JPH11256164A - Gel-like substance and display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a gel-like substance consisting main by of a liquid crystalline compound originally having fluidity and a gel-like substance substantially lost its fluidity, particularly that exhibiting liquid crystallinity and provide a display device containing the gel-like substance exhibiting the liquid crystallinity as a light-modulating layer. SOLUTION: This gel-like substance, especially that having liquid crystallinity comprises a liquid crystalline compound and a gelling agent having an organic group containing a skeleton represented by the formula (R is hydrogen atom or an organic group). The display device is obtained by using this gel-like substance as a light-modulating layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gel-like substance mainly containing a liquid crystal compound having fluidity and having substantially no fluidity of the liquid-crystal compound, and more particularly to a gel-like substance exhibiting liquid crystallinity. . Furthermore, the present invention also relates to a display device using the above-mentioned liquid crystalline gel material as a light control layer.

[0002]

2. Description of the Related Art It is well known that liquid and fluid liquid crystal molecules are used for liquid crystal displays. On the other hand, as a method for treating spilled crude oil, domestic waste oil and the like, there is known a treatment method in which an oil gelling agent is added to these oils to solidify them in a jelly state. However, these prior arts do not disclose or suggest the present invention.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a gel-like substance which contains a liquid crystalline compound having fluidity as a main component, and which substantially loses its fluidity, and particularly exhibits a liquid crystalline property. It is to provide a gel-like substance. Another object of the present invention is to provide a display device in which a liquid crystal gel material is used as a light control layer.

[0004]

According to the present invention, the following objects of the present invention are achieved by providing the following gel-like substances and display devices (1) to (3). (1) (A) a liquid crystalline compound and (B) a compound represented by the following formula (I)

[0005]

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A gel-like substance comprising a gelling agent having an organic group having a divalent skeleton represented by the formula (wherein R is a hydrogen atom or an organic group). (2) The gel substance according to the above (1), which exhibits liquid crystallinity. (3) A display device, wherein the liquid crystalline gel-like substance according to (2) is used for a light control layer. Hereinafter, the present invention will be described in detail, whereby the object of the present invention,
Benefits and effects will become apparent.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The gel substance of the present invention is mainly composed of a liquid (fluid) (A) liquid crystal compound (liquid crystal molecule) used for a liquid crystal display. Due to the action of (B) a gelling agent having an organic group containing a divalent skeleton represented by the above formula (I) (hereinafter also referred to as “(B) amino acid-based gelling agent”), (A) a liquid crystal The fluidity of the active compound has disappeared, and the gel has been gelled as a whole. Then, the gel substance can be in an optically anisotropic liquid crystal state in a specific temperature range. The (B) amino acid-based gelling agent forms (a) a giant fibrous aggregate by intermolecular interaction such as hydrogen bonding, and (b) the giant fibrous aggregate is further interacted by van der Waals force or the like. To form a network structure by three-dimensional formation, and (c) acts so as to incorporate the (A) liquid crystal compound into the network structure. It is presumed that the liquid crystal compound lost its fluidity and became a gel.

As the liquid crystal compound (A) which is a component of the gel substance of the present invention, liquid crystal molecules conventionally used for liquid crystal displays can be used.
For details, see “Liquid Crystal Device Handbook” edited by the 142nd Committee of the Japan Society for the Promotion of Science (1989 first edition);
2, p715-722, various liquid crystal molecules or ferroelectric liquid crystal molecules such as biphenyl, phenylcyclohexane, phenylpyrimidine, cyclohexylcyclohexane, etc. exhibiting a nematic or smectic phase, antiferroelectric liquid crystal molecules, or A mixture of these liquid crystal molecules can be mentioned. Specifically, the following formula (A-1),
Represented by (A-2), (A-3) and (A-4), each of which is 4-n-pentyl-4′-cyanobiphenyl (A-
1), 4-n-heptyloxy-4'-cyanobiphenyl (A-2), p-methoxybenzylidene-p'-butylaniline (A-3) and 4-n-decanoxy-4'-
A liquid crystal molecule named cyanobiphenyl (A-4) can be mentioned.

[0009]

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The gelling agent (B), which is another component of the gel substance of the present invention, comprises one molecule of an organic group having a divalent skeleton represented by the above formula (I) capable of forming an intermolecular hydrogen bond. One or more, preferably 1 to 10, more preferably 1
It has 4 to 4 and is called an amino acid-based gelling agent. The organic group containing a skeleton represented by the above formula (I) is preferably a compound represented by the following formula (II)

[0011]

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The structure shown in FIG. R in the formulas (I) and (II) is a hydrogen atom or an organic group. The organic group is not particularly limited, but is preferably an alkyl group or an aryl group, more preferably a lower alkyl group having 1 to 6 carbon atoms, and particularly preferably a branched chain saturated carbon having 3 to 6 carbon atoms. A hydrogen group such as an isopropyl group, an isobutyl group, an s-butyl group; Specific examples of the organic group are described below, including the preferred examples described above.

[0013]

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The amino acid-based gelling agent (B) is, apart from the divalent organic group represented by the above formula (1), an alkyl group or alkylene group having 3 or more carbon atoms, preferably 4 to 30 carbon atoms.
Aryl, arylene, arylalkyl (eg benzyl) or benzyloxycarbonyl (C ₆
It is preferred to have the H ₅ CH ₂ OCO- group). Particularly preferably, C6-C20 is also an alkyl group or an alkylene group. These may be used alone or in combination of two or more.

(B) The amino acid-based gelling agent preferably has a molecular weight of 2,000 or less, more preferably 150 to 100.
0. Further, (B) the amino acid-based gelling agent preferably has a chiral structure. Preferred specific examples of the amino acid-based gelling agent (B) include ZL-isoleucine octadecylamide represented by the following formula (B-1) and dodeca of ZL-valine represented by the following formula (B-2). Examples thereof include methylene diamide and the following formulas (B-3) to (B-6).

[0016]

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Other examples include alanine, asparagine, aspartic acid, cysteine, glutamic acid, phenylalanine, glycine, histidine, lysine, leucine, methionine, proline, glutamine, arginine,
Α of serine, threonine, tryptophan, tyrosine, etc.
A gelling agent having one or more amino acid residues;

The amount of (A) the amino acid-based gelling agent required for gelling the (A) liquid crystal compound depends on the type of these compounds, but is based on the total amount of (A) the liquid crystal compound. And preferably 0.01 to 20 mol%, more preferably 0.1 to 10 mol%.

As a method for obtaining a gel-like substance from (A) a liquid crystalline compound and (B) an amino acid-based gelling agent, a method of heating these into a uniform isotropic solution, followed by cooling. However, it is not limited to this method.
By employing this method, an optically anisotropic, ie, liquid crystalline, gel-like substance can be obtained in a specific temperature range.

As specifically shown in Example 1 and FIG. 1 described later, for example, (A) a liquid crystal compound represented by the formula (A-1) is used as a liquid crystal compound, and (B) an amino acid-based gel When the compound represented by the formula (B-1) is used as the agent and the molar fraction of the amino acid-based gelling agent (B) is 1 mol%, the isotropic homogeneous mixed solution is cooled to obtain 45%. An isotropic gel-like substance is obtained between 35 ° C. and 35 ° C., and by further cooling, a liquid-crystalline gel-like substance (liquid crystal gel) showing optical anisotropy between 35 ° C. and −18 ° C.
Can be obtained. The liquid crystalline gel substance returns to the isotropic solution via the isotropic gel substance by reheating, and the same phenomenon occurs again when recooled. Thus, the gel substance of the present invention is thermally reversible.

Further, the liquid crystalline gel material of the present invention changes its orientation in accordance with the change of the electric field strength and shows a clear electric field response. Accordingly, the liquid crystalline gel material of the present invention can be used as a liquid crystal in a light control layer of a liquid crystal display device.

The liquid crystal device of the present invention includes a light control layer containing the above-mentioned liquid crystal gel. And the structure of the liquid crystal device of the present invention can be the same as a liquid crystal device having a conventional polymer-dispersed liquid crystal as a light control layer, except for the material of the light control layer,
You are not limited to that structure. The light control layer is usually provided with at least one of the electrodes having an electrode layer supported between two transparent substrates. Here, a spacer for maintaining a space may be interposed between the two substrates, similarly to a known liquid crystal device. The substrate may be a rigid material such as glass or metal, or a flexible material such as a plastic film. The two substrates face each other at an appropriate interval.
In addition, at least one of the two substrates has transparency. Here, “transparency” does not mean complete transparency, but has transparency according to the intended use of the liquid crystal device. It should just be. If the liquid crystal device of the present invention is to act on light passing from one side of the device to the other, both substrates need to be fairly transparent. Further, a transparent or opaque electrode may be provided on the entire surface or a part of the substrate depending on the purpose. When the liquid crystal device of the present invention is used for a display device of a computer terminal, a display device of a projection, or the like, it is preferable to provide an active element on an electrode layer on a support.

The thickness of the light control layer is appropriately selected according to the purpose of use of the liquid crystal device of the present invention. However, when the light control layer becomes opaque due to light scattering, the light scattering is substantially reduced. In order to obtain a sufficient contrast with that when the film becomes transparent, the range is preferably 1 to 50 μm, and 5 to 25 μm.
The range of m is particularly preferred.

The light modulating layer of the liquid crystal device of the present invention is an isotropic solution comprising a heated liquid crystal molecule and a gelling agent on one of the supports provided with an electrode layer and an active element if desired. Can be applied by a coating device such as a spin coater, a bar coater, or a roll coater, and then cooled to a temperature range where a liquid crystal gel can be formed. Immediately after the application, the other support may be arranged so as to be in contact with the solution via a spacer if desired,
From the viewpoint of simplicity of operation, it is preferable to dispose the other support after the liquid crystal gel is formed and the fluidity substantially disappears.

The liquid crystal device of the present invention described above is used in the same manner as a liquid crystal device having a dimming layer made of a conventional polymer-dispersed liquid crystal, for example, a screen blocking a view such as a building window or a show window; It can be used as a decorative display plate such as a plate; a display device of a clock or a calculator; a display device of a computer terminal; a display device of a projection.

[0026]

EXAMPLES The present invention will now be described in detail with reference to examples, but the scope of the present invention is not limited to the examples.

Synthesis Example 1 [(B) amino acid-based gelling agent (B
Synthesis of -1)] 14.04 g (0.0529 mol) of ZL-isoleucine (N-benzyloxycarbonyl-L-isoleucine) was dissolved in 150 ml of simple distilled ethyl acetate, and cooled under ice-cooling.
01 g (0.0582 mol) of N, N'-dicyclohexylcarbodiimide was added and stirred for 30 minutes. Subsequently, 14.26 g (0.0529 g) of octadecylamine was added under ice cooling, and the mixture was stirred for 1 hour. After returning to room temperature and stirring for 12 hours, the mixture was stirred in a 45 ° C. water bath for 10 hours. Further, the temperature of the hot water bath was raised to 60 ° C. and the mixture was stirred for 3 hours. The mixture was heated to remove insoluble N, N'-dicyclohexylurea by gravity filtration, and the filtrate was cooled. The resulting gel was filtered with suction over time. The collected material was heated and dissolved in single-distilled ethyl acetate, cooled, and the resulting gel was collected by suction filtration and dried to obtain the desired product. The yield was 20.09 g (74% yield).

Elemental analysis (C ₃₂ H ₅₆ N ₂ O ₃ , molecular weight 516.78) Calculated C NH 74.37 10.92 5.42 Found 74.21 10.99 5.62

Synthesis Example 2 [(B) Amino acid-based gelling agent (B
Synthesis of -2) 10.05 g (0.04 mol) of ZL-valine (N-benzyloxycarbonyl-L-valine) was dissolved in 50 ml of single-distilled ethyl acetate, cooled with ice, and cooled to 9.08 g (0%). (0.044 mol) of N, N'-dicyclohexylcarbodiimide, and the mixture was stirred under ice cooling for 1 hour. Next, 4.01 g (0.02 g)
Mol) of dodecamethylenediamine was dissolved in 100 ml of dehydrated chloroform and added. Further, 100 ml of dehydrated chloroform was added, and the mixture was stirred at room temperature overnight. Heated occasionally and allowed to react overnight. The reaction was cooled and filtered off with suction. The filtered material was dissolved by heating in 500 ml of n-propanol and cooled. The resulting gel was collected by suction filtration and dried to obtain the desired product. The yield was 6.68 g (50% yield).

Elemental analysis (C ₃₈ H ₅₈ N ₄ O ₆ , molecular weight 666.88) Calculated CNH 68.44 8.40 8.77 found 68.35 8.36 8.69

Example 1 (Formation of a gel-like substance) [0031] Using a liquid crystal compound (A-1) and an amino acid-based gelling agent (B-1), each mixture was prepared by changing the molar fraction of the amino acid-based gelling agent. The phase transformation behavior was observed in the following manner. That is, using a differential scanning calorimeter (DSC), 15 ° C./m up to 150 ° C.
After the temperature was raised at 150 ° C. to obtain a uniform isotropic solution, the phase transition (temperature) was examined when the temperature was lowered from 150 ° C. at 5 ° C./min. The phase state in each temperature range of the mixture was observed with a polarizing microscope. The result is shown in FIG. FIG. 1 shows an isotropic solution region, an isotropic gel region, a liquid crystalline gel region, and a crystal region formed by the mole fraction (mol%) of the amino acid-based gelling agent (B-1) and the temperature. Is shown. These regions appear by repeating reheating and cooling, and are thermoreversible. The mixture in the isotropic gel region and the liquid crystalline gel region was gel-like and had substantially no fluidity.

Example 2 (Formation of gel-like substance) The phase change behavior of the mixture was observed in the same manner as in Example 1 except that the amino acid-based gelling agent (B-2) was used. The result is shown in FIG. FIG. 2 shows that the isotropic solution region, the isotropic gel region, the liquid crystalline gel region, and the crystal region appear thermoreversibly as in the case of the first embodiment.

Example 3 (Evaluation of Electric Field Response of Liquid Crystalline Gel Material: Applied Voltage and Light Transmittance) Regarding the electric field response of the liquid crystal gel material generated in the liquid crystal gel region of Example 1, the applied voltage And the light transmittance. That is, two ITO transparent electrodes subjected to rubbing treatment after spin-coating a polyimide alignment film
Opposed at an interval of 6 μm and optically orthogonal to each other, a light control layer made of the liquid crystalline gel material is formed between the two electrodes to form a TN cell, and both sides of the TN cell Were provided with two optically orthogonal polarizing plates, and a device using a He—Ne laser (λ = 633 nm) as a light source was prepared. The light transmittance was measured while changing the applied voltage between two electrodes of this device. I ₀ of light transmittance when no voltage is applied, the light transmittance is I when a voltage is applied, the applied voltage (V) and shows the relationship of the I / I ₀ in FIG. As is clear from the results shown in FIG. 3, the amino acid-based gelling agent (B-1) was added at 0.25 mol% (d), 0.33 mol% (c), and 0.5 mol% (b), respectively. ), Although the contained liquid crystalline gel substance is not as large as the liquid crystal molecule (A-1), a remarkable decrease in luminance is observed with an increase in applied voltage, and a clear electric field response is exhibited.

Example 4 (Evaluation of Electric Field Response of Liquid Crystalline Gel Material: Response Time) The electric field response of the liquid crystal gel material of Example 1 was measured according to JIS C7072 using the same device as in Example 3. According to the method described below, evaluation was made by measuring the response time and the threshold voltage. That is, the light transmittance (T ₀ ) of the device when no voltage is applied is 0%, and the light transmittance (T ₁₀₀ ) when the light transmittance stops changing under a certain applied voltage is 100%. Is the time t required for the light transmittance to change by 90% from the start of voltage application.
₉₀ (response time ms) was measured. t ₉₀ is evaluated to be a high-speed response smaller. Further, a voltage (a threshold voltage v) at which the light transmittance became 90% was measured. Table 1 shows the results measured by the above method.

[0035]

[Table 1] * 10V, 300Hz

From the results shown in Table 1, it can be seen that the response time of the device using the liquid crystalline gel substance of the present invention in the light control layer is rather faster than that of the device using non-gelled liquid crystal molecules in the light control layer (13 ms). From 6 to 7 ms).

The preferred embodiments of the present invention are listed below. 1) (B) the amino acid-based gelling agent contains 1 to 10 organic groups having a divalent skeleton represented by the formula (I) per molecule,
More preferably, it has 1 to 4 pieces. 2) The organic group of the above 1) is a divalent organic group represented by the formula (II). 3) The organic group R in the formulas (I) and (II) is a branched chain saturated hydrocarbon group having 3 to 6 carbon atoms. 4) The organic group R is an isopropyl group, an isobutyl group,
Or an s-butyl group. 5) The (B) amino acid-based gelling agent has a carbon number of 6 to 3 other than the divalent organic group represented by the formula (I) or (2).
0 alkyl groups, alkylene groups, aryl groups, arylene groups, and / or arylalkyl groups. 6) (B) The molecular weight of the amino acid-based gelling agent is 2,000 or less. 7) (B) the amino acid-based gelling agent has a molecular weight of 150 to 10;
Be in the range of 00. 8) The amount of (B) the amino acid-based gelling agent is 0.1% with respect to the total of (A) the liquid crystal compound and (B) the amino acid-based gelling agent.
01 to 20 mol%. 9) The amount of (B) the amino acid-based gelling agent is 0.1% based on the total of (A) the liquid crystal compound and (B) the amino acid-based gelling agent.
1 to 10 mol%. 10) (B) The amino acid-based gelling agent is a compound having a chiral structure.

[0038]

According to the present invention, there is provided a gel-like substance containing a liquid crystalline compound having fluidity as a main component and having substantially lost its fluidity, particularly a gel-like substance exhibiting liquid crystalline properties. . And the above-mentioned gel-like substance showing liquid crystal properties shows a clear electric field response. Therefore, the present invention also provides a display device using the above-mentioned gel-like substance having liquid crystallinity as a light control layer.

[Brief description of the drawings]

FIG. 1 is a graph showing an isotropic solution region, an isotropic gel region, a liquid crystal gel region, and a crystal region formed by the mole fraction of amino acid-based gelling agent (B-1) and temperature. .

FIG. 2 is a graph showing an isotropic solution region, an isotropic gel region, a liquid crystalline gel region, and a crystal region formed by the mole fraction of amino acid-based gelling agent (B-1) and temperature. .

FIG. 3 is a graph showing an electric field response of a liquid crystalline gel substance formed from the liquid crystalline gel substance.

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[Procedure amendment]

[Submission date] April 14, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1: Liquid crystal compound (A-1) and amino acid-based gelling agent
The amino acid-based gelling agent (B-
3 is a graph showing an isotropic solution region, an isotropic gel region, a liquid crystalline gel region, and a crystal region formed by the mole fraction and the temperature of 1).

FIG. 2 shows a liquid crystal compound (A-1) and an amino acid-based gelling agent.
An amino acid-based gelling agent (B-
4 is a graph showing an isotropic solution region, an isotropic gel region, a liquid crystalline gel region, and a crystal region formed by the mole fraction and the temperature of 2) .

FIG. 3 shows a liquid crystal compound (A-1) and an amino acid-based gelling agent.
Is a graph showing an electric field response of the liquid crystal gel material which is a mixture or al formation of (B-1) and.

Claims (3)

[Claims] 1. A compound having (A) a liquid crystal compound and (B) a compound represented by the following formula (I): (Wherein R is a hydrogen atom or an organic group) a gelling agent having an organic group having a divalent skeleton represented by the following formula: 2. A liquid crystal material having a liquid crystal property.
2. The gel-like substance according to item 1. 3. A display device using the liquid crystalline gel material according to claim 2 for a light control layer.