JPH0236131B2 - HAIKOSHITADODENSEIHORIPIROORUSEIKEIBUTSU - Google Patents

Description

[Detailed description of the invention]

The present invention relates to oriented conductive polypyrrole moldings. Although organic polymer compounds are generally classified as insulators, it has become clear that by adding certain compounds, they become conductive organic polymer compounds and can be used as semiconductors or conductors. It has become clear that these conductive polymers can become p-type or n-type semiconductors depending on the type of additive, and can be applied to electronic materials, batteries, etc. in combination with various semiconductors. Examples of such organic polymer compounds include polyacetylene, polypyrrole, and poly-p-phenylene. However, conductive polymers made from these organic polymer compounds are insoluble and infusible, making it difficult to obtain products in the desired form, which poses an obstacle in terms of application. Among the above polymers, polypyrrole is a noteworthy conductive polymer due to its high conductivity and stability in air. This highly conductive polypyrrole can be produced using an electrolytic oxidation method using platinum or gold as an anode (AFDiaz and KK Kanazawa, JCSChem.
Comm., 1979, 635), it is known that it can be obtained by depositing an insoluble and infusible polymer molding on the anode surface. However, the electrical conductivity of the polypyrrole film thus obtained cannot be said to be sufficiently high. As a result of extensive research into methods for improving the conductivity of conductive polypyrrole molded products such as conductive polypyrrole films obtained as described above, the present inventors found that conductive polypyrrole highly oriented in at least one direction. The present invention was achieved by discovering that the molded product has extremely high conductivity. Therefore, an object of the present invention is to provide a highly conductive polypyrrole molded product, and further to provide a photoconductive polypyrrole molded product, particularly a film-like molded product, having a high degree of orientation. As described above, this object of the present invention is achieved by stretching a non-oriented or slightly oriented conductive polypyrrole molded product in at least one direction to form a conductive polypyrrole molded product having a high degree of orientation. In the present invention, a conductive polypyrrole molded product is one in which polypyrrole itself is doped,
It has a certain degree of conductivity,
There are various shapes such as thread-like, rod-like, and film-like. The polypyrrole constituting the above-mentioned conductive polypyrrole refers to pyrrole and its derivatives, especially N-
It refers to homopolymers and copolymers obtained from alkyl derivatives, preferably homopolymers from pyrrole. The dopant that cooperates with the polypyrrole to exhibit electrical conductivity is a compound that is electron-accepting to the polypyrrole, and specifically includes the following compounds. i.e. halogen anions such as Cl ^- , Br ^- and I ^- ; peracid anions such as ClO ₄ ^- ;
Anions of protonic acids such as sulfate anion, nitrate anion, phosphate anion; BF ₄ ^- , PF ₈ ^- ,
Anions formed from Lewis acids such as AsF ₅ ^- , SbF ₅ ^- ; HCOO ^- , CH ₃ COO ^- , HOOC・COO ^- ,
CH ₂ Cl・COO ^- , CHCl ₂ COO ^- , CCl ₃ COO ^- and
Anions formed from organic carboxylic acids such as CF ₃ COO ^- ; CCl ₃ SO ₃ ^- , CF ₃ SO ₃ ^- , CH ₃ SO ₃ ^- and
CH ₃

Examples include anions formed from organic sulfonic acids such as: In the present invention, doping or doping refers to a phenomenon in which the above-mentioned compounds are added to polypyrrole and they work together to develop higher conductivity. It is not limited. Therefore, in most cases, the polypyrrole and the compound form a chemical bond such as a complex, but in other cases, a mere mixed state may be included. The conductive polypyrrole formed from such a polypyrrole and a dopant may be said to be non-oriented immediately after being formed. Although a conductive polypyrrole molded product exhibits a certain degree of conductivity even in a non-oriented state, the present invention provides a conductive polypyrrole molded product in which such a non-oriented or low-oriented conductive polypyrrole molded product is highly oriented in at least one direction. By doing so, it is possible to obtain a conductive polypyrrole molded product with extremely high conductivity. This highly oriented conductive polypyrrole molded product can be easily obtained by stretching. The stretching is carried out in a state where the polypyrrole contains a dopant, that is, in a state where it is a conductive polypyrrole molded product. Further, the above-mentioned stretching can be carried out in air or in a dry atmosphere such as nitrogen gas, but it can also be carried out in a gas phase of water, an aqueous solvent, and an organic solvent, or in a wet state where these are present in liquid form. Note that the solvent used in the present invention does not have the meaning of dissolving polypyrrole. Preferred substances for forming a wet state have a boiling point of, for example, 0°C to 250°C, preferably 10°C.
It is a liquid substance in the range of ℃ to 200℃, and it does not impair the conductivity of the conductive polypyrrole. Conductivity may be impaired if the dopant acts on the dopant, for example, if it chemically reacts with the dopant, making the dopant unable to perform its original function (for example, highly basic solvents such as aliphatic amines or alkaline solutions). ), and cases where they act on polypyrrole, such as chemically bonding or chemically decomposing them, making it impossible for polypyrrole to perform its original function (e.g., concentrated sulfuric acid, concentrated nitric acid). The substances that form the gas phase or form a wet state include (i) n-hexane, cyclohexane, heptane,
Hydrocarbon compounds such as benzene, toluene, and xylene (ii) Chlorinated hydrocarbon compounds such as dichloromethane, 1,1,1-trichloroethane, and chlorobenzene (iii) Nitrile compounds such as acetonitrile, propionitrile, and benzonitrile Class (iv) Ketone compounds such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexane (v) Ether compounds such as anisole, tetrahydrofuran, dioxane, butyl ether, and butyl cellosolve (vi) Nitro compounds such as nitromethane and nitrobenzene (vii) ) Ester compounds such as ethyl acetate, n-butylacetic acid, propylene carbonate, and propiolactone (viii) Alcohol compounds such as methanol, ethanol, butanol, and ethylene glycol (ix) Organic acid compounds such as acetic acid and propionic acid Class (x) Aromatic amine compounds with low basicity such as pyridine and aniline () Aprotic polar organic compounds such as N,N-dimethylformamide, dimethyl sulfoxide and sulfolane () Water and neutral salts and alcohols Examples include aqueous solvents. These materials may be used alone or in combination. Among these, preferred are the groups (i) to (ix) and the group () above. To stretch in the gas phase of these substances or in a state moistened by them, the most convenient method is to immerse the conductive polypyrrole molded product in a liquid of these substances,
Examples include a method of stretching while immersed, and furthermore,
It is also possible to stretch the conductive polypyrrole molded product sufficiently impregnated with these substances even if not in a liquid, or to stretch the conductive polypyrrole molded product exposed to the vapor of these substances. Good too. The temperature at which the stretching is performed in a dry atmosphere such as nitrogen gas in the air, or in the vapor phase of the solvent or in a wet state depending on the type of dopant and whether it is in a dry or wet state, Although the condition varies depending on the wet material, it is usually 0°C to 300°C,
Preferably from 10°C to 200°C, particularly preferably from 20°C
The temperature is 150℃. It is preferable that the stretching ratio be as high as possible, but it is usually 30% when stretching in a dry state in an air or nitrogen atmosphere.
~100%, preferably 50% to 90%, usually 50% for stretching in a solvent vapor phase or in a wet state with a solvent
or more, preferably 60% or more, more preferably 80%
That's all. In addition, due to manufacturing stability, the stretching ratio is
It is 300% or less, preferably 200% or less, particularly preferably 150% or less. The stretching speed is 0.5%/sec to 1000%/sec, preferably 5%/sec to 100%/sec. The conductive polypyrrole molded product stretched at such a magnification may be heated to 50°C to 300°C, preferably
Heat setting is carried out at a temperature of 100° C. to 250° C. for 1 minute to 1 hour, preferably 5 minutes to 0.5 hour. Although heat fixation may be carried out under no tension, it is preferably carried out under tension. Thus, the half-width of the intensity distribution along 2θ of the orientation peak by X-ray diffraction is Ho, and the orientation degree calculated by the formula f (degree of orientation) = [(180−Ho)/180] × 100 (%) is A polypyrrole molded product having a conductivity of 60% or more, preferably 70% or more can be obtained. Conventionally known methods can be applied as they are to synthesize the polypyrrole used to obtain the highly oriented conductive polypyrrole molded product of the present invention.
For example, pyrrole and/or its derivatives are prepared by using a platinum plate as the working electrode (hereinafter referred to as WE) and a platinum plate as the counter electrode (hereinafter referred to as CE) in an electrolyte solution consisting of an electrolyte, a solvent, and a small amount of water if desired. Alternatively, using conventionally known general-purpose materials, AFDias andK.
K. Kanazawa, JCSChem.Comm.1979, 635 and KKK Kanazawa et al., Synthetic Metals, 1
(1979/80) 329-336. The raw materials pyrrole and its derivatives used in the above reaction preferably have high purity, and are preferably purified by distillation before use. Examples of pyrrole derivatives include C ₁ to ₅ N-alkyl derivatives, N-phenyl derivatives, pyrrole ring β
_C1-5 alkyl substituent, alkoxy _substituent ,
Examples include substituted phenyl derivatives. The same method as above is also employed when producing polymers from these pyrrole derivatives. The electrolyte used in the above reaction is
Examples include salts in which the dopant is an anion, such as quaternary ammonium salts and alkali metal salts. For example, tetraethylammonium bromide, tetraethylammonium iodide, tetraethylammonium perchlorate, tetrafluoroborate, tetraethylammonium p-toluenesulfonate, tetra-n-butylammonium bromide, tetra-n-butylammonium iodide, Tetra n-butylammonium perchlorate,
Tetra-n-butylammonium tetrafluoroborate, tetra-n-butylammonium p-toluenesulfonate, tetra-n-butylammonium hydrogen sulfate, lithium perchlorate, lithium nitrate, lithium tetrafluoroborate, sodium perchlorate, Examples include tetrabutyl-n-ammonium acetate. The required amount of these electrolytes is such that the electrolyte is dissolved as a solution and the electric current necessary for the reaction to proceed is obtained, and the minimum amount is 0.1 for pyrrole.
The amount is at least a molar equivalent, preferably at least 0.3 molar equivalent, and the maximum amount is the amount at which the electrolyte is saturated as an electrolytic solution. Of course, there is no problem even if there is something more than that. The electrolyte concentration in commonly used electrolytic solutions varies depending on the solvent, the type of electrolyte, and the amount of water used if desired, but is usually from 0.001 M/l (mol/l).
2M/l, preferably from 0.05M/l
It is 0.5M/l. The solvent used in the reaction is stable under the voltage required for polymerization of pyrrole compounds,
High solubility in electrolytes and water is required. Examples of such solvents are acetonitrile,
Examples include, but are not limited to, benzonitrile, hexahydrofuran, nitrobenzene, propylene carbonate, hexamethylphosphoramide, etc.
As long as the above conditions are met, conventionally known materials are generally used in electrolytic reactions. The role of water, which is optionally used, is to increase the effectiveness of the electrolyte and to improve the form in which polypyrrole is precipitated. The amount used varies depending on the type of electrolyte used, and the concentration of water in the electrolyte solution is
0.1 M/l to 5 M/l, preferably 0.3 M/l to 3 M/l. The cathode material used in the reaction may be any general-purpose material as long as it does not cause defects or alterations in the electrode reaction, and is not particularly specified, but platinum, platinum,
In addition to metals such as gold, copper, and nickel, SnO ₂ , In ₂ O ₃ , or similar conductive materials, and carbon electrodes with larger diameters generally produce better polypyrrole precipitation. The ratio of the cathode to the anode surface area is preferably 1.1 times or more, preferably 1.5 times or more, more preferably 2 times or more, particularly preferably 3 times or more. The electrolytic voltage and electrolytic current are not constant depending on the reaction conditions, but in general, the electrolytic voltage is 1.0 volt or higher.
The voltage is preferably 1.5 volts or more, particularly preferably 2 volts or more, and desirably 3.0 volts or less in view of the stability of the electrolytic reaction solvent. The electrolytic current is 0.001 mA/cm ² to 5 mA/cm ² as a current density at the anode, preferably
0.01mA/ ^cm2 to 3mA/ ^cm2 , particularly preferably
It is 0.5mA/cm ² to 1mA/cm ² . Preferably, the temperature of the entire reactor can be controlled. The reaction temperature is not particularly limited, but is usually
It is carried out at a temperature of 100°C or lower, preferably 50°C or lower, particularly preferably 0°C or lower - 50°C or higher. In particular, a polypyrrole molded product obtained by reaction at a low temperature is suitable because a product having a high stretching ratio can be obtained in the above-mentioned stretching. When a polypyrrole molded product is obtained by the above electrolytic reaction, a part of the dissociated anions of the electrolyte used are incorporated into the polypyrrole molded product, which itself acts as a dopant, and is used as a conductive polypyrrole as it is. This acts to give a conductive polypyrrole molded product as it is. The polypyrrole molded product (film) used in the present invention can be produced by the following method (KKKanazawa et al. (JPS.
Poly.Lett.Edd.1982.187)) can also be obtained. That is,
A solution of 2 ml of pyrrole and 10 ml of ethanol was poured into 1.9N sulfuric acid in a Petri dish under stirring and left to stand for 15 hours to form a film of polypyrrole on the surface. In this case as well, polypyrrole contains sulfate ions as a dopant, so
It becomes a conductive polypyrrole molded product as it is. The conductive polypyrrole molded product thus obtained may be subjected to the above-mentioned stretching treatment as it is, but in some cases, the dopant contained during the reaction may be replaced with a desired dopant. In particular, when it is desired to use a halogen atom or the like as a dopant, stretching can be performed after dopant substitution. To replace the dopant, first remove the dopant from the polypyrrole electrochemically, that is, by electrolytic reduction of the polypyrrole, and then add the desired dopant to the polypyrrole by a gas phase method or a liquid phase method. Bye. The object of the present invention is achieved by subjecting the non-oriented or low-oriented conductive polypyrrole molded product thus obtained to the above-described stretching treatment. The present invention will be further explained below using specific examples. The electrical conductivity in the example was determined using a four-terminal method using a digital voltmeter manufactured by Heuretsu Patscard.
Calculated from the voltage measured using 3456A. The degree of orientation is determined by the above formula, and is the value at 2θ=0.4475 unless otherwise specified. In the example, X-rays were measured using a Rigaku X-ray diffraction device (No. 4053A3) using CuKa rays as the radiation source, and measuring the transmitted X-rays of a sample with a thickness of about 500 μm using a scintillation counter according to the usual method. I went and measured it. Example 1 A separable 300 ml glass electrolytic cell equipped with two electrode inlets, a nitrogen inlet pipe, and an exhaust port has a platinum plate with a length of 5 cm and a width of 4 cm as an anode, and a platinum plate with a width of 5 cm as a counter electrode.
A copper foil with a length of 40 cm was installed. The entire electrolytic cell was immersed in a cooled bath so that the temperature could be controlled. Next, 200 ml of a propylene carbonate solution containing 0.06 mol/l of pyrrole and 0.1 mol/l of tetraethylammonium perchlorate and 2 ml of water were placed in the electrolytic cell. While introducing nitrogen bubbles into the solution at -20°C, at 3.2 mA (current density = 0.08 mA/cm ² ).
Synthesized for 36 hours. Then tetraethylammonium perchlorate 0.1
It was transferred to a propylene carbonate solution (hereinafter referred to as a retentate) cooled to -20°C containing mol/l, and after returning to room temperature, it was peeled off from the electrode. The resulting film had a thickness of 23 μm and an electrical conductivity of 295 S/cm. This film was immersed in 50 ml of acetonitrile for 1 day, then taken out and dried at 40°C for 15 hours. next,
Slit the film into strips with a width of 5 mm, hold them at a distance of 20 mm between the chucks, and store them in air at room temperature for 2 minutes.
The film was stretched by 90% at a speed of %/sec. Next, it was transferred to a hot air dryer at 150°C and heat-set for 5 minutes. The electrical conductivity of the obtained film in the stretching direction is
It was 896S/cm. An orientation peak appeared in the X-ray diffraction pattern of this film, and the degree of orientation was 72.3%. Example 2 A conductive polypyrrole film was prepared using the same equipment and operation as in Example 1. The electrical conductivity of this film was 280 S/cm. Next, this film was immersed in a holding solution heated to 70°C, preheated for 1 minute, stretched 90% at a rate of 50%/second, and then heat-set at 150°. The electrical conductivity of the obtained film was 1050 S/cm, and the degree of orientation was 75.4%. Example 3 Using p-toluenesulfonic acid tetraethylammonium salt as the electrolyte and acetonitrile as the solvent, react it at -20°C in the same manner as in Example 1, take it out in the acetonitrile solvent, and check the electrical conductivity.
A film of 130S/cm was obtained. When this was stretched by 40% in the same manner as in Example 1, the electrical conductivity in the orientation direction was 320 S/cm. The degree of orientation is
It was 71.2%. Examples 4 to 6 Polypyrrole films were prepared using the same equipment and operations as in Example 1. This film was immersed in the solvent shown in the table below at room temperature for 3 days, and then stretched 120% in this solvent at 40° C. at a stretching rate of 2%/sec. The electrical conductivity and degree of orientation in the stretching direction of the polypyrrole film after stretching were as shown in the table below.

[Table] Examples 7 to 20 Polypyrrole films were prepared using the same equipment and operation as in Example 1. This film was immersed in the stretching solvent specified in the table below at room temperature for 3 days. Next, the film was stretched 100% in this solvent at a stretching temperature of 40°C and a stretching rate of 2%/sec. The electrical conductivity of the stretched polypyrrole film in the stretching direction was measured. Additionally, all of these films have a degree of orientation of 60%.
That's all.

【table】

[Table] Example 21 Except for using a 20-hour reaction instead of a 36-hour reaction,
A conductive polypyrrole film was produced by performing the same synthesis reaction as in Example 1. This product was subjected to dedopant treatment for 20 hours by applying 2V in an electrolytic bath containing a propylene carbonate solution containing 0.03 mol/l of tetraethylammonium bromide, with the electrode connections reversed to those used during film formation. As a result of fluorescent X-ray analysis, only trace amounts of perchlorate were detected in this material, and the conductivity was 10 ^-5 S/cm.
It was below. In an electrolytic cell solution containing a new tetraethylammonium bromide (0.03 mol/l)-propylene carbonate solution, the electrodes were connected again in the same manner as during film formation, and 3V was applied to react for 20 hours. The conductive polypyrrole film thus obtained had a thickness of 35 μm and an electrical conductivity of 28 S/cm. This film was prepared in the same manner as in Example 1 (however,
The film obtained by stretching 100% (at a temperature of 40°C) and heat setting had an electrical conductivity of 1080 S/cm in the stretching direction and a degree of orientation of 74.2%. Example 22 A conductive polypyrrole film was obtained by the same synthesis reaction as in Example 1. This film was immersed in acetonitrile for 24 hours and then dried at 40°C for 12 hours. The thus obtained dried conductive polypyrrole film was exposed to the boiling gas phase of the solvent listed in the table below and stretched 100%. The degree of orientation of these films was all 70% or more. Further, the electrical conductivity is shown in the table.

【table】

Claims (1)

[Claims] 1 The degree of orientation in at least one direction is 60% or more,
An oriented conductive polypyrrole molded product having an electrical conductivity of 300 S/cm or more.