JPH0279499A - Chemical doping method for high molecular film - Google Patents

Abstract

PURPOSE:To make it possible to control a form by controlling evenly stable solution including an aromatic compound, oxidant, solvent, applicating it onto a substrate, thereafter forming a conductive high molecular film after vaporization-removing the same, washing it with a solvent so as to have a neutral film, and further immersing it in a salt solution. CONSTITUTION:An aromatic compound represented by such as pirol, thiophen or anylin group is added to an oxidant and solvent, and an even mixture solution without deposition of polymer is merely cast, so that high molecular films excellent in their conductivity and film strength are formed. These polymer films are washed by an organic solvent to remove excessive oxidant and soluble low grade polymer, thus obtaining a neutral film. Further, this film is doped easily by being dipped in a salt solution having various anions as anti-ions, whereby it is turned into the form of conductive high molecular. By selecting functional radicals having photosensitivity, electorosensitivity and the like, the conductive high molecular having such function can be obtained easily.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for chemically doping conductive polymers, and is particularly suitable as an electromagnetic shielding material, an antistatic material, and a material for other electrochemical devices. This invention relates to a method for doping conductive polymers.

[Conventional technology]

Polymers such as pyrroles and thiophenes are characteristic polymers that have a conductivity ranging from an insulator with a conductivity of about 10'S/cI to about 10'S/cm by performing a doping treatment. Therefore, these conductive polymers can be used in a wide range of applications utilizing their conductivity and doping mechanism, and many studies have been conducted on them.

As a method for obtaining conductive polymers, (1) an electrolytic oxidative polymerization method is known in which a monomer is oxidatively electrolyzed in a solution containing various electrolytes to deposit a polymer on an anode. Since the polymer deposited on the electrode has an oxidation potential lower than that of the monomer, it is further oxidized on the electrode, becomes a radical cation, forms a salt with the electrolyte anion, and is obtained as a doped (oxidized state) conductor. By using salts with different electrolyte anions, polymers doped with various anions can be obtained. Conductive polymers have been functionalized using such methods, and their application to EC materials and the like has been reported.

Furthermore, it is also possible to obtain the polymer as a salt such as Cl-1Cnatsu04-1BFa- and convert it into other anions by electrochemical methods.

However, the above method is complicated because it requires an electrolytic cell, and the shape of the polymer is limited depending on the shape of the electrode to be electrodeposited, making it difficult to control the shape unique to the polymer.

(2) On the other hand, a chemical oxidation method using an oxidizing agent to polymerize in a solvent or without a solvent is also well known. In this method, the resulting polymer is doped with the oxidizing agent or its by-products and generally has electrical conductivity. It is relatively difficult to convert with various anions as mentioned above.

[Problem to be solved by the invention]

The present invention may provide a method for chemically doping polymeric films that is easy to control shape.

[Means to solve the problem]

The present inventors first added aromatic compounds represented by pyrroles, thiophenes, and anilines to an oxidizing agent and a solvent,
We have discovered a method for producing a polymer film with excellent conductivity and film strength by simply casting a uniform mixed solution that does not show polymer precipitation (PCT/JPNS100
It has been found that by washing these polymer films with an organic solvent to remove excess oxidizing agents and soluble low polymers, a neutral a (undoped state) film can be obtained. Furthermore, it was found that simply by immersing this membrane in a salt solution containing various anions as counterions, it could be easily doped and become a conductive polymer. That is, the present invention prepares a homogeneous and stable solution containing an aromatic compound, an oxidizing agent, and a solvent, transfers the solution to a Go board, and then evaporates and removes the solvent to produce a conductive polymer film. , is a method for chemical doping of polymer films, which comprises washing the polymer film with a solvent to make it a neutral film, and then immersing it in a salt solution.

The method for producing the above-mentioned conductive polymer film (hereinafter referred to as the cast film formation method) has already been published in PCT/JP88100764.
This film-forming method was applied for in 2011, and its gist will be explained below.

(+) Aromatic compounds (pyrrole and its derivatives) Pyrrole, pyrrole dimer, 3,3゛-dimethyl-2
, 2'-bipyrrole 4.4'-dicarboxylic acid distearyl, 3.3'-dimethyl-2゜2゛-bipyrrole-4,
4”-dihexyl dicarboxylate, 4-methylpyrrole-
3-carboxylic acid, 4-phenylpyrrole-3-carboxylic acid, methyl 4-methylpyrrole-3-carboxylate, 4-
Ethyl methyl pyrrole-3-carboxylate, methyl 4-n-propyl pyrrole-3-carboxylate, ethyl 4-n-propyl pyrrole-3-carboxylate, methyl pyrrole-3-carboxylate, 3-methyl pyrrole, 3- xylpyrrole, pyrrole-3-carboxylic acid, hexyl 4-methylpyrrole-73-carboxylate, methyl 4-benzylpyrrole-3-carboxylate, dodecyl 4-methylpyrrole-3-carboxylate, stearyl pyrrole-3-carboxylate, Stearyl 4-phenylpyrrole-3-carboxylate, 3-phenylpyrrole, 3-acetopyrrole, 3-undecylcarbonylpyrrole, 3-aminomethyl-4-
Methylpyrrole, 3-amizmedel-4-phenylpyrrole, 3-acetaminomethyl-4-phenylpyrrole, 3-peishylpyrrole, 3-methyl-4-dimethylaminocarbamoylpyrrole, 3-methyl-4-dimethylaminotylpyrrole , phenyl 4-methylpyrrole-3-carboxylate, benzyl 4-methylpyrrole-3-carboxylate, 4-methylpyrrole-3-carboxylic acid (4-
phenylazophenyl), 4-methylpyrrole-3-carboxylic acid (16-bromo-2,3°5.6,8,9,1
1.12-octahydro-1,4°7,10.13-benzopentaoxacyclopentadecin-15-yl)methyl, etc.

In particular, - at the 3 or 4 position of alkyl pyrrole-3-carboxylate, alkyl 4-methylpyrrole-3-carboxylate, alkyl 4-benzylpyrrole-3-carboxylate, etc.
A 3- and 4-position asymmetrically substituted pyrrole derivative having a COOR group (wherein R represents an alkyl group, benzyl group, or phenyl group) is preferred.

(Thiophene and derivatives thereof) Alkyl t such as thiophene, 3-methylthiophene, 3.4-dimethylthiophene, 3-hexylthiophene, and 3-stearylthiophene Halogen z such as IAthiophene and 3-bromothiophene? A thiophene, 3
-polyether-substituted alkylthiophene such as methoxydiethoshimethylthiophene, 3-phenylthiophene, 3-benzylthiophene, 3
-Methyl-4-phenylthiophene, 2,3゜-bithiophene, 2.2゛-bithiophene, 2.2'2゛.

In particular, thiophenes substituted with C4 or higher alkyl, such as -thylthiophene, are preferred.

(Aromatic amines and derivatives thereof) Aniline, N-monosubstituted aniline (substituents include alkyl, phenyl, p-aminophenyl, N-monoalkylaminophenyl, N-monophenylaminophenyl,
N-monophenylamino diphenyl, etc.), substituted aniline [substituents include 〇-amino, m-amino, p-(p-
aminophenoxy), p-(p-aminophenyl), etc.]
, naphthylamine, perylene, and the like, and these aromatic amines may have a substituent on the benzene ring, and unsubstituted aniline is particularly preferred.

(Others) These include benzene, diphenyl, naphthalene, anthracene, azulene, carbazole, benzothiophene, etc., and these may have a substituent.

The above aromatic compounds can also be used as a mixture of the same or different types.

(2) Oxidizing agent FeC11, CuCIt, Fe(NO3)3.5bC1
,, MoCl5 etc. or their hydrates or mixtures thereof, especially pec++, FeCl5.6H20, Fe
(NOs)i ・9H! 0 is preferred. The amount used is preferably 1 to 10 mol, particularly 1 to 4 mol, per 1 mol of the aromatic compound.

(3) Solvent diethyl ether, diisobutyl ether, di-n-
7' Aliphatic ethers such as thyl ether, diisopropyl ether and dimethoxyethane, cyclic ethers such as THF and dioxane, alcohols such as methanol, ethanol and isopropyl alcohol R1 Halogenated hydrocarbons such as methylene chloride and chloroform, benzene and toluene , aromatic hydrocarbons such as xylene, aliphatic hydrocarbons such as hexane and heptane, alicyclic hydrocarbons such as cyclohexane, esters such as ethyl acetate and butyl acetate, acetone,
Aliphatic and alicyclic ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, nitroalkanes such as nitromethane, etc., or mixed solvents thereof, particularly diethyl ether, methanol, THF, etc., and mixed solvents thereof are preferably used. The amount is preferably 50 times the amount required to dissolve the oxidizing agent to form a homogeneous solution, and particularly preferably 10 to 30 times the amount.

Specific examples of the base material to which the precursor solution of the polymeric substance is applied in the present invention will be given below. Surfaces of glass plates, metal plates, polymer films, ceramic plates, glass plates coated with conductive films, fibers, wires, rods, pipes, etc. should be pretreated with a silane cuff pulling agent. You can also administer it.

As a method for applying the precursor solution to the substrate by spraying, a casting method, a dipping method, a spray method, an ultrasonic atomization method, a spin coating method, etc. are employed.

Six tricks: As a method for removing the solvent, the base material coated with the solution is heated to about 0 to about 200°C using a hot air dryer, a vacuum constant temperature dryer, etc.
Preferably, a method of maintaining the temperature between room temperature and 100°C is employed. Further, it is also possible to use a method of heating the substrate coated with the solution on a hot plate in a dust-proof hood, a method of heating using an infrared lamp, and the like.

In the present invention, the solvent for cleaning the conductive polymer film is preferably methanol, a mixed solvent of methanol and THF, or the like.

In the present invention, the conductivity of the stream obtained by cleaning is 10-”S/C
A neutral film of about I can be doped by immersing it in a salt solution having various anions as counterions.

Examples of the salt include Lewis acids such as FeC11,5nCIa, strong acids such as trichloroacetic acid, trifluoroacetic acid, methanesulfonic acid, benzenesulfonic acid, P-)luenesulfonic acid, hydrochloric acid, sulfuric acid, and IC104.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.
This does not limit the present invention in any way.

Example 1 0.215 g (1,0×10-mol) of benzyl rubonate was added to 0.487 g of FeCl5
g (3,OX10-'so summer) and dry ether 10
#j! Add a solution of
A black polymer was obtained.

Put the black polymer (on the glass plate) into a beaker and add 100
The organic solvent of d was added and stirred with a stirrer. Since it immediately became a yellowish brown solution, it was decanted, and 100 ae of the same pure solvent was added and stirred. Repeat this operation from 4 to
After 5 repetitions, the solution was no longer colored and was considered the end point. After drying, the Fe content was determined by atomic absorption spectrometry. The results are shown in Table 1.

It was found that methanol and methanol/THF in Table 1 showed good cleaning effects. Also, 10-'S/cm from the color of the film
It was also found that it was in a somewhat neutral state.

The polymerized film was peeled off from the substrate and thoroughly washed with methanol. After drying, the electrical conductivity and Fe content of the film were measured, and the electrical conductivity was about 10-''S/cm, and the Fe content in the film was 0.1% or less (by atomic absorption method).

The washed film was immersed in a solution of 1520 mg of FeC/10 d of ether and 10 d of 5 nCIs Ig/nitromethane at room temperature (25°C) for 5 hours, washed with each pure solvent, dried in a desiccator day and night, and immediately conductive using the four-terminal method. The sex was measured. The results are shown in Table 2.

Table 2 [Effects of the invention] The polymer film obtained by the cast film forming method of the present invention is as follows:
By washing with a solvent, a neutral film of about V 10-' S /1 can be obtained. Chemical doping can be easily performed by simply immersing this neutral film in a solution of various anion salts.

For various anion species, if a functional group having photosensitivity, electrical sensitivity, etc. is selected, a functional conductive polymer can be easily obtained.

Claims (1)

[Claims] A homogeneous and stable solution containing an aromatic compound, an oxidizing agent, and a solvent is prepared, and the solution is applied onto a substrate.The solvent is then evaporated off to produce a conductive polymer film. A method for chemical doping of polymeric films, characterized by washing the film with a solvent to make it a neutral film, and then immersing it in a salt solution.