Two-dimensional structural material film, method for manufacturing the same, and electronic device.

Abstract

[Problem] To provide a two-dimensional structural material film that can improve the functionality derived from the two-dimensional structural material, a method for manufacturing the same, and an electronic device using the two-dimensional structural material film. [Solution] The two-dimensional structural material film 11 is composed of two-dimensional structural material particles 1. The c-axis orientation of the two-dimensional structural material particles 1 is in the range of 70 to 100%, and the porosity is in the range of 13 to 67%. [Selected Figure] Figure 3

Description

[Technical Field]

[0001] The present invention relates to a two-dimensional structural material film, a method for manufacturing the same, and an electronic device using the two-dimensional structural material film. [Background technology]

[0002] The present inventors have proposed a two-dimensional structural material film composed of an aerosol deposition film of a two-dimensional structural material such as graphene and functional material particles such as magnetic metal particles, wherein the two-dimensional structural material particles are stacked to exhibit c-axis orientation, and the functional material particles are encapsulated by the two-dimensional structural material particles (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-179429 [Patent Document 2] Japanese Patent Publication No. 2022-179441 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] However, conventional aerosol deposition methods result in significant raw material loss and make it difficult to control the functionality of the deposited film, such as its electromagnetic wave absorption characteristics.

[0005] Therefore, the present invention relates to a two-dimensional structural material. Electromagnetic wave absorption characteristics The objective is to provide a two-dimensional structural material film and a method for manufacturing the same that can improve performance. [Means for solving the problem]

[0006] The two-dimensional structural material film of the present invention is It is composed of two-dimensional structural material particles and a water-soluble binder. The c-axis orientation degree of the two-dimensional structure material particles is included in the range of 70 to 100%, The mass ratio of the two-dimensional structure material particles to the total mass of the two-dimensional structure material particles and the water-soluble binder but is included in the range of 80 to 98 wt%, and the porosity is included in the range of 13 to 67% Occasionally, The aforementioned two-dimensional structural material particles have an integrated intensity ratio of I between the D-band and G-band of the Raman spectroscopic spectrum. D / I G Graphene with a coefficient of less than 1.0, It has electromagnetic wave absorption and shielding properties.

[0007] In addition, the two-dimensional structure material film of the present invention is composed of two-dimensional structure material particles and a water-soluble binder, the c-axis orientation degree of the two-dimensional structure material particles is included in the range of 70 to 100%, the mass ratio of the two-dimensional structure material particles to the total mass of the two-dimensional structure material particles and the water-soluble binder but is included in the range of 80 to 98 wt%, the surface resistance is 1×10 3 Ω or less the law of nature, The aforementioned two-dimensional structural material particles have an integrated intensity ratio of I between the D-band and G-band of the Raman spectroscopic spectrum. D / I G Graphene with a coefficient of less than 1.0, It has electromagnetic wave absorption and shielding properties.

[0008] The manufacturing method of the two-dimensional structure material film of the present invention includes a step of adjusting a raw material liquid agent such that the mass ratio of the two-dimensional structure material particles to water is included in the range of 5 to 20 wt% and the mass ratio of the two-dimensional structure material particles to the total mass of the two-dimensional structure material particles and the water-soluble binder is included in the range of 80 to 98 wt%; a step of applying the raw material liquid agent onto a substrate according to a jet dispensing method or a two-fluid spray method, and heating the raw material liquid agent to remove the water from the raw material liquid agent to form an intermediate film; The process includes applying a load of 0.5 to 5.0 t in the thickness direction to the interlayer film for 1 sec to 60 min.

[0009] In the two-dimensional structural material film with this configuration, the c-axis orientation of the two-dimensional structural material particles falls within the range of 70-100%. Due to the unique two-dimensionality of its chemical bonding state, the two-dimensional structural material has extremely high electrical conductivity in the c-plane (ab-plane) compared to the c-axis direction, making it usable as an electromagnetic wave shielding and absorption material. Resin composite sheets of magnetic flattened powders such as Sendust have been widely commercialized as noise suppression sheets that utilize magnetic loss, used as near-field electromagnetic wave absorption sheets in mobile devices such as mobile communications devices. However, the recent increase in electromagnetic wave utilization bandwidths such as 5G and 6G, and the demand for thin sheets, have led to a decrease in magnetic permeability and a reduction in magnetic material volume, resulting in a deterioration of electromagnetic wave absorption characteristics. In this respect, the two-dimensional structural material film that utilizes conductivity loss is far more advantageous than conventional magnetic noise suppression sheets because its electromagnetic wave absorption characteristics increase with increasing frequency and it is not affected by the deterioration of characteristics due to volume reduction.

[0010] Two-dimensional structural materials also possess extremely high thermal conductivity at the c-plane, making them suitable for use as heat dissipation or thermal dispersion sheets. The simultaneous electromagnetic wave absorption / shielding and thermal dispersion / dissipation properties of two-dimensional structural material films are advantageous for applications in mobile communication equipment and other devices where heat generation due to increasing data processing loads is a problem. Similar to carbon nanotubes, two-dimensional structural material films exhibit significant changes in electrical resistance with mechanical deformation, making them suitable for use as pressure or strain sensors. Carbon-based materials are advantageous for the above applications because they are lower in density and lighter than inorganic materials such as metals and ceramics.

[0011] Since the porosity of the two-dimensional structural material film falls within the range of 13-67%, the volume occupancy rate of the two-dimensional structural material is improved. This, in turn, improves the functionality of the two-dimensional structural material, such as its electromagnetic wave absorption properties. [Brief explanation of the drawing]

[0012] [Figure 1] A schematic diagram showing a cross-section of an electronic device as one embodiment of the present invention. [Figure 2] A schematic diagram showing a cross-section of an electronic device as one embodiment of the present invention. [Figure 3] SEM image of a cross-section of a two-dimensional structural material film as one embodiment of the present invention. [Figure 4] SEM image of a cross-section of the interlayer. [Figure 5] An explanatory diagram showing the integrated intensity ratio (ID / IG) and transmission attenuation rate for each frequency. [Figure 6] An explanatory diagram regarding the load and c-axis orientation during the manufacturing of two-dimensional structural material films. [Figure 7] Diagram illustrating the porosity and transmission attenuation rate (3.7 GHz) of the sample. [Figure 8] An explanatory diagram showing the surface resistance and transmission attenuation rate (3.7 GHz) of the sample. [Figure 9] An explanatory diagram showing the surface resistance and transmission attenuation rate (3.7 GHz) of the sample. [Figure 10] Diagram illustrating the porosity and transmission attenuation rate (20 GHz) of the sample. [Figure 11] An explanatory diagram regarding the surface resistance and transmission attenuation rate (20 GHz) of the sample. [Figure 12] An explanatory diagram regarding the surface resistance and transmission attenuation rate (20 GHz) of the sample. [Figure 13] Diagram illustrating the porosity and transmission attenuation rate (30 GHz) of the sample. [Figure 14] An explanatory diagram regarding the surface resistance and transmission attenuation rate (30 GHz) of the sample. [Figure 15] An explanatory diagram regarding the surface resistance and transmission attenuation rate (30 GHz) of the sample. [Figure 16] Diagram illustrating the porosity and transmission attenuation rate (40 GHz) of the sample. [Figure 17] An explanatory diagram regarding the surface resistance and transmission attenuation rate (40 GHz) of the sample. [Figure 18]An explanatory diagram regarding the surface resistance and transmission attenuation rate (40 GHz) of the sample. [Figure 19] This figure shows the electromagnetic shielding characteristics of a sample in the near field, measured using the microstrip line method. [Figure 20] This figure shows the far-field electromagnetic shielding characteristics of a sample measured using the free-space method. [Modes for carrying out the invention]

[0013] (Configuration of electronic equipment) Figure 1 is a schematic diagram showing a cross-sectional view of the configuration of an electronic device 10 according to one embodiment of the present invention. As shown in Figure 1, the electronic device 10 of the present invention comprises a two-dimensional structural material film 11 and an electronic device body 12. The electronic device body 12 is, for example, an electrical circuit element, circuit board, wires, functional components, etc., used in electrical products such as office automation equipment such as televisions, speakers or microphones, smartphones, and computers.

[0014] If the electronic device body 12 is a communication device or the like that utilizes a high-frequency band, the two-dimensional structural material film 11 can be used as a conductive noise suppression sheet or a heat dissipation or heat dispersion sheet. In this case, as shown in Figure 1, it is preferable that the electronic device body 12, which is the source of electromagnetic waves or heat, and the two-dimensional structural material film 11 be in close contact in the electronic device 10. Furthermore, if insulation between the electronic device body 12, which is the source of electromagnetic waves or heat, and the two-dimensional structural material film is necessary as needed, an insulating material 13, which is made of an insulating substrate or insulating film, may be interposed between the electronic device body 12 and the two-dimensional structural material film. Alternatively, the two-dimensional structural material film 11 may be placed in close proximity to the electronic device body 12 via an insulating film. In this case, as shown in Figure 2, in the electronic device 10, the two-dimensional structural material film 11 and the electronic device body 12 may be separated by an insulating material 13, preferably with a distance of 5 μm or less.

[0015] The two-dimensional structural material film 11 may be arranged to cover a portion of the surface of the electronic device body 12. Alternatively, if the electronic device body 12 consists of components and circuits such as an IC, the two-dimensional structural material film 11 may be arranged to cover the entire surface of the electronic device body 12.

[0016] The insulating material 13 is not particularly limited, but may be at least one compound selected from the group consisting of various synthetic resins such as polyimide, polyethylene terephthalate (PET), acrylic, polyacetal, polycarbonate, polyethylene, polypropylene, and silicone rubber, and various ceramics such as quartz, alumina, zirconia, silicon carbide, and silicon nitride.

[0017] In the electronic device 10 shown in Figure 2, the two-dimensional structural material film can be used as a noise shielding sheet. In this case, the two-dimensional structural material film 11 may be placed relative to the electronic device body 12 with an insulating material 13 or air in between, preferably at a distance of more than 5 μm (i.e., far field).

[0018] (Composition of two-dimensional structural material films) Figure 3 shows an SEM image of a cross-section of a two-dimensional structural material film 11 as an embodiment of the present invention. The two-dimensional structural material film 11 is composed of a plurality of two-dimensional structural material particles 1 and a water-soluble binder, which are shown in black in Figure 3. In addition to the voids 2 shown in white in Figure 3, the two-dimensional structural material film 11 contains impurities shown in gray in Figure 1.

[0019] The degree of c-axis orientation of the two-dimensional structural material particles 1 in the two-dimensional structural material film 11 is preferably in the range of 70 to 100%. The porosity of the two-dimensional structural material film 11 is preferably in the range of 13 to 67%, more preferably in the range of 13 to 50%, and even more preferably in the range of 13 to 31%. The surface resistance of the two-dimensional structural material film 11 is preferably 1000 Ω or less, more preferably in the range of 0.5 to 200 Ω. Furthermore, when the film thickness of the two-dimensional structural material film 11 is 20 μm or less, the surface resistance of the two-dimensional structural material film is preferably in the range of 5 to 100 Ω. For example, in an SEM image of a cross-section of the two-dimensional structural material film 11, the area ratio of the image region of the void 2 (see white area in Figure 3) may be measured as the porosity of the two-dimensional structural material film. The thickness of the two-dimensional structural material film 11 is, for example, in the range of 1 to 200 μm, preferably in the range of 1 to 100 μm, and even more preferably in the range of 1 to 50 μm. The thickness of the two-dimensional structural material film 11 is selected to any thickness depending on the characteristics of the electronic device used (such as whether it is used in the near field or the far field).

[0020] (Manufacturing method) An embodiment of a method for manufacturing the two-dimensional structural material film 11 having the above configuration will now be described. First, a raw material liquid containing two-dimensional structural material particles 1, a water-soluble binder, and water is prepared. For example, the raw material liquid is prepared such that the mass ratio of two-dimensional structural material particles 1 to water is preferably in the range of 5 to 20 wt%, more preferably in the range of 5 to 15 wt%, and even more preferably in the range of 5 to 10 wt%, and the mass ratio of two-dimensional structural material particles 1 to the total mass of two-dimensional structural material particles 1 and water-soluble binder is preferably in the range of 80 to 98 wt%, more preferably in the range of 90 to 98 wt%, and even more preferably in the range of 95 to 98 wt%. The mass ratio of two-dimensional structural material particles 1 to water may be changed to 3 to 25 wt% or 7 to 15 wt%, etc. The mass ratio of two-dimensional structural material particles 1 to the total mass of two-dimensional structural material particles 1 and water-soluble binder may be changed to 75 to 95 wt% or 85 to 99 wt%, etc.

[0021] The two-dimensional structure material particles 1 include not only single-layer two-dimensional structure materials but also multi-layer two-dimensional structure material particles laminated so that their basal planes overlap. Materials having a single-layer or multi-layer two-dimensional structure, such as graphene, hexagonal boron nitride (h-BN), TMDs such as MoS2, phosphorene (black phosphorus), and MXene (maxine), which is a conductive carbide or nitride, may be adopted as the two-dimensional structure material. The average diameter of the two-dimensional structure material particles 1 is in the range of 0.1 to 100 μm, preferably in the range of 0.5 to 50 μm, more preferably in the range of 0.5 to 10 μm, and even more preferably in the range of 0.5 to 5 μm. The thickness is in the range of 0.3 to 300 nm (1 to 1000 layers of two-dimensional structure material molecules), preferably in the range of 0.3 to 30 nm (1 to 100 layers of two-dimensional structure material molecules), and more preferably in the range of 0.3 to 10 nm (1 to 30 layers of two-dimensional structure material molecules).

[0022] Since reduced graphene oxide rGO (chemically exfoliated) has a large amount of defects and high resistance, the integrated intensity ratio I of the D band and G band of the Raman spectrum, which is a parameter of the amount of graphene defects D / I G of graphene is preferably less than 1, more preferably less than 0.5. In particular, when the integrated intensity ratio exceeds 2, there is a problem that the value of the surface resistance increases. Since there may be an overlap of the absorption specific to graphene (interband transition) different from graphite, the number of graphene layers is preferably 30 layers or less, more preferably 10 layers or less, and even more preferably 5 layers or less. Functional group-modified graphene such as amino group and carboxyl group may be adopted in addition to unmodified graphene. Furthermore, as the two-dimensional structure material particles 1, a plurality of materials may be adopted. For example, graphene particles with 10 or less layers and graphene particles with 10 or more layers may be used as the two-dimensional structure material particles 1.

[0023] In FIG. 5, the relationship between the integrated intensity ratio I D / I G and the transmission attenuation rate is shown for each frequency. The transmission attenuation rate is measured by the microstrip method described later. As shown in FIG. 5, the integrated intensity ratio I D / I G It has been shown that when the integral intensity ratio exceeds 1, the transmission attenuation rate decreases in all frequency bands. As this indicates, the two-dimensional structural material particles used as raw materials have an integral intensity ratio of 1. D / I G It is preferable that the graphene has a coefficient of less than 1.0.

[0024] Examples of water-soluble binders include cellulose nanofiber (CNF), carboxymethylcellulose (CMC), sodium carboxymethylcellulose (CMC-Na), methylcellulose (MC), hydroxypropyl methylcellulose (HPMC), hydroxyethyl methylcellulose (HEMC), polyvinylpyrrolidone (PVP) resins, polyvinyl alcohol (PVA) resins, water-soluble epoxy resins, and water-soluble urethane resins.

[0025] As the water-soluble binder, it is preferable to use cellulosic compounds such as CNF, PVP resins, PVA resins, and / or water-soluble epoxy resins, all of which have a heat resistance temperature of 200°C or higher. Cellulosic compounds are thixotropic, which suppresses the precipitation of two-dimensional structural material particles (fillers), making them more suitable for film formation by jet dispensing (JD) or spraying than PVP and PVA. CNF modified with polar groups, such as sulfated esterified CNF (S-CNF), is preferred because the electrostatic force between fibers prevents aggregation, resulting in a solution with good filler dispersibility.

[0026] Next, the raw material liquid is applied to the substrate according to the jet dispensing method (JD method). Either a contact method or a non-contact method may be used for the jet dispensing; for example, a non-contact method is employed.

[0027] The raw material liquid may be applied to the substrate by a spray method in addition to the JD method. Any spray method can be used, including conventional spray methods, such as two-fluid spraying, electrostatic spraying, and cold spraying. Furthermore, the raw material liquid may be applied to the substrate by an aerosol deposition method (AD method) capable of reproducing the embodiment of the present invention. The raw material liquid may also be applied to the substrate using a combination of multiple methods.

[0028] After droplets of the discharged raw material liquid are scanned planarly across the substrate to form a film, the film is heated (for example, at a temperature of 40-70°C) to remove water from the raw material liquid, thereby forming an interlayer. Heating temperatures exceeding 80°C are undesirable because they result in a rougher film quality. Figure 3 shows an SEM image of a cross-section of the two-dimensional structural material film, and Figure 4 shows an SEM image of the interlayer before load application. As shown in Figures 3 and 4, the interlayer before load application has a higher void area and, consequently, a higher porosity compared to the two-dimensional structural material film.

[0029] As the substrate, a substrate made of at least one compound selected from the group consisting of flexible sheets such as polyimide, polyethylene terephthalate (PET), acrylic, polyacetal, polycarbonate, polyethylene, polypropylene, silicone rubber, and pyrolytic graphite, and various ceramics such as quartz, alumina, zirconia, silicon carbide, and silicon nitride is used. The thickness of the substrate is not particularly limited, but for example it is 200 μm or less, and any appropriate thickness can be selected depending on the application.

[0030] Then, a predetermined load is applied to the interlayer in the thickness direction, thereby creating a two-dimensional structural material film 11.

[0031] If the substrate surface characteristics make it prone to delamination, a pre-layer such as a water-soluble binder can be formed before film formation to prevent delamination. Alternatively, the film can be used as a film sheet in a state where it has been intentionally delaminated from the substrate.

[0032] The electronic device 10 is manufactured by placing the obtained two-dimensional structural material film 11 on the surface of the electronic device body 12. For example, the electronic device 10 can be manufactured by thermocompression bonding the two-dimensional structural material film 11 to the electronic device body 12 such that the substrate portion of the two-dimensional structural material film 11 is in contact with the surface of the electronic device body 12.

[0033] The method for placing the two-dimensional structural material film 11 on the electronic device body 12 is not limited to thermocompression bonding; direct coating methods such as dispensing and spraying can also be used.

[0034] (sample)

[0035] (Sample 1) As a two-dimensional structural material particle 1, the particle size d 50 Unmodified graphene particles (manufactured by Graphene Platform, Inc.) were used, with a thickness of 2.4 μm, a particle number ratio of 70% or more with 10 or fewer layers (thickness in the c-axis direction of approximately 3.3 nm or less), and a particle number ratio of less than 30% with more than 10 layers (thickness in the c-axis direction of approximately 3.3 nm). Sulfate-esterified CNF (S-CNF, manufactured by Yokogawa Biofrontier Corporation) was used as the water-soluble binder. A raw material liquid was prepared in which the mass ratio of 2D structural material particles 1 to water was 20 wt%, and the mass ratio of 2D structural material particles 1 to the total mass of 2D structural material particles 1 and the water-soluble binder was 93.75 wt%.

[0036] A flexible sheet substrate (manufactured by DuPont) measuring 35 × 35 mm × 125 μm thick, made of Kapton polyimide ("Kapton" is a registered trademark), was coated with a raw material liquid according to the non-contact JD method. By heating the substrate, water was removed from the raw material liquid, resulting in the creation of an interlayer film with a thickness of 130 μm, which served as Sample 1.

[0037] (Sample 2) A two-dimensional structural material film 11 with a thickness of 78 μm was fabricated as sample 2 by applying a load of 0.5 t in the thickness direction to the interlayer film, which was sample 1, for 3 seconds.

[0038] (Sample 3) A two-dimensional structural material film 11 with a thickness of 53 μm was fabricated as sample 3 by applying a load of 5 tons in the thickness direction to the interlayer film, which was sample 1, for 3 seconds.

[0039] (Sample 4) A raw material solution was prepared in which the mass ratio of 2D structural material particles 1 to water was 13.3 wt%, and the mass ratio of 2D structural material particles 1 to the total mass of 2D structural material particles 1 and water-soluble binder was 98.0 wt%. Except for this, an interfilm with a thickness of 126 μm was prepared as sample 4 according to the same preparation conditions as sample 1.

[0040] (Sample 5) A two-dimensional structural material film 11 with a thickness of 72 μm was fabricated as sample 5 by applying a load of 0.5 t in the thickness direction to the interlayer film, which was sample 4, for 3 seconds.

[0041] (Sample 6) A two-dimensional structural material film 11 with a thickness of 49 μm was fabricated as sample 6 by applying a load of 5 tons in the thickness direction to the interlayer film, sample 4, for 3 seconds.

[0042] (Sample 7) After preparing the same raw material solution as for Sample 1, the raw material solution was applied to the same substrate as for Sample 1 according to the two-fluid spray method, and the substrate was heated to remove water from the raw material solution, thereby creating an interlayer film with a thickness of 17 μm, which was Sample 7.

[0043] (Sample 8) A two-dimensional structural material film 11 with a thickness of 10 μm was fabricated as sample 8 by applying a load of 0.5 t in the thickness direction to the interlayer film, which was sample 7, for 3 seconds.

[0044] (Sample 9) A 2D structural material film 11 with a thickness of 7 μm was fabricated as sample 8 by applying a load of 5t in the thickness direction to the interlayer film, sample 7, for 3 seconds.

[0045] (Sample 10) A raw material solution was prepared using the two-dimensional structural material particles 1 and water-soluble binder from Sample 1, with a mass ratio of 2D structural material particles 1 to water of 5.6 wt% and a mass ratio of 2D structural material particles 1 to the total mass of 2D structural material particles 1 and water-soluble binder of 94.0 wt%. The raw material solution was applied to the same substrate as Sample 1 according to the non-contact JD method, and the substrate was heated to remove water from the raw material solution, thereby creating an interlayer with a thickness of 69 μm. A load of 1 ton was applied to this interlayer in the thickness direction for 3 seconds to create a two-dimensional structural material film 11 with a thickness of 23 μm, which was Sample 10.

[0046] (Other samples) After preparing the same raw material liquid as in Sample 1, the raw material liquid was applied to the same substrate as in Sample 1 using a non-contact JD method or a two-fluid spray method, and the substrate was heated to remove water from the raw material liquid, thereby creating an interlayer with a predetermined thickness as another sample. Furthermore, by applying a predetermined load to this interlayer for 3 seconds, a two-dimensional structural material film 11 with a predetermined thickness was created as another sample.

[0047] (Reference Sample 1) A mixed raw material consisting of graphene particles, which were used as two-dimensional structural material particle 1 in the preparation of samples 1 to 3, and phosphate-coated carbonyl iron particles (CIP) was sprayed onto a substrate according to the aerosol deposition method (AD method), thereby producing an AD film with a thickness of 6.2 μm as reference sample 1.

[0048] (porosity) The porosity of the two-dimensional structural material film 11 was measured from SEM images of the cross-sections of samples 1 to 9.

[0049] (plane resistance) The surface resistance of samples 1-9 and other samples was measured using the four-probe method.

[0050] (degree of orientation) Figure 6 shows the measurement results of the c-axis orientation for sample 1, sample 2, and sample 3, indicated by the circled sample number. The c-axis orientation F is defined by equation (1), where (FWHM)ψ / 2 is half of the full width at half maximum (FWHM) at the tilt axis ψ of the graphene (002) diffraction spot in the XRD broad-area reciprocal map.

[0051] Degree of c-axis orientation F(%)=100x(90-((FWHM)ψ / 2)) / 90‥(1).

[0052] Figure 6 shows the measurement results of the c-axis orientation of Reference Sample 1, indicated by black circles. The c-axis orientation of the two-dimensional structural material particles 1 of Sample 1, Sample 2, Sample 3, and Reference Sample 1 are 74.7%, 80.2%, 78.3%, and 62.8%, respectively. The c-axis orientation of the two-dimensional structural material particles 1 of Sample 1, which is a JD film, is higher than that of the two-dimensional structural material particles 1 of Reference Sample 1, which is an AD film. The c-axis orientation of the two-dimensional structural material particles 1 of Sample 2 and Sample 3, which were prepared by applying a load of 0.5 to 5 t to Sample 1, is higher than that of the two-dimensional structural material particles 1 of Sample 1. The c-axis orientation of the two-dimensional structural material particles 1 of Sample 2, which was prepared by applying a load of 0.5 t to Sample 1, is higher than that of the two-dimensional structural material particles 1 of Sample 3, which was prepared by applying a load of 5 t to Sample 1.

[0053] (Transmission attenuation rate) The transmission attenuation rate was measured using the microsplit line method. Specifically, a two-dimensional structural material film 11, used as the measurement sample, was fixed to the surface of a 20 mm square microstrip line with a conductor line width of 122 μm, characteristic impedance Z0 = 50 Ω, and size 5 μm apart using an 88 g glass weight, and the reflection coefficient S was obtained by applying a high-frequency signal. 11 and transmission coefficient S 21 From the value of transmission attenuation R tp They sought it.

[0054] Figure 7 shows the transmission attenuation rate R at a frequency of 3.7 GHz in the direction parallel to the main surface of each of the samples 1 to 9. tp The relationship between the measurement results and the porosity measurement results is shown by the corresponding number in black circle with a white number for each sample, and the transmission attenuation rate R at a frequency of 3.7 GHz in the direction perpendicular to the main surface of each of the samples 1 to 9 is shown. tp The relationship between the measurement results and the porosity measurement results is indicated by the corresponding circled number for each sample.

[0055] Figure 8 shows the transmission attenuation rate R at a frequency of 3.7 GHz in the direction parallel to the main surface of each of the samples 1-6 and other samples prepared by the non-contact JD method. tp The relationship between the measurement results and the surface resistance measurement results is shown along with the applied load applied to the two-dimensional structural material film 11. Figure 9 shows the transmission attenuation rate R at a frequency of 3.7 GHz in the direction parallel to the main surface of each of the samples 7-9 and other samples prepared by the two-fluid spray method. tp The relationship between the measurement results and the surface resistance measurement results is shown along with the applied load applied to the two-dimensional structural material film 11.

[0056] Figure 10 shows the transmission attenuation rate R at a frequency of 20 GHz in the direction parallel to the main surface of each of the samples 1 to 9. tp The relationship between the measurement results and the porosity measurement results is shown by the corresponding number in black circle with a white number for each sample, and the transmission attenuation rate R at a frequency of 20 GHz in the direction perpendicular to the main surface of each of the samples 1 to 9. tpThe relationship between the measurement results and the porosity measurement results is indicated by the corresponding circled number for each sample.

[0057] Figure 11 shows the transmission attenuation rate R at a frequency of 20 GHz in the direction parallel to the main surface of each of the samples 1-6 and other samples prepared by the non-contact JD method. tp The relationship between the measurement results and the surface resistance measurement results is shown along with the applied load applied to the two-dimensional structural material film 11. Figure 12 shows the transmission attenuation rate R at a frequency of 20 GHz in the direction parallel to the main surface of each of the samples 7-9 and other samples prepared by the two-fluid spray method. tp The relationship between the measurement results and the surface resistance measurement results is shown along with the applied load applied to the two-dimensional structural material film 11.

[0058] Figure 13 shows the transmission attenuation rate R at a frequency of 30 GHz in the direction parallel to the main surface of each of the samples 1 to 9. tp The relationship between the measurement results and the porosity measurement results is shown by the corresponding number in white with a black circle for each sample, and the transmission attenuation rate R at a frequency of 30 GHz in the direction perpendicular to the main surface of each of the samples 1 to 9. tp The relationship between the measurement results and the porosity measurement results is indicated by the corresponding circled number for each sample.

[0059] Figure 14 shows the transmission attenuation rate R at a frequency of 30 GHz in the direction parallel to the main surface of each of the samples 1-6 and other samples prepared by the non-contact JD method. tp The relationship between the measurement results and the surface resistance measurement results is shown along with the applied load applied to the two-dimensional structural material film 11. Figure 15 shows the transmission attenuation rate R at a frequency of 30 GHz in the direction parallel to the main surface of each of the samples 7-9 and other samples prepared by the two-fluid spray method. tp The relationship between the measurement results and the surface resistance measurement results is shown along with the applied load applied to the two-dimensional structural material film 11.

[0060] Figure 16 shows the transmission attenuation rate R at a frequency of 40 GHz in the direction parallel to the main surface of each of the samples 1 to 9. tpThe relationship between the measurement results and the porosity measurement results is shown by the corresponding number in black circle with a white number for each sample, and the transmission attenuation rate R at a frequency of 40 GHz in the direction perpendicular to the main surface of each of the samples 1 to 9. tp The relationship between the measurement results and the porosity measurement results is indicated by the corresponding circled number for each sample.

[0061] Figure 17 shows the transmission attenuation rate R at a frequency of 40 GHz in the direction parallel to the main surface of each of the samples 1-6 and other samples prepared by the non-contact JD method. tp The relationship between the measurement results and the surface resistance measurement results is shown along with the applied load applied to the two-dimensional structural material film 11. Figure 18 shows the transmission attenuation rate R at a frequency of 40 GHz in the direction parallel to the main surface of each of the samples 7-9 and other samples prepared by the two-fluid spray method. tp The relationship between the measurement results and the surface resistance measurement results is shown along with the applied load applied to the two-dimensional structural material film 11.

[0062] Table 1 shows the transmission attenuation R at different frequencies for each of the samples 1 to 9. tp The measurement results for both the temperature and the porosity are shown together.

[0063] [Table 1]

[0064] As the load increases from sample 1 to sample 3, from sample 4 to sample 6, and from sample 7 to sample 9, the porosity decreases, and the contact between the graphene powders, which are the conductive filler, becomes denser, thus decreasing the surface resistance. The optimal surface resistance in the 20 to 40 GHz band is assumed to be around 10 Ω, so as shown in Figures 10, 13, and 16, the transmission attenuation rate peaks in samples 2, 5, and 8 at a load of 0.5 tons. As shown in Figure 6, the c-axis orientation is also at its maximum at a load of 0.5 tons, so it is thought that the orientation also contributes to the transmission attenuation rate. In samples 3 and 6, the surface resistance is less than 1 Ω, so the transmission attenuation rate decreases, but improvement in characteristics is expected by reducing the film thickness. In the lower frequency sub-6 GHz band of 3.7 GHz, it is known that the optimal surface resistance shifts to the low resistance side, and as shown in Figure 10, the maximum transmission attenuation rate was obtained in samples 3, 6, and 9, which have small porosity and low surface resistance.

[0065] Furthermore, the transmission attenuation rate, which is the electromagnetic wave absorption characteristic of conductive noise suppression sheets in the near field, is known to vary with surface resistance, and there is a surface resistance for each frequency band that yields the maximum transmission attenuation rate. As shown in the relationship between surface resistance and transmission attenuation rate in Figure 8, etc., if the surface resistance is 1 × 10⁻⁶ 3 When the resistance exceeds Ω, the transmission attenuation rate for each frequency band decreases significantly, while the surface resistance is 1 × 10⁻⁶. 3 It was found that the maximum transmission attenuation rate can be obtained when the impedance is less than or equal to Ω.

[0066] (Near-field measurement) The near-field electromagnetic shielding characteristics were measured using the microstrip line method. Figure 19 shows the transmission attenuation rate R of the signal when a signal was passed through a microstrip line simulating an electronic circuit board, with samples 9 and 10 placed spaced apart on its surface. tp The frequency dependence of is shown for each separation distance. Figure 19(A) is a figure for sample 9, and Figure 19(B) is a figure for sample 10. For both samples, when the separation distance exceeds 5 μm, the transmission attenuation rate R tp The transmission attenuation rate R decreases, especially at a separation distance of 30 μm. tpIt was confirmed that the amount of electromagnetic radiation was significantly reduced. Therefore, when the two-dimensional structural material film 11 of the present invention is provided on the electronic device body 12 as an electromagnetic wave shield, it is preferable that the electronic device body 12 and the two-dimensional structural material film 11 are in close contact or within 5 μm of each other with an insulating material in between.

[0067] (Far field measurement) The characteristics of far-field electromagnetic shielding were measured using the free-space method. The two-dimensional structural material film 11 of samples 7 and 9 was measured using the free-space method. 11 Value (reflection coefficient) and S 21 The values ​​(transmission coefficient) were measured using a network analyzer (EM Labs). Figure 20 shows the S of the two-dimensional structural material film 11 of samples 7 and 9. 11 Value (reflection coefficient) and S 21 The frequency characteristics of the value (transmission coefficient) are shown. Figure 20(A) is for sample 7, and Figure 20(B) is for sample 9. The shielding effect of electromagnetic waves is the transmission coefficient S. 21 This is determined solely by the transmission coefficients of samples 7 and 9, which are both below -10 dB. This indicates that the two-dimensional structural material film 11 of the present invention has electromagnetic shielding performance even in the far field.

[0068] (Application fields of the present invention) The two-dimensional structural material film 11 according to the present invention may be used as a radio wave absorbing material in the frequency band of 10 to 40 GHz. It can be applied to technologies such as 5G / 6G mobile communications, intelligent transportation systems (ITS), wireless LANs, and electronic medical devices (cardiac pacemakers, cochlear implants, etc.) to prevent external interference. It can also be applied to technologies such as stabilizing the operation inside electronic devices. Examples of electronic devices include internal electronic devices in railways, automobiles, ships, aircraft, and satellites (various sensors such as radar systems, communication equipment, batteries, motors, power lines, navigation systems, attitude control systems, etc.), household electronic devices such as TVs, office automation equipment, computers, and game consoles, and industrial and research electronic devices such as measuring devices and experimental equipment. The two-dimensional structural material film 11 according to the present invention can also be used to improve the efficiency of antenna signal reception accuracy. The two-dimensional structural material film 11 according to the present invention can also be used to prevent skimming of credit cards and IC cards. The two-dimensional structural material film 11 according to the present invention can also be used to prevent interference of sensors using electromagnetic waves with security devices. The two-dimensional structural material film 11 according to the present invention can also be used to suppress the external influence of electromagnetic waves in devices that utilize electromagnetic waves, such as particle accelerators, MRI (magnetic resonance imaging) machines, and microwave ovens. The two-dimensional structural material film 11 according to the present invention can also be used to secure a certain space that is shielded from external electromagnetic waves, such as in electromagnetic shielding rooms for operating rooms and laboratories. The two-dimensional structural material film 11 according to the present invention can also be used for stealth equipment, such as avoiding radar detection by absorbing or blocking electromagnetic waves. The two-dimensional structural material film 11 according to the present invention can be used as a sound-absorbing material because it can convert sound energy into thermal energy by vibrating the voids by adjusting the porosity. It can also be used to secure a certain space that is shielded from external electromagnetic waves, such as in electromagnetic shielding rooms for operating rooms and laboratories. Since a high transmission attenuation rate can be obtained in the millimeter-wave band of 30 GHz or higher, it may be used as a millimeter-wave compatible conductive noise suppression sheet to replace conventional magnetic noise suppression sheets.The two-dimensional structural material film 11 according to the present invention may be used as a heat dissipation / heat dispersion material for heat exchangers, such as a heat dispersion sheet for electronic elements in smartphones and mobile devices. The two-dimensional structural material film 11 according to the present invention may be used as an electrode material for batteries such as lithium-ion batteries, lithium-air batteries, dye-sensitized solar cells, and supercapacitors. The two-dimensional structural material film 11 according to the present invention exhibits a gauge factor of 100-200, similar to that of semiconductors, and may be used as a pressure / strain sensor such as a biological monitor (pulse / blood pressure) or motion sensor. [Explanation of symbols]

[0069] 1‥Two-dimensional structural material particles 2‥Void 10‥Electronic equipment 11‥2D structure material film 12‥Electronic device body 13. Insulating material.

Claims

1. It is composed of two-dimensional structural material particles and a water-soluble binder. The c-axis orientation of the two-dimensional structural material particles falls within the range of 70-100%. The mass ratio of the two-dimensional structural material particles to the total mass of the two-dimensional structural material particles and the water-soluble binder is in the range of 80 to 98 wt%. The porosity falls within the range of 13-67%. The aforementioned two-dimensional structural material particles are graphene, in which the integrated intensity ratio I / G of the D-band and G-band of the Raman spectroscopic spectrum is less than 1.

0. A two-dimensional structural material film with electromagnetic wave absorption and shielding properties.

2. In the two-dimensional structural material film according to claim 1, The porosity is within the range of 18-50%. Two-dimensional structural material film.

3. It is composed of two-dimensional structural material particles and a water-soluble binder. The c-axis orientation of the two-dimensional structural material particles falls within the range of 70-100%. The mass ratio of the two-dimensional structural material particles to the total mass of the two-dimensional structural material particles and the water-soluble binder is in the range of 80 to 98 wt%. Surface resistance is 1 × 10 3 It is less than or equal to Ω, The aforementioned two-dimensional structural material particles are graphene, in which the integrated intensity ratio I / G of the D-band and G-band of the Raman spectroscopic spectrum is less than 1.

0. A two-dimensional structural material film with electromagnetic wave absorption and shielding properties.

4. In a two-dimensional structural material film according to any one of claims 1 to 3, The thickness is within the range of 1 to 200 μm. Two-dimensional structural material film.

5. An electronic device comprising a two-dimensional structural material film according to any one of claims 1 to 3, and an electronic device body, The two-dimensional structural material film and the electronic device body are arranged with a thickness of 5 μm or less, either in close contact or with an insulating material in between. electronic equipment.

6. A method for manufacturing a two-dimensional structural material film according to any one of claims 1 to 3, A step of preparing a raw material liquid so that the mass ratio of two-dimensional structural material particles to water is in the range of 5 to 20 wt%, and the mass ratio of two-dimensional structural material particles to the total mass of the two-dimensional structural material particles and the water-soluble binder is in the range of 80 to 98 wt%, The process involves applying the raw material liquid onto a substrate according to a two-fluid spray method, and then heating the raw material liquid to remove the water from the raw material liquid to form an interlayer film. The process includes a step of applying a load of 0.5 to 5.0 t in the thickness direction to the interlayer film for 1 second to 60 minutes. A method for manufacturing a two-dimensional structural material film.

7. A method for manufacturing a two-dimensional structural material film according to claim 1, A step of preparing a raw material liquid so that the mass ratio of two-dimensional structural material particles to water is in the range of 5 to 20 wt%, and the mass ratio of two-dimensional structural material particles to the total mass of the two-dimensional structural material particles and the water-soluble binder is in the range of 80 to 98 wt%, The process involves applying the raw material liquid onto a substrate according to a jet dispensing method, and then heating the raw material liquid to remove the water from the raw material liquid to form an interlayer film. The process includes a step of applying a load of 0.5 to 5.0 t in the thickness direction to the interlayer film for 1 second to 60 minutes. A method for manufacturing a two-dimensional structural material film.

8. A method for manufacturing a two-dimensional structural material film according to claim 3, A step of preparing a raw material liquid so that the mass ratio of two-dimensional structural material particles to water is in the range of 5 to 20 wt%, and the mass ratio of two-dimensional structural material particles to the total mass of the two-dimensional structural material particles and the water-soluble binder is in the range of 80 to 98 wt%, The process involves applying the raw material liquid onto a substrate according to a jet dispensing method, and then heating the raw material liquid to remove the water from the raw material liquid to form an interlayer film. The process includes a step of applying a load of 0.5 to 5.0 t in the thickness direction to the interlayer film for 1 second to 60 minutes. A method for manufacturing a two-dimensional structural material film.

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