JPS6296525A - Preparation of thin-film polyaniline - Google Patents

Abstract

PURPOSE:To obtain a thin-film polyaniline which is uniform and has excellent mechanical strength and an improved life, by polymerizing aniline dissolved in an aqueous sulfuric acid solution by electrolytic oxidation to form a thin film. CONSTITUTION:A 5-12N aqueous sulfuric acid solution containing a predetermined amount of aniline is first prepared. This solution as an electrolyte solution 5 is placed in an electrolytic cell 4, a cell 15 and a salt bridge 16. A potential difference between a platinum plate 7 as a cathode and a reference electrode 13 is measured with a potentiometer 14, and zero adjustment is made with a zero indicator. After making such preparations, a power source 8 is on and the aniline is polymerized by electrolytic oxidation under conditions of a current of 0.1-5mA/cm<2> and an application time of about 1sec-120min. By keeping the value of the current of a circuit 9 constant by adjusting a rheostat 12 and at the same time keeping the potential of the metal plate 7 as the cathode constant during the polymerization, a thin-film polyaniline of a desired thickness is formed on a metal plate 6 as an anode.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method of forming a polyaniline thin film on the other side of a surface by decoupling aniline in a VL decomposition bath solution. #c Crushed mechanical heel and uniformity in one direction
Polyaniline iLQ J that can be used for one cycle in electrochromic tabo elements with a long discoloration life and a lifespan of Dj
k Method of creating polyaniline thin film that can be obtained)
This is related to this.

(Prior art and its problems) Conventionally, the method for producing such a polyaniline thin film was as follows:
1 to 2N of salted water containing a certain amount of aniline gold is used as an electrolytic bath residue (for example, a platinum plate for an electrode and a platinum plate for a cathode). A method (J, Electroan) of applying a predetermined voltage to a platinum plate for an anode.
al Chem, 161 (1984) 419)
A method of forming a polyaniline thin film on a platinum plate for an anode in the same manner as the above method using water Ld, which has been adjusted with sulfuric acid, sodium phosphorus, sodium hydroxide, etc. to have a pH of 1, as a solid bath liquid. (J, Elect-roanal
Chem, 161 (1984) 399) etc.

However, polyaniline τ that can be submerged by the former method
In the case of Himo, the uniformity of the pot in the above-mentioned plane direction is lacking, such as the polymerization waves being partially different along the plane direction of the platinum plate for 1. After the polymerization, the white kasa board for the anode is taken out from the decomposition bath and washed with water. When immersed in the 2N (/J r=acid ice water bath), the surface of the polyaniline thin film becomes d public. (There were problems with poor strength, such as peeling.

In addition, the polyaniline thin film obtained by the latter method has disadvantages in that it is inferior in physical strength, such as easy peeling on the surface, unlike the polyaniline 8 film obtained above, and is not suitable for electrochromic films. When a! function is enabled, there are problems such as the lifespan of discoloration is extremely short in practical use.

(Means for Solving Problem 1) Therefore, the method for producing a polyaniline thin film of the present invention is to use a solution having a concentration of 5 to 1
The above problem was solved by using a 2N sulfuric acid solution.

(Example of Fu S) Hereinafter, the method for producing a polyaniline thin film of the present invention will be explained with reference to the drawings.

The drawing shows an electrolytic device 11 suitably used in the method for producing a polyaniline thin film of the present invention, and the reference numeral 1 in the drawing indicates the electrolytic device. Does electrolyzer 1 contain aniline? It is a device for forming a thin polyaniline film by combining oxidized sheets of polyaniline, and it is roughly composed of an IIL 2 and a 1/1 fold 1f153.

First, the electrolytic section 2 consists of an electrolytic cell 4, an electrolytic bath liquid 5, a platinum plate 6 for passing through the electrode, a platinum plate 7 for the cathode, and a power source 8.

The electrolyte solution tank 4 is a container for storing an electrolyte solution used in the chemical polymerization process. . Here, a sulfuric acid water bath solution is preferably used as the electrolyte solution 5, and its concentration is in the range of 5 to 12N. If it is less than 5N, the fitting surface of the obtained polyaniline thin film is likely to peel off, and the discoloration life of the polyaniline thin film as an electrochromic film is shortened.

On the other hand, if it exceeds 12 N'f, there will be problems such as lack of uniformity in the obtained polyaniline thin film, such as unevenness in the surface direction of the electrode.

The electrolyte solution 5 contains a dissolved aniline monomer, and its content is determined depending on the properties of the resulting polyaniline thin film, but is usually 0.1 to 1, Omol/L. The range is 7.

Further, inside the dL folding M4, a white sparrow plate 6 for %1# and a platinum plate 7 for cathode are respectively suspended, and these two gold plates 6,
7 are both immersed in [Pingyoreki Sou 5]. These platinum plates 6 and 7 are connected to a first contact terminal and a second contact terminal of a power source 8, respectively, to form a circuit 9. This circuit 9 includes date metal plates 6 and 7 in parallel with 'l4vA8.
A voltmeter 10 was thrown to measure the movement between the two
a current meter 11 for measuring rlLTA in the circuit 9 in series position with the power supply 8;

During polymerization, the potential of the cathode platinum plate 7 changes as the polymerization progresses, but at this time, if the negative potential is regulated, a current may flow in the early stage of electrolysis, so In order to maintain a certain level of return flow, a variable f-resistance grinder 12 is provided, which changes the resistance value.

On the other hand, the electrolytic A adjustment section 3 adjusts so that the electrolytic oxidation in the electrolytic section 2 can always be carried out under constant spiral flow conditions. It consists of the reference ctat3 and the fourth-place difference dt14.

The reference area 13 is used to know the reference voltage for the 4 (byeong cheng bath 5). g5
It has been destroyed. At 115, the electrolytic JIt bath liquid 5 is passed through the salt bridge 16 to the 'It solute bath liquid 5 of the growth scale inertia 4.
It is possible to send 4 letters. A position meter 14 for measuring the potential difference between the reference electrode 13 and the conventional platinum plate 7 is connected to the reference electrode 13 via a switch 17. Kanko tracometer 14 (an indicator that can correct the zero point of the potential difference between the reference IIL electrode 13 and the cathode platinum plate 7 measured in advance)
Although four units are provided, they are not shown.

Next, a method for producing a polyaniline thin film using such a four-component '-electrolyzer will be described. First, a 5-12N solution containing a predetermined amount of aniline is heated in a water bath.
4. L was prepared, and this was used as an electrolytic tank 4. Kei 1
5 and into the salt bridge 16. Next, 'I position difference meter 14
The potential difference between the platinum plate 7 for the cathode and the reference jIL 13 is measured using a meter, and zero point correction is performed using a zero indicator. i like this:! The four solutions of aniline are subjected to electrolysis under the conditions of a current of 0.1 to 5 mA/at and a current conduction time of 1 to 120 minutes. At this time, when the variable resistor 12 is adjusted to keep the flow rate of the Lgl path 9 constant, the potential of the cathode metal plate 7 is kept constant. A polyaniline thin film is formed on 6 to a predetermined thickness.

In the above embodiment, an anode and a thin platinum plate were used, but any metal plate that is not corroded by sulfur may be used. Historically, the method of electrolytic oxidation is not only carried out with a constant °ζ flow as described above, but also a method of amending the current so that a constant pressure l is applied between the reference electrode and the # electrode may be used.

Hereinafter, an experimental example will be shown to clarify the effects of the method for producing a polyaniline thin film of the present invention.

(Experiment example) 5 to 12 where the government rent of aniline is 0.25 mol/l
Using an aqueous solution of N as a solubilizing bath solution and using a platinum plate as an easy electrode and a dark electrode, constant current electrolysis was performed at a current of 0.5 mA/m for 2 minutes to form a film thickness of about 1 μm on the platinum plate of the anode. A polyaniline thin film was formed.

In addition, the total blind filtration of aniline is 0.25 m01/l5
In addition, a rash solution of over 12N and a hydrochloric acid bath solution of 8N or less were used as bathing agents, and Dingwang flow was performed under the same conditions as above to form 4 polyanilines. .

The following tests were carried out on each of the polyaniline thin films thus prepared, and the results are shown in Table 1.

Bottle uniformity test: During electrical bonding, the uniformity f in the polar surface direction was determined by visual inspection, and those with excellent uniformity were marked with O1, and those with non-uniformity were marked with an x.

(0) Mechanical strength vr, test: After polymerization, a polyaniline thin film was taken out, washed with water using ion exchange, and then thoroughly dried. A cellotape test was performed on the thin film. . Judgment was made from the amount of film attached to the viscous surface of the cellophane tape, and ○ indicates slight peeling or no advantage, and X indicates advantage.

? Appearance of long life... When the 'α-resolved bath used in electrolytic oxidative polymerization is soaked in an aqueous solution of IN hydrochloric acid, the '2' of the anti-silver reference electrode is removed.
IQQmsec at position fund OV, lOOm5ecy1r at +0.7 V.

A 5 Hz rectangular wave was applied to the polyaniline thin film to maintain the temperature. Then, monochromatic light of 740 nm at an incident angle of 45° was irradiated onto the platinum plate on which four layers of polyaniline were formed, and the reflected light was received by a total detector to measure the change in reflectance. The lifespan was determined by the number of cycles until the change decreased by 0.3 i.

As a result, IM example (1) to (
In 3), it can be seen that a polyaniline thin film with a ratio of 11!2 (1) to (1) is obtained which is uniform in the 'dt polar direction, has high mechanical strength, and has an improved lifespan compared to the force.

(Effects of the Invention) As explained above, according to the method for producing a polyaniline thin film of the present invention, a sulfuric acid aqueous solution having a yield strength of 5 to 12N is used, rather than a sulfuric acid aqueous solution used in electrolytic oxidative polymerization. Thus, it is possible to produce a polyaniline thin film having excellent mechanical strength and a long life span.

In addition, the polyaniline thin film obtained by this method is
It is a demonstration of unconventional electrochromism.

[Brief explanation of drawings]

The drawing is a schematic diagram illustrating an example of a disintegration process used in the method for producing a polyaniline thin film of the present invention.

Claims (1)

[Claims] A method for producing a polyaniline thin film by electrolytically oxidizing and polymerizing aniline dissolved in an electrolyte solution, characterized in that an aqueous sulfuric acid solution having a concentration of 5 to 12 N is used as the electrolyte solution. How to make polyaniline thin film.