JPH0416489B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention provides highly conductive compositions using poly2,5
-Regarding a method for producing thienylene vinylene.

<Prior art> Poly 2,5-thienylenevinylene is known as a linear conjugated polymer, and its production method involves the reaction of a diphosphonium salt and dialdehyde.
It is known that it can be synthesized by the Wittig reaction method etc. (Macromolecular Chemie Vol. 131, p. 15 (1970). It is also known that the polymer sulfonium salt obtained by polymerizing a disulfonium salt with a base is heat-treated. A method for obtaining poly-2,5-thienylenevinylene is also known (Japanese Patent Application Laid-open No. 148231-1982).

<Problems to be Solved by the Invention> However, the former poly 2,5-thienylene vinylene is produced in powder form, and the polymers, except for low polymers, are insoluble and infusible, and as it is, it forms a film or fiber. It is virtually impossible to mold the powder into a shape, and even using special powder molding methods, no useful molded product has been obtained. In addition, the electrical conductivity of a composition doped with film-like poly 2,5-thienylene vinylene obtained from the latter precursor having a sulfonium salt in its side chain is at most 15 S/cm, which is high enough to be used as a conductive material. It cannot be said to be conductive.

The inventors have found that poly2, which provides higher conductivity,
As a result of intensive studies on methods for obtaining 5-thienylenevinylene, we found that a precursor having an ester group in the side chain has excellent solubility and stability in organic solvents, provides a homogeneous film-like molded product, and has an ester group in the precursor. Poly 2,5 has higher conductivity than conventional poly 2,5-thienylene vinylene due to removal of side chains.
- It has been found that it can be converted to thienylene vinylene.

An object of the present invention is to provide a method for producing poly 2,5-thienylene vinylene which exhibits excellent moldability and high conductivity.

<Means for solving the problems> That is, the present invention substantially solves the problem by solving the general formula (A) and general formula (B) R1: Hydrocarbon group having 1 to 10 carbon atoms R2: Consisting of repeating units represented by hydrogen or hydrocarbon groups having 1 to 10 carbon atoms, and the number of (A) units is 2 or more, and the number of (B) units is 2 or more and the number of (A) units/the number of (B) units = 0.05 to 9. Provided is a method for producing poly 2,5-thienylene vinylene containing as a major repeating unit.

The present invention will be explained in detail below.

In the present invention, as a precursor of poly 2,5-thienylene vinylene, substantially the general formula (A) is used. and general formula (B) R1: Hydrocarbon group having 1 to 10 carbon atoms R2: Consisting of repeating units represented by hydrogen or hydrocarbon groups having 1 to 10 carbon atoms, and the number of (A) units is an integer of 2 or more, (B) units is an integer of 2 or more and the number of (A) units/the number of (B) units = 0.05 to 9. A precursor of a conjugated polymer having an ester group in the side chain is used.

In general formula (1), R ₁ is a hydrocarbon group having 1 to 10 carbon atoms,
Examples include methyl, ethyl, propyl, isopropyl, n-butyl, 2-ethylhexyl, phenyl, and cyclohexyl groups, but hydrocarbon groups having 1 to 6 carbon atoms are preferred.

In the precursor of the present invention, in the above formula (1), R ₂ is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, 2
- Hydrocarbon groups having 1 to 6 carbon atoms, including ethylhexyl, phenyl, cyclohexyl groups, etc.
Particularly preferred are methyl and ethyl groups.

Although there are no particular limitations on the method for synthesizing the polymer precursor used in the present invention, the sulfonium salt decomposition method described below is particularly preferred since poly-2,5-thienylenevinylene having higher conductivity can be obtained.

The monomer used in the sulfonium salt decomposition method has the general formula (C) R3, R4: Hydrocarbon group having 1 to 10 carbon atoms A _- : 2,5-thienylene dimethylene bissulfonium salt represented by a counter ion, R3 and R4 are hydrocarbon groups having 1 to 10 carbon atoms, such as methyl , ethyl, propyl,
Examples include isopropyl, n-butyl, 2-ethylhexyl, phenyl, cyclohexyl, benzyl groups, etc., especially hydrocarbon groups having 1 to 6 carbon atoms,
Methyl and ethyl groups are preferred.

Any counter ion A ⁻ of the sulfonium salt can be used. For example, halogen, hydroxyl, boron tetrafluoride, perchloric acid, carboxylic acid, sulfonate ions, etc. can be used, and among them, halogen and hydroxyl ions such as chlorine, bromine, and iodine are preferred.

The solvent for condensation polymerization is water, alcohol alone,
Also, mixed solvents containing water and/or alcohol are used, but solvents containing water are preferred in order to increase the solubility of the alkali.

The alkaline solution used for condensation polymerization is preferably a strongly basic solution with a pH of 11 or higher, and examples of the alkali include sodium hydroxide, potassium hydroxide, calcium hydroxide, quaternary ammonium salt hydroxide, sulfonium salt hydroxide, and strong basic solutions. Ion exchange resins (OH type) can be used, and sodium hydroxide, potassium hydroxide, and strongly basic ion exchange resins are preferably used.

Sulfonium bases are sensitive to heat, light, ultraviolet rays, and strong basic conditions, and desulfonium salts gradually occur after polymerization, making it impossible to effectively substitute ester groups. Therefore, condensation polymerization reactions are carried out at relatively low temperatures.
That is, it is preferable to carry out the reaction at a temperature of 25°C or lower, particularly 5°C or lower. The reaction time may be appropriately determined depending on the polymerization temperature and is not particularly limited, but is usually within the range of 1 minute to 50 hours.

According to this production method, after polymerization, the polymer precursor is first converted into a sulfonium salt, i.e. The sulfonium salt side chain reacts with the organic acid ion (R ₁ COO ^- ) added to the solvent, forming an ester from the organic acid. The group [corresponding to OCOR ₁ in formula (1)] becomes a side chain.

Therefore, in the solvent used, the above R ₁ COO ^-
It is essential to add organic acid ions corresponding to These organic carboxylic acid ions are used by adding an organic carboxylic acid or an alkali metal salt thereof to the polymerization solution during or after the polymerization, but it is preferable to add the organic carboxylic acid or an alkali metal salt thereof after the polymerization because a high molecular weight polymer can be obtained.
The amount of organic carboxylic acid ion used is preferably 0.1 to 50 times equivalent to the sulfonium base.
1 to 20 times the equivalent amount is more preferable. R ₁ of the organic carboxylic acid used is an alkyl group having 1 to 10 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-
Examples include butyl, 2-ethylhexyl, phenyl, and cyclohexyl groups, but hydrocarbon groups having 1 to 6 carbon atoms are preferred. The sulfonium salt side chain reacts with water or alcohol (R ₂ OH) used in polymerization or dialysis treatment to provide a precursor with a hydroxyl group or alkoxy group (-OR ₂ ) as a side chain, thus hindering the substitution reaction with an ester group. . Since the alkoxy group substitution reaction inhibits the ester group substitution reaction more strongly than the hydroxyl group substitution reaction, in order to efficiently carry out the ester group substitution, use water or water/water as a solvent.
It is effective to use an alcohol mixed solvent, and a higher water content is preferred because it is more effective for substitution with ester groups.

In the substitution reaction with an ester group, the temperature is preferably 0°C to 50°C, more preferably 0°C to 50°C from the viewpoint of reaction rate.
It is 25℃. Since polymers having ester groups in their side chains are generally insoluble in the mixed solvent used, they precipitate as the reaction progresses. Therefore, it is effective to carry out the reaction until sufficient precipitation occurs, preferably 15 minutes or more, more preferably 1 hour or more.

The polymer precursor thus obtained is separated by filtering the precipitated product. This polymer precursor has an ester group in its side chain, and the content of the ester group can be easily determined by H-NMR measurement. When the obtained precipitate was dissolved in deuterium-substituted dimethyl sulfoxide, 4.8 and 4.5 ppm
The signal of methine group substituted with alkoxy group and hydroxyl group can be seen in , but the signal of ester group is 6.0.
A signal can be seen around 5.8ppm. The content can be determined from this signal intensity ratio. 4.8 and
The ratio (A/B) of the sum of signal intensities at 4.5 ppm (B) and the sum of signal intensities at 6.0 and 5.8 ppm (A) is 0.05 or more, which is effective for solubility and stability. Since the substitution is not industrially practical, the number is 9 or less, more preferably 0.1 to 4.

In order to obtain a conjugated polymer that provides high conductivity, it is preferable that the molecular weight of the polymer precursor is sufficiently large, and at least n+m of the polymer precursor of general formula (1)
having 4 or more, preferably 10 to 50,000,
For example, those having a molecular weight that cannot be dialyzed by a dialysis membrane with a molecular weight cutoff of 3500 or more are effectively used.

A feature of the present invention is that the polymer precursor having an ester group in its side chain is insoluble in water, but soluble in organic solvents such as dimethylformamide, dimethylacetamide, dimethylsulfoxide, dioxane, and chloroform; A molded article of any shape can be made from the solution, and the poly 2,5-thienylene vinylene produced after the elimination reaction of the ester group provides high conductivity through doping. Any method can be used to obtain the polymer molded article. Regarding its form, for example, a film, fiber, coating film, or any other molded product can be selected. A particularly useful forming method is a method using a polymer precursor solution, which can be used to form a film by casting or into a fiber by solution spinning.
This method involves applying a solution to the substrate. At this time, it is preferable to use a polymer precursor solution from which low molecular weight substances or unreacted substances have been removed in advance by dialysis treatment or reprecipitation treatment.

Poly 2,5-thienylenevinylene can be produced by eliminating side chains (ester groups, hydroxyl groups, and/or alkoxy groups) of a polymer precursor. The side chain elimination treatment can be performed by applying conditions such as heat, light, and ultraviolet rays, but heat treatment is preferable. Further, it is preferable that the removal treatment of the side chain of the polymer precursor is carried out in an inert atmosphere. The inert atmosphere here refers to an atmosphere that does not cause oxidation or other changes in the polymer during processing, and is generally carried out using an inert gas such as nitrogen, argon, helium, etc. You can also do this inside.

When performing side chain removal treatment by heat, heat treatment at too high a temperature will result in decomposition of the poly 2,5-thienylene vinylene produced, and at low temperatures the production reaction is slow and impractical, so the treatment temperature is usually 0. ℃〜
A temperature of 400°C, preferably between 50°C and 350°C is suitable. More preferably, the temperature is 100°C to 320°C. Further, the treatment time can be appropriately selected depending on the treatment temperature, but a range of 1 minute to 10 hours is industrially practical.

The poly 2,5-thienylene vinylene produced in this manner contains 2,5-thienylene vinylene as a main structural unit. According to the production method of the present invention, it is possible to produce poly-2,5-thienylene vinylene having only conjugated repeating units of 2,5-thienylene vinylene, and also It is also possible to produce a polymer containing a lenevinylene skeleton as a part of its constituent units.

In other words, the infrared absorption spectrum shows that the polymer after insufficient elimination treatment still contains a structural unit having a 2,5-thienylene ethylene skeleton in which the ester group is in an incompletely eliminated state. It is observed by et al. In this case, poly-2,5-thienylenevinylene having high flexibility can be produced. Note that the ratio of 2,5-thienyleneethylene units to 2,5-thienylenevinylene units can be changed by arbitrarily devising the manufacturing conditions depending on the purpose of use. For purposes such as conductive polymer materials, the ratio of the latter to the former is preferably 1 or less, more preferably 1/20 or less.

It is also possible to heat-treat a molded product of a polymer precursor by stretching and orienting it. These stretching and orientation treatments can be performed before or simultaneously with the side chain elimination treatment.

Orientation can be achieved by devising a molding method, such as extrusion using high shear force, but high orientation can be imparted by heating and stretching a polymer precursor molded product from a polymer precursor solution. The extent of this stretching orientation can be confirmed by the appearance of infrared dichroism in a polarized infrared spectrum.

Next, the poly 2,5-thienylene vinylene obtained by the side chain elimination treatment in the present invention is used as an electron acceptor or an electron donor (referred to as a dopant).
A highly conductive composition is provided by the action of

As a dopant, a compound that has been found to have an effect of improving conductivity by doping a known conductive polymer compound such as polyacetylene or by forming an intercalation compound of graphite is effectively used, and doping can be done by any method. However, doping is preferably carried out by conventionally known techniques such as chemical doping, electrolytic doping, optical doping, and ion implantation.

Specifically, as electron acceptors, halogen compounds: fluorine, chlorine, bromine, iodine, iodine chloride, iodine trichloride, iodine bromide Lewis acids: phosphorus pentafluoride, arsenic pentafluoride, antimony pentafluoride , boron trifluoride, boron trichloride, boron tribromide, sulfur trioxide Protonic acids: hydrogen fluoride, hydrogen chloride, nitric acid, sulfuric acid, perchloric acid, sulfonic fluoride, sulfonic chloride, methanesulfone trifluoride Acid reduction metal compounds: titanium tetrachloride, zirconium tetrachloride, hafnium tetrachloride, niobium pentachloride,
Tantalum pentachloride, molybdenum pentachloride, tungsten hexachloride, iron trichloride Organic compounds: tetracyanoethylene, tetracyanoquinodimethane, chloranil, dichlorodicyanobenzoquinone Electron donors include alkali metals: lithium, sodium, potassium, Examples include rubidium and cesium quaternary ammonium salts: tetraalkylammonium ions.

Even if the poly 2,5-thienylene vinylene obtained in the present invention is not oriented, it can be doped to provide a highly conductive composition having a conductivity of 20 S/cm or more.

<Effects of the Invention> As explained above, according to the present invention, poly 2,5-thienylene vinylene can be produced which provides a highly conductive composition compared to conventional poly 2,5-thienylene vinylene. Furthermore, the present invention provides poly 2,5-thienylene vinylene having various shapes that can be applied to electrical and electronic materials.

<Example> The present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. ) 4.0 g of 2,5-thienylene-bis(methylenedimethylsulfonium bromide) and 100 g of ion-exchanged water
ml, a mixed solution of 10 ml of 1N NaOH and 30 ml of ion-exchanged water was added dropwise at 0 to 5°C over 30 minutes, and after the dropwise addition, stirring was continued at 0 to 5°C for 30 minutes. A solution prepared by dissolving 16 g of potassium acetate in 50 g of ion-exchanged water was added to this reaction solution, and a reaction with acetate ions was carried out at 0 to 5°C. When left for one day, a yellow precipitate formed. This precipitate was 100% dissolved in dimethylacetamide. Cast from solution,
A precursor film was obtained by drying under a nitrogen stream.

On the other hand, when the obtained precipitate was dissolved in deuterium-substituted dimethyl sulfoxide and H-NMR was measured, proton signals were observed at around 6.0 ppm and 4.8 ppm. As described in Comparative Example 2, the signal at 4.8 ppm reflects hydroxyl group substitution. The newly appeared signal at 6.0 ppm is considered to reflect the structure substituted with an acetyl group.
The ratio of the signal intensity of 4.8 ppm to the signal intensity of 6.0 ppm is about 2:1, and the acetyl groups are substituted by about 33%. Furthermore, in the infrared absorption spectrum of the obtained precursor, absorption of ester bond was observed at 1740 cm ^-1 . These analysis results confirmed that the precursor polymer had an acetyl group in its side chain in addition to a hydroxyl group. Further, the degree of polymerization was measured by gel permeation chromatography using dimethylformamide as a solvent, and the degree of polymerization determined from the number average molecular weight in terms of polystyrene was 1200.

Example 1 Film obtained in Reference Example 1 (length 2 cm, width 2 cm)
under a nitrogen atmosphere at 200℃ using a horizontal tube furnace.
A stationary heat treatment was performed for 30 minutes to obtain a black poly 2,5-thienylene vinylene film having metallic luster. This structure was confirmed based on the elemental analysis data and the characteristic absorption in the infrared absorption spectrum that matched that of the specimen obtained by the Wittig method.

Reference Example 2 When the poly 2,5-thienylene vinylene film obtained in Example 1 was doped with iodine, which is an electron acceptor compound, from the gas phase at room temperature by a conventional method, 26S was obtained in 4 hours. It showed an electrical conductivity of /cm. The electrical conductivity was measured using the four-terminal method.

Reference Example 3 When the poly 2,5-thienylene vinylene film obtained in Example 1 was doped with sulfur trioxide using 30% fuming sulfuric acid as a source, 21 S/cm
The conductivity was .

Reference Example 3 The film of poly 2,5-thienylenevinylene obtained in Example 1 was electrolytically doped using a 0.5N LiC104-acetonitrile solution as the electrolyte. The resulting film turned glossy black and was conductive. The degree was 18S/cm.

Comparative Example 1 4.0g of 2,5-thienylene-bis(methylenedimethylsulfonium bromide) was added to ion-exchanged water.
After dissolving in 100 ml, a mixed solution of 10 ml of 1N NaOH and 30 ml of ion-exchanged water was added dropwise at 0 to 5°C over 30 minutes, and stirring was continued at 0 to 5°C for 30 minutes after the dropwise addition. When this reaction solution was allowed to stand for one day, a yellow precipitate was formed. This precipitate was dissolved 30% in dimethylformamide. Cast from the obtained solution,
A precursor film was obtained by drying under a nitrogen stream.

On the other hand, when the obtained precipitate was dissolved in deuterium-substituted dimethyl sulfoxide and H-NMR was measured, it was found that the signal was a methine group substituted with a hydroxyl group.
A proton signal was seen around 4.8 ppm.

The obtained film (length 2 cm, width 2 cm) was subjected to static heat treatment in a nitrogen atmosphere at 200°C for 30 minutes using a horizontal tubular furnace to produce a black poly 2,5-thienylene vinylene with metallic luster. I got the film. When this film was doped with iodine, which is an electron acceptor compound, from the gas phase at room temperature by a conventional method, it showed an electrical conductivity of 21 S/cm in 5 hours.

Reference Example 4 (Production of poly 2,5-thienylene vinylene precursor) 4.0 g of 2,5-thienylene-bis(methylenedimethylsulfonium bromide) was added to 100 ml of a mixed solvent of ion-exchanged water and methanol (volume ratio 1:1). After dissolving, a mixed solution of 10 ml of 1N NaOH and 30 ml of methanol was added dropwise at -30°C over 30 minutes, and stirring was continued at -30°C for 1 hour after the dropwise addition. This reaction solution was neutralized with HBr. Add potassium acetate to this solution.
A solution obtained by dissolving 20 g of the solution in 50 g of ion-exchanged water was added, and a reaction with acetate ions was carried out at 0 to 5°C. When left for one day, a yellow precipitate formed. This precipitate was approximately 100% dissolved in dimethylformamide.
A precursor film was obtained by casting from the solution and drying under a nitrogen stream.

On the other hand, when the obtained precipitate was dissolved in deuterium-substituted dimethyl sulfoxide and H-NMR was measured, proton signals were observed at around 6.0 ppm, 5.8 ppm, 4.8 ppm, and 4.5 ppm. As described in Comparative Example 2, the signals at 4.8 and 4.5 ppm are due to alkoxy groups and hydroxyl groups. The new 6.0
The signal at 5.8 ppm is thought to reflect the structure in which the acetyl group is substituted. The ratio of the signal intensities of 4.8 and 4.5 ppm to the signal intensities of 6.0 and 5.8 ppm is about 3:1, and the acetyl groups are substituted by about 25%. Furthermore, in the infrared absorption spectrum of the obtained precursor, absorption of ester bond was observed at 1740 cm ^-1 . From these analysis results, it was confirmed that the precursor polymer had an acetyl group in its side chain in addition to an alkoxy group and a hydroxyl group.

Example 2 Film obtained in Reference Example 4 (length 2 cm, width 2 cm)
under a nitrogen atmosphere at 200℃ using a horizontal tube furnace.
A stationary heat treatment was performed for 30 minutes to obtain a black poly 2,5-thienylene vinylene film with metallic luster. This structure was confirmed because the elemental analysis values and the characteristic absorption in the infrared absorption spectrum matched those of the specimen obtained by the Wittig method.

Reference Example 5 When the poly-2,5-thienylenevinylene film obtained in Example 2 was doped with iodine, which is an electron acceptor compound, from the gas phase at room temperature by a conventional method, the resultant film was doped in 2 hours. It showed an electrical conductivity of 23S/cm.

Comparative Example 2 7.8 g of 2,5-thienylene-bis(methylenedimethylsulfonium bromide) was dissolved in 200 ml of a mixed solvent of ion-exchanged water and methanol (volume ratio 1:1), and then mixed with 20 ml of 1N NaOH and 80 ml of methanol. The solution was added dropwise at -30°C over 30 minutes, and after the dropwise addition, stirring was continued at -30°C for 30 minutes. This reaction solution was quickly poured into a dialysis membrane (Cerotube, molecular weight fraction 8000, manufactured by Union Carbide) and heated to 0°C.
When the membrane was dialyzed for 1 day by immersing it in a water-methanol mixed solvent (1:1) cooled to 100 mL, a yellow precipitate was formed within the dialysis membrane. This precipitate was approximately 80% dissolved in dimethylformamide. The obtained solution was cast and dried under a nitrogen stream to obtain a precursor film. It is also dissolved in deuterium-substituted dimethyl sulfoxide, and in H-NMR it is a signal of methine group at the site substituted with alkoxy group or hydroxyl group.
Proton signals were seen around 4.8 and 4.5 ppm, but other signals were unclear due to water and solvent. In the infrared absorption spectrum of the obtained precursor,
Absorption of ether bond was observed at 1100 cm ^-1 . From these analysis results, it was confirmed that the precursor polymer had a methoxy group in its side chain.

Reference Example 6 (Production of precursor of poly 2,5-thienylene vinylene) After dissolving 4.0 g of 2,5-thienylene-bis(methylenedimethylsulfonium bromide) in 50 ml of a mixed solvent of ion-exchanged water and methanol, -30
Cooled to ℃. Next, a strongly basic ion exchange resin (Amberlite IRA-401) which had been converted into an OH type in advance in an amount equivalent to twice the amount of the sulfonium salt,
(manufactured by Rohm and Haas) was gradually added over 10 minutes, and stirring was continued at -30°C for 50 minutes.

After the reaction, the reaction solution was separated from the ion exchange resin, the temperature of the filtrate was raised to 0°C, a solution of 20g of sodium n-butyrate dissolved in 50g of ion-exchanged water was added, and the mixture was heated to 0°C.
When the mixture was left for 10 hours, a yellow precipitate formed.
This precipitate was dissolved in dimethylformamide and reprecipitated with water. The obtained precipitate was dissolved in dimethylformamide to obtain a cast film. When the H-NMR spectrum of this precursor film was measured using deuterium-substituted dimethyl sulfoxide as a solvent, proton signals were observed at 6.0, 5.8, 4.8, and 4.5 ppm. In addition, when the degree of polymerization was measured by gel permeation chromatography using dimethylformamide as a solvent, the degree of polymerization determined from the number average molecular weight in terms of polystyrene was 830.
It was hot.

Example 3 The polymer precursor film obtained in Reference Example 6 was heated and stretched to 200° C. under nitrogen flow to obtain a poly 2,5-thienylene vinylene stretched film stretched five times. The characteristic absorption of the infrared absorption spectrum of this film matched that obtained in Example 1, and it was found that it exhibited infrared dichroism and was oriented.

Reference Example 7 When the poly-2,5-thienylenevinylene film obtained in Example 3 was doped with iodine, which is an electron acceptor compound, from the gas phase at room temperature by a conventional method, a film of 1140 S/cm was obtained. It showed electrical conductivity.

Claims (1)

[Claims] 1 General formula (A) and general formula (B) R1: Hydrocarbon group having 1 to 10 carbon atoms R2: Consisting of repeating units represented by hydrogen or hydrocarbon groups having 1 to 10 carbon atoms, and the number of (A) units is an integer of 2 or more, (B) units is an integer of 2 or more, and the side chain of a polymer precursor having a structure in which the number of (A) units/the number of (B) units = 0.05 to 9 is subjected to elimination treatment. A method for producing highly conductive poly 2,5-thienylene vinylene containing as a main repeating unit. 2 The polymer precursor has the general formula (C) R3, R4: Hydrocarbon group having 1 to 10 carbon atoms A-: A patent obtained by polymerizing a sulfonium salt monomer represented by an ion with an alkali, and then reacting the polymer with organic acid ions. Claim 1
Manufacturing method described in section