JPH01298602A - Manufacture of coated body and film - Google Patents

Abstract

PURPOSE:To facilitate the control of the film thickness and manufacture of a film made of an organic electric charge transfer(CT) complex, which is free of pinholes and excellent in electric characteristics, and a coated body coated with the film by forming a polymer film on the surface of an electron donor medium and thereafter forming a CT complex therein. CONSTITUTION:A copper plate (transition metal base body) 1 with a predetermined thickness is cleaned with sulfuric acid water in a predetermined concentration so as to remove oxide on the surface thereof, followed by a polymer coating processing to obtain a polymer coating copper plate (polymer film). A predetermined quantity of 7,7,8,8-tetracyanodimethane TCNQ is added in acetonitrile while performing bubbling with nitrogen so as to adjust the saturated solution of TCNQ. The polymer film is dipped in the solution and left for a predetermined time while slowly agitating the whole of the solution, thereby generating organic CT complex on the polymer film. The copper plates with the surfaces coated with the organic complex are laminated, and on the obtained film 2 including the organic CT complex, Al is deposited so as to form an electrode 3.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for producing a film containing an organic charge transfer complex and a coating coated with the film, and more specifically,
A method for easily producing a film containing an organic charge transfer complex that is highly flexible, free of pinholes, and has excellent electrical properties such as a switching function and a memory function, and a covering covered with the film. .

(Prior art) 7.7,8.8-tetracyanoquinodimethane (hereinafter referred to as T
Organic charge transfer complexes (hereinafter referred to as acT complexes) using CNQ) and similar compounds thereof as electron acceptors have been actively researched as organic semiconductors. One of those studies is 17. S, pOteI! I
U.S. Pat. No. 4,371,883 to Ber et al.
As disclosed in Nos. 4,507,672 and 4,652,894, when an electric field equal to or higher than a threshold value is applied in the film thickness direction to a thin film grown on a substrate, the above-mentioned CT complex is grown on a substrate. The impedance in the thickness direction changes from a relatively high impedance to a relatively low impedance, and depending on the type of complex compound, the state can be memorized, so the possibility of it as a new memory material has been proposed. Furthermore, as disclosed in Japanese Patent Publication No. 60-500587, it is possible to achieve such a switching effect by light irradiation, so this is attracting attention as a new optical memory material.

Moreover, it is known that this organic CT complex thin film not only changes its impedance, but also the color of the thin film itself changes significantly.

For example, Japanese Journal of
Applied Physics+VO1,25,N(
L4.1986. L, 341-L, 342, by irradiating an organic CT complex thin film prepared on a glass plate with a laser beam, it changes reversibly from dark green to translucent light green, and at the same time changes that state. It is possible to hold.

As described above, the 99-enriched CT ti body membrane is a novel switching memory material, and at the same time, it is a material that can be applied to electrochromism and photochromism devices.

By the way, several methods have been conventionally proposed as methods for producing these organic CT complexes.

The first method is to immerse a substrate such as copper or silver in a solution in which an organic electron acceptor is dissolved, and to form aCT on the surface of the substrate due to the reaction between the organic electron acceptor and the substrate. This is an organic electron acceptor solution immersion method used to grow thin films of complexes.

The second method is to vacuum-deposit an organic electron acceptor on the substrate while heating it, and then apply organic CT to the surface of the substrate.
This is a solid-phase deposition diffusion method that grows a thin film of the complex.

The third method is to use an electrically insulating substrate (for example, a glass substrate)
This is a thermal vapor deposition method in which both an electron donor such as copper or silver and an organic electron acceptor are deposited on top of the material, and then the entire structure is heated to a predetermined temperature to grow a thin film of an organic CT complex. .

The fourth method is a resin dispersion method in which a pre-synthesized IIICT complex is dispersed in a predetermined resin solution, the resulting dispersion is applied onto a substrate to a suitable thickness, and then dried.

(Problem to be solved by the invention) However, the above construction methods have advantages and disadvantages.

First, in the case of the first method, the film thickness of the organic CT complex thin film is
Easily controlled by changing the immersion time of the substrate.
However, the thin film obtained is brittle, lacks flexibility, and is prone to pinholes. In the case of the second and third methods, the obtained thin films have excellent switching properties, but the manufacturing equipment is large-scale, film thickness control is not easy, and it is difficult to form films over large areas. I have a problem with that. Furthermore, the fourth
The method described above has the advantage that it is easy to form a film over a large area, but there is a problem in that the electrical properties of the obtained thin film, particularly the electrical conductivity, are low.

As described above, conventionally known methods have advantages and disadvantages. The present invention solves these problems, has easy film thickness control, is highly flexible, does not generate pinholes, and
Moreover, it is an object of the present invention to provide a method for easily producing a film of an organic CT complex having excellent electrical properties and a covering covered with the film.

(Means and effects for solving the problem) As a result of intensive research to achieve the above object, the present inventors formed a polymer film as described below on the surface of a substrate that is an electron donor, and then The inventors discovered that the above object can be achieved by forming an organic CTtf body therein, and developed the method of the present invention.

That is, the method for producing a coated body coated with a charge transfer complex-containing film of the present invention includes the steps of: coating the surface of a substrate at least the surface of which is made of a transition metal with a polymer (first step); is immersed in a solution containing an organic electron acceptor that is electrochemically neutral and forms a charge transfer complex with the transition metal (second step)
Further, the method for producing the film is characterized in that, following the above step, the method further comprises a step of peeling off the coated polymer from the substrate. This is a step of coating the surface with a polymer to be described later to form a film of the polymer.

Here, the surface of the substrate is composed of a transition metal. This transition metal may be any metal as long as it is capable of forming a charge transfer complex (hereinafter referred to as CTjf body) with the organic electron acceptor described below, such as copper, cobalt, nickel, iron, and manganese. etc., but the reactivity with the organic electron acceptor used, the obtained electron
From the viewpoint of Tt=body stability, switching properties of the obtained organic C719 body, and its memory properties, it is particularly desirable to use copper, silver, or both. In addition, as a substrate, metal foil, metal plate, metal block,
In addition to materials consisting of a single metal itself such as a metal piece, it may also be a composite material such as one in which a layer of the above-mentioned transition metal is formed on the surface of an insulator such as a copper-clad laminate by means such as vapor deposition or plating. .

The polymer used to coat this substrate surface is
Appropriate electrical insulation and flexibility without significantly interfering with the CT complexing reaction between an organic electron acceptor and a transition metal, which will be described later.
It has moldability, and also has the property of not dissolving or swelling in the solvent used as a solution for the organic electron acceptor stand used in the subsequent second step of CT complex formation. It is necessary to be present.

Preferably, such a polymer contains one or more of polyester, polyamide, and polyester amide as a main component.

In that case, these polymers can be prepared by dissolving the polymer in m-cresol so that the polymer concentration is 0.25 glo
, 25 d The reduced viscosity (7
7s1)/C) is 0.2 to 1. It is preferable that the degree of polymerization is Odf/g.

If a polymer with a reduced viscosity of less than 0.2 df/g is used, the cohesive force of the polymer is weak, resulting in poor flexibility of the formed film and insufficient adhesion to the substrate surface. Furthermore, in the second step described below, the polymer dissolves in the solvent or swells due to the solvent, leading to the inconvenience of further deformation of the film. /g, the wetting with the surface transition metal becomes poor, leading to a decrease in adhesion, and in the second step, the permeation diffusion rate of the organic electron acceptor into the polymer decreases, The ability to form the desired organic CT complex is reduced.

A coating method is usually employed to coat the surface of the substrate with a polymer. In this case, coating methods include a solution prepared by dissolving the polymer in a solvent such as methylene chloride, or a method in which the dissolved polymer is directly coated on the substrate surface, as well as a generally known method such as a roll coater or a bar coater. method can be applied. At this time, by arbitrarily changing the amount of polymer and polymer concentration, it is possible to control the thickness of the formed polymer film to an arbitrary thickness.

In this case, the reaction rate during the reaction between the transition metal and the organic electron acceptor in the second step, and the obtained MA
c'r jf body gold-containing film switching characteristics,
And from the point of view of its memory characteristics, 0.01
It is desirable that the thickness be 10 μm, preferably 0.1 to 10 μm.

If the polymer film formed in the first step is too thick, the rate of permeation and diffusion of the organic electron acceptor into the polymer film in the second step will decrease, and the organic carbon in the film will decrease.
The ability to form T-complexes is reduced. Furthermore, if the thickness of the polymer film is too thin, there is a strong tendency for pinholes to occur.

After the surface of the substrate is coated with the polymer, the entire surface is dried if necessary.

The second step is a step in which an organic CT complex is generated in the polymer film formed in the first step.

In this step, the polymer-coated substrate produced in the first step is immersed in an electrochemically neutral solution containing an electron acceptor as described below.

As a result, the organic electron acceptor in the solution permeates and diffuses into the polymer film, causes a CT complex reaction with the transition metal constituting the substrate surface, and forms a CT complex within the polymer film. Ru.

As the organic electron acceptor used in the method of the present invention, compounds having a cyanomethylene functional group, particularly compounds having a quinone or aphthoquinone skeleton and a dicyanomethylene group are suitable. Among these, TCNQ is particularly suitable because it has strong CT s = body shape ability, excellent electrical properties such as switching of the resulting film, and excellent stability of the complex.

The solution according to the present invention is prepared by dissolving these organic electron acceptors in a polar aprotic medium such as acetonitrile, dioxane, N1N-dimethylformamide, dimethyl sulfoxide, hexamethylphosphoramide, methyl ethyl ketone, etc. Ru.

The concentration of the organic electron acceptor in this solution is not particularly limited, but is suitably 0.01 parts by weight to saturation concentration, preferably 0.1 parts by weight to saturation concentration, per 100 parts by weight of the solvent.

Organic CT complexes can be formed at temperatures between 10 and 30°C, however, when the organic electron acceptor used and the i! ! Depending on the combination with the transfer metal, the CT complexation reaction may proceed rapidly, making it difficult to obtain a dense and uniform target film. In such a case, the solution used may be cooled if necessary.

On the other hand, if the complexation reaction is slow and it takes a long time to form an organic CT complex-containing film, the solution can be heated as necessary.

The required immersion time of the polymer-coated substrate in the solution largely depends on the combination of organic electron acceptor and transition metal used or the thickness of the polymer film, but in general, if the immersion time is too short, CT Rt Since the incorporation reaction has not progressed sufficiently, the electrical conductivity of the obtained organic CTtiF body-containing film becomes low, and sufficient switching characteristics and memory characteristics thereof cannot be obtained. On the other hand, if the polymer film is immersed for too long, there is a risk that the polymer film will deform and swell, but this will have little effect on the switching characteristics and memory characteristics.

However, with the growth of the CT complex, the adhesion between the polymer film and the substrate gradually decreases;
! cTt=for the purpose of producing a coating of body-containing film;
When adhesion between the film and the substrate is required, it should be avoided to extend the immersion time longer than necessary.

Preferred soaking times are usually 10 seconds to 1 hour.

The presence or absence of the formation of QICTti bodies can be investigated by measuring electrical properties, but a simple method is, for example, if the TCNQ solution is pale yellow, while the organic CT complex is black. It can also be determined by the change in color of the film.

Thus, a polymer film containing the organic CT complex is formed on the surface of the substrate. Wash this film and
By drying, it can be put to practical use.

The cleaning treatment is usually carried out using a solvent with low dissolving power for the polymer used for film formation, such as an alcohol-based ig agent such as methyl alcohol or ethyl alcohol, Hensen,
It is appropriate to use a hydrocarbon solvent such as toluene or hexane, or water. Also, drying can be done from room temperature to 1
At a temperature of about 00'C, at normal pressure or reduced pressure, for 5 minutes to 1 hour.
It is appropriate to do this for about an hour.

Further, the production of the nCT complex-containing film in the present invention is carried out by peeling off the organic CT complex-containing film from the coating. This organic c'rtf-containing film has a
The immersion time for forming the body is 1.5 to 10 times that for producing the coating, or the temperature of the organic electron acceptor solution is 5 to 50'C higher than the temperature at the time of producing the coating. By increasing the degree of separation, it can be easily peeled off from the substrate. The organic CT complex-containing film produced in this way can be used in the applications described above with respect to the coating, such as by being attached to other suitable substrates.

(Embodiments of the Invention) Synthesis Example 1 45 mol% dimethyl terephthalate, 200 mol% 1,4-butanediol, and 0.02 mol% t-butyl titanate as a catalyst were blended at a temperature of 140 to 190' in a nitrogen stream. The transesterification reaction proceeded with C.

After completion of the transesterification reaction, 15 mol% of isophthalic acid and 40 mol% of adipic acid were added to the obtained esterified product,
After carrying out the esterification reaction at a temperature of 190 to 210 °C,
Raise the temperature and reduce the pressure at the same time, 5 jig, 210-270
The polymerization proceeded at °C, and the reduced viscosity of the polymer was 0.65 dA.
/g, the reaction was terminated. A polyester resin (referred to as Polymer 1) consisting of 45 molar equivalents of terephthalic acid residues, 15 molar equivalents of isophthalic acid residues, 40 molar equivalents of adipic acid residues, and 100 molar equivalents of 1,4-butanediol residues was obtained. .

Synthesis Example 2 200g (100 parts by weight) of the above Polymer 1 was collected and melted in an oil bath at 240°C, and 60g (30 parts by weight) of Nylon 11 (manufactured by Nippon Rilsan ■) and ethylene glycol were added thereto. Add 6g (triplicate) and react under reflux for 4 hours under a nitrogen stream, and then add 5+nm1
The reaction was allowed to proceed for 1 hour under a vacuum of 1 g. Reduced viscosity 0.85
dN/g polyesteramide resin (polymer 2
) was obtained.

Synthesis Example 3 The same transesterification and polymerization reactions as in Synthesis Example 1 were carried out, and the reaction was terminated when the reduced viscosity of the obtained polymer reached 0.18dN7g. A polyester resin (referred to as Polymer 3) having the same composition as Polymer 1 was obtained.

Synthesis Example 4 The same transesterification and polymerization reactions as in Synthesis Example 1 were carried out, and the reaction was terminated when the reduced viscosity of the obtained polymer reached 1.20 df/g. A polyester resin having the same composition as Polymer 1 (referred to as Polymer 4) was obtained.

Example 1 A copper plate (20 mm x 50 ai) with a thickness of 100 μm was immersed in a 5% by weight sulfuric acid aqueous solution to remove surface oxides, and then washed three times with pure water and dried at room temperature.

A 3% by weight methylene chloride solution of Polymer 1 was prepared, and the copper plate was immersed therein, and then the copper plate was gradually pulled up and dried at 40°C for 5 minutes while keeping it horizontal. Further under reduced pressure (
It was dried at room temperature for 1 hour under several mmHg). A polymer-coated copper plate (polymer film thickness: 2 μm) was obtained.

7.7.8.8-Tetracyanoquinodimethane (manufactured by Nippon Carlint, industrial use) 1.0 g was mixed with acetonitrile (special grade reagent) 50aj! A saturated solution of TCNQ was prepared by bubbling nitrogen gas into the solution.

A polymer-coated copper plate was immersed in this TCNQ saturated solution at room temperature, and the whole was left to stand for 5 minutes while being gently stirred to grow an organic CT complex in the polymer film.

Next, the copper plate was taken out, washed twice with acetonitrile and twice with methyl alcohol (reagent grade), air-dried at room temperature, and further dried under reduced pressure (several mm mm 1 liter for 2 hours). An organic CT complex-containing film was formed on the surface. This film did not show any pinholes, was as flexible as the film before forming the organic CT complex, and could be easily handled.

Using the obtained copper plate, a sandwich type cell as shown in FIG. 1 was manufactured. That is, on the acTti body-containing film 2 covering the surface of the copper plate 1, aluminum was vacuum deposited (deposition area: 28 dm+'') to form the electrode 3.

In this sample cell, 0.01V is applied to the copper electrode (copper plate l).
The following cycle of voltage was applied at a sweep rate of /sec, and the current-voltage characteristics at that time were measured.

Voltage application cycle Nα1 0 → −1O No, 2 −10 → 0 NL13 0 → +l0 k4 +10 − −1O Nα5 −10 → +10 (Nα4 from 2
4 hours later) The results are shown in FIG. 2 and Table 1. As is clear from Fig. 2, in the initial state (off state, i.e., high resistance state), the state is maintained from 0 to -10V and from 0 to 5V, and the sweep voltage is set to the threshold value (vth ), the resistance value of the film decreases rapidly (
Line 3) shows a typical switching phenomenon where the current value increases. Once this resistance state is reached, this state is maintained and the resistance state becomes low in both directions within the range of -10 to IOV (line 4). Moreover, this state of resistance is
Almost completely retained even after 24 hours (line 5)
).

Example 2 Example 1 except that a glass epoxy copper-clad laminate (manufactured by Matsushita Electric Works, R-1701) was used instead of the copper plate, and a 1% by weight methylene chloride solution of Polymer 2 was used as the polymer solution. In the same manner as above, a polymer film having a thickness of about 0.5 μm was formed on the surface of the N-laminated plate. This was then immersed in the same TCNQ saturated solution as in Example 1 for 10 minutes.

As in Example 1, a flexible organic CT19-containing film was obtained. The switching characteristics and memory characteristics of this film were measured in the same manner as in Example 1. The results are shown in Table 1. As can be seen, the switching characteristics and memory characteristics were changed by more than four orders of magnitude in electrical conductivity.

Example 3 Silver plate (20m x 50I+11, thickness 10
Copolymerized polyamide resin: Canny Bond S-200 (reduced viscosity 0.12
A polymer film having a thickness of about 1 μm was formed on the surface of a silver plate in the same manner as in Example 1, except that a 2% by weight solution of methylene chloride (dl/g, manufactured by Toagosei Chemical Industry Co., Ltd.) was used. Then, in the same manner as in Example 1, this was immersed in a 0.4% solution of TCNQ in methyl ethyl ketone for 10 minutes.
An organic CT complex-containing film was formed. In addition, the switching characteristics and memory characteristics were similarly measured.

The results are shown in Table 1.

Example 4 The same procedure as in Example 1 was carried out, except that Polymer 1 was melted at 150°C and stretched using a hot press to form a polymer film with a thickness of about 0.5 μm on the surface of the copper plate. A flexible organic CT complex-containing film was created. Similarly, the switching characteristics and memory characteristics of this film were measured. The results are shown in Table 1.

Example 5 Under the same conditions as Example 1, a polymer-coated copper plate was coated with TCNQ.
Saturation? 8'm for 5 minutes to grow an organic CT complex in the polymer film.

Thereafter, the copper plate was left at 40°C for 25 minutes without being removed from the solution.

The polymer thin film began to peel off from the edges and could be easily peeled off with tweezers. Washing and drying were performed in the same manner as in Example 1 to obtain a CT complex-containing film.

(The following is a blank space) Comparative Reference Example 1 A polymer film with a thickness of about 1 μm was formed on the surface of a copper plate in the same manner as in Example 1, except that a 2% by weight methylene chloride solution of Polymer 3 was used as the polymer solution.

This was then immersed in a TCNQ saturated solution in the same manner as in Example 1. Although the CT complexation reaction progressed, the polymer swelled and
Deformed. Furthermore, an attempt was made to measure the switching characteristics, but due to the generation of pinholes, conduction occurred between the two electrodes, making it impossible to measure.

Comparative Reference Example 2 A polymer film with a thickness of about 2 μm was formed on the surface of a copper plate in the same manner as in Example 1, except that a 2% by weight methylene chloride solution of Polymer 4 was used as the polymer solution.

This was then immersed in a TCNQ saturated solution in the same manner as in Example 1. Even after immersion for 1 hour, it was found that the color of the film did not change much and the CT complexation reaction did not proceed, and the desired organic CT complex-containing film could not be obtained.

Comparison Reference Example 3 Polymer? As a solution, polymethyl methacrylate) (
PMMA, reagent manufactured by Aldrich, number average molecular weight 12
A polymer film having a thickness of approximately 1 μm was formed on the surface of a copper plate in the same manner as in Example 1, except that a 2% by weight methylene chloride solution having a reduced viscosity of 0.000 and reduced viscosity of 0.73 dJ2/g) was used. This was then immersed in a TCQN saturated solution in the same manner as in Example 1. Although the CT complexation reaction progressed, the polymer swelled and deformed.

Furthermore, when I tried to measure its switching characteristics,
Due to the occurrence of binho/lz, conduction was established between both electrodes, making measurement impossible.

(Effects of the Invention) As is clear from the above explanation, the method of the present invention provides an organic CT complex-containing film that is highly flexible, has no pinholes, and has good switching and memory properties, and a film containing the organic CT complex. The coated body can be easily manufactured by scratching, and the film thickness can also be easily controlled, making it an ideal industrial method for manufacturing new functional thin films, switching devices, and memory devices. The value is great.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a sandwich type cell incorporating a film produced by the method of the present invention, and FIG. 2 is a current-voltage characteristic diagram of the film according to the present invention. DESCRIPTION OF SYMBOLS 1... Copper plate (transition metal base), 2... Organic CT complex containing film, 3... Aluminum electrode. Applicant Toagosei Chemical Industry Co., Ltd. Agent Patent Attorney Kanji Nagado

Claims (2)

[Claims] (1) Coating the surface of a substrate, at least the surface of which is made of a transition metal; and coating the polymer-coated substrate with an organic electron acceptor that is electrochemically neutral and forms a charge transfer complex with the transition metal. A method for producing a coated body coated with an organic charge transfer complex-containing film, the method comprising: immersing the body in a solution containing the organic charge transfer complex. (2) coating the surface of a substrate, at least the surface of which is made of a transition metal; and coating the polymer-coated substrate with an organic electron acceptor that is electrochemically neutral and forms a charge transfer complex with the transition metal; A method for producing an organic charge transfer complex-containing film, comprising the steps of: immersing the film in a solution containing the organic charge transfer complex; and peeling off the coated polymer from the substrate.