JPH03210326A - Conductive polymer and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a conductive polymer compound comprising a 3-n-higher alkylthiophene polymer and a method for producing the same.

[Conventional technology]

More than 100 types of conductive polymers obtained by electrolytic polymerization of pyrrole, thiophene, furan, aniline, etc. have been developed at present, and they are being developed as the basis of conductive polymers along with polyacetylenes.

Especially polypyrrole, polythiophene, polyaniline,
It is a material that can be easily obtained as an electrode coating film by electrolytic polymerization and exhibits superior thermal and chemical stability compared to polyacetylenes. Therefore, in addition to their original purpose as organic conductive materials, these materials are being applied in a wide range of fields, and are achieving unique developments different from polyacetylenes [Materials Technology, 6(1), 4
2 (1988)).

Application forms of these conductive polymer materials are classified into methods in which the materials are used as they are, methods in which the raw material monomers or produced polymers are chemically modified, and methods in which they are doped.

[Problem to be solved by the invention]

Although the physical properties of polymer materials such as pyrrole, thiophene, furan, and aniline obtained by electrolytic polymerization have been reported in detail, there are few examples of thiophene polymers being electrolytically polymerized. Methylthiophene polymers are known, but they have many problems due to poor film-forming properties.

Therefore, the present inventors investigated the production of thiophene polymers and found that 3-higher alkylthiophene polymers have excellent film-forming properties, can impart desired conductivity through self-doping, and have light absorption properties. It was discovered that

[Means to solve the problem]

The conductive polymer compound of the present invention has 3-higher alkylthiophene as a repeating unit and is doped with an anion.

Further, the conductive polymer compound of the present invention is produced by electrolytically polymerizing 3-n-higher alkylthiophene in an electrolytic solution containing a supporting electrolyte.

Further, the conductive polymer compound of the present invention is particularly produced by performing electrolytic polymerization at a low temperature.

The 3-n-higher alkylthiophene in the present invention has a higher alkyl group having 7 to 12 carbon atoms as a substituent, such as 3-n-nonylthiophene, 3-n-nonylthiophene,
-n-dodecylthiophene, 3-n-octylthiophene, etc. are preferably used. In particular, a polymer film formed from 3=n-octylthiophene is film-like and has excellent film formability.

Supporting electrolytes added to this electrolytic solution are not particularly limited, but include tetraalkylammonium tetrafluoroborate, tetraalkylammonium perchlorate, tetraalkylammonium chloride, tetraalkylammonium bromide, sodium formate,
ammonium formate, sodium fluoride, sodium bromide,
Potassium chloride, potassium sulfate, lithium chloride, zinc chloride, sodium perchlorate, magnesium perchlorate, sodium acetate, ammonium acetate, potassium acetate, lithium fluoride, potassium fluoride, cesium fluoride, silver fluoride, ammonium fluoride , potassium hydroxide, potassium alkoxide, sodium alkoxide, ammonium chloride, lithium perchlorate, lithium bromide, sodium nitrate, silver chloride, etc. may be used.

In addition, as the above-mentioned tetraalkylammonium compound,
Tetra-n-butylammonium compounds are preferred, and alkoxides derived from methanol and ethanol are preferred. The anions in the light-absorbing conductive polymer compound of the present invention are anions present in these supporting electrolytes.

The 3-n-higher alkylthiophene and the supporting electrolyte are dissolved or dispersed in a solvent or dispersion medium to form an electrolytic solution. Non-aqueous solvents are used as such solvents or dispersion media, such as acetonyl, propionitrile, acrylonitrile, isobutyronitrile,
Benzonitrile, phenylacetonitrile, formamide, N-N-dimethylformamide, N-methylformamide, N-N-dimethylacetamide, ~methylacetamide, N-methylpyrrolidone, hexamethylphosphoramide)', N, N, N' , N'-tetramethylurea, pyridine, dimethyl ether, 1,2-epoxybutane, tetrahydrofuran, 1,2-dimethoxyethane, 1,4-dioxane, dimethyl sulfoxide,
Examples include sulfolane, dimethylsulfone, propylene glycol cyclic sulfite, sulfur dioxide, nitromethane, nitrobenzene, dichloromethane, chloroform, propylene carbonate, acetone, acetic anhydride, tetrahexylammonium benzoate, and the like.

The electrolysis process is performed by constant current or constant voltage electrolysis by immersing the electrodes in a predetermined electrolytic solution and applying a voltage or current between the electrodes. At this time, the temperature of the electrolytic solution is preferably low, and the temperature range is preferably from +5°C to -5°C. As a result, the conductivity of the formed conductive polymer film can be further improved compared to when electrolysis is performed at room temperature.

Furthermore, the thickness of the resulting conductive polymer film can be controlled by the electrolytic conditions, and the electrolytic polymerization is carried out under an inert cloud atmosphere (
(nitrogen, argon, etc.), which can prevent the formation of by-products due to oxidation of reaction intermediates.

It is preferable to dissolve 1.0% to 15% by weight of 1.0% to 15% by weight in the solvent, and it is preferable to dissolve 6% to 30% by weight of the supporting electrolyte. The electrolysis conditions were around room temperature, and while blowing inert gas, 1 mA to 20 mA constant current electrolysis was performed.
A conductive compound is produced in minutes to 30 minutes.

One of the electrodes used for this electrolysis serves as a base material for the polymer deposited layer, on which the electrolytic polymer is deposited. Examples of such electrodes include transparent electrodes such as indium oxide-tin oxide films (ITO films), metal electrodes, and composite electrodes in which these are laminated on a base material such as plastics.

The conductive polymer formed on the electrode surface by electrolytic polymerization is
It can be post-processed using various materials. For example, plastics on the electrode side or conductive polymer membrane side.
It may be laminated as a film or sheet of paper, metal, ceramics, etc., or it may be coated with powder of resin, ceramics, etc.

The conductive polymer compound of the present invention has a light absorption property particularly in a long wavelength region, and the light that can be used include He-Ne laser, argon laser, He-C
Laser light such as d laser, dye laser, excimer laser, etc.
There are visible light, ultraviolet light, infrared light, etc. from lamps and light emitting diodes.

[Effect]

In the present invention, a 3-n-higher alkylthiophene polymer can be easily produced by electrolytic polymerization, and although the detailed reason is unknown, it has better film-forming properties than a 3-lower alkylthiophene polymer. It has been discovered that a polymer film with particularly excellent smoothness and thermal stability can be made.
It has also been found that it has light absorption properties and is useful, for example, as a recording layer in an optical information recording medium.

In addition, when producing a 3-n-higher alkylthiophene polymer, by carrying out the electrolytic polymerization conditions at a low temperature,
It has been found that the conductivity is improved compared to when the process is carried out at room temperature.

The present invention will be explained below using examples.

[Example 1] 6.0 g of tetra-n-butylammonium tetrafluorobole) was added to 100 mj of acetonitrile! An electrolytic solution was prepared by dissolving it in the solution.

A 2 cm x 4 cm ITO electrode was inserted into 60+ni electrolyte on the anode side to which 1.2 g of 3-n-nonylthiophene was added, and constant current electrolysis at +10 mA was performed for 10 minutes at room temperature while bubbling the electrolyte with N. ! did.

Through this electrolysis, 20 mg of a blue-green conductive polymer was deposited on the electrode surface. Moreover, the electrolyte solution changed color to green with the precipitation. FIG. 1 shows an infrared absorption spectrum of the deposited conductive polymer. This confirmed its structure. Further, when the optical absorption spectrum was measured, absorption was confirmed at 603 nm as shown in the 1g2 diagram.

Except that 1.0 g of 3-methylthiophene was used instead of 3-n-nonylthiophene in Example 1 above.
Electrolytic polymerization was carried out in the same manner as in Example 1.

Through this electrolysis, a dark brown conductive polymer is deposited on the electrode surface.
mg was precipitated. This film was inferior to that of the present invention in film formability, especially smoothness.

[Example 2] Dissolve 6.0 g of tetra-n-butylammonium tetrafluorobole in 100 mJ of acetonitrile to prepare an electrolyte! It's l1llL.

A 2 cm x 4c+a ITO electrode was inserted into 60 ml of electrolyte on the anode side to which 0.8 g of 3-n-dodecylthiophene was added, and +10 mA constant current electrolysis was continued for 10 minutes at room temperature while bubbling the electrolyte with N2. .

Through this electrolysis, 12 mg of a blue-green conductive polymer was deposited on the electrode surface. Further, as the electrolyte was deposited, the color changed to green.

The infrared absorption spectrum of the deposited conductive polymer film is shown in Figure 3.
As shown in the figure. This made the structure mm. In addition, when the optical absorption spectrum was measured, as shown in Figure 4, 64
Absorption was confirmed at 0 nm.

Further, the results of thermal analysis of this film are shown in FIG. Thermal analysis was performed using DSCIO manufactured by Seiko Electronics Co., Ltd. As can be seen from FIG. 5, three large endothermic peaks were observed in PoU (3-n-dodecylthiophene) of the present invention. Peak 1 seems to be a melting peak of a solvent or an unpolymerized product, since a yellow oil-like liquid comes out when compressed at room temperature.Although peak 2 is unknown, peak 3 is a melting peak of poly(
3-n-dodecylthiophene), and it can be seen that the conductive polymer compound of the present invention has thermal stability.

[Example 3] An electrolytic solution was prepared by dissolving 6.0 g of tetra-n-butylammonium tetrafluoroborate in 100 mβ of acetonitrile.

H using platinum plate and platinum wire as anode and cathode, respectively.
Of the electrolyte solution prepared above, 60 ml of the electrolyte solution prepared above was placed on the anode side, and the remaining 40 mJ was placed in an electrolytic polymerization apparatus using a type cell with the anode and cathode sides separated by a glass filter. was placed on the cathode side, 0.88 of 3-n-dodecylthiophene was added on the anode side, and electrolysis was performed at room temperature with a constant current of +10 mA for 30 minutes in a nitrogen atmosphere, resulting in a film thickness of 10 μm on the surface of the platinum electrode.
Thus, poly(3-n-dodecylthiophene) was obtained.

When the electrical conductivity of this polymer was measured using the 4-probe method, the specific volume conductivity was 2 S/Cm (Ω-1 cm-1
)Met.

Next, this electrolysis was carried out in an atmosphere at 0°C, and the specific volume conductivity of the obtained polymer was measured, and it was found to be 13 S/cm.
(Ω-1cm-1).

〔Effect of the invention〕

The conductive polymer of the present invention is a polymer film that has excellent conductivity, excellent film formability, particularly smoothness, and excellent thermal stability.

Furthermore, since the conductive polymer of the present invention has light absorption properties, it can be used in various fields such as electronic materials, organic semiconductor materials, and optical information recording media. Since it has particularly excellent light absorption in the long wavelength region, it is suitable as an 8-layer recording material for recording media for optical symbols, images, etc.

[Brief explanation of drawings]

11th! I is an infrared absorption spectrum diagram of the 3-n-nonylthiophene polymer of the present invention, FIG. 2 is a diagram showing the light absorption characteristics of the 3-n-nonylthiophene polymer, and FIG.
- Infrared absorption spectrum diagram of n-dodecylthiophene polymer, Figure 4 is a diagram showing the light absorption characteristics of 3-n-dodecylthiophene polymer, Figure 5 is thermal analysis of 3-n-dodecylthiophene polymer. It is a figure showing a result. Applicant: Dai Nippon Printing Co., Ltd.

Claims (3)

[Claims] (1) A conductive polymer compound having 3-n-higher alkylthiophene as a repeating unit and doped with an anion. (2) A method for producing a conductive polymer compound, which comprises electrolytically polymerizing 3-n-higher alkylthiophene in an electrolytic solution containing a supporting electrolyte. (3) The method for producing a conductive polymer compound according to claim 2, wherein the electrolytic polymerization is carried out at a low temperature.