JPH01280528A - Manufacture of oriented polypyrrole film having improved conductivity - Google Patents

Abstract

PURPOSE:To obtain an oriented polypyrrole film having improved conductivity, by a method wherein a nonoriented or low oriented polypyrrole film is oriented or rolled in an inactive gas at least in one direction. CONSTITUTION:An example of an orienting method is performed by extending the same while tensing it by holding both ends of the same. An orientation speed is 0.01%/min-200%/min, preferably 0.5%/min-20%/min, orientation atmosphere and a temperature are performed within air at 0 deg.C-300 deg.C, preferably within inactive gas such as nitrogen gas at 20 deg.C-100 deg.C especially preferably. A draw ratio is at least 5%, especially preferably at least 20%, not exceeding 95% of the maximum draw ratio, preferably not exceeding 90% of the same. The other example of an orientation method is performed between rotating rollers under pressurization. A peripheral speed of the roller in this instance is 0.1mm/min-1,000mm/min, especially preferably 1mm/min-10mm/min and pressure between the rollers is preferably 50kg/cm<2>-500kg/cm<2>.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to oriented polypyrrole films. Organic polymer compounds are generally classified as insulators, but it has become clear that they can become semiconductors or conductors by adding certain compounds. It has become clear that these polymers can be combined with p-type or n-type semiconductors and various types of semiconductors and applied to electronic materials, batteries, etc. by selecting additives. Examples of these polymers include polyacetylene, polypyrrole, and poly-p-phenylene. However, these conductive polymers are insoluble and invulnerable, and it is difficult to obtain products in the desired form, which poses an obstacle in terms of application. Among the above polymers, polypyrrole is a conductive polymer that is noteworthy because of its high conductivity and stability in air. This highly conductive polypyrrole can be produced using electrolytic oxidation methods (A, F, Diax and K, K) using platinum or gold as an anode.
, Kanazawa, J., C.S.

Chem, Comm, 1979.635), it is known that this can be obtained by depositing an insoluble and infusible polymer film on the anode surface.

The oriented polypyrrole film having enhanced electrical conductivity of the present invention can be obtained by stretching or rolling a polypyrrole film obtained by the following or other methods in at least one direction in an inert gas.

That is, the present invention is a method for producing an oriented polypyrrole film having enhanced electrical conductivity, which comprises stretching or rolling a non-oriented or slightly oriented polypyrrole film in at least one direction in an inert gas.

The polypyrrole used as a raw material in the present invention is a polymer or copolymer obtained from virol and its derivatives, particularly an N-alkyl dielectric, and preferably a homopolymer mainly composed of virol. There are various methods for synthesizing it. For example, virole and/or its dielectric material is placed in an electrolyte solution consisting of an electrolyte, a solvent, and optionally a small amount of water, and a working electrode (hereinafter referred to as WE) is coated with platinum or a conventionally known method. It is obtained by reacting under specific conditions using general-purpose materials.

The pyrrole and its derivatives used in the present invention preferably have high purity, and are preferably purified by distillation before use. Examples of pyrrole derivatives include C1-5 N-alkyl derivatives, N-phenyl derivatives, alkyl-substituted products, alkoxy-substituted products, and phenyl-substituted products at the β-positions of the pyrrole ring. The same method described above is also employed when producing polymers from these pyrrole derivatives.

The electrolyte used in the reaction is preferably one that allows the electrolytic oxidation reaction to proceed and when homogeneous polypyrrole is deposited on the anode surface, the polypyrrole exhibits high electrical conductivity.

The required amount of these electrolytes is such that the electrolyte is dissolved in the form of a solution and that the electric current necessary for the reaction to proceed is obtained, and the minimum amount is 0.1 molar equivalent or more, preferably 0.3 molar equivalent to pyrrole. The amount is more than the molar equivalent, and the maximum amount is the amount at which the electrolyte is saturated as an electrolytic solution. The electrolyte concentration in commonly used electrolyte solutions varies depending on the solvent, type of electrolyte, and amount of water used, but is usually 0.001.
M (mol/1> to 2M, preferably 0.05
It is 0.5M from M. Examples of such electrolytes include quaternary ammonium salts and alkali metal salts of various anions. For example, tetraethylammonium bromide, tetraethylammonium iodide, tetraethylammonium perchlorate, tetraethylammonium tetraroborate, tetraethylammonium p-toluenesulfonate, tetralobylammonium bromide, tetran-butylammonium iodide, n-perchlorate. -butylammonium, tetrafluoroborate, tetra-n-butylammonium, p-)luenesulfonate, tetra-n-butylammonium hydrogen sulfate, lithium perchlorate, lithium nitrate, lithium tetrafluoroborate, perchlorine There are lithium oxides, etc.

A portion of these separated anions of the electrolyte are present within the polypyrrole as additives to the polypyrrole, forming the polypyrrole film.

The solvent used in the reaction needs to be stable under the voltage required for polymerization of the virol compound and have high solubility in the electrolyte and water.

Examples of such solvents include, but are not limited to, acetonitrile, benzonitrile, tetrahydrofuran, nitrobenzene, propylene carbonate, hexamethylphosphoramide, etc. If the above conditions are met, -m can be used in electrolytic reactions. are used.

The role of water used as required is to have an electrolyte effect,
This improves 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 from 0.1M to 5M, preferably from OjM to 3M.

The cathode material used in the reaction is deficient in the electrode reaction,
Any general-purpose material may be used as long as it does not undergo deterioration, and there are no particular limitations. In addition to metals such as platinum, gold, copper, and nickel, conductive materials such as 5n02, In2O3, or similar conductive materials, and carbon electrodes. etc. are used. In addition, when the electrode area of the cathode is larger than that of the anode, the state of precipitation of polypyrrole that is generally produced is better. 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.

Although the electrolysis voltage and electrolysis current are not certain depending on the reaction conditions, the general electrolysis voltage is 1.0 volt or more, preferably 1.0 volt or more.
．． The voltage is 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 0.01 mA/cm2 as the current density at the anode.
~5mA/cm2, preferably 0,1mA/cm
2-3 mA/Cm2, particularly preferably 0.5 mA
/ Cm2 ~ 1 mA/Cm2.

The polypyrrole film used in the present invention can also be prepared by the method shown in the following [K, K, Kanazawa et al., J, P,
S.

Poly, Lett, Ed. (1982)
187]. That is, a solution of 2 ml of pyrrole and 10 ml of ethanol is 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. This polypyrrole contains sulfate ions as a dopant.

The polypyrrole film obtained as described above is
The oriented polypyrrole film of the present invention, which is not linearly oriented, can be stretched or rolled in at least one direction to obtain an oriented polypyrrole film exhibiting high conductivity.

An example of a stretching method is to hold both ends of the film and stretch it while applying tension.9 The stretching speed is 0.01.
%/min to 200%/min, preferably 0.1%/min to 10
0%/min, particularly preferably 0.5%/min to 20%/min, and the stretching atmosphere and temperature are in air, preferably in an inert gas such as nitrogen gas, and 0°C to 300°C, preferably between 10°C and 200°C, particularly preferably between 20°C and 10°C
It is carried out between 0°C.

The stretching ratio is 5% or more, preferably 10% or more, particularly preferably 20% or more, and 95% or less of the maximum stretching ratio,
Preferably it is 90% or less. The polypyrrole film that has been stretched to a certain extent may be held without being held, but
-i is preferably heat-fixed. The heat setting temperature varies depending on the purpose, but is usually set at a temperature higher than the stretching temperature and lower than 600°C.

Another example of the method of stretching can be carried out under pressure between rotating rollers.

In this case, the roller circumferential speed is 0.1 mm/min to 1000
mm/min, preferably 0.5m++/min to 100mm
7 minutes, particularly preferably Inn/min to 10 mm/min, and the temperature, atmosphere, etc. are the same as the above conditions.

The pressure between the rollers is 10Kg/cm to 1000Kg/
cm, preferably 50Kg/Cm to 500Kg/
cm.

Another example of a stretching method is between flat surfaces under pressure.

The applied pressure in this case is 10Kg/cm2 to 1000Kg/
cm2, preferably 50Kg/cm2 to 500Kg/
cm2.

The oriented polypyrrole film obtained as described above shows an orientation peak in the XtI diffraction pattern,
The electrical conductivity in the orientation direction is also improved compared to those with no orientation or low orientation.

Taking the case of a virol homopolymer as an example, a film that is unoriented in X-rays and has an electrical conductivity of 1 to 100 S/cm is stretched in a direction perpendicular to the stretching direction (equatorial direction). at least 0.38 to 0.48 in 2θ,
The film has an orientation diffraction peak with an orientation degree of 40% or more, preferably 50% or more, and its electrical conductivity is also 10.
It comes to show performance of 0 S/cm or more.

Here, the degree of orientation is determined according to the following formula, where Ho is the half-width of the intensity distribution along 2θ of the orientation peak.

180-H" f (degree of orientation) = -x 100 (%)] In other words, the oriented film has an electrical conductivity of 1.1 times or more, preferably 1.5 times or more, of the electrical conductivity before orientation. becomes.

The present invention will be specifically illustrated in Examples below.

The electrical conductivity in the example was calculated from the voltage measured using a digital voltmeter 3456A manufactured by Hewlett-Paracard Co., Ltd. by the four-terminal method.

In the example, measurements using X-rays are performed using a Rigaku X-ray diffraction device (No.
, 4053A 3) using Cu-Ka radiation as a radiation source,
The measurement was carried out by measuring transmitted X-rays of a sample having a thickness of approximately 500 μm using a scintillation counter in accordance with a conventional method.

Example 1 In a 300 ml glass electrolytic tank in a separable flask equipped with two electrode insertion ports, a nitrogen gas inlet pipe, and an exhaust port, a platinum plate with a length of 5 cm and a width of 4 cm as an anode, a platinum plate with a width of 5 cm as a counter electrode, and a platinum plate with a width of 5 cm as an anode. A copper foil with a length of 40 cm was installed. Next, 200 ml of a propylene carbonate solution containing 0.06 mol/i of pyrrole and 0.1 mol/i of tetraethylammonium perchlorate and 2 ml of water were placed in the electrolytic cell. While introducing nitrogen into the solution in the form of bubbles, 40 mA (
was reacted for 3 hours at a flow density of 1 mA/cm2).

After the reaction was completed, the anode was taken out and washed with propylene carbonate and then acetone, and the black polypyrrole film was peeled off from the platinum plate.

This film has a thickness of 35μ and an electrical conductivity of 85.
It was 63/cm.

This film was slit into strips with a width of 5 mm, held at a chuck pressure of 1111!20 mm, and 30 mm at 100%/min.
% and heat set at 150°C for 5 minutes. The electrical conductivity of the obtained film was 154.93/cm, and its X-ray photograph (transmission observation direction) showed that the film was oriented at 2θ = 0.40 to 0.48 in the direction perpendicular to the stretching direction (equatorial direction). A pattern is visible, and the degree of orientation at 2θ = 0.4475 is 58
．． It was 8%. The photographs were taken using a powerful X-ray diffractometer D3F manufactured by Rigaku Denki Co., Ltd. and at a camera distance of 5 cm using a Cu tube manufactured by Philips.

Example 2 Same composition as Example 1, current density 0.35 mA/cm
When the reaction time was increased to 2 and reacted for 3 hours, a film with a thickness of about 12 μm was obtained. Its conductivity was 146.33/cm.

Slit this film into 5mm strips and check the chuck pressure! Grip with 20mm, stretch 30% at 2%/min, 15
After heat setting at 0°C for 5 minutes, the electrical conductivity was measured and found to be 271. OS/cm. 2θ=0.44
The degree of orientation at 75 was 59.3%.

Example 3 A reaction was carried out in the same manner as in Example 1 using p-)luenesulfonic acid tetraethylammonium salt as the electrolyte and acetonitrile as the solvent to obtain a polypyrrole film having an electrical conductivity of 60.78/cm. When this was stretched 50% at a rate of 50%/min and heat-set at 150°C for 5 minutes, the electrical conductivity of the film was 113.8 S/cm. The X-ray diffraction photograph of this film shows 2θ in the direction perpendicular to the stretching direction.
An oriented diffraction pattern was observed at the position of =0.42 to 0.48. The degree of orientation at 2θ=0 and 4475 is 57.
It was 5%.

Example 4 The electrical conductivity of a film obtained in the same manner as in Example 1 except that pyrrole was replaced with 1-methylpyrrole was 1.3×103S 7
It was cm. When this was stretched 30% at a speed of 0.5%/min, the electrical conductivity was 5. IX 1O-3S/c
It became m.

The degree of orientation at 2θ-0,4475 was 43.2%.

Example 5 The film used in Example 1 was heated to 100' (, 'c linear pressure 40
It was rolled at 0 Kg/cm.

The electrical conductivity of the obtained film was 129.3S/cm
Met.

The degree of orientation at 2θ=0.4475 was 48.1%.

Example 6 Thickness 35 μm and electrical conductivity 85.6 S/ obtained in Example 1
A 15% stretching film was used. The electrical conductivity of the obtained film was 97.6S 7 cm, and the degree of orientation was 41.8%.

Claims (2)

[Claims] (1) A method for producing an oriented polypyrrole film with enhanced electrical conductivity, which comprises stretching or rolling a non-oriented or slightly oriented polypyrrole film in at least one direction in an inert gas. (2) Claim 1 in which the degree of orientation f is 40% or more
A method for producing an oriented polypyrrole film having enhanced electrical conductivity. [Here, the degree of orientation f is defined as the half width of the intensity distribution along 2θ at the orientation peak in the equator direction of the X-ray diffraction photograph of the film in the range of 0.38 to 0.48. , was calculated according to the following formula. f (degree of orientation) = (180-H°)/(180) x 100
(%)]