JPH0360848B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a polymer precursor that can be converted into a conjugated polymer poly-2,5-thienylenevinylene and a method for producing the same.

<Prior art> Poly-2,5-thienylenevinylene is known as a linear conjugated polymer, and its production method involves a reaction between 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)).Also, polymer sulfonium salt precursors obtained by polymerizing disulfonium salts with bases are A method of obtaining the above-mentioned polymer by heat treatment is also known (Japanese Patent Application Laid-open No. 148231/1983).

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

The inventors have discovered that poly-2, which provides higher conductivity,
As a result of intensive studies on the method of obtaining 5-thienylene vinylene, we found that a precursor having an ester group in the side chain is a poly-2,5-thienylene vinylene that gives higher conductivity than conventional poly-2,5-thienylene vinylene by eliminating the ester group.
It has been found that the precursor can be converted to 2,5-thienylenevinylene, has excellent solubility and stability in organic solvents, and can give a homogeneous film-like molded product.

The object of the present invention is to provide poly-2,5 which provides high conductivity.
- To provide a precursor polymer with excellent solubility for producing thienylene vinylene.

<Means for solving the problems> That is, the present invention solves the problem by solving the general formula (1) R1: Hydrocarbon group having 1 to 10 carbon atoms R2: Hydrogen or hydrocarbon group having 1 to 10 carbon atoms n, m: An integer of 2 or more n/m: An ester group in the side chain having the structure shown by: 0.05 to 9 An object of the present invention is to provide a highly conductive polymer precursor having the following properties and a method for producing the same.

The present invention will be explained in detail below.

In the precursor of the present invention, R1 has 1 carbon number in the above formula (1).
-10 hydrocarbon groups, such as methyl, ethyl, propyl, isopropyl, n-butyl, 2-ethylhexyl, phenyl, cyclohexyl groups, etc., but hydrocarbon groups having 1 to 6 carbon atoms are preferred.

In the precursor of the present invention, in the above formula (1), R2 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 the method for synthesizing the polymer precursor of the present invention is not particularly limited, a method using a polymer sulfonium salt decomposition method described below is particularly preferred since it provides a highly conductive polymer.

The monomer used in the polymer sulfonium salt decomposition method has the general formula (2) 2,5-thienylene dimethylene bissulfonium salt represented by 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, and benzyl groups, but hydrocarbon groups having 1 to 6 carbon atoms, particularly 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,
A mixed solvent containing water and/or alcohol can also be used, but a solvent containing water is 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 bases. Ion exchange resins (OH type) and the like 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, first, the polymer precursor is a sulfonium salt, that is, 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, it is essential to add an organic acid ion corresponding to the above R ₁ COO ^- to the solvent used. 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) solvent used in polymerization or dialysis treatment to provide a precursor having a hydroxyl group or an alkoxy group as a side chain, thereby hindering the substitution reaction with an ester group. The alkoxy group substitution reaction inhibits the ester group substitution reaction more strongly than the hydroxyl group substitution reaction, so in order to efficiently perform the ester group substitution, it is preferable that the solvent contains water, and water or water/alcohol It is effective to use a mixed solvent, and the higher the water content, the more effective the 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
The ratio (A/B) of the sum of the signal intensities of and 4.5 ppm (B) and the sum of the signal intensities of 6.0 and 5.8 ppm (A) is 0.05 or more, which is effective for solubility and stability. ,
Since complete substitution is not industrial, the number is 9 or less, more preferably 0.1 to 4.

In order to obtain a polymer precursor that provides high conductivity, it is preferable that the molecular weight is sufficiently large, and at least n+m of the polymer precursor of general formula () is 4 or more,
Preferably 10 to 50000, e.g. molecular weight cutoff
Those having a molecular weight that cannot be dialyzed by dialysis treatment using a dialysis membrane 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; The object of the present invention is to provide a composition in which a molded article of any shape can be made from the solution, and in which poly-2,5-thienylenevinylene produced after the elimination reaction of the ester group exhibits high conductivity by 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 molding method is a method using a polymer precursor solution, which is then formed into a film by casting or into fibers by solution spinning, and a method in which the solution is applied to a 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 by dialysis treatment or reprecipitation treatment.

Poly-2,5-thienylenevinylene can be produced by removing the ester groups and hydroxyl groups and/or alkoxy groups that are side chains of the polymer precursor of the present invention. The side chain elimination treatment involves heat,
This can be carried out by applying conditions such as light and ultraviolet rays, but heat treatment is preferred. Further, it is preferable that the removal treatment of the side chain of the polymer precursor is performed 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. This can also be done in the medium.

When performing side chain elimination treatment by heat, heat treatment at too high a temperature will result in decomposition of the poly-2,5-thienylene vinylene produced, while at low temperatures the formation reaction is slow and impractical, so the normal treatment temperature is is 0
Temperatures between 50°C and 350°C are 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.

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 a high shear force, but high orientation can be imparted by heating and stretching a polymer precursor molded product from a polymer precursor solution.

<Effects of the Invention> As explained above, the novel polymer precursor of the present invention has high solubility and excellent shapeability, and poly-2,5-thienylene vinylene obtained from this precursor provides doped compositions with higher conductivity than conventional poly-2,5-thienylenevinylene, and the present invention also provides poly-2, 5-
A precursor of thienylene vinylene is provided.

<Example> The present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples. Example 1 2,5-thienylene-bis(methylenedimethylsphonium Bromide) 4.0g in 100ml of ion-exchanged water
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. 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 dimethylformamide. 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.

Reference example 1 Film obtained in 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 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.

Furthermore, 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 26 S/cm in 4 hours. The electrical conductivity was measured using the four-terminal method.

Comparative Example 1 4.0g of 2,5-thienylene-bis(methylenedimethylsphonium bromide) was added to 100ml of ion-exchanged water.
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 is converted into dimethylformamide.
30% dissolved. The resulting solution was cast and dried under a nitrogen stream to obtain a precursor film.

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 horizontal tube furnace at 200°C for 30 minutes in a nitrogen atmosphere to produce black poly-2,5-thienylene with metallic luster. A vinylene film was obtained.

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.

Example 2 After dissolving 4.0 g of 2,5-thienylene-bis(methylenedimethylsphonium bromide) in 100 ml of a mixed solvent of ion-exchanged water and methanol (volume ratio 1:1), 10 ml of 1N NaOH and methanol were dissolved.
30ml of the mixed solution was added dropwise at -30℃ over 30 minutes,
After the dropwise addition, stirring was continued for 1 hour at -30°C. This reaction solution was neutralized with HBr. Add 20% potassium acetate to this solution.
A solution prepared by dissolving 50 g of ion-exchanged water was added thereto, and the mixture was reacted with acetate ions 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.

Reference example 2 Film obtained in Example 2 (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. Furthermore, when this film was doped with iodine, which is an electron acceptor compound, from the gas phase at room temperature using a conventional method, it showed an electrical conductivity of 23 S/cm in 6 hours.

Comparative Example 2 After dissolving 7.8 g of 2,5-thienylene-bis(methylenedimethylsphonium bromide) in 200 ml of a mixed solvent of ion-exchanged water and methanol (volume ratio 1:1), 20 ml of 1N NaOH and methanol were dissolved.
80ml of the mixed solution was added dropwise over 30 minutes at -30℃,
After the dropwise addition, stirring was continued for 30 minutes at -30°C. This reaction solution is quickly passed through a dialysis membrane (cellotube, molecular weight fractionator).
8000 (manufactured by Union Carbide) and dialysis for one day by immersing it in a water-methanol mixed solvent (1:1) cooled to 0°C, a yellow precipitate was formed within the dialysis membrane. This precipitate was approximately 80% dissolved in dimethylformamide. The resulting solution was cast and dried under a nitrogen stream to obtain a precursor film.

On the other hand, the obtained precipitate was dissolved in deuterium-substituted dimethyl sulfoxide, and H-NMR showed proton signals near 4.8 ppm and 4.5 ppm, which are signals of methine groups at sites substituted with alkoxy groups or hydroxyl groups. However, 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.

Example 3 After dissolving 4.0 g of 2,5-thienylene-bis(methylenedimethylsphonium bromide) in 50 ml of a mixed solvent of ion-exchanged water and methanol, the solution was heated to -30°C.
It was cooled to Next, a strongly basic ion exchange resin (Amberlite IRA-401,
(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 filtrate was heated to 0°C, a solution of 20g of sodium n-butyrate dissolved in 50g of ion-exchanged water was added, and the temperature was raised 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. 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 830.

Reference Example 3 The polymer precursor film obtained in Example 3 was heated and stretched at up 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.

Then, when doping was performed with iodine according to a conventional method, the conductivity was found to be 1140 S/cm.

Claims (1)

[Claims] 1. General formula R1: Hydrocarbon group having 1 to 10 carbon atoms R2: Hydrogen or hydrocarbon group having 1 to 10 carbon atoms n, m: An integer of 2 or more n/m: Poly-2,5-thienylene represented by 0.05 to 9 vinylene precursor. 2 General formula R3, R4: Hydrocarbon group having 1 to 10 carbon atoms A-: A general formula characterized by polymerizing a sulfonium salt monomer represented by a counter ion with an alkali, and then reacting the polymer with organic acid ions. R1: Hydrocarbon group having 1 to 10 carbon atoms R2: Hydrogen or hydrocarbon group having 1 to 10 carbon atoms n, m: An integer of 2 or more n/m: Poly-2,5-thienylene represented by 0.05 to 9 Method for producing vinylene precursor.