JP4544530B2 - CNT array material manufacturing method - Google Patents

Description

The present invention relates to the production how the CNT array material that can be used, such as in a variety of composite materials.

  In recent years, materials in which fibrous materials are arranged have been developed and used in various applications. For example, as one of the materials in which fibrous materials are arranged, there is a carbon nanotube (hereinafter sometimes referred to as CNT). In order to make use of the high aspect ratio characteristic of this CNT, a method and apparatus for controlling the arrangement using a magnetic field, a molded article of CNTs arranged using these methods and apparatuses, and the like are disclosed ( For example, see Patent Documents 1 to 3 below).

JP 2004-234865 A JP 2002-273741 A Japanese Patent Laid-Open No. 2004-255600

However, those of each of the above documents can not be arranged CNT only substantially along the field direction, there is a problem of strength was low squirrel Runado, applications were limited. In addition, other fibrous materials have the same problem.

The present invention was made in view of the above problems, and an object thereof is application to provide a manufacturing how broad CNT array material.

Means and effects for solving the problems

  The method for producing an array material of fibrous materials according to the present invention includes a length adjusting step for adjusting the fibrous material to a predetermined length, and a fibrous material adjusted in the length adjusting step is mixed in a solvent. A mixing step for obtaining a solution in which the fibrous material is dispersed, and an appropriate amount of the solution obtained in the mixing step is dropped onto the substrate, and a magnetic field is applied to the substrate so that the fibrous material is in a weightless state. And evaporating the solvent in the solution so as to converge the fibrous material. In the mixing step, it is preferable that the fibrous material is uniformly dispersed.

According to the above configuration, the strength is high even those manufacturing is possible applications can provide a method for producing a sequence materials of a wide range of fibrous materials.

  In the method for producing an array material of fibrous materials according to the present invention, it is preferable that the mixing step further includes a step of removing the aggregated fibrous material from the solution. As a result, the aggregated fibrous material, which is difficult to be arranged in the intended configuration, is removed in advance, so that the arranged material of the fibrous material arranged more accurately can be manufactured.

In the method for producing an array material of fibrous materials according to the present invention, it is preferable that the substrate is installed at an angle of 0 to 90 ° with respect to the magnetic field applied in the vertical direction. As a result, a fibrous material bundle is formed as a bundle in which a plurality of fibrous materials are arranged substantially parallel to each other while the major axis direction of the fibrous material is oriented parallel to the magnetic field in the magnetic field direction. Can be arranged such that a plurality of fibrous material bundles are folded over after the direction of the magnetic field becomes parallel to the direction of the magnetic field. As a result, the strength can be produced what is not high in applications can be easily manufactured arrangement materials of a wide range of fibrous materials. Note that it is easily manufactured arrangement materials angles can produce the most strength is not high may be 90 ° and applications extensive fibrous material between the magnetic field and the substrate.

In the method for manufacturing an array material of fibrous materials according to the present invention, it is preferable that the fibrous material is CNT, and the length adjusting step includes a step of sorting into CNTs having a length of 1 μm or more. Accordingly, high strength, thermal conductivity, making those excellent in conductivity can be application capable of producing a sequence material broad CNT.

  The array material of fibrous materials according to the present invention forms a bundle of fibrous materials by forming a bundle of a plurality of fibrous materials that are substantially parallel to each other, and further forms a network thin film structure by folding a plurality of bundles of the fibrous materials. It is characterized by that. From another point of view, the array material of fibrous materials according to the present invention forms a bundle of fibrous materials by forming a bundle of a plurality of fibrous materials in a substantially parallel manner, and the plurality of fibrous material bundles are further folded. A thin film structure having a plurality of holes is formed.

According to the above configuration, the strength is high even those manufacturing is possible applications can provide an array material of a wide range of fibrous materials.

In the fibrous material array material according to the present invention, the fibrous material is preferably a carbon nanotube. Accordingly, high strength, thermal conductivity, making those excellent in conductivity is possible applications can provide an array material broad CNT.

  Hereinafter, embodiments of the CNT array material according to the present invention will be described. First, a method for producing a CNT array material will be described.

  First, single-walled CNTs are cut and sorted into those having a length of 1 to 10 μm by filtration using chromatography or a membrane filter. This selected CNT is mixed with a solvent such as water to prepare a solution. At this time, it is preferable to remove aggregated CNTs in the solution by performing filtration using a centrifugal separator or a membrane filter. Next, after dropping an appropriate amount of this solution onto the substrate, a predetermined magnetic field application device such as a superconducting magnet device can generate a strong magnetic field so that the CNTs in the dropped solution are in a weightless or almost weightless state. The solvent in the solution dropped on the substrate is evaporated while being placed at a position and applying a magnetic field. By such a method, the CNT array material according to this embodiment can be obtained.

  The CNT array material obtained by the above method is a thin film, and a plurality of CNTs are bundled almost in parallel to form a plurality of bundled CNTs, and these bundled CNTs form a network structure. Are arranged. In other words, it can be said that this CNT array material is a porous thin film.

  The CNT array material according to the present embodiment is high in strength, excellent in thermal conductivity and conductivity, can be manufactured in a large area, and can provide a wide range of CNT array materials. Note that this CNT array material further has the ability to adsorb gas such as hydrogen.

  Next, examples of the CNT array material according to the present invention will be described. First, a method for producing the CNT array material of this example will be described. Single-walled CNT was used as a raw material. Hereinafter, it demonstrates in order of a process.

[CNT cutting]
0.01163 g of single-walled CNTs were added to a mixed acid of H ₂ SO ₄ : HNO ₃ = 3: 1 = 30 mL: 10 mL and cut by ultrasonic irradiation. The time and frequency of ultrasonic irradiation are 15 minutes at 25 kHz. About 100 ml of distilled water was added to this, and it filtered with a 0.2 micrometer filter. After filtration, the obtained cut CNT powder was washed with an aqueous NaOH solution until neutral.

[Sort by CNT length]
Sepadex G-50 was used as size exclusion chromatography. First, the cut CNTs were well dispersed in 10 ml of distilled water. Then, since it became a black-gray solution, only the supernatant liquid was taken out well and chromatographed. In addition, the solution eluted earlier with the eluate separated by chromatography is sample 1 (average length of CNT 0.7 μm), and the solution eluted later is sample 2 (average length of CNT 1.. 2 μm).

[Drying on the substrate while applying a magnetic field]
Samples 1 and 2 are respectively dropped onto a mica substrate (for atomic force microscope (AFM)), and a magnetic field is applied in the magnetic field generation region of the superconducting magnet apparatus shown in FIG. 1A (FIG. 1B). Reference) Each substrate was aligned with CNTs while drying the solvent.

  In the schematic diagram of the superconducting magnet apparatus of FIG. 1A, 1 is a superconducting magnet inner cylinder, 2a, 3a, 4a are substrates, 2b, 3b, 4b are substrates for mounting substrates 2a, 3a, 4a, respectively. The mounting table 5 is a nonmagnetic support bar for fixedly supporting the mounting tables 2b, 3b, and 4b. Further, the superconducting magnet device used in the present embodiment uses a superconducting coil whose central axis is the vertical direction, and the inner cylinder 1 is concentrically installed inside the superconducting coil. Although not shown, this superconducting coil is cooled and excited by liquid helium in a cryostat used in a general superconducting magnet device. Samples 1 and 2 are, in the schematic diagram of the superconducting magnet device in FIG. 1A, respectively, an upper position (non-gravity state), a center position (state where the magnetic field strength is maximum (15T)), and a lower position ( The CNTs were oriented by placing them at each position in a 2G hypergravity state.

Next, the alignment results of CNT in samples 1 and 2 will be described. FIG. 2 is an AFM photograph of CNTs aligned at the upper position, the center position, and the lower position of the sample 1. 3, 4, 5, and 6 are AFM photographs shown at the left end, the second from the left, the second from the right, and the right end of the upper position in FIG. 7, (a) is an AFM photograph of CNT oriented in a position on the sample 1, is a graph showing the cross-sectional height information of the CNT in the line as described in (b) is (a). FIG. 8 shows AFM photographs of CNTs oriented at the upper position, the center position, and the lower position of the sample 2. 9, 10, 11, and 12 are AFM photographs shown at the left end, the second from the left, the second from the right, and the right end of the upper position in FIG. FIG. 13A is an AFM photograph of CNT oriented at the upper position of the sample 2, and FIG. 13B is a graph showing information on the cross-sectional height of the CNT along the line described in FIG.

<Result of sample 1>
As shown in FIGS. 2 to 6 , the CNT of the upper sample 1 that is in a weightless state is formed by bundling a plurality of CNTs almost in parallel to form a plurality of bundled CNTs, and these bundled CNTs form a network structure. It can be seen that the CNT array material arranged in an overlapping manner is formed as configured. On the other hand, it was difficult to say that the CNTs of the sample 1 at the center position or the lower position constitute an arrayed structure. Further, as shown in FIG. 7 , the height of the CNT of the CNT array material formed at the upper position in a weightless state is ± 5 nm or less, and thus a plurality of single-walled CNTs are bundled. it is conceivable that. Note that corresponds reverse triangle inverted triangles and 7 (b) in in FIG. 7 (a). Further, FIG. 7 (a) shows what the right pictures with the same portion of the upper position of FIG.

<Result of sample 2>
As shown in FIGS. 8 to 12 , the CNT of the upper sample 2 that is in the weightless state is formed by bundling a plurality of CNTs into a bundle almost in parallel to form a plurality of bundled CNTs, and these bundled CNTs form a network structure. It can be seen that the CNT array material arranged in an overlapping manner is formed as configured. On the other hand, it was difficult to say that the CNTs of the sample 2 at the center position or the lower position constitute an arrayed structure. Further, as shown in FIG. 13 , the height of the CNT of the CNT array material formed at the upper position in a weightless state is ± 8 nm or less, so that a plurality of single-walled CNTs are bundled. Conceivable. Note that corresponds reverse triangle inverted triangles and 13 in (b) in FIG. 13 (a). Further, FIG. 13 (a) shows that of the right edge of the photograph and the upper portion of the position in FIG.

<Summary>
Comparing the results of Samples 1 and 2, it can be seen that when the length of the cut CNT exceeds 1 μm, a high degree of arrangement organization is possible.

Next, the sample 2 was used to verify how the orientation of the CNTs changes depending on the relationship between the magnetic field and the substrate tilt. Specifically, as shown in FIG. 14 , the substrate 6 is placed on the inclined plate 7, and the substrate 6 is placed at a predetermined angle (θ = 90 °, 60 °) with respect to the external magnetic field using the mounting table 8 and the support rod 9. In the same manner as in the case of FIG. 1, the orientation state of CNTs in the vertical magnetic field was examined at the upper, center, and lower positions. At this time, the magnetic field points were appropriately adjusted so as not to shift, and a CNT array material was obtained in the same manner as the alignment method in the case of Samples 1 and 2 above. The results are shown in FIG 15,19,23. FIGS. 16, 17 and 18 show AFM photographs of the left end, the second from the left, and the right end in the upper position of FIG. 20, 21 and 22 show AFM photographs at the left end, the second from the left, and the right end in the upper position of FIG. 24, 25, and 26 show AFM photographs of the left end, the second from the left, and the right end of the upper position in FIG.

15 to 26 , it can be seen that the CNTs are oriented in the substrate at the upper position in any case. Further, it can be seen that the CNTs are highly arrayed as the angle θ increases with respect to the magnetic field (in the order of FIGS. 23 , 19 , and 15 ).

  The present invention can be changed in design without departing from the scope of the claims, and is not limited to the above-described embodiments and examples. As a representative of the present invention, CNT has been described in detail above. However, glass fiber, metal fiber, semiconductor fiber, ceramic fiber, carbon fiber, biological material (DNA, polypeptide, protein), polymer, etc. are the same as CNT. A high degree of sequence organization is possible.

  The present invention can be applied to the production of conductive composite materials (such as antistatic materials, electrostatic discharge materials, and conductive plastics) and strength-enhancing composite materials (such as bulletproof products). Further, the present invention can also be applied to fuel cells, solar cells, thermally conductive composite materials (such as electronic component packages), and electronic devices (such as electronic material wiring).

(A) is the schematic which shows the relationship between the superconducting magnet apparatus and board | substrate etc. which are used for the Example which concerns on this invention, (b) is distribution of the magnetic field intensity in the magnetic field generation region of the superconducting magnet apparatus shown by (a). It is a graph to show. 3 is an AFM photograph of CNTs oriented at the upper position, the center position, and the lower position of Sample 1. FIG. 3 is an AFM photograph shown at the left end of the upper position in FIG. 2. 3 is an AFM photograph shown second from the left in the upper position of FIG. 2. 3 is an AFM photograph shown second from the right in the upper position of FIG. 2. 3 is an AFM photograph shown at the right end of the upper position in FIG. 2. (A) is an AFM photograph of CNT oriented at the upper position of sample 1, and (b) is a graph showing information on the cross-sectional height of the CNT in the line described in (a). 4 is an AFM photograph of CNTs aligned at the upper position, the center position, and the lower position of sample 2. FIG. It is an AFM photograph shown at the left end of the upper position in FIG. FIG. 9 is an AFM photograph shown second from the left in the upper position of FIG. 8. FIG. 9 is an AFM photograph shown second from the right in the upper position of FIG. 8. It is an AFM photograph shown at the right end of the upper position in FIG. (A) is an AFM photograph of CNT oriented at the upper position of sample 2, and (b) is a graph showing information on the cross-sectional height of CNT in the line described in (a). It is the schematic of the experimental apparatus used in order to verify how the orientation of CNT changes with the relationship between a magnetic field and the inclination of a board | substrate. FIG. 15 is an AFM photograph of CNTs oriented at an upper position, a center position, and a lower position with θ = 90 ° in the apparatus of FIG. 14 . 16 is an AFM photograph shown at the left end of the upper position in FIG. FIG. 16 is an AFM photograph shown second from the left in the upper position of FIG. 16 is an AFM photograph shown at the right end of the upper position in FIG. FIG. 15 is an AFM photograph of CNTs oriented at an upper position, a center position, and a lower position with θ = 60 ° in the apparatus of FIG. 14 . 20 is an AFM photograph shown at the left end of the upper position in FIG. 20 is an AFM photograph shown second from the left in the upper position of FIG. 19. 20 is an AFM photograph shown at the right end of the upper position in FIG. FIG. 15 is an AFM photograph of CNTs oriented at an upper position, a center position, and a lower position with θ = 45 ° in the apparatus of FIG. 14 . It is an AFM photograph shown at the left end of the upper position in FIG. It is the AFM photograph shown second from the left in the upper position of FIG. It is an AFM photograph shown at the right end of the upper position in FIG.

DESCRIPTION OF SYMBOLS 1 Inner cylinder 2a, 3a, 4a, 6 Substrate 2b, 3b, 4b, 8 Mounting base 5, 9 Support bar 7 Inclined plate

Claims (4)

A length adjusting step for adjusting the carbon nanotube to a predetermined length;
A mixing step of mixing the carbon nanotubes adjusted in the length adjusting step with a solvent to obtain a solution in which the carbon nanotubes are dispersed;
The appropriate amount of the solution obtained in the mixing step was added dropwise to the substrate, while the carbon nanotubes by applying a magnetic field so as to weightlessness, the solvent of the solution was added dropwise to the substrate is evaporated, the carbon nanotube A method for producing a CNT array material, comprising: a step of converging alignment. 2. The method for producing a CNT array material according to claim 1, wherein the mixing step further includes a step of removing the aggregated carbon nanotubes from the solution. The method for producing a CNT array material according to claim 1 or 2, wherein the substrate is installed at an angle of 0 to 90 ° with respect to the magnetic field applied in the vertical direction. Before Sulfur butterfly adjusting step, the manufacturing method of the CNT array material according to any one of claims 1 to 3, characterized in that it comprises the step of selecting a 1μm or more of the length of the carbon nanotubes.