KR20130019750A - Comb-like poly(oxyethylene)/conjugated polymer blends and liquid crystal alignment layers using the same - Google Patents

Abstract

PURPOSE: A comb-like polyoxyethylene-based polymer/conjugate polymer blend is provided to stably maintain the alignment of a liquid crystal for long time, thereby being capable of increasing the efficiency of a liquid crystal display device. CONSTITUTION: A comb-like polyoxyethylene-based polymer/conjugate polymer blend comprises 100.0 parts by weight of a polymer indicated in chemical formula 1, and 10-90 parts by weight of a conjugated polymer which consists of one or more polymers selected from polymers indicated in chemical formula 2, 3, 4, or 5. A liquid crystal device comprises: an upper and lower substrate which faces each other; a transparent electrode formed on the upper and lower substrate; and a liquid crystal layer formed between the alignment film; and a liquid crystal alignment film which has a liquid crystal layer formed between the alignment films and is formed of the polymer blend.

Description

[0001] The present invention relates to a blend of comb-like poly (oxyethylene) / conjugated polymer blends and liquid crystal alignment layers using the same,

The present invention relates to a polymer blend for a liquid crystal alignment layer and a liquid crystal alignment layer using the polymer blend. More particularly, the present invention relates to a polymer blend containing comb polyoxyethylene polymer / conjugated polymer capable of forming a new liquid crystal alignment layer having an active color filter function Lt; / RTI >

Liquid crystal displays (LCDs), which are leading edge information display devices in the information age, are thin and light in thickness, and are applied to portable devices including notebook computers. Until now, many applications of LCD have been mostly personal such as notebook, monitor, and mobile phone. However, the demand for the improvement of the viewing angle characteristic and the moving picture response speed of the LCD is rapidly increasing as the use of the LCD is increased and the screen size is enlarged.

The control of the pretilt angle of the liquid crystal has attracted many researchers' interest both in terms of the technical aspects for improving the viewing angle characteristics and the moving response speed of the LCD and the academic and physical aspects for finding the physical and chemical fundamental factors of the surface of the liquid crystal In recent years, research results have been reported that continuously change the pretilt angle in the range of whole area. Various methods such as rubbing, light irradiation, ion beam irradiation, polymer blending, and micro / nano patterning have been used for controlling the pretilt angle, but most of the studies have been limited to conventional polyimide materials.

The polyimide-based material has been in a unique position as an orientation film due to its excellent thermal stability and liquid crystal alignment ability. However, the polyimide-based material is basically manufactured by reacting a diacid anhydride with a diamine compound to prepare a polyamic acid precursor, and then curing the polyimide precursor at a high temperature of about 200 ° C. or higher. And may adversely affect peripheral devices during the forming process and the high-temperature polyimide forming process.

In particular, current white light emitting diodes and organic light emitting diodes are mainly composed of two-wavelength white technology based on complementary color relation. However, in order to use the color filter function effectively, three wavelengths of red, green and blue Is required. Particularly, in the case of mobile phones and PDA LCDs, color reproduction rate and resolution are inferior. To solve this problem, an active color filter function is required to fabricate an LCD having an organic light emitting diode backlight source capable of realizing three independent wavelengths A new polymer blend for producing a liquid crystal alignment layer having a high refractive index is desired.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a novel polymer blend and a liquid crystal alignment layer including the polymer blend for producing a new liquid crystal alignment layer having an active color filter function.

In order to solve the above-mentioned problems, a polymer composition comprising 100 parts by weight of a polymer of Formula 1 below; And 10 to 90 parts by weight of a conjugated polymer composed of one polymer selected from the group consisting of a polymer of the following formula (2), a polymer of the following formula (3), a polymer of the following formula (4)

In the above formula (1), the range of n is from 8 to 18, the number average molecular weight is from 5,000 to 500,000, the dispersity is from 1.0 to 4.0,

In the above formula (2), the range of n is 4 to 12, the number average molecular weight is in the range of 5,000 to 200,000, the dispersion degree is in the range of 1.0 to 4.0,

In the above formula (3), the range of n is from 10 to 20, the number average molecular weight is from 10,000 to 300,000, the dispersion degree is from 1.0 to 4.0,

In the formula (4), the range of n is 4 to 18, the number average molecular weight is in the range of 50,000 to 1,000,000, the dispersion degree is in the range of 1.0 to 4.0,

The polymer blend for a liquid crystal alignment layer has a number average molecular weight in the range of 50,000 to 1,000,000 and a dispersion degree in the range of 1.0 to 4.0.

The present invention also provides a liquid crystal alignment layer comprising the polymer blend.

The present invention relates to an upper substrate and a lower substrate facing each other; A transparent electrode formed on the upper substrate and the lower substrate, respectively; An alignment layer formed on the transparent electrode; And a liquid crystal layer formed between the alignment layers, wherein the liquid crystal display element comprises the liquid crystal alignment layer of the present invention.

The method of manufacturing a liquid crystal alignment layer according to the present invention includes the steps of preparing a polymer solution by dissolving the polymer blend in a solvent; And applying the polymer solution onto a substrate and drying the polymer solution to form a polymer film.

The polymer blend for a liquid crystal alignment film of the present invention introduces a photoluminescence property of a comb-shaped polyoxyethylene conjugated polymer having a very low surface energy capable of stably maintaining the orientation of the liquid crystal for a long period of time without a curing process, Can be used as a liquid crystal alignment layer having an active color filter function. Since the liquid crystal alignment layer is maintained for a long period of time, it can be applied to various modes of liquid crystal display to improve driving efficiency of a liquid crystal display device.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments of the invention and, together with the description of the invention, It should not be construed as limited.
The left-hand lines in FIG. 1 indicate poly [oxy (decylsulfonyl) ethylenes (poly (oxy) (decylsulfonyl) ethylenes) according to the blend ratio of poly [oxy (X-ray photoelectron spectroscopy) of poly [oxy (decylsulfonylmethyl) ethylene] with respect to all the sulfur elements having a methyl group,
FIG. 2 is a polarized microscope photograph of the liquid crystal alignment behavior in a liquid crystal cell made of a poly (3-hexylthiophene) film according to Comparative Example 2. FIG.
3 is a polarized microscope photograph of the liquid crystal alignment behavior in a liquid crystal cell made of the polymer blend of Example 1. Fig.
4 is a polarized microscope photograph of the liquid crystal alignment behavior in a liquid crystal cell made of the polymer blend of Example 2. Fig.
5 is a polarized microscope photograph of a liquid crystal alignment behavior in a liquid crystal cell made of a polymer blend of Example 3. Fig.
6 is a polarized microscope photograph of the liquid crystal alignment behavior in a liquid crystal cell made of a polymer blend of Example 4. Fig.
FIG. 7 is a polarized microscope photograph of the liquid crystal alignment behavior in a liquid crystal cell made of poly [oxy (decylsulfonylmethyl) ethylene] film according to Comparative Example 1. FIG.

Hereinafter, the present invention will be described in detail with reference to the drawings. The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms and the inventor may appropriately define the concept of the term in order to best describe its invention It should be construed as meaning and concept consistent with the technical idea of the present invention.

The polymer blend for a liquid crystal alignment layer of the present invention comprises 100 parts by weight of a polymer represented by the following formula (1); And 10 to 90 parts by weight of a conjugated polymer consisting of one polymer selected from the group consisting of a polymer represented by the following formula (2), a polymer represented by the following formula (3), a polymer represented by the following formula (4) or a polymer represented by the following formula (5) or two or more compounds.

[Formula 1]

In the above formula (1), the range of n is from 8 to 18, the number average molecular weight is from 5,000 to 500,000, and the dispersion degree is from 1.0 to 4.0.

[Formula 2]

In the above formula (2), the range of n is 4 to 12, the number average molecular weight is in the range of 5,000 to 200,000, and the dispersion degree is in the range of 1.0 to 4.0.

(3)

In the above formula (3), the range of n is from 10 to 20, the number average molecular weight is from 10,000 to 300,000, and the dispersion degree is from 1.0 to 4.0.

[Formula 4]

In the above formula (4), the range of n is 4 to 18, the number average molecular weight is in the range of 50,000 to 1,000,000, and the dispersion degree is in the range of 1.0 to 4.0.

[Chemical Formula 5]

The number average molecular weight is in the range of 50,000 to 1,000,000 and the dispersion degree is in the range of 1.0 to 4.0.

The comb polyoxyethylene polymer represented by Formula 1 has a very low surface energy of 20-23 mN / m, and its surface characteristics are controlled by blending with a compatible polymer such as polystyrene and polymethylmethacrylate . In particular, the liquid crystal alignment film of the present invention using the polymer of the above formula (1) maintains the orientation of the liquid crystal stably for a long period of time without a curing process since the orientation property of the liquid crystal is induced by the simple coating process without the curing process, . Accordingly, the present invention can be applied to various liquid crystal modes such as TN (Twisted Nematic), IPS (In-Plane Switching), VA (Vertical Alignment) and OCB (Optically Compensated Bend) .

The polymers represented by the formulas (2) to (5) correspond to a conjugated polymer. These conjugated polymers can be applied to various fields such as a thin film transistor, a light emitting diode, an electrode, a photovoltaic cell, and a sensor because of their conductive, electroluminescent, and photoluminescent characteristics, and they can be used as a material for use as a color filter of a liquid crystal display have. Therefore, the liquid crystal alignment layer made of the polymer blend of the present invention including the conjugated polymer can be used as a liquid crystal alignment layer having an active type color filter function by introducing the photoluminescence property of the conjugated polymer.

In addition, the polymer blend for a liquid crystal alignment layer of the present invention may contain not only the conjugated polymers represented by the above Chemical Formulas 2 to 5 but also other polythiophene-based, polycarbazole-based, or polyphenylene vinylene-based conjugated polymers can do.

The liquid crystal alignment film of the present invention can be produced through the following steps.

First, the polymer blend is dissolved in a solvent to prepare a polymer solution.

As the solvent, various types of solvents capable of dissolving the polymer blend may be used. Such solvents include, but are not limited to, diethyl ether, chloroform, acetone, halogen-based alkane compounds, pyridine, tetrahydrofuran, chlorobenzene, and trifluorotoluene.

The polymer blend is dissolved in such a solvent to prepare a polymer solution. The concentration of the polymer solution can be varied in a range of 0.1 wt% to 10 wt% with respect to each solvent.

Thereafter, the polymer solution is coated on a substrate and dried to form a polymer film to produce a liquid crystal alignment film.

As the application method of the polymer solution, a commonly used coating method may be used, and spin coating, dip coating, roll coating, solution coating and the like may be used.

Then, the polymer film can be aligned to form a liquid crystal alignment film. The alignment treatment is for forming a uniform pattern on the polymer film to aid alignment of the liquid crystal. Such an alignment treatment method can be rubbing, polymer blending and micro / nano pattern formation, but is preferably used as a rubbing method.

The liquid crystal alignment layer of the present invention can be used as an alignment layer of a liquid crystal display (LCD). The liquid crystal panel of such a liquid crystal display (LCD) can be manufactured by sequentially forming a transparent electrode and an orientation film on upper and lower substrates facing each other, and injecting liquid crystal between the orientation films.

Hereinafter, the present invention will be described in detail with reference to Examples. However, the embodiments according to the present invention can be modified into various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Example

Example  One. Poly (3- Hexylthiophene ) Polymers 20 parts by weight  Preparation of Liquid Crystal Alignment Film Used

100 parts by weight of poly [oxy (decylsulfonylmethyl) ethylene] having a number average molecular weight of 68,000 and 20 parts by weight of a poly (3-hexylthiophene) polymer having a number average molecular weight of 50,000 were mixed with chloroform at a room temperature To prepare a polymer solution. The concentration of the polymer solution was set to 1 wt%.

The polymer solution was spin coated on the surface of the substrate at a rotation speed of 3000 rpm for 30 seconds and dried to prepare a liquid crystal alignment film.

Example  2-4. Poly (3- Hexylthiophene ) Polymers 40, 60, 80 Parts by weight  Preparation of Liquid Crystal Alignment Film Used

In the same manner as in Example 1, 40, 60 and 80 parts by weight of poly (3-hexylthiophene) polymer having a number average molecular weight of 50,000 was used to prepare a liquid crystal alignment film.

Comparative example  1. Poly [oxy Desil Sulphonyl methyl ) ≪ / RTI > Ethylene < RTI ID = 0.0 >

100 parts by weight of poly [oxy (decylsulfonylmethyl) ethylene] having a number average molecular weight of 68,000 was dissolved in chloroform at room temperature to prepare a polymer solution. The concentration of the polymer solution was set to 1 wt%.

The polymer solution was spin coated on the surface of the substrate at a rotation speed of 3000 rpm for 30 seconds and dried to prepare a liquid crystal alignment film.

Comparative example  2. Poly (3- Hexylthiophene ) Preparation of liquid crystal alignment film using polymer only

100 parts by weight of a poly (3-hexylthiophene) polymer having a number average molecular weight of 50,000 were mixed and then chloroform was dissolved in a solvent at room temperature to prepare a polymer solution. The concentration of the polymer solution was set to 1 wt%.

The polymer solution was spin coated on the surface of the substrate at a rotation speed of 3000 rpm for 30 seconds and dried to prepare a liquid crystal alignment film.

Test Example  One. XPS  And surface energy measurement

The XPS experiments on the liquid crystal alignment layers prepared in Examples 1-4 and 1-2 show the ratio of the sulfur to the sulfur of the thiophene on the surface of the liquid crystal alignment layer and are shown in FIG. Then, water and hexadecane were dropped on the liquid crystal alignment film to measure the contact angle, and the surface energy was calculated using the contact angle.

FIG. 1 is a graph showing the ratio of the blending ratio of the blend polymer to the sulfur element of poly [oxy (decylsulfonylmethyl) ethylene] with respect to all the sulfur in the liquid crystal alignment layer from the XPS experiment. ) Ethylene], the ratio of sulfur of poly [oxy (decylsulfonylmethyl) ethylene] rapidly increases up to 40 parts by weight, and thereafter the amount of increase thereof decreases. The change in surface energy is closely related to the chemical composition of the surface.

Test Example  2. Liquid crystal alignment test

The polymer solution prepared in Example 1-4 and Comparative Example 1-2 was spin-coated on rectangular ITO glass having a surface area of 2 × 2 cm ² at a speed of about 3,000 rpm for about 30 seconds to prepare an alignment layer. The liquid crystal cell was prepared by treating a small amount of a curing agent having 4.79 μm particle spacers on one side of the prepared alignment film and then pressing the other side of the alignment film, and after UV curing, 4'- n -pentyl-4-cyanobiphenyl (5CB) And the liquid crystal used was injected.

The orientation of the liquid crystal in the liquid crystal cell was confirmed by a polarizing microscope. FIGS. 2-7 are photographs corresponding to Examples 1-4 and Comparative Example 1-2 obtained through a polarization microscope experiment, respectively, and correspond to a conoscopic image.

FIG. 2 is a polarized microscope photograph of the liquid crystal alignment behavior in a liquid crystal cell made of a poly (3-hexylthiophene) film according to Comparative Example 2. FIG. It can be seen that the disordered horizontal liquid crystal array form appears.

3-6 are graphs showing the effect of the polymer blend of the poly [oxy (decylsulfonylmethyl) ethylene] and the poly (3-hexylthiophene) blend prepared in Example 1-4 Polarized light microscope photographs of the liquid crystal alignment behavior in a liquid crystal cell made of a film. A vertical type liquid crystal array shape appears.

 7 is a polarized microscope photograph of the liquid crystal alignment behavior in a liquid crystal cell made of poly [oxy (decylsulfonylmethyl) ethylene] film according to Comparative Example 1. Fig. A vertical type liquid crystal array shape appears.

2-7, the poly (3-hexylthiophene) in the case of the liquid crystal cell manufactured through the examples has disordered liquid crystal alignment characteristics of horizontal, but poly [oxy (decylsulfonylmethyl) ethylene] Type liquid crystal alignment characteristic. It can be seen that when the two polymers are blended, poly [oxy (decylsulfonylmethyl) ethylene] exhibiting a vertical liquid crystal alignment property exhibits a vertical liquid crystal alignment even when only 20 parts by weight is incorporated.

Claims (5)

100 parts by weight of a polymer of Formula 1 below; And
A polymer blend for liquid crystal alignment film comprising 10 to 90 parts by weight of a polymer of Formula 2, a polymer of Formula 3, a polymer of Formula 4, or a polymer selected from the following Formula 5 or two or more compounds :
[Formula 1]

In the above formula (1), the range of n is from 8 to 18, the number average molecular weight is from 5,000 to 500,000, the dispersity is from 1.0 to 4.0,
(2)

In Formula 2, the range of n has a value of 4 to 12, the number average molecular weight is in the range of 5,000 to 200,000, and the dispersion degree is in the range of 1.0 to 4.0,
(3)

In Formula 3, the range of n has a value of 10 to 20, the number average molecular weight is in the range of 10,000 to 300,000, and the dispersion degree is in the range of 1.0 to 4.0,
[Chemical Formula 4]

In Formula 4, n has a value of 4 to 18, a number average molecular weight of 50,000 to 1,000,000, a dispersibility of 1.0 to 4.0,
[Chemical Formula 5]

In Formula 5, the number average molecular weight is in the range of 50,000 to 1,000,000, and the dispersion degree is in the range of 1.0 to 4.0. 100 parts by weight of a polymer of Formula 1 below; And
It includes a polymer blend comprising 10 to 90 parts by weight of a conjugated polymer consisting of a polymer of Formula 2, a polymer of Formula 3, a polymer of Formula 4 or a polymer of Formula 5 Liquid Crystal Alignment Film:
[Formula 1]

In the above formula (1), the range of n is from 8 to 18, the number average molecular weight is from 5,000 to 500,000, the dispersity is from 1.0 to 4.0,
(2)

In Formula 2, the range of n has a value of 4 to 12, the number average molecular weight is in the range of 5,000 to 200,000, and the dispersion degree is in the range of 1.0 to 4.0,
(3)

In Formula 3, the range of n has a value of 10 to 20, the number average molecular weight is in the range of 10,000 to 300,000, and the dispersion degree is in the range of 1.0 to 4.0,
[Chemical Formula 4]

In Formula 4, n has a value of 4 to 18, a number average molecular weight of 50,000 to 1,000,000, a dispersibility of 1.0 to 4.0,
[Chemical Formula 5]

In Formula 5, the number average molecular weight is in the range of 50,000 to 1,000,000, and the dispersion degree is in the range of 1.0 to 4.0. An upper substrate and a lower substrate facing each other; Transparent electrodes formed on the upper substrate and the lower substrate, respectively; An alignment layer formed on the transparent electrode; And a liquid crystal layer formed between the alignment layers,
The liquid crystal display element according to claim 2, wherein the alignment layer comprises the liquid crystal alignment layer. 100 parts by weight of a polymer of Formula 1 below; And a polymer blend including 10 to 90 parts by weight of a conjugated polymer including a polymer of Formula 2, a polymer of Formula 3, a polymer of Formula 4, or a polymer of Formula 5 below. Dissolving in to prepare a polymer solution; And
Coating the polymer solution on a substrate, and drying the polymer solution to form a polymer film;
[Formula 1]

In the above formula (1), the range of n is from 8 to 18, the number average molecular weight is from 5,000 to 500,000, the dispersity is from 1.0 to 4.0,
(2)

In Formula 2, the range of n has a value of 4 to 12, the number average molecular weight is in the range of 5,000 to 200,000, and the dispersion degree is in the range of 1.0 to 4.0,
(3)

In Formula 3, the range of n has a value of 10 to 20, the number average molecular weight is in the range of 10,000 to 300,000, and the dispersion degree is in the range of 1.0 to 4.0,
[Chemical Formula 4]

In Formula 4, n has a value of 4 to 18, a number average molecular weight of 50,000 to 1,000,000, a dispersibility of 1.0 to 4.0,
[Chemical Formula 5]

In Formula 5, the number average molecular weight is in the range of 50,000 to 1,000,000, and the dispersion degree is in the range of 1.0 to 4.0. 5. The method of claim 4,
Wherein the solvent is at least one compound selected from the group consisting of chloroform, dichloromethane, acetone, pyridine, tetrahydrofuran, chlorobenzene, and dichlorobenzene, or a mixture of two or more thereof.

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