KR102270820B1 - Conductive polymer solution and cured product thereof - Google Patents

Abstract

The present invention relates to a conductive polymer solution and a cured coating film thereof, wherein the conductive polymer solution according to the present invention contains a particulate component having a particle size distribution in the range of 50 to 100 nm, thereby producing relatively large particles in a range that does not cause scattering. It has, it is possible to implement high conductivity, and to implement a relatively high viscosity, it is possible to prevent the bonding of the conductive polymer from breaking during the coating operation.

Description

Conductive polymer solution and cured coating film thereof

The present invention relates to a conductive polymer solution and a cured coating film thereof.

As various home appliances and communication devices including computers are digitized and rapidly improved in performance, the 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 the display should not only be transparent and exhibit low resistance, but also have high flexibility to respond to mechanical shock, and short circuit or sheet resistance even when the device is overheated and exposed to high temperatures. change should not be large.

Currently, the most widely used transparent electrode material for display is ITO (indium-tin oxide). However, when the transparent electrode is formed of ITO, there are disadvantages in that excessive cost is consumed and it is difficult to implement a large area. In particular, when ITO is coated on a large area, the change in sheet resistance is large, so that the luminance and luminous efficiency of the display decrease. In addition, indium, the main raw material of ITO, is a limited mineral and is rapidly being depleted as the display market expands.

In order to overcome these disadvantages of ITO, research on forming a transparent electrode using a conductive polymer having excellent flexibility and a simple coating process is being conducted.

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, polymerization of the conductive polymer monomer is caused by mixing a conductive polymer monomer and an ionic polymer electrolyte. In this case, the size of the particles present in the mixture of the conductive polymer monomer and the ionic polymer electrolyte is uniformly prepared. However, since it is an ionic electrolyte, the existing particles are agglomerated with each other and become larger than the size of the originally formed particles, so it is essential to physically separate the agglomerated particles from each other after synthesis. Through this process, a dispersion with a very uniform particle distribution is produced, but when the particles are pulverized too small, it is not easy to assemble such as clustering between the particles during coating, so coating properties are not good, and the need to use additives is cumbersome. It may occur, and it may not be easy to prepare thick films and high conductivity films at a certain viscosity. Therefore, particle size control can be a very important technique when pulverizing particles.

Korean Patent Publication No. 2012-0077112

The present invention relates to a conductive polymer solution and a cured coating film thereof. A conductive polymer solution containing a conductive polymer and an ionic polymer electrolyte includes a particulate component in the solution, wherein the particulate component is within a range of 50 to 100 nm. An object of the present invention is to provide a conductive polymer solution having a particle size distribution.

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

In the conductive polymer solution containing a conductive polymer and an ionic polymer electrolyte,

It contains a particulate component in a solution,

The particulate component may provide a conductive polymer solution having a particle size distribution within a range of 50 to 100 nm.

In addition, the present invention may provide a cured coating film of the conductive polymer solution.

The conductive polymer solution according to the present invention includes a particulate component having a particle size distribution in the range of 50 to 100 nm, and thus has relatively large particles in a range that does not cause scattering, high conductivity, and relatively high viscosity. Thus, it is possible to prevent the bonding of the conductive polymer from breaking during the coating operation.

The present invention relates to a conductive polymer solution and a cured coating film thereof.

As an example of the conductive polymer solution,

In the conductive polymer solution containing a conductive polymer and an ionic polymer electrolyte,

It contains a particulate component in a solution,

The particulate component may provide a conductive polymer solution having a particle size distribution within a range of 50 to 100 nm.

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, the purpose of the present invention is to prepare a conductive polymer solution for realizing high electrical conductivity. However, when the conventional conductive polymer solution contains particles having one average particle size distribution in the range of 50 nm or less, there is a problem in viscosity or conductivity lowering, and one average particle size distribution in the range of more than 100 nm. In the case of including the particles having the particle size, high conductivity can be realized, but there is a problem in that scattering occurs due to the void space generated between the large-sized particles.

However, the conductive polymer solution according to the present invention has particles in a range that does not cause scattering by preparing a conductive polymer solution containing particulate components having different particle size distributions of 50 to 100 nm, and high conductivity can be realized. , by implementing a relatively high viscosity, it is possible to prevent the bonding of the conductive polymer from breaking during the coating operation.

The method for forming particles having an average particle size distribution within the above range is not particularly limited, and for example, it may be formed through a method such as a ball mill grinder, agitation grinder, high-speed stirring, ultrasonic treatment, and pulverization by high pressure homogenization. In these methods, the pulverization power and pulverization time of various strengths may be changed according to the amount, viscosity, concentration, etc. of the pulverization treatment solution, but are not limited thereto.

The particle size distribution of the particulate component within the range of 50 to 100 nm may be 90 parts by weight or more based on 100 parts by weight of the total particulate component. For example, the distribution of the particulate component within the range of 50 to 100 nm in the conductive polymer solution may be 90 parts by weight to 100 parts by weight or 95 parts by weight to 99.9 parts by weight. The distribution of the particulate component within the above range may include 10 parts by weight or less, 5 parts by weight or 3 parts by weight of particles of less than 50 nm and more than 100 nm in the solution. This may mean that the problem due to the size of the particulate component in the existing solution can be reduced.

Through such a particle size distribution of the particulate component, it is possible to prepare a conductive polymer solution capable of implementing high conductivity in a range that does not cause scattering.

The viscosity of the conductive polymer solution may be 30 to 100 cP.

For example, the viscosity may range from 30 to 100 cP, from 40 to 100 cP or from 50 to 95 cP. The viscosity within the above range can be implemented by adjusting the average particle diameter of the particulate component of the conductive polymer solution to 50 to 100 nm within a range that does not cause scattering. Through this, it is possible to prevent the bonding of the conductive polymer from breaking during the conventional coating operation, and when cured and used as a conductive polymer film, a product with high conductivity can be produced.

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

For example, the conductive polymer may include a structure of Formula 1 below.

[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,

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

n is an integer from 2 to 2000;

In this case, 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, a n-propyl group, an iso-propyl group, a n-butyl group, sec-butyl group, t-butyl group, n-pentyl group, 1,1-dimethylpropyl group, 1 ,2-dimethylpropyl group, 2,2-dimethylpropyl group, 1-ethylpropyl group, 2-ethylpropyl group, n-hexyl group, 1-methyl-2-ethylpropyl group, 1-ethyl-2-methylpropyl group group, 1,1,2-trimethylpropyl group, 1-propylpropyl 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, 3-methylpentyl group, etc. are mentioned.

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 phenanathryl group, a naphthacenyl group, a pyrenyl group. , tolyl group, biphenylyl group, terphenylyl group, chrycenyl group, spirobifluorenyl group, fluoranthenyl group, fluorine A fluorenyl group, a perylenyl group, an indenyl group, an azulenyl group, a heptalenyl group, a phenalenyl group, a phenanthrenyl group group) and the like.

In addition, the heteroaryl group represents an aromatic heterocyclic or heterocyclic ring 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 hetero atom.

Specific examples of the heteroaryl group include pyrrolyl group, pyridyl group, pyridazinyl group, pyrimidinyl group, pyrazinyl group, triazolyl group, tetrazolyl group, benzotriazolyl group, pyrazolyl group, imidazolyl group, benz imidazolyl group, indolyl group, thiazolyl group, isothiazolyl group, benzothiazolyl group, benzthiadiazolyl group, phenothiazinyl group, isoxazolyl group, furazanyl group, phenoxazinyl group, oxazolyl group , benzoxazolyl group, oxadiazolyl group, pyrazoloxazolyl group, imidazothiazolyl group, thienofuranyl group, furopyrrolyl group, and compounds containing a hetero atom such as pyridoxazinyl group.

As an example, in the conductive polymer, the K (K is an arbitrary integer between 2 and 2000) th repeating structure of Formula 1 is compared with the K-1 th repeating structure in the definition of Formula 1, X, Y, R ₁ and At _{least one of R 2} may be different. For example, the conductive polymer represented by the structure of Formula 1 may be selected from structures of Formulas 2 to 4 below.

[Formula 2]

[Formula 3]

[Formula 4]

In Formulas 2 to 4,

n is an integer from 2 to 2000;

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

For example, the conductive polymer may be uncharged or cationic. Here, "cation" may relate only to the charge present on the main chain. Accordingly, the conductive polymer may need an anion to compensate for the positive charge. The anion may be obtained from an ionic polymer electrolyte, and examples of the ionic polymer electrolyte may include a monomer anion or a polyanion having a molecular weight of 20,000 to 1,000,000.

As an example of the monomer anion, C ₁ -C ₂₀ -alkanesulfonic acid, aliphatic perfluorosulfonic acid, aliphatic C ₁ -C ₂₀ -carboxylic acid, aliphatic perfluorocarboxylic acid, C _-1 -C ₂₀ -alkyl group Substituted aromatic sulfonic acid, cycloalkanesulfonic acid, iron sulfate, sodium persulfate, tetrafluoroborate, hexafluorophosphate, perchlorates, hexafluoroantimonate, hexafluoro roasenates (hexafluoroarsenates) or hexachloroantimonates.

Examples of the polyanion include anions of polymeric carboxylic acids (e.g., polyacrylic acid, polymethacrylic acid or polymaleic acid), polymeric sulfonic acids (e.g., polystyrenesulfonic acid and polyvinylsulfonic acid) and poly(styrene). sulfonic acid-co-maleic acid). Specifically, the ionic polymer electrolyte may be polystyrene sulfonic acid having a molecular weight of 20,000 to 1,000,000. Through this, ions such as cations and anions may exist in the solution in the process of forming the bonding structure.

The solution containing the conductive polymer and the ionic polyelectrolyte 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 an organic compound containing oxygen and nitrogen.

The ammonium salt electrolyte may include, for example, one or more 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, one or more of _{NaPF 6} , NaBF ₄ and NaClO _{4 .}

The lithium salt electrolyte is, 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, and the like.

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

The sulfonic acid compound is, for example, alkanesulfonic acid having 1 to 20 carbon atoms, perfluoroalkanesulfonic acid having 1 to 20 carbon atoms, alkylhexylcarboxylic acid having 1 to 20 carbon atoms, purple having 1 to 20 carbon atoms. It may include at least one of luoroalkanecarboxylic acid, aromatic sulfonic acid unsubstituted or substituted by an alkyl group having 1 to 20 carbon atoms, and cycloalkanesulfonic acid (eg, camphorsulfonic acid).

Specifically, the sulfonic acid compound is 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, ninonylnaphthalenedisulfonic acid and camphorsulfonic acid and one or more of phonic acids.

The dopant may be used singly or by mixing two or more dopants.

For example, the dopant may include a single type or two or more types of sulfuric acid and sulfonic acid compounds.

The dopant may be dissolved in a solvent and mixed.

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

The method for preparing the conductive polymer solution is not particularly limited, and may be prepared through a conventionally performed method. For example, it can be prepared by providing means for preventing peroxidation of the conductive polymer during the manufacturing process of the conductive polymer solution.

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

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

The conductivity of the prepared cured coating film may be 1000 S/cm or more. For example, the conductivity may be in the range of 1100 to 4000 S/cm, 1100 to 3000 S/cm, or 1200 to 2500 S/cm. The conductivity in the above range is a value improved by about 5% or more compared to a cured coating film prepared using a conventional conductive polymer solution containing particles having a single average particle diameter of less than 50 nm.

Specifically, it was confirmed that 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 sheet resistance, and through this, when applied to an electronic device, high performance can be realized.

The resistance of the formed cured coating film may have a resistance variation of less than 10% at a plurality of different positions. Specifically, when the conductive polymer film is prepared by curing the conductive polymer solution having the particle distribution according to the present bar bottle, the surface uniformity is relatively excellent, so that the resistance variation can be less than 10%. For example, the resistance variation may be 0.1 to 9.5%, 3 to 9.5%, or 3 to 8%.

The surface average roughness of the cured coating film may be less than 5 nm. For example, the average roughness may be measured after forming a 3D image from a profile obtained through an atomic force microscope (equipment name: Bruker Innova). Specifically, images were taken with a resolution of 512 lines x 512 lines (each line has a resolution of 1 nm) with respect to the area of the cured coating film at a scan rate of 0.2 Hz.

The average roughness can be confirmed by measuring the center line average roughness (Ra). A portion of the measurement length L is taken from the roughness curve of the surface of the hollow fiber membrane in the direction of the center line, the center line of the sampled portion is the X-axis and the direction of vertical magnification is the Z-axis, and the roughness curve is y = Z(x) When expressed as , it may mean a value obtained by Equation 1 below.

[Equation 1]

For example, draw a center line from the roughness curve of the surface of the hollow fiber membrane so that the area below the center line and the area above the center line are the same, then raise the area below the center line to the top of the center line, and cut the protruding part above the center line to fill the valley. When a flat surface is made from a flat surface, the distance between the flat surface and the center line can be called the center line average roughness (Ra).

For example, the surface average roughness may range from 0.1 to 4.5 nm, from 0.5 to 4.5 nm, or from 1 to 4.5 nm. Specifically, by curing the conductive polymer solution according to the present invention, which has excellent surface uniformity due to excellent assembly characteristics between particles, average roughness within the above range can be realized.

Haziness of the cured coating film may be less than 1.3%. For example, the haze may be measured using a haze meter COH 400 manufactured by NIPPON DENSHOKU. In this case, the degree of blur may be 0.1 to 1.2%, 0.1 to 1.1%, or 0.2 to 1%. It can be seen that the cured coating film according to the present invention has a degree of haze within the above range, thereby realizing high transparency as a transparent conductive film.

Hereinafter, the present invention will be described in more detail through Examples and the like according to the present invention, but the scope of the present invention is not limited by the Examples presented below.

Example

In a reaction vessel, 12.53 g of polystyrene sulfonic acid (PSS) was dissolved in 1400 g of distilled water from which oxygen was removed using a membrane degassing machine, and then stirred using an impeller for 2 hours. Then, 0.2 g of iron sulfate was added and stirred until dissolved. When iron sulfate is completely dissolved, lower the temperature of the solution to 13°C, add 5.014 g of 3,4-ethylenedioxythiophene (EDOT) monomer, and 11.9 sodium persulfate 30 g of an aqueous solution in which g was dissolved was added and polymerization was carried out for 24 hours. After the reaction was stopped, 500 ml of a mixed ion exchange resin in which a cation exchange resin and an anion exchange resin were mixed in a 1:1 ratio was added to remove unnecessary ions. Thereafter, the obtained solution was pulverized to particles for 8 minutes using a high-pressure homogenizer. Thereafter, a conductive polymer solution having an average particle size distribution of 60 to 80 nm when measured using CPS Disc Centrifuge equipment was prepared.

Then, prepare the prepared conductive polymer solution as a solution with a concentration of 1.3%, add 5% DMSO solution based on the weight of the solution, mix thoroughly, coat using bar coating, and dry the conductive polymer film at 150°C for 30 minutes. prepared.

comparative example

A conductive polymer film was prepared in the same manner as in Example, except that a conductive polymer solution having a particle size distribution within 1 to 50 nm was used.

Experimental example 1: Viscosity measurement of conductive polymer solution

A viscosity measurement experiment was performed on the conductive polymer solutions prepared in Examples and Comparative Examples using a viscosity meter. The results are shown in Table 1 below.

Viscosity (cP) Example 30 comparative example 20

Referring to Table 1, it was confirmed that the conductive polymer solution prepared in Examples according to the present invention exhibited a viscosity of 30 to 100 cP or less. Specifically, it was found that the conductive polymer solution according to the present invention has a particle size within a range that does not cause scattering, and can solve problems caused by the existing high viscosity.

Experimental example 2: Measurement of physical properties of conductive polymer film

Conductive polymer films prepared in Examples and Comparative Examples were subjected to measurement experiments for conductivity, resistance variation, surface average roughness, and haze. The measurement method is described below, and the results are shown in Table 2 below.

1) Conductivity

Each of the prepared conductive polymer films was prepared as a sample having a size of 100 mm in width and length, and the conductivity of the prepared sample was measured using a conductivity measuring device.

2) resistance variation

For each of the above samples, a total resistance of 50 points was measured using a 4 probe resistance meter.

3) Surface average roughness

For each of the samples, a 3D image was formed from a profile obtained through an atomic force microscope (equipment name: Bruker Innova), and then the centerline average roughness (Ra) was obtained.

4) Blur

For each of the above samples, measurements were made using COH 400, a haze meter manufactured by NIPPON DENSHOKU.

Conductivity (S/cm) Resistance Variation (%) Average Roughness (nm) Blurness (%) Example 1150 9 4 1.2 comparative example 1000 17 5.4 2

Referring to Table 2, it was confirmed that the conductive polymer film prepared in Examples according to the present invention exhibited an improved conductivity value of about 15% compared to the conductive polymer film prepared in Comparative Examples.

In addition, it was confirmed that the conductive polymer film prepared in Examples had a resistance variation of less than 10%, and exhibited a resistance variation that was at most about 1/1.8 times lower than that of the conductive polymer film prepared in Comparative Example.

In addition, it was confirmed that the conductive polymer film prepared in Examples had an average roughness of less than 4 nm, and exhibited an average roughness that was at most about 1/1.4 times lower than that of the conductive polymer film prepared in Comparative Examples.

In addition, it was confirmed that the conductive polymer film prepared in Examples had a haze of less than 1.5%, and exhibited a haze that was at most about 1/1.7 times lower than that of the conductive polymer film prepared in Comparative Examples.

Claims (11)

In the conductive polymer solution containing the conductive polymer and the ionic polymer electrolyte,
It contains a particulate component in a solution,
The particulate component is a conductive polymer solution having an average particle size distribution within a range of 60 to 80 nm.
The method of claim 1,
The conductive polymer solution, characterized in that the average particle size distribution of the particulate component within the range of 60 to 80 nm is 90 parts by weight or more based on 100 parts by weight of the total particles.
The method of claim 1,
The conductive polymer solution has a viscosity of 30 to 100 cP.
The method of claim 1,
The conductive polymer solution is a conductive polymer solution, characterized in that it contains the structure of Formula 1:
[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,
wherein R ₁ and R ₂ are bonded to each other to represent a fused ring structure,
n is an integer from 2 to 2000;
5. The method of claim 4,
In the definition of Formula 1, the K-th repeating structure (K is an arbitrary integer between 2 and 2000) of Formula 1 is different from the K-1-th repeating structure in at least one of X, Y, R ₁ and R ₂ . Conductive polymer solution, characterized in that.
5. The method of claim 4,
The conductive polymer represented by the structure of Chemical Formula 1 is a conductive polymer solution, characterized in that it is selected from the structures of Chemical Formulas 2 to 4.
[Formula 2]

[Formula 3]

[Formula 4]

In Formulas 2 to 4,
n is an integer from 2 to 2000;
A cured coating film of the conductive polymer solution according to any one of claims 1 to 6.
8. The method of claim 7,
A cured coating film, characterized in that the conductivity of the cured coating film is 1000 S/cm or more.
8. The method of claim 7,
A cured coating film, characterized in that the resistance of the formed cured coating film has a resistance variation of less than 10% at a plurality of different positions.
8. The method of claim 7,
A cured coating film, characterized in that the surface average roughness of the cured coating film is less than 5 nm.
8. The method of claim 7,
A cured coating film, characterized in that the haziness of the cured coating film is less than 1.3%.