JPH0349938B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a novel organic conductive material. More specifically, the present invention is an organic conductive material that is characterized by adding an inorganic salt or an organic salt to a conjugated polymer compound, molding it, and applying a voltage to the molded product to make it highly conductive. The present invention provides a simple method for producing a flexible material. In recent years, with remarkable technological progress in the electronics industry, there has been an urgent need to develop materials for electronics parts that are suitable for various purposes. 1 of them
Due to their excellent flexibility, processability, and chemical resistance, conductive materials mainly made of organic materials are attracting attention as wiring materials, electrode materials, sensors, photoelectric conversion elements, memory elements, and molecular devices. There is. Conventionally, organic conductive materials have been known, such as polyacetylene, poly(p-phenylene), polyphenylene sulfide, polypyrrole, etc., to which doping components are added, and these have 10 ^-1 to 10 It shows an electrical conductivity of about ^-3 Scm ^-1 , but
Compared to inorganic conductive materials, it is considerably lower and less stable, so it cannot be said to be sufficient for practical use. The present inventors have conducted intensive research on organic conductive materials that can be put to practical use, and first developed a method of adding a doping component to a diacetylene polymer compound as a main component, by polymerizing diacetylene compound crystals in a dopant atmosphere. A polymer crystal having a conductivity of about 10 ^-4 S/cm can be obtained by a doping solid phase polymerization method in which a diacetylene compound is crystallized in the presence of a doping component and the crystal is polymerized. We discovered that a metal conductor of 10 S/cm can be obtained by doping a butadiinyl polymer compound with an electron-accepting compound such as iodine, but we have found that an even easier method for making a conjugated polymer compound highly conductive is as follows: Inorganic salts and organic salts are added to a conjugated polymer compound and molded.
The present inventors discovered a simple method for producing an organic conductive material in which the molded body is made highly conductive by attaching electrodes to both ends of the molded body and applying a voltage, thereby achieving the present invention. That is, the present invention provides polyacetylene, polyphenylene, polynaphthylene, polythienylene, polypyrrole, polycarbazole, polyquinone, polyphenylene vinylene, polycyanoacetylene,
In a conjugated polymer compound selected from polybutadiin, polydiacetylene, poly(acetylene-diacetylene), polyin, polymetalin, polyphenylenebisbenzothiazole, polyoxadiazole, polyazomethine and their derivatives. , general formula MrXs...() [M in the formula is Ag, Cu, Co, Fe, Mn, Cr, Li,
Na, K, Mg, Ca, N(CH ₃ ) ₄ , N(C ₂ H ₅ ) ₄ , N
(C ₃ H ₇ ) ₄ , N(C ₄ H ₉ ) ₄ or N(C ₆ H ₆ ) ₄ , X is Cl,
Br, I, ClO ₄ , BF ₄ , PF ₆ , AsF ₆ , NO ₃ , SbF ₆ ,
At least one doping component selected from the compounds represented by SO ₃ , SO ₄ , SO ₃ C ₆ H ₆ or CO ₃ , r and s are each an integer of 1 to 3].
A method for producing an organic conductive material, which is characterized in that it is added in a proportion of 0.1 to 200% by weight, then molded, and then electrodes are provided at both ends of the molded product and a voltage is applied between them to make it highly conductive. It provides: The conjugated polymer compounds used in the present invention include polyacetylene, polyphenylene, polynaphthylene,
Polythienylene, polypyrrole, polycarbazole, polyquinoline, polyphenylene vinylene, polycyanoacetylene, polybutadiyne, polydiacetylene, poly(acetylene-diacetylene),
It is selected from polyyne, polymetalyne, polyphenylenebisbenzothiazole, polyoxadiazole, polyazomethine, and their derivatives, and is basically a general term for main chain conjugated polymer compounds. This includes various derivatives thereof. Typical examples of these include, for example,
trans-polyacetylene, polyphenylacetylene, poly-p-phenylene, poly-2,5-thienylene, poly-2,6-naphthylene, poly-2,
5-quinone, poly-bis(1,3-pentadiynyl)mercury, poly-1,6-dicarbazoyl-2,
4-hexadiyne, etc. can be mentioned.
These conjugated polymer compounds are usually used as a single component, but two or more types can be used in combination if necessary. Of course, it can be easily inferred that fired polymer compounds obtained by firing these conjugated polymer compounds, aromatic polyamides, aromatic polyimides, etc. can also be used. Further, the compound used as a doping component in the method of the present invention is represented by the above general formula (), and examples of such compounds include AgClO ₄ , AgNO ₃ , CuCl ₂ , LiClO ₄ ,
Inorganic salts such as Na ₂ SO ₄ , MgCO ₃ , N
Organic salts include ( _C2H5 ) _4ClO4 , N( _C4H9 ) _{AsF6 , LiSO3} -Ph, and _{the like} . These doping components may be used alone or in combination of two or more. Methods for adding these doping components to the conjugated polymer compound include simply mixing them, mixing them in a solvent in which the doping components are soluble, and distilling off the solvent. However, any method is acceptable. In addition, the content of doping components per weight of the conjugated polymer compound depends on the required electrical conductivity.
The proportion is selected between 0.1 and 200% by weight. A sample prepared by adding a doping component to a conjugated polymer compound is molded into a pellet using an ordinary tablet molding machine. A molding method such as molding under high pressure of several thousand atmospheres to tens of thousands of atmospheres can be considered, but any method may be used. Methods of providing electrodes at both ends of the molded product include applying a conductive paste such as gold paste, silver paste, or carbon paste, vapor-depositing metal such as gold, silver, or aluminum, or depositing a gold plate, platinum plate, etc.
There is a method such as sandwiching it between silver plates. Methods for applying voltage to such a molded product with electrodes attached at both ends include batteries, stabilized power sources, and the like, and either direct current or alternating current may be used. The voltage is appropriately selected from several millivolts to several tens of volts. As the conductivity of the sample gradually increases, the amount of current that flows increases even when a small voltage is applied, so the applied voltage becomes smaller. The organic conductive material thus obtained by the production method of the present invention has a conductivity of about 10 ^-4 to ^{10 3} S/cm, and is not only stable in general environments such as air, but also It has the characteristic that it is a conductive polymer compound that has already been molded. In other words, according to the manufacturing method of the present invention, high conductivity can be achieved simply by applying a voltage after molding, so if high conductivity is achieved by a normal doping method, the sample will be unstable and must be handled during molding. Highly conductive molded products can be easily obtained even from polymer compounds that are difficult to obtain, such as polyacetylene and polyphenylene. Also,
In conventional doping methods, solid doping components are doped by wet processing, but this manufacturing method is advantageous because it does not require solvents or drying processing, and can be used for various electronic components, electrodes, sensors, photoelectric conversion elements, memory elements, etc. It is suitable as a material for Next, the present invention will be explained in more detail with reference to Examples. Example ₁ 260 mg ( ₁₀ m
207 mg (1m mol) of silver perchlorate (AgClO ₄ ) in
A polyacetylene gel containing AgClO ₄ as a doping component is prepared by mixing in 20 ml of acetone and distilling off the solvent. this sample
100mg was packed into a Teflon capsule, incorporated into Pyroferrite, and placed in a link pressurizer for approx.
By applying high pressure of 100,000 atmospheres for 30 minutes, it was formed into a circular pellet with a diameter of 0.3 cm and a thickness of about 0.4 cm. Silver paste is applied to both sides of the pellet, and a voltage is applied by connecting an ammeter and a stabilized power source using a platinum wire as a lead wire, as shown in FIG. At first, as the voltage is gradually increased,
Since a few microamperes flow at a few volts, the resistance is measured to be about 10 ⁶ Ω, but under a certain voltage, the resistance suddenly decreases, and the voltage required to flow the same current drops. If the voltage is further applied, 1 at 10 mV.
mA began to flow, the resistance was 10Ω, and the conductivity was 1.8x10 ^-3 S/cm. By applying voltage,
Since the conductivity has improved, high voltages cannot be applied under voltage regulations. Therefore, when voltage was continued to be applied with current regulation, the voltage was 0.08 mV at 100 mA, and the conductivity was 225 S/cm. This conductivity is
No change occurred even after being left in the air for more than a month. Example 2 Poly-p-phenylene was synthesized and purified according to a conventional method, and 30% by weight of copper hexafluorophosphate [Cu(PF ₆ ) ₂ ] was added as a doping component.
Add and mix thoroughly in an agate mortar.
50 mg of this sample was packed in a Teflon tube in the same manner as in Example 1, platinum plates were attached to both ends as electrodes, leads were taken with gold foil, and the sample was incorporated into pyroferrite and a pressure of 83,000 atmospheres was applied for 12 hours while applying a voltage of 1V. By applying the mixture, a molded article was obtained. The sample was formed into a circular pellet shape with a thickness of 0.3 cm and a diameter of 0.3 cm, and the conductivity was measured using the two-probe method and found to be 80 S/cm.
It was hot. Example 3 Poly-2,5-thienylene was synthesized and purified according to a conventional method, and 410 mg (5 mmol) of this compound was added with lithium hexafluoroarsenite (LiAsF ₆ ).
196 mg (1 mmol) was added, followed by 30 ml of THF. This suspension is evaporated,
200 mg of this mixture was made into a tablet with a diameter of 1.3 cm and a thickness of 1.3 cm.
It was formed into a circular pellet of 0.04 cm. Electrodes with an area of 0.5 cm ² were attached to both sides using gold paste, and a voltage was applied by flowing a constant current. The relationship between current and conductivity is shown in FIG. This figure shows that in a region where the resistance is relatively high, a jump in conductivity can be seen with the application of 0.5V, and as the resistance decreases and a large current flows, a similar change can be seen with the application of 0.03V. It is shown that. The final conductivity of this sample was 8S/cm. Example 4 25 mg of iron chloride (FeCl ₃ ) was added to 100 mg of polyyne synthesized and purified from butadiine according to a conventional method.
After thoroughly pulverizing and mixing in an agate mortar, the mixture was molded into circular pellets with a diameter of 1.3 cm and a thickness of 0.02 cm using a tablet molding machine. The following operations were performed in the same manner as in Example 3,
The electrical conductivity of the material obtained was 3x10 ^-2 S/cm. Example 5 Bis(2,5-ditrifluoromethylphenyl)butadiine synthesized and purified according to a conventional method was sealed in a vacuum tube and polymerized by 5MR irradiation with γ-rays. To this polydiacetylene, 10% by weight of AgClO ₄ was added as a doping component and thoroughly mixed to obtain powdered polydiacetylene crystals. The following operations were carried out in the same manner as in Example 1, and the electrical conductivity of the obtained material was 0.7 S/cm. Example 6 The same operation as in Example 5 was carried out except that tetrabutylammonium hexafluorophosphate ((C ₄ H ₉ ) ₄ N PF ₆ ) was used as the doping component.
The electrical conductivity of the material obtained was 1x10 ^-4 S/cm. Example 7 Using a polyoxadiazole synthesized and purified according to a conventional method as a conjugated polymer compound and silver nitrate as a doping component, the following operations were carried out as follows:
The same procedure as in Example 1 was carried out. The electrical conductivity of the material obtained was 2x10 ^-4 S/cm. Example 8 Bis(1,3-pentadiynyl)mercury synthesized and purified according to a conventional method was placed in a vacuum sealed tube and γ-rays were emitted.
Polymerization was carried out by irradiating with 10MR. AgClO ₄ is added to this polydiacetylene as a doping component.
was added in an amount of 10% by weight to form a powdered polydiacetylene crystal that was thoroughly mixed. The following operations were performed in the same manner as in Example 2, and the electrical conductivity of the obtained material was 0.5S/cm.
It was hot. Example 9 Silver perchlorate (AgClO ₄ ) was mixed in different proportions to polyacetylene gel synthesized in the same manner as in Example 1, and after molding, a voltage was applied in the same manner as in Example 1 to make the gel conductive. improved the rate. The highest conductivities thus obtained are shown in Table 1.

[Table] Example 10 Polyacetylene and gel synthesized in the same manner as in Example 1 were mixed with various dopants at a ratio of 100% by weight, and after molding, a voltage was applied in the same manner as in Example 1 to determine the conductivity. improved. The highest conductivities thus obtained are shown in Table 2.

[Table] The reason why the conductivity of the organic salts used in this table is low is because they have a lower specific gravity than inorganic salts, and when mixed at the same weight ratio, their volume fraction increases, resulting in a low volume conductivity. In order to become
When added in a small weight ratio, for example, when (C ₂ H ₅ ) ₄ NAsF ₆ is mixed with polyacetylene gel at a ratio of 5% by weight, the conductivity becomes 180 S/cm.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a method of applying a voltage to a sample in the method for producing an organic conductive material of the present invention, in which reference numeral 1 is an electrode, and 2 is a doping method for a conjugated polymer compound. 3 is a stabilized power supply, and 4 is an ammeter. FIG. 2 is a graph showing the change in electrical conductivity with respect to current when voltage is applied at a constant current in the method for producing an organic conductive material of the present invention, and the numbers in the figure represent the electrical conductivity. This shows the potential when the value increases rapidly.

Claims (1)

[Claims] 1 Polyacetylene, polyphenylene, polynaphthylene, polythienylene, polypyrrole, polycarbazole, polyquinone, polyphenylene vinylene, polycyanoacetylene, polybutadiyne, polydiacetylene, poly(acetylene-diacetylene), polyyne, polymetalyne, In the conjugated polymer compound selected from polyphenylene bisbenzothiazole, polyoxadiazole, polyazomethine and their derivatives, the general formula MrXs [M in the formula is Ag, Cu, Co, Fe, Mn ,Cr,Li,
Na, K, Mg, Ca, N(CH ₃ ) ₄ , N(C ₂ H ₅ ) ₄ , N
(C ₃ H ₇ ) ₄ , N(C ₄ H ₉ ) ₄ or N(C ₆ H ₆ ) ₄ , X is Cl,
Br, I, ClO ₄ , BF ₄ , PF ₆ , AsF ₆ , NO ₃ , SbF ₆ ,
SO ₃ , SO ₄ , SO ₃ C ₆ H ₆ or CO ₃ , r and s are each an integer of 1 to 3] 0.1 to 200% by weight of at least one doping component selected from the compounds represented by 1. A method for producing an organic conductive material, which comprises adding the same at a ratio of 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000.