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

Abstract

The present invention provides a two-dimensional structural material film capable of improving functionality derived from two-dimensional structural materials, 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 70-100%, and the porosity is in the range of 13-67%.

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 project] [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 aims to provide a two-dimensional structural material film and a method for manufacturing the same that can improve the functionality derived from the two-dimensional structural material. [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 of the 2D structural material particles falls within the range of 70-100%. It is included in the range of 80 to 98 wt% of 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. The porosity is included in the range of 13 to 67%.

[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%, and is included in the range of 80 to 98 wt% of 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. The surface resistance is 1×10 3 Ω or less.

[0008] The method for manufacturing the two-dimensional structure material film of the present invention includes a step of adjusting a raw material liquid agent so 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 the jet dispensing method or the two-fluid spraying method, and heating the raw material liquid agent to remove the water from the raw material liquid agent to form an intermediate film; and a step of applying a load of 0.5 to 5.0 t in the thickness direction of the intermediate film over 1 sec to 60 min.

[0009] According to the two-dimensional structure material film of this structure, the c-axis orientation degree of the two-dimensional structure material particles is included in the range of 70-100%. Due to the two-dimensionality of its special chemical bonding state, the two-dimensional structure material has extremely high electrical conduction characteristics in the c-plane (a-b plane) compared with the c-axis direction. Therefore, the two-dimensional structure material film can be used as an electromagnetic wave shielding / absorbing material. As a near-field electromagnetic wave absorption sheet in mobile devices such as mobile communication, resin composite sheets of magnetic flattened powders such as Sendust are widely commercialized as noise suppression sheets using magnetic loss. However, the increase in electromagnetic wave utilization bands such as 5G or 6G in recent years and the demand for thin sheets have led to a decrease in magnetic permeability and a reduction in the volume of the magnetic material, resulting in deterioration of electromagnetic wave absorption characteristics. In this regard, the two-dimensional structure material film using conductive loss has improved electromagnetic wave absorption characteristics as the frequency increases and is not affected by the deterioration of characteristics due to volume reduction, so it is much more advantageous than conventional magnetic noise suppression sheets.

[0010] Since the two-dimensional structure material also has extremely high thermal conduction characteristics in the c-plane at the same time, the two-dimensional structure material film can also be used as a heat dissipation or heat dispersion sheet. The fact that the two-dimensional structure material film has both electromagnetic wave absorption / shielding characteristics and heat dispersion / heat dissipation characteristics is advantageous for applications to mobile communication devices and the like where heat generation of electronic devices due to an increase in data processing volume becomes a problem. Similar to carbon nanotubes, the two-dimensional structure material film has a large change in electrical resistance accompanying mechanical deformation and can also be applied as a pressure or strain sensor. Since carbon-based materials have a lower density and can be lightweight compared to inorganic materials such as metals and ceramics, it is advantageous for the above applications.

[0011] Since the porosity of the two-dimensional structure material film is included in the range of 13-67%, an improvement in the volume occupancy rate of the two-dimensional structure material can be achieved. Therefore, an improvement in functions such as electromagnetic wave absorption characteristics derived from the two-dimensional structure material can be achieved.

Brief Description of the Drawings

[0012] [Figure 1] A diagram showing a schematic cross-section of an electronic device as an 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] Diagram illustrating the surface resistance and transmission attenuation rate (3.7 GHz) of the sample. [Figure 9] Diagram illustrating 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] (Construction of a two-dimensional structural material film) 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 concept of 2D structural material particles 1 encompasses not only single-layer 2D structural materials but also multilayer 2D structural material particles in which basal planes overlap. Materials having single-layer or multilayer 2D structures, such as graphene, hexagonal boron nitride (h-BN), TMDs such as MoS2, phosphorene (black phosphorus), and conductive carbides or nitrides such as MXene (maxine), may be used as the 2D structural material. The average diameter of the 2D structural material particles 1 is in the range of 0.1 to 100 μm, preferably 0.5 to 50 μm, more preferably 0.5 to 10 μm, and even more preferably 0.5 to 5 μm. The thickness is in the range of 0.3 to 300 nm (1 to 1000 layers of 2D structural material molecules), preferably 0.3 to 30 nm (1 to 100 layers of 2D structural material molecules), and even more preferably 0.3 to 10 nm (1 to 30 layers of 2D structural material molecules).

[0022] Reduced graphene oxide (rGO) has a large number of defects and high resistance, therefore the integral intensity ratio of the D and G bands of the Raman spectrum, which is a parameter of the graphene defect amount, is I D / I G Preferably, graphene with an integral intensity ratio of less than 1, and more preferably less than 0.5, is used. In particular, if the integral intensity ratio exceeds 2, a problem arises in that the surface resistance value becomes large. Because there is a possibility of superimposing graphene-specific absorption (interband transitions) that differ 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. In addition to unmodified graphene, functionally modified graphene such as amino groups and carboxyl groups may be used. Furthermore, multiple materials may be used as the two-dimensional structural material particle 1. For example, graphene particles with 10 or fewer layers and graphene particles with 10 or more layers may be used as the two-dimensional structural material particle 1.

[0023] Figure 5 shows the integrated intensity ratio I D / I G The relationship with the transmission attenuation rate is shown for each frequency. The transmission attenuation rate is measured by the microstrip method described later. As shown in Figure 5, the integrated intensity ratio I D / I G When it exceeds 1, it has been clarified that the transmission attenuation rate decreases in all frequency bands. As indicated by this, the two-dimensional structure material particles used as raw materials preferably have an integrated intensity ratio I D / I G less than 1.0, which is graphene.

[0024] As the water-soluble binder, for example, cellulose nanofiber (CNF), carboxymethyl cellulose (CMC), sodium carboxymethyl cellulose (CMC-Na), methyl cellulose (MC), hydroxypropyl methyl cellulose (HPMC), hydroxyethyl methyl cellulose (HEMC), polyvinylpyrrolidone (PVP)-based resin, polyvinyl alcohol (PVA)-based resin, water-soluble epoxy resin, and water-soluble urethane resin are adopted.

[0025] As the water-soluble binder, it is preferable to adopt cellulose-based compounds such as CNF with a heat resistance temperature of 200 °C or higher, PVP-based resin, PVA-based resin and / or water-soluble epoxy resin. Due to thixotropy, the precipitation of two-dimensional structure material particles (fillers) is suppressed in cellulose-based compounds, and they are more suitable for film formation according to the jet dispensing method (JD method) or the spray method than PVP and PVA. CNF modified with a polar group such as sulfated CNF (S-CNF) is preferable because aggregation is prevented due to the electrostatic force between fibers, and a solution with good filler dispersibility can be obtained.

[0026] Subsequently, the raw material liquid agent is applied onto the substrate according to the jet dispensing method (JD method). As the jet dispensing method, either a contact method or a non-contact method may be adopted. For example, the non-contact method is adopted.

[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] (Orientation degree) 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 for sample 9, and Figure 19(B) is 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 equipment 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 is within the range of 13-67%. Two-dimensional structural material film.

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 Two-dimensional structural material film.

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. In a two-dimensional structural material film according to any one of claims 1 to 3, The aforementioned two-dimensional structural material particles have an integrated intensity ratio of I between the D-band and G-band of the Raman spectroscopy spectrum. Ｄ / I Ｇ Graphene with a coefficient of less than 1.0 Two-dimensional structural material film.

6. 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.

7. 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.

8. 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.

9. 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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