JPS6372784A - Ferroelectric polymer liquid crystal - Google Patents

Abstract

PURPOSE:To provide the title liq. crystal which exhibits a ferroelectric property even near ordinary temp., has a high speed of response to external factors, permits dynamic display, and is useful as a display element for a large image plane or a curved image plane and which comprises particular repeating units. CONSTITUTION:(Meth)acrylic acid (A) and an alkylene dihalide (B) (e.g., 1,10- dibromodecane) are heated in the presence of a catalyst in a solvent to conduct a reaction. The halogenoester thus obtd. is reacted with 2-methylbutyl 4'- hydroxybiphenyl-4-carboxylate (C) by heating in the presence of an alkali in a solvent, thereby obtaining a monomer of formula I (wherein R1 is H or CH3; n is 1-10; and X is a halogen). At least one monomer of formula I is reacted at 50-90 deg.C for 1-20hr in the presence of an initiator (e.g., azo bisisobutyronitrile), thereby obtaining the title liq. crystal having repeating units of formula II.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a novel ferroelectric polymer liquid crystal. More specifically, the present invention is applicable to the field of optoelectronics, particularly display elements for calculators and watches, electro-optical shutters, electro-optical apertures, optical modulators, optical communication optical path switching switches, memories, liquid crystal printer heads, variable focal length lenses, etc. useful as various electro-optical devices such as
A ferroelectric polymer liquid crystal that exhibits ferroelectricity even at room temperature, has a fast response speed to external factors, is capable of displaying moving images, and can be advantageously used as a display element for large screens or bendable screens. It is something.

[Conventional technology]

Conventionally, display elements using low-molecular liquid crystals have been widely used in digital displays such as calculators and watches.

In these fields of application, conventional low-molecular liquid crystals are usually used by sandwiching them between two glass substrates whose spacing is controlled on the order of microns. However, such adjustment of the gap has not been possible with large screens and curved screens. As a means to solve this difficulty, attempts have been made to polymerize liquid crystals and make them moldable (J, Polym, Sci, P.
o 1 ym, Letto, Ed, 13. 24
3 (1975), P.

lym, Bul 1. ．． 309.6 (1982),
(Japanese Unexamined Patent Publication No. 55-21479, etc.).

However, in these liquid crystal polymers, the response speed of changes in the amount of transmitted light to changes in external factors such as electric field is generally slow, and a satisfactory product has not yet been obtained.

In addition, the liquid crystal polymer disclosed in the above-mentioned publication has the disadvantage that the polymer itself does not exhibit liquid crystal properties at room temperature, and must be heated in a temperature range above the glass transition temperature and below the transparency temperature to become liquid crystal. have.

[Problem that the invention seeks to solve]

The present invention overcomes the drawbacks of conventional liquid crystal polymers, exhibits ferroelectricity even at room temperature, has a fast response speed to external factors, enables video display, and is suitable for large screens and bending. The purpose of this invention is to provide a polymeric liquid crystal that can be advantageously used as a screen display element.

(Means for Solving the Problems) As a result of intensive research to achieve the above object, the present inventors discovered that a new polymer having repeating units with a specific structure is suitable for the purpose. Based on this knowledge, we have completed the present invention.

That is, the present invention is based on the general formula % (1) (wherein R8 is a hydrogen atom or a methyl group, and n is 1 to 1O
The object of the present invention is to provide a ferroelectric polymer liquid crystal having a repeating unit represented by (an integer of ).

The present invention will be explained in detail below.

The number average molecular weight of the polymer liquid crystal of the present invention is 3,000 to 4.
The molecular weight is preferably in the range of 00,000.If the molecular weight is less than 3,000, the moldability of the polymer as a film or coating may be impaired;
If it exceeds 000, undesirable effects such as slow response speed may occur. A particularly preferable range of the number average molecular weight cannot be unconditionally defined because it depends on the type of R1, the value of n, the optical purity of the 2-methylbutyl group, etc., but usually s
,ooo~200,000.

The polymer liquid crystal of the present invention has a repeating unit represented by the general formula (1), in which R is a hydrogen atom or a methyl group, and n is an integer from 1 to 10, and this product has the following: For example, it can be suitably manufactured as follows.

That is, first, as shown in the following reaction formula, acrylic acid or methacrylic acid (n) and alkylene civalide (
III) to obtain the halogenoester (IV), and then react it with 4'-hydroxybiphenyl-4-carboxylic acid 2-methylbutyl ester (V) to obtain the monomer (Vl). .

R + R.

C1h FujiC-C0OH+X+CHz←-X -CHz
=C-COO+CHz←7X(n) (I[
[) (IV) (IV)
(V) (VI) (However, R and n have the same meanings as above, and X is a halogen atom) The reaction between the above acrylic acid or methacrylic M (n) and alkylene civalide (III) is as follows: It is carried out by heating at the desired temperature in a suitable solvent such as dimethylformamide in the presence of a catalyst such as tetramethylammonium hydroxide. The alkylene civalide (I[()) used in this case is preferably a bromine compound, such as methylene dipromide, 1,2-
Dibromoethane, 1,3-dibromopropane, 1,4-
Dibromobutane, 1.5-dibromopentane, 1.6-
Dibromohexane, 1.7-dibromohebutane, 1.8
-dibromooctane, 1.9-dibromononane, 1.1
Examples include 0-dibromodecane.

The 4'-hydroxybiphenyl-4-carboxylic acid 2-methylbutyl ester (V) is treated as an esterification catalyst in a suitable solvent such as benzene.
For example, in the presence of concentrated sulfuric acid or p-)luenesulfonic acid, 4'-hydroxybiphenyl-4-carboxylic acid and 2-
It is obtained by reacting (R)-2-methylbutanol or (S)-2-methylbutanol, which is an optically active form of methylbutanol, at a desired temperature.

The reaction between the halogenoester (IV) and 4'-hydroxybiphenyl-4-carboxylic acid 2-methylbutyl ester (V) is carried out using potassium hydroxide, hydroxide, etc. in a suitable solvent such as acetone. sodium,
It is carried out by heating to a desired temperature in the presence of an alkali such as potassium carbonate or sodium carbonate.

Next, one or more monomers represented by the general formula (Vl) thus obtained are polymerized to produce the polymer liquid crystal of the present invention, but in this case, the polymerization method For example, thermal radical polymerization, radical polymerization using an initiator, radical polymerization using ultraviolet rays or radiation, anionic polymerization using butyllithium or the like as an initiator can be employed.

Various initiators for radical polymerization are known, including benzoyl peroxide, peracetic acid, lauroyl peroxide,
A medium-temperature initiator such as azobisisobutyronitrile (AIBN) is preferably used.

Various methods such as bulk polymerization, slurry polymerization, and solution polymerization are known as polymerization methods, and any of these methods may be used.

Although the polymerization temperature varies depending on the polymerization method, especially the type of initiator, 50 to 90°C is usually suitable.

The polymerization time varies depending on other factors such as the polymerization temperature, but is usually 1 to 20 hours.

Molecular weight can be adjusted by adding a known molecular weight regulator and/or adjusting the concentration of initiator to monomer (usually 5% or less).

In the bulk polymerization method, the monomer and initiator are thoroughly mixed, the mixture is introduced between two glass substrates in the absence of oxygen, and the polymer is transferred between the substrates by heating. It is also possible to immobilize directly in a close contact state.

As the solvent in the case of slurry polymerization or solution polymerization, known inert solvents can be used, and aromatic solvents such as tetrahydrofuran, benzene, toluene, and xylene are particularly preferably used.

The polymer thus obtained can be used by being formed into a film by a known film forming method, such as a casting method, a T-die method, an inflation method, a calender method, or a stretching method. Film-like polymers can be used not only between two regular glass substrates, but also between large glass substrates, curved glass substrates, polyester films, etc., to create various devices such as liquid crystal displays, electro-optical shutters, and electro-optical apertures. It can be used in the field of optoelectronics. Furthermore, by applying a polymer solution dissolved in a suitable solvent to the surface of a substrate such as a glass substrate and evaporating the solvent, it is also possible to form a film in direct contact with the substrate surface.

It was confirmed from measurements of the phase transition temperature of the polymer liquid crystal of the present invention that a chiral smectic C-phase liquid crystal state is achieved at a temperature around room temperature, and that the response speed is extremely fast.

Next, the phase transition behavior and response speed of an example of the polymer liquid crystal of the present invention will be shown.

(Mn-6,300) Response speed 0.05 seconds (30℃, cell thickness 25μm) (Mn
= 42.000) Response speed 0.11 seconds (42°C, cell thickness 25 μm) (Mn
= 6,500) Response speed 0.09 seconds (60°C, cell thickness 25 μm) (Mn
=8.300) Response speed 0.18 seconds (71'C, cell thickness 25.crm)
However, here g is a glass state, Iso is an isotropic liquid,
SmA indicates a smectic A-phase liquid crystal state, and SmC11 indicates a chiral smectic C-phase liquid crystal state.

The polymeric liquid crystal of the present invention has numerous potential applications in the fields of integrated optics, optoelectronics, and information storage because it combines smectic phase liquid crystal with the properties of typical polymers that are easy to form. 0 For example, liquid crystal displays such as digital displays of various shapes, electro-optical shutters, electro-optic switches such as optical path switching switches for optical communications, electro-optical apertures, memory elements, optical modulators, liquid crystal optical printer heads, variable focal length It can be used as various electro-optical devices such as lenses.

The polymer liquid crystal of the present invention may be mixed with other polymers, or may be mixed with various inorganic and organic compounds including stabilizers and plasticizers, and additives such as metals, as necessary.
Improvements can be made by various processing methods well known in the art.

〔Example〕

EXAMPLES Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples in any way.

The structure of the obtained polymer was confirmed by NMR and IR1 elemental analysis, and the phase transition temperature was measured and the phase was confirmed by DSC and polarizing microscope, respectively.

Furthermore, the electric field response speed was measured as follows.

Measurement of response speed A polymer was sandwiched between two 20 x 10 fl ITO substrates, the thickness was adjusted to 25 μm with a spacer, and a DC electric field E was applied.
= 4X 10' V/m, and the response time of the change (0-90%) in the amount of transmitted light at that time was measured.

Example 1 Synthesis of acrylic acid 10-bromodecyl ester 0.2 mol (14,1 g) of acrylic acid and 0.22 mol (40,0 g) of tetramethylammonium hydroxide pentahydrate were dissolved in 300 mA' of DMF. After stirring for a period of time to make it homogeneous, 1,10-dibromodecane 0.4 mol (120 g)
was added and stirred for an additional 10 hours. Then, 300 mj of water was added to the reaction solution. was added and extracted with ether, and purified by column chromatography to obtain the bromoester (1
) 30.9 g (yield 53%) was obtained.

93 mmol (20 g) of 4'-hydroxybiphenyl-4-carboxylic acid and 4 mmol (41 g) of (S)-(-)-2-methylbutanol were dissolved in 2 ml of concentrated sulfuric acid.
In the presence of 150mj of benzene! Then, the reaction solution was concentrated and recrystallized from a toluene-hexane mixed solvent to obtain the hydroxyester compound (2) [mp
, 116.2-117.8°C, [α)2. '-+4.
35 (CHC1,)co26,Og (yield 98%) was obtained.

20 mmol (5.6 g) of the above-mentioned bromoester compound (1)
), hydroxyester (2) 18 mmol (5,1
A mixture of 72 mmol (10 g) of potassium carbonate and potassium carbonate was refluxed in acetone for 1'0 hours.Then, the reaction solution was filtered, concentrated, and recrystallized from ethanol to obtain monomer (3) [phase transition BehaviorCry""Iso"'
SmA” Cry, (α〕ν=”2.88 (CHC
13) 14.6 g (yield 52%) was obtained. (Cry
11' report (radical heavy A) of the polymer (radical polymer A) 1.01 mmol (500 μ) of the monomer (3) was added to TH
In F5mjj, reaction was carried out at 60°C for 12 hours using AlBN2.5N as a polymerization initiator.Then, the polymerization reaction product was fractionated and purified by column chromatography. 6
0%) was obtained.

The number average molecular weight Mn of this product was 6,300 (PS conversion), and the phase transition temperature was .

In addition, 1.01 mmol (500 ■) of monomer (3) was added to D
In 5 ml of MF, 2.5 mg of V-70 (manufactured by Wako Pure Chemical Industries, Ltd.) was used as a polymerization initiator and reacted at room temperature for 60 hours.Then, the same post-treatment as above was performed, and the number average molecular weight Mn was 42.0.
00 polymer (conversion rate: 44%) was obtained.

The phase transition temperature of this is The temperatures were 12°C, 51°C, and 115°C.

These results are shown in the attached table along with the response speed.

Example 2 Synthesis of acrylic acid 6-bromohexyl ester 0.2 mol (14,1 g) of acrylic acid, 0.22 mol (40,0 g) of pentahydrate IM of tetramethylammonium hydroxide and 1,6-dibromo Hexane 0.6 mol (146 g)
was reacted in 300 ml of DMF for 10 hours, and then treated in the same manner as in Example 1 to obtain the bromoester (1') 33
．． 8 g (yield 72%) was obtained.

20 mmol (4,7
g), hydroxyester compound (2) obtained in Example 1
A mixture of 18 mmol (5.1 g) and 72 mmol (Log) of potassium carbonate was refluxed in acetone for 10 hours, and then treated in the same manner as in Example 1 to obtain monomer (3').
[Phase transition behavior
"YU S m A 2" S m C-22LCry
, ((r) ” −+ 3.14 (CHC13)14
．． 8 g (yield 61%) was obtained.

± Yueni ■ Mamebosu 1.14 mmol (500 μ) of the above monomer (3') was reacted in THFSml with 2.8+ ng of AlBN as a polymerization initiator at 60°C for 15 hours, and then the same procedure as in Example 1 was carried out. A polymer of 370 cm (conversion rate: 74%) having a number average molecular weight Mn of 6.500 was obtained.

The phase transition behavior of this is Met.

These results are shown in the attached table along with the response speed.

Example 3 Synthesis of acrylic 2-bromoethyl ester Acrylic acid 0
．． 2 mol < 14.1 g), 0.22 mol of tetramethylammonium hydroxide pentahydrate (after heating at 40°, the same treatment as in Example 1 was carried out to obtain the bromoester form (1')
26.8 g (yield 75%) was obtained.

Synthesis of 20 mmol (3,6
g), hydroxyester compound (2) obtained in Example 1
A mixture of 18 mmol (5.1 g) and 72 mmol (10 g) of potassium carbonate was refluxed in acetone for 10 hours and then treated in the same manner as in Example 1 to obtain monomer (3''
) [Phase transition behavior (,ry""Cl s o"'CSm
A224Cr) 7% [α] Palm-3,48 (CHCI
s) 14.8 g (yield 70%) was obtained.

Synthesis of polymer 1.31 mmol (500 μ) of the monomer (3') was added to T
After reacting in HF5mjt with AIBN3.2w as a polymerization initiator at 60°C for 12 hours, the same treatment as in Example 1 was performed to obtain Polymer 3 with a number average molecular weight Mn of 8.300.
60■ (conversion rate 72%) was obtained.

The phase transition behavior of this is Met.

These results are shown in the attached table along with the response speed.

〔Effect of the invention〕

The polymer liquid crystal of the present invention exhibits ferroelectricity even at room temperature, has a fast response speed to external factors, and is capable of displaying moving images, and can also be advantageously used as a display element for large screens and bendable screens. It is useful as various electro-optical devices in the field of optoelectronics, and its industrial value is extremely large.

Claims (1)

[Claims] 1. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (In the formula, R^1 is a hydrogen atom or a methyl group, n is 1 to 1
A ferroelectric polymer liquid crystal having a repeating unit represented by (which is an integer of 0).