JPS6336940B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a conductive polymer film. More specifically, the present invention relates to a polythiophene composite film in which a conductive layer made of a thin film of metal or metal oxide is interposed between a substrate made of plastic film.

[Prior art]

Conventionally, a transparent conductive film in which plastic is coated with isodium oxide as a metal oxide has been described, for example, in US Pat. No. 2,932,590.
Also, for example, G. Tourillon and F. Garnier:
J. Electroanal. Chem., 135 (1982) 173-178, conductive polymers such as polypyrrole, polythiophene, polyfuran, etc. are deposited on metals such as platinum, gold, or metal oxides such as tin oxide, indium oxide, etc. has been described to be formed electrochemically.

These conductive polymers, which have extremely high conductivity and whose value can be controlled arbitrarily by doping, are used not only as new conductive materials, but also in applications such as solar cells, rechargeable secondary batteries, and optoelectronic devices. Polythiophenes are attracting attention from the viewpoint of various applications, and polythiophenes are particularly attracting attention from the viewpoint of stability of performance. (Example: G, Tourillon
and F, Garnier; J, Electrochem.Soc:
Electrochemical Science and Technology
Vol.130, No.10 October1983, p.2042−2044). As a method for polymerizing conductive polymers, electrolytic polymerization is particularly important because it allows films of arbitrary thickness to be obtained. (Example: Kaneto, Yoshino; Functional materials
(April 1984 issue, p. 8) As a proposal that seems to be related to these findings, for example, a conductive polymer obtained using a metal oxide as an anode can be easily peeled off from the anode, so it can be formed into a film without being damaged. A conductive or semiconductive polymer composition can be obtained (Japanese Patent Application Laid-open No. 196232/1983), or
A conductive or semiconductive polymer composition electrolytically oxidized with a thin film metal or metal oxide semiconductor anode supported on a substrate made of a resin composition or glass,
There are reports that it is easy to peel off from the anode, and that it can be obtained with any shape or area, and in particular, it is easy to obtain one with a large area (Japanese Patent Laid-Open No. 58-213027).
All of these are for use alone by peeling a conductive polymer from an anode in the form of a film.

However, when using a conductive polymer film alone, for example, it can be used for rechargeable and dischargeable secondary batteries,
In particular, when used as a material for an assembled battery type, there are usage problems such as the need to combine it with materials that make up the insulating layer to prevent internal short circuits in the battery, and when using a conductive polymer film alone.
There are disadvantages such as the need to use a film that is thicker than required for functionality due to lack of mechanical strength, and when used as a material for optoelectronic elements, glass must be used as a support, resulting in poor flexibility. It had problems and drawbacks such as lack of quality and easy breakage.

In connection with the process for producing a film-like polymer of pyrrole, it is also possible, but unnecessary, to separate the precipitated film-like polymer (of pyrrole) from the anode active material. The method of operation using the anode active material in the form of a finite belt is desirable, especially when the resulting polymer film is to remain on the anode active material at all times.
23889), but to date, polythiophene, which exhibits more stable quality as an industrial material and requires a much higher applied voltage than polypyrrole in electrolytic polymerization, has been produced only as a conductive polymer film, or as an industrial material. have only been used with supports such as glass plates, and their problems and drawbacks remained unresolved.

[Purpose of the invention]

The present invention was developed as a result of research aimed at solving the drawbacks and problems that conventionally existed when a conductive polymer made of polythiophene was used as a support using a single film or glass. We found that all of these problems could be solved by using a film and using polythiophene as an integral part of the non-conductive plastic film that serves as the base, without peeling it off. Based on this, various studies have been carried out and the present invention has been completed.

The polythiophene composite film according to the present invention in which a thin conductive layer made of a metal or metal oxide is interposed between a base made of a non-conductive plastic film can provide a conductive polymer film of any shape and area. Of course, it also offers advantages not found in conventional conductive polymer membranes alone, such as toughness, flexibility, and ease of handling due to being integrated with plastic film. In addition, by using a non-conductive plastic film as a base material with excellent chemical resistance against organic solvents, acids, alkalis, etc., it can be used as a material for rechargeable and dischargeable secondary batteries, for example, and has both the functions of an insulating layer and a support. Moreover, by selecting a transparent non-conductive plastic film, a support such as glass is not required, and for example, K. Yoshinoet, al.; Japanese Journal of
applied Physics Vol.22, No.．． 3, march1983pp
This provides a material suitable for electronic devices such as the optoelectronic elements proposed in L157-L158.

[Structure of the invention]

The present invention comprises a substrate consisting of a non-conductive plastic film of polyetheretherketone, polyethersulfone, polyetherimide, polysulfone or polyphenylene sulfide; a thin conductive intermediate layer consisting of a metal or metal oxide; This is a polythiophene composite film characterized by having a surface layer made of a thin film of polythiophene or a derivative thereof.

The non-conductive plastic film used in the present invention can be obtained by conventional extrusion molding, calendar molding or cast molding. These films can be used either with a treatment to strengthen the bond with a thin conductive layer of metal or metal oxide, or without any such treatment. It will be done.

Polythiophene is much more stable in air than other conductive polymers such as polyacetylene and polypyrrole, so it is not only expected to be a new conductive material, but also when it is doped or dedoped with impurities. Various applications are expected using the functions shown below. For example, by doping and dedoping polythiophene electrochemically, it is being used as a material for rechargeable and dischargeable secondary batteries and optoelectronic devices. As described above, when polythiophene is used as an active material in a redox reaction, chemical resistance to organic solvents, acids, alkalis, etc. is an essential condition.

Conventionally, it has been known to form a conductive polymer film by electrolytic oxidation on a polyester film coated with indium oxide or the like in the form of a thin film. However, polyester film does not have sufficient chemical resistance and lacks reliability in terms of performance when used as an active material for redox reactions in the form of an integral part of a conductive polymer.

In the present invention, polyetheretherketone (PEEK), polyethersulfone (PES), polyetherimide (PEI), polysulfone (PSF) and polyphenylene sulfate are used as non-conductive plastic films with sufficiently high chemical resistance. By focusing on polythiophene (PPS), etc., and using these non-conductive plastic films as a substrate, we have created a polythiophene composite film suitable for use as an active material in redox reactions while taking advantage of the excellent performance of polythiophene for the first time. This is what was obtained.

PEEK and its derivatives used in the present invention or
The film of PPS and its derivatives is preferably a stretched film.

Examples of the metal or metal oxide used in the present invention include, but are not limited to, the following substances.

Metals: gold, platinum, palladium, rhodium, nickel, and alloys based on these.

Metal oxides: tin oxide, indium oxide, zinc oxide, vanadium pentoxide and ITO (indium oxide)
Substances that contain impurities in these compounds, such as teine oxide).

If transparency is required, tin oxide, indium oxide, ITO, etc. are preferable.

Methods for forming these metals or metal oxides on plastic films include vacuum evaporation,
General thin film formation techniques such as sputtering, ion plating, and plasma CVD can be used.

PEEK, PES, PEI, especially used in the present invention
Plastic films such as PSF and PPS have high heat resistance, so when forming these metals or metal oxides, it is possible to perform treatments such as heating the substrate, and it is possible to form a firmly fixed metal or metal oxide layer on the plastic film. Obtainable. In contrast, general-purpose plastics such as polyethylene, polypropylene, or polystyrene have poor heat resistance and are difficult to form into strong metal or metal oxide thin films. Furthermore, although fluororesin films generally have excellent chemical resistance, they are difficult to form metal oxides such as ITO films.

In the present invention, polythiophene or a derivative thereof is formed by interposing a thin film of a metal or metal oxide between a non-conductive plastic film and is integrated with these materials to form a conductive polymer film. For example, "Functional Materials" April 1984 issue p8-
It is synthesized from the following compounds by the electrolytic polymerization method known in 18, but is not limited to this, and also exists in the polythiophene synthesized as an additive and forms a part of the polythiophene. This term also includes dopants that

Thiophene, 3-methylthiophene, 3,4-
dimethylthiophene, 3-bromothiophene,
3,4-dibromothiophene, 2,2'-bithiophene.

〔Effect of the invention〕

The polythiophene composite film according to the present invention is
Since it is used in combination with non-conductive plastic film, it has enhanced toughness against environmental changes by utilizing the excellent physical properties of plastic film, such as heat resistance, cold resistance, and mechanical properties. As a result, polythiophene can be used at the minimum thickness necessary for functionality, even in thin films that would be difficult to handle with conventional polythiophene alone. By selecting a plastic film, it is suitable as a material for optoelectronic elements of any shape and area, which does not require a support such as glass, is safer against breakage, is lightweight, and has an arbitrary shape and area. Furthermore, by using a non-conductive plastic film with excellent chemical resistance as a base, for example,
It is also suitable as a material that can be used as a material for chargeable and dischargeable secondary batteries and electronic devices, and as a redox reaction active material that has both the functions of an insulating layer and a support.

〔Example〕

(1) LiBF ₄ (0.2 mol/) and thiophene monomer (0.2 mol/) were dissolved in acetonitrile to make an electrolyte, and a PEEK conductive film on which ITO had been deposited in advance was inserted as an electrode, and a nickel plate was inserted as a counter electrode. When a voltage of 10 V was applied so that the PEEK conductive film acted as an anode, a current of about 8 mA/cm ² flowed, and a good composite film of PEEK/ITO film/polythiophene was obtained. The conductivity of the polythiophene layer immediately after polymerization using the four-probe method is:
It was about 30S/cm.

(2) NaPF ₆ (0.2 mol/) and thiophene monomer (0.2 mol/) are dissolved in benzonitrile to form an electrolyte, which is then used as an electrode to face a polyphenylene sulfide (PPS) conductive film plated with nickel in advance. Insert a nickel plate as an electrode, so that the PPS conductive film becomes the anode.
When a voltage of 20 V was applied, a current of about 20 mA/cm ² flowed, and a good composite film of PCTFE/nickel layer/polythiophene was obtained. The conductivity of polythiophene immediately after polymerization by the four-probe method is approximately
It was 100S/cm.

(3) LiBE ₄ (0.2 mol/) Thiophene monomer (0.2 mol/) is dissolved in benzonitrile as an electrolyte, and ITO is added as an electrode in advance.
A nickel plate is inserted as a counter electrode to a polyether sulfon (PES) conductive film deposited with
When a voltage of 20V is applied so that the PES conductive film acts as an anode, a current of approximately 15 mA/cm ² flows, and at the point when approximately 0.3 coulombs of this flow, a blue polythiophene with a thickness of approximately 1 μm and a PES conductive film A composite film consisting of membranes was obtained. After the formation, the polythiophene layer turned red when dedoped by applying a voltage of opposite polarity. FIG. 1 shows changes in the light absorption spectrum due to doping and dedoping of this thin film.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the optical characteristics of a polythiophene composite film obtained according to the present invention. 1 is polythiophene in an undoped state, and 2 is polythiophene in a doped state.

Claims (1)

[Claims] 1. A substrate made of a non-conductive plastic film of polyetheretherketone, polyethersulfone, polyetherimide, polysulfone or polyphenylene sulfide, a thin conductive intermediate layer made of metal or metal oxide, and polythiophene or its like. A polythiophene composite film having a surface layer made of a thin film of a derivative.