Method for producing a conductive polymer solution

Abstract

To provide, e.g., a production method of a highly electroconductive polymer through an electrochemical oxidation polymerization method.SOLUTION: A production method for producing an electroconductive polymer solution comprises, e.g., a polymerization step of applying an electric potential difference to a solution containing a monomer of general formula (1), a solvent and an acid. [In the formula, M+ represents a hydrogen ion, an alkali metal ion, an ammonium ion, or the like.]SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing a conductive polymer solution and a conductive polymer.

Background Art

[0002] In recent years, semiconductor technology has developed rapidly, and a huge electronics-related industry and a highly informationized society have been constructed. Among them, as application examples of conductive polymers in electronic products, liquid crystal displays (LCDs), organic electroluminescence (organic EL), etc. are widely used in various fields such as televisions, computers, and various mobile devices that have become popular in recent years. Thus, the electronics-related industry using conductive polymers has achieved remarkable development.

[0003] As a material to support such an electronics-related industry, an externally doped conductive polymer in which a π-conjugated polymer represented by polyacetylene, polythiophene, polyaniline, polypyrrole, etc. is doped with an electron-accepting compound as a dopant has been developed. However, such an externally doped conductive polymer has problems such as being difficult to purify due to low solubility and being difficult to maintain stable doping.

[0004] Therefore, a so-called self-doped conductive polymer having a substituent (sulfonic group, sulfonate group, etc.) that combines water-solubility imparting and doping action in the polymer main chain directly or via a spacer has been developed. As self-doped conductive polymers, for example, sulfonated polyaniline, sulfonated polythiophene, etc. are known (see, for example, Non-Patent Documents 1 and 2). Among these, poly(4-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethoxy)-1-butanesulfonic acid) (PEDT-S) substituted with a linear alkylene sulfonic acid group has been reported (see, for example, Patent Document 1, Non-Patent Documents 3 and 4). In addition, the applicant of the present application has previously reported a self-doped conductive polymer having both high conductivity and excellent water-solubility (see, for example, Patent Document 2).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0006]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0007] In the above prior art (Patent Document 2), a self-doped conductive polymer is synthesized by a chemical oxidation polymerization method. However, in this method, metal ions derived from a catalyst or an oxidizing agent, particularly iron ions, tend to remain in the polymerization product as impurities. Such iron ion impurities can cause a decrease in the characteristics and durability of devices in applications such as organic EL and LCD. Therefore, for the conductive polymer obtained by the chemical oxidation polymerization method, a treatment for removing iron ions using a cation exchange resin has been proposed. However, the removal treatment using a cation exchange resin has problems such that it is preferable to reduce it in terms of an increase in the number of manufacturing steps, an increase in variable costs, an increase in environmental load, and the like.

[0008] On the other hand, an electrochemical oxidation polymerization method is known as a synthesis method that does not require a catalyst and an oxidizing agent and in which metal ions, particularly iron ions, hardly remain as impurities. However, it has been difficult to exhibit the high conductivity required for a solid electrolytic capacitor or the like for the self-doped conductive polymer obtained by the conventionally known electrochemical oxidation polymerization method. If the conductivity of the self-doped conductive polymer can be increased, it is possible to further improve the performance of a solid electrolytic capacitor or the like.

[0009] An aspect of the present invention aims to provide a method for producing a conductive polymer that realizes high conductivity by an electrochemical oxidation polymerization method, and the like.

Means for Solving the Problems

[0010] As a result of intensive studies to solve the above problems, the present inventors have found that by heat-treating a solution of a self-doped polythiophene obtained by an electrochemical oxidation polymerization reaction, an extremely high conductivity that could not be achieved with the self-doped conductive polymer obtained by the conventional electrochemical oxidation polymerization method is exhibited, and have thus completed the present invention.

[0011] That is, one aspect of the invention of the present application relates to a production method for obtaining a self-doped conductive polymer with higher electrical conductivity by heat-treating a polythiophene containing structural units represented by at least the following general formula (2) and the following general formula (3), which is obtained by an electrochemical oxidation polymerization method.

[0012] That is, one aspect of the invention of the present application includes the following [1] to [7].

[0013] [1] A production method for producing a conductive polymer solution containing a polythiophene containing at least two or more repeating structures selected from the group consisting of a repeating structure represented by the following general formula (2) and a repeating structure represented by the following general formula (3), (i) A polymerization step of bringing at least a pair of electrodes into contact with a solution containing a monomer containing at least a thiophene monomer represented by the following general formula (1), a solvent, and an acid, and applying a potential difference between the electrodes to obtain a polymer solid or a polymer solution that is a polymer of the monomer, (ii) When the polymer obtained in the polymerization step is the polymer solid, a dissolution step of mixing the polymer solid and the solvent to obtain the polymer solution, (iii) A heat treatment step of heating the polymer solution obtained in the polymerization step or the dissolution step, characterized by including.

[0014] [In the general formulas (1) and (2), M

[0015] [Chemical formula]

[0016] [Chemical formula]

[0017] [In the general formulas (1) and (2), M +Each independently represents a hydrogen ion, an alkali metal ion, an ammonium ion, a conjugate acid of an amine compound, or a quaternary ammonium cation. In the general formulas (1), (2), and (3), R 2 represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or a halogen atom. m represents an integer of 1 to 6, and n represents 0 or 1.] [2] The production method according to [1], wherein in the general formulas (1), (2), and (3), m is 2 or 3.

[0018] [3] In the general formulas (1), (2), and (3), the production method according to [1] or [2], wherein R 2 is a methyl group.

[0019] [4] The production method according to any one of [1] to [3], wherein in the polymerization step, the concentration of the monomer is 0.1 to 30% by weight.

[0020] [5] In the polymerization step, the production method according to any one of [1] to [4], wherein the current density is in the range of 0.01 to 10 mA / cm 2 .

[0021] [6] The production method according to any one of [1] to [5], wherein in the heat treatment step, the heating temperature is in the range of 50 to 250 °C.

[0022] [7] A conductive polymer containing a polythiophene containing at least two or more repeating structures selected from the group consisting of a repeating structure represented by the following general formula (2) and a repeating structure represented by the following general formula (3), wherein the carrier mobility is 1.5 to 10 cm 2 / Vs.

[0023]

Chemical formula

[0024]

Chem.

[0025] [In the general formula (2), M + each independently represents a hydrogen ion, an alkali metal ion, an ammonium ion, a conjugate acid of an amine compound, or a quaternary ammonium cation. In the general formulas (2) and (3), R 2 represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or a halogen atom. m represents an integer from 1 to 6, and n represents 0 or 1.]

Advantages of the Invention

[0026] According to one aspect of the present invention, a method for producing a conductive polymer with high conductivity by an electrochemical oxidation polymerization method can be provided, etc.

Modes for Carrying Out the Invention

[0027] Hereinafter, an embodiment of the present invention will be described in detail. Unless otherwise specified in this specification, "A to B" representing a numerical range means "A or more and B or less".

[0028] A method for producing a conductive polymer solution according to an embodiment of the present invention is a production method for producing a conductive polymer solution containing polythiophene containing at least two or more repeating structures selected from the group consisting of a repeating structure represented by the following general formula (2) and a repeating structure represented by the following general formula (3), (i) A polymerization step of obtaining a polymer solid or a polymer solution which is a polymer of the monomer by bringing at least one pair of electrodes into contact with a solution containing at least a monomer containing a thiophene monomer represented by the following general formula (1), a solvent, and an acid, and applying a potential difference between the electrodes, (ii) When the polymer obtained in the polymerization step is the polymer solid, a dissolution step of mixing the polymer solid and the solvent to obtain the polymer solution, (iii) a heat treatment step of heating the polymer solution obtained in the polymerization step or the dissolution step; A production method characterized by including the same.

[0029] [Chemical formula]

[0030] [Chemical formula]

[0031] [Chemical formula]

[0032] [In the general formulas (1) and (2), M + each independently represents a hydrogen ion, an alkali metal ion, an ammonium ion, a conjugate acid of an amine compound, or a quaternary ammonium cation. In the general formulas (1), (2), and (3), R 2 represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or a halogen atom. m represents an integer of 1 to 6, and n represents 0 or 1.] In the general formulas (1) and (2), M + each independently represents a hydrogen ion, an alkali metal ion, an ammonium ion (NH4 + ), a conjugate acid of an amine compound, or a quaternary ammonium cation.

[0033] The alkali metal ion is not particularly limited, and examples thereof preferably include Li ion, Na ion, or K ion.

[0034] The conjugate acid of the amine compound refers to a species in which a hydron (H + ) is added to the amine compound to form a cationic species, and any amine compound that reacts with a sulfonic acid group to form a conjugate acid may be used.

[0035] The amine compound in the conjugate acid of the above amine compound is not particularly limited. For example, an amine compound having an sp 1 hybrid orbital represented by the general formula N(R 3 )3, an amine compound having an sp 2 hybrid orbital such as pyridines or imidazoles, etc. may be mentioned.

[0036] The above-mentioned substituent R 1 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms with a substituent.

[0037] The above-mentioned alkyl group having 1 to 6 carbon atoms is not particularly limited. For example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a tert-pentyl group, a cyclopentyl group, an n-hexyl group, a 2-ethylbutyl group, or a cyclohexyl group, etc. may be mentioned.

[0038] The above-mentioned alkyl group having 1 to 6 carbon atoms with a substituent is not particularly limited. For example, an alkyl group having 1 to 6 carbon atoms having a group selected from the group consisting of a halogen atom, an alkyl group having 1 to 6 carbon atoms, an amino group, and a hydroxy group may be mentioned. Specifically, without being particularly limited, a trifluoromethyl group, a 2-hydroxyethyl group, etc. may be exemplified.

[0039] Among these, from the viewpoint of availability, as the substituent R 1 each independently, a hydrogen atom, a methyl group, an ethyl group, or a 2-hydroxyethyl group is preferable.

[0040] General formula N(R 1) The amine compound represented by 3 is not particularly limited. For example, ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, normal-propylamine, isopropylamine, normal butylamine, tertiary butylamine, hexylamine, aminoethanol, dimethylaminoethanol, methylaminoethanol, diethanolamine, N-methyldiethanolamine, triethanolamine, 3-amino-1,2-propanediol, 3-methylamino-1,2-propanediol, 3-dimethylamino-1,2-propanediol, or 1,4-butanediamine, etc. can be mentioned.

[0041] sp that forms the conjugate acid of the amine compound 2 The amine compound having an sp hybrid orbital that forms the conjugate acid of the amine compound is not particularly limited. For example, imidazole, N-methylimidazole, 1,2-dimethylimidazole, pyridine, picoline, or lutidine, etc. are exemplified.

[0042] Among these amine compounds that form the conjugate acid of the amine compound, from the viewpoint of availability, ammonia, ethanolamine compound, or imidazole compound is preferable.

[0043] The quaternary ammonium cation is not particularly limited. For example, tetramethylammonium cation, tetraethylammonium cation, tetranormalpropylammonium cation, tetranormalbutylammonium cation, or tetranormalhexylammonium cation, etc. can be mentioned. Among these, from the viewpoint of availability, preferably, tetramethylammonium cation and tetraethylammonium cation are used.

[0044] As described above, M +Each independently, it is preferably a hydrogen ion, Li ion, Na ion, K ion, ammonium ion, monoethanolammonium ion, diethanolammonium ion, triethanolammonium ion, imidazolium ion, N-methylimidazolium ion, or 1,2-dimethylimidazolium ion.

[0045] In the general formulas (1), (2), and (3) above, R 2 each independently represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, or a halogen atom.

[0046] The linear or branched alkyl group having 1 to 6 carbon atoms is not particularly limited, and examples thereof include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a neopentyl group, a tert-pentyl group, a cyclopentyl group, an n-hexyl group, a 2-ethylbutyl group, a cyclohexyl group, or an n-octyl group.

[0047] The halogen atom is not particularly limited, and examples thereof include a fluorine atom, a chlorine atom, and a bromine atom.

[0048] R 2 In terms of film-forming properties, each independently, it is preferably a hydrogen atom, a methyl group, an ethyl group, or a fluorine atom, more preferably a methyl group, an ethyl group, or a fluorine atom, and even more preferably a methyl group.

[0049] m each independently represents an integer of 1 to 6, preferably an integer of 1 to 4, and more preferably 2 or 3.

[0050] n each independently is 0 or 1, but preferably 1.

[0051] The structural unit represented by the general formula (3) represents the doped state of the structural unit represented by the general formula (2). In the conductive polymer according to one embodiment of the present invention, during electrolytic oxidation polymerization, a part of the structural unit represented by the general formula (2) undergoes a self-doping reaction and is converted to the structural unit represented by the general formula (3). This action causes the resulting polymer to exhibit electrical conductivity.

[0052] Dopants that cause an insulator-metal transition by doping can be divided into acceptors and donors. The former enters the vicinity of the polymer chain of a conductive polymer by doping and takes away π electrons from the conjugated system of the main chain. As a result, a positive charge (hole) is injected into the main chain, so it is also called a p-type dopant. Conversely, the latter donates electrons to the conjugated system of the main chain, and these electrons move through the conjugated system of the main chain, so it is also called an n-type dopant.

[0053] In one embodiment of the present invention, the dopant is a sulfo or sulfonate group covalently bonded within the polymer molecule, and is a p-type dopant. Such a polymer that exhibits electrical conductivity without the addition of an external dopant is called a self-doped polymer.

[0054] The thiophene monomer represented by the general formula (1) is not particularly limited. For example, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonate, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-ethyl-1-propanesulfonate, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-propyl-1-propanesulfonate, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-butyl-1-propanesulfonate, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-pentyl-1-propanesulfonate, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-hexyl-1-propanesulfonate, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-isopropyl-1-propanesulfonate, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-isobutyl-1-propanesulfonate, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-isopentyl-1-propanesulfonate, sodium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-fluoro-1-propanesulfonate, potassium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonate, 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonic acid, ammonium 3-[(2,3-dihydrothieno[3,4-b]-[1,4]dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonate, or 3-[(2,3-dihydrothieno[3,4-b]-[1,4) Triethylammonium [4-(thieno[3,4-b]-1,4-dioxin-2-yl)methoxy]-1-methyl-1-propanesulfonate and the like can be mentioned.

[0055] In addition, the thiophene monomer exemplified above can be produced, for example, as shown in the following general formula (4), using thieno[3,4-b]-1,4-dioxin-2-methanol that can be synthesized based on a known method (for example, Journal of Electroanalytical Chemistry, 443, 217-226 (1998)) and a branched sulfone compound.

[0056] [Chemical formula]

[0057] [In the general formula (4), R 2 has the same meaning as R represented by the general formula (1), and M 2 represents an alkali metal ion (such as Li ion, K ion, Na ion, or Cs ion).] 2 Furthermore, for the thiophene monomer represented by the general formula (4) thus produced, by acid treatment (contact with an acid or an H-ion type cation exchange resin, etc.), M 2 can be induced to a sulfonic acid in which M is a hydrogen atom (the thiophene monomer represented by the general formula (1) above). Furthermore, by contacting the sulfonic acid in which M is a hydrogen atom with an alkali metal compound, ammonia, an amine compound, or a quaternary ammonium compound, the thiophene monomer represented by the general formula (1) can be obtained. 2

[0058] In the method for producing a conductive polymer solution containing a conductive polymer according to an embodiment of the present invention, monomers other than the thiophene monomer represented by the general formula (1) can be used in combination. The monomers are not particularly limited, and examples thereof include thiophene, 3-hexylthiophene, 3,4-ethylenedioxythiophene, hydroxymethyl-3,4-ethylenedioxythiophene, hydroxy-3,4-propyleneoxythiophene, bromomethyl-3,4-ethylenedioxythiophene, N-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethyl)-2-aminoethanesulfonic acid, N-methyl-N-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethyl)-2-aminoethanesulfonic acid, 2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethanesulfonic acid, 6-(2,3-dihydrothieno[3,4-][1,4]dioxin-2-yl)-1-hexene, 6-(2,3-dihydrothieno[3,4-][1,4]dioxin-2-yl)-1-hexanesulfonic acid, 6-(2,3-dihydrothieno[3,4-][1,4]dioxin-2-yl)-1-butanesulfonic acid, or O-(2,3-dihydrothieno[3,4-b][1,4]dioxin-2-ylmethyl)-4-phenolsulfonic acid, and the like.

[0059] The method for producing a conductive polymer solution according to an embodiment of the present invention is characterized by including the steps of (i), (ii), and (iii) described above.

[0060] Hereinafter, the polymerization step of obtaining a polymer by polymerizing the monomer by bringing at least a pair of electrodes into contact with a solution containing at least (i) a monomer containing at least the thiophene monomer represented by the general formula (1), a solvent, and an acid, and applying a potential difference (applying a potential) between the electrodes will be described.

[0061] Regarding the polymerization step described above, at least a monomer containing the thiophene monomer represented by the general formula (1) is polymerized. The concentration range of the monomer in the polymerization reaction is not particularly limited, but it is preferably 0.1 to 30% by weight, more preferably 0.2 to 20% by weight, still more preferably 0.3 to 10% by weight, and even more preferably 0.5 to 8% by weight.

[0062] Here, the "concentration of the monomer" is a value represented by (weight of the monomer containing the thiophene monomer represented by the general formula (1)) / (weight of the monomer containing the thiophene monomer represented by the general formula (1) + weight of the solvent + weight of the acid) × 100 (weight%).

[0063] The solvent used in the polymerization step described above is not particularly limited, but it is preferably water, a solvent containing water, or a water-soluble solvent, and more preferably water, a water-water-soluble alcohol mixed solvent, or a water-soluble alcohol.

[0064] Examples of water include pure water, and distilled water or ion-exchanged water may also be used.

[0065] The water-soluble alcohol is not particularly limited, and examples thereof include alcohols such as methanol, ethanol, propanol, or butanol.

[0066] Among these solvents, water or methanol is preferred, and water is more preferred. Also, the solvent may be degassed or replaced with an inert gas such as nitrogen.

[0067] The acid used in the polymerization step is not particularly limited, and for example, an inorganic acid or an organic acid can be used. Here, examples of the inorganic acid include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, etc. Examples of the organic acid include methanesulfonic acid, p-toluenesulfonic acid, formic acid, acetic acid, lactic acid, benzoic acid, etc. Among these, sulfuric acid, methanesulfonic acid, or p-toluenesulfonic acid is preferable, and sulfuric acid is more preferable, in terms of excellent polymerization reaction rate.

[0068] Regarding a solution containing at least the monomer containing the thiophene monomer represented by the general formula (1), a solvent, and an acid, these components can be produced by mixing them in any order. Such a solution containing a monomer containing the thiophene monomer represented by the general formula (1), a solvent, and an acid before contacting with the electrode may sometimes be hereinafter referred to as a "charged solution".

[0069] The addition amount (content) of the acid is not particularly limited, but it is preferably that the normality of the acid in the charged solution (= molar concentration of the acid × valence of the acid) is 0.01 to 10 [N], more preferably 0.01 to 5 [N], and even more preferably 0.01 to 2 [N]. When the charged solution is an aqueous solution, it is preferable to add (contain) the acid so that the liquidity (pH) of the charged solution is in the range of 0 to 6.5, more preferably in the range of 0 to 5, and even more preferably in the range of 0 to 3.

[0070] The method of bringing at least a pair of electrodes into contact with the above solution is not particularly limited. For example, the above solution is placed in the above container, and the anode and cathode are immersed in the above solution to apply a potential difference. A three-electrode method using a reference electrode may be used, or a two-electrode method may be used. Also, it can be carried out by a method in which the above container itself is used as an electrode and the counter electrode is brought into contact with the above solution.

[0071] The potential difference applied between the electrodes is a potential difference capable of electrochemically oxidatively polymerizing the thiophene monomer represented by the general formula (1), and although not particularly limited, the potential of the anode defined by the three-electrode method is preferably in the range of 0 to +5 V, more preferably in the range of +0.5 to +2.5 V with respect to the reference electrode.

[0072] Also, the current density during polymerization is not particularly limited, but is preferably in the range of 0.01 to 10 mA / cm 2 and more preferably in the range of 0.1 to 6 mA / cm 2 of the range.

[0073] The material of the container only needs to have sufficient durability against the solution, and although not particularly limited, for example, glass, a glass-lined container, Teflon (registered trademark), polyethylene, polypropylene, polyvinyl chloride, stainless steel, etc. are preferable.

[0074] The shape of the container only needs to be able to hold the solution inside, and may have a structure in which the anode and the cathode can be separated by a porous partition or an ion bridge.

[0075] As the electrode used in the polymerization step, an electrode capable of causing an electrochemical oxidation reaction to proceed on its surface by applying a potential difference between the electrodes can be used. Such electrodes are not particularly limited, and examples include gold, platinum, nickel, titanium, stainless steel, glassy carbon, ITO, etc., and these may be used alone or in combination of two or more.

[0076] The reaction pressure of the polymerization step may be any of normal pressure, reduced pressure, and increased pressure.

[0077] The reaction atmosphere in the method for producing a conductive polymer solution according to an embodiment of the present invention is not particularly limited, and may be an air atmosphere or an inert gas atmosphere such as nitrogen or argon. More preferably, it is an inert gas atmosphere.

[0078] The reaction temperature of the polymerization step is, for example, a temperature at which the thiophene monomer represented by the general formula (1) can be electrochemically oxidatively polymerized, and is not particularly limited, but a range of -10 to 50 °C is preferable, and a range of 0 to 40 °C is more preferable.

[0079] The reaction time of the polymerization step is not particularly limited, but for example, it can be a time during which the oxidative polymerization of the thiophene monomer represented by the general formula (1) sufficiently proceeds, and is not particularly limited, but a range of 0.5 to 200 hours is preferable, and a range of 0.5 to 80 hours is more preferable.

[0080] The polymerization step can also be carried out in a state containing a surfactant in addition to the thiophene monomer, solvent, and acid represented by the general formula (1). The addition of the surfactant is preferable in terms of improving the solubility and dispersibility of the thiophene monomer used as a raw material and the thiophene polymer produced in the solvent.

[0081] The surfactant is not particularly limited, and for example, anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, etc. can be used, but more preferably, it is at least one selected from the group consisting of anionic surfactants and nonionic surfactants.

[0082] Examples of the anionic surfactant include, but are not particularly limited to, carboxylic acid type, sulfonic acid type, sulfuric acid ester type, phosphoric acid ester type, etc.

[0083] Examples of the carboxylic acid type include, but are not particularly limited to, sodium octanoate, sodium decanoate, sodium palmitate, sodium stearate, etc.

[0084] The sulfonic acid type mentioned above is not particularly limited, and examples thereof include sodium hexanesulfonate, sodium decanesulfonate, sodium toluenesulfonate, sodium octylbenzenesulfonate, sodium dodecylbenzenesulfonate, sodium naphthalenesulfonate, and the like.

[0085] The sulfate ester type mentioned above is not particularly limited, and examples thereof include sodium lauryl sulfate, sodium laureth sulfate, ammonium lauryl sulfate, and the like.

[0086] The phosphate ester type mentioned above is not particularly limited, and examples thereof include sodium lauryl phosphate, potassium lauryl phosphate, and the like.

[0087] The nonionic surfactant is not particularly limited, and examples thereof include polyethylene glycol type surfactants, acetylene glycol type surfactants, polyhydric alcohol type surfactants, polymer type nonionic surfactants, and the like.

[0088] The polyethylene glycol type surfactant mentioned above is not particularly limited, and examples thereof include higher alcohol ethylene oxide adducts, alkylphenol ethylene oxide adducts, fatty acid ethylene oxide adducts, polyhydric alcohol fatty acid ester ethylene oxide adducts, higher alkylamine ethylene oxide adducts, ethylene oxide adducts of oils and fats, or polypropylene glycol ethylene oxide adducts, and the like.

[0089] The acetylene glycol type surfactant mentioned above is not particularly limited, and examples thereof include 2,4,7,9 - tetramethyl - 5 - decyne - 4,7 - diol, Surfynol (registered trademark, manufactured by Air Products), Olfine (registered trademark, manufactured by Nitto Chemical Industry Co., Ltd.), and the like.

[0090] The polyhydric alcohol type surfactant is not particularly limited, and examples thereof include fatty acid esters of glycerol, fatty acid esters of pentaerythritol, fatty acid esters of sorbitol and sorbitan, fatty acid esters of sucrose, alkyl ethers of higher alcohols, fatty acid amides of alkanolamines, and the like.

[0091] The polymeric nonionic surfactant is not particularly limited, and examples thereof include polyvinylpyrrolidone and copolymers of polyvinylpyrrolidone. The copolymer of polyvinylpyrrolidone is not particularly limited, but those having both a hydrophilic part and a hydrophobic part in the polymer chain are preferred. Examples thereof include a copolymer obtained by grafting polyvinylpyrrolidone onto polyvinyl alcohol, a [vinylpyrrolidone-vinyl acetate] block copolymer, a [vinylpyrrolidone-methyl methacrylate] copolymer, a [vinylpyrrolidone-normal butyl methacrylate] copolymer, a [vinylpyrrolidone-acrylamide] copolymer, and the like.

[0092] By performing the polymerization reaction as described above, a polymer of monomers including the thiophene monomer represented by the general formula (1) can be produced. The polymer can be obtained as a polymer solution or a polymer solid. When the polymer is obtained as a polymer solid, all or part of the solid tends to be obtained as a deposit on the anode.

[0093] When the polymer is obtained as a polymer solid, a dissolution step represented by the following (ii) is carried out to obtain a polymer solution.

[0094] Next, the dissolution step of mixing the polymer solid and a solvent to obtain a polymer solution, which is carried out when the polymer obtained in the polymerization step (ii) of one embodiment of the present invention is a polymer solid, will be described.

[0095] When the polymer solid obtained in the above polymerization step is deposited on the electrode, it is preferable that the polymer solid be separated from the electrode in advance. The method of such separation is not particularly limited, and examples thereof include peeling by impact, peeling by ultrasonic waves, peeling using a spatula or the like, and dissolution peeling using a good solvent. In addition, regardless of whether or not it was deposited on the electrode, it is preferable to perform a filtration treatment on the obtained polymer solid. The filtration treatment method is not particularly limited, and examples thereof include suction filtration, pressure filtration, centrifugal filtration, and natural filtration.

[0096] The filter used for filtering the polymer solid may be any filter that can separate the polymer solid from the solvent or the like after the polymerization step, and is not particularly limited. Examples thereof include filter paper, a membrane filter, a glass filter, and filter cloth.

[0097] Next, the polymer solid separated above is mixed with a solvent to obtain a polymer solution.

[0098] The solvent is not particularly limited, but is preferably water, a solvent containing water, or a water-soluble solvent, and more preferably water, a water-water-soluble alcohol mixed solvent, or a water-soluble alcohol.

[0099] Examples of water include pure water, and distilled water or ion-exchanged water may also be used.

[0100] The water-soluble alcohol is not particularly limited, and examples thereof include alcohols such as methanol, ethanol, propanol, and butanol.

[0101] Among these solvents, water, a water-methanol mixed solvent, or methanol is preferable, and water is more preferable. In addition, the solvent may be degassed or replaced with an inert gas such as nitrogen.

[0102] Regarding the polymer solution, its viscosity is preferably in the range of 0.1 to 1000 mPa·s.

[0103] Also, regarding the polymer concentration in the polymer solution, although not particularly limited, it is preferably in the range of 0.01 to 20% by weight. Regarding this polymer concentration, in terms of excellent processing efficiency in the heat treatment step of (iii) below, it is preferably 0.1 to 10% by weight, and more preferably 0.2 to 5% by weight.

[0104] Next, the heat treatment step of heating the polymer solution obtained in (iii) the polymerization step or the dissolution step of one embodiment of the present invention will be described.

[0105] Regarding the polymer solution to be heated in the heat treatment step, the polymer solution produced in the polymerization step of (i) or the dissolution step of (ii) can be used as it is, or the polymer solution produced in the polymerization step of (i) or the dissolution step of (ii) can be purified by a generally known purification method and then used.

[0106] The purification method is not particularly limited, and examples include ultrafiltration, dialysis, ion exchange resin treatment, etc. These purifications may be performed alone or in combination of two or more.

[0107] The ion exchange resin is not particularly limited, and examples include weakly acidic cation exchange resin, strongly acidic cation exchange resin, weakly basic anion exchange resin, strongly basic anion exchange resin, etc. These resins may be used alone or two or more of them may be used.

[0108] The heating temperature in the heat treatment step is preferably higher than the polymerization reaction temperature of polythiophene in order to obtain high conductivity. Although not particularly limited, it is preferably 50 to 200°C, more preferably 60 to 180°C, and even more preferably 70 to 150°C.

[0109] Regarding the heating in the above heat treatment step, it is preferably heated to a temperature of the maximum reaching temperature (°C) in the polymerization step + 10°C or higher, more preferably heated to a temperature of the maximum reaching temperature (°C) in the polymerization step + 20°C or higher, and still more preferably heated to a temperature of the maximum reaching temperature (°C) in the polymerization step + 50°C or higher.

[0110] The heating in the above heat treatment step may be carried out in a closed system or an open system. When heating at a high temperature, since evaporation of the solvent etc. is conceivable, it is preferably carried out in a closed system, and a pressure-resistant container may be used as necessary.

[0111] The time of the above heating is not particularly limited, but it is preferably 0.1 hour or more and 1000 hours or less. More preferably, it is 0.5 hour or more and 100 hours or less, and still more preferably 1 hour or more and 50 hours or less.

[0112] By performing the above steps (i), (ii), and (iii), the target conductive polymer solution can be produced.

[0113] Regarding the method for producing a conductive polymer according to an embodiment of the present invention, in addition to the above steps (i), (ii), and (iii), further, (iv) an anion exchange step (so-called purification step) in which the polymer solution obtained in the heat treatment step is brought into contact with an anion exchange resin to ion-exchange anions in the polymer solution with hydroxide ions may be included. Regarding the anion exchange step of (iv), it is preferably between the polymerization step of (i) and the heat treatment step of (iii), between the dissolution step of (ii) and the heat treatment step of (iii), or after the heat treatment step of (iii), and it may be carried out once or in combination a plurality of times.

[0114] The anion exchange resin mentioned above is not particularly limited, and examples thereof include weakly basic anion exchange resins, strongly basic anion exchange resins, etc. However, weakly basic anion exchange resins are preferred in terms of the excellent point that the purity of the conductive polymer can be efficiently increased. Further, the weakly basic anion exchange resin mentioned above is not particularly limited, but amine-type weakly basic anion exchange resins are preferred. As the amine-type weakly basic anion exchange resin, commercially available products can be used and are not particularly limited. For example, Diaion (registered trademark) WA20, Diaion (registered trademark) WA21, Diaion (registered trademark) WA30 (manufactured by Mitsubishi Chemical Corporation), Amberlite (registered trademark) IRA67, Amberlite (registered trademark) IRA96SB, Amberlite (registered trademark) IRA98 (manufactured by Organo Corporation), Dowex (registered trademark) 66 (manufactured by Dow Chemical Company), Duolite (registered trademark) A368MS (manufactured by Rohm & Haas Company), Lewatit (registered trademark) MP62WS, Lewatit (registered trademark) Monoplus MP64, etc. can be preferably used.

[0115] Regarding the conductive polymer solution produced through the above-mentioned respective steps, it can be adjusted to a conductive polymer solution suitable for the intended use by further performing operations such as viscosity adjustment or component adjustment.

[0116] The method for the above-mentioned viscosity adjustment is not particularly limited, and examples thereof include a method of removing the solvent by ultrafiltration or distillation, a method of adding a solvent, and homogenization treatment (using an ultrasonic homogenizer, a high-pressure homogenizer, etc.). When adding a solvent, the solvent is not particularly limited, but examples thereof include the same solvent as that used in the polymerization step, and water is more preferred.

[0117] Regarding the above-mentioned component adjustment, it is not particularly limited, and operations such as adding conventionally known additives generally used in the field of conductive polymer compositions based on conventionally known methods can be shown.

[0118] Regarding the conductive polymer solution produced by the above manufacturing method, it is characterized by containing a polythiophene containing at least two or more repeating structures selected from the group consisting of the repeating structure represented by the general formula (2) and the repeating structure represented by the general formula (3), and further characterized by having a low iron ion content. Since the iron ion content is low, for the manufacturing method according to an embodiment of the present invention, the purification operation by the cation exchange process, which was commonly performed in the prior art, is not essential, and the effects of reducing the number of steps and the environmental load can be achieved.

[0119] Note that for the conductive polymer solution, it is desired that the iron ion content is low in the application scenario, and preferably its iron content is 10 ppm or less, preferably 5 ppm or less, more preferably 2 ppm or less, more preferably 0.5 ppm or less, and even more preferably 0.2 ppm or less.

[0120] Regarding the conductive polymer produced by the above manufacturing method, it preferably has a high carrier mobility. Although not particularly limited, its carrier mobility is preferably 1.5 to 10 cm 2 / Vs, and more preferably 1.8 to 5 cm 2 / Vs.

[0121] Also, according to an embodiment of the present invention, a highly efficient manufacturing method by reducing the manufacturing process enables the production of a conductive polymer solution with excellent conductivity. This leads to the realization of a highly efficient manufacturing method for electronic products with excellent energy efficiency and can contribute to the achievement of sustainable development goals (SDGs), such as Goal 7, "Ensure access to affordable, reliable, sustainable and modern energy for all."

[0122] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

Examples

[0123] Next, one embodiment of the present invention will be described in detail by way of examples, but the present invention should not be construed as being limited thereto.

[0124] (Electric conductivity measurement method) A vinyl tape was attached so as to divide a slide glass (26×70 mm) into two equal parts in the longitudinal direction. A conductive polymer solution (concentration of the conductive polymer: about 1.0% by weight) was dropped onto one part (26×35 mm) partitioned by the vinyl tape and dried at 60°C for 30 minutes and then at 120°C for 10 minutes. Thereafter, a conductive polymer cast film with a film thickness d = about 5 μm was produced by heat treatment at 200°C under vacuum for 1 hour. The produced conductive polymer cast film was cut into 10×10 mm pieces. The film thickness d was measured using a stylus profilometer D-100 (KLA-Tencor) in dry air (dried for 10 minutes at a humidity of 10% or less).

[0125] The evaluation of conductivity was performed using the electric conductivity as an index. First, a four-probe probe PSP (Mitsubishi Chemical Corporation) connected to a resistivity meter Loresta GP (Mitsubishi Chemical Corporation) was fixed with a crank, and the cast film was lifted using a lab jack and pressed directly against the probe to measure the resistance R. The resistivity correction coefficient (RCF value), which is a correction value determined by the film shape (film thickness, size, measurement coordinates), was integrated with the resistance R measured by the four-probe method, and the electric conductivity σ was calculated from the following formula.

[0126] [Number]

[0127] Here, σ is the electric conductivity (S / cm), I is the current (A), U is the voltage (V), RCF is the resistivity correction coefficient, and d is the film thickness of the film (μm).

[0128] (Molecular weight measurement method) The weight-average molecular weight (Mw), number-average molecular weight (Mn), and polydispersity index (PDI) were measured by GPC (gel permeation chromatography). For the high-performance liquid chromatography apparatus (Prominence, Shimadzu Corporation), columns TSKgel α-M and guardcolumn α (Tosoh) were used. As the standard sample, poly(4-styrenesulfonic acid) (PSS, American polymer standard) was used. As the eluent, dimethyl sulfoxide (DMSO) in which 10 mM tetrabutylammonium bromide (TBABr) and 10 mM N-diisopropylamine (DIPA) were dissolved was used. The measurement sample was neutralized and diluted to a conductive polymer concentration of 5×10 -3 wt% using the eluent, and then ultrasonicated at 50°C for 20 minutes, reacted at 50°C for 18 hours, and then ultrasonicated for 20 minutes to perform dedoping treatment.

[0129] (Measurement of reflection spectrum and calculation of carrier mobility) Using an ultraviolet-visible spectrophotometer (V-670, manufactured by JASCO Corporation), the prepared conductive polymer cast film was used as the measurement sample, and the reflection spectrum was measured in the wavelength range of 300 to 2500 nm. The intersection of the extrapolated line of the reflection spectrum and 0% reflectance was defined as the plasma frequency f p , and the carrier density N p was calculated from the following formula starting from the plasma frequency f c .

[0130]

Number

[0131] Here, f p : Plasma frequency (ω p / 2π) (Hz), N c : Carrier density ( / cm 3 ), e: Elementary charge of electricity (1.6×10 -19 C), ε0: Dielectric constant (8.85×10 -12 F / m), m * : Effective mass (0.82m0), m0: Free electron mass (9.11×10 -31 kg).

[0132] Furthermore, from the electrical conductivity σ and carrier density N obtained as described above, the carrier mobility μ was calculated by using the following equation. c Here, the electrical conductivity σ (S / cm), carrier density N

[0133] [Equation]

[0134] where the electrical conductivity σ (S / cm), carrier density N c ( / cm 3 ), elementary charge e (1.6×10 -19 C).

[0135] (Viscosity measurement) The viscosity of the conductive polymer solution (conductive polymer concentration of about 1.0 wt%) was measured at 25 °C using a torsional vibration viscometer (Viscomade VM-10A-L, Sekonic).

[0136] (pH measurement) The pH of the conductive polymer solution (conductive polymer concentration of about 1.0 wt%) was measured at 25 °C using a pH meter (F-53, Horiba, Ltd.).

[0137] (Particle size measurement) The particle size of the conductive polymer was evaluated using a dynamic light scattering measurement device (Nanotrac UPA-UT151, Nikkiso Co., Ltd.). After measuring about 2 ml of pure water as the background, the conductive polymer solution (conductive polymer concentration of about 1.0 wt%) was diluted 100 - 200 times by adding 10 - 20 μl and then measured. The median diameter (D 50 ) at which the particle size distribution and the integrated particle size distribution curve intersect the horizontal axis at 50% was calculated using the software Microtrac II DMS.

[0138] Example 1 (Method of electrochemical oxidative polymerization) Platinum (35 cm 2 ) was used as the working electrode, and titanium (690 cm 2) The polymerization was carried out using a three - electrode system with a silver - silver chloride reference electrode. First, 10 g of sodium 3 - [(2,3 - dihydrothieno[3,4 - b]-[1,4]dioxin - 2 - yl)methoxy]-1 - methyl - 1 - propanesulfonate (a thiophene monomer represented by the following general formula (5), produced according to a conventional method) was dissolved in 990 g of 1M dilute sulfuric acid solution. The concentration of the thiophene monomer at this time was 1.0% by weight. The mixed solution in which the thiophene monomer was completely dissolved was added to a reaction vessel. The temperature of the mixed solution in the reaction vessel was adjusted to 0 °C, and after nitrogen flow for 2 hours, a potential of +0.8 V with respect to the reference electrode was applied to the working electrode at a current density of 1 mA / cm 2 As a result, a solid substance was deposited after applying the potential for 20 hours. As a result of analyzing the precipitate, it was polythiophene (a polymer composed of repeating structures represented by the following general formula (6) and the following general formula (7)) in which the above - mentioned thiophene monomer was polymerized.

[0139]

Chemical formula

[0140]

Chemical formula

[0141]

Chemical formula

[0142] (Purification of Electrochemical Oxidation Polymer) The polythiophene deposited by electrochemical oxidative polymerization (a polymer composed of the repeating structures represented by the general formula (6) and the general formula (7)) was recovered by filtration through a glass filter. Next, 3 kg of pure water was added to the obtained polythiophene, stirred overnight, and then homogenized for 10 minutes using an ultrasonic homogenizer to obtain a polymer solution. The above polymer solution was purified by ultrafiltration (cut-off molecular weight = 10 kD), and then undissolved solids were removed by suction filtration. Further, the polymer solution obtained by suction filtration was concentrated by ultrafiltration (cut-off molecular weight = 10 kD) to obtain a deep blue aqueous solution (conductive polymer solution) containing 1.0% by weight of polythiophene (a polymer composed of the repeating structures represented by the general formula (6) and the general formula (7), which is a conductive polymer).

[0143] (Heat treatment of the conductive polymer solution) The aqueous solution containing the polythiophene (a polymer composed of the repeating structures represented by the general formula (6) and the general formula (7)) adjusted to a concentration of 1.0% by weight by the above ultrafiltration was heat-treated at 100 °C for 24 hours with stirring to obtain a conductive polymer solution.

[0144] (Electrical conductivity) When the electrical conductivity of the conductive polymer contained in the conductive polymer solution obtained by the production method according to an embodiment of the present invention was measured by the above electrical conductivity measurement method, it was 322 S / cm.

[0145] (Molecular weight) When the molecular weight of the conductive polymer contained in the conductive polymer solution obtained by the production method according to an embodiment of the present invention was measured by the above molecular weight measurement method, the weight average molecular weight was 15,706 g / mol.

[0146] (Carrier density, carrier mobility) When the carrier density and carrier mobility of the conductive polymer contained in the conductive polymer solution obtained by the production method according to an embodiment of the present invention were measured by the above reflection spectrum method, the carrier density was 1.23×1021 / cm 3 The carrier mobility was 1.81 cm 2 / Vs.

[0147] (Viscosity) When the viscosity of the conductive polymer solution obtained by the production method according to one embodiment of the present invention was measured by the above viscosity measurement method, it was 2.68 mPa·s.

[0148] (pH) When the pH of the conductive polymer solution obtained by the production method according to one embodiment of the present invention was measured by the above pH measurement method, it was 1.87.

[0149] (Particle size) When the viscosity of the conductive polymer solution obtained by the production method according to one embodiment of the present invention was measured by the above particle size measurement method, it was 2.07 nm.

[0150] The results are shown in Table 1, Table 2 and Table 3.

[0151] Example 2 In Example 1, except that the condition of a current density of 1 mA / cm 2 was changed to a current density of 2 mA / cm 2 , the same polymerization method operations, purification operations, and heat treatment of the polymerization solution as in Example 1 were performed to obtain a deep blue aqueous solution (conductive polymer solution) containing 1.0% by weight of polythiophene (a polymer composed of the repeating structures represented by the general formula (6) and the general formula (7), which is a conductive polymer). The results of the physical property evaluation are shown in Table 1, Table 2 and Table 3.

[0152] Example 3 In Example 1, except that the condition of a current density of 1 mA / cm 2 was changed to a current density of 3 mA / cm 2Except for changing to, the operations of the polymerization method, purification operations, and heat treatment of the polymerization solution were the same as those in Example 1, and a concentrated group blue aqueous solution (conductive polymer solution) containing polythiophene (a polymer composed of the repeating structures represented by the general formula (6) and the general formula (7) and being a conductive polymer) with a concentration of 1.0% by weight was obtained. The results of the physical property evaluation are shown in Tables 1, 2, and 3.

[0153] Example 4 In Example 1, the condition of a current density of 1 mA / cm 2 was changed to a current density of 4 mA / cm 2 Except for this change, the operations of the polymerization method, purification operations, and heat treatment of the polymerization solution were the same as those in Example 1, and a concentrated group blue aqueous solution (conductive polymer solution) containing polythiophene (a polymer composed of the repeating structures represented by the general formula (6) and the general formula (7) and being a conductive polymer) with a concentration of 1.0% by weight was obtained. The results of the physical property evaluation are shown in Tables 1, 2, and 3.

[0154] Example 5 In Example 1, the condition of a current density of 1 mA / cm 2 was changed to a current density of 5 mA / cm 2 Except for this change, the operations of the polymerization method, purification operations, and heat treatment of the polymerization solution were the same as those in Example 1, and a concentrated group blue aqueous solution (conductive polymer solution) containing polythiophene (a polymer composed of the repeating structures represented by the general formula (6) and the general formula (7) and being a conductive polymer) with a concentration of 1.0% by weight was obtained. The results of the physical property evaluation are shown in Tables 1, 2, and 3.

[0155] Example 6 In Example 1, the condition of a current density of 1 mA / cm 2 was changed to a current density of 6 mA / cm 2 Except for this change, the operations of the polymerization method, purification operations, and heat treatment of the polymerization solution were the same as those in Example 1, and a concentrated group blue aqueous solution (conductive polymer solution) containing polythiophene (a polymer composed of the repeating structures represented by the general formula (6) and the general formula (7) and being a conductive polymer) with a concentration of 1.0% by weight was obtained. The results of the physical property evaluation are shown in Tables 1, 2, and 3.

[0156] Reference Example 1 In Reference Example 1, the same polymerization method operations and purification operations as in Example 1 were performed except that heat treatment was not performed, and a deep group blue aqueous solution containing 1.0% by weight of polythiophene (a polymer composed of the repeating structures represented by the general formula (6) and the general formula (7)) was obtained. The results of the physical property evaluation are shown in Tables 1, 2, and 3.

[0157] Reference Example 2 In Reference Example 2, the same polymerization method operations and purification operations as in Example 2 were performed except that heat treatment was not performed, and a deep group blue aqueous solution containing 1.0% by weight of polythiophene (a polymer composed of the repeating structures represented by the general formula (6) and the general formula (7)) was obtained. The results of the physical property evaluation are shown in Tables 1, 2, and 3.

[0158] Reference Example 3 In Reference Example 3, the same polymerization method operations and purification operations as in Example 3 were performed except that heat treatment was not performed, and a deep group blue aqueous solution containing 1.0% by weight of polythiophene (a polymer composed of the repeating structures represented by the general formula (6) and the general formula (7)) was obtained. The results of the physical property evaluation are shown in Tables 1, 2, and 3.

[0159] Reference Example 4 In Reference Example 4, the same polymerization method operations and purification operations as in Example 4 were performed except that heat treatment was not performed, and a deep group blue aqueous solution containing 1.0% by weight of polythiophene (a polymer composed of the repeating structures represented by the general formula (6) and the general formula (7)) was obtained. The results of the physical property evaluation are shown in Tables 1, 2, and 3.

[0160] Reference Example 5 In Reference Example 5, the same polymerization method operations and purification operations as in Example 5 were performed except that heat treatment was not performed, and a deep group blue aqueous solution containing 1.0% by weight of polythiophene (a polymer composed of the repeating structures represented by the general formula (6) and the general formula (7)) was obtained. The results of the physical property evaluation are shown in Tables 1, 2, and 3.

[0161] Reference Example 6 In Example 6, the same polymerization method operations and purification operations as in Example 6 were performed except that heat treatment was not carried out, and a deep blue aqueous solution containing polythiophene (a polymer composed of the repeating structures represented by the general formula (6) and the general formula (7)) at a concentration of 1.0% by weight was obtained. The results of physical property evaluation are shown in Tables 1, 2, and 3.

[0162] [Table 1]

[0163] [Table 2]

[0164] [Table 3]

[0165] As can be seen from Table 1 above, by heat-treating the conductive polymer solution containing polythiophene, the electrical conductivity of the coating film could be improved. Also, as can be seen from Table 2 above, by heat-treating the conductive polymer solution containing polythiophene, the carrier mobility of the coating film could also be improved.

[0166] Also, as can be seen from each of the above tables, the conductive polymer and its solution produced by the manufacturing method according to an embodiment of the present invention showed the characteristic that, although the molecular weight, electrical conductivity, and carrier mobility were improved compared to those without heat treatment, the viscosity was decreased. For conductive polymers, generally, as the molecular weight and electrical conductivity increase, the viscosity tends to increase, which tends to have an adverse effect on impregnation into capacitor micropores, coatability, and operability, etc. However, according to the manufacturing method according to an embodiment of the present invention, it is possible to provide a conductive polymer and its solution having an unprecedentedly high electrical conductivity and yet having high operability.

[0167] Thus, according to one embodiment of the present invention, it is possible to produce and provide a self-doped conductive polymer exhibiting high electrical conductivity, which has been difficult to achieve with conventionally known electrochemical oxidative polymerization, and a solution thereof.

[0168] In addition, with respect to the conductive polymer produced by the production method according to one embodiment of the present invention, it exhibits a remarkable and heterogeneous effect of showing an unprecedentedly high carrier mobility. Therefore, the conductive polymer is extremely useful industrially in that it can improve the performance of organic ELs, LCDs, capacitors, and the like.

Industrial Applicability

[0169] Since the conductive polymer obtained by the method for producing a conductive polymer solution according to one embodiment of the present invention has high electrical conductivity, it can be used as an antistatic agent, a solid electrolyte of a capacitor, and a separator for an antistatic film and a wound aluminum electrolytic capacitor. In addition, applications to electrochromic elements, transparent electrodes, transparent conductive films, thermoelectric conversion materials, chemical sensors, actuators, electromagnetic wave shielding materials, etc. can also be expected.

Claims

1. A manufacturing method for producing a conductive polymer solution containing polythiophene containing at least two or more repeating structures selected from the group consisting of a repeating structure represented by the following general formula (2) and a repeating structure represented by the following general formula (3), (i) A polymerization step of obtaining a polymer solid or a polymer solution that is a polymer of the monomer by bringing at least a pair of electrodes into contact with a solution containing at least a monomer containing a thiophene monomer represented by the following general formula (1), a solvent, and an acid, and applying a potential difference between the electrodes; (ii) A dissolution step of obtaining the polymer solution by mixing the polymer solid and the solvent when the polymer obtained in the polymerization step is the polymer solid; (iii) A heat treatment step of heating the polymer solution obtained in the polymerization step or the dissolution step; The manufacturing method is characterized by including the above steps. 【Chemical 1】 【Chemical 2】 [Chemical Formula 3] In the general formulas (1) and (2), M ＋ each independently represents a hydrogen ion, an alkali metal ion, an ammonium ion, a conjugate acid of an amine compound, or a quaternary ammonium cation. In the general formulas (1), (2), and (3), R ２ represents a linear or branched alkyl group having 1 to 6 carbon atoms. m represents an integer of 1 to 6, and n represents 0 or 1.]

2. The manufacturing method according to Claim 1, wherein in the general formulas (1), (2), and (3), m is 2 or 3.

3. In the general formulas (1), (2) and (3), the R ２ is a methyl group, and the production method according to claim 1 or claim 2.

4. The manufacturing method according to any one of Claims 1 to 3, wherein in the polymerization step, the concentration of the monomer is 0.1 to 30% by weight.

5. In the polymerization step, the current density is in the range of 0.01 to 10 mA / cm ２ The manufacturing method according to any one of claims 1 to 4, which is in the range of.

6. The manufacturing method according to any one of Claims 1 to 5, wherein in the heat treatment step, the heating temperature is in the range of 50 to 250°C.

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