JPH0619031B2 - Conducting polymer and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a conductive polymer, and more specifically to a conductive polymer in which a polymer compound having an electron conductivity is supported in a polymer having a hydroxyl group. The present invention relates to a polymer and a method for producing the same.

[Prior Art and Its Problems] A large number of compounds having electron conductivity have been studied today due to their industrial necessity and academic interest. In particular, research on polymer compounds having a conjugated double bond represented by polyacetylene is active. However, these polymer compounds having electron conductivity also have problems in that they have insufficient electric conductivity when used industrially, are mechanically weak, and have no moldability as a polymer. Therefore, an object of the present invention is to obtain an electron-conducting polymer having mechanical strength and flexibility, for industrial use.

[Means for solving problems]

As a result of earnest research in view of the above, the present inventors have completed the present invention based on the finding that a polymer compound having electron conductivity is favorably supported by using a specific polymer. That is, according to the present invention, there is provided a conductive polymer in which a polymer compound having electron conductivity is supported in a polymer having a hydroxyl group.

More specifically, there is provided a conductive polymer, wherein a polymer compound having electron conductivity is nonuniformly supported in a polymer matrix having a hydroxyl group.

The polymer having a hydroxyl group of the present invention, specifically, polyvinyl alcohol and its derivatives, a copolymer having a vinyl alcohol unit, for example, hydrolysis of a copolymer of vinyl acetate and ethylene and a hydroxyl group bonded to the main chain. Polymer, or a compound in which a hydroxyl group is bonded to the main chain via an alkyl chain or an aromatic ring, specifically, a polymer of vinylphenols, a copolymer, cellulose and derivatives thereof, such as Cellulose acetate, cellulose diacetate and the like are preferably used. The polymer may have any shape such as a film shape, a sheet shape, a film shape, a thread shape, a fiber shape, and a hollow fiber depending on the purpose of use.

In addition, a membrane material having an asymmetric structure with respect to the membrane cross section, such as a reverse osmosis membrane and an ultrafiltration membrane, which are widely used as a separation membrane, can be preferably used.

In these cases, the polymer compound having electron conductivity can be easily unevenly distributed in the polymer matrix having hydroxyl groups with respect to the cross section of the film.

As the polymer compound having electron conductivity of the present invention, a conventionally known polymer of a compound having electron conductivity is used without any limitation. Specific examples of such a compound having electron conductivity include pyrrole and its derivatives such as N-methylpyrrole and 2-ethylpyrrole.
-Alkylpyrroles, thiophene, derivatives of thiophene such as 3-alkylthiophene, isothianaphthene and its derivatives, indole, azulene, furan, aniline, phenol, benzene, naphthalene, phenylenediamines, acetylene and the like. One or more types are preferably used. Particularly, heterocyclic compounds such as pyrrole, indole, azulene, thiophene, furan and their derivatives, acetylene and the like are preferable. In practice, a compound having electron conductivity having a good affinity with the above-mentioned polymer having a hydroxyl group is used.

In the present invention, the amount of the polymer compound having electron conductivity carried on the polymer having a hydroxyl group depends on the kind of the polymer compound having electron conductivity, and the purpose of use of the polymer obtained in the present invention Depending on the weight of the polymer, it generally varies from 20% to 2 when it is uniformly present.
A range of up to 00% is suitable. That is, when the content is 20% or less, the resulting polymer has insufficient electron conductivity characteristics, sensitivity to humidity and the like, and when it is 200% or more, it has a high mechanical conductivity which is originally weak. The characteristics of the molecular body appear strongly and become brittle. In practice, when the film cross section is nonuniformly present, the above range is applied only to the portion where the polymer having electron conductivity is present. Therefore, the amount of the polymer compound having an electron conductivity with respect to the total weight of the polymer having a hydroxyl group varies depending on the presence of the polymer.

The supporting of the polymer compound having electron conductivity in the polymer having a hydroxyl group of the present invention is achieved by allowing the compound having electron conductivity to exist in the polymer and polymerizing the compound. As the polymerization method, for example, radical generation catalyst, oxidation catalyst, reduction catalyst, electrolytic oxidation, polymerization based on electric energy such as electrolytic reduction, α, β, ionizing radiation such as γ-ray,
Photopolymerization with visible light using X-rays, ultraviolet rays, and photosensitizers,
Plasma polymerization, polymerization by glow discharge, etc. are appropriately selected depending on the purpose and the compound used for the polymerization.

Further, the supported form of the polymer compound having electron conductivity in the polymer having a hydroxyl group of the present invention is more unfavorable than the case where a compound having electron conductivity is uniformly present in the polymer having a hydroxyl group. It is preferable that they exist uniformly. That is, in terms of imparting conductivity to the polymer,
The uniform presence improves the conductivity even more, but the non-uniform presence in the polymer can impart a new function to the polymer. In particular, a polymer film in which a polymer compound having electron conductivity is nonuniformly present in the cross section of the film is useful. For example, the polymer compound having electron conductivity is present only on one side of the polymer film. The form which is present and is almost (or not) present on the other side is most preferable, but not limited thereto. That is, depending on the intended use of the obtained polymer having electrical conductivity, the polymer compound having electron conductivity to be carried exists in various non-uniform forms, for example, the concentration of both sides of the film-like substance is high. , When the central part of the film cross section is low, the central part of the film cross section has a high concentration of the polymer compound having electron conductivity, and when both surfaces are low, the polymer compound having multiple electron conductivity of the film cross section There are various shades, and various modes are effective, such as when the density of one surface of the film is high and the density of the other surface is low, the density of both surfaces is low, and the density of both surfaces is high.

In the conductive polymer of the present invention, it is preferable that a dopant is present together with the polymer compound having electron conductivity in order to impart desired electron conductivity. As the dopan, conventionally known ones are widely used. For example ^{_{ClO - 4, PF - 4,}} AsF - 4, Cl -, F
^-, Br ^-, FeCl _3, styrene sulfonic acid, polystyrene sulfonic acid, a perfluorocarbon sulfonic acid, toluenesulfonic acid, benzenesulfonic acid, rose bengal,
Anthraquinone disulfate, tetra (sulfonyl) porphyrin, tetrasulfophthalcyanine, bathophenanthroline disulfate, bathophenanthrolyl, polyvinylsulfate,
^{_{PtCl 2- 4, AuCl 4, PdCl}} 2- 4, Fe (CN) 3- 6, RuO - 4, MnO 4 is known as such is used without any limitation. The particularly preferably used among these are particular halide ions Cl ^-
Is. The amount of dopant present is preferably 0.001 or more per repeating unit of the polymer having electron conductivity.

Hereinafter, the typical production method of the conductive polymer of the present invention will be specifically exemplified.

(1) When the polymer having a hydroxyl group is a film,
A compound (monomer) having electron conductivity capable of oxidative polymerization, such as pyrrole, thiol, or aniline, a mixture thereof, or a monomer and a solvent is brought into contact with one or all of the surfaces of the film and adsorbed for an appropriate time. The method of contacting the oxidant only on one side with the above. In this case, the oxidizing agents are FeCl ₃ , CuCl ₂ ,
_{Fe (NO) 3, FeF 3} , Fe (CN) 3- 6, H 2 O 2, conventionally known oxidizing agents such as NaClO is preferably used.

(2) In the case of a polymer film having a hydroxyl group, determine the immersion time in a compound (monomer) having electron conductivity or the contact time with an oxidizing agent. Also by the above method, it is possible to obtain a polymer in which the compound is nonuniformly present and an electron conductive polymer compound is nonuniformly supported. Similarly, a suitable method is selected according to the purpose, such as a method in which a polymerization catalyst is allowed to uniformly exist in the film in advance and then the compound (monomer) having electron conductivity is brought into nonuniform contact.

(3) After dissolving a polymer having a hydroxyl group in a solvent, it is applied onto a conductive substrate such as a platinum wire or a platinum plate to scatter the solvent to form a film, and the conductive substrate Is used as an anode or a cathode, and is polymerized by electrolytic oxidation or electrolytic reduction in a solution containing a compound having electron conductivity, and the polymer compound having electron conductivity is unevenly present in the polymer film of the surface layer portion. Method (4) a method in which a polymer compound having electron conductivity is uniformly present in a polymer having a hydroxyl group, and then another polymer having a hydroxyl group in which the compound is not present is adhered and welded, Alternatively, on the polymer having a hydroxyl group in which the polymer compound having electron conductivity is uniformly present, another polymer having a hydroxyl group is dissolved in a solvent and cast to form a film, The cross section of the polymer In addition, any method in which a polymer compound having electron conductivity in the length direction or the width direction is present nonuniformly can be applied.

〔The invention's effect〕

As described above, the electroconductive polymer of the present invention can easily be obtained as a film having a thickness of 0.0001 to 1.0 cm, and the film has an asymmetric structure with respect to the membrane cross section like a reverse osmosis membrane. It may be a porous membrane. Of course, a film having a dense structure is also suitably used according to the purpose.

When the polymer having electric conductivity of the present invention is industrially used, the polymer having electron conductivity only on one surface is particularly effective. Further, when the polymer having conductivity of the present invention is used as a separation membrane, compared with a polymer film in which a compound having electron conductivity is not supported, ions,
Solvents and solvent permeability are completely different. Further, in the polymer having electric conductivity of the present invention, for example, when a polymer compound having electron conductivity is nonuniformly present in the film cross section, a potential is generated on both surfaces of the film. Then, this potential changes linearly with relative humidity. Incidentally, when the present invention is a fibrous substance, a polymer having a film-like substance in which the polymer having electron conductivity in the lengthwise direction is nonuniformly present, an electric potential is generated in the lengthwise direction, and this is also relative humidity. Has a linear correlation with. That is, the polymer having electric conductivity of the present invention can be used as a new moisture sensitive sensor element.

〔Example〕

Hereinafter, the content of the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

Example 1 A polyvinyl alcohol film membrane (thickness: 20 microns) was incorporated into an apparatus capable of reacting on only one side, and 5% was used for one side.
The pyrrole aqueous solution of was contacted with stirring and left for 24 hours. Then, after draining this liquid, wash with water and add 3%
When an aqueous solution of FeCl ₃ was added and stirred for 2 hours, the pyrrole impregnated in the polyvinyl alcohol thin film was oxidized and polymerized.

One side of the resulting film was electrically conductive and had a surface resistance of 800 Ω / cm and the other side of 2 MΩ / cm. Press the platinum plates on both sides of this film to make the internal resistance 100
When the voltage between both platinum electrodes was measured with a 0 MΩ digital voltmeter, it was 250 mV. At this time, the relative humidity is 55
%Met. When dry air was fed and the relative humidity was lowered to 35%, it became 160 mV.

The weight increase of the film due to the impregnation polymerization of the pyrrole was measured and found to be 82%.

Example 2 A reverse osmosis membrane made of cellulose diacetate having a salt rejection rate of 98% was used, and contact was made with a 5% aqueous solution of pyrrole for 24 hours in a device capable of reacting only one side on the side having a dense layer as in Example 1. Then, drain the liquid, wash with water, and then add 2% of CuCl ₂ .
The pyrrole impregnated with the aqueous solution was left standing for 2 hours to polymerize only the surface layer of the film.

When electrolysis of 0.5N saline was performed using the obtained treated membrane, the anion electrolysis efficiency was 95%, and the electrical resistance in 0.5N saline was 2.1 Ω-cm ² . On the other hand, 0.5% of reverse osmosis membrane (raw membrane) not impregnated with pyrrole and not polymerized
Similarly measured in normal saline, the anion transport number was 0.86 and the electrical resistance was 1.8 Ω-cm ² . The treated film obtained by impregnating and polymerizing pyrrole was black and opaque, and the reverse osmosis film (raw film) was a slightly devitrified black film. The weight increase due to impregnation polymerization of the film is 18%
Met.

Example 3 A polymer film having an ethylene unit and a vinyl alcohol unit, which was obtained by hydrolyzing a film made of a copolymer of vinyl acetate and ethylene, was used. That is, the film was immersed in a 5% acetonitrile solution of pyrrole for 48 hours at 30 ° C. to sufficiently impregnate the film with pyrrole, and then taken out, and then incorporated into a device capable of reacting only one side of the film membrane. A 0.1% aqueous solution of hydrogen peroxide was added to a 5% aqueous solution of FeCl ₃ alone, and one side of the film was contacted for 2 hours for polymerization. The film turned black.

When the obtained film was immersed in normal hydrochloric acid for doping, the electric resistance of the film surface on which the pyrrole was polymerized was 500 Ω / cm and the back surface was 2 MΩ / cm. Was 120%.

Example 4 A nonwoven fabric made of polyvinyl alcohol was cut into a strip shape with a width of 1 cm and a length of 5 cm. One end of this is soaked in a 5% aqueous solution of methymethylpyrrole, and when the liquid is sufficiently soaked to the end of the nonwoven fabric, the other end is soaked in a 5% FeCl ₅ aqueous solution to diffuse from the other end of the nonwoven fabric. -Methylpyrrole was polymerized in the nonwoven. When the polymerization reached the center of the strip-shaped nonwoven fabric, the cloth was removed, and the cloth was washed with methanol and then washed with water. When both ends of this non-woven fabric were sandwiched by copper plates and connected to a voltmeter with a high internal resistance as in Example 2 using these as terminals, a 320 mV activation was found. At this time, the relative humidity was 58%. Startup decreased linearly with decreasing relative humidity.

The weight increase was 210%.

Example 5 Polyvinyl alcohol was put into hot water to dissolve it, and a 5% aqueous solution was prepared. This was cast on a transparent conductive film provided with ITO to evaporate water to form a film, and further dried under reduced pressure to prepare a polyvinyl alcohol film having a thickness of 0.5 mm on the transparent conductive film. Then, the transparent conductive film-film prepared above was immersed in an electrolytic bath in which 0.3 mol of thiophene and 0.3 mol of (C ₄ H ₉ ) ₄ NBF ₄ were dissolved in a solution of acetonitrile and water (98: 2) to obtain a current density. It was electrolyzed at ² mA / cm ² for 10 minutes.

The above treated transparent conductive film was washed with water and dried, and then the electrode having the same transparent conductive film was pressed to the opposite side (film side) of the transparent conductive film. Relative humidity 58
When placed in an atmosphere of 23%, it is 23 between the electrodes on both sides of the film.
A 0 mV start-up occurred and when placed in dry air the start-up force was 0.

Claims (3)

[Claims] 1. A conductive polymer body in which a polymer compound having an electron conductivity is unevenly supported in a polymer body having a hydroxyl group. 2. The conductive polymer according to claim 1, which is a film-like material. 3. A method for producing a conductive polymer, wherein a monomer having electron conductivity is nonuniformly present in a polymer having a hydroxyl group, and the monomer is polymerized.