JPS59217788A - Electrochromic material - Google Patents

Abstract

PURPOSE:An electrochromic material having clear multicolor display properties, stable repeating display characteristics, and high-speed response, containing a reaction product prepared by reacting a high polymer nonaromatic sulfonic acid with a high polymer viologen derivative in an aqueous solution. CONSTITUTION:The desired electrochromic material containing a high polymer ionic complex prepared by reacting (A) a high polymer nonaromatic sulfonic acid [e.g., ones shown by the formula I -formula III(X is cation; n is degree of polymerization; Y is 1-10)] with (B) a high polymer viologen derivative (e.g., poly-p-xylylene viologen, etc.) in an aqueous solution.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved electrochromic material that reversibly develops and fades color through redox reactions caused by voltage application.

In an electrochromic display (hereinafter abbreviated as ECD), by applying a voltage between a transparent display electrode and a counter electrode, an oxidation or reduction reaction occurs at the transparent display electrode to form a colored pattern, and when a reverse voltage is applied or A mechanism is utilized in which the colored pattern is erased by shorting between the transparent display electrode and the counter electrode.

ECDs, which develop and erase colors using this mechanism, are easier to see due to their bright color display without viewing angle dependence compared to liquid crystals, which have been traditionally used as light-receiving display elements.
It is attracting attention because it has many excellent features such as memory function, wide operating temperature range, and ease of making it larger.

The drawing shows a configuration diagram of a conventionally used general ECD element. In the figure, (1) is a glass substrate, (2)
is a transparent display electrode, (3) is an electrochromic material layer that develops and fades color, (4) is an electrolyte solution, (5) is a spacer,
(6) is a counter electrode.

That is, the transparent display electrodes fai (2
) and the counter electrode (6) with a spacer (5) interposed between them,
An electrochromic material layer (
3) to configure an ECD cell, and fill the space between the spacer (5) and the two electrodes with an electrolyte solution (4).
Create a D element. In ECD elements, the initial color-developing material is generally colorless or pale yellow, and the white color of the background plate is visually observed.
It is white or pale yellow. When a voltage of 1 to 2 V is applied between the transparent display electrode (2) as a negative electrode and the counter electrode (6), a color display corresponding to the electrochromic material is obtained, and the transparent display electrode (2) and the counter electrode (6) The color is erased by applying a voltage opposite to the above or short-circuiting the two electrodes.

Typical ECD materials that have been proposed in the past include organic compounds such as low-molecular-weight viologen derivatives (4,4'-bipyridine derivatives) and inorganic compounds such as tanges oxide and thene (WO3). .

Among these, organic compounds such as low-molecular-weight viologen derivatives can provide more vivid color display than inorganic compounds.
Moreover, it has the advantage that various colors can be selected by selecting the derivative.

However, E using a low molecular weight viologen derivative solution
Currently, CDs have not reached the level of practical use due to their short repeated display life, insufficient memory life, and insufficient response speed. As a method to solve the problems in ECD using molecular viologen derivatives, a polymer obtained from, for example, a polymerized viologen derivative and polystyrene, which has a tone group that changes color and disappears when voltage is applied, is coated on a transparent display electrode in advance. A method has been proposed. However, the types of colors that can be produced are relatively limited,
There is a need for a new material that can be colored in any desired color and has good stability in repeated display due to color development and fading.

This invention was made in order to eliminate the drawbacks of the conventional ones (4), and uses a material containing a product obtained by reacting a polymerized non-aromatic sulfonic acid and a polymerized viologen derivative in an aqueous solution. The object of the present invention is to obtain an electrochromic material having clear display with various color tones, more stable repeated display characteristics, and high-speed response.

Examples of the polymerized non-aromatic sulfonic acid used in this invention include those shown in the following formula.

OCR3 Here, X+ is a cation such as Na+, K+, Li+, but is not limited to the type of cation. Y represents a number from 0 to 1O, and n represents the degree of polymerization.

As the polymerized viologen, one represented by the following general formula is used, and for example, R is renviologen.

Br- The electrochromic material of the present invention can be easily obtained as a precipitate of a polymer ion complex by, for example, mixing an aqueous solution of the polymerized non-aromatic sulfonic acid and polymerized viologen.

To construct an ECD element using this polymer ion complex, the polymer ion complex is dissolved in a solvent and applied onto the transparent display electrode (2) shown in the drawing to form an electrochromic material layer (3). A 0ECD cell having a configuration similar to that shown in the drawings is prepared. The solvent used at this time is a mixed solvent of an organic solvent such as tetrahydrofuran, dioxane, dimethylformamide, or acetone, hydrochloric acid, and water. The electrochromic material coated on the transparent display electrode (2) in this manner becomes insoluble in general organic solvents and water after the solvent is dried and removed, forming a strong film.

Furthermore, in order to improve the color development efficiency and display contrast, an inorganic filler is mixed with a solution of polymer ion complex and applied to the transparent display. ii (
2) It is also effective to form a composite film thereon. As the inorganic filler, tin oxide, indium oxide, zinc oxide, titanium oxide, etc., and those made conductive by heat treatment, mixing with a different element, or surface treatment can be used.

As the electrolyte solution filled into the cell, the supporting electrolyte is dissolved in water or an organic solvent such as dimethylformamide, acetonitrile, propylene carbonate, or a mixed solvent of water and an organic solvent at a concentration of 0.01 to 5 mol/l. used. Examples of supporting electrolytes include lithium chloride, potassium chloride, sodium chloride, potassium bromide, potassium sulfate, sulfuric acid(7), ferrous iron, potassium perchlorate, lithium perchlorate, tetraethylammonium perchlorate, potassium borofluoride. , potassium phosphate, potassium acetate, etc. are used.

In the ECD element constructed in this manner, the color-developing material is initially colorless or pale yellow, and the white color of the background plate is visually observed and is white or pale yellow. Further, when an inorganic filler is used, the color of the inorganic filler can be visually observed.

As with the conventional ECD, if a voltage of 1 to 2 V is applied between the transparent display electrode (2) side as a negative electrode and the counter electrode (6), a clear display can be obtained. The displayed color tone mainly depends on the type of polymerized viologen (4) used, but also changes depending on the type of polymerized non-aromatic sulfonic acid. For example, when poly 1゜2-butene-4-sulfonic acid (Y = 1) in (3) is used, the color is blue-purple, but (
2) poly-2-sulfonic acid ethyl vinyl ether (Y
=1) and poly-2-acrylamido-2-methyl-1-propanesulfonic acid of (1) result in a display color close to red. This is because when the polymerized viologen is reduced by voltage application (A8) and becomes colored, the color tone changes due to interaction with the polar groups of the polymerized non-aromatic sulfonic acid. The type of polymerized non-aromatic sulfonic acid can be selected depending on the purpose.

From the state where I'C is displayed in this way, the transparent display electrode (2
) by applying a positive voltage or by short-circuiting the transparent display electrode (2) and the counter electrode (6), the color is quickly erased and the original state returns to zero.

This invention will be explained below with reference to examples, but the invention is not limited thereto. 5 Example 1 Sodium poly-2-acrylamide-2-methyl-1-propanesulfonate 4,589 was dissolved in 100 ml of water. do. Poly P-xylyl viologen 4.2f 1
00 ml and gradually added dropwise to the sulfonic acid solution while stirring. The precipitate was isolated by centrifugation and dried to obtain a hatsumode-like polymer ion complex.This polymer ion complex 1f was mixed with dioxane 10m/m, water 1m6s concentrated hydrochloric acid 10mJ? It was dissolved in a mixed solvent of and applied on a transparent display electrode so that the dry film thickness was 1 μm.

This is used to construct an ECD cell, and 0.0% of potassium sulfate is used.
An ECD device was prepared by injecting an 8 mol/l aqueous solution.

1.2 between the transparent display electrode and the opposite wLrU
When a voltage of V was applied, a current was observed indicating that a reduction reaction was occurring, and at the same time, a reddish-purple display with good contrast was obtained. By applying a voltage in the opposite direction, it quickly returns to its original white color, and this cycle of coloring and decoloring is performed stably.

Example 2 A polymer ion complex was synthesized in the same manner as in Example 1, except that poly-2-sulfonic acid ethyl vinyl ether sodium salt was used as the polymerized non-aromatic sulfonic acid, and an ECD device was produced. When a voltage of 1.2 V was applied with the transparent display electrode set as negative, a reddish-purple display with good contrast was obtained. The color was quickly decolored by applying a voltage in the opposite direction, and the repetition of coloring and decoloring of the kernels was performed stably.

Example 8 - Example 1 except that sodium poly-1°2-butene-4-sulfonate is used as the polymerized non-aromatic sulfonic acid.
A polymer ion complex was synthesized in the same manner.

After adding and mixing 10 g of conductive fine powder of tin oxide to a solution of 1 g of this polymer ion complex, the mixture was coated on a Taomei display electrode to prepare an ECD element. By applying a voltage of IV with the transparent display electrode set as negative, a clear display of blue-purple color against a white background was obtained. The color was quickly decolored by applying a voltage in the opposite direction, and the repetition of coloring and decoloring was performed stably.

As explained above, the present invention uses a substance obtained by reacting a polymerized non-aromatic sulfonic acid and a polymerized viologen derivative in an aqueous solution, thereby providing a clear display with various color tones, It has become possible to obtain an electrochromic material that has more stable repeat display characteristics and high-speed response.

[Brief explanation of the drawing]

The drawing is a configuration diagram of a general ECD element. In the figure, (1) is a glass substrate, (2) is a transparent display turtle [% (3) is an electrochromic material! , (4) is an electrolyte solution, (5) is a spacer, and (6) is a counter electrode. Agent Masuo Oiwa

Claims (3)

[Claims] (1) An electrochromic material containing a material obtained by reacting a polymerized non-aromatic sulfonic acid and a polymerized viologen derivative in an aqueous solution. (2) Electrochromic material 1° according to claim 1 containing an inorganic filler (3) The electrochromic material according to claim 1, wherein the polymerized non-aromatic sulfonic acid is at least one of those represented by the following general formula. Winter Y: 1-10