanol, heating to 80 ℃, and stirring for 1 hour to prepare a PVB ethanol solution with the mass percentage (PVB + ethanol) × 100%) of 1%.
Secondly, preparing a silver nanowire ethanol dispersion liquid with the concentration of 10mg/mL (the diameter of the silver nanowire is 50nm), then adding the silver nanowire ethanol dispersion liquid with the mass of the PVB ethanol solution 1/10 into the PVB ethanol solution, and stirring for 10min to obtain a mixed solution, namely the slurry.
And finally, soaking the melamine sponge with the thickness of 0.4cm in the slurry, taking out the melamine sponge after the melamine sponge is fully soaked, and naturally drying to obtain the silver nanowire sponge.
The electromagnetic shielding material-silver nanowire sponge is prepared according to the following method:
firstly, dissolving powdered PVB in ethanol, heating to 80 ℃, and stirring for 1 hour to prepare a PVB ethanol solution with the mass percentage of 1%.
Secondly, preparing silver nanowire ethanol dispersion liquid with the concentration of 10mg/mL (wherein the diameter of the silver nanowire is 50nm), then adding the silver nanowire ethanol dispersion liquid with the mass of the PVB ethanol solution 1/10 into the PVB ethanol solution, and stirring for 10min to obtain mixed solution, namely the coating.
And finally, soaking the melamine sponge with the thickness of 0.5cm in the slurry, taking out the melamine sponge after the melamine sponge is fully soaked, and naturally drying to obtain the silver nanowire electromagnetic shielding melamine sponge.
The following performance characterizations were performed for the electromagnetic shielding materials of each experimental group, and the results are shown in fig. 1 and table 1 below:
electromagnetic shielding performance: and detecting the percentage of the electromagnetic wave intensity and incident wave intensity of the electromagnetic wave which does not penetrate through the electromagnetic shielding material in the 5GHz-18GHz wave band range by using a vector network analyzer, and converting the percentage into decibel for representation.
Table 1 results of characterization of the experimental groups
| Experimental group | 1 | 2 | 3 | 4 | 5 |
| Electromagnetic shielding performance (decibel) | 20 | 30 | 40 | 50 | 60 |
Fig. 1 shows only the electromagnetic shielding performance results of the electromagnetic shielding material based on melamine sponges with different thicknesses in the wavelength range of 8-12 GHZ. The electromagnetic shielding performance results given in table 1 are the maximum values corresponding to different experimental groups of electromagnetic shielding materials within the wavelength range of 5GHz-18 GHz.
As is apparent from fig. 1 and the results given from table 1, the electromagnetic shielding performance is higher as the intensity of the transmitted electromagnetic wave is lower as the thickness of the sponge is thicker.
Example 2
experimental group 1
The electromagnetic shielding material, namely the silver nanowire cotton gauze, is prepared by the following method:
firstly, dissolving powdered PVB in ethanol, heating to 80 ℃, and stirring for 1 hour to prepare a PVB ethanol solution with the mass percentage of 1%.
Secondly, preparing a silver nanowire ethanol dispersion liquid with the concentration of 10mg/mL (wherein the diameter of the silver nanowire is 50nm), then adding the silver nanowire ethanol dispersion liquid with the mass of the PVB ethanol solution 1/10 into the PVB ethanol solution, and stirring for 10min to obtain a mixed solution, namely the slurry.
And finally, soaking the cotton gauze with the thickness of 0.4mm in the slurry, taking out the cotton gauze after the cotton gauze is fully soaked, and naturally drying to obtain the silver nanowire cotton gauze.
The electromagnetic shielding material, namely the silver nanowire cotton gauze, is prepared by the following method:
firstly, dissolving powdered PVB in ethanol, heating to 80 ℃, and stirring for 1 hour to prepare a PVB ethanol solution with the mass percentage of 1%.
Secondly, preparing a silver nanowire ethanol dispersion liquid with the concentration of 10mg/mL (wherein the diameter of the silver nanowire is 50nm), then adding the silver nanowire ethanol dispersion liquid with the mass of the PVB ethanol solution 1/10 into the PVB ethanol solution, and stirring for 10min to obtain a mixed solution, namely the slurry.
And finally, soaking the cotton gauze with the thickness of 0.7mm in the slurry, taking out the cotton gauze after the cotton gauze is fully soaked, and naturally drying to obtain the silver nanowire cotton gauze.
Experimental group 3
The electromagnetic shielding material, namely the silver nanowire cotton gauze, is prepared by the following method:
firstly, dissolving powdered PVB in ethanol, heating to 80 ℃, and stirring for 1 hour to prepare a PVB ethanol solution with the mass percentage of 1%.
Secondly, preparing a silver nanowire ethanol dispersion liquid with the concentration of 10mg/mL (wherein the diameter of the silver nanowire is 50nm), then adding the silver nanowire ethanol dispersion liquid with the mass of the PVB ethanol solution 1/10 into the PVB ethanol solution, and stirring for 10min to obtain a mixed solution, namely the slurry.
And finally, soaking the cotton gauze with the thickness of 1.0mm in the slurry, taking out the cotton gauze after the cotton gauze is fully soaked, and naturally drying to obtain the silver nanowire cotton gauze.
Experimental group 4
The electromagnetic shielding material, namely the silver nanowire cotton gauze, is prepared by the following method:
firstly, dissolving powdered PVB in ethanol, heating to 80 ℃, and stirring for 1 hour to prepare a PVB ethanol solution with the mass percentage of 1%.
Secondly, preparing a silver nanowire ethanol dispersion liquid with the concentration of 10mg/mL (wherein the diameter of the silver nanowire is 50nm), then adding the silver nanowire ethanol dispersion liquid with the mass of the PVB ethanol solution 1/10 into the PVB ethanol solution, and stirring for 10min to obtain a mixed solution, namely the slurry.
And finally, soaking the cotton gauze with the thickness of 1.4mm in the slurry, taking out the cotton gauze after the cotton gauze is fully soaked, and naturally drying to obtain the silver nanowire cotton gauze.
The prepared electromagnetic shielding material was characterized by the same method as example 1, and the results are shown in fig. 2 and table 2 below:
table 2 results of characterization of each experimental group
Fig. 2 shows the results of the electromagnetic shielding performance of the electromagnetic shielding material based on cotton gauze with different thickness in the wavelength range of 8-12 GHZ. Fig. 3 shows the results of the electromagnetic shielding performance of the electromagnetic shielding material based on cotton gauze with different thickness in the wavelength range of 5-8 GHZ. Fig. 4 shows the results of the electromagnetic shielding performance of the electromagnetic shielding material based on cotton gauze with different thickness in the wavelength range of 12-18 GHZ. The electromagnetic shielding performance results given in table 1 are the maximum values corresponding to different experimental groups of electromagnetic shielding materials within the wavelength range of 5GHz-18 GHz.
As can be seen from the results shown in fig. 2 to 4 and table 2, the electromagnetic shielding performance is higher as the intensity of the transmitted electromagnetic wave is lower as the thickness of the cotton gauze is thicker.
Example 3
Embodiment 3 provides an electromagnetic shielding material, namely silver nanowire cotton gauze, which is prepared by the method of the experimental group 3 in the embodiment 2, and is characterized in that: the hydrophobic high molecular polymer is polyurethane.
The electromagnetic shielding performance result of the electromagnetic shielding material is 42 decibels.
Example 4
Embodiment 4 provides an electromagnetic shielding material, namely silver nanowire cotton gauze, which is prepared by the method of the experimental group 3 in the embodiment 2, and is characterized in that: the concentration of the PVB ethanol solution is 2%.
The electromagnetic shielding material obtained by the experiment showed 40 db electromagnetic shielding performance, which also showed excellent electromagnetic shielding performance, but the flexibility of the electromagnetic shielding material prepared in this example was reduced compared to that of experiment group 3 in example 2.
Example 5
The electromagnetic shielding performance result of the electromagnetic shielding material is 45 decibels.
Example 6
The electromagnetic shielding performance result of the electromagnetic shielding material is 35 decibels.
Comparative example 1
Comparative example 1 provides an electromagnetic shielding material, silver nanowire cotton gauze, prepared according to the method of experimental group 3 in example 2, except that: the polymer used is PVP.
The electromagnetic shielding performance result of the electromagnetic shielding material is 40 decibels measured by experiments, but the PVP is dissolved in water, so when the electromagnetic shielding material is applied, a metal network structure formed by the material is easily damaged after the material is in water, the electromagnetic shielding performance of the electromagnetic shielding material is reduced, even the material fails, and the electromagnetic shielding performance is not shown any more.
The terms "first", "second" and "first" are used herein for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.
Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art within the scope of the present invention.
Claims (16)
1. An electromagnetic shielding material, comprising:
the substrate is a flexible material with a micro-skeleton structure; and
a metal nano-network formed on a surface of the substrate, the metal nano-network including metal nanowires that are overlapped with each other;
the metal nano network is formed on the surface of the substrate through hydrophobic high molecular polymer;
the hydrophobic high molecular polymer comprises at least one selected from polyvinyl butyral, polymethyl methacrylate, polyvinylidene fluoride and polyurethane;
soaking the substrate in a slurry to form the metal nano-network on the surface of the substrate, wherein the slurry contains a hydrophobic high molecular polymer alcohol solution and a metal nanowire alcohol dispersion liquid;
the hydrophobic high-molecular polymer alcoholic solution is an alcoholic solution containing a hydrophobic high-molecular polymer, and the metal nanowire alcoholic dispersion liquid is an alcoholic solution containing the metal nanowires;
the substrate is a porous sponge.
2. The electromagnetic shielding material of claim 1, wherein the diameter of the micro-skeletal structure of the substrate is in the range of 10 microns to 100 microns.
3. The electromagnetic shielding material of claim 1, wherein the thickness of the metal nano-network on the surface of the substrate is 1-5 μm.
4. The electromagnetic shielding material of claim 1, wherein the metal nanowires are one-dimensional metal nanowires.
5. The electromagnetic shielding material of claim 1, wherein the metal nanowires are at least one selected from the group consisting of gold, silver, copper, and nickel.
6. The electromagnetic shielding material of claim 1, wherein the metal nanowires have a diameter of 50-200 nm.
7. The electromagnetic shielding material of claim 1, wherein the hydrophobic polymer alcohol solution is an alcohol solution containing a hydrophobic polymer, and the metal nanowire alcohol dispersion is an alcohol solution containing the metal nanowires.
8. The electromagnetic shielding material of claim 1, wherein the mass ratio of the hydrophobic high molecular polymer alcohol solution to the metal nanowire alcohol dispersion is 5: 1-20: 1.
9. The electromagnetic shielding material of claim 1, wherein the mass ratio of the hydrophobic high molecular polymer alcohol solution to the metal nanowire alcohol dispersion is 5: 1-15: 1.
10. The electromagnetic shielding material of claim 1, wherein the hydrophobic polymer is 0.5-2% by weight of the hydrophobic polymer in the hydrophobic polymer alcoholic solution.
11. The electromagnetic shielding material of claim 1, wherein the concentration of the metal nanowires in the alcohol dispersion of metal nanowires is 5 to 20 mg/ml.
12. A method of preparing the electromagnetic shielding material according to any one of claims 1 to 11, comprising:
dissolving a hydrophobic high molecular polymer in a first alcohol solvent so as to obtain a hydrophobic high molecular polymer alcohol solution;
dispersing the metal nanowires in a second alcohol solvent to obtain a metal nanowire alcohol dispersion;
mixing the hydrophobic high molecular polymer alcohol solution and the metal nanowire alcohol dispersion liquid, and stirring to obtain slurry;
and soaking a substrate in the slurry, and drying to obtain the electromagnetic shielding material.
13. The method according to claim 12, wherein the hydrophobic polymer is dissolved in the first alcohol solution at 30-90 ℃.
14. The method of claim 12, wherein the hydrophobic polymer is dissolved in the first alcohol solution at 80 degrees celsius.
15. The method according to claim 12, wherein the first alcohol solvent and the second alcohol solvent are each independently selected from at least one lower alcohol having 1 to 5 carbon atoms.
16. The method of claim 12, wherein the first alcohol solvent and the second alcohol solvent are each independently ethanol.
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| CN111535044B (en) * | 2020-06-01 | 2022-10-18 | 中国科学院合肥物质科学研究院 | Electromagnetic shielding and hydrophobic functional fabric with high absorption characteristic and preparation method thereof |
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