JPH0138805B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a novel conductive polymer composition and a method for producing the same. More specifically, the present invention covers various electronic components, electrodes, sensors,
The present invention relates to a conductive polymer composition mainly composed of a novel thiophene-based polymer, which is useful for photoelectric conversion elements, and a method for easily producing this composition by electrolytic polymerization.

Background of the Invention In recent years, with the remarkable technological development in the electrical and electronic industries, there has been a demand for new materials with excellent electrical functions, and materials with various electrical properties have been discovered in the field of polymer chemistry. Although many materials have already been put into practical use, the search for materials with even better electrical properties is actively underway. In particular, organic conductive materials with electrical conductivity are
For example, it can be widely used as a material for various electronic components, electrodes, sensors, photoelectric conversion elements, etc., and research is actively being conducted to develop organic conductive materials with excellent properties.

So far, known organic conductive materials include polyacetylene, poly(p-phenylene), polyphenylene sulfide, polypyrrole, etc. to which a doping agent is added, and organic metal polymers. However, these organic conductive materials are not necessarily satisfactory in terms of conductivity, moldability, economic efficiency, etc.

On the other hand, as a thiophene-based polymer composition, a polymer composition obtained by electropolymerizing thiophene [Journal of Chemical Society Chemical Communications (JCSChem.
Commun.), page 382 (1983),” and a polymer composition obtained by electrolytically polymerizing 3-methylthiophene (“Synth.Met.”).
Volume 6, page 317 (1983)] is known.

However, although these polymer compositions can have good electrical conductivity by selecting an appropriate supporting electrolyte, they are extremely difficult to mold because they are insoluble and infusible in various solvents. , has little practical value as a conductive polymer composition.

Problems to be Solved by the Invention Under these circumstances, the purpose of the present invention is to provide a material that has excellent electrical conductivity, good moldability, and can be manufactured economically. An object of the present invention is to provide a novel conductive polymer composition with high commercial value.

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted extensive research on the electrolytic polymerization of thiophenes, and have found that thiophenes have a linear alkyl group having 6 to 12 carbon atoms at the 3-position. A new conductive polymer composition can be easily obtained by electrolytically polymerizing the thiophenes using a dopant-containing polymer as a supporting electrolyte, which has excellent electrical conductivity. The inventors have discovered that the material has a high practical value because it has a high degree of strength, is soluble in various solvents, and can be easily molded. Based on this knowledge, the present invention has been completed.

That is, the present invention provides the general formula (In the formula, n is an integer of 5 to 11, and m is an integer of 80 to 350.) Dopant is added in an amount of 0.01 to 0.5 mol% based on the monomer units, based on the monomer units represented by The present invention provides conductive polymer compositions doped with the general formula (In the formula, n has the same meaning as above.) It can be produced by electrolytically polymerizing a thiophene derivative represented by the following formula.

In the present invention, the monomers used for electropolymerization are:
As shown in the general formula (), it is a thiophene derivative having a straight chain alkyl group having 6 to 12 carbon atoms at the 3-position, and specific examples of the alkyl group include n-
hexyl group, n-heptyl group, n-octyl group,
Examples include n-nonyl group, n-decyl group, n-undecyl group and n-dodecyl group. If the alkyl group has less than 6 carbon atoms, the resulting polymer will be poorly soluble or insoluble in the solvent;
If it is larger than 12, the mechanical properties of the polymer will be poor and the degree of polymerization will also be low, making it undesirable.

The supporting electrolyte in the present invention can provide a dopant, and examples of the dopant include hexafluorophosphate ion, hexafluoroarsenate ion, tetrafluoroborate ion,
Examples include anions such as perchlorate ion, trifluoromethanesulfonate ion, various halogen ions, and sulfate ion; among these, hexafluorophosphate ion, hexafluoroarsenate ion, tetrafluoroborate ion, and perchlorate ion. Acid ions and trifluoromethanesulfonate ions are
This is suitable because it can impart a sufficiently high electrical conductivity (60 to 110 S/cm) to the resulting polymer for practical use. As the supporting electrolyte, a salt containing the anion is used.

In the present invention, the electrodes used for electrolytic polymerization include noble metals such as gold and platinum, nickel,
Examples include those made of carbon, or glass electrodes with indium oxide, tin oxide, etc. deposited on the glass surface. In addition to these, aluminum or mercury may also be used as the cathode.

The electrolytic polymerization is carried out in an electrolytic solution prepared by dissolving the supporting electrolyte in a solvent such as nitrobenzene, benzonitrile, or propylene carbonate to a concentration of 0.01 to 0.2 mol/ml, preferably using an inorganic substance such as nitrogen or argon. It is carried out in an active atmosphere according to methods such as constant current electrolysis, constant potential electrolysis, and constant voltage electrolysis. The current application time is appropriately selected so that the polymer film formed on the anode has a desired thickness.

In this way, the obtained polymer composition has the general formula (in the formula, n is an integer of 5 to 11, m is an integer of 80 to 350), and the dopant is 0.01 to 0.5 mol% based on the monomer units. It is doped in the range of . If the amount of the dopant is less than 0.01 mol% based on the monomer unit, the electrical conductivity is low and practical conductivity cannot be obtained, and if the amount exceeds 0.5 mol% based on the monomer unit, the electrical conductivity is too low considering the amount. The electrical conductivity does not increase, but rather the mechanical properties deteriorate, which is not preferable. This polymer composition is soluble in solvents such as toluene and tetrahydronaphthalene.

The polymer composition of the present invention is a novel composition that has not been published in any literature, and the anionic dopant is eliminated by electrolytic reduction, resulting in a polymer composed of monomer units represented by the above general formula (). becomes. This material is soluble in solvents such as methylene chloride, chloroform, benzene, toluene, and tetrahydronaphthalene, and is easily molded, so it can be used as a new polymeric material. Moreover, the polymer is
In the infrared absorption spectrum, absorption was observed in the wavelength region of 820 cm- ¹ , confirming that it had a 2,3,5-trisubstituted thiophene ring.

The polymer in the polymer composition of the present invention is
Those having a degree of polymerization in the range of 80 to 350 and a molecular weight in the range of 10,000 to 50,000 are preferable in terms of mechanical properties and moldability. The degree of polymerization can be determined using a vapor pressure molecular weight measuring device.

Effects of the Invention The conductive polymer composition of the present invention has excellent electrical conductivity, good moldability, and can be manufactured economically, so it has high practical value, such as various electronic components. It can be used for electrodes, sensors, photoelectric conversion elements, etc.

EXAMPLES Next, the present invention will be explained in more detail with reference to Examples.

Example 1 A solution was prepared by dissolving 0.673 g (4 mmol) of 3-n-hexylthiophene in 20 ml of nitrobenzene, and adding 0.138 g (0.5 mmol) of tetraethylammonium hexafluorophosphate as a supporting electrolyte.

Next, the above solution was placed in an electrolytic cell using an ITO glass electrode as an anode and a platinum plate as a cathode, and after argon gas was blown in for 15 minutes, electrolytic polymerization was performed at 5°C. When polymerized for 10 minutes at a current density of 2 mA/cm ² , a black film-like polymer composition was obtained on the anode in which hexafluorophosphate ions were doped in an amount of 0.27 mol % based on the monomer units.

This film-like polymer composition has a thickness of 7.0 μm,
It showed an electrical conductivity of 95S/cm. It was also dissolved in toluene and tetrahydronaphthalene at a rate of about 60% (W/W).

Reference Example When 3-n-hexylthiophene was electrolytically polymerized for 10 minutes at a current density of 2 mA/cm ² in the same manner as in Example 1, a black film-like polymer composition with hexafluorophosphate ions doped on the anode was obtained. I got something.

Next, reverse the polarity of the electrode and use a current density of 0.5 mA/
Electrolytic reduction was performed by flowing a current until the voltage difference between the two electrodes exceeded 5 V in cm ² and reached a constant voltage, and hexafluorophosphate ions were removed from the composition. Next, this material was washed with methanol, dried, and
A red film-like polymer was obtained.

This polymer consists of methylene chloride, chloroform,
90% (W/
W) More dissolved. Further, the degree of polymerization determined by a vapor pressure molecular weight measuring device using chloroform was 230.

Example 2 In Example 1, 20 ml of propylene carbonate was used instead of nitrobenzene, and the current density was 10 mA/
When 3-n-hexylthiophene was electrolytically polymerized in the same manner as in Example 1, except that the electrolytic polymerization was carried out at cm ² for 4 minutes, hexafluorophosphate ion was 0.22 mol based on the monomer unit based on the polymer. % doped black filmy polymer composition was obtained.

This polymer composition has a thickness of 8.0 μm,
It showed an electrical conductivity of 110S/cm.

Example 3 In Example 1, 0.786 g of 3-n-octylthiophene was used instead of 3-n-hexylthiophene.
Electrolytic polymerization was carried out in exactly the same manner as in Example 1, except that 4 mmol of hexafluorophosphate ion was doped into the polymer based on the monomer unit. A polymer composition was obtained.

This polymer composition has a thickness of 6.0 μm, and
It showed an electrical conductivity of 78S/cm. It was also dissolved in toluene and tetrahydronaphthalene at a rate of about 70% (W/W).

Example 4 In Example 3, 20 ml of propylene carbonate was used instead of nitrobenzene, and the current density was 10 mA/
When 3-octylthiophene was electrolytically polymerized in the same manner as in Example 3, except that the electropolymerization was carried out at cm ² for 4 minutes, hexafluorophosphate ions doped the polymer at 0.20 mol% based on the monomer unit. A black film-like polymer composition was obtained.

This film-like polymer composition has a thickness of 6.8 μm,
It also showed an electrical conductivity of 52S/cm.

Example 5 In Example 1, 1.008 g of 3-n-dodecylthiophene was used instead of 3-n-hexylthiophene.
Electrolytic polymerization was carried out in the same manner as in Example 1, except that the polymer was electrolytically polymerized using (4 mmol) and at a current density of 2 mA/cm ² for 5 minutes. A black filmy polymer composition doped with 0.24 mol % based on mer units was obtained.

This film-like polymer has a thickness of 6.9 μm and
It showed an electrical conductivity of 67S/cm. Also, toluene has about
60 (W/W), approximately 90% tetrahydronaphthalene
(W/W) Dissolved.

Example 6 In Example 5, 3-n-dodecylthiophene was prepared in exactly the same manner as in Example 5, except that 0.109 g (0.5 mmol) of tetraethylammonium tetrafluoroborate was used instead of tetraethylammonium hexafluorophosphate. As a result of electrolytic polymerization, a black film-like polymer composition was obtained in which the polymer was doped with 0.30 mol% of tetrafluoroborate ions based on the monomer units.

This film-like polymer composition has a thickness of 6.5 μm,
It also showed an electrical conductivity of 61S/cm.

Claims (1)

[Claims] 1. General formula (In the formula, n is an integer of 5 to 11, and m is an integer of 80 to 350.) Dopant is added in an amount of 0.01 to 0.5 mol% based on the monomer units, based on the monomer units represented by A conductive polymer composition doped with 2 The dopant is hexafluorophosphate ion,
The composition according to claim 1, wherein the anion is selected from hexafluoroarsenate ion, tetrafluoroborate ion, perchlorate ion and trifluoromethanesulfonate ion. 3 In a medium containing a supporting electrolyte capable of donating a dopant, the general formula (In the formula, n is an integer of 5 to 11.) A general formula characterized by electrolytically polymerizing a thiophene derivative represented by (In the formula, n is an integer of 5 to 11, and m is an integer of 80 to 350.) Dopant is added in an amount of 0.01 to 0.5 mol % based on the monomer units to a polymer consisting of monomer units represented by 1. A method for producing a conductive polymer composition comprising doping. 4 The dopant is hexafluorophosphate ion,
4. The manufacturing method according to claim 3, wherein the anion is selected from hexafluoroarsenate ion, tetrafluoroborate ion, perchlorate ion, and trifluoromethanesulfonate ion.