JPH03122142A - Electrically conductive double structure polymer film and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject polymer film, having a structure of a cellular layer and noncellular layer and excellent mechanical characteristics and useful as material for positive poles, etc., by dissolving a pyrrole derivative together with an oxidizing agent in a mixed solvent under specific conditions, oxidatively polymerizing the pyrrole derivative and then forming a film. CONSTITUTION:The objective polymer film, obtained by dissolving (B) a pyrrole derivative and (C) an oxidizing agent in (A) a mixed solvent composed of (i) halogenated hydrocarbons and/or aromatic hydrocarbons, (ii) alcohols and/or halogenated alcohols and (iii) at least one selected from the group consisting of alkyl esters of lower fatty acids, dialkyl ethers and cycloalkyl ethers [at >=75/25 volume ratio of components (i + iii)/component (ii)], casting the resul tant solution onto a substrate having a flat surface, decompressing the atmo sphere under warming conditions and removing the component (A) and composed of the component (B) having a double structure in which a cellular layer is closely adhered to a noncellular layer.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a pyrrole-based conductive polymer membrane, and more specifically, a high strength membrane having a two-layer structure consisting of a porous layer and a non-porous layer. The present invention relates to a composite conductive polymer membrane and a method for manufacturing the same.

The composite conductive polymer membrane of the present invention not only has the electrical properties inherent to a pyrrole-based conductive polymer membrane, but also has mechanical properties due to its structure, particularly high tensile strength. It is expected to be used as a positive electrode material for electric double layer capacitors, etc.

All of them are porous membranes, and porous membranes have been considered preferable from the viewpoint of electrical properties.

[Problem that the invention seeks to solve]

Since conventional pyrrole-based conductive polymer films are porous films, they are generally extremely brittle and do not have self-retention properties. Therefore, when using them as electrodes, etc., it is necessary to form a film on a current collector in advance. It was necessary.

On the other hand, the pyrrole-based conductive film disclosed by the present applicant is a self-retaining film with relatively high strength. membrane is required.

(Prior art) There are many reports on pyrrole-based conductive polymer membranes, and the applicant has also proposed a conductive polymer membrane using a 3.4-position asymmetric pyrrole derivative as a raw material (International Publication WO 37100843G). (see specification).

The object of the present invention is to provide a composite conductive film made only of a pyrrole derivative polymer having high strength and a method for producing the same.

[Means for solving problems]

As a result of intensive research to achieve the above object, the present inventors have discovered that by dissolving a pyrrole derivative together with an oxidizing agent in a mixed solvent under specific conditions and oxidatively polymerizing it to form a film, a porous layer and a non-porous layer can be formed. The present invention was completed based on the discovery that a composite membrane having a two-layer structure consisting of two layers can be obtained.

It is a composite membrane consisting only of a polymer of a 3-, 4-position asymmetric pyrrole derivative represented by (See drawings) The present invention is a composite conductive polymer membrane characterized by comprising a polymer membrane of a pyrrole derivative having a two-layer structure in which a porous layer and a non-porous Ijt layer are in close contact with each other.

In the present invention, the composite conductive polymer membrane has the following general formula (
1) (Here, R1 and RZ represent hydrogen, an optionally substituted alkyl group, an optionally substituted benzyl group, or an optionally substituted phenyl group, and may be the same (or different) Examples of the pyrrole derivative represented by the general formula (1) include 4-methylpyrrole-3-carboxylic acid, 4-phenylpyrrole-3-carboxylic acid, methyl 4-methylpyrrole-3-carboxylate,
Ethyl 4-methylpyrrole-3-carboxylate, 4-〇-
Methyl propylpyrrole-3-carboxylate, ethyl 4-n-propylpyrrole-3-carboxylate, pyrrole-3
-carboxylic acid, hexyl 4-methylpyrrole-3-carboxylate, methyl 4-benzylpyrrole-3-carboxylate, dodecyl 4-methylpyrrole-3-carboxylate, stearyl pyrrole-3carboxylate, 4-phenylpyrrole 3- Stearyl carboxylate, 4-methylpyrrole-3-
Examples include phenyl carboxylate, benzyl 4-methylpyrrole-3-carboxylate, and the like, and the composite membrane is a homopolymer membrane or a copolymer membrane of two or more of these.

The composite conductive polymer film is prepared by dissolving at least one of the pyrrole derivatives and an oxidizing agent in a mixed solvent, casting the solution onto a substrate with a flat surface, heating or reducing the pressure without heating, and dissolving the solvent in the solvent. It can be manufactured by removing.

As an oxidizing agent, FeC1z, FQCl, 6HzO1F
(1(N OzL, F e (N Oi) * ' x
H2O, etc., and 1 to 1 mole of pyrrole derivative
10 moles are used, preferably 1 to 4 moles.

The mixed solvent consists of the following A, B and C, (A+
C) A mixed solvent with a ratio of /B≧75/25 (volume ratio) is used.

A: Halogenated hydrocarbons and/or aromatic hydrocarbons B: Alcohols and/or halogenated alcohols C: At least one type A selected from the group consisting of lower fatty acid alkyl esters, dialkyl ethers, and cycloalkyl ethers As the halogenated hydrocarbons, for example, 12-dichloroethane, l
, 2-dibromoethane, 1,1,2-1-dichloroethane, Ll, 1-)lichloroethane, etc., as well as aromatic hydrocarbons, have a boiling point of 30 to 150 at normal pressure.
C. non-W-substituted or alkyl-substituted compounds, such as benzene, toluene, xylene, etc., are used singly or as a mixture of two or more.

Alcohols in B include methanol, ethanol, isopropanol, butanol, etc., and halogenated alcohols include 1,1゛-dichloroethanol, 2.2''-
Dichloroethanol, ethylene chlorohydrin, 3-bromopropanol, etc. are used singly or as a mixture of two or more.

As the lower fatty acid alkyl ester of C, ethyl acetate,
Butyl acetate, ethyl propionate, etc., as dialkyl ethers, diethyl ether, di-n-butyl ether, diisopropyl ether, etc., as cycloalkyl ethers, dioxane, tetrahydrofuran, etc., singly or as a mixture of two or more used.

The mixing ratio of each of the above-mentioned solvents varies depending on the type and mixing ratio of the pyrrole derivative and oxidizing agent used, but it is determined as appropriate so that the volume ratio is within the range of (A+C)/B≧75/25 and that the whole is uniformly dissolved. selected.

As a substrate with a smooth surface, a glass plate, a Teflon plate, a resin plate, a metal plate, a Teflon-coated metal plate, etc., which are resistant to corrosion by solvents, oxidizing agents, etc., are used.

A solution prepared by dissolving a pyrrole derivative and an oxidizing agent in the mixed solvent is cast onto this substrate, and the solvent is removed by heating or reducing the pressure without heating.

The temperature is 10-100°C, preferably 30-50°C.

On the other hand, the pressure is reduced from normal pressure to 100 torr or less, preferably 5 Q torr or less, in 10 to 30 minutes, and the pressure is further maintained at that reduced pressure for 10 to 60 minutes.

By employing the above film forming method, the composite conductive polymer film of the present invention can be easily obtained.

[For production]

As shown in the electron micrograph of the attached drawing, the composite conductive polymer membrane of the present invention has a two-layer structure in which a porous layer and a non-porous layer do not show clear boundaries.

That is, the porous layer and the non-porous layer are assumed to be chemically continuous.

Furthermore, the non-porous layer not only has the electrical properties of a pyrrole derivative polymer itself, but also imparts excellent mechanical properties, particularly strength, to the polymer membrane.

On the other hand, porous layers provide excellent electrical properties as described above.

Therefore, the composite conductive film of the present invention not only exhibits excellent electrical properties due to these synergistic effects, but also exhibits extremely excellent mechanical properties, especially tensile strength and flexibility, even in secondary processing. With a conductive film possible.

Ru.

The method for producing a composite conductive polymer membrane of the present invention is characterized by using a mixed solvent at a specific mixing ratio and by removing the solvent under reduced pressure.

That is, in the process of removing the mixed solvent, there are differences in the evaporation rate of each solvent component, and the association MB of the pyrrole derivative and/or its polymer with the residual solvent is different, so that the composite membrane is obtained. However, the mechanism is not clear.

Under the conditions of using the above-mentioned solvent alone, a mixture of two solvents, or an excess of solvent B, only a relatively brittle porous or non-porous membrane can be obtained, or the membrane itself cannot be obtained. .

〔Example〕

The present invention will be explained in more detail with reference to Examples and Comparative Examples.

However, the scope of the present invention is not limited in any way by the following examples.

(1) Production of conductive polymer membrane In a nitrogen atmosphere, the oxidizing agent F is added to a mixed solvent consisting of dried ethyl acetate, dichloroethane, and methanol.
eCj! , and filtered under nitrogen atmosphere to remove solids to obtain a homogeneous oxidant solution. 3 to 5 ml of this solution
A raw material solution was prepared by dissolving 0.3 g of benzyl -methylpyrrole-4carboxylate.

The prepared raw material solution was cast onto a glass substrate placed on a hot plate heated to 40 to 50°C with a hood, the pressure was reduced to 60 torr for 15 minutes, and the pressure was further maintained at 60 torr for 15 minutes to remove the solvent. After removing the
A conductive polymer membrane was produced by washing with methanol and then acetone and drying.

(2) Characteristics of conductive polymer film The following characteristics were measured for the conductive polymer film obtained in item (1) above.

(al Observation of the surface and cross section using a scanning electron microscope, and the film thickness μm) and the pore diameter of the porous layer (μm)
m) Mountain) Conductivity (S/am) in the cross-sectional direction (σ) when doped with iodine and in the surface direction (σ) of the porous layer and the non-porous layer The following method was used for measurement.

Cross-sectional direction: A thin gold film is deposited on both sides, and calculated from the voltage between both sides when a constant voltage is applied. Surface direction: Measured by the four-terminal method using a surface resistor (cl) Charge-discharge capacity obtained by cyclic portamometry ( mc/mg) (C1 tensile strength (Kg/c+d) Measured according to the vulcanized rubber test method using a test piece: No. 3 dumbbell and a crosshead speed of 300 mm/min. The measurement results are shown in Table 1 and obtained in Example 1. Scanning electron micrographs of the cross section of the composite conductive polymer membrane and the surface of the porous layer are shown in the attached FIGS. 1 and 2.

As shown in Table 1, the composite conductive polymer membrane of the present invention has the electrical properties (charge/discharge characteristics) inherent to a virol-based conductive polymer membrane, and has excellent mechanical properties (tensile strength and ).

big.

〔Effect of the invention〕

As described above, the present invention is a novel composite conductive polymer membrane consisting of a two-layer structure consisting of a porous layer and a specific porous layer consisting only of a pyrrole derivative polymer, and from its structural characteristics: It has extremely excellent mechanical properties.

Therefore, since the composite conductive polymer membrane of the present invention can be subjected to secondary processing and has flexibility, it can be used as a positive electrode material, especially in paper-type secondary batteries, electric double layer capacitors, etc. be able to.

[Brief explanation of drawings]

Figure 1 Scanning electron micrograph (1,200x) of the cross-sectional structure of the composite polymer membrane obtained in Example 1 Figure 2 Surface of the porous layer of the composite polymer membrane obtained in Example 1 Scanning electron micrograph (1,000x) of the shape of

Claims (3)

[Claims] (1) A composite conductive polymer membrane comprising a pyrrole derivative polymer membrane having a two-layer structure in which a porous layer and a non-porous layer are in close contact with each other. (2) In claim (1), the pyrrole derivative is
The following general formula [I] ▲Mathematical formulas, chemical formulas, tables, etc.▼[I] (Here, R^1 and R^2 are hydrogen, an optionally substituted alkyl group, and an optionally substituted benzyl group. 3, which represents a group or an optionally substituted phenyl group, and may be the same or different from each other.
Composite conductive polymer membrane characterized by being a 4-position asymmetric pyrrole derivative (3) A: halogenated hydrocarbons and/or aromatic hydrocarbons B: alcohols and/or halogenated alcohols C: at least one selected from the group consisting of lower fatty acid alkyl esters, dialkyl ethers, and cycloalkyl ethers Type 1 consisting of the following A, B and C, (A+C)/B≧75/
Claim No. 2, characterized in that the pyrrole derivative and the oxidizing agent are dissolved in a mixed solvent of 25 (volume ratio), cast onto a substrate having a flat surface, and the solvent is removed under reduced pressure while heating. Method for producing a composite conductive polymer membrane according to item 1) or item (2)