RU2625121C2 - Method for obtaining homeotropically oriented liquid crystal layer of liquid crystal device - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: method for obtaining a homeotropically oriented liquid crystal layer of a liquid crystal device (LC) is described. The method comprises applying to the LC substrate a cell of the formula (1) R_FR_F'QZ or R_FR_F"QZ (1), where R_f=R₁=C_nF_2n+1O-,

,

,

, Q=CO or CS; Z=-NHR_H or -N(R_H)₂, where R_H alkyl C₁-C₆, Z=-NHR₃ or -N(R₃)₂, where R₃ alkyl C_kH_2k+1, k = 1-8, in a solvent, for example, in a cold solution 112. The substrate is soaked in a solution of the orientant (1), blasting, centrifugation, fixation of the layer of the orientant (1), and flushing of the loose coating are performed.

EFFECT: invention provides the most accurate homeotropic orientation of the liquid crystal of the LCD device, regardless of the structure of the orientator, the values of Q and Z, the orientation angle does not change and is 90 degrees.

4 cl, 2 dwg, 1 tbl, 1 ex

Description

Technical field

The invention relates to the field of manufacturing liquid crystal cells for liquid crystal devices, which can be widely used in various information systems.

State of the art

Known (RF patent No. 2491316) is a method of manufacturing a liquid crystal cell with a given orientation angle of the liquid crystal, which consists in applying a layer of a substance of an orientant in the form of a solution comprising polyorganosiloxane, a solvent and a gamma-aminopropyltriethoxysilane catalyst onto substrates of electrode conductive plates, followed by removal of the solvent and curing in the presence of a catalyst, polyorganosiloxane, and then the assembly of cells with the placement of a liquid crystal between the electrode conductive boards. As the polyorganosiloxane, oligodialkylalkyl hydride siloxane of the general formula (A) is used:

where R ', R'',R''' = CH ₃ , C ₂ H ₅ , n = 4-8, m = 6-9,

R ', R' '- different from each other. The microrelief formed on the substrate has geometric dimensions corresponding to the geometric dimensions of liquid crystal molecules and providing an angle of surface orientation in the range from 0 to 90 ° depending on the values of “m” and “n” of the organopolysiloxane of formula (A).

The invention provides for the production of liquid crystal cells for liquid crystal devices with the orientation of the liquid crystal at a certain predetermined angle.

The disadvantage of this invention is the difficulty of selecting a substance - an orientant for one or another orientation angle of the liquid crystal.

Amides and esters of perfluoropolyoxaalkylene sulfo or perfluoropolyoxaalkylene carboxylic acids are known and the method of their preparation, RF patent No. 2045544.

Usage: to obtain anti-friction anti-wear, extreme-pressure additives for lubricating oils and greases, as well as protective coatings against atmospheric corrosion.

The inventive amides and esters of perfluoropolyoxaalkylene sulfo or perfluoropolyoxaalkylene carboxylic acids of the General formula indicated in the text of the description. The compound is prepared by mixing at (-25) - (+ 8) ° C perfluoropolyoxaalkylene sulfonic or perfluoropolyoxaalkylene carboxylic acid fluorides of the general formula described in the description with a primary, secondary or tertiary amine or alkanolamine of the general formula

H _3-x N (R) _x , where x = 1, 2, 3, R = (C _n H _2n OH) _x , where n = 2, 3, 4, 6, 8, 10, - [(C ₂ H ₄ O) ₄ C ₃ H ₆ OH] _x for x = 2 or R = - (C ₂ H ₄ OCH ₃ ) _x , - (C ₂ H ₄ OS ₂ H ₅ ) _x , - (C ₂ H ₄ OS ₃ H ₇ ) _x , - [(C ₂ H ₄ O) ₅ -H] _x for x = 1 or (C _n H _2n OH) _x , x = 3, n = 2, 4, or a higher fatty alcohol of the general formula C _n H _{2n + 1} OH, where n = 6, 8, 10, and a compound from the group of alkali or alkaline earth metal fluoride, ammonium fluoride or aluminum fluoride, alkali metal carbonate or bicarbonate with a molar ratio of these compounds of 1.0: (1, 2-4.0) :( 1.5-3.0), respectively, followed by heating to 40-60 ° C, holding the reaction mixture at this temperature 0.6-3.0 h and the selection of the target product. Mixing of the reaction starting products can be carried out in the presence of a polyfluorocarbon solvent.

These compounds can be used to obtain anti-friction, anti-seize, anti-wear additives for lubricating oils and lubricants and, in addition, can be used as protective coatings against atmospheric corrosion.

In the present invention, the substance is not used as a starting substance to obtain a given orientation of the liquid crystal (orientant for the liquid crystal).

Also known "Composition for applying a protective molecular film" (RF patent No. 2215766).

The invention relates to compositions which, when applied to a solid surface, form a thin molecular protective film on it. The claimed composition includes a fluorinated surfactant (Fluorine-surfactant) and a solvent. As a fluorine-surfactant, the composition contains a substance of the general formula RFRF'QX, where RF is C _n F _{2n + 1} O; n is 1-8; RF '(-CF ₂ -CF ₂ -CF ₂ O) _m or where m = 3-50; Q = —CO— or —SO ₂ - and Z = —ORH, or OH, or —NHRH, or —N (RH) ₂ , where RH is an alkyl group of CH ₃ —C ₆ H ₁₃ and / or fluorinated acid amide of the general formula C _n F _{2n + 1} CNH ₂ , where n = 3-6, and / or amidoamine fluorinated acid of the general formula C _n F _{2n + 1} CONH (CH ₂ ) ₂ N (C ₂ H ₅ ) ₂ , where n = 3-6, and / or dialkylhydrazine of the general formula RFCONHN (RH) ₂ , and / or a pyragalol ester of the general formula and / or perfluoroenanthic acid of the general formula C _n F _{2n + 1} COOH, where n = 3-8, and / or telomeric acid General formula H (CF ₂ ) _n COOH, where n = 4-10, at a concentration of each Fluorine-surfactant 0.03-3.0 wt. %, and as a solvent, a polar, selected from the group methyl, ethyl, propyl, isopropyl alcohol, water, and / or non-polar, selected from the class of hydrocarbons with the number of carbon atoms C ₅ -C ₁₅ , and / or a halogen-containing solvent selected from trichlorethylene, tetrachlorethylene, chladone groups 122.

The invention allows to increase the degree of change in the surface energy of a solid, as well as to increase the resistance of the resulting coatings to aggressive liquid and gas environments and to provide the ability to control the thickness of coatings.

The objective of the invention is to expand the range of properties of the applied protective films.

The technical result of the invention is to increase the degree of change in the surface energy of a solid, as well as to increase the resistance of the resulting coatings to aggressive liquid and gas media and to provide the ability to control the thickness of the coatings.

In this case, it becomes possible to obtain films on the surface of a solid body from a few angstroms to fractions of a millimeter, which significantly expands the scope of their application as:

- protection of lubricant from spreading in friction units of mechanisms and devices;

- protection against penetration of moisture into the porous and fibrous structures of electronic circuit elements in microelectronics and radio engineering;

- protection against pollution of biological origin of ship hulls, yachts, columns, bridge supports and other surfaces working in the sea or river environment;

- protection against corrosion of metal surfaces;

- protection against pollution, stains and fingerprints on household and technical devices, panels with polished and chrome surfaces, medical instruments;

- to reduce friction in the rubbing pairs of machines and devices;

- to increase the efficiency of such technological processes as bending, drawing, stamping, pressing, crushing and grinding of both metals and non-metals;

- to prevent the passage of air and gases through a number of polymeric and other materials;

- to increase the durability of the forming surfaces of injection and molds, the internal surfaces of pipelines for transporting oil and gas, water cooling jackets of a number of systems.

However, in the present invention, the substance is not used as a guide for liquid crystal.

Disclosure of invention

The objective of the invention is the use to create a liquid crystal of such an orientant, which will provide the most accurate homeotropic orientation of the liquid crystal liquid crystal device.

This problem is solved due to the fact that the method of producing a homeotropically oriented layer of a liquid crystal of a liquid crystal device consists in applying an orientant - a substance of the formula (1) on the substrate of a liquid crystal cell

where R _F = R ₁ = C _n F _{2n + 1} O-,

Q = CO or CS,

Z = —NHR _H or —N (R _H ) ₂ , where R _{H is an} alkyl group with C ₁ -C ₆ ,

Z = -NHR ₃ or -N (R ₃ ) ₂ , where R _{3 is an} alkyl group C _k H _{2k + 1} k = 1 ÷ 8,

in a solvent, soaking the substrates in said orientant solution (1), blowing, centrifuging, fixing the orientant layer (1) and washing off the loose coating. Moreover, “n” = 1-10, and “m” = 3-60. Freon 112 is used as a solvent, soaking the substrates in the indicated solution of the orientant (1) is carried out at room temperature for 20 minutes, the layer of orientant (1) is fixed at a temperature of 120 ° C for one hour.

In the claimed method, the application of orientation films (orientant) on the substrate of the liquid crystal cell is carried out as follows: the substrates are washed and degreased, for example, by boiling in dimethylformamide, then the substrates are annealed at 300 ° C for 1 hour, after which the substrates are treated with ultraviolet light for 1 hour, then soaked in a solution of a substance of the general formula (1) in a solvent, for example, Freon-112 at room temperature for 20 minutes, then blowing and then centrifuging carbonation, then fix the layer of a substance of the general formula (1) at a temperature of 120 ° C for 1 hour and then wash off the loose coating substance.

List of drawings

In FIG. 1 shows the structure of a typical liquid crystal cell.

In FIG. 2 shows the arrangement of the constituent elements of the installation for measuring the angle of the LCD pretilt by the throughput of the LCD cell.

The implementation of the invention

The homeotropic (vertical) orientation of the liquid crystal is achieved by minimizing the surface polar adhesion energy [J. Cognard, "Alignment of Nematic Liquid Crystals and Their Mixtures", Molecular Crystals and Liquid Crystals, Suppl. 1 (Gordon and Breach, London, 1982); Russian translation by S. Konyar, “Orientation of nematic liquid crystals”. Minsk: Publishing House University. 1986] between the orientant layer and the liquid crystal.

A decrease in the surface polar energy of the orientant is achieved by introducing a perfluorinated fragment into the molecule of the substance used as the orientant.

It is known [Lebedev A.T. Mass spectrometry for the analysis of environmental objects. Moscow: Technosphere, 2013. - 632 p., ISBN 978-5-94836-363], that perforated compounds interact weakly with all substances.

The essence of the invention is to use as an orientant a substance of the general formula:

where R _F = R ₁ = C _n F _{2n + 1} O-,

Q = CO or CS,

Z = —NHR _H or —N (R _H ) ₂ , where R _{H is an} alkyl group with C ₁ -C ₆ ,

Z = -NHR ₃ or -N (R ₃ ) ₂ , where R _{3 is an} alkyl group C _k H _{2k + 1} k = 1 ÷ 8.

As a result of the experiments, it was shown that the value of the surface polar binding energy of the liquid crystal materials ZhK-440, ZhK-807, ZhK-1289 with the orientant (orienting film) of the substance of the general formula (1) is 10 ^-6 J / m ² , while the known organosilicon materials compounds (CBS) it was 10 ^-5 J / m ² .

That is, the known materials used as an orientant (orienting film), the values of the surface polar adhesion energy are 10-100 times greater than that of the claimed substance according to the formula (1). Previously, this substance was not used for this purpose, that is, as an orientant (orienting film) for the orientation of liquid crystals.

When using a substance as an orientant according to formula (1), regardless of the molecular structure and radicals used, a homeotropic orientation is always obtained.

The following experiments, indicated in the examples of using this substance according to the formula (1) for the orientant (orientation film) depending on the selected values of "n" and "m", confirm that, regardless of the values of "n" and "m", the orientation angle of the liquid crystal "θ" remains constant and equal to 90 °, that is, the orientation of the liquid crystal will be homeotropic regardless of the selected values of "n" and "m".

The orientation angle is also independent of the structure and of the fragments “Q” and “Z”; it does not change and amounts to 90 °.

This is achieved due to the small value of the surface polar adhesion energy of 10 ^-6 J / m ² declared for use by the substance according to the formula (1).

Sample preparation for measurement

The structure of a typical liquid crystal cell is shown in FIG. one,

where 1 is a layer of liquid crystal,

2 - cover - orientant,

3 - a layer of a transparent electrode,

4 - substrate.

The structure of a typical liquid crystal cell, consisting of upper and lower substrates 4 with transparent electrodes 3 deposited on their inner side (usually the material is indium and tin oxide (ITO)) and orientation layers (orientants) 2 that specify the orientation of the LC.

LCD cells were manufactured in accordance with the well-known procedure described in [Method No. GSSSD ME 221 - 2014 Method for the experimental calculation of determining the surface angle of inclination in liquid crystal cells with a uniform and inhomogeneous director distribution /, Ross. Scientific and Technical Center for Information on Standardization, Metrology and Conformity Assessment. M., 2014.19 p. Dep .. in FSUE STANDARTINFORM No. 915a - 2014 kk], [V. Belyaev, A. Solomatin, and D. Chausov, "Measurement of the liquid crystal pretilt angle in cells with homogeneous and inhomogeneous LC director configuration", Applied Optics, Vol. 52 Issue 13, pp. 3012-3019 (2013)]]. The application of orientants - films for orienting a liquid crystal is described in the indicated sources. The homeotropic orientation of the liquid crystal on the orienting surfaces of the orientant was carried out using substances of the general formula (1). The application of orientation films (orientant) on the substrate of the liquid crystal cell was performed using the following steps:

1. Washing and degreasing of substrates (in this case, boiling in dimethylformamide).

2. Annealing of the substrates at a temperature of 300 ° C for 1 hour.

3. Treatment of the substrates with ultraviolet for 1 hour.

4. Soaking in a solution of a substance of general formula (1) in a solvent, for example, Freon-112 at room temperature for 20 minutes.

5. Blowing, centrifugation.

6. Fixing a layer of a substance of general formula (1) at a temperature of 120 ° C for 1 hour.

7. Flush loose coating.

As reference cells, liquid crystal cells with a polyimide orienting coating were used. Due to the high polar adhesion energy W, such a coating provided planar orientation of the surface.

Placing a sample in a measurement setup

The surface angle of the liquid crystal was measured by the electro-optical method. The method is based on measuring the transmission of monochromatic polarized radiation passing through a liquid crystal cell with a given orientation distribution of the liquid crystal placed between crossed polarizers. The arrangement of the installation elements is shown in FIG. 2. The surface plane of the liquid crystal cell is orthogonal to the direction of the light beam. The cell is located between the crossed polarizers so that the plane of the preferred orientation direction makes an angle of 45 ° with the main axes of the polarizers.

An alternating voltage generator and a voltmeter were connected to the cell electrodes through connecting wires. The signal from the photodetector was fed to the input of a voltmeter or oscilloscope.

Using the measured transmission of the radiation transmitted through the liquid crystal cell, we calculated the difference in the phase delay of the polarized extraordinary and ordinary rays transmitted through the liquid crystal cell and, accordingly, the value of the rotation angle.

Before performing the electro-optical measurement procedure, the orientation type of the liquid crystal layer was checked.

The cell was rotated about the axis of the incident light beam around the axis corresponding to the preferred direction of orientation of the liquid crystal. For liquid crystal cells with a surface tilt angle other than zero, the dependence of the intensity on the rotation angle is symmetric, for homeotropic cells, the light intensity is minimal and does not depend on the angle of rotation of the cell.

For the experiment, we used a liquid crystal cell with an orientant (orienting film) of the substance according to formula (1) with sequential use of the formula (1) declared in the values of R _F ', R _F '', Q, Z, as well as various values of “n”, “m ".

Below are the results of experiments on the use of this substance according to the formula (1) for the orientant (orientation film).

Example 1. Use a substance according to the formula (1)

R _F R _F 'QZ,

where R _F = C _n F _{2n + 1} O-,

Q = CO,

Z = -NH-C _k H _{2k + 1} .

Then the substance according to the formula (1) has the chemical formula

Table 1 shows the values of the orientation angle of the liquid crystal "θ" at "n", "m" and "k", corresponding to their maximum, minimum and intermediate values.

Example 2. Use a substance according to the formula (1)

R _F R _F 'QZ,

where R _F = C _n F _{2n + 1} O-,

Q = CS,

Z = -NH-C _k H _{2k + 1} .

Then the substance according to the formula (1) has the chemical formula

Table 2 shows the values of the orientation angle of the liquid crystal "θ" at "n", "m" and "k" corresponding to their maximum, minimum and intermediate values.

Example 3. Use a substance according to the formula (1)

R _F R _F 'QZ,

where R _F = C _n F _{2n + 1} O-,

Q = CO,

Z = -N- (C _k H _{2k + 1} ) ₂ .

Then the substance according to the formula (1) has the chemical formula

Table 3 shows the values of the orientation angle of the liquid crystal "θ" at "n", "m" and "k", corresponding to their maximum, minimum and intermediate values.

Example 4. Use a substance according to the formula (1)

R _F R _F 'QZ,

where R _F = C _n F _{2n + 1} O-,

Q = CS,

Z = -N- (C _k H _{2k + 1} ) ₂ .

Then the substance according to the formula (1) has the chemical formula

Table 4 shows the values of the orientation angle of the liquid crystal "θ" at "n", "m" and "k" corresponding to their maximum, minimum and intermediate values.

Example 5. Use a substance according to the formula (1)

R _F R _F 'QZ,

where R _F = C _n F _{2n + 1} O-,

Q = CO,

Z = -NH-C _k H _{2k + 1} .

Then the substance according to the formula (1) has the chemical formula

Table 5 shows the values of the orientation angle of the liquid crystal "θ" with "n", "m" and "k" corresponding to their maximum, minimum and intermediate values.

Example 6. Use a substance according to the formula (1)

R _F R _F 'QZ,

where R _F = C _n F _{2n + 1} O-,

Q = CS,

Z = -NH-C _k H _{2k + 1} .

Then the substance according to the formula (1) has the chemical formula

Table 6. shows the values of the orientation angle of the liquid crystal "θ" with "n", "m" and "k" corresponding to their maximum, minimum and intermediate values.

Example 7. Use a substance according to the formula (1)

R _F R _F 'QZ,

where R _F = C _n F _{2n + 1} O-,

Q = CO,

Z = -N- (C _k H _{2k + 1} ) ₂ .

Then the substance according to the formula (1) has the chemical formula

Table 7 shows the values of the orientation angle of the liquid crystal "θ" at "n", "m" and "k" corresponding to their maximum, minimum and intermediate values.

Example 8. Use a substance according to the formula (1)

R _F R _F 'QZ,

where R _F = C _n F _{2n + 1} O-,

Q = CS,

Z = -N- (C _k H _{2k + 1} ) ₂ .

Then the substance according to the formula (1) has the chemical formula

Table 8 shows the values of the orientation angle of the liquid crystal "θ" at "n", "m" and "k", corresponding to their maximum, minimum and intermediate values.

Example 9. Use a substance according to the formula (1) R _F R _F "QZ,

where R _F = C _n F _{2n + 1} O-,

Q = CO,

Z = -NH-C _k H _{2k + 1} .

Then the substance according to the formula (1) has the chemical formula

Table 9 shows the values of the orientation angle of the liquid crystal "θ" at "n", "m" and "k" corresponding to their maximum, minimum and intermediate values.

Example 10. Use the substance according to the formula (1)

R _F R _F '' QZ,

where R _F = C _n F _{2n + 1} O-,

Q = CS,

Z = -NH-C _k H _{2k + 1} .

Then the substance according to the formula (1) has the chemical formula

Table 10 shows the values of the orientation angle of the liquid crystal "θ" with "n", "m" and "k" corresponding to their maximum, minimum and intermediate values.

Example 11. Use a substance according to the formula (1)

R _F R _F '' QZ,

where R _F = C _n F _{2n + 1} O-,

Q = CO,

Z = -N- (C _k H _{2k + 1} ) ₂ .

Then the substance according to the formula (1) has the chemical formula

Table 11 shows the values of the orientation angle of the liquid crystal "θ" at "n", "m" and "k" corresponding to their maximum, minimum and intermediate values.

Example 12. Use the substance according to the formula (1)

R _F R _F '' QZ,

where R _F = C _n F _{2n + 1} O-,

Q = CS,

Z = -N- (C _k H _{2k + 1} ) ₂ .

Then the substance according to the formula (1) has the chemical formula

Table 12 shows the values of the orientation angle of the liquid crystal "θ" at "n", "m" and "k", corresponding to their maximum, minimum and intermediate values.

Structural formulas of liquid crystal materials:

LCD 1282 components

one)

2)

3)

LCD 807 components

LCD 440

where R ₁ = OCH ₃ 4-butyl-4'-methoxyazoxybenzene (BMOAB or ZhK-434) and R ₂ = OSOS ₆ N ₁₃ 4-butyl-4'-heptanoyloxyazoxybenzene (BGOAB or ZhK-439), taken in the ratio 2: one.

As a result of experiments, it was shown that when using a substance according to formula (1) for various R _F ', R _F '', Q, Z and various values of “n”, “m”, the orientation of the liquid crystal (LC) remained strictly homeotropic. Also, when the spatial and structural arrangement of the CF ₃ group changed, the orientation of the liquid crystal remained homeotropic.

Thus, the task, namely the use of the substance of the orientant according to the formula (1) for homeotropic orientation, is completed.

Industrial applicability. All of the above experiments confirm the industrial applicability of this claimed invention.

Claims (13)

1. A method of obtaining a homeotropically oriented layer of a liquid crystal of a liquid crystal device, comprising applying to the substrate of the liquid crystal cell an orientant - a substance of the formula (1)

where R _F = R ₁ = C _n F _{2n + 1} O-,

Q = CO or CS, Z = —NHR _H or —N (R _H ) ₂ , where R _{H is an} alkyl group with C ₁ -C ₆ , Z = -NHR ₃ or -N (R ₃ ) ₂ , where R _{3 is an} alkyl group C _k H _{2k + 1} , k = 1-8, in a solvent, soaking the substrates in said orientant solution (1), blowing, centrifuging, fixing the orientant layer (1) and washing off the loose coating. 2. The method according to p. 1, characterized in that n = 1-10. 3. The method according to p. 1, characterized in that m = 3-60. 4. The method according to p. 1, characterized in that freon 112 is used as the solvent, soaking the substrates in the indicated solution of the orientant (1) is carried out at room temperature for 20 minutes, the layer of orientant (1) is fixed at a temperature of 120 ° C for one hour.

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