JPH0940962A - Liquid crystal composition and method for preparing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystal composition having excellent dispersibility, flowability and durability and varying in viscosity in response to the applied electric or magnetic field by using a composition comprising a specified liquid crystal compound, a surfactant and particles of a magnetic metal oxide and/or a magnetic metal. SOLUTION: This liquid crystal composition comprises a liquid crystal compound which is liquid at a specified temperature, a surfactant and particles of a magnetic metal oxide and/or a magnetic metal. This composition is prepared by adding an alkalifying agent to a suspension of particles of a magnetic metal oxide and/or a magnetic metal, adding a surfactant to the obtained alkaline suspension, adjusting the pH of the suspension to 2 or below, drying the obtained acidic suspension and mixing the dried product with a liquid crystal compound which is liquid at a specified temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal composition and a method for producing the same, and more specifically, it has excellent dispersibility, fluidity and durability, and a magnetic field (magnetic field has substantially the same meaning as magnetic field. Liquid crystal composition capable of varying the viscosity in response to an electric field (referring to a physical and chemical dictionary).

[0002]

2. Description of the Related Art Liquid crystals are roughly classified into a smectic phase, a nematic phase, and a cholesteric phase according to their molecular arrangement. The constituent molecules of the liquid crystal can be spatially rotationally moved, so that the liquid crystal molecules are directed in a specific direction by applying an electric field or a magnetic field. It has the property of being oriented to.

It is safe to say that the conventional liquid crystal compound has less responsiveness to a magnetic field than responsiveness to an electric field, and that it hardly responds to a magnetic field. Nematic liquid crystals are used in various devices by paying attention to their optical characteristics and electrorheology.
These utilize the electric field response of liquid crystal.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal composition exhibiting excellent responsiveness in both an electric field and a magnetic field, and in particular, further improved magnetic field responsiveness. A liquid crystal composition is provided. Another object of the present invention is to provide a simple method for producing such an excellent liquid crystal composition.

[0005]

The invention according to claim 1 for solving the above-mentioned problems is a liquid crystal compound, a surfactant, a magnetic metal oxide and / or a magnetic metal particle which is liquid at a predetermined temperature. The invention according to claim 2 is characterized in that the liquid crystal composition contains an alkali agent by adding an alkaline agent to a suspension in which magnetic metal oxide and / or magnetic metal particles are dispersed. A suspension is obtained, a surfactant is added to this alkaline suspension, the pH of the resulting suspension is adjusted to 2 or less, and the resulting acidic suspension is dried to obtain the dried product. A method for producing a liquid crystal composition, which comprises mixing a liquid crystal compound which is a liquid at a predetermined temperature.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid crystal composition of the present invention and the method for producing the same will be described in detail below.

<Liquid Crystal Composition> The liquid crystal composition of the present invention comprises a liquid crystal which is liquid at a predetermined temperature, a surfactant, and magnetic metal oxide and / or magnetic metal particles.

-Liquid Crystal Compound- Examples of the liquid crystal compound usable in the present invention include nematic liquid crystal compounds, smectic liquid crystal compounds and cholesteric liquid crystal compounds. Among these, nematic liquid crystal compounds and smectic liquid crystal compounds are preferable.

As the nematic liquid crystal compound and the smectic liquid crystal compound, azomethine compounds, azo compounds, azooxy compounds, ester compounds, stilbene compounds, biphenyl compounds, terphenyl compounds, cyanophenylcyclohexane compounds, trans. Examples thereof include cyclohexane compounds and pyrimidine compounds.

As the azomethine compound, N-
(4-ethoxybenzylidene) -4-n-hexylaniline, N- (4-butoxybenzylidene) -4-n-octyl-2-methylaniline, N- (4-proxybenzylidene) -4-n-octylaniline, N- (4-n
-Heptylbenzylidene) -4-cyanoaniline, N-
(4-n-octylbenzylidene) -4-cyanoaniline, N- (4-cyanobenzylidene) -4-ethylaniline, N- (4-methoxybenzylidene) -4-butanoyloxyaniline, N- (4-butane) Noyloxybenzylidene) -4-methoxyaniline, N- (4-methoxybenzylidene) -4- (3-methylpentanoyloxy) aniline, N- (4-n-hexyloxybenzylidene) -4- (5-methylhexa) Noyloxy) aniline, N- (4-n-butylbenzylidene) -4-β-cyanoethylaniline and the like.

Examples of the azo compound include n-butyl-
4- (4'-n-butylphenylazo) -phenyl carbonate, 4-ethoxy-4'-n-pentanoyloxyazobenzene, 4-n-pentyl-4'-methoxyazobenzene and the like can be mentioned.

The azooxy compounds include 4-n
-Hexyl-4'-butoxyazobenzene, 4-ethoxy-4'-n-hexanoyloxyazobenzene, 4-
Examples include n-pentyl-4′-n-pentanoyloxyazobenzene and 4-n-heptanoyloxy-4′-cyanoazobenzene.

The ester compounds include 4-n-
Butylbenzoic acid-4'-n-hexyloxylphenyl, 4-n-hexyloxybenzoic acid-4'-n-heptoxylphenyl, 4- (4'-n-pentyloxybenzoyloxy) benzaldehyde, 4-n -Hexylcarbonate-4'-n-pentoxyphenylbenzoate, 4- (4-n-butoxybenzoyloxy) benzoic acid-4'-n-hexyloxylphenyl, 4- (4
-N-Methoxybenzoyloxy) benzoic acid-4'-n
-Propylphenyl, 4- (4-n-methoxybenzoyloxy) benzoic acid-4 '-(4-butylphenoxycarbonyl) phenyl, 4-n-heptylbenzoic acid-4'
-Cyanophenyl, 4- (4-n-pentylphenyl)
Benzoic acid-4'-n-pentylphenyl, 4- (4-n
-Pentylphenyl) benzoic acid-4'-n-cyanophenyl, 4-n-hexylbenzoic acid-4'-isocyanophenyl, 4-n-octyloxy-3-cyanobenzoic acid-4'-n-pentylphenyl , 4- (4-n-octyl-3-cyanobenzoyloxy) benzoic acid-4'-n
-Pentylphenyl, 4- (4-n-pentylbenzoyloxy) benzoic acid-4'-n-pentylphenyl, 4
-(4-n-pentylbenzoyloxy) -3-chlorobenzoic acid-4'-n-pentylphenyl and the like can be mentioned.

The stilbene compound is 4,
4'-diethoxy-trans-stilbene, 4-ethoxy-4'-n-butyl-α-methyl-trans-stilbene, 4-ethoxy-2-methyl-4'-n-butyl-
Trans-stilbene, 4-ethoxy-4'-n-butyl-α-chloro-trans-stilbene, 4-ethoxy-4'-n-butyl-β-chloro-trans-stilbene, 4-ethoxy-4'-n -Octyl-β-chloro-
Trans-stilbene, 4-ethoxy-4 ′-(2-methylhexyl) -β-chloro-trans-stilbene and the like can be mentioned.

The biphenyl compound is 4-n
-Heptoxy-4'-nitrobiphenyl, 4-n-hexyl-4'-cyanobiphenyl, 4-n-octyl-
4'-cyanobiphenyl, 4-n-hexyloxy-
4'-cyanobiphenyl, 4-n-pentanoyloxy-4'-cyanobiphenyl, 4-n-heptyloxy-
4'-n-propylcarbonylbiphenyl, 4-decyl-4'-hexanoylbiphenyl, 4-hexyloxy-4'-hexanoylbiphenyl and the like can be mentioned.

As the terphenyl compound, 4-
n-propyl-4 "-cyano-p-terphenyl, 4-
n-octyl-4 ″ -cyano-p-terphenyl and the like can be mentioned.

Examples of the cyanophenyl cyclohexane compounds include 4-alkyl-cyclohexyl-4'-cyanophenyl and the like.

Examples of the trans-cyclohexane compound include 4- (trans-4-pentylcyclohexyl) benzonitrile, trans, trans-4'-n-
Propyldicyclohexyl-4-carboxylic acid, trans, trans-4'-propyldicyclohexyl-4-
Carbonitrile, trans-4- (4 "-n-pentylcyclohexyl-4'-cyanobiphenyl, trans-
1,4-bis- (4-n-propoxycarbonyl) cyclohexane, trans-1,4-bis- (4-n-nonyloxycarbonyl) cyclohexane and the like can be mentioned.

Examples of the pyrimidine compound include 5-n
-Hexyl-2- (4-hexyloxyphenyl) pyrimidine, 5-n-heptyl-2- (4-cyanophenyl) pyrimidine, 5-n-cyano-2- (4-n-pentyloxyphenyl) pyrimidine, 5 -Cyanophenyl-2-pentylphenyl-pyrimidine, 5- (4-n-
Butylphenyl) -2- (4-cyanophenyl) pyrimidine, 5-cyanophenyl-2-butylphenyl-pyrimidine, 5-n-propyl-2-4'-cyano-4-biphenyl) pyrimidine, 5-cyano-2 -(4'-n-
Propyl-4-biphenyl) pyrimidine and the like.

As the cholesteric liquid crystal compound,
Cholesterol derivatives and chiral mesogenic substances are mentioned.

Examples of the cholesterol derivative include cholesteryl bromide, cholesteryl-n-hexyl ether, cholesteryl-n-heptanoate, cholesteryl-n-heptyl carbonate, cholesteryl-n-heptylmercaptocarbonate, cholesteryl benzoate, cholesteryl-w-phenylheptano. And cholesteryl erucate, 4-dodecyloxy-1-naphthylidene-cholesteryl-p-aminobenzoate, and the like.

As the chiral mesogen substance,
N- (4-ethoxybenzylidene) -4- (2-methylbutyl) aniline, 4-ethoxy-4 '-(2-methylbutyl) azobenzene, 4-ethoxy-4'-(2-methylbutyl) azooxybenzene, 4- (2-methylbutyl) benzoic acid-4'-n-hexyloxyphenyl,
4-n-heptoxy-4 ′-(2-methylbutyloxycarbonyl) biphenyl, 4- [4- (2-methylbutyl) benzoyloxy] benzoate-4′-n-pentylphenyl, 4- [4- ( 2-Methylbutyl) benzoyloxy] benzoic acid-4'-n-cyanophenyl, 4
-[4- (2-Methylbutyl) benzoyloxy] benzoic acid-4'-n-nitrophenyl, 4- [4- (3-
Methylpentyl) benzoyloxy] benzoic acid-4 '
-N-methylphenyl, 4- (2-methylbutyl)-
4'-cyanobiphenyl, 4- (3-methylpentyl)
-4'-cyanobiphenyl, 4- [4- (2-methylbutyl) phenyl] benzoic acid-4'-n-butylphenyl, 4- [4- (2-methylbutyl) phenyl] benzoic acid-4'-n- Cyanophenyl, trans-4- (2-
Methylbutyl) cyclohexylcarboxylic acid-4'-cyanobiphenyl, 4-n-hexyloxybenzoic acid-4 '
-(2-methylbutoxycarbonyl) phenyl, 4-
(4-methylbutyl) -4 ″ -cyano-p-terphenyl and the like can be mentioned.

Among the various liquid crystal compounds described above, nematic liquid crystal compounds are preferable, and biphenyl compounds and cyanophenylcyclohexane compounds are particularly preferable. Among the biphenyl compounds, 4-alkyl-4 '
-Cyanobiphenyls are preferred. Among the cyanophenyl cyclohexane compounds, 4-alkyl-cyclohexyl-4′-cyanophenyls are preferable.

-Surfactant- As the surfactant which can be used in the present invention,
For example, anionic surfactants, cationic surfactants, amphoteric surfactants, and nonionic surfactants can be mentioned.

Typical examples of the anionic surfactant include organic acid salts such as carboxylic acid salts and sulfonic acid salts, sulfuric acid ester salts, and phosphoric acid ester salts.

Examples of the carboxylate include sodium laurate, potassium laurate, sodium myristate, sodium palmitate, sodium stearate, sodium oleate, potassium oleate, and ether carboxylate. Among these, polyoxyethylene alkyl ether acetate is preferable.

Examples of the sulfonate include higher alkyl sulfonate, α-olefin sulfonate, higher fatty acid ester sulfonate, dialkyl sulfosuccinate, higher fatty acid amide sulfonate, and alkylallyl sulfonate. Examples thereof include alkylbenzene sulfonate, alkylnaphthalene sulfonate, and formalin condensate of alkylallyl sulfonate. Among these, alkylbenzene sulfonate is preferable.

As the above-mentioned sulfate ester salt, higher alcohol sulfate ester salt (alkyl sulfate ester salt), secondary higher alcohol sulfate ester salt, alkyl ether sulfate ester salt, alkyl allyl ether sulfate ester, sulfate ester salt of higher fatty acid ester, Examples thereof include sulfuric acid ester salts of higher fatty acid alkylolamide, sulfated oil and the like. Of these, the alkyl ethyl sulfate ester salt is preferable.

Examples of the phosphate ester salts include sodium didecyl phosphate, sodium polyoxyethylene lauryl ether phosphate, sodium polyoxyethylene cetyl ether phosphate, sodium polyoxyethylene oleyl ether phosphate, and polyoxyethylene alkylphenyl ether phosphate. Examples thereof include sodium. Among these, sodium polyoxyethylene oleyl ether phosphate is preferable.

Typical examples of the cationic surfactant include amine salts and quaternary ammonium salts. Among these, the quaternary ammonium salt is preferable.

Examples of the amine salt include alkylamine salts, polyamines, aminoalcohol fatty acid derivatives and the like. Among these, amino alcohol fatty acid derivatives are preferable.

As the quaternary ammonium salt, an alkyl quaternary ammonium salt, a cyclic quaternary ammonium salt, a quaternary ammonium salt having a hydroxyl group, a quaternary ammonium salt having an ether bond, a quaternary ammonium salt having an amide bond, etc. Is mentioned. Of these, preferred are quaternary ammonium salts having an ether bond.

As the amphoteric surfactant, N-lauryl β-alanine, N-stearyl β-alanine, N,
N, N-trimethylaminopropionic acid, N-hydroxyethyl N, N-dimethylaminopropionic acid, N-
Methyl N, N-dihydroxyethylaminopropionic acid, N, N, N-trihydroxyethylaminopropionic acid, N-lauryl N, N-dimethylaminopropionic acid, N-myristyl N, N-dimethylaminopropionic acid, N- Palmitic N, N-dimethylaminopropionic acid, N-stearyl N, N-dimethylaminopropionic acid, N-hexyl N, N-dimethylaminoacetic acid, N-octyl N, N-dimethylaminoacetic acid, N- Decyl N, N-dimethylaminoacetic acid, N-
Undecyl N, N-dimethylaminoacetic acid, N-lauryl N, N-dimethylaminoacetic acid, N-myristyl N,
Examples thereof include N-dimethylaminoacetic acid, N-palmityl N, N-dimethylaminoacetic acid, N-stearyl N, N-dimethylaminoacetic acid, 1-pyridinium betaine and 1-α-picolinium betaine.

Examples of the nonionic surfactants include ether type nonionic surfactants, ether ester type nonionic surfactants, ester type nonionic surfactants, block polymer type nonionic surfactants, and nitrogen-containing nonionic surfactants. An ionic surfactant is mentioned as a typical example.

As the ether type nonionic surfactant, a single chain length polyoxyethylene ether type ether type nonionic surfactant; polyoxyethylene fatty alcohol ether, polyoxyethylene alkyl allyl ether, polyoxyethylene lanolin Examples thereof include polyoxyethylene alkyl or alkyl allyl ethers such as alcohols; ethylene oxide derivatives of alkylphenol formalin condensates. Among these, polyoxyethylene alkyl allyl ether is preferable. Among the polyoxyethylene alkyl allyl ethers, polyoxyethylene alkylphenyl ethers and the like are preferable.

The ether ester type nonionic surfactant is a polyoxyethylene sorbitan fatty acid ester,
Examples thereof include polyoxyethylene ethers containing an ester bond such as polyoxyethylene glyceryl monofatty acid ester, polyoxyethylene propylene glycol fatty acid ester, and polyoxyethylene sorbitol fatty acid ester; natural oils and fats, and polyoxyethylene derivatives of waxes. Among these, polyoxyethylene ether containing an ester bond such as polyoxyethylene sorbitol fatty acid ester is preferable.

Examples of the ester type nonionic surfactant include polyoxyethylene fatty acid ester and polyhydric alcohol ester.

Examples of the block polymer type nonionic surfactants include pluronic type nonionic surfactants, tetronic type nonionic surfactants, block polymers containing an alkyl group, and the like.

Examples of the nitrogen-containing nonionic surfactant include polyoxyethylene fatty acid amide, alkylolamide, polyoxyalkylamine and the like.

Of these, anionic surfactants and cationic surfactants are preferable. Furthermore,
As the surfactant to be combined with the magnetic metal oxide particles, an anionic surfactant, particularly a carboxylate is preferable, and as the surfactant to be combined with the magnetic metal, amine salt is preferable.

From another point of view, anionic surfactants are preferable among the above-mentioned various surfactants, and among them, organic acid salts, alkyl lactates, N-acyl amino acid salts, alkyl ether carboxylic acids. An anionic surfactant having a carboxyl group at the terminal of polyethylene oxide, which is a salt and is ether-bonded with an alkyl group, is particularly preferable. The alkyl group in the anionic surfactant having a carboxyl group at the terminal of polyethylene oxide ether-bonded with this alkyl group has 5 to 5 carbon atoms.
It is 30, preferably 10 to 24, and the number of repeating units of ethylene oxide in polyethylene oxide is 1 to 30, preferably 2 to 10.

These preferred anionic surfactants are:
Generally, it is supplied as a sodium salt or its aqueous solution.

Generally speaking, it is preferable that the above-mentioned various surfactants have sufficient solubility in the liquid crystal. From this point of view, when the liquid crystal is a cyanobiphenyl compound, the sodium salt of polyethylene tridecyl ether acetic acid, which exhibits high solubility, is preferable.

-Magnetic Metal Oxide and Particles of Magnetic Metal- The magnetic metal oxide in the present invention is represented, for example, by the following composition formula.

(MnO) _X (ZnO) _Y (Fe ₂ O ₃ ) _Z However, in the formula, X, Y and Z satisfy the following relationship.

0.2 ≦ X ≦ 1.0, 0.9 ≦ Z ≦ 1.1, X + Y = 1 The composition of these ferrites is determined according to the characteristics required for the liquid crystal composition. For example, when high magnetization is required, Fe ferrite and Mn ferrite are preferable, and when utilizing the change of magnetization with temperature, Mn-Z is used.
N-ferrite is preferred.

As the magnetic metal, in-liquid reduction method, vacuum deposition method, spark erosion method, thermal decomposition method, plasma CV
Examples include iron, nickel, cobalt or alloys thereof obtained by the D method and the like.

Magnetic metal oxide and magnetic metal particles are
The particle size is usually preferably 1 to 20 nm.

—Composition of Liquid Crystal Composition— The liquid crystal composition in the present invention is a liquid crystal compound such that the total amount of the liquid crystal compound, the surfactant and the particles of the magnetic metal oxide and / or the magnetic metal is 100% by weight. Is 40 to 99% by weight, preferably 50 to 90% by weight, the surfactant is 0.1 to 40% by weight, preferably 5 to 20% by weight, and the magnetic metal oxide and / or magnetic metal particles are 0. The content is arbitrarily determined from the range of 0.01 to 60% by weight, preferably 10 to 40% by weight. The liquid crystal compound, surfactant and magnetic metal oxide and /
Alternatively, when the content of the magnetic metal particles is within the above range,
Alternatively, by selecting from the above range, it becomes possible to further achieve the object of the present invention,
Specifically, the liquid crystal composition which is the final product has excellent dispersibility, fluidity and durability, and can be suitably used in a temperature range from room temperature to a wide range.

The liquid crystal composition of the present invention is used in order to further enhance the characteristics of the liquid crystal composition of the present invention, or the original characteristics of the liquid crystal composition of the present invention, as long as the object of the present invention is not impaired. In addition to the above, various additives may be contained in order to impart new characteristics.

Examples of the additives include other ER fluids, magnetic fluids, emulsions, capsule powders, polymers and the like.

-Production Method of Liquid Crystal Composition- The liquid crystal composition can be suitably produced by the production method of the present invention.

In the method of the present invention, first, an aqueous suspension in which magnetic metal oxide and magnetic metal particles are suspended is prepared. In the method of the present invention, an aqueous suspension containing 0.01 to 60% by weight of magnetic metal oxide and / or magnetic metal particles is prepared.

What is important in this invention is to prepare the aqueous suspension to be alkaline. The aqueous suspension can be easily made alkaline by adding an alkaline agent such as caustic soda to the aqueous suspension.
The alkaline agent is not limited to caustic soda, and is not particularly limited as long as it is a compound that can make the aqueous suspension alkaline. The pH of the aqueous suspension prepared to be alkaline is preferably 10 to 12.

In the present invention, a surfactant is added to the obtained alkaline suspension. The amount of the surfactant added is usually 30 to 100% by weight, preferably 50 to 70% by weight, based on the magnetic metal oxide and the magnetic metal in the alkaline suspension. The surfactant may be added to the alkaline suspension by diluting it with a solvent such as water, or the surfactant may be directly added to the alkaline suspension without using a solvent. Good.

In the present invention, the dried product and the liquid crystal compound are mixed. At this time, when the liquid crystal compound is liquid at room temperature, the dried product and the liquid crystal compound can be mixed as they are, but when the liquid crystal compound is not liquid at room temperature, the liquid crystal compound is made liquid by heating or the like, It is preferable to mix the liquid crystal compound in liquid form with the dried product.

The amount of the liquid crystal compound added is usually 40 to 9 with respect to the magnetic metal oxide and the magnetic metal in the dried product.
It is 9% by weight, preferably 50 to 90% by weight.

It is preferable to wash the dried product with alcohol before mixing the dried product with the liquid crystal compound. Examples of alcohols used for washing include methanol, ethanol, propanol, butanol and the like. Among them, methanol and ethanol are preferable.

-Uses of Liquid Crystal Composition- The liquid crystal composition according to the present invention is excellent in dispersibility, fluidity and durability, and is suitable for use as an ER fluid whose viscosity changes with the application of an electric field like a magnetic fluid. Can be done. Since the liquid crystal composition according to the present invention has such excellent characteristics, the liquid crystal composition according to the present invention has an actuator, a viscous damper, and
It is preferably used for various devices for holding load, devices or members for utilizing photoelectric characteristic changes such as clutches and optical shutters.

[0060]

Example A magnetic metal oxide was produced by the coprecipitation method. That is, ferrous sulfate [FeSO ₄ ] (special grade reagent) 0.1
Mol and ferric sulfate [Fe ₂ (SO ₄ ) ₃ ] (special grade reagent) 0.7 mol were dissolved in 1 liter of distilled water. A caustic soda aqueous solution was added to the obtained aqueous solution until the pH was about 11, and the aqueous solution was gelated.

Polyoxyethylene nonyl phenyl ether (manufactured by Nikko Chemicals Co., Ltd .; ECT)
20 g of D-6NEX) was added.

The above gelled product was dried at 60 ° C. in a vacuum drier to obtain a magnetic metal oxide (hereinafter simply referred to as magnetite).

40 g of the magnetite was sampled and placed in a glass tube bottle.

100 ml of ethanol was added to the glass tube bottle. After adding ethanol, the glass tube bottle was sonicated using an ultrasonic cleaner. After applying ultrasonic waves, the glass tube bottle was placed on a permanent magnet to precipitate magnetite. The magnetization of the permanent magnet at this time was measured by a Gauss meter and was found to be about 3,0
00 Gauss.

When magnetite was precipitated as described above, ethanol remained as a supernatant liquid, and this ethanol was removed by decantation.

The above washing with ethanol was performed 5 times.

[0067] After washing, cyanobiphenyl compounds in a solution of the glass tube bottle _{(C 5 H 11 -C 6 H} 4 -C 6 H 4
-CN) 40 g and add 8 using sand bath
The mixture was heated and stirred at 0 ° C. for 0.2 hours to completely remove ethanol.

After the ethanol was completely removed, the glass tube bottle of permanent magnet was placed and left for one day. The magnetization of the permanent magnet at this time was measured with a Gauss meter,
It was about 3,000 gauss.

After standing, the supernatant liquid crystal composition in the glass tube bottle was collected. After the collection, the liquid crystal composition was subjected to magnetization measurement by a magnetic balance (manufactured by Tamagawa Seisakusho).

FIG. 1 is a graph showing the results of measuring the magnetization of the liquid crystal composition.

Next, an electric field was applied to the above liquid crystal composition by a double cylinder tube type rotational viscometer to measure the viscosity.

FIG. 2 is a graph showing the viscosity measurement results of the liquid crystal composition. In FIG. 2, the plot shows the electric field strength, ◯ is 0.0 kv / mm, and Δ is 0.5 kv.
/ Mm, □ is 1.0 kv / mm, ◇ is 1.5 kv / m
m and x are 2.0 kv / mm.

Thus, a liquid crystal composition could be obtained.

[0074]

According to the present invention, it is possible to provide a liquid crystal composition capable of exhibiting remarkable photoresponsiveness and viscosity change not only in an electric field but also in a magnetic field. The liquid crystal composition of the present invention is a magnetic fluid having a good response to a magnetic field and an electric field, and is also an ER fluid. Therefore, the liquid crystal composition of the present invention can be applied to various applications such as an actuator that responds to a magnetic field or an electric field.

According to the present invention, it is possible to provide a method capable of easily producing a liquid crystal composition having such excellent characteristics.

[Brief description of drawings]

FIG. 1 is a graph showing a change in magnetization of a liquid crystal composition according to an example of the present invention.

FIG. 2 is a graph showing a change in viscosity of a liquid crystal composition according to an embodiment of the present invention when an electric field is applied.

Claims (2)

[Claims] 1. A liquid crystal composition comprising a liquid crystal compound which is liquid at a predetermined temperature, a surfactant, and particles of a magnetic metal oxide and / or magnetic metal. 2. An alkaline suspension is obtained by adding an alkaline agent to a suspension in which magnetic metal oxide and / or magnetic metal particles are dispersed, and a surfactant is added to the alkaline suspension. The pH of the suspension obtained thereafter is 2
A method for producing a liquid crystal composition, which comprises preparing the following, drying the obtained acidic suspension, and mixing the obtained dried product with a liquid crystal compound that is liquid at a predetermined temperature.