KR101656991B1 - Production of conductive polymer solution by viscosity control and cured product thereby - Google Patents

Abstract

The present invention relates to a manufacturing method of a conductive polymer solution, and to a cured film manufactured through the same. According to the present invention, the conductive polymer solution uses an ionic polymer electrolyte having 70-78% of a degree of sulfonation, thereby reducing viscosity by 20% or more in comparison to the existing viscosity. Thus, the conductive polymer solution has an improved degree of deaeration, and can be coated through various equipment such as a slot die coater and the like, without an additive or dilution.

Description

TECHNICAL FIELD The present invention relates to a method for producing a conductive polymer solution and a cured coating film using the same,

The present invention relates to a process for producing a conductive polymer solution through viscosity control and a cured coating film produced thereby.

BACKGROUND OF THE INVENTION [0002] As various home appliances and communication devices including computers are digitized and rapidly improved in performance, development of transparent conductive materials for use as electrodes of electronic devices is required. For example, in order to realize a portable display, the electrode material for a display must have transparency and low resistance as well as high flexibility to cope with mechanical impact, and even if the device is overheated and exposed to a high temperature, Should not be large.

ITO (indium-tin oxide) is the most commonly used transparent electrode material for displays. However, when the transparent electrode is formed of ITO, not only is an excessive cost consumed, but also it is difficult to realize a large area. In particular, when the ITO is coated on a large area, the change of the sheet resistance is large, and the luminance and luminous efficiency of the display are reduced. In addition, indium, which is the main raw material of ITO, is a limited minerals and is rapidly depleting as the display market expands.

 In order to overcome the disadvantages of ITO, studies are being conducted to form a transparent electrode using a conductive polymer having excellent flexibility and a simple coating process.

In order to form the transparent electrode, it is preferable to use a conductive polymer having high conductivity. As a method of synthesizing the conductive polymer having high conductivity, a conductive polymer monomer is mixed with an ionic polymer electrolyte having a high sulfonation degree to cause polymerization of the conductive polymer monomer. At this time, the ionic polyelectrolyte used in the past has a degree of polysulfonation of at least 80%. However, when an ionic polymer electrolyte having a degree of polysulfonation of 90% or more is used, hydrogen bonds due to a large number of -SO ₃ H functional groups occur and the viscosity of the solution becomes high, which makes mixing and degassing difficult. And the conversion rate is low, so that the process time is increased and the cost is increased. Also, since the viscosity of the prepared conductive polymer solution is high, various coating equipment can not be used.

Korean Patent Publication No. 2012-0077112

The present invention provides a process for preparing a conductive polymer solution through viscosity control and a cured coating film prepared by the process, wherein the conductive polymer solution contains a conductive polymer and an ionic polymer electrolyte, The degree of oxidation may be from 70 to 78%, and the deaeration may be from 97 to 99.98%.

The present invention can provide a method for producing a conductive polymer solution. As an example,

A conductive polymer and an ionic polymer electrolyte,

The sulfonation degree of the ionic polymer electrolyte is 70 to 78%

And the step of de-airing comprises the step of initiating the reaction solution at 97 to 99.98%.

In addition, the present invention can provide a cured coating film prepared by the method for producing a conductive polymer solution.

The conductive polymer solution according to the present invention improves the deaerating performance by lowering the viscosity by 20% or more by using an ionic polymer electrolyte having a sulfonation degree of 70 to 78%. As a result, And the like. Thus, it is possible to save the processing time and cost, and through this, the produced cured coating film can realize high electrical conductivity and transparency.

The present invention relates to a process for producing a conductive polymer solution and a cured coating film prepared thereby.

As one example of the method for producing the conductive polymer solution,

A conductive polymer and an ionic polymer electrolyte,

The sulfonation degree of the ionic polymer electrolyte is 70 to 78%

And the step of de-airing comprises the step of initiating the reaction solution at 97 to 99.98%.

Specifically, when a cured coating film of a conductive polymer solution containing a conductive polymer and an ionic polymer electrolyte is used as a conductive polymer film, an ionic polymer electrolyte having a high degree of sulfonation of 80% or more in order to realize high electrical conductivity and transparency Were used. However, when using an ionic polymer electrolyte having such a high sulfonation degree as described above, hydrogen bonds are generated due to a large number of sulfonic groups (-SO ₃ H), resulting in an increase in viscosity and difficulty in effective mixing and degassing. Time increases and cost increases. Especially, in the case of polystyrene, it was confirmed that the viscosity of the aqueous solution increased rapidly from 80% of the degree of sulfonation.

However, the conductive polymer solution according to the present invention has a high solubility in an aqueous solution and an ionic polymer electrolyte having a sulfonation degree of 70 to 78%, which has a sulfone group sufficient to be used for doping, And when it is cured and used as a conductive polymer film, high electrical conductivity and transparency can be realized.

At this time, the degree of sulfonation of the ionic polymer electrolyte was calculated through the ratio of carbon and sulfur using elemental analysis (EA). Specifically, the prepared ionic polymer electrolyte was dried in a vacuum drying oven at 50 캜 for 48 hours under vacuum, and then measured in powder form.

In the present invention, the conductive polymer reaction solution before initiation may exhibit high deaeration. For example, deaerating may range from 97 to 99.98% or 97.5 to 99.98%. In addition, the ionic polymer electrolyte having a high solubilization degree has a problem that it is difficult to degas due to a high viscosity. However, in the present invention, by using an ionic polymer electrolyte having a degree of sulfonation of 70 to 78% The existing problems can be solved. Concretely, it is possible to prevent peroxidation of the conductive polymer through excellent deaeration in the above-mentioned range, to improve the conductivity, to accelerate the polymerization rate and to shorten the processing time.

The deaeration is a value calculated based on the amount of oxygen dissolved in the solvent during the synthesis based on the amount of oxygen in the air. The higher the deaeration degree, the more oxygen is removed and the higher the conductivity, It can mean that a coating film can be produced.

The viscosity of the conductive polymer solution prepared by the above method may be 1 to 100 cp when the conductive polymer is contained at a concentration of 1 wt%. For example, the viscosity may range from 1 to 50 cp or from 8 to 100 cp. This can be achieved by controlling the degree of sulfonation of the ionic polymer electrolyte in the range of 70 to 78%. Within the range of viscosity within the above range, the conductive polymer solution can be easily mixed with the conductive polymer monomer and the ionic polymer electrolyte, thereby increasing the conversion ratio to the conductive polymer through bonding between the monomers within a short period of time, . Specifically, it can be used without limitation in various coating methods such as spray coating, slot die coating and the like by controlling the viscosity of the conductive polymer solution to be as low as the above range.

The viscosity of the conductive polymer solution may satisfy the following general formula (1).

[Formula 1]

(S2 - S1) / S2 x 100? 20%

In the general formula 1,

S1 is the viscosity of a conductive polymer solution prepared using an ionic polymer electrolyte having a degree of sulfonation of 70 to 78%

S2 is the viscosity of a conductive polymer solution prepared using an ionic polymer electrolyte having a sulfonation degree of 80% or more.

Specifically, the conductive polymer solution according to the present invention improves the deaeration by lowering the viscosity by 20% or more by using an ionic polymer electrolyte having a sulfonation degree of 70 to 78% Slot die coater, and the like. Thus, it is possible to save process time and cost, and through this, the produced cured coating film can realize high electrical conductivity and transparency.

The molecular weight of the ionic polymer electrolyte may be from 20,000 to 1,000,000. For example, the molecular weight may be from 70,000 to 400,000 or from 200,000 to 1,000,000. By using an ionic polymer electrolyte having a molecular weight within the above range, bonding between the conductive polymer monomers can be promoted, and when the prepared conductive polymer solution is cured and used as a conductive polymer film, high electrical conductivity can be realized. In addition, the conductivity can be easily controlled according to the molecular weight of the ionic polymer electrolyte.

The ionic polymer electrolyte may include a monomeric anion or a polyanion.

Examples of such monomeric anions include, but are not limited to, C ₁ -C ₂₀ -alkanesulfonic acid, aliphatic perfluorosulfonic acid, aliphatic C ₁ -C ₂₀ -carboxylic acid, aliphatic perfluorocarboxylic acid, C ₁ -C ₂₀ -alkyl groups Such as aromatic sulfonic acid, cycloalkanesulfonic acid, iron sulfate, sodium persulfate, tetrafluoroborate, hexafluorophosphate, perchlorates, hexafluoroantimonate, hexafluoroarsenate, And may include hexafluoroarsenates or hexachloroantimonates.

Examples of such polyanions include anions of polymeric carboxylic acids (e.g., polyacrylic acid, polymethacrylic acid or polymaleic acid), polymeric sulfonic acids (e.g., polystyrene sulfonic acid and polyvinyl sulfonic acid) and poly Sulfonic-co-maleic acid). Specifically, the ionic polymer electrolyte may be polystyrene sulfonic acid having a molecular weight of 20,000 to 1,000,000.

The conductive polymer may be an optionally substituted polypyrrole, polyaniline or polythiophene.

For example, the conductive polymer may include a structure represented by the following formula (1).

[Chemical Formula 1]

In Formula 1,

X and Y each independently represent O, S, Si or N,

R ₁ and R ₂ each independently represent hydrogen, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 3 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms,

n is an integer from 2 to 2000,

Alternatively, R ₁ and R ₂ are bonded to each other to represent a fused ring structure.

At this time, the alkyl group may mean a functional group derived from a linear or branched saturated hydrocarbon.

Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a 1,1-dimethylpropyl group, , 2-dimethylpropyl group, 2,2-dimethylpropyl group, 1-ethylpropyl group, 2-ethylpropyl group, n-hexyl group, Methylpropyl group, 1-methylbutyl group, 2-methylbutyl group, 1,1-dimethylbutyl group, 1,2-dimethylbutyl group, 2,2- Dimethylbutyl group, 1,3-dimethylbutyl group, 2,3-dimethylbutyl group, 2-ethylbutyl group, 2-methylpentyl group and 3-methylpentyl group.

In addition, the aryl group may mean a monovalent substituent derived from an aromatic hydrocarbon.

Specific examples of the aryl group include a phenyl group, a naphthyl group, an anthracenyl group, a phenanthryl group, a naphthacenyl group, a pyrenyl group, A tolyl group, a biphenylyl group, a terphenyl group, a chrycenyl group, a spirobifluorenyl group, a fluoranthenyl group, a fluorene group, A perfluoroalkyl group, a fluorenyl group, a perylenyl group, an indenyl group, an azulenyl group, a heptalenyl group, a phenalenyl group, a phenanthrenyl group, group).

Further, the heteroaryl group represents an aromatic heterocycle or a heterocyclic group derived from a monocyclic or condensed ring. The heteroaryl group may include at least one of nitrogen (N), sulfur (S), oxygen (O), phosphorus (P), selenium (Se), and silicon (Si) as a heteroatom.

Specific examples of the heteroaryl group include pyrrolyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazolyl, tetrazolyl, benzotriazolyl, pyrazolyl, imidazolyl, An imidazolyl group, an imidazolyl group, a thiazolyl group, an isothiazolyl group, a benzothiazolyl group, a benzothiadiazolyl group, a phenothiazyl group, an isoxazolyl group, a furazanyl group, a phenoxazinyl group, , A benzooxazolyl group, an oxadiazolyl group, a pyrazoloxazolyl group, an imidazothiazolyl group, a thienopuranyl group, a furopyrrolyl group, and a pyridoxazinyl group.

As an example, the conductive polymer may be represented by the following formula (1): K (K is an arbitrary integer between 2 and 2000) repeating structure, X, Y, R ₁ and R ₂ may be different from each other. For example, the conductive polymer represented by the structure of the formula (1) may be selected from the structures of the following formulas (2) to (4).

(2)

(3)

[Chemical Formula 4]

In the above Chemical Formulas 2 to 4,

and n is an integer of 2 to 2000.

Specifically, the conductive polymer may be at least one selected from the group consisting of poly (3,4-ethylenedioxythiophene): polystyrene sulfonic acid, polypyrrole: polystyrene sulfonic acid, and polythiophene: polystyrene sulfonic acid.

The solution containing the conductive polymer and the ionic polymer electrolyte may further contain a dopant.

For example, the dopant may include at least one of an ammonium salt electrolyte, a sodium salt electrolyte, a lithium salt electrolyte, an iron salt electrolyte, a sulfonic acid compound, and sulfuric acid. For example, the dopant is not particularly limited, but may include organic compounds containing oxygen and nitrogen.

The ammonium salt electrolyte may include at least one of tetra-n-Bu ₄ NClO ₄ , n-Bu ₄ NPF ₆ , n-Bu ₄ NBF ₄ and n-Et ₄ NClO ₄ .

The sodium salt electrolyte may include, for example, at least one of NaPF ₆ , NaBF _4, and NaClO ₄ .

The lithium salt electrolyte, for _{example, LiClO 4, LiPF 6, LiBF} 4, LiN (SO 2 CF 3) 2, LiN (SO 2 C 2 F 5) 2, LiCF 3 SO 3, LiC (SO 2 CF 3 _{) 3, LiPF 4 (CF 3} ) 2, LiPF 3 (C 2 F 5) 3, LiPF 3 (CF 3) 3, LiPF 3 (iso-C 3 F 7) 3, LiPF 5 (iso-C 3 F 7 ) And a lithium salt electrolyte having a cyclic alkylene group.

For example, the lithium salt having a cyclic alkylene group may include (CF ₂ ) ₂ (SO ₂ ) ₂ NLi and (CF ₂ ) ₃ (SO ₂ ) ₂ NLi.

The iron salt electrolyte may include, for example, iron (III) oxide p-toluenesulfonic acid.

The sulfonic acid compound is, for example, an alkanesulfonic acid having 1 to 20 carbon atoms, a perfluoroalkanesulfonic acid having 1 to 20 carbon atoms, an alkylhexylcarboxylic acid having 1 to 20 carbon atoms, a purple having 1 to 20 carbon atoms An aromatic sulfonic acid substituted or unsubstituted by an alkyl group having 1 to 20 carbon atoms, and a cycloalkanesulfonic acid (e.g., camphorsulfonic acid).

Specifically, the sulfonic acid compound may be selected from the group consisting of methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid, dodecanesulfonic acid, octadecanesulfonic acid, nonadecanesulfonic acid, trifluoromethanesulfonic acid, perfluorobutane Sulfonic acid, perfluorooctanesulfonic acid, ethylhexylcarboxylic acid, benzenesulfonic acid, o -toluenesulfonic acid, p -toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, P-toluenesulfonic acid and p-toluenesulfonic acid.

The dopant may be discontinued or a mixture of two or more dopants may be used.

For example, the dopant may be either a sulfuric acid or a sulfonic acid compound, or two or more thereof.

The dopant may be dissolved and mixed in a solvent.

The solvent used in mixing the dopant is not particularly limited as long as it can dissolve the dopant and can be mixed with water. For example, the solvent may include at least one of water, tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), acetonitrile, and an alcohol-based solvent.

The method of preparing the conductive polymer solution is not particularly limited, and can be produced through a conventional production process.

The present invention can provide a cured coating film of the conductive polymer solution.

Specifically, the cured coating film may be prepared by preparing a conductive polymer solution, followed by post-treatment such as filtration and washing, applying the prepared conductive polymer solution on a specific substrate, and then curing the conductive polymer solution to prepare a conductive polymer film .

The electric conductivity of the cured coating film may be 600 S / cm or more. For example, the electrical conductivity may range from 600 to 1500 S / cm or from 600 to 1000 S / cm. The electrical conductivity within the above range of the cured coating film using the conductive polymer solution according to the present invention may mean a low surface resistance. It is confirmed that high performance can be realized when applied to electronic devices.

Hereinafter, the present invention will be described in more detail with reference to the following Examples. However, the scope of the present invention is not limited by the following Examples.

Example  One

12.53 g of polystyrene sulfonic acid (PSS, Mw 75,000) having a degree of sulfonation of 70% in a reaction vessel was dissolved in 1400 g of distilled water and stirred with an impeller for 1 hour under nitrogen gas injection. Then, 0.2 g of iron sulfate was added and stirred until it was dissolved. When all of the iron sulfate was dissolved, the temperature of the solution was lowered to 13 ° C, and 30 g of an aqueous solution containing 11.9 g of sodium persulfate was added. After that, deaeration was measured. Denitrification was calculated using the oxygen concentration at the point where the oxygen concentration no longer changes using a dissolved oxygen analyzer. Thereafter, 5.014 g of 3,4-ethylenedioxythiophene (EDOT) monomer was added and polymerization reaction was carried out for 35 hours. Then, a mixture of a cation exchange resin and an anion exchange resin mixed at a ratio of 1: 1 500 ml of ion exchange resin was added to remove unnecessary ions to prepare a conductive polymer solution. Thereafter, homogenization treatment was carried out.

Then, the prepared conductive polymer solution (concentration of 1 wt%) and DMSO were mixed at a weight ratio of 95: 5, coated on a glass substrate using a spin coater, and dried at 150 ° C for 2 minutes to form a conductive polymer film .

Example  2

Polystyrene sulfonic acid having a sulfonation degree of 75% was prepared in the same manner as in Example 1.

Example  3

Polystyrene sulfonic acid having a sulfonation degree of 78% was prepared in the same manner as in Example 1 above.

Example  4

Polystyrene sulfonic acid having a sulfonation degree of 75% and a molecular weight of 250,000 was prepared in the same manner as in Example 1 above.

Example  5

Polystyrene sulfonic acid having a sulfonation degree of 75% and a molecular weight of 700,000 was prepared in the same manner as in Example 1 above.

Example  6

Polystyrene sulfonic acid having a sulfonation degree of 75% and a molecular weight of 700,000 was prepared in the same manner as in Example 1 above. The pressure inside the reactor was maintained at 30 Torr by using a vacuum pump instead of nitrogen gas and deaerated.

Comparative Example  One

Polystyrene sulfonic acid having a degree of sulfonation of 80% was prepared in the same manner as in Example 1.

Comparative Example  2

Polystyrene sulfonic acid having a sulfonation degree of 85% was prepared in the same manner as in Example 1.

Comparative Example  3

Polystyrene sulfonic acid having a degree of sulfonation of 90% was prepared in the same manner as in Example 1 above.

Comparative Example  4

Polystyrene sulfonic acid having a degree of sulfonation of 95% was prepared in the same manner as in Example 1 above.

Comparative Example  5

Polystyrene sulfonic acid having a sulfonation degree of 95% and a molecular weight of 250,000 was prepared in the same manner as in Example 1 above.

Comparative Example  6

Polystyrene sulfonic acid having a sulfonation degree of 95% and a molecular weight of 700,000 was prepared in the same manner as in Example 1 above.

Comparative Example  7

Polystyrene sulfonic acid having a sulfonation degree of 95% and a molecular weight of 700,000 was prepared in the same manner as in Example 1 above. The pressure inside the reactor was maintained at 30 Torr by using a vacuum pump instead of nitrogen gas and deaerated.

Experimental Example  1: Measurement of the viscosity of the reaction solution and the completed conductive polymer solution before the initiation of the reaction

In the above Examples 1 to 6 and Comparative Examples 1 to 7, viscosity measurement was performed on the reaction solution before starting the reaction and the conductive polymer solution after completion of the initiation reaction. The results are shown in Table 1 below. The viscosity measurement method is described below.

Method of viscosity measurement: Brookfield Engineering Laboratories, Inc. Using a V-II + Pro Viscometer, Inc., at a solids concentration of 1% (25 ° C).

Before starting the reaction
The viscosity of the reaction solution (cp) Completed
Conductive polymer solution viscosity (cp) Example 1 1.4 2.2 Example 2 2.1 2.9 Example 3 3.8 4.1 Example 4 32.1 41.7 Example 5 42.5 54.8 Example 6 42.3 54.7 Comparative Example 1 6.8 8.5 Comparative Example 2 10.3 11.8 Comparative Example 3 13.5 14.8 Comparative Example 4 15.1 17.2 Comparative Example 5 39.4 45.5 Comparative Example 6 58.6 70.8 Comparative Example 7 58.4 70.9

As shown in Table 1, the viscosity of the reaction solution before starting the reaction in Examples 1 to 6 according to the present invention is higher than that of Comparative Examples 1 to 7 when the ionic polymer electrolyte having the same molecular weight has a high degree of sulfonation And it was confirmed that Examples 1 to 6 according to the present invention having low sulfonation degree exhibited a low viscosity even when compared with the conductive polymer solution that had been reacted. Also, when the degree of sulfonation was 80% or more, it was confirmed that the viscosity of the reaction solution increased sharply before the initiation of the reaction. Thus, it was confirmed that the viscosity of the reaction solution and the prepared conductive polymer solution can be lowered by adjusting the sulfonation degree of the ionic polymer electrolyte within the range of 70 to 78%. Also, it was confirmed that the higher the molecular weight, the higher the viscosity of the reaction solution before the reaction and the reacted conductive polymer, despite the same degree of sulfonation.

Experimental Example  2: Degassing degree  Measure

In the above Examples 1 to 6 and Comparative Examples 1 to 7, the deaeration degree of the reaction solution was measured before the start of the reaction. Specifically, deaeration was measured at the point where the oxygen concentration before the monomer injection was unchanged. The results are shown in Table 2 below. At this time, the measurement method of deaeration is described below.

Measuring method of degassing: Mettler-Toledo (Korea) Ltd. After measuring the oxygen concentration using InPro 6850i, the amount of dissolved oxygen dissolved in the solvent was calculated based on the amount of oxygen in the air.

Degassing rate (%) Example 1 99.97 Example 2 99.96 Example 3 99.95 Example 4 99.94 Example 5 99.93 Example 6 99.91 Comparative Example 1 99.94 Comparative Example 2 99.93 Comparative Example 3 99.90 Comparative Example 4 99.86 Comparative Example 5 98.96 Comparative Example 6 98.75 Comparative Example 7 98.28

As can be seen from Table 2, the reaction solutions measured in Examples 1 to 6 according to the present invention had lower sulfonation degree at the same molecular weight as compared with the reaction solutions measured in Comparative Examples 1 to 7, It was confirmed that the lower the molecular weight in the sulfonation degree, the higher the deaeration. From these results, it was confirmed that the viscosity had a great influence on the deaeration. Therefore, it can be confirmed that the conductive polymer solution according to the present invention can lower the viscosity by controlling the sulfonation degree of the ionic polymer electrolyte within the range of 70 to 78%, thereby facilitating the degassing.

In addition, excellent surface roughness and haze prevention effect can be expected also for the conductive polymer film prepared by curing the conductive polymer solution through high deaeration.

Experimental Example  3: Electrical Conductivity Measurement of Conductive Polymer Film

Electrical conductivity measurements were performed on the films prepared by curing the conductive polymer solution prepared in Examples 1 to 6 and Comparative Examples 1 to 7. The results are shown in Table 3 below.

Electrical Conductivity (S / cm) Example 1 687 Example 2 692 Example 3 694 Example 4 741 Example 5 787 Example 6 734 Comparative Example 1 686 Comparative Example 2 685 Comparative Example 3 689 Comparative Example 4 690 Comparative Example 5 740 Comparative Example 6 768 Comparative Example 7 731

As shown in Table 3, the conductive polymer films prepared in Examples 1 to 6 according to the present invention had almost the same electrical conductivity values as those of the conductive polymer films prepared in Comparative Examples 1 to 7 I could. This makes it possible to achieve an equivalent level of electrical conductivity in a more effective and economical manner by using an ionic polymer electrolyte having a sulfonation degree of 70 to 78% without using a conventional high ionic polymer electrolyte having a sulfonation degree of at least 80% It is confirmed that it can be implemented.

Claims (10)

A conductive polymer and an ionic polymer electrolyte,
The sulfonation degree of the ionic polymer electrolyte is 70 to 78%
Wherein the dehydration is 97 to 99.98%, the method comprising:
Wherein the conductive polymer solution has a viscosity of 1 to 100 cp when the conductive polymer is contained at a concentration of 1 wt%.
delete The method according to claim 1,
Wherein the viscosity of the conductive polymer solution satisfies the following general formula (1): < EMI ID =
[Formula 1]
(S2 - S1) / S2 x 100? 20%
In the general formula 1,
S1 is the viscosity of a conductive polymer solution prepared using an ionic polymer electrolyte having a degree of sulfonation of 70 to 78%
S2 is the viscosity of a conductive polymer solution prepared using an ionic polymer electrolyte having a sulfonation degree of 80% or more.
The method according to claim 1,
Wherein the molecular weight of the ionic polymer electrolyte is 20,000 to 1,000,000.
The method according to claim 1,
Wherein the ionic polymer electrolyte comprises a monomeric anion or a polyanion.
The method according to claim 1,
Wherein the conductive polymer comprises a structure represented by the following formula (1): < EMI ID =
[Chemical Formula 1]

In Formula 1,
X and Y each independently represent O, S, Si or N,
R ₁ and R ₂ each independently represent hydrogen, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 3 to 20 carbon atoms, or a heteroaryl group having 2 to 20 carbon atoms,
n is an integer from 2 to 2000,
Alternatively, R ₁ and R ₂ are bonded to each other to represent a fused ring structure.
The method according to claim 6,
In the definition of the formula (1), at least one of X, Y, R ₁ and R ₂ is different from K-1 repeating structure in K (K is an arbitrary integer between 2 and 2000) Wherein the conductive polymer solution is prepared by dissolving the conductive polymer solution in a solvent.
The method according to claim 6,
Wherein the conductive polymer represented by the formula (1) is selected from the following formulas (2) to (4):
(2)

(3)

[Chemical Formula 4]

In the above Chemical Formulas 2 to 4,
and n is an integer of 2 to 2000.
A cured coating film of a conductive polymer solution prepared by the method according to claim 1.
10. The method of claim 9,
Wherein the cured coating film has an electrical conductivity of 600 S / cm or more.