JP2546617B2 - Conductive polymer compound with improved temperature characteristics - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive polymer compound having an improved temperature characteristic, more specifically, a conductive polymer compound having an aryl sulfonate substituted with a hydroxyl group as a dopant. The present invention relates to a conductive polymer compound having improved thermal characteristics when used.

[0002]

2. Description of the Related Art Recently, research on conductive polymer compounds has been explosively carried out, and research on its application is also progressing on the other side. In order for conductive polymer compounds to be widely used, various physical properties possessed by conductive polymer compounds should be solved first, but one of the most used methods for improving physical properties is one of them. Is the use of other dopants in the production of conductive polymer compounds. By way of example, the fact that different dopants used in the case of polypyrrole significantly change its electrical conductivity and mechanical properties has already been published (Mol. Cryst.
Liq. Cryst.) 83,1297 (1983)).

The influence of the used dopant on the thermal properties of the conductive polymer compound produced is known. That is, when the dopant used is perchlorate, 2
About 10% of thermal decomposition occurs around 00 ℃, 400
It has been announced that about 35% of the thermal decomposition occurs when heated to ℃ (J.A.
ppl. Polym. Sci.), 43, 573 (1991)). Also, 125 ° C for the change in electrical conductivity of polypyrrole with temperature.
In the case of perchlorate, the conductivity decreased to half after 15 hours, and in the case of toluenesulfonate, it was about 40%.
Is known to be decreased (Macromolecules, 19, 824 (1986)). However, research for improving the thermal properties of conductive polymer compounds has been very small.

[0004]

Generally, in order to apply a conductive polymer compound, it is necessary to maintain its physical properties unchanged even at a high temperature. Ordinary polymer compounds increase the thermal stability of polymer compounds,
Although an antioxidant is added, it is very difficult to use such an antioxidant because the conductive polymer compound is synthesized by an oxidation reaction during the production of the conductive polymer compound. It is more difficult to mix conductive polymer compounds with antioxidants.

[0005]

DISCLOSURE OF THE INVENTION The present inventors have the following structural formula which has a structure similar to that of a substance used as an antioxidant and is sulfonated so that it can also act as a dopant. When the anion of hydroxyaryl sulfonate shown in (I) is used in the production of a conductive polymer compound, such anion is easily mixed into the conductive polymer compound and acts as a dopant having the following structural formula ( The present invention has been completed by focusing on the fact that the conductive polymer compound shown in II) is well maintained in its physical properties even at high temperatures.

Embedded image (In the above formula, M ⁺ is Na ⁺ , K ⁺ , (C ₂ H ₅ ) ₄ N ⁺ or (C ₄ H ₉ ) ₄ N ⁺ , and R ¹ , R ² , R ³ and R ⁴ are Mutually the same or different, each of which is H, methyl, ethyl,
It is one of isopropyl, t-butyl, octyl and dodecyl groups. )

Embedded image (In the above formula, R is NH or S and D is B
_{^{F 4 -, PF 6 -,}} Cl -, Br -, I -, AsF 5 -2, SO 4 -2,
One or more of p-toluene sulfonate, 1-naphthalene sulfonate, and 2-naphthalene sulfonate, wherein the ratio of y to x is 0.1% to 50.
%, And the ratio of z is 0% to 30%. )

In the present invention, one of the anions of the following structural formula (I) and another anion are present together as a dopant, and 0.1% to 50% of the anions of the structural formula (I) are mixed. The present invention provides a conductive polymer compound represented by the following structural formula (II) with improved temperature characteristics:

Embedded image (In the above formula, M ⁺ is Na ⁺ , K ⁺ , (C ₂ H ₅ ) ₄ N ⁺ or (C ₄ H ₉ ) ₄ N ⁺ , and R ¹ , R ² , R ³ and R ⁴ are Mutually the same or different, each of which is H, methyl, ethyl,
It is one of isopropyl, t-butyl, octyl and dodecyl groups. )

[Chemical 6] (In the above formula, R is NH or S and D is B
_{^{F 4 -, PF 6 -,}} Cl -, Br -, I -, AsF 5 -2, SO 4 -2,
One or more of p-toluene sulfonate, 1-naphthalene sulfonate, and 2-naphthalene sulfonate, wherein the ratio of y to x is 0.1% to 50.
%, And the ratio of z is 0% to 30%. ).

The present invention will be described in more detail below. The anion of the above structural formula (I) is used by preparing a hydroxyaryl sulfonate salt by reacting a commercially available phenol derivative in concentrated sulfuric acid and neutralizing the reaction product with a base. . Generally, in the case of conductive polymer compounds such as polypyrrole,
It is said to be most stable when using toluene sulfonate or naphthalene sulfonate as a dopant (Synth. Met., 41,1133 (199
1); Synth. Met., 58,367 (199
3)) Since the hydroxyaryl sulfonate used in the present invention contains all aromatic sulfonate and phenol derivative group, it is superior to the conductive polymer compound having a dopant having different physical properties. Further, as the other anion present as a dopant in the present invention, one or more selected from the group consisting of halogen, persulfate, benzene sulfonate, toluene sulfonate and naphthalene sulfonate are used.

The general method for producing a conductive polymer compound is roughly classified into a chemical polymerization method and an electropolymerization method. In the chemical polymerization method, a monomer and an oxidant are dissolved together and oxidatively polymerized, but when no other anion is present, the anion produced while the oxidant is reduced is used as a dopant and is used as a conductive polymer. Form a compound. If other anions coexist in the solution, each anion is used as a dopant in proportion to its reactivity. Anions such as toluene sulfonate are more often mixed with conductive polymer compounds as dopants than perchlorates or halogen anions. In the present invention, the anion of the above structural formula (I) was shown to have almost similar reactivity as a dopant when compared with toluene sulfonate.

That is, when an appropriately mixed solution of the anion of the structural formula (I) and the monomer is reacted with an oxidizing agent such as ammonium persulfate or ferric chloride, a high conductivity is generated. It was confirmed from the results of FT-IR and elemental analysis that the anion of structural formula (I) was mainly mixed into the molecular compound as a dopant. In addition, when the monomer is polymerized in a solution in which the anion of the structural formula (I) and toluene sulfonate are dissolved in the same ratio, the conductive polymer compound has a substantially same ratio of the toluene sulfonate and the anion of the structural formula (I). It was found to have been used as a dopant in. In this case, pyrrole, aniline, and thiophene can be used as monomers, and ammonium persulfate, ferric perchlorate, ferric perchloride, hydrogen peroxide, oxygen and copper chloride can be used as oxidizing agents. In particular, ammonium persulfate, ferric perchlorate, and ferric perchloride are preferably used as the oxidizing agent.

In the electropolymerization method, a monomer is dissolved in an electrolyte solution to apply a voltage to produce a conductive polymer compound. In this case, the anion of an electrolyte salt present in the solution as a dopant is a conductive polymer. It is mixed with the compound.
In this case, when two or more kinds of anions coexist, they are mixed with the conductive polymer compound in proportion to the reactivity of each dopant. As in the case of chemical polymerization, the anion or the like of the above structural formula (I) is mixed into the conductive polymer compound as a dopant due to its reactivity similar to toluene sulfonate. In electropolymerization, pyrrole and aniline showed the best results.

The results of the thermal decomposition characteristic analysis of polypyrrole using benzene sulfonate and p-cresol sulfonate as dopants are shown in FIGS. 2 and 3, respectively. As can be seen from these results, the polypyrrole-benzene sulfonate of FIG. 2 undergoes thermal decomposition of about 18% at around 200 ° C., and if it is heated to 490 ° C., thermal decomposition of about 45% occurs. It can be seen that the polypyrrole-p-cresol sulfonate of No. 1 causes thermal decomposition of less than 2% up to 190 ° C, and only about 30% of thermal decomposition occurs when heated to 495 ° C. In addition, FIG. 4 shows that the thermal decomposition characteristics of polypyrrole-dimethylphenol sulfonate are superior to those of polypyrrole-benzene sulfonate. The change in conductivity of each conductive polymer compound at 125 ° C. was measured over time and is shown in FIG. As shown in FIG. 5, the electric conductivity of polypyrrole-p-cresol sulfonate was much smaller than that of polypyrrole-toluene sulfonate, and the conductive polymer compound according to the present invention showed a change in conductivity with temperature more than that of the prior art. It turns out that there are few. The molecular weight of a polymer compound is usually 1000
-50000, preferably 1000-25000.

The present invention will now be described based on the following examples.
This will be described in more detail. The present invention is not limited to these examples. In the following example, the electrolyte solution was 0.05M
It can be used at a concentration of 2M.

Example 1 A 0.1 M aqueous solution of ammonium persulfate (150 ml) was added at 0 ° C. to an aqueous solution (100 ml) in which 0.1 M pyrrole and 0.1 M p-cresol sulfonate were dissolved. After the solution was stirred for about 4 hours, the black precipitate formed was filtered with a filter and dried in vacuum. The black powder of polypyrrole-p-cresol sulfonate thus produced was stable in air and the pellets produced by compression had an electric conductivity of about 0.06 S / cm.

Example 2 An aniline-p-cresol sulfonate was prepared in the same manner as in Example 1, but using 0.1M aniline hydrochloride instead of pyrrole. The electric conductivity of the pellets produced by compressing the produced powder is 0.03 S / cm, and this material contains about 2-3% chlorine ions and about 20% cresol sulfonate as dopants. Determined by analysis.

Example 3 A polythiophene was prepared in the same manner as in Example 1, except that 0.1M thiophene was used instead of pyrrole and methanol was used as a solvent. The pellet prepared by compressing the reddish brown powder produced had an electric conductivity of 5 × 10 ⁻³ S / cm.

Example 4 Polypyrrole-p-cresol sulfonate (PPy-PCS) was prepared in a constant current system using an aqueous solution of 0.1 pyrrole and 0.1 M p-cresol sulfonate using a stainless steel working electrode and a negative electrode of a stainless mesh. Manufactured by. The current density used was 1 mA / cm ² ,
The time was 2 hours. The produced polypyrrole film was separated from the electrode and the electric conductivity was measured.
It was S / cm. The FT-IR of this material is shown in FIG. The produced film was washed with pure water and vacuum dried, and then the thermal decomposition characteristics and changes in electrical conductivity with time at 125 ° C. were measured. The results are shown in FIGS. 3 and 5, respectively.

COMPARATIVE EXAMPLE 1 The procedure of Example 4 was repeated except that 0.1M benzene sulfonate was used as the electrolyte salt.
Benzene sulfonate (PPy-BS) was produced. The produced film was washed with pure water, vacuum dried, and then analyzed for thermal decomposition characteristics. The result is shown in FIG.

COMPARATIVE EXAMPLE 2 The procedure of Example 4 was repeated except that 0.1M toluene sulfonate was used as the electrolyte salt.
Toluene sulfonate (PPy-OTS) was produced.
The produced film was washed with pure water and vacuum dried, and then the change in electrical conductivity with time at 125 ° C. was measured. The result is shown in FIG.

Comparative Example 3 Polypyrrole-naphthalene sulfonate (PPy-NaS) was prepared using the same conditions as in Example 4, except that 0.1M naphthalene sulfonate was used as the electrolyte salt. The produced film was washed with pure water and vacuum dried, and then the change in electrical conductivity with time at 125 ° C. was measured. The result is shown in FIG.

Example 5 The procedure of Example 4 is repeated except that 0.1 Mp-
Polypyrrole-dimethylphenol sulfonate (PPy-DMPS) was prepared using 0.1M dimethylphenol sulfonate instead of cresol sulfonate. Its electrical conductivity was 28 S / cm. The produced film was washed with pure water and vacuum dried, and then the thermal decomposition characteristics and changes in electrical conductivity with time at 125 ° C. were measured. The results are shown in FIGS. 4 and 5, respectively.

Example 6 The procedure of Example 4 is repeated except that 0.1 Mp-
Using 0.1M 6-hydroxynaphthalene sulfonate instead of cresol sulfonate, polypyrrole-
6-Hydroxynaphthalene sulfonate was prepared. The electrical conductivity of this compound was 57 S / cm.

Example 7 The procedure is as in Example 4, but polymerizing with 0.1 M aniline instead of pyrrole and polyaniline-p-cresol sulfonate by the constant current method at a current density of 1 mA / cm ^2. Was manufactured. The electric conductivity of the produced film was 62 S / cm, and elemental analysis showed that the chlorine ion content was less than 1%.

Example 8 The procedure of Example 5 was repeated, except that 0.1 M aniline was used instead of pyrrole to polymerize polyaniline by a constant current method at a current density of 1 mA / cm ² .
The electric conductivity of the produced film was 30 S / cm, and elemental analysis showed that the chlorine ion content was less than 1%.

Example 9 The procedure of Example 6 was repeated, except that 0.1 M aniline was used in place of pyrrole to polymerize polyaniline by a constant current method at a current density of 1 mA / cm ² .
The electrical conductivity of the produced film was 55 S / cm, and elemental analysis showed that the chloride ion content was less than 1%.

Example 10 A polypyrrole was prepared by the same method as in Example 4, except that 0.1 M p-cresol sulfonate and 0.1 M toluene sulfonate were used together as electrolytes.
As a result of elemental analysis, it was found that toluene sulfonate and p-cresol sulfonate were mixed in almost the same amount as the dopant. The electrical conductivity of this compound is 60 S / cm
Met.

Example 11 A polypyrrole was prepared by the same method as in Example 5, except that 0.1M toluenesulfonate was used as an electrolyte. As a result of elemental analysis, it was found that toluene sulfonate and dimethylphenol sulfonate were mixed in almost the same amount as the dopant. The electrical conductivity of this compound was 44 S / cm.

EXAMPLE 12 The procedure of Example 6 is repeated, except that 0.1M 6-hydroxynaphthalene sulfonate and 0.1 M are used as electrolytes.
Polypyrrole was prepared together with M toluene sulfonate. As a result of elemental analysis, it was found that toluene sulfonate and 6-hydroxynaphthalene sulfonate were mixed in almost the same amount as the dopant. The electrical conductivity of this compound was 68 S / cm.

[0028]

EFFECTS OF THE INVENTION According to the present invention, a conductive polymer compound is synthesized by using an anion of structural formula (I) as a dopant, so that it has more thermal stability than conventional conductive polymer compounds. Not only is it excellent, but the change in electrical conductivity is small at high temperatures, and the electrical conductivity is good.

[Brief description of drawings]

FIG. 1 is an FT-IR spectrum of polypyrrole-p-cresol sulfonate prepared in Example 4.

FIG. 2 is a graph showing the thermal decomposition characteristics of polypyrrole-benzene sulfonate prepared in Comparative Example 1.

FIG. 3 is a graph showing thermal decomposition characteristics of polypyrrole-p-cresol sulfonate prepared in Example 4.

4 is a graph showing thermal decomposition characteristics of polypyrrole-dimethylphenol sulfonate prepared in Example 5. FIG.

FIG. 5 is a graph showing changes in electric conductivity of polypyrroles manufactured in Examples 4 and 5 and Comparative Examples 2 and 3 with time at 125 ° C.

Front Page Continuation (72) Inventor Chang Jin Lee, Korea, Daejeong-si, Su-gu, Domadon No. 211 Kunnam Apartment 101 -1008 (56) Reference JP-A-62-119237 (JP, A)

Claims (3)

(57) [Claims] 1. One of the anions of the following structural formula (I) and the other anion are present together as a dopant, and 0.1% to 50% of the anions of the structural formula (I) are mixed. Conductive polymer compound represented by the following structural formula (II) with improved temperature characteristics, characterized by: (In the above formula, M ⁺ is Na ⁺ , K ⁺ , (C ₂ H ₅ ) ₄ N ⁺ or (C ₄ H ₉ ) ₄ N ⁺ , and R ¹ , R ² , R ³ and R ⁴ are Mutually the same or different, each of which is H, methyl, ethyl,
It is one of isopropyl, t-butyl, octyl and dodecyl groups. ) (In the above formula, R is NH or S and D is B
_{^{F 4 -, PF 6 -,}} Cl -, Br -, I -, AsF 5 -2, SO 4 -2,
One or more of p-toluene sulfonate, 1-naphthalene sulfonate, and 2-naphthalene sulfonate, wherein the ratio of y to x is 0.1% to 50.
%, And the ratio of z is 0% to 30%. ). 2. The conductive polymer compound according to claim 1, wherein the conductive polymer compound is polypyrrole, polyaniline or polythiophene. 3. The another anion is one or more selected from the group consisting of halogen, persulfate, benzene sulfonate, toluene sulfonate and naphthalene sulfonate.
The conductive polymer compound according to.