JP2906568B2 - Thin film deposition by micellar electrolysis - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application field] The present invention is to form a water-insoluble or hardly soluble organic or inorganic thin film on an electrode by an electrochemical method. For example, if an organic pigment is used as the above-mentioned substance, application to a color filter used for a liquid crystal display can be considered by coloring the electrodes R, G, and B. In addition, depending on the characteristics of the above substances, it can be used in various fields such as manufacturing into organic semiconductors, solar cells, electrophotographic photoreceptors, PHB memories, photoelectric conversion elements, gas sensors, biosensors, piezoelectric elements, dielectrics, superconductors, etc. Application development is conceivable.

[Conventional technology]

There has been no method for forming organic or inorganic particles that are water-insoluble or hardly soluble in water on an electrode in an aqueous solution.

As a method for forming an organic film by a wet method, an LB film and an electrolytic polymerization method are known. The LB film is a method in which molecules containing a hydrophilic group and a hydrophobic group are developed on the surface of water and collected on a substrate, and the film forming molecules are limited. Can not.

The electrolytic polymerization method is a method in which an organic substance is dissolved in a water-based or organic-based solvent and electrolysis is performed to deposit a polymerized film on an electrode. This is also limited to molecules having an unsaturated bond as organic substances so far, and inorganic films cannot be formed.

Recently, Saji et al. (J. Am. Clem. Soc., 109, 5881 (1987), Che
m, Lett 893 (1988)) report a micelle electrolysis method.

We have already found that it is possible to form other water-insoluble organic particles and water-insoluble inorganic particles using this micellar electrolysis method.

In these micellar electrolysis methods, after dispersing or solubilizing a water-insoluble or water-insoluble organic or inorganic substance in a surfactant micelle having a property of being charged by electrolysis,
The micelles are destroyed by electrolysis, and organic substances and inorganic substances are deposited on the electrodes.

[Problems to be solved by the invention]

The formation of a thin film by the micellar electrolysis method is a method of depositing fine particles in a solution (fine particles in micelles) on an electrode, and is an extremely low energy film forming method. For this reason, only the fine particles dispersed in the solution adhere to the electrode, and the adhesion is very weak, and even when the electrode is pulled up from the micelle solution, the film-forming portion is peeled off. There was a problem.

When the film is peeled off, only the upper layer of the film may be peeled off, and there is a problem in the smoothness of the formed micelle film.

If the micelle film is not smooth, the field of application can be limited. For example, when a color filter for a liquid crystal panel is manufactured using this film, if the film has large irregularities, problems such as poor alignment are likely to occur, and application as a color filter becomes impossible.

An object of the present invention is to obtain a uniform film having excellent smoothness by increasing the adhesion of the film forming section.

[Means for solving the problem]

The thin film formation method by the micelle electrolysis method of the present invention comprises a surfactant having a property of being charged by electrolysis, an organic or inorganic substance which is insoluble or poorly soluble in water, a supporting electrolyte, and an electrodeposition solution having a resin. In a micelle solution containing
The first electrolysis is performed at a micelle breakdown potential or higher and an electrodeposition potential or lower to form fine particles of water-insoluble or water-insoluble organic or inorganic substances on an electrode serving as a film-forming body. It is characterized in that a resin is formed between the fine particles formed on the electrode by performing electrolysis at a deposition potential or higher.

 Next, each step will be described in order.

The micelle solution of the present invention contains at least a surfactant, a supporting electrolyte, a water-insoluble or hardly water-soluble organic or inorganic substance, and components of an electrodeposition solution.

Any surfactant can be used as long as it can destroy micelles of the surfactant by electrolytic oxidation. For example, a metallocene group [M (C ₅ H ₅ ) ₂ : M = A surfactant having [Ti, V, Cr, Fe, Co, Ni, Ru, Os, Pd, etc.] corresponds to this.

One or more of these surfactants are dissolved in an aqueous solution to form micelles, and an organic or inorganic substance that is insoluble or hardly soluble in water is dispersed and suspended therein.

The surfactant concentration may be at least the critical micelle concentration, and the upper limit is not limited in some cases.

The supporting electrolyte is not limited and depends on the solution resistance.
Any concentration may be used as long as the IR drop can be ignored.

As a component of the electrodeposition solution, a resin prepolymer having a carboxyl group and neutralized with ammonia or an organic amine or the like, and a water-soluble melamine resin or a phenol resin as a crosslinking agent coexist.

A test electrode, a counter electrode, a micelle solution having the above composition,
By immersing the reference electrode and applying a potential equal to or higher than the micelle breakdown potential and equal to or lower than the electrodeposition potential of the prepolymer to the test electrode, an organic or inorganic film is formed on the test electrode.
By applying a potential higher than the electrodeposition potential for a short time, a polymer was formed between the fine particles of the organic or inorganic film.

By repeating this process, it was possible to form a smooth film with good adhesion composed of organic or inorganic fine particles on the electrode.

The film forming method is fundamentally different from the method of dispersing a pigment or the like in an electrodeposition solution to co-deposit the electrodeposition polymer and the pigment or the like in the ratio of the electrodeposition polymer to the pigment or the like. That is, the present invention is different in that the organic or inorganic fine particles ensure the adhesion of the film by so-called "soaking" of the electrodeposited polymer in the gap.

For this reason, when the amount of the pigment or the like per unit area is fixed, the film thickness of the present invention is always smaller than that of the electrodeposited film.

 Hereinafter, the present invention will be described in detail with reference to examples.

〔Example〕

ITO was formed as a transparent electrode by sputtering on a glass substrate having a diagonal width of 5 inches, and was further formed as a striped electrode having a width of 100 μm and a number of 300 by photolithography.

Next, micelle colloid aqueous solutions were prepared for the red, green, and blue dyes (organic pigments) having the compositions shown in Table 1, respectively.

Further, a mixture of acrylic acid and melamine at a ratio of 7: 3 to the three types of micellar colloid solutions was added in the solution at a ratio of 0.5 to 0.5.
It was added so as to contain wt%.

The electrodes were selectively energized during electrolysis so that the dye thin film had a repeating stripe pattern of blue, green, and red.
At the time of this electrolysis, first, the electrolysis potential was set to 0.4 V (VS. SCE), and the electrolysis time was adjusted so that each of the dye films became 0.3 μm. Next, set the electrolysis potential to 2.0V (VS.SCE),
The polymer was electrolyzed for a period of time soaked in the 0.3 μm dye film gap. By repeating this three times, a color filter having a stripe pattern in which the dye films each had a thickness of 1.0 μm was obtained. That is, the electrodeposition only increased the film thickness by 0.1 μm.

Thereafter, baking was performed at 180 ° C. for 30 minutes to obtain a color filter having good adhesion.

That is, even in the peeling test of the completed color filter using a scotch tape, the dye film was not peeled off at all.

Further, the color filter surface was extremely smooth, and there was no problem that the dye film was peeled off in the micelle colloid solution.

This color filter was made into a panel by flowing through a process of a liquid crystal panel, but there was no problem in the adhesion of the film, and no damage was caused by the rubbing treatment.

The driving characteristics of the liquid crystal were investigated using this panel.
No difference was recognized as compared with the conventional dye thin film alone. In addition, the durability reliability in an environment of 60 ° C. × 90% was evaluated, but no problem such as poor orientation occurred.

〔The invention's effect〕

As described above, as can be seen from the examples, the use of the present invention can improve the adhesion of the film by micellar electrolysis,
In addition, a flat film could be obtained. As a result, for example, when the present invention is applied to a color filter of a liquid crystal panel,
There was no difference compared to the case of the conventional dye film alone, and there was no problem such as poor alignment.

Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // G02F 1/1335 505 G02F 1/1335 505 (72) Inventor Kuniyoshi Matsui 3-5-5 Yamato, Suwa-shi, Nagano Pref. Seiko Epson Corporation In-company (58) Field surveyed (Int.Cl. ⁶ , DB name) C25D 9/00-9/08 C25D 13 / 02,13 / 04,13 / 10

Claims (2)

(57) [Claims] 1. A micelle solution containing a surfactant having a property of being charged by electrolysis, an organic or inorganic substance which is insoluble or hardly soluble in water, a supporting electrolyte, and an electrodeposition solution having a resin. A first electrolysis is performed at a micelle breakdown potential or higher and an electrodeposition potential or lower to form fine particles of water-insoluble or water-insoluble organic or inorganic substances on an electrode serving as a film-forming body. A thin film forming method by micellar electrolysis, wherein a resin is formed between fine particles formed on the electrode by performing electrolysis at a deposition potential or higher. 2. The method according to claim 1, wherein the first electrolysis and the second electrolysis are repeated at least twice to form a water-insoluble or water-insoluble organic or inorganic fine particle film. 2. A method for forming a thin film by the micelle electrolysis method according to 1.