WO2005100438A1

WO2005100438A1 - Method for producing polypyrrole film

Info

Publication number: WO2005100438A1
Application number: PCT/JP2005/005360
Authority: WO
Inventors: Tetsuji Zama; Susumu Hara
Original assignee: Eamex Corporation
Priority date: 2004-04-15
Filing date: 2005-03-24
Publication date: 2005-10-27
Also published as: JP2005298764A

Abstract

A method for producing a polypyrrole film using an electrolytic polymerization method, characterized in that an electrolyte solution used in the electrolytic polymerization method contains pyrrole or a pyrrole derivative as a monomer component, the above electrolytic polymerization method uses an electrolytic solution containing an aromatic ester as a solvent, the electrolytic solution contains a perchlorate ion, and a voltage is applied to a working electrode and a counter electrode, to thereby form an electroconductive polymer film on the working electrode.

Description

Specification

Method for producing polypyrrole film

Technical field

The present invention relates to a polypyrrole film containing perchlorate ions as a dopant, which can be greatly expanded and contracted by electrolytic oxidation and reduction.

Background art

[0002] It is known that conductive polymers such as polypyrrole exhibit electrolytic stretching, which is a phenomenon of stretching or deformation due to electrochemical redox. Electrolytic expansion and contraction of this conductive polymer is expected to be applied to applications such as micromachines, artificial muscles, artificial arms, artificial legs such as powered prostheses, and powered suits, because it generates forces such as pressure and tension during expansion and contraction. In recent years, it has attracted attention. As a method for producing such a conductive polymer, it is common to produce it by an electrolytic polymerization method. In the electrolytic polymerization method, usually, a monomer component such as pyrrole is added to an electrolytic solution, a working electrode and a counter electrode are set in the electrolytic solution, and a voltage is applied to both electrodes to increase the conductivity. A method of obtaining a molecular film on the working electrode is performed.

[0003] The conductive polymer obtained by the electropolymerization method was formed into a film with respect to the extension and generation force per 1 oxidation cycle as a conductive high molecule used in artificial muscle. It is known that when the expansion and contraction ratio of polypyrrole is 1%, a power of 3 MPa can be obtained. (For example, Non-Patent Document 1).

[0004] Non-Patent Document 1: Synthetic Metals, 90 (1997) 93-100 Disclosure of Invention

Problems to be solved by the invention

[0005] The above-described electrolytic polymerization method also corresponds to the above-described electrolytic polymerization method for obtaining a conductive polymer. In general, a supporting electrolyte is included in an electrolytic solution. As the supporting salt, a known electrolyte can be used.However, it has three advantages of being inexpensive, being electrochemically stable, and having good mixing properties in an electrolytic solution. It is desirable to use perchlorate ion (CIO-), which is a supporting salt that is advantageous in the production work. [0006] However, when the conductive polymer is used in an actuator such as a micromachine, an artificial muscle, or a prosthesis, the purpose is to make the actuator perform a large displacement movement. It is necessary to greatly improve the expansion and contraction rate of about 1%. The expansion and contraction ratio of the conductive polymer actuator containing perchlorate ion as a dopant was 3% or less.

[0007] In addition, polypyrrole films, which are conductive polymers, are generally insufficient in mechanical strength compared to general-purpose engineering plastic films, and are not suitable for applications such as electrodes in packages that do not require high mechanical strength. Although suitable, it cannot be suitably used for applications such as exterior films and flexible electrodes that require high mechanical strength. In particular, it is a conductive polymer containing perchlorate ion (CIO-) as a dopant.

Four

The conductive high molecular weight obtained by the electrolytic polymerization method using a solvent such as carbonate or butyl acetate has insufficient stretch ratio and mechanical strength per one oxidation reduction cycle.

[0008] An object of the present invention is to use perchlorate ion (CIO-), which is a supporting salt that is advantageous in the production operation.

Four

In addition, it is an object of the present invention to obtain a conductive polymer having a large expansion and contraction rate and a high mechanical strength. Means for solving the problem

[0009] The inventors of the present invention have conducted intensive studies and have found that the above-mentioned problems can be solved by using the method for producing a polypyrrole film of the present invention, thereby leading to the present invention. The present invention is as follows.

[0010] The present invention relates to a method for producing a polypyrrole film using an electrolytic polymerization method, wherein an electrolytic solution used in the electrolytic polymerization method contains pyrrole and / or a pyrrole derivative as a monomer component, and the electrolytic polymerization method is aromatic. An electrolyte containing an aliphatic ester as a solvent, wherein the electrolyte contains perchlorate ions, and a conductive polymer film is formed on the working electrode by applying a voltage to the working electrode and the counter electrode. This is a method for producing a polypyrrole film. In the above production method, perchlorate ion (CIO-) can be used as a supporting salt.

Four

Therefore, the manufacturing workability is good, and the obtained conductive polymer film has a large expansion and contraction ratio due to electrolytic expansion and contraction and high mechanical strength. In the present application, the polypyrrole film is not limited to a polypyrrole film that is a polymer containing pyrrole alone as a monomer component, but may be a pyrrole derivative, or a polymer containing pyrrole and a pyrrole derivative as monomer components. Including.

[ooii] Further, the present invention is a polypyrrole film comprising pyrrole and Z or a pyrrole derivative as a polymerized unit, wherein the polypyrrole film is a polypyrrole film obtained by an electrolytic polymerization method, wherein the electrolytic polymerization method is aromatic. A polypyrrole film using an electrolytic solution containing a group III ester as a solvent, wherein the electrolytic solution contains perchlorate ions.

[0012] The present invention is also an actuator element comprising at least a displacement part displaced by voltage application, an electrolyte and a counter electrode, wherein the displacement part is the above-mentioned polypyrrole film. The actuator is a perchlorate ion (CIO-) as a dopant.

4 Including and exhibiting a large expansion / contraction ratio per oxidation-reduction cycle and high mechanical strength, it can be suitably used as an actuator element. In particular, since the actuator element has high mechanical strength, it can be suitably used for a drive unit of a device that is subjected to a mechanical impact represented by a manipulator and a robot.

The invention's effect

[0013] As described above, in the method for producing a polypyrrole film of the present invention, since the obtained conductive polymer film has a large expansion and contraction rate due to electrolytic expansion and contraction, and high mechanical strength, the perchlorate ion (C1 o-) can be used as a supporting electrolyte, so that a large expansion and contraction rate and high mechanical strength

Four

A conductive polymer having a high degree of flexibility can be obtained more easily than a conventional production method. Further, the polypyrrole film of the present invention shows a large expansion / contraction rate per one oxidation-reduction cycle and has high mechanical strength, and thus is suitable as an actuator element, and is particularly subject to mechanical shock represented by a manipulator and a robot. It is more suitable as an actuator element used in the drive unit of the device.

BEST MODE FOR CARRYING OUT THE INVENTION

[0014] (Manufacturing method)

The present invention relates to a method for producing a polypyrrole film using an electrolytic polymerization method, wherein an electrolytic solution used in the electrolytic polymerization method contains pyrrole and / or a pyrrole derivative as a monomer component, and the electrolytic polymerization method contains an aromatic ester. A polypyrrole film comprising: an electrolytic solution containing a solvent; wherein the electrolytic solution contains perchlorate ions; and a conductive polymer film is formed on the working electrode by applying a voltage to the working electrode and the counter electrode. In the manufacturing method is there.

[0015] In the method for producing a polypyrrole film of the present invention, the electrolytic solution used in the electrolytic polymerization method contains pyrrole and Z or a pyrrole derivative as a monomer component, contains an aromatic ester as a solvent, and further contains perchlorate ions. Including.

The electrolytic solution contains perchlorate ions and contains an aromatic ester as a solvent, so that the workability of producing a polypyrrole film as a conductive polymer is easy, and the force is also reduced. It is possible to obtain a polypyrrole film having both a large expansion / contraction ratio per cycle and high mechanical properties. In the case where the electrolyte does not contain an aromatic ester as a solvent,

However, it is difficult to obtain a polypyrrole film having both a large expansion and contraction rate per one oxidation cycle and high mechanical properties.

The aromatic ester is not particularly limited as long as it has an aromatic ring and at least one ester bond in the molecule. The aromatic ester is, for example, an aromatic ester selected from the group consisting of methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, dimethyl phthalate, getyl phthalate, dibutyl phthalate, and methyl salicylate. Methyl benzoate and dimethyl phthalate are preferred because they can be used and the electrolyte has a high ionic conductivity. Although the reason is not clear, even when a salt containing perchlorate ion is used as the supporting salt, the interaction between polypyrrole chains is enhanced by using the aromatic ester as a solvent in the electrolytic solution, and a dense structure is obtained. Therefore, it is considered that a polypyrrole film having both a large expansion and contraction rate per redox vital and high mechanical properties can be obtained.

The aromatic ester is not particularly limited as long as it is contained as a solvent in the electrolytic solution, but is contained in the electrolytic solution at 60 to 90% by weight based on the total amount of the electrolytic solution. For example, it is possible to obtain a polypyrrole film having both a large expansion and contraction rate per oxidation reduction cycle and high mechanical properties.

[0019] In the method for producing a polypyrrole film of the present invention, the content of perchlorate in the electrolytic solution is particularly limited as long as it is stably dissolved in the electrolytic solution. Although not required, the electrolyte preferably contains 0.1 to 35% by weight, more preferably 1 to 20% by weight, in order to maintain good ionic conductivity. Perchloric acid The electrolytic solution containing the solvent can be obtained by dissolving perchlorate in the electrolytic solution. The perchlorate can be dissolved in the electrolytic solution, and is not particularly limited as long as there is little danger of explosion or the like. A force capable of using a tetraalkylammonium salt can be used. It is preferable to use butylammonium salt because it is easily available and has high solubility. By performing electrolytic polymerization using an electrolytic solution containing perchlorate ions, a polypyrrole film containing perchlorate ions as a dopant can be obtained.

In the method for producing a conductive polymer of the present invention, the working electrode in electrolytic polymerization is not particularly limited as long as it is an electrode that can be used in electrolytic polymerization. By using a nonmetallic electrode such as a metal electrode or an ITO glass electrode as the working electrode, a polypyrrole film having high mechanical properties can be obtained. The metal electrode is not particularly limited as long as it is an electrode mainly composed of a metal, but a metal of a metal element selected from the group consisting of Pt, Ti, Ni, Au, Ta, Mo, Cr and W A single electrode or an electrode of these alloys can be suitably used. It is particularly preferable that the metal species contained in the metal electrode is Ni or Ti because the conductive polymer obtained by the above-mentioned production method has a large expansion / contraction ratio and a large generating force and an electrode can be easily obtained. As the alloy, for example, trade names “INCOLOY alloy 825”, “INCONEL alloy 600”, and “INCONEL alloy X-750” (all manufactured by Daido Special Metal Co., Ltd.) can be used. In addition, a known electrode such as an ITO glass electrode can be used as the non-metal electrode. The polypropylene film obtained by using an ITO glass electrode as a working electrode in the electrolytic polymerization can exhibit a tensile strength of 60 MPa or more. The working electrode in the electrolytic polymerization is preferably a metal electrode from the viewpoint of mass productivity of the polypyrrole film.

In the method for producing a conductive polymer of the present invention, monomer components of the conductive polymer contained in the electrolytic solution used in the electrolytic polymerization method include pyrrole and Z, which are polymerized by electrolytic polymerization and exhibit conductivity. Alternatively, there is no particular limitation as long as it is a pyrrole derivative. The pyrrole derivative is not particularly limited as long as polypyrrole can be obtained by electrolytic polymerization. Use is made of, for example, 1-methylvirol, 1-phenylpyrrole, 3-methylpyrrol, 3,4-dimethylbilol, and 3-phenylpyrrole. be able to. Said mod As a nomer component, pyrrol is preferable because it is easy to produce and is stable as a conductive polymer. Also, two or more of the above monomers can be used in combination.

[0022] In the method for producing a conductive polymer according to the present invention, the electrolytic solution used in the electrolytic polymerization method contains a fluorine atom with respect to the organic compound solvent, the trifluoromethanesulfonic acid ion and Z or a central atom. A solution with a plurality of aions may contain a monomer of a conductive polymer, and may further contain other known additives such as polyethylene glycol and polyacrylamide.

As the electrolytic polymerization method used in the method for producing a conductive polymer according to the present invention, a known electrolytic polymerization method can be used as the electrolytic polymerization of a conductive high-molecular monomer. Either the constant current method or the electric sweep method can be used. For example, the electrolytic polymerization method can be performed at a current density of 0.01 to 20 mAZcm ² and a reaction temperature of −20 to 80 ° C. In order to obtain a conductive polymer having good film quality, the current density is 0.1 to 0.1 mAZcm ² . — 2mAZcm ² , reaction temperature of 10-40 ° C is preferable, and reaction temperature of 0-30 ° C is more preferable! / ,.

(Polypyrrole film)

The present invention is a polypyrrole film obtained by the above production method. That is, the present invention is a polypyrrole film comprising pyrrole and Z or a pyrrole derivative as a polymerized unit, wherein the polypyrrole film is a polypyrrole film obtained by an electrolytic polymerization method, and the electrolytic polymerization method comprises the steps of: A polypyrrole film, characterized in that the electrolyte solution contains perchlorate ions. Since the polypyrrole film is a polypyrrole film obtained by an electrolytic polymerization method containing perchlorate ions and an aromatic ester as a solvent in an electrolytic solution at the time of electrolytic polymerization, one polypyrrole film per oxidation cycle It can be obtained as a polypyrrole film having both high expansion and contraction and high mechanical properties.

[0025] The aromatic ester in the electrolytic solution of the electrolytic polymerization in the polypyrrole film of the present invention is the same as in the above production method. In other words, the aromatic ester is not particularly limited, but may be contained in the preferred electrolytic solution of methyl benzoate and dimethyl phthalate in an amount of 60 to 99% by weight based on the total amount of the electrolytic solution.

[0026] The perchlorate ion in the electrolytic solution of the electrolytic polymerization in the polypyrrole membrane of the present invention is as described above. It is the same as in the case of the manufacturing method. That is, the polypyrrole film preferably comprises 0.1 to 35% by weight of the electrolyte, more preferably 1 to 15% by weight.

[0027] The working electrode of the electrolytic polymerization in the polypyrrole film of the present invention is the same as in the above-mentioned production method. That is, it is possible to suitably use an electrode of a simple metal or an alloy of a metal element selected from the group consisting of Pt, Ti, Ni, Au, Ta, Mo, Cr and W.

[0028] The electrolytic polymerization method for the polypyrrole film of the present invention is the same as the above-mentioned production method, except for the aromatic ester, perchlorate ion, and other conditions except for the working electrode.

[0029] The polypyrrole film of the present invention is formed on a working electrode by an electrolytic polymerization method. The polypyrrole film formed on the working electrode peels off the working electrode force and is used for the actuator element.However, if the working electrode can be expanded and contracted, use the actuator element with the working electrode. You can also. The method of peeling the polypropylene film formed on the working electrode is not particularly limited, but it is immersed in a polar solvent such as acetone or propylene carbonate, and the attached electrolyte is washed, and then tweezers or the like are used. It can be peeled off using.

[0030] (actuator element)

The present invention is an actuator element including at least a displacement portion displaced by voltage application, an electrolyte, and a counter electrode, wherein the displacement portion is the above-mentioned polypyrrole film, and a voltage is applied to the polypyrrole film and the counter electrode. It is an actuator element to which a lead wire for supplying is connected. A polypyrrole film using pyrrole and Z or a pyrrole derivative as a polymerized unit as a displacement portion, wherein the polypyrrole film is a polypyrrole film obtained by an electrolytic polymerization method, and the electrolytic polymerization method uses an aromatic ester as a solvent. Since the electrolytic solution includes a polypyrrole film characterized in that the electrolytic solution contains perchlorate ions, the actuator element has a high mechanical strength with a tensile strength of 60 MPa or more. As the maximum expansion ratio due to electrolytic expansion and contraction, the expansion ratio can be 10% or more per 1 reduction. Since the actuator element has a high mechanical strength and a large expansion and contraction ratio, the mechanical impact represented by a manipulator and a robot Can be suitably used for a driving unit of a device provided with

[0031] The actuator element includes at least a displacement part displaced by applying a voltage, an electrolyte, and a counter electrode. The displacement part and the counter electrode can be installed so as to sandwich the electrolyte so that a voltage can be applied to each of the displacement part and the counter electrode. By disposing the displacement part and the counter electrode in this way, by applying a voltage to the displacement part and the counter electrode, the movement of ions is largely caused in the electrolyte between the displacement part and the counter electrode. Doping and undoping occur in the polypyrrole film. The doping and undoping of the polypyrrole film in the displacement portion allows the actuator element to move in a horse-like manner.

[0032] The electrolyte is not particularly limited as long as the polypyrrole film contains ions capable of performing doping and undoping. An electrolyte such as an electrolyte, a polymer electrolyte, or a gel electrolyte may be used as desired. Can be used. Further, an actuator element having a rod for accommodating the displacement portion, the electrolyte, and the counter electrode in a housing and taking out the displacement of the displacement portion to the outside can be provided. For example, when the electrolyte is an electrolyte, it is preferable to adopt an element configuration in which the displacement portion, the electrolyte, and the counter electrode are sealed in a housing. The method for applying a voltage to the displacement portion and the counter electrode is not particularly limited, and can be performed by a known method. For example, a voltage may be applied to the displacement portion and the counter electrode by connecting a lead wire to each of the displacement portion and the counter electrode, connecting the lead wire to a power source, and applying a voltage from the power source. it can.

[0033] The actuator element has a large expansion / contraction ratio per oxidation-reduction cycle in electrolytic expansion / contraction with high mechanical strength. Therefore, the drive unit of a device to which mechanical shock represented by a manipulator and a robot is applied is provided. It can be suitably used. Example

Hereinafter, Examples and Comparative Examples of the present invention will be described, but the present invention is not limited to the following.

(Example 1)

Known salts of the monomers and dopant ions described in Table 1 for the solvents described in Table 1 It was dissolved by a stirring method to prepare an electrolytic solution containing 0.25 mol Zl of a conductive polymer monomer and a concentration of perchlorate ion in Table 1. Using a titanium electrode (Ti electrode) as the working electrode and a platinum electrode (Pt electrode) as the counter electrode, electrolytic polymerization was carried out by the galvanostatic method with a polymerization current density of the value shown in Table 1. Was. By this electrolytic polymerization, the polypyrrole film of Example 1 having the conductivity and the film thickness shown in Table 1 was obtained.

(Examples 2 and 3)

A polypyrrole film was obtained in the same manner as in Example 1 except that the monomers, dopant ions, solvents, and working electrodes shown in Table 1 were used.

(Comparative Example 1)

A polypyrrole film of Comparative Example 1 was obtained in the same manner as in Example 1, except that the solvents shown in Table 1 were used as the solvent.

[0038] [Table 1]

TBAC 1 0 _4: perchlorate tetra - n-Petit Ruan monitor © beam

[0039] (Evaluation)

Working electrode force was also peeled off from the polypyrrole films of Examples 13 and Comparative Example 1 using acetone. Then, it was kept in an aqueous ImolZl PF solution (operating electrolyte) containing a working electrolyte (PF).

6 6

With respect to the retained polypyrrole film, the expansion / contraction ratio per redox vital was measured by the following measurement method. Further, the tensile strength of the polypyrrole films of Examples 13 and 13 and Comparative Example 1 was measured using the following measurement method. The results are shown in Table 1. The tensile strength was evaluated according to the following evaluation criteria.

[Method of measuring expansion / contraction ratio]

The film-shaped conductive polymer molded products obtained in Examples 13 and 13 and Comparative Example 1 were used as working electrodes having a length of 15 mm and a width of 2 mm, and a platinum plate was used as a counter electrode. The electrode is held in the electrolyte, connected to a power supply via a lead, and the potential (−0.9— + 0.7 V vs AgZAg +) is applied for one cycle to determine the displacement (displaced length). It was measured. The first oxidation-reduction process is performed by dividing the difference in displacement obtained by extending and contracting the working electrode by one cycle of application (one oxidation reduction cycle) by the original length of the working electrode. The expansion / contraction ratio per cycle, ie, one cycle of reduction of the acid, was determined.

(Method of measuring expansion ratio)

After cutting the polypropylene films obtained in Examples 13 and 13 and Comparative Example 1 into strips each having a length of 20 mm, the strips were subjected to aluminum tabbing so that the tab interval was about 4 mm, and the strips were cut into 5 mm width strips. Each test piece was prepared. Using each test piece, the tensile strength was measured at a test speed of 0.5 mmZmin using a known apparatus in accordance with the JIS K7127 film tensile test (strength). The tensile strength was measured using a tester “INSTRON5582”.

[0042] (Evaluation criteria)

〇: Tensile strength is equivalent to that of conventional general-purpose engineering plastics, excellent in tensile strength, and suitable for applications requiring high strength.

X: Tensile strength is comparable to that of conventional polypyrrole film, and is not suitable for applications requiring high strength.

[0043] (Result)

Example 13 The polypyrrole membrane of Example 13 has a stretching ratio per oxidation-reduction cycle of 11.2 to 13.5%, so the maximum value of stretching due to electrolytic stretching is 11.2% or more. The mechanical strength (tensile strength) was also 60.1 MPa or more. Therefore, the polypyrrole film of Example 13 uses an aromatic ester as a solvent at the time of electrolytic polymerization. The extensibility per reduction cycle was excellent and the mechanical strength was excellent.

On the other hand, although the polypyrrole film of Comparative Example 1 was formed by using a metal electrode, it was mechanically different from the polypyrrole film of Examples 13 to 13 because it did not use an aromatic ester as a solvent. Strength decreased.

Industrial applicability

[0045] In the method for producing a polypyrrole film of the present invention, since the electrolytic solution contains perchlorate ions, the polypyrrole production operability is reduced in the production of the polypyrrole film using the electrolytic solution containing another negative ion in the supporting electrolyte. Manufacturing workability is better than the method. Furthermore, the method for producing a polypyrrole film according to the present invention includes the step of reducing peroxidation due to electrochemical oxidation-reduction because the electrolyte contains perchlorate ions and the electrolyte further contains an aromatic ester. It is possible to obtain a polypyrrole film having a high mechanical strength and a large expansion / contraction ratio per cycle.

[0046] The polypyrrole film obtained by the above production method has a high mechanical strength with a large expansion ratio per one oxidation / reduction cycle in the expansion and contraction by electrochemical oxidation / reduction, and thus has a high mechanical strength. It can be suitably used. Further, the actuator element using the above-mentioned polypyrrole film as a dislocation portion has a large mechanical expansion ratio per one oxidation reduction cycle in the expansion and contraction by electrochemical oxidation-reduction, and thus has a high mechanical strength. It can be suitably used as an actuator element used in a drive unit of a device to which a mechanical shock is applied, such as a pulser and a robot.

Claims

The scope of the claims

[1] A method for producing a polypyrrole film using an electrolytic polymerization method,

The electrolytic solution used in the electrolytic polymerization method contains pyrrole and Z or a pyrrole derivative as a monomer component,

The electrolytic polymerization method uses an electrolytic solution containing an aromatic ester as a solvent,

The electrolyte contains perchlorate ions,

A conductive polymer film is formed on the working electrode by applying a voltage to the working electrode and the counter electrode.

A method for producing a polypyrrole film.

2. The method for producing a polypyrrole film according to claim 1, wherein the working electrode used in the electrolytic polymerization method is a metal electrode.

[3] The aromatic ester is selected from the group consisting of methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, dimethyl phthalate, getyl phthalate, dibutyl phthalate, and methylca salicylate. 2. The method for producing a polypyrrole film according to claim 1, wherein at least one is selected.

[4] The method for producing a polypyrrole film according to claim 1, wherein the electrolytic solution contains perchlorate ions at a concentration of 0.05-1. OmolZL.

[5] A polypyrrole film having a polymerization unit of pyrrole and Z or a pyrrole derivative, wherein the polypyrrole film is a polypyrrole film obtained by an electrolytic polymerization method,

A polypyrrole membrane, wherein the electrolyte contains perchlorate ions.

[6] The polypyrrole film according to claim 5, wherein the working electrode used in the electrolytic polymerization method is a metal electrode.

[7] The aromatic ester is selected from the group consisting of methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, dimethyl phthalate, getyl phthalate, dibutyl phthalate, and methyl salicylate. 6. The polypyrrole film according to claim 5, wherein at least one is selected.

[8] The polypyrrole film according to claim 5, having a tensile strength of 60 MPa or more.

[9] The polypyrrole film according to claim 5, wherein the polypyrrole film contains perchlorate ion as a dopant.

[10] An actuator element comprising at least a displacement part displaced by voltage application, an electrolyte, and a counter electrode, wherein the displacement part is the polypyrrole film according to claim 5.