JP2002214617A - Chemical adsorption liquid and method of manufacturing chemical adsorption film using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly form a chemical adsorption film having uniform film thickness by dissolving a chemical adsorbing agent in at least two kinds of solvents varying in boiling point and applying the solutions to a base material, then drying the low boiling point solvent to concentrate. SOLUTION: The chemical adsorption solution prepared by dissolving a silane-based chemical adsorption material into the nonaqueous organic solvent, is a solvent mixture containing a first nonaqueous organic solvent and a second nonaqueous organic solvent having the boiling point higher than the boiling point of the first nonaqueous organic solvent. The difference between the boiling points is preferably >=10 deg.C. The boiling point of the first nonaqueous organic solvent is preferably below 120 deg.C and the boiling point of the second nonaqueous organic solvent above 150 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a monomolecular film. Further, the present invention relates to a method for manufacturing a liquid crystal alignment film for a liquid crystal display device comprising a monomolecular film.

[0002]

2. Description of the Related Art According to chemical adsorption, a thin film having a molecular length level having functions such as water repellency, oil repellency, and antifouling property can be formed. Therefore, the chemical adsorption film is expected to be applied to a wide range of applications such as a waterproof film and a protective film.

As a method for forming a monomolecular film, the Langmuir-Blodgett method (hereinafter referred to as the LB method) is widely known. The LB method utilizes the property that an amphiphilic organic molecule becomes a monomolecular film with a hydrophilic group directed downward on the water surface, and transfers the monomolecular film formed on the water surface to a solid substrate, This is a method of forming molecular films or their cumulative films. For example, a monomolecular film is formed on the water surface, and while the substrate, which has been immersed vertically in water in advance, is pulled up at a constant speed,
A monolayer on the water surface is deposited on the substrate.

As a more efficient method of forming a monomolecular film than the LB method, a solution of a chemically adsorbed substance is supplied to a substrate on which a chemical adsorption film is to be formed by offset printing, screen printing, or the like. In addition, a method of reacting a chemically adsorbed substance with the surface of a substrate and then removing an excess of the chemically adsorbed substance is also widely used.

[0005] Also in liquid crystal display devices, attempts have been made to use a chemically adsorbed film as a liquid crystal alignment film.

The liquid crystal alignment film is for maintaining the order of alignment of liquid crystal molecules, and conventionally, a coating film formed using a polyvinyl alcohol or polyimide solution has been used. These liquid crystal alignment films have been obtained by rubbing a coating film formed using a spin coater or the like using a felt cloth or the like. According to such a method, it is difficult to form a film having a uniform thickness on the entire surface of the substrate,
Unevenness and burn-in tend to occur on the panel display. Further, in order to reduce the power consumption by lowering the driving voltage of the panel, there is a demand for making the liquid crystal alignment film thinner. However, this method has a limit in its attempt.

[0007] On the other hand, the thickness of the chemisorption film is 0.1 mm.
It is as thin as 4 to 3 nm. Further, it is not necessary to perform a rubbing process.

[0008] The chemical adsorption film is formed by, for example, the LB method. According to the LB method, a monomolecular film of a polyamic acid derivative compound formed by an ionic bond reaction between a polyamic acid and a long-chain alkylamine is formed on the substrate surface on which the electrodes are formed, and furthermore, the deposited film is imidized. A polyimide film as a liquid crystal alignment film is obtained. Since the monomolecular film of the polyamic acid derivative compound deposited on the substrate by the LB method has single molecules having a long molecular length arranged along the pulling direction of the substrate, a polyimide obtained by imidizing the deposited film is used. The film has an alignment property of aligning liquid crystal molecules in one direction.

In this method, it is effective to increase the processing temperature or the concentration of the solution in order to shorten the time required for the process of fixing the chemically adsorbed substance on the surface of the substrate. When the treatment temperature is increased, there is a problem that equipment is required for the heat treatment. On the other hand, when the concentration of the solution is increased, the processing time can be more effectively reduced. However, when the concentration is simply increased, the viscosity of the solution increases, and thus there is a problem in handleability and the like. In addition, the chemisorbed substance reacts with moisture in the atmosphere to easily polymerize. When polymerized on the surface of the substrate, it becomes difficult to wash and remove excess chemisorbed substances remaining on the surface of the substrate in a later step.

Therefore, if only a low-boiling solvent such as hexamethylsilicone is used as the chemical adsorption solvent, the concentration of the adsorption solution adhering to the surface of the substrate rapidly rises due to evaporation of the solvent during the adsorption treatment. During the reaction, the rate of the adsorption reaction is accelerated, and the processing time is greatly reduced. However, on the other hand, it becomes easy to polymerize on the surface of the base material, and cleaning becomes difficult as described above. In order to avoid this, it is necessary to perform the treatment in a dry atmosphere having a relative humidity of 35% or less.

[0011]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a thin and uniform thickness chemisorption film in a short time.
And it aims at forming with high efficiency.

[0012]

In order to achieve the above object, a chemisorption solution of the present invention is a chemisorption solution obtained by dissolving a silane chemisorption substance in a nonaqueous organic solvent,
The non-aqueous organic solvent is a mixed solvent including a first non-aqueous organic solvent and a second non-aqueous organic solvent having a higher boiling point than the first non-aqueous organic solvent.

Next, the method for producing a chemisorption solution of the present invention is as follows.
The first non-aqueous organic solvent and the silane-based chemisorption substance are dissolved in a mixed solvent containing a second non-aqueous organic solvent having a higher boiling point than the first non-aqueous organic solvent, to prepare a chemisorption solution, The chemisorption solution is attached to the surface of a substrate, and the first nonaqueous organic solvent is preferentially evaporated while the second nonaqueous organic solvent in the chemisorption solution attached to the substrate remains. While concentrating and concentrating, chemically binding the end of the chemisorbed molecules in the chemisorption solution and the surface of the substrate, washing the surface of the substrate using a cleaning solvent, The method comprises removing the chemisorption solution remaining on the substrate.

[0014]

DETAILED DESCRIPTION OF THE INVENTION In the present invention, a silane-based chemisorbent is prepared by bringing a solution of a silane-based chemisorbent into contact with a substrate and fixing the silane-based chemisorbent in the solution to the surface of the substrate. A mixed solvent is used in the method for producing a chemically adsorbed film that forms

The present invention utilizes the fact that a solvent having a lower boiling point among a plurality of solvents is more likely to evaporate than other solvents, and in the step of supplying a solution of a silane-based chemisorbed substance to the surface of a substrate. Part of the solvent, ie the solvent with the lower boiling point, is intentionally evaporated. Thus, the treatment is performed using a solution having a higher concentration than that at the time when the solution is supplied to the base material.

The method for producing a chemisorption film of the present invention is characterized in that a silane-based chemisorption is carried out in a mixed solvent containing a first nonaqueous organic solvent and a second nonaqueous organic solvent having a boiling point higher than that of the first nonaqueous organic solvent. Dissolving the substance to prepare a chemisorption solution; and attaching the chemisorption solution to the surface of the substrate where the hydroxyl groups are exposed in a dry atmosphere; and By evaporating the non-aqueous organic solvent, and chemically bonding the end of the chemisorbed substance in the chemisorption solution and the surface of the substrate, and cleaning the surface of the substrate using a cleaning solvent Removing the chemisorption solution remaining on the substrate.

When a solvent that evaporates easily when reacting the base material with the chemisorbed substance is added to the chemisorption solution, the chemisorption solution supplied to the base material surface is gradually concentrated. By the concentration of the chemisorption solution, the reaction between the chemisorption substance and the substrate surface is accelerated, and the reaction between the two can be completed in a short time. The step of chemically bonding the end portion of the chemically adsorbed substance to the surface of the base material (that is, a hydrophilic group such as a hydroxyl group exposed on the surface) is completed before all the first non-aqueous organic solvent is volatilized. Alternatively, it may be continued for a predetermined time even after all of the first non-aqueous organic solvent has volatilized.

In the present invention, the amount of the second non-aqueous organic solvent in the mixed solvent is preferably in the range of 0.1% by weight to 20% by weight, more preferably 1% by weight to 10% by weight. The range is more preferred.

The difference in boiling point between the first non-aqueous organic solvent and the second non-aqueous organic solvent is preferably in the range of 10 ° C. to 200 ° C., and more preferably in the range of 20 ° C. to 100 ° C. .

The boiling point of the first non-aqueous organic solvent is 65
The temperature is preferably from 120 ° C. to 120 ° C.
The temperature is preferably from 0 ° C to 120 ° C. When the boiling point of the first non-aqueous organic solvent is lower than 65 ° C., the evaporation is too fast, and it is difficult to control the concentration.

The boiling point of the second non-aqueous organic solvent is 15
The temperature is preferably 0 ° C. or higher.

In the present invention, even after the binding treatment of the chemisorbed molecules, the chemisorbed substance remaining on the substrate is uniformly dissolved at a high concentration in the solvent, so that it reacts with the moisture in the atmosphere to solidify. This method greatly simplifies the cleaning process for removing excess chemical adsorbed substances solidified on the surface of the substrate after drying and removing all the solvent after removing the solvent. Can be. Also, for example, 50
% Even under a relative humidity of about%.

When the surface of the substrate thus cleaned is inclined in a specific direction including the vertical direction to remove the cleaning solvent from the surface of the substrate, the chemically adsorbed substance fixed on the surface of the substrate is removed. Can be oriented in an inclined direction.

The amount of the second non-aqueous organic solvent is
When the content is 10 parts by weight or less, preferably 5 parts by weight or less relative to 0 parts by weight, the effect of concentrating the chemically adsorbed substance by solvent evaporation can be enhanced, and the adsorption treatment time can be more effectively shortened.

Here, it is preferable that the chemisorbed substance contains a linear carbon chain or a siloxane bonding chain and a chlorosilyl group, an alkoxysilyl group or an isocyanatesilyl group.

In order to effectively evaporate the first non-aqueous organic solvent while suppressing the evaporation of the second non-aqueous organic solvent, the difference between the boiling points of the first and second non-aqueous organic solvents is preferably Is preferably 10 ° C. or higher, more preferably 30 ° C. or higher.

When the first non-aqueous organic solvent has a boiling point of 120 ° C. or lower, the solvent can be evaporated in a short time even at room temperature. In addition, the boiling point of the second non-aqueous organic solvent is 150
When the temperature is higher than or equal to ° C., when the first nonaqueous organic solvent is evaporated, the evaporation can be suppressed.

Preferably, as the first and second non-aqueous organic solvents, a solvent having a desired boiling point is selected from a methyl silicone solvent or a hydrocarbon solvent having a wide boiling point. For example, in a methyl silicone-based solvent, hexamethyldisiloxane pentamethylmethoxyldisiloxane or the like is used as a low-boiling first nonaqueous organic solvent to be evaporated, and a remaining high-boiling second nonaqueous organic solvent is used as a solvent. , Hexamethylcyclosiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, and the like.
In the hydrocarbon solvent, normal hexane, octane, hexane, isooctane and the like are used as the first non-aqueous organic solvent, and hexadecane, octadecane, xylene and the like are used as the second non-aqueous organic solvent.

The washing solvent is substantially free of water in order to dissolve and remove unreacted excess chemical adsorbed substances.
For example, it is preferable to use a solvent having a water content of 1 ppm or less. For example, when a non-aqueous organic solvent containing an alkyl group, a carbon fluoride group, a carbon chloride group or a siloxane group is used,
Chemically adsorbed substances can be efficiently removed.

The chemisorption film obtained as described above is
It can be used for a liquid crystal alignment film of a liquid crystal display device.

When the cleaning solvent remaining on the surface of the substrate is removed by inclining the surface of the cleaned substrate in a specific direction including the vertical direction, the chemical adsorption film formed on the substrate surface is oriented in the inclined direction. be able to. That is, by this draining, the alignment direction as the liquid crystal alignment film can be preliminarily determined.

Each of the above steps can be performed in a normal atmosphere. However, in order to stably form a good film, the relative humidity of the dry atmosphere is preferably 45% or less, more preferably. 30% or less. If the humidity of the atmosphere is high, the chemisorbable substance reacts with water and the film tends to become cloudy. This clouded film cannot be easily removed by washing.

The pretilt angle of the liquid crystal can be controlled by using a plurality of kinds of silicon-based chemisorbents having different critical surface energies. For example, a terminal or a part of a carbon chain or a siloxane bond chain is a carbon trifluoride group (—CF ₃ ), a methyl group (—C 3
H ₃ ), vinyl group (—CH ＝ CH ₂ ), vinylene group (—C
H = CH-), an ethynylene group (carbon - triple bond of carbon), a phenyl group (-C ₆ H _5), an aryl group (-C ₆ H ₄
-), a halogen atom, an alkoxy group (-OR;. R represents an alkyl group, 1 to 3 carbon atoms is preferred), cyano group (-CN), amino group (-NH _2), hydroxyl group (-O
H), carbonyl group (= CO), carboxy group (-CO
When a chemisorbed substance substituted with at least one organic group selected from O-) and a carboxyl group (-COOH) is used, the critical surface energy is 10 to 55 mN / m.
It can be controlled very easily within the range.

When the obtained liquid crystal alignment film is further exposed through a polarizing plate after washing or preliminary alignment, a liquid crystal alignment film having a stronger alignment control force can be obtained. At this time,
When a plurality of regions having different alignment directions are provided in the formed liquid crystal alignment film using a mask having a specific pattern, a multi-domain liquid crystal alignment film can be obtained.

In the exposure, for example, i-line (wavelength 365 nm) of an ultrahigh pressure mercury lamp, g
Line (436 nm), h line (405 nm) or sterilizing line (254 nm), KrF excimer laser (248n)
m) etc. are used. Among them, the sterilizing line of mercury lamp and K
An rF excimer laser is preferable because it is easily absorbed by most substances.

In the case of using a silane-based chemisorbing substance containing a linear carbon chain or a siloxane bonding chain and at least one silyl group selected from a chlorosilyl group, an alkoxysilyl group and an isocyanatesilyl group, When a non-aqueous organic solvent is used as the washing solvent, the silyl group can be removed without reacting. As the washing solvent, for example, a solvent having an alkyl group, a carbon fluoride group, a carbon chloride group or a siloxane group is used.

Before the step of applying the chemisorption solution to the surface of the substrate, if a hydroxyl-rich film is formed on the surface of the substrate,
A high-density chemisorption film can be formed. For example, a solution of a compound containing a plurality of chlorosilyl groups is applied to the surface of a substrate in a dry atmosphere. Removal of the solvent forms a liquid film of the compound. In this liquid film,
The dehydrochlorination reaction proceeds rapidly between the chlorosilyl group of the compound and the hydroxyl group on the substrate surface. After completion of the dehydrochlorination reaction, the substrate is washed with a non-aqueous organic solvent and taken out into the air. When the chlorosilyl group remaining on the substrate surface reacts with moisture in the air, SiOH bonds are formed on the surface, that is, hydroxyl groups are formed. A monomolecular film-like coating composed of an inorganic siloxane containing a large number of is formed.

When a film is to be selectively formed on the surface of the substrate, a chemical adsorption solution may be applied to the surface of the substrate by offset printing, screen printing, slit coating, roll coating, or the like.

The washing solvent has a boiling point of 100 to 2
The use of a material having a temperature of 50 ° C. facilitates cleaning of the surface, so that a chemically adsorbed film with few defects can be obtained.

The liquid crystal alignment film obtained by the present invention may be of any type, such as a so-called vertical electric field type liquid crystal display device represented by a twisted nematic type or an in-plane switching type so-called lateral electric field type liquid crystal display device. It can be used for a liquid crystal display device.

[0041]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings.

Example 1 A mixed solvent containing 99 parts by weight of hexamethyl silicone (boiling point: 100 ° C.) and 1 part by weight of decamethyltetrasiloxane (boiling point: 190 ° C.) was prepared. This mixed solvent contains CF as a silane-based chemisorbent.
₃ (CF ₂ ) ₇ (CH ₂ ) ₂ SiCl ₃ was dissolved to prepare a solution having a concentration of 0.5% by weight as a chemisorption solution.

Indium tin oxide alloy (ITO) on the surface
After cleaning and degreasing a glass substrate 1 provided with a transparent electrode made of, in a dry atmosphere having a temperature of 25 ° C. and a relative humidity of 30% or less, as shown in FIG. Dipped for 1 minute. After pulling up the glass substrate 1 from the liquid, it was left in the same atmosphere for 5 minutes. In the case of the chemically adsorbed solution attached to the substrate surface, the concentration of the chemically adsorbed substance in the adsorbed solution is reduced to about 30 times after 5 minutes because the low boiling organic solvent (hexamethylsilicone) evaporates preferentially. The time is 1/20 of the case of using the same concentration chemisorption solution using only decamethyltetrasiloxane as a solvent.
And

When the glass substrate 1 is brought into contact with the chemisorption solution 2, the silane-based chemisorption substance in the solution reacts with a hydroxyl group on the surface of the glass substrate 1 by a dehydrochlorination reaction, whereby the following formula (1) is obtained.
It is conceivable that it is fixed on the glass substrate 1 as shown in FIG.

[0045]

Embedded image

Thereafter, the substrate was washed with n-hexane, which is a washing solvent 3 dehydrated in the same dry atmosphere.

Further, as shown in FIG.
Was raised in the direction of the arrow from n-hexane 3 in a state where it was set in a desired direction, and was drained, and then exposed to air containing water. By this exposure, as shown in FIG.
It is considered that the chemically adsorbed substance 4 fixed above reacts with the moisture in the air and is bonded to the surface of the substrate 1 by a siloxane bond as shown in the following formula (2).

[0048]

Embedded image

The thickness of the chemically adsorbed film obtained as described above was about 1 nm. The critical surface energy of the film measured using the Zisman plot was about 10 mN / m. The contact angle with water was about 120 degrees. Further, in the adhesion test by the crosscut tape method (JIS K5400), no peeling was observed, and it was confirmed that the film had high peeling strength. From this, it can be seen that according to this example, a chemically adsorbed film having excellent durability and antifouling property was obtained.

Note that FT-IR (Fourier Transform Inf)
As a result of analysis with a rared spectrometer, the carbon chains of the chemically adsorbed substance 4 fixed on the substrate 1 were oriented in a direction slightly deviated from a draining direction indicated by an arrow in FIG.

Example 2 A mixed solvent containing 99.5 parts by weight of hexamethyl silicone (boiling point: 100 ° C.) and 0.5 part by weight of hexadecane (boiling point: 287 ° C.) was prepared.

Next, CH as a chemisorbing substance is used.
₃ (CH ₂ ) ₁₄ SiCl ₃ and C ₆ H ₅ CH = CHCOC ₆ H ₄
A mixture containing O (CH ₂ ) ₆ SiCl _{3 in} a molar ratio of 1: 1 was dissolved in this mixed solvent to prepare a 1% by weight solution as a chemisorption solution. Here, CH ₃ (C
H ₂ ) ₁₄ SiCl ₃ is a linear hydrocarbon and has a functional group at its terminal that controls the surface energy of the coating. On the other hand, C
_{6 H 5 CH = CHCOC 6 H} 4 O (CH 2) 6 SiCl 3 may
It has a photosensitive group.

After a glass substrate provided with a transparent electrode made of ITO on the surface is washed and degreased, it is immersed in the obtained chemisorption solution for 1 minute in a dry atmosphere at a temperature of 25 ° C. and a relative humidity of 30% or less. did.

After the glass substrate was pulled out of the solution, it was left in the same atmosphere for 5 minutes. This treatment time is one-fiftieth that in the case of using a chemisorption solution of the same concentration using only hexadecane as a solvent. Assuming that all hexadecane remains during the treatment and that all hexamethylsilicone evaporates, the concentration of the chemisorbed substance in the chemisorption solution is concentrated to about 70 times.

By bringing the glass substrate into contact with the chemisorption solution, the two kinds of chemisorption substances in the solution are converted into the following formulas (3) and (4) by a dehydrochlorination reaction with hydroxyl groups on the glass substrate surface. It is considered to be fixed on a glass substrate as shown.

[0056]

Embedded image

Thereafter, the substrate was further washed with n-hexane dehydrated in the same dry atmosphere.

Further, after the substrate is pulled up from n-hexane while the substrate is set in a desired direction and drained, a humidity of 50% is applied.
% In air. It is considered that this exposure causes the chemically adsorbed substance fixed on the glass substrate to react with moisture in the air and to be expressed by the following equations (5) and (6).

[0059]

Embedded image

That is, as shown in FIG. 4, the chemically adsorbed film 5 formed by the reaction of the chlorosilane-based chemically adsorbed substance is
It is bonded via a siloxane covalent bond to a portion of one surface containing a hydroxyl group.

The thickness of the film obtained as described above was about 1.7 nm. As a result of FT-IR analysis, the carbon chains of the chemically adsorbed substance fixed on the substrate were oriented so as to be inclined in the draining direction.

The pair of glass substrates having the chemically adsorbed film 5 formed on the surface thereof as described above are faced to each other so that the orientation direction of the chemically adsorbed film is anti-parallel.
A liquid crystal cell having a cell gap of 20 microns was assembled.
When a nematic liquid crystal (ZLI4792; manufactured by Merck) is injected into the liquid crystal cell and the alignment state is confirmed, the injected liquid crystal molecules are aligned with the liquid drain direction at the time of washing, and about 4 ° with respect to the substrate. It was oriented at a pretilt angle. Note that F
According to the analysis by T-IR, the carbon chain of the chemisorbed substance in the film was oriented with a certain degree of inclination in the draining direction.

A liquid crystal display panel was manufactured using the chemically adsorbed film formed as described above as a liquid crystal alignment film.

A chemically adsorbed film as a liquid crystal alignment film was formed on each of a pair of glass substrates having electrodes formed on the surface in advance in the same manner as described above.

As shown in FIG. 5, a polarizing plate 6 (HNP'B: manufactured by Polaroid) is provided on a chemically adsorbed film on a glass substrate 11.
Were superimposed so that the optical axis of the transmitted light indicated by an arrow in the drawing was at an angle of 87 degrees with the direction in which the glass substrate was pulled up in the liquid drainage. Then, using a 500 W ultra-high pressure mercury lamp, the wavelength transmitted through the polarizing plate 6 from above in the figure was 365 nm.
Was irradiated to the chemisorption film at 400 mJ. At this time,
The output after passing through the polarizing plate 6 was 3.6 mW / cm ² .

According to FT-IR, no change was observed in one of the two chemisorbed substances contained in the chemisorbed film, but the other was the photosensitive group, ie, (C ₆ H ₅ C).
It was confirmed that H = CHCOC ₆ H ₄ −) polymerized by light irradiation and changed as in the following formula (7).

[0067]

Embedded image

As a result, as shown in FIG. 6, the exposed chemical adsorption film 5 ′ is oriented along the optical axis direction of the irradiation light indicated by the arrow in the figure.

FIG. 7 shows the molecular structure of the obtained film.

Further, a liquid crystal cell having a cell gap of 20 μm was assembled by combining these two substrates 11 such that the chemically adsorbed films 5 ′ faced each other and the orientation directions were antiparallel. A nematic liquid crystal (ZLI4792; manufactured by Merck) is added to this liquid crystal cell.
Was injected and the alignment state was confirmed. The injected liquid crystal molecules were aligned at a pretilt angle of about 4 ° with respect to the substrate along the polarization direction.

According to the analysis using FT-IR, the critical surface energy and the tilt angle of the chemisorption film 5 ′ did not change, but the orientation direction of the linear carbon chain of the chemisorption substance was It changed in a direction substantially parallel to the optical axis, and the variation in alignment was improved as compared to immediately after draining.

In order to align the orientation of the adsorbed molecules in one direction, the transmission axis of the polarizing plate (that is, the optical axis of the transmitted light) is required.
Rather than completely intersect the draining direction at 90 °, it is necessary to shift the angle slightly, preferably several degrees or more. Should they completely cross at 90 °, each molecule would be 180
° They may face two different directions. When the transmission axis of the polarizing plate is adjusted so as to be parallel to the draining direction of the cleaning liquid, a chemically adsorbed film having more excellent alignment regulating force can be obtained.

When it is desired to selectively change the orientation direction on the substrate surface, the liquid is pulled up beforehand and drained.
A polarizing plate whose transmission axis is directed in a direction different from the draining direction and a mask having a desired pattern are superimposed on the substrate, and the wavelength is set to 36.
When a 5 nm ultraviolet ray is irradiated at an energy of 200 to 500 mJ, only the irradiated portion changes its orientation direction, and the orientation direction changes in a pattern in the alignment film in the same plane, that is, the pulling direction and the polarization direction respectively. A plurality of portions along which the liquid crystal is aligned can be provided.

CH ₃ (CH ₂ ) ₁₄ S as a chemisorbent
iCl ₃ and C ₆ H ₅ CH ＝ CHCOC ₆ H ₄ O (CH ₂ ) ₆ S
The chemical adsorption film was formed by changing the mixing ratio with iCl ₃ . As a result of the same evaluation, CH ₃ (CH ₂ ) ₁₄ Si
As the Cl ₃ ratio was reduced, the critical surface energy of the film changed from 24 mN / m to 35 mN / m and the pretilt angle changed from 86 ° to 3 °. 50: 1 to 1:50
In the range, a practically preferable value was obtained. The critical surface energy of the film and the pretilt angle of the liquid crystal can be controlled by adjusting the compounding ratio of the chemisorbed substance.

This is because the carbon chain used in the present example is-
Not limited to a mixture of a silane-based chemisorbent represented by (CH ₂ ) _14- and a silane-based chemisorbent having a photosensitive group having a carbon chain represented by-(CH ₂ ) _6- , and other chemisorptions The same applies to mixtures of substances. For _{example, - (CH 2) n -} (n is integers from 1 to 25) mixture or a chemical adsorbate having a carbon chain represented by the siloxane bond chain (- (SiO)
_n −; n is an integer of 1 to 15), the orientation direction can be controlled by the polarization direction, and the pretilt angle can be similarly controlled by the critical surface energy of the chemisorption film. it can.

As a chemisorbing substance containing fluorine, for example, CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ SiCl ₃ is added as a chemisorbing compound instead of CH ₃ (CH ₂ ) ₁₄ SiCl ₃ , the critical surface energy increases. Was reduced to 14 mN / m.
When 20% by weight is added, the pretilt angle of the liquid crystal is almost 9
Although it was 0 degrees, when the cell was driven by applying a voltage, a very uniform alignment change was exhibited.

When a chemisorbing substance containing an alkoxysilyl group or an isocyanatesilyl group is used as the chemisorbing substance, the reaction rate is slightly lowered, but a chemisorption film which also functions as a liquid crystal alignment film can be formed. did it.

Example 3 In a dry atmosphere having a relative humidity of 30% or less, Cl ₃ SiOSiCl ₃ was dissolved in dehydrated toluene to prepare a solution having a concentration of 1% by weight. Further, in the same dry atmosphere, the glass substrate was immersed in the obtained solution for 1 minute. The lifted glass substrate was left in the same atmosphere for 10 minutes to evaporate the toluene adhering to the substrate. Then, when the substrate is washed with well-dehydrated chloroform, a dehydrochlorination reaction occurs between the hydroxyl group on the substrate surface and Cl ₃ SiOSiCl _3, and as shown in FIG.
Was formed on the substrate surface via a -SiO- bond. Thereafter, the substrate was further taken out into the air and reacted with moisture in the air. As a result, a siloxane monomolecular film 7 ′ containing a large number of hydroxyl groups on the surface was formed on the surface of the substrate 1 via a —SiO— bond as shown in FIG.

The siloxane monomolecular film 7 'formed at this time is firmly bonded to the substrate 1 through a chemical bond of -SiO-. In addition, the obtained coating film has SiO 2 on the surface.
It has many H bonds. In particular, about 2 to 3 times the number of hydroxyl groups was generated as compared with the surface of the glass substrate 1. The treated part in this state had extremely high hydrophilicity.

After the above treatment, a chemically adsorbed film was formed using a chemically adsorbed solution in the same manner as in Example 1.

As a result, a chemically adsorbed film similar to that shown in FIG. 1 was formed in a state of being chemically bonded by a siloxane covalent bond via the hydroxyl-rich monomolecular film 7 ′. The thickness of the obtained film was about 1.8 nm. At this time, since a monomolecular film 7 'having a large number of hydroxyl groups is formed on the surface of the substrate 1 on which the chemically adsorbed substance is fixed, a film having a higher density than in Example 1 can be obtained. The surface of the resulting membrane became lipophilic.

According to the present example, the chemical adsorption time, which usually takes 1 to 2 hours in the conventional film formation, was greatly reduced to 11 minutes by the formation of the hydroxyl group-rich film and the use of the mixed solvent.

The pair of substrates obtained as described above is
The liquid crystal cell having a cell gap of 20 microns was assembled by assembling the chemisorption films so as to face each other, and further, so that the orientation directions were antiparallel. When a nematic liquid crystal (ZLI4792; manufactured by Merck) was injected into this liquid crystal cell and the alignment state was confirmed, the injected liquid crystal molecules were aligned at a pretilt angle of about 5 ° with respect to the substrate along the drainage direction. Was.

As the silyl compound containing a plurality of chloro groups, instead of Cl ₃ SiOSiCl ₃ , Cl-
Similarly, when (SiCl ₂ O) _n -SiCl ₃ (n is an integer) was used, a high-density liquid crystal alignment film could be formed in a short time. When n is 0 to 3, handleability when forming a hydroxyl group-rich film is excellent.

Example 4 ClS as Chemically Adsorbed Material
i (CH ₃ ) ₂ OSi (CH ₃ ) ₂ OSi (CH ₃ ) ₂ OSi (C
H _{3) 2} Cl and _{C 6 H 5 CH = CHCOC 6} H 4 O (CH 2) 6 S
A chemically adsorbed film was formed in the same manner as in Example 2 except that iCl ₃ was changed at a mixing ratio of 1: 0 to 0: 1. As a result of evaluating the obtained film, ClSi (CH ₃ ) ₂ OSi (CH ₃ ) ₂ O
As the concentration of Si (CH ₃ ) ₂ OSi (CH ₃ ) ₂ Cl decreases, the critical surface energy increases from 37 mN / m to 23 mN / m.
m. Further, the pretilt angle of the liquid crystal evaluated by assembling the liquid crystal cell was changed from 5 degrees to 87 degrees.

Example 5 CH ₃ as Chemically Adsorbed Material
CH ₂ C ^* HCH ₃ CH ₂ OCO (CH ₂ ) ₁₀ SiCl ₃ (where C ^* is an asymmetric carbon) and C ₆ H ₅ CH ＝ CHCOC ₆ H ₄ O
A chemical adsorption film was formed in the same manner as in Example 2 except that (CH ₂ ) ₆ SiCl ₃ was changed at a mixing ratio of 1: 0 to 1:20. When the obtained film was evaluated, CH ₃ CH ₂ C ^* HC
As the concentration of H ₃ CH ₂ OCO (CH ₂ ) ₁₀ SiCl ₃ decreases, the critical surface energy increases from 31 mN / m to 41 mN.
/ M. Further, the pretilt angle of the liquid crystal evaluated by assembling the liquid crystal cell was changed from 3 degrees to 0.1 degrees.

[0087]

As described above, according to the present invention, a chemically adsorbed film can be formed in a short time, with high efficiency, and with a uniform thickness. Further, a liquid crystal alignment film which is extremely thin and can control the alignment direction of the liquid crystal more accurately can be formed in a short time, with high efficiency, and with high uniformity.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a state of a chemical adsorption step in one embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing the state of the coating cleaning step.

FIG. 3 is a schematic longitudinal sectional view showing a state of molecules in the chemisorption film.

FIG. 4 is a schematic longitudinal sectional view showing a molecular state in a coating film after a chemical adsorption step in another embodiment of the present invention.

FIG. 5 is a perspective view showing a state of the exposure step.

FIG. 6 is a perspective view showing a state of a film after the exposure step.

FIG. 7 is a schematic longitudinal sectional view showing a molecular state in a film after the exposure step.

FIG. 8 is a schematic longitudinal sectional view showing a molecular state of a hydroxyl-rich film during a step of forming a hydroxyl-rich film according to still another embodiment of the present invention.

FIG. 9 is a schematic longitudinal sectional view showing a state of molecules in the hydroxyl group-rich coating.

[Explanation of symbols]

 1,11 glass substrate 2 chemical adsorption solution 3 washing solvent 4 chemical adsorption substance 5,5 'chemical adsorption film 6 polarizing plate 7,7' monomolecular film

Claims (17)

[Claims] 1. A chemisorption solution in which a silane-based chemisorption substance is dissolved in a nonaqueous organic solvent, wherein the nonaqueous organic solvent is a first nonaqueous organic solvent and the first nonaqueous organic solvent. A chemisorption solution comprising a mixed solvent containing a second non-aqueous organic solvent having a higher boiling point. 2. The chemical adsorption liquid according to claim 1, wherein the amount of the second non-aqueous organic solvent in the mixed solvent ranges from 0.1% by weight to 20% by weight. 3. The chemical adsorption liquid according to claim 2, wherein the amount of the second non-aqueous organic solvent in the mixed solvent is in the range of 1% by weight to 10% by weight. 4. The chemical adsorption liquid according to claim 1, wherein a difference in boiling point between the first non-aqueous organic solvent and the second non-aqueous organic solvent is in a range of 10 ° C. or more and 200 ° C. or less. 5. The chemical adsorption liquid according to claim 4, wherein a difference in boiling point between the first non-aqueous organic solvent and the second non-aqueous organic solvent is in a range of 20 ° C. or more and 100 ° C. or less. 6. The boiling point of the first non-aqueous organic solvent is 65.
The chemical adsorption liquid according to claim 1, which is at least 120C and not more than 120C. 7. The boiling point of the first non-aqueous organic solvent is 10
The chemical adsorption liquid according to claim 1, which is at least 0 ° C and not more than 120 ° C. 8. The boiling point of the second non-aqueous organic solvent is 15
The chemical adsorption liquid according to claim 1, which is at least 0 ° C. 9. The chemisorbed substance comprises at least one selected from a linear carbon chain and a siloxane-bonded chain, and at least one silyl group selected from the group consisting of a chlorosilyl group, an alkoxysilyl group and an isocyanatesilyl group. The chemical adsorption liquid according to claim 1, comprising: 10. The chemisorption solution according to claim 1, wherein the chemisorption solution is attached to a surface of a base material, and the chemisorption solution in the chemisorption solution attached to the base material is prepared. While the first non-aqueous organic solvent is preferentially evaporated and concentrated while leaving the second non-aqueous organic solvent, the end of the chemisorbed molecule in the chemisorption solution and the surface of the substrate are chemically treated. A method for producing a chemisorption film, comprising: removing the chemisorption solution remaining on the base material by washing the surface of the base material with a cleaning solvent. 11. The method according to claim 10, wherein a hydrophilic group is exposed on the surface of the substrate. 12. The chemical solution fixed to the surface of the base material by a liquid drainer that inclines the cleaned surface of the base material in a specific direction to remove a cleaning solvent attached to the surface of the base material. The method for producing a chemically adsorbed film according to claim 10, wherein molecules of the adsorbed substance are oriented in a draining direction. 13. The method according to claim 10, wherein the first non-aqueous organic solvent is a methyl silicone-based solvent. 14. The method according to claim 10, wherein the first non-aqueous organic solvent is a hydrocarbon solvent. 15. The solvent according to claim 1, wherein the second non-aqueous organic solvent is a methyl silicone solvent or a hydrocarbon solvent.
0. The method for producing a chemisorption film according to item 0. 16. The method according to claim 10, wherein the cleaning solvent contains substantially no water. 17. The chemical adsorption according to claim 10, wherein the cleaning solvent is a solvent containing at least one organic group selected from the group consisting of an alkyl group, a carbon fluoride group, a carbon chloride group and a siloxane group. Manufacturing method of membrane.