JP2005254393A - Continuous fiber fullerene thin line and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a producing technology of continuous fiber fullerene thin wire having various uses, such as catalyst/filter/gas adsorption material, lightweight nano wiring material, resin composite materia, ion exchange resin, fullerene shell tube producing material, and heating thin line. <P>SOLUTION: In order to obtain a carbon thin line composed of the fullerene, the manufacturing method of the fullerene thin line includes (1) a step for mixing a solution including a first solvent dissolving the fullerene and a second solvent having smaller dissolving performance of the fullerene than the first solvent; (2) a step for forming a liquid-liquid interface between the solution and the second solvent; (3) a step for depositing the carbon thin line on the liquid-liquid interface. At least one kind selected from a group of alkali metal, alkaline earth metal element, hydroxide of alkali metals or alkaline earth metal element, alkoxide, another organic/inorganic compound is added to the second solvent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a fullerene-based carbon material, in particular, a long fiber fullerene fine wire and a method for producing the same.

Fullerene fine wires (fullerene nanowhiskers, fullerene nanofibers) have recently attracted attention in domestic and overseas research institutes, private companies, and universities, and development competition is intensifying.

The present inventors have previously developed a method for producing a fullerene fine wire using a liquid-liquid interface precipitation method (Patent Document 1, Non-Patent Document 1, Non-Patent Document 2).

In this method, when obtaining a carbon fine wire having fullerene as a constituent element, (1) a solution containing a first solvent in which fullerene is dissolved, and a second solvent having a lower fullerene solubility than the first solvent. A method of producing a carbon fine wire, including a step of combining, (2) a step of forming a liquid-liquid interface between the solution and the second solvent, and (3) a step of depositing a carbon fine wire at the liquid-liquid interface. It is. Moreover, the present inventors have clarified that growth is remarkably promoted by irradiating visible light during the growth of fullerene fine wires (Non-patent Document 3).

Japanese Patent Laid-Open No. 2003-1600 K.Miyazawa, Y.Kuwasaki, A.Obayashi and M.Kuwabara, “C60 nanowhiskers formed by the liquid-liquid interfacial precipitation method”, J. Mater. Res., 17 [1] (2002) 83-88 Junichi Miyazawa, “Fullerene Nanowhiskers”, Industrial Materials, 52 [1] (2004) 24-25 M. Tachibana, K. Kobayashi, T. Uchida, K. Kojima, M. Tanimura and K. Miyazawa, “Photo-assisted growth and polymerization of C60`nano'whiskers”, Chemical Physics Letters 374 (2003) 279-285

Long fiber fullerene thin wires have a wide range of applications such as catalysts, filters, gas adsorbing materials, lightweight nanowiring materials, resin composite materials, ion exchange resins, fullerene shell tube fabrication materials, and exothermic thin wires. An object of the present invention is to provide a technique for producing a long-fiber fullerene fine wire in order to accelerate the practical use of these applications.

The present inventors have clarified that the growth of fullerene fine lines is significantly promoted by light when producing fullerene fine lines using the liquid-liquid interface precipitation method developed by the present inventors. It has been discovered that the addition of a trace amount of an alkali metal or alkaline earth metal element to the second solvent having a lower ability to dissolve fullerene than the first solvent has a great effect on growth.

That is, the present invention is selected from the group consisting of alkali metal elements, alkaline earth metal elements, hydroxides of alkali metal elements or alkaline earth metal elements, alkoxides, and other organic / inorganic compounds as the second solvent. Production of fullerene fine wire by liquid-liquid interface deposition method using an alcohol solution such as isopropyl alcohol in which at least one kind is dissolved and an organic solution such as toluene and metaxylene in which fullerene molecules such as C ₆₀ and C ₇₀ are dissolved. Is the method.

An alcohol solution such as isopropyl alcohol was added alone or compounds containing those alkali metal or alkaline earth metal element, the liquid in the system of the organic saturated solution such as toluene or xylene in the C ₆₀ and C ₇₀ - liquid interface A method for producing fullerene fine wires by a precipitation method is an unprecedented method.

The reason why the growth of fullerene fine wires is remarkably promoted when an appropriate concentration of alkali metal or alkaline earth metal element is added to the second solvent is considered as follows. C ₆₀ is because it has a high electron affinity, the charge transfer from easily element emits electrons, it is possible to change the charge state of C _60. Change in the electron density around C ₆₀ molecules, will affect the state of the chemical bond between C ₆₀ molecules, it affects the growth mechanism of thin lines occurs.

Thus, the addition of alkali metal or alkaline earth metal to the second solvent is C _60.
This influences the growth of thin wires, and the present invention is based on the principle of natural phenomena. A similar mechanism applies to the growth of higher-order fullerene fine wires of C ₇₀ and higher. The present invention
This suggests that electron donation by alkali and alkaline earth metal elements is strongly related to the growth mechanism of fullerene fine wires.

By the method of the present invention consists of C ₆₀ and C ₇₀ molecules, etc., it is possible to obtain the length of fullerene thin wires centimeter order of millimeters. By this method, it is possible to produce a fullerene fine line that is several times to one digit longer than that of the prior art.

The liquid-liquid interface deposition method developed by the present inventors is as follows.
(1) A step of combining a solution containing a first solvent in which fullerene is dissolved with a second solvent having a lower ability to dissolve fullerene than the first solvent in obtaining a carbon fine wire having fullerene as a constituent element. 2) forming a liquid-liquid interface between the solution and the second solvent;
3) including a step of precipitating carbon fine wires at the liquid-liquid interface.

In the second solvent, alkali metal element, alkaline earth metal element, hydroxide of alkali metal element such as potassium hydroxide and sodium hydroxide, alkali metal alkoxide such as potassium methoxide, calcium hydroxide, etc. It is characterized by adding at least one selected from the group consisting of alkaline earth metal hydroxides, alkaline earth metal alkoxides, other alkali metal elements or organic / inorganic compounds of alkaline earth metal elements.

A preferable addition concentration is 10 ⁻⁴ to 10 ⁻⁷ mol / L, a preferable liquid temperature is in the range of 5 ° C. to 25 ° C., and a preferable atmosphere is air or an inert gas. The most preferable conditions for the long fiber are that the liquid temperature is 15 ° C. to 25 ° C., and the concentration of alkali and alkaline earth metal elements is 1 × 10
^{It is −5} mol / L to 1 × 10 ⁻⁶ mol / L. When an alkali metal and an alkaline earth metal element are added to the second solvent at a high concentration, C60 fine wires cannot be grown.

When potassium is dissolved in isopropyl alcohol in the form of KOH and added, about 5x10 ^-3 mol /
When the concentration exceeds L, particulate C60 precipitates are formed, and C60 fine wires of long fibers cannot be obtained. As shown in the TEM photograph of FIG. 4, precipitates obtained by the liquid-liquid method with a saturated solution of C60 metaxylene using IPA with a concentration of 9.9 × 10 ⁻³ mol / L are spherical particles and irregular rod-like shapes. This was a precipitate.
In addition, at a concentration of 10 ⁻⁸ mol / L or less, the effect of causing long fiber formation is not observed because the concentration is too small.

The first solvent is a good solvent for fullerene, and the second solvent is a poor solvent for fullerene. The first solvent is a nonpolar solvent and the second solvent is a polar solvent. The first solvent is a hydrocarbon solvent. The hydrocarbon solvent is composed of at least one substance selected from the group consisting of toluene, xylene, benzene, hexane, pentane, carbon disulfide, and derivatives thereof. The second solvent is an alcohol solvent. The alcohol solvent comprises at least one alcohol selected from the group consisting of pentanol, butyl alcohol, isopropyl alcohol, n-propyl alcohol, methyl alcohol, ethyl alcohol, and polyhydric alcohol. In the first step, a metal catalyst or a metal oxide catalyst may be added.

<Example when potassium hydroxide (KOH) is used as the potassium source>
Fullerene fine wires were grown with the solution compositions shown in (a) to (e) of Table 1. A saturated solution of C ₆₀ in toluene (first solvent) (approximately 2.2 gL ⁻¹ ) is added to a suitably sized glass vial (preferably with a volume of 5
pour into isopropyl alcohol (second solvent) with approximately the same amount of KOH at room temperature (5 ° C to 25 ° C) using a pipette, or gently transfer it to the bottle wall. As a result, the mixture was poured to form a liquid-liquid interface between a C ₆₀ metaxylene solution and isopropyl alcohol. The glass bottle was allowed to stand at about room temperature (15 ° C. to 25 ° C.) for about 2 weeks or more. During this time, C ₆₀ wires (C ₆₀ nanowhiskers) grew. Above process was carried out similarly for manufacturing the C ₇₀ thin line (C ₇₀ nanowhiskers).

In the IPA system with 10 ^-3 molL ^-1 concentration of KOH as the solute, C ₆₀ fine wire did not grow, but 10 ^-5 ~
In the system of KOH-IPA with a concentration of 10 ⁻⁶ molL ⁻¹ , C ₆₀ wires that grew remarkably long were obtained. In (f) and (g) to which a small amount of CH ₃ OK was added, long-fiber C ₆₀ fine wires were grown. Added a small amount of KOH
(d) and in (e), C ₇₀ thin line of the long fibers are grown.

<Example when CH ₃ OK is used as potassium source>
Fullerene fine wires were grown with the solution compositions shown in (f) to (G) of Table 1. CH ₃ OK as solute and IPA-
A solution using ₃ wt% CH ₃ OH as a solvent was prepared. In the same manner as in (1), C ₆₀ fine wires were grown by liquid-liquid interface deposition using an IPA-3 wt% CH ₃ OH solution to which a small amount of CH ₃ OK was added and a C ₆₀ saturated toluene or meta-xylene solution. . Long-fiber C ₆₀ thin wires were grown.

<Example using Ca (OH) ₂ as the calcium source>
An IPA solution of Ca (OH) ₂ was prepared, and C ₆₀ fine wires were grown by a liquid-liquid method using this and a saturated solution of C ₆₀ metaxylene. Long-fiber C ₆₀ thin wires were grown.

<Example when NaOH is used as the sodium source>
An IPA solution of NaOH was prepared and C ₆₀ wires were grown by a liquid-liquid method using this and a saturated solution of C ₆₀ metaxylene. Long-fiber C ₆₀ thin wires were grown.

<Observation example of long fiber C ₆₀ fine wire>
Figure 1 (a), C ₆₀ thin line KOH were prepared in a xylene saturated solution of 10 ^-5 molL ^-1 dissolved IPA and C ₆₀ of Example 1 (b), in FIG. 1 (b), carried out 10 ^-5 molL ^-1 of Ca (OH) ₂ of Example 3 was dissolved
The C ₆₀ fine wire prepared with IPA and a saturated solution of C ₆₀ metaxylene, FIG. 1 (c) shows the NaOH of Example 4.
Shows a scanning electron microscope (SEM) image of a C ₆₀ fine wire prepared from IPA in which 10 ^-5 molL ^{-1 is} dissolved and a saturated solution of C ₆₀ metaxylene. It can be seen that both have grown as C ₆₀ fine wires on the order of millimeters.

FIG. 2 shows an enlarged view of each sample in FIG. It has been shown to favorably grown C ₆₀ thin line. FIG.
An X-ray diffraction pattern of a C ₆₀ thin wire prepared by a liquid-liquid method using a saturated solution of C ₆₀ metaxylene in Example 1 (d) and IPA added with 10 ⁻⁵ mol L ^{−1 of} KOH. Show. As is clear from the diffraction pattern, C ₆₀ fine wires with good crystallinity are obtained.

The long fiber fullerene fine wire obtained by the method of the present invention is a remarkable advantage that it is easy to handle, such as fuel cell catalyst support material, photosensitized solar cell, filter, ion exchange column filler, antibacterial material, composite fiber material, etc. When used in the environment, textile, semiconductor and pharmaceutical industries, it is expected to produce significant economic effects.

1 (a) is, in Example 1 (b), FIG. 1 (b), Example 3, FIG. 1 (c), Example 4 C ₆₀ thin line drawing-substituting SEM manufactured by (SEM ) It is a SEM image substituted for an enlarged drawing of the sample shown in FIG. 2 is an X-ray diffraction pattern of a C ₆₀ thin line produced according to Example 1 (d). FIG. 3 is a drawing-substitute TEM photographic image of a precipitate obtained by a liquid-liquid method with a saturated solution of C ₆₀ metaxylene using IPA having a KOH concentration of 9.9 × 10 ⁻³ .

Claims (4)

(1) A step of combining a solution containing a first solvent in which fullerene is dissolved with a second solvent having a lower ability to dissolve fullerene than the first solvent in obtaining a carbon fine wire having fullerene as a constituent element. 2) forming a liquid-liquid interface between the solution and the second solvent;
3) In the method for producing fullerene fine wires, including the step of depositing carbon fine wires at the liquid-liquid interface,
At least one selected from the group consisting of alkali metal elements, alkaline earth metal elements, hydroxides of alkali metal elements or alkaline earth metal elements, alkoxides, and other organic / inorganic compounds is added to the second solvent. A method for producing a long-fiber fullerene fine wire. The method for producing a long-fiber fullerene fine wire according to claim 1, wherein the concentration to be added is 10 ⁻⁴ to 10 ⁻⁷ mol / L. 2. The long fiber fullerene fine wire according to claim 1, wherein the first solvent dissolving the fullerene is an organic solution such as toluene or metaxylene solution, and the second solvent is an alcohol solution such as isopropyl alcohol. Method. A long fiber fullerene fine wire produced by the method according to claim 1.

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