JPS62232409A - Organic polymer liquid crystal - Google Patents

Abstract

NEW MATERIAL:A polymer whose repeating unit has a structure of formula I [wherein R is CH3 or H, n is 0-12, provided that the group of formula II is O when n=0, X and Y are each H, CN or NO2 and Z is a 1-12 C alkyl or alkoxy group, an (alkyl-substituted) amino group, CN, NO2, trifluoromethyl, COOH, OH or an aldehyde group. EXAMPLE:A polymer whose repeating unit has a structure of formula III. USE:An organic polymer liquid crystal having a number-average MW of 2000-500,000, utility in an optical recording material for, e.g., thermorecording, a glass transition temperature higher than room temperature, capability of exhibiting a liquid crystal phase over a wide range of temperature, nonlinear optical functions and excellent transparency. PREPARATION:A compound of formula IV is addition-polymerized at -70-200<= in the presence (absence) of a solvent such as N,N- dimethylformamide.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Background of the Invention The present invention relates to an organic polymer 'X (hereinafter abbreviated as polymer liquid crystal) exhibiting liquid crystal behavior.

More specifically, it relates to a thermotropic liquid crystal that has a glass transition temperature that is significantly higher than room temperature, exhibits a liquid crystal phase above the glass transition temperature, and exhibits a liquid crystal phase over a wide temperature range.

Furthermore, the present invention relates to a polymeric liquid crystal that can highly align liquid crystal groups by utilizing orientation of liquid crystal groups in a liquid crystal phase by an electric field or a magnetic field.

In recent years, there have been remarkable developments in the application of liquid crystal materials, such as high-speed responsive displays that utilize electro-optical properties. Most of these liquid crystal substances are organic compounds with relatively low molecular weight.

On the other hand, research on polymer liquid crystals has recently been attracting attention, and in 1950, Elliot
) and Ambroae discovered that a chloroform solution of poly(γ-benzyl-L-glutamate) exhibits birefringence during the evaporation of the solvent, which marked the beginning of research into polymeric liquid crystals. Since then (Discussion Op The Faraday Society (D
isc, FaradaySoc, ) 9.246(
(1950) ) research has continued.

In particular, in 1968, DuPont discovered that fibers with high strength and high modulus could be spun from a poly(p-phenylene terephthalamide) liquid crystal alignment solution (B, P, 1).
, 283.064), this has inspired research into polymeric liquid crystals with the aim of developing fibers with high strength and high modulus of elasticity.

Regarding thermotropic polymer liquid crystals, in the 1970s, Jackson et al. discovered the thermotropic polymer liquid crystal properties of a random copolymer of poly(ethylene terephthalate) and poly(p-oxybenzoyl) (Journal of Polymer Science, Polymer Chemical Edition (J, Polym
er Sci, + PolymerChem, Ed.
) 14, 2093 (1976)). As a result, research into thermotropic polymeric liquid crystals became active with the aim of developing fibers with high performance mechanical properties through melt spinning.

On the other hand, it is also desirable to conduct research aimed at developing new properties and their applications, without focusing only on the mechanical properties of polymer liquid crystals.

For example, in a film with uniformly oriented polymer liquid crystals,
Thermorecording records data by irradiating it with laser light, reproduces it using light scattering caused by the disordered orientation, and erases the recording by orienting it with an electric field.
ding) (Abstracts of Papers, Third All-Union Conference Op-Liquid Crystals (Abstracts)
of papers at the 3-rdal
, t-Union Conference of L
iquid Crystats )+p 214. I
vanovo+ 1974).

In any case, in order to obtain highly oriented fibers, films, etc. from a molten state by utilizing the liquid crystal state of polymer liquid crystals, it is necessary to have a glass transition point higher than room temperature and a liquid crystal phase over a wide temperature range. Existing polymeric liquid crystals are useful.

In addition, in the sense of developing optically functional materials that utilize the alignment characteristics of polymeric liquid crystals, we aim to develop highly oriented liquid crystal groups in the liquid crystal phase by electric and magnetic fields, and to control this alignment by applying electric and magnetic fields. Polymer liquid crystals that can be fixed in a visible state are useful.

For example, if it is possible to impart a nonlinear optical function to the liquid crystal group of a polymer liquid crystal, to align it in the liquid crystal phase using an electric field, a magnetic field, etc., and to fix this orientation at room temperature, this oriented polymer liquid crystal can be It is extremely useful as a nonlinear optical material.

Based on the above-mentioned viewpoint, the present inventors have made earnest efforts to develop polymer liquid crystals having such characteristics. As a result, we have arrived at the present invention.

(2) Purpose of the present invention The present invention provides a polymeric liquid crystal whose glass transition point is higher than room temperature and whose liquid crystal phase exists over a wide temperature range.

Furthermore, the present invention provides a polymeric liquid crystal that can be oriented in a liquid crystal phase by an electric field or a magnetic field, and that can fix the orientation at room temperature in a state where the external field is removed.

Furthermore, the present invention provides a polymeric liquid crystal having a specific structure that has an effective nonlinear optical function in a liquid crystal group.

Further, the present invention provides a polymeric liquid crystal that is substantially transparent at the oscillation wavelength of a light source used in the visible to near-infrared region.

(3) Detailed description of the present invention 3-1) Structure of the polymer liquid crystal of the present invention The present invention provides polymer liquid crystals.

(Left below) -CH2-C- C=O(1) (CH2)n n=O -x R: Methyl group or hydrogen n: An integer from 0 to 12 However, when n=o, 10 (CH2 )n O-+! ,
,, −〇−.

X, Y: Hydrogen, cyan group or nitro group 2: Represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group, an amino group, a cyano group, a nitro group, a trifluoro group, a carboxyl group, a hydroxy group, or an aldehyde group. R, X, Y and 2 may each be the same or different.

R is a methyl group or hydrogen. That is, the main chain is a polymethacrylate skeleton or a polyacrylate skeleton. Selected based on the transparency of the polymer liquid crystal, glass transition point, etc. Methyl groups are preferred in order to set the glass transition point of the polymer liquid crystal high.

n is an integer from 0 to 12. It is also possible to use n=0, that is, the silver skeleton of the polymer and the liquid crystal group are directly bonded. At this time, it is assumed that formula (1) has the structure (1a). However, in relation to liquid crystal properties and alignment properties, -0-(CH=) acts as a spacer between the main chain skeleton and the liquid crystal group.
It is desirable to introduce n-0-. n=4 to 10 is preferable, n=5 to 8 is preferable, and n=6 is particularly preferable.

X and Y are hydrogen, a cyano group, or a =to group, preferably hydrogen or a cyano group, and particularly preferably a cyano group.

2 represents an alkyl group having 1 to 12 carbon atoms, an alkoxy group, an amino group, a cyano group, a nitro group, a trifluoro group, a carboxyl group, a hydroxy group, or an aldehyde group.

2 is preferably a methyl group, an amine group, an alkoxy group,
It is preferably a cyan group or a nitro group, more preferably a methyl group, an alkoxy group, or an amino group, and particularly preferably a methyl group.

The polymer liquid crystal of the present invention can exhibit higher nonlinear optical functions by suitably arranging electron-donating groups and electron-withdrawing groups in the stilbene skeleton.

The polymer liquid crystal of the present invention has a number average molecular weight of 2000 to s
It has a molecular weight of o o, o o o. Preferably 4000 to 200,000, more preferably 8
000 to 100.000.

3-2) Synthesis of polymer liquid crystal The polymer liquid crystal of the present invention can be obtained by addition polymerizing a compound represented by the following structural formula (2).

(Left below) CH=C C20 (CHz)n f2) C20 -X R is hydrogen or methyl group n is an integer from 0 to 12 (however, when n = 0, -0-(CHz)
)n O- is -0-)X, Y is hydrogen, cyano group or nitro group 2 is an alkyl group having 1 to 5 carbon atoms,
It includes an alkoxy group, an amino group, a cyano group, a nitro group, a trifluoro group, a carboxyl group, a hydroxy group, or an aldehyde group.

Preferred groups for R, X, Y, and Z correspond to the groups described as preferred in the above explanation of the structure of the polymer liquid crystal of the present invention.

Addition polymerization is usually carried out using a radical initiator.

A solvent may or may not be used, but N is usually used.

Solution polymerization is carried out using a solvent such as N-dimethylformamide.

The addition polymerization temperature is preferably -70°C to 200°C.

Further, addition by ionic polymerization can also be carried out when trying to control the stereoregularity of the main chain polymethacrylate skeleton or polyacrylate skeleton.

Apart from addition polymerization, the liquid crystal polymer of the present invention represented by formula +11 can also be obtained by adding a liquid crystal group to a polymer having the following structural formula (3) as an aa repeating unit.

Usually, the polymer liquid crystal of the present invention is synthesized by addition polymerization of compound (2).

3-3) Characteristics of polymer liquid crystal (i) Transition point The polymer liquid crystal of the present invention has at least two transition points, namely a glass transition point and a transition point to an isotropic fluid.

This transition point is confirmed, for example, in differential scanning calorimetry. This can be confirmed by an endothermic peak corresponding to the glass transition point during the temperature raising process and an endothermic peak corresponding to the transition to an isotropic fluid phase.

Further, under a polarizing microscope, changes in the structure accompanying the transition from the glass state to the liquid crystal phase and changes in the structure accompanying the transition from the liquid crystal phase to the isotropic fluid phase can be confirmed.

The polymer liquid crystal of the present invention preferably has a glass transition point of at least room temperature, more preferably at least 60°C, particularly preferably at least 8°C.
The temperature is 0°C or higher.

The glass transition point is related to the property of aligning liquid crystal groups in a liquid crystal state using an electric or magnetic field, lowering the temperature to below the glass transition temperature while applying the electric field or magnetic field, and fixing the orientation of the liquid crystal groups at room temperature. That is, if the glass transition point is lower than room temperature, it is difficult to fix the orientation at room temperature. Preferably 6
When it has a glass transition point of 0° C. or higher, more preferably 80° C. or higher, the orientation in the liquid crystal phase can be efficiently fixed at room temperature and storage is easy.

Fixing the orientation at room temperature means maintaining the orientation of the liquid crystal groups at room temperature in the absence of external forces such as an electric field or a magnetic field.

If the glass transition point is near room temperature, the orientation fixed below the glass transition temperature will be easily disturbed by an increase in temperature due to external energy.

On the other hand, if the glass transition temperature is too high, the temperature at which a liquid crystal phase is formed becomes high, requiring high temperatures for operations such as alignment, and causing problems of chemical deterioration.

Unless particularly heat resistance is required, the glass transition temperature is preferably 200°C or lower, more preferably 15°C or lower.
It is best to keep the temperature below 0°C.

The polymer liquid crystal of the present invention is a thermotropic liquid crystal that exhibits a liquid crystal phase above its glass transition temperature.

Most of the liquid crystal phases are formed as nematic liquid crystal phases, but in some cases, cholesteric liquid crystal phases and smectic liquid crystal phases are also formed.

The liquid crystal phase temperature range refers to the temperature range above the glass transition temperature and below the transition point to an isotropic fluid, and it is advantageous to have a wide liquid crystal phase temperature range. That is, operations such as alignment can be performed in a stable liquid crystal phase region.

The width of the liquid crystal phase temperature range is preferably 30°C or higher, more preferably 50°C or higher, and particularly preferably 80°C or higher.

A higher transition temperature to an isotropic fluid is preferable in the sense that the liquid crystal phase temperature range can be widened, but high temperatures are required to perform operations such as alignment in the liquid crystal phase region near the transition temperature. It is not preferable that the temperature is too high because of the problem of chemical deterioration in the liquid crystal phase region and isotropic flow region near the transition temperature.

Unless heat resistance is required, the transition temperature to an isotropic fluid is preferably 3000° C. or lower, more preferably 250° C. or lower.

(iD Orientation Characteristics The polymer liquid crystal of the present invention can be oriented by stretching or by an electric field or a magnetic field.

In particular, aligning the polarization direction of liquid crystal groups in one direction is
It is necessary to derive the second-order nonlinear optical characteristics, but
In such cases, it is effective to orient using an electric field or a magnetic field.

Orientation by an electric field is carried out by applying a DC voltage in the liquid crystal phase region. Applied voltage usually correlates with molecular weight. As the molecular weight increases, the applied voltage must also increase. For example, the polymer liquid crystal having a repeating unit of formula (1) of the present invention has a large molecular weight of 90,000.
．． When an applied voltage of about 5 volts/μm is applied, Williams domains are observed.

Usually, a voltage of 0.1 volt/μm or more is applied in the liquid crystal phase region to achieve orientation. Preferably 0.2-1
0vO1t/μm1, more preferably 0.4-7.0v
A voltage of olt/μm is applied.

0 to 20 below the transition temperature to isotropic fluid as the liquid crystal phase region
It is preferable to apply the voltage at a temperature lower than 0.degree.

In practice, it is preferable to apply a voltage from a temperature higher than the transition temperature to the isotropic fluid phase, and then cool the material while applying the voltage to enter the liquid crystal phase region.

By cooling the liquid crystal groups aligned by an electric field in the liquid crystal phase region to room temperature below the glass temperature while applying the electric field, the alignment can be fixed.

The degree of orientation fixation can usually be confirmed by checking the order parameter (S) defined by the following equation (4).

S=<3coo θ−1> (41 formula (4)
, the angle of deviation between the direction in which the long molecular axes of the liquid crystal groups are preferentially oriented and the long axis directions of the molecules of the individual liquid crystal groups is θ.
and <> indicates the average value over the entire space.

The order parameter (S) can be determined experimentally from measurements of refractive index and magnetic susceptibility, absorption dichroism in the ultraviolet, visible, and infrared wavelength regions, nuclear magnetic resonance absorption spectra, and X-ray diffraction measurements ( Z, Naturforsc
h, 16a, p 816 (1961)).

Furthermore, order parameters can also be determined from Seiko spin resonance spectra using a specially introduced label substance (Macromolecular Chemistry-Rapid Communication (Makromol)).

Chem, Rapid Commun, ) 3.2
81 (1982)).

For example, after the polymer liquid crystal of the present invention is subjected to an alignment treatment using an electric field or a magnetic field, the order parameter of the oriented polymer liquid crystal can be determined from absorption dichroism using the following equation (5).

S== (At"-")/(2A"+An) (5
) AII:i [absorption coefficient A1 in the direction parallel to the field direction; [The order parameter of the polymer liquid crystal can also be determined from the degree of orientation of the dye after mixing a dye with an absorption coefficient in a direction perpendicular to the direction of the field and performing the above-mentioned alignment treatment.

The polymer liquid crystal of the present invention preferably has an order parameter of 0.2 or more, more preferably 0.4 or more, particularly preferably 0.6 or more F, and can fix the orientation at room temperature.

Transparency of O The polymer liquid crystal of the present invention has a region that is substantially transparent to the oscillation wavelength of the light source used in the AF to near-infrared range.

3-4) Application of the polymer liquid crystal of the present invention The polymer liquid crystal of the present invention can be used alone or in the form of a mixture with other compounds.

In the polymer liquid crystal of the present invention, the liquid crystal group has a molecular structure that can have effective nonlinear optical susceptibility, and the liquid crystal group can be highly oriented in the liquid crystal phase region by an electric field or a magnetic field. Since the orientation can be fixed at room temperature, it can be applied as a second-order nonlinear optical material or a first-order all-in-one optical material.

The polymer liquid crystal of the present invention can be incorporated into various waveguides and applied as a waveguide-type double harmonic generation device or an optical switch device.

Of course, it is also possible to fix the polarization of the liquid crystal groups by applying an electric or magnetic field in the liquid crystal phase region and use this as a nonlinear optical material, but in this case, the glass transition point of the polymer liquid crystal used is rather low. In other words, it is better to choose a material that forms a liquid crystal phase at low temperatures.

Furthermore, it can also be used as a third-order nonlinear optical material or a second-order four-dimensional optical material without orienting the polarization of the liquid crystal group in advance.

Furthermore, it can be applied as an optical recording material such as thermo-recording, and applications that take advantage of its mechanical properties by forming it into fibers, films, etc. are also possible.

As described above, the polymer liquid crystal of the present invention can be used in a wide range of applications as optoelectronic materials and electronic materials by taking advantage of the fact that it is a polymer and has the ability to form a liquid crystal phase.

Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 A polymer liquid crystal having the following structure as a repeating unit will be used as an example of the polymer liquid crystal of the present invention, and its synthesis and properties will be explained.

(Left below) CWs -l-CH2-C→ C=O ■ (CH2)6 ``C=O C-CmiN (I Hs (1) Synthesis p-H)' Roxybenzoic acid and ω-chloroalcohol The reaction of 4-(ω-hydroxyhexyloxy)benzoic acid (
HABA-6) was synthesized.

The reaction between HABA-6 and methacrylic acid was carried out using p-)luenesulfonic acid as a dehydrating agent, hydroquinone as a polymerization inhibitor, and chloroform as a solvent until a predetermined amount of water was produced, resulting in 4-(ω-methacryloyloxy). xyloxy)
-benzoic acid (abbreviated as MABA-6) was synthesized.

The reaction of p-alkylbenzaldehyde and p-methoxybenzyl cyanide produces p-methoxy-p/-alkyl-α.
- Cyanostilbene (abbreviated as MAC3-n) was synthesized. MAC8-n was dissolved in acetic acid and refluxed in the presence of hydrobromic acid to obtain p-hydroxy-p'-alkyl-α-cyanostilbene (abbreviated as HAC8-m).

MABA-6 is converted to acid chloride with excess thionyl chloride. The obtained acid chloride was dissolved in tetrahydrofuran and reacted with HAC8-m, which was synthesized separately, to form a monomer with p-(4-(ω-methacroyloxybenzoic acid).
) 'p'-alkyl-α-cyanosterhenene was synthesized. The monomer was purified by repeated recrystallization in a chloroform-methanol mixed solvent to obtain a milky white solid.

Polymerization was carried out at 60° C. using N,N-dimethylformamide as a solvent and azobisin butyronitrile as a polymerization initiator.

The number average molecular weight of the obtained polymer was determined to be 840° by gel permeation chromatography.

In addition, the obtained polymer was analyzed by infrared absorption analysis, elemental analysis, NM
It was recognized from R etc. that it was a polymer having the above structure as one repeating unit.

(2) Properties of this polymer The thermal properties of this polymer were examined using a heated polarizing microscope, and the glass transition point was observed to be 106°C, and the transition point from liquid crystal phase to isotropic fluid phase to be 218°C. It was done. Moreover, the liquid crystal phase was recognized as nematic liquid crystal.

Using a differential scanning calorimeter, an endothermic peak corresponding to the glass transition point was observed at 118°C during the heating process, and a transition point to an isotropic fluid phase was observed at 206°C.

The polymer of the present invention was made into a tetrahydrofuran solution and cast into a film between At electrodes (with a spacing of 100 μfn) provided on a glass substrate.

In this way, a film of the polymer of the present invention was obtained between At electrodes on a glass substrate. Furthermore, both At'? A lead wire was attached to the l pole.

A heating cell was set on the stage of a heating polarizing microscope, and the above-mentioned glass substrate was placed on the heating cell and heated. 21
At 8° C. between crossed Nicols, the polymer of the present invention on a glass substrate turned into a dark field. After further heating to 225° C., a direct IT pressure of 500 V was applied between the At electrodes on the glass substrate.

While applying a DC voltage of 500 V between the At electrodes on the glass substrate, heating was stopped and allowed to cool.

The polarized light absorption spectrum in the ultraviolet region of the polymer of the present invention on a glass substrate cooled to room temperature was measured.

The order of the polymer of the present invention after the orientation treatment is determined from the absorption spectrum in the ultraviolet region of light polarized in a direction parallel to the direction of the electric field and the absorption spectrum in the ultraviolet region of light polarized in the direction perpendicular to the direction of the electric field. The parameter was found to be 0.4.

Furthermore, the polymer of the present invention has a particle diameter of 400 nm to 1l100n.
It was substantially transparent in the visible to near-infrared region.

Patent applicant Mitsubishi Yuka Co., Ltd. agent Patent attorney Hidetoshi Furukawa (and one other person) Procedural amendment (voluntary) July 29, 1985 L Indication of case 1985 Patent Application No. 75097 2 Title of the invention Organic polymer liquid crystal λ Relationship with the case of the person making the amendment Patent applicant 2-5-2 Marunouchi, Chiyoda-ku, Tokyo (605) Mitsubishi Yuka Co., Ltd. (2 others) Unrepresented 1 Inventions increased by amendment Number 0 & Column 7 of the scope of claims and detailed description of the invention in the specification to be amended, contents of the amendment (1) The scope of claims shall be as shown in the attached sheet.

(2) On page 9, line 4, page 10, last line, and page 13, line 2, write “
The phrase "amino group" is replaced with "amino group (including alkyl-substituted amino group)".

Attachment: Claims (1) Organic polymer liquid crystal -C-C-C-C=O consisting of a polymer having the following structural formula (1) as a repeating unit and having a number average molecular weight of 2000 to soo, o o o R: Methyl group or hydrogen n: An integer of 0 to 12. However, when n=o, -〇-(CH2)n-0- is -〇-.

X: hydrogen, cyano group, or nitro group Y: hydrogen, cyano group, or nitro group z: alkyl group having 1 to 12 carbon atoms, alkoxy group,
amino group (including alkyl-substituted ξ) group), cyan group,
Represents a nitro group, trifluoromethyl group, carboxyl group, hydroxy group or aldehyde group. R, XXY and Z may be the same or different.

(2) In structural formula (1), X is a cyano group, Y is hydrogen,
The organic polymer liquid crystal according to claim 1, wherein 2 is a methyl group.

Claims (2)

[Claims] (1) Organic polymer liquid crystal consisting of a polymer having the following structural formula (1) as a repeating unit and having a number average molecular weight of 2,000 to 500,000 ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (1) However, R: methyl group or hydrogen n: an integer from 0 to 12. However, when n=0, -O-(CH_2)_n-O- is -O
−. X: hydrogen, cyano group or nitro group Y: hydrogen, cyano group or nitro group Z: alkyl group having 1 to 12 carbon atoms, alkoxy group, amino group, cyano group, nitro group, trifluoro group, carboxyl group, hydroxy group Or represents an aldehyde group. R,
X, Y and Z may be the same or different. (2) In structural formula (1), X is a cyano group, Y is hydrogen,
The organic polymer liquid crystal according to claim 1, wherein Z is a methyl group.