JP2000239663A - Liquid crystalline gel and liquid crystal device prepared by using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a gel-like substance which does not substantially have the fluidity of a liquid crystal compound, especially a gel-like substance which exhibits liquid crystalline properties, by causing a liquid crystalline compound to gel by mixing it with a gelling agent. SOLUTION: Preferably, a gelling agent having a linking group or groups, e.g. -NHCO- or a combination of -NH- with -CO-, capable of forming an intermolecular hydrogen bond or bonds is used. A compound having a part structure represented by the formula or a compound having at least two groups capable of forming intermolecular hydrogen bonds and at least two alkylene groups is preferable. Preferably, the gelling agent has a mol.wt. of 2,000 or lower and is used in an amount of 0.01-20 mol % of the sum of amounts of the gelling agent and a liquid crystalline compound. Preferably, the liquid crystalline compound exhibits a smectic phase and/or a chiral smectic phase, and a liquid crystalline gel which is formed by cooling a mixture containing a gelling agent having a gelation temperature lower than the clarifying temperature of the liquid crystal and is in an isotropic liquid state is especially preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a gel-like substance in which the fluidity of a liquid-crystalline compound originally having fluidity is substantially lost, particularly a gel-like substance exhibiting liquid-crystallinity and the above-mentioned gel-like substance exhibiting liquid-crystallineity. The present invention relates to a display device as a light control layer.

[0002]

2. Description of the Related Art It is well known that liquid and liquid compounds are used as liquid crystal compounds for liquid crystal displays. Further, a polymer dispersed liquid crystal in which a liquid crystal is dispersed in a polymer and a liquid crystal device in which a dimming layer is formed by the polymer dispersed liquid crystal are known. This liquid crystal device is bright and has good contrast without the need for a polarizing plate and alignment treatment.

The above-mentioned liquid crystal device using a polymer-dispersed liquid crystal as a light control layer is typically manufactured by a polymerization method.
That is, the above-mentioned liquid crystal device introduces a liquid photopolymerizable monomer and a liquid crystal between at least one of two substrates having electrodes and is transparent, and generates a polymer-dispersed liquid crystal by exposing to form a light modulating layer. It is manufactured by a forming method (see JP-A-6-340587, JP-A-7-17910 and JP-A-7-69983). However, this method has complicated manufacturing steps such as the necessity of introducing a liquid substance between two substrates in the step of manufacturing a liquid crystal device, and the necessity of a subsequent exposure step.

[0004] In addition, the above-mentioned liquid crystal device generally using a polymer-dispersed liquid crystal as a dimming layer is used for decorative display boards such as advertising boards,
When used for a display device of a clock and a calculator, a display device requiring a bright screen, especially a display device of a computer terminal, a display device of a projection, etc. (B) hysteresis phenomenon that lowers the margin of time-division driving and causes a problem in gradation display (light transmittance differs between when the voltage increases and when the voltage decreases). It is desired to reduce the phenomenon shown) as much as possible.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a gel-like substance in which the fluidity of a liquid-crystalline compound which originally has fluidity is substantially eliminated, and in particular, a gel-like substance exhibiting liquid-crystalline properties. It is in. It is another object of the present invention to provide a highly stable liquid crystalline gel material which uses a ferroelectric or antiferroelectric liquid crystal but has excellent shock resistance. Still another object of the present invention is to provide a display device using the liquid crystalline gel substance of the present invention as a light control layer.

Still another object of the present invention is to provide not only an excellent memory property and a wide viewing angle, but also an excellent stability of a liquid crystal layer, a high shock resistance, an easy gradation display, and a ferroelectric property. Another object of the present invention is to provide a display device in which a liquid crystal gel material from an antiferroelectric liquid crystal is used as a light control layer. Still other objects and advantages of the present invention will become apparent from the following description.

[0007]

According to the present invention, the above objects and advantages of the present invention are firstly achieved by gelling a mixture containing (A) a liquid crystal compound and (B) a gelling agent. Achieved by a liquid crystalline gel. According to the present invention, the above objects and advantages of the present invention are secondly achieved by a display device using the liquid crystalline gel of the present invention as a light control layer.

As the liquid crystal compound used in the present invention, liquid crystal molecules conventionally used in liquid crystal displays can be used. For example, "Liquid Crystal Device Handbook" edited by 142 Committee of the Japan Society for the Promotion of Science (19
89); various liquid crystal molecules such as biphenyl-based, phenylcyclohexane-based, phenylpyrimidine-based, and cyclohexylcyclohexane-based liquid crystals exhibiting a nematic or smectic phase described in p154 to 192 and p715 to 722, or a mixture of these liquid crystal molecules. Can be Alternatively, liquid crystal molecules exhibiting a chiral smectic layer can be used. Liquid crystal molecules having a ferroelectric or antiferroelectric smectic phase or a chiral smectic phase are preferably used. Specific examples of such liquid crystal molecules include the following compounds.

[0009]

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[0010]

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[0011]

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[0012]

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[0013]

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The chemical names of the compounds represented by the above formulas (E1), (E2), (E3) and (E4) are each 4
-N-heptyloxy-4'-cyanobiphenyl, p-methoxybenzylidene-p'-butylaniline, 4-n-
Decanoxy-4'-cyanobiphenyl and 4-n-pentyl-4'-cyanobiphenyl.

The compounds represented by the above formulas (E5) to (E49) are ferroelectric and have the above formulas (E50) to (E50).
The compound represented by (E54) is antiferroelectric. In the above formula, when they are present, each independently has the following meaning: n = 4 to 15, X ¹ = C
H _3, CN or Cl, m = 2~10, r = 5~14,
X ² = u or CN, Y = H, CN or Cl, l = 0
Or one.

Next, the gelling agent used in the present invention is generally a bonding group capable of forming an intermolecular hydrogen bond in a molecule, for example, a -NHCO- group, a -NH- group and a -C
It preferably has a combination with an O- group. As such a gelling agent, for example, the following formula (1)

[0017]

Embedded image Here, a compound having a partial structure represented by R is a hydrogen atom or a monovalent organic group, or a compound having two or more groups each capable of forming an intermolecular hydrogen bond in a molecule and an alkylene group is preferable. The alkylene group preferably has 4 or more carbon atoms, more preferably 6 to 20 carbon atoms.
It is. The molecular weight of the gelling agent is preferably 2000 or less,
More preferably, it is 150 to 1,000. Further, the gelling agent preferably has a chiral structure.

The compound having a partial structure represented by the above formula (1) preferably has the partial structure of 1 to 10 in the molecule.
And more preferably 1 to 4. The compound having the partial structure is referred to herein as an amino acid-based gelling agent. The partial structure represented by the above formula (1) preferably has the following formula (2)

[0019]

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The structure is represented by R in the formulas (1) and (2) 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, for example, an isopropyl group, an isobutyl group, an s-butyl group and the like. Specific examples of the organic group, including the preferred examples described above, are as follows.

[0021]

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The amino acid-based gelling agent may be an alkyl group or an alkylene group having 3 or more carbon atoms, preferably 4 to 30 carbon atoms, separately from the divalent organic group represented by the above formula (1).
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. Preferred specific examples of the amino acid-based gelling agent include ZL-isoleucine octadecylamide represented by the following formula (G1) and Z represented by the following formula (G2).
And L-valine dodecamethylene diamide and the following formulas (G3) to (G6) and (G9).

[0023]

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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 compound having two or more groups each capable of forming an intermolecular hydrogen bond and at least two alkylene groups in the molecule includes 1,2-bis- represented by the following formula (G7).
(11- (4-cyanobiphenyl-4′-oxo) undecylcarbonylamino) cyclohexane and 1,2bis- (undecylcarbonylamino) cyclohexane represented by the following formula (G8) can be mentioned as preferable examples.

[0026]

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In addition, as the gelling agent, for example, 1, 2,
3,4-dibenzylidene-D-sorbitol, 12-hydroxystearic acid, N-lauroyl-L-glutamic acid-α, γ-bis-n-butylamide, spin-labeled steroid, cholesterol derivative, aluminum dialkylphosphate, phenol type Cyclic oligomer, 2,3-
Gelling agents such as bis-n-hexadecyloxyanthracene and cyclic depsipeptide can be used.

The amount of the above-mentioned gelling agent necessary for gelling the liquid crystal molecules depends on the types of the liquid crystal molecules and the gelling agent, but is preferably 0.1 to the total of the liquid crystal molecules and the gelling agent. 0.1 to 20 mol%, more preferably 0.1 to 1 mol%.
0 mol% is used. As a method for obtaining a liquid crystal gel from liquid crystal molecules and a gelling agent, there is a method in which these are heated to form a uniform isotropic solution, and then cooled to obtain an optically anisotropic liquid crystal gel. However, it is not limited to this method.

When the liquid crystal compound comprises a liquid crystal exhibiting a smectic phase and / or a chiral smectic phase,
The liquid crystal and the gelling temperature are different from those of the smectic phase and / or
Alternatively, a liquid crystalline gel formed by cooling from a isotropic liquid state of a mixture of gelling agents lower than the clearing point of the liquid crystal exhibiting a chiral smectic phase is particularly preferable in the present invention.

As specifically shown in Examples described later, the liquid crystal molecules (E1) are used as liquid crystal molecules, and the gelling agent (G7) is used as a gelling agent in a molar ratio of 5.8.
When 9% is used, a liquid crystal gel having optical anisotropy between 71.5 ° C. and 32.5 ° C. can be obtained by cooling from an isotropic homogeneous mixed solution. This liquid crystal gel is
The liquid is returned to an isotropic solution by reheating, and a liquid crystal gel is obtained again by recooling.

Similarly, as specifically shown in Examples described later, for example, (A) a liquid crystal compound represented by the formula (E4) is used as a liquid crystal compound, and (B) an amino acid-based gelling agent is used as a liquid crystal compound. When the compound represented by the formula (G1) is used, and the molar fraction of the amino acid-based gelling agent (B) is 1 mol%, the isotropic homogeneous mixed solution is cooled to 45 to 35 ° C. A liquid crystalline gel material (liquid crystal gel) showing optical anisotropy between 35 ° C. and −18 ° C. can be obtained by further cooling. it can. The liquid crystalline gel substance of the present invention returns to an 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.

The liquid crystalline gel material of the present invention changes its orientation in accordance with the change in electric field strength, and exhibits 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 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.

A transparent or opaque electrode may be provided on the entire or partial surface of the substrate according to 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 formed by forming an isotropic solution composed of heated liquid crystal molecules 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.

[0039]

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 (G
Synthesis of 1)] 14.04 g (0.0529 mol) of ZL-isoleucine (N-benzyloxycarbonyl-L-isoleucine) is dissolved in 150 ml of simple distilled ethyl acetate, and 12.01 g (0.01 mol) is added under ice cooling. (0582 mol) of N, N'-dicyclohexylcarbodiimide and stirred for 30 minutes. Subsequently, under ice cooling, 14.26 g (0.0529 g) of octadecylamine was added, 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 (G
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 (0.044 mol) of N, N'-dicyclohexylcarbodiimide was added, and the mixture was stirred under ice cooling for 1 hour. Next, 4.
01 g (0.02 mol) of dodecamethylenediamine in 1
It was dissolved in 00 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

Synthesis Example 3 [Synthesis of Gelling Agent (G7)] A gelling agent (G7) was synthesized according to the reaction formula shown in FIG. The reaction conditions for each step are as follows. Step i) Bromoundecyl acid: 21.0 g Sulfuric acid: 6 mL Ethanol: 200 mL The reaction was carried out under reflux conditions for 24 hours to obtain ethyl bromoundecylate.

Step ii) Ethyl bromoundecylate: 11.6 g 4-cyano-4'-hydroxybiphenyl: 7.6 g Potassium carbonate: 8.6 g Dimethylformamide: 50 mL The mixture was refluxed for 24 hours, and the desired product 11- was obtained. Ethyl (4-cyanobiphenyl-4'-oxy) undecylate was obtained.

Step iii) Ethyl 11- (4-cyanobiphenyl-4'-oxy) undecylate: 7.7 g Ethanol solution with 1.4 g of potassium hydroxide dissolved therein: 1
The solution was refluxed at 00 mL for 24 hours to obtain the desired product, ethyl 11- (4-cyanobiphenyl-4'-oxy) undecylate.

Step iv) To 1.71 g of 11- (4-cyanobiphenyl-4'-oxy) undecanoic acid was added 2 drops of dimethylformamide, and the resulting mixture was added to 10 mL of thionyl chloride, and the solution was added at room temperature for 30 minutes.
After stirring for thirty minutes, thionyl chloride was volatilized and removed. 20 mL of dry THF was added to this and dissolved, and 0.28 g of 1,2-cyclohexanediamine was added while cooling with ice.
0.63 mL of triethylamine was added and reacted while stirring for 3 hours. The product was separated by column chromatography and purified by recrystallization. It was confirmed by NMR, IR analysis and the like that the compound was represented by the formula (G7).

Example 1 Using a liquid crystal molecule (E1) and a gelling agent (G7), the phase conversion behavior of each mixture in which the mole fraction of the gelling agent was changed was observed by the following method. (1) 150 ° C. using a differential scanning calorimeter (DSC)
The temperature was raised at a rate of 15 ° C./min until a uniform isotropic solution was obtained. (2) Separately, while cooling at a rate of 5 ° C / min from 150 ° C,
The phase state of the mixture was observed with a polarizing microscope.

The results are shown in FIG. 2 and FIG. FIG.
Indicates an isotropic solution region, an isotropic gel region, a liquid crystal gel region, a crystal region, and a cholesteric phase region formed by the mole fraction (mol%) of the gelling agent (G7) and the temperature. These regions appear by repeating reheating and cooling, and are thermoreversible. The mixture in the liquid crystal gel region was gel-like, and substantially no fluidity was observed. FIG. 3 is a DSC chart (temperature decrease) when the mole fraction of the gelling agent (G7) is 3.0 mol%.
It is shown that a slight exothermic peak exists at a temperature at which the liquid crystal gel region is formed when the temperature is lowered.

FIG. 4 shows the infrared absorption spectrum of the liquid crystal gel produced when the mole fraction of the gelling agent (G7) was 4.0 mol% and the temperature was 50 ° C. 328
Absorption is observed in 5cm ^-1 and 1637cm ^-1. The former is absorption corresponding to the expansion and contraction of NH, and the latter is absorption corresponding to the expansion and contraction of C = O, and does not appear unless the gelling agent (G7) is associated between molecules. The presence of these two absorptions strongly suggests that the gelling agents are associated via hydrogen bonds.

Example 2 Using the gelling agent (G8) and the liquid crystal molecules represented by the formulas (E2) and (E3) in addition to (E1) as the liquid crystal molecules, the same procedure as in Example 1 was repeated. Observation of the phase change behavior of the mixtures of various types revealed that when the liquid crystal molecules were (E1), the gelling agent mole fraction was 0.8 to 9 mol% and the temperature was 25 to 70 ° C.
In the case of (E2), the molar ratio of the gelling agent is 0.4.
(E3), the gelling agent mole fraction is 0.8 to 9 mol%, and the temperature is 32.
It was recognized that a liquid crystal gel having optical anisotropy was generated thermoreversibly in the range of -80 ° C.

Example 3 0.25 g of gelling agent (G8) and liquid crystal (E4) 12.2
5 g was dissolved in 100 g of methylene chloride at room temperature to obtain a uniform solution. This solution was air-dried in a fume hood to evaporate methylene chloride, thereby preparing a uniform liquid crystal gel comprising a gelling agent and liquid crystal molecules. This liquid crystal gel undergoes a phase transition from a liquid crystal gel to an isotropic liquid at 34.4 ° C. at a temperature rise (1 ° C./min) and 34.3 ° C. at a temperature decrease (1 ° C./min).
The liquid crystal transitioned from an isotropic liquid to a liquid crystal gel at room temperature, showed a liquid crystal gel state stably at room temperature, and had no fluidity. Next, (a)
A liquid crystal device having a light modulating layer made of a liquid crystal gel was prepared by the methods described in (b) and (b).

(A) A spacer having an average particle diameter of 16 μm is sprayed on two glass substrates (20 × 50 mm) having an electrode layer, and the liquid crystal gel is heated to be sandwiched in an isotropic liquid state. By allowing to cool, a liquid crystal device having a light control layer made of a liquid crystal gel was prepared. (B) The liquid crystal gel is heated and coated as an isotropic liquid on a glass substrate (20 × 50 mm) having an electrode layer using a bar coater, and allowed to cool to room temperature. A liquid crystal device having a light modulating layer made of a liquid crystal gel was prepared by forming a gel layer and overlaying a glass substrate having another electrode layer thereon. The results of the evaluation of the two obtained liquid crystal devices by the above method are described below. Note that the third embodiment is an example of black display on a white background.

[Method (A)] [Method (B)] (1) Drive voltage V ₁₀ : ₈₇ V ₉₀ : 18 18 (2) Contrast T ₉₀ / T ₀ : 11/1 12/1

The evaluation of the liquid crystal device was conducted according to JIS C
According to the method described below according to 7072 (the same applies hereinafter). (1) Drive Voltage The light transmittance (T ₀ ) of the device when no voltage is applied is set to 0%, and the transmittance (T ₁₀₀ ) when the light transmittance does not change as the applied voltage increases is 100%. As the applied voltage (volt) V ₉₀ and the light transmittance of 1 which become the light transmittance of 90%,
The applied voltage at which 0% was measured V _10. If V ₉₀ and V ₁₀ are 20 V or less, it is practical and evaluated as having a low driving voltage. (2) Contrast When the light transmittance of the light source when the light source is turned on is set to 100% and the light transmittance when the light source is turned off is set to 0% in a state where the device is removed from the photometry, the light transmission of the device when no voltage is applied. The light transmittance T ₉₀ at the applied voltage V ₉₀ measured in the above (1) was measured, and the contrast was evaluated by the following equation. The larger the value of the following formula, the better the contrast. Contrast = T ₉₀ / T ₀

Example 4 0.167 g of gelling agent (G7) and liquid crystal (E4) 4.9
g was dissolved in 100 g of methylene chloride at room temperature to obtain a uniform solution. This solution was air-dried in a fume hood to evaporate methylene chloride, thereby preparing a uniform liquid crystal gel comprising a gelling agent and liquid crystal molecules. This liquid crystal gel undergoes a phase transition from a liquid crystal gel to an isotropic liquid at 34.5 ° C. at a temperature rise (1 ° C./min) and from an isotropic liquid at 34.3 ° C. at a temperature drop (1 ° C./min). Transformation into a liquid crystal gel occurred, and the liquid crystal gel state was stably exhibited at room temperature, and there was no fluidity. Next, a liquid crystal device having a light control layer made of a liquid crystal gel was prepared by the method (b) of Example 3, and the liquid crystal device was evaluated. The results are described below.

(1) Drive voltage V ₁₀ : 6 V ₉₀ : 14 (2) Contrast T ₉₀ / T ₀ : 12/1

Example 5 0.334 g of gelling agent (G7) and liquid crystal (E4) 4.9
g was dissolved in 100 g of methylene chloride at room temperature to obtain a uniform solution. This solution was air-dried in a fume hood to evaporate methylene chloride, thereby preparing a uniform liquid crystal gel comprising a gelling agent and liquid crystal molecules. This liquid crystal gel undergoes a phase transition from a liquid crystal gel to an isotropic liquid at 34.7 ° C. at a temperature rise (1 ° C./min), and from an isotropic liquid at 34.3 ° C. at a temperature decrease (1 ° C./min). Transformation into a liquid crystal gel occurred, and the liquid crystal gel state was stably exhibited at room temperature, and there was no fluidity. Next, a liquid crystal device having a light control layer made of a liquid crystal gel was prepared by the method (a) of Example 3, and the liquid crystal device was evaluated. The results are described below.

(1) Drive voltage V ₁₀ : 8 V ₉₀ : 16 (2) Contrast T ₉₀ / T ₀ : 9/1

Example 6 0.089 g of gelling agent (G8) and 5 g of liquid crystal (E2)
Was dissolved in 100 g of methylene chloride at room temperature to obtain a uniform solution. This solution was air-dried in a fume hood to evaporate methylene chloride, thereby preparing a uniform liquid crystal gel comprising a gelling agent and liquid crystal molecules. This liquid crystal gel undergoes a phase transition from the liquid crystal gel to an isotropic liquid at a temperature rise (1 ° C./min) at 40.0 ° C. and from a isotropic liquid at a temperature decrease (1 ° C./min) at 39.0 ° C. Transformation into a liquid crystal gel occurred, and the liquid crystal gel state was stably exhibited at room temperature, and there was no fluidity. Next, a liquid crystal device having a light control layer made of a liquid crystal gel was prepared by the method (a) of Example 3, and the liquid crystal device was evaluated. The results are described below. The sixth embodiment is an example of black background white display.

(1) Drive voltage V ₁₀ : 7 V ₉₀ : 19 (2) Contrast T ₉₀ / T ₀ : 1/11

Example 7 (Formation of gel-like substance) The phase conversion behavior of each mixture using a liquid crystal compound (E4) and an amino acid-based gelling agent (G1) and changing the molar fraction of the amino acid-based gelling agent was determined. Observation was performed by the following method. That is, using a differential scanning calorimeter (DSC), 15 ° C./m up to 150 ° C.
After the temperature was raised at 150 ° C. to make 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 results are shown in FIG. FIG. 5 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 (G1) and the temperature. I have. 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 8 (Formation of gel-like substance) The phase change behavior of the mixture was observed in the same manner as in Example 7, except that the amino acid-based gelling agent (G2) was used. FIG. 6 shows the result. FIG. 6 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 seventh embodiment.

Example 9 (Evaluation of Electric Field Responsivity of Liquid Crystalline Gel Material: Applied Voltage and Light Transmittance) The electric field response of the liquid crystal gel material generated in the liquid crystal gel region of Example 7 was measured by applying an 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 Was 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.

The light transmittance when no voltage is applied is I ₀ , the light transmittance when a voltage is applied is I, and the applied voltage (V)
FIG. 7 shows the relationship between and I / I ₀ . As is clear from the results shown in FIG. 7, the amino acid-based gelling agent (G1) was added at 0.25 mol% (d), 0.33 mol% (c), and 0.5 mol%, respectively.
The mol% (b) of the contained liquid crystalline gel substance, although not as large as the liquid crystal molecule (E4), shows a marked decrease in luminance with an increase in applied voltage, and shows a clear electric field response. In FIG. 7, (a) shows the case where G1 is 1 mol%, and (e) shows the case where only E4 (excluding G1).

Example 10 (Evaluation of electric field response of liquid crystalline gel substance: response time) The electric field response of the liquid crystalline gel substance of Example 7 was measured in accordance with JIS C7072 using the same device as in Example 9. 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.

[0067]

[Table 1]

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

Example 11 Ferroelectric liquid crystal FELIX-SCE8 (Hoechst
And the mixing ratio of the gelling agent G8 were changed, and the mixture was stirred at 140 ° C. to obtain a transparent and uniform solution. These mixtures were cooled under a polarizing microscope at a rate of 1 ° C./min, and the phase change behavior was observed. FIG. 8 shows the results.

FIG. 8 shows the weight fraction (% by weight) of the gelling agent G8.
Solution region, isotropic gel region, nematic liquid crystal phase region (liquid crystal region), nematic liquid crystal gel region (liquid crystal gel region A), smectic A
A liquid crystalline gel region (liquid crystalline gel region B) and a chiral smectic C liquid crystalline gel region (liquid crystalline gel region C) are shown. These regions appear by repeating reheating and cooling, and are thermoreversible. The mixture in the isotropic gel region, the nematic liquid crystalline gel region, the smectic A liquid crystalline gel region, and the chiral smectic C liquid crystalline gel region was gel-like and had substantially no fluidity.

Of these mixtures, the ferroelectric liquid crystal FE
The mixing ratio of gelling agent G8 to LIX-SCE8 is 1
Weight percent of sample, rubbed IT with alignment film
Injection was carried out at 120 ° C. between O transparent electrodes (cell gap: 1.5 μm, rubbing direction: parallel) to produce a liquid crystal cell. When this liquid crystal cell was gradually cooled from 120 ° C. at a rate of 1 ° C./min, a liquid crystal phase appeared at 99 ° C.
, A chiral smectic C liquid crystalline gel region was observed. 50 showing chiral smectic C liquid crystalline gel region
When the liquid crystal cell was pressed in the rubbing direction using a roller at ℃, uniform C2 orientation could be obtained. In order to measure the shock resistance of this liquid crystal cell, a load was applied with a 1 cm ² metallic probe, and the load at which defects occurred was measured. As a result, a good result of 15 kg / cm ² was obtained.

Example 12 Ferroelectric liquid crystal FELIX-SCE8 (Hoechst
And the mixing ratio of the gelling agent G2 were changed, and the mixture was stirred at 140 ° C. to obtain a transparent and uniform solution. These mixtures were cooled under a polarizing microscope at a rate of 1 ° C./min, and the phase change behavior was observed. FIG. 9 shows the results. FIG. 9 shows an isotropic solution region formed by the weight fraction (% by weight) of the gelling agent G2 and the temperature;
It shows an isotropic gel region, a nematic liquid crystal phase region, a nematic liquid crystal gel region, a smectic A liquid crystal gel region, and a chiral smectic C liquid crystal gel region. These regions appear by repeating reheating and cooling, and are thermoreversible. The mixture in the isotropic gel region, the nematic liquid crystalline gel region, the smectic A liquid crystalline gel region, and the chiral smectic C liquid crystalline gel region was gel-like and had substantially no fluidity.

Among these mixtures, the ferroelectric liquid crystal FE
The mixing ratio of gelling agent G2 to LIX-SCE8 is 1
Weight percent of sample, rubbed IT with alignment film
Injection was carried out at 120 ° C. between O transparent electrodes (cell gap: 1.5 μm, rubbing direction: parallel) to produce a liquid crystal cell. When the liquid crystal cell was gradually cooled from 120 ° C. at a rate of 1 ° C./min, a liquid crystal phase appeared at 97 ° C.
, A chiral smectic C liquid crystalline gel region was observed. 50 showing chiral smectic C liquid crystalline gel region
When the liquid crystal cell was pressed in the rubbing direction using a roller at ℃, uniform C2 orientation could be obtained. In order to measure the shock resistance of this liquid crystal cell, a load was applied with a 1 cm ² metallic probe, and the load at which defects occurred was measured. As a result, a good result of 13 kg / cm ² was obtained.

Example 13 Ferroelectric liquid crystal FELIX-SCE8 (Hoechst
Was mixed at 140 ° C. to obtain a transparent and uniform solution. These mixtures were cooled under a polarizing microscope at a rate of 1 ° C./min, and the phase change behavior was observed. The results are shown in FIG. FIG. 10 shows an isotropic solution region, a nematic liquid crystal phase region, a smectic A liquid crystal phase region, a smectic A liquid crystal gel region, and a chiral smectic C liquid crystal formed by the weight fraction (% by weight) of gelling agent G9 and temperature. 3 shows a hydrophilic gel region. These areas appear by repeating reheating and cooling,
It is thermoreversible. The mixture in the smectic A liquid crystalline gel region and the chiral smectic C liquid crystalline gel region was gel-like and had substantially no fluidity.

Of these mixtures, the ferroelectric liquid crystal FE
The mixing ratio of gelling agent G9 to LIX-SCE8 is 1
Weight percent of sample, rubbed IT with alignment film
Injection was carried out at 120 ° C. between O transparent electrodes (cell gap: 1.5 μm, rubbing direction: parallel) to produce a liquid crystal cell. When the liquid crystal cell was gradually cooled at a rate of 1 ° C./min from 120 ° C., a liquid crystal phase appeared at 99 ° C.
As a result, a smectic A liquid crystalline gel region appeared. At this time,
It was observed that the fibrous aggregate of the gelling agent was oriented in the direction perpendicular to the orientation direction of the liquid crystal molecules (see the photograph in FIG. 11). When cooling was further continued, a chiral smectic C liquid crystalline gel region appeared at 55 ° C. When the liquid crystal cell was pressed in the rubbing direction using a roller at 50 ° C. showing a chiral smectic C liquid crystal gel region, a uniform C2 orientation could be obtained. In order to measure the shock resistance of this liquid crystal cell, a load was applied with a 1 cm ² metallic probe, and the load at which defects occurred was measured. As a result, a good result of 20 kg / cm ² was obtained.

The photograph in FIG. 11 shows the mixed liquid crystal FEL.
After filling a mixture of IX-SCE8 and 1% by weight of a gelling agent G9 into a liquid crystal cell having been subjected to parallel rubbing, the mixture was gradually cooled from a high temperature and photographed at a cooling temperature of 59 ° C. At 61 ° C). The liquid crystal is in a smectic A phase. In the photograph of FIG. 11, the rubbing direction (the orientation direction of the liquid crystal) is from the top to the bottom, and the black line running in the lateral direction (perpendicular to the orientation of the liquid crystal) in the photograph is an aggregate of the gelling agent (thickness: (About 1 to 3 μm), during which the liquid crystal is seen to be aligned in the form of stripes in the vertical direction of the photograph.

Comparative Example Ferroelectric liquid crystal FELIX-SCE8 (Hoechst
Was cooled from 140 ° C. under a polarizing microscope at a rate of 1 ° C./min, and the phase change behavior was observed. As a result, a nematic liquid crystal phase appeared at 100 ° C., a smectic A liquid crystal phase appeared at 80 ° C., and a chiral smectic C liquid crystal phase appeared at 60 ° C. This ferroelectric liquid crystal FELIX-SCE8
Was injected at 120 ° C. between rubbed ITO transparent electrodes with an alignment film (cell gap 1.5 μm, rubbing direction parallel to each other) to produce a liquid crystal cell. The liquid crystal cell was gradually cooled at a rate of 1 ° C./min from 120 ° C. to obtain a chiral smectic C liquid crystalline gel region.
When the liquid crystal cell was pressed in the rubbing direction using a roller at ℃, uniform C2 orientation could be obtained. In order to measure the shock resistance of this liquid crystal cell, a load was applied with a 1 cm ² metallic probe, and the load at which defects occurred was measured. As a result, it was 1 kg / cm ² .

[0078]

The ferroelectric liquid crystal or the antiferroelectric liquid crystal has attracted attention as a next-generation liquid crystal display because of its characteristics such as high-speed response, memory properties, and a wide viewing angle. However, there are problems such as low shock resistance and difficulty in gradation display. According to the present invention, a gel-like substance containing a ferroelectric liquid crystal or an anti-ferroelectric liquid crystal having fluidity as a main component and having substantially lost its fluidity, particularly, a stabilized (anti) strong liquid crystal A dielectric liquid crystal is provided. These stabilized liquid crystalline substances are used in addition to display devices, such as actuators, switching elements,
It can also be used as a sensor or a waveguide element.

[Brief description of the drawings]

FIG. 1 is a view showing a synthesis route of a gelling agent (G7).

FIG. 2 is an isotropic solution region and isotropic formed by a mole fraction (%) of a gelling agent (G7) and a temperature in a liquid crystal gel composed of a liquid crystal (E1) and a gelling agent (G7). 4 is a graph showing a gel region, a liquid crystal gel region, a crystal region, and a cholesteric phase region.

FIG. 3 is a DSC chart (falling temperature) of a liquid crystal gel composed of a liquid crystal (E1) and a gelling agent (G7) (a mole fraction of 3.0 mol%).

FIG. 4 is an infrared absorption spectrum of a liquid crystal gel when the liquid crystal (E1), the gelling agent (G7) (the mole fraction is 4.0 mol%), and the temperature is 50 ° C.

FIG. 5 shows a liquid crystal compound (E4) and an amino acid-based gelling agent (G
1 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 the amino acid-based gelling agent (G1) and the temperature of the mixture with 1). is there.

FIG. 6 shows a liquid crystal compound (E4) and an amino acid-based gelling agent (G
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 the amino acid-based gelling agent (G2) and the temperature of the mixture with 2). is there.

FIG. 7 shows a liquid crystal compound (E4) and an amino acid-based gelling agent (G
1 is a graph showing the electric field response of a liquid crystalline gel substance formed from a mixture with 1).

FIG. 8 shows a ferroelectric liquid crystal FELIX-SCE8 (Hoe
7 is a graph showing a phase change behavior of a mixture of a gelling agent (Gst) and a gelling agent (G8) formed depending on the mole fraction of the gelling agent and the temperature.

FIG. 9 shows a ferroelectric liquid crystal FELIX-SCE8 (Hoe
2 is a graph showing the phase change behavior of a mixture of a gelling agent (Gst) and a gelling agent (G2) formed by the mole fraction of the gelling agent and the temperature.

FIG. 10 shows a ferroelectric liquid crystal FELIX-SCE8 (Ho
5 is a graph showing the phase change behavior of a mixture of the gelling agent (G9) and a gelling agent (G9) formed by the mole fraction of the gelling agent and the temperature.

FIG. 11 is a photograph taken at a temperature of 59 ° C. when the mixture of FIG. 10 in which the ratio of the gelling agent (G9) is 1% by weight is filled in a cell subjected to a parallel rubbing treatment, gradually cooled from a high temperature, and cooled. .

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kenji Eiji 1918-16 Furisato, Ueda-shi, Nagano F-term (reference) 2H088 EA12 EA22 EA34 EA44 GA02 GA04 GA17 JA17 JA20 4H027 BA01 BA03 BA06 BA07 BD01 BD03 BD08 BD17 BD21 BD24 BE01 BE02 BE07 CA02 CB00 CB01 CD04 CJ04 CV02

Claims (9)

[Claims] 1. A liquid crystalline gel obtained by gelling a mixture containing (A) a liquid crystalline compound and (B) a gelling agent. 2. The liquid crystalline gel according to claim 1, wherein the liquid crystalline compound (A) shows a nematic phase, a smectic phase or a chiral smectic phase. 3. The liquid crystalline gel according to claim 1, wherein the liquid crystalline compound (A) exhibits a smectic phase or a chiral smectic layer and exhibits ferroelectricity or antiferroelectricity. 4. The gelling agent (B) is represented by the following formula (1): The liquid crystalline gel according to claim 1, wherein R is a compound having a partial structure represented by a hydrogen atom or a monovalent organic group. 5. The liquid crystalline gel according to claim 1, wherein the gelling agent (B) is a compound having at least two each of a group capable of forming an intermolecular hydrogen bond and an alkylene group in a molecule. 6. The liquid crystalline gel according to claim 1, wherein the molecular weight of the gelling agent (B) is 2,000 or less. 7. The gelling agent (B) is preferably 0.01 to 2 based on the total number of moles of the gelling agent (B) and the liquid crystal compound (A).
2. The liquid crystalline gel according to claim 1, occupying 0 mol%. 8. A mixture of a liquid crystal exhibiting a smectic phase and / or a chiral smectic phase and a gelling agent having a gelation temperature lower than the clearing point of the liquid crystal exhibiting the smectic phase and / or the chiral smectic phase, and the like. The liquid crystalline gel according to claim 1, which is formed by cooling from an isotropic liquid state. 9. A display device using the liquid crystalline gel according to claim 1 for a light control layer.