JP2007063304A - Liquid crystalline composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new liquid crystalline composition freely controlling physical properties in relation to the liquid crystalline composition useful in opto-electronics and photonics fields. <P>SOLUTION: The liquid crystalline composition comprises the following compounds: at least one kind of compound represented by general formula (1) (wherein, A<SP>1</SP>and A<SP>2</SP>represent each independently a substituted or an unsubstituted alkyl group or aromatic ring group substituted at any position of the 2-, 3-, 4- and 5-positions of the thiophene ring; B<SP>2</SP>represents a substituent having a positive value of Hammett's substituent constant σp; B<SP>1</SP>represents a substituent having a negative value of the Hammett's substituent constant σp; n1 and n2 represents each 0, 1 or 2; and both n1 and n2 are not 0); and at least one kind of compound having a photo-sensitive isomerizing group. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a novel liquid crystalline composition useful in the fields of optoelectronics and photonics.

  With the progress of an advanced information society, many attempts have been made to use optical technology for information transmission, processing, and recording. In such a situation, a liquid crystal capable of freely manipulating light by utilizing a change in the alignment state of molecules has attracted much attention as an extremely useful material.

  Typical examples of optical elements using liquid crystals include displays for displaying characters and images, but other spatial light modulators, dimming materials, optical compensators, nonlinear optical materials, etc. are known. Reflecting unique physical properties in addition to optical functions, it is expected to be applied to conductive materials, photoconductive materials, high-strength materials, tribological materials, electrorheological fluids, etc. Patent Document 1).

  In order to satisfy these specifications for such a wide variety of applications, the physical liquid crystal compounds can be mixed with other compounds to form a composition, allowing the physical properties to be freely controlled. is required.

  For example, the compounds described in Patent Documents 1 and 2 are expected to have a large non-linear optical effect, and some of them exhibit liquid crystallinity, but their handling is not always easy when considering application. Absent.

For example, when the heat resistant temperature of the support to be used is low, a composition having a lowered liquid crystal phase transition temperature is desirable. However, by trying to achieve this, the necessary liquid crystal phase may be lost. Often occurs. Therefore, development of a new liquid crystal composition capable of freely controlling physical properties from a new viewpoint has been desired.
JP 2004-143133 A JP-A-2005-63679 "Liquid Crystal Handbook" edited by Liquid Crystal Handbook Editorial Committee (Maruzen 2000)

  An object of the present invention is to provide a novel liquid crystal composition capable of freely controlling physical properties, particularly a phase transition temperature. Another object of the present invention is to provide a novel liquid crystalline composition useful in the fields of optoelectronics and photonics.

Means for solving the above problems are as follows.
[1] Liquid crystalline composition containing at least one compound represented by the general formula (1) and at least one compound having a photosensitive isomerization group:

式中、Ａ¹及びＡ²はそれぞれ独立して、チオフェン環の２，３，４，５位のいずれかの位置に置換している置換若しくは無置換の、アルキル基又は芳香族環基を表し；Ｂ²はハメットの置換基定数σｐ値が正の置換基を表し；Ｂ¹はハメットの置換基定数σｐ値が負の置換基を表し；ｎ１及びｎ２はそれぞれ０、１又は２を表すが、ｎ１及びｎ２が共に０になることはない。

Wherein, A ¹ and A ² are each independently substituted to have a substituted or unsubstituted at any position 2, 3, 4, 5-position of the thiophene ring, an alkyl group or an aromatic ring group B ² represents a substituent having a positive Hammett's substituent constant σp value; B ¹ represents a substituent having a negative Hammett's substituent constant σp value; n1 and n2 each represents 0, 1 or 2; , N1 and n2 are never 0.

[2] The composition of [1], wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2):

式中、―Ａｒ²―Ｄ²―Ｓ²―Ｐ²は４位又は５位に置換し、Ａｒ¹及びＡｒ²はそれぞれ独立して、単結合、又は置換若しくは無置換の、アルキル基若しくは芳香族基を表し；Ｄ¹は−Ｏ−、−Ｓ−又は電子供与性基を表し、Ｄ²は電子求引性基を表し、Ｓ¹及びＳ²は各々独立して二価の連結基を表し；Ｐ¹及びＰ²は各々独立して、炭素原子（Ｃ）、水素原子（Ｈ）、酸素原子（Ｏ）、窒素原子（Ｎ）、硫黄原子（Ｓ）及びハロゲン原子からなる群から選ばれる一種又は二種以上の原子のみから構成される置換基を表すが、Ｐ¹及びＰ²の少なくとも一つは重合性基を表す。

In the formula, —Ar ² —D ² —S ² —P ² is substituted at the 4-position or 5-position, and Ar ¹ and Ar ² are each independently a single bond or a substituted or unsubstituted alkyl group or aromatic. D ¹ represents —O—, —S— or an electron-donating group, D ² represents an electron-withdrawing group, and S ¹ and S ² each independently represents a divalent linking group. P ¹ and P ² are each independently selected from the group consisting of carbon atom (C), hydrogen atom (H), oxygen atom (O), nitrogen atom (N), sulfur atom (S) and halogen atom. Represents a substituent composed of only one kind or two or more kinds of atoms, and at least one of P ¹ and P ² represents a polymerizable group.

[3] The composition according to [1] or [2], wherein the compound having a photosensitive isomerization group is an azo compound.
[4] The composition of [3], wherein the azo compound is an azobenzene derivative.
[5] The composition of [4], wherein the azobenzene derivative is a compound represented by the following general formula C-3:

式中、Ａｒ¹¹及びＡｒ¹²はそれぞれ独立して、置換若しくは無置換の、炭素数６〜１０の芳香環又は炭素数５〜１０の複素環の残基を表し；Ｘ及びＹはそれぞれ独立して、単結合又は二価の連結基を表し；Ｒ¹及びＲ²はそれぞれ独立して、アルキル基、アルコキシル基、アルコキシカルボニル基、アルコキシカルボニルオキシ基、アルカノイル基、アルカノイルオキシ基、シアノ基、ニトロ基又はハロゲン基を表し；Ｒ³及びＲ⁴はそれぞれ独立して、ベンゼン環上に置換している、炭素数１〜６のアルキル基、炭素数１〜６のアルコキシル基又はハロゲン基を表し；ｎ及びｍはそれぞれ０〜３の整数を表し；ｏ及びｐはそれぞれ０〜４の整数を表し、ｑ及びｒはそれぞれ０〜４の整数を表す。

In the formula, Ar ¹¹ and Ar ¹² each independently represent a substituted or unsubstituted residue of an aromatic ring having 6 to 10 carbon atoms or a heterocyclic ring having 5 to 10 carbon atoms; X and Y are each independently R ¹ and R ² each independently represent an alkyl group, an alkoxyl group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, an alkanoyl group, an alkanoyloxy group, a cyano group, a nitro group R ³ and R ⁴ each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms or a halogen group substituted on the benzene ring; n and m each represents an integer of 0 to 3; o and p each represents an integer of 0 to 4, and q and r each represents an integer of 0 to 4.

[6] The composition according to [4] or [5], wherein the azobenzene derivative is a compound in which at least one substituent having an Es value of less than −0.5 is substituted on the benzene ring.
[7] The composition according to any one of [1] to [6], wherein the phase transition temperature of the liquid crystal phase can be changed by light irradiation.
[8] The composition according to any one of [1] to [7], wherein the compound of the general formula (1) has a polymerizable group.
[9] The composition according to any one of [1] to [8], wherein the compound of the general formula (1) has a plurality of polymerizable groups.

  In the present invention, the phase transition temperature of the composition is changed by causing a molecule having a light-sensitive isomerization group in the liquid crystal composition to cause stereoisomerization or structural isomerization by controlling light irradiation. It is possible. That is, according to the present invention, a liquid crystal composition capable of controlling physical properties such as a phase transition temperature in a wide range can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION

The liquid crystal composition of the present invention will be described in detail below.
In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
The present invention relates to a liquid crystal composition containing at least one compound represented by the general formula (1) and at least one compound having a photosensitive isomerization group. In the present invention, in addition to being able to control the phase transition temperature by changing the composition in the composition, by incorporating a compound having a photo-sensitive isomerization group in the composition, photosensitivity can be achieved by light irradiation. A molecule having a sex isomerization group undergoes stereoisomerization or structural isomerization to further change the phase transition temperature. As a result, the liquid crystal composition of the present invention can control the physical properties, particularly the phase transition temperature, over a wide range.
Hereinafter, various materials used for preparing the composition of the present invention will be described.

[Compound of general formula (1)]

In the formula, each of A ¹ and A ² independently represents a substituted or unsubstituted alkyl group or aromatic ring group substituted at any of positions 2, 3, 4, and 5 of the thiophene ring. B ² represents a substituent having a positive Hammett's substituent constant σp value; B ¹ represents a substituent having a negative Hammett's substituent constant σp value; n1 and n2 each represents 0, 1 or 2; , N1 and n2 are never 0.

The aromatic ring group represented by each of A ¹ and A ² is an aromatic carbocyclic group that is a residue of an aromatic carbocyclic ring or an aromatic heterocyclic group that is a residue of an aromatic heterocyclic ring. Also good. The aromatic ring contained in the aromatic ring group may be a single ring or a condensed ring, and in the case of a condensed ring, the condensed rings of carbocycles, heterocycles, and carbocycles and heterocycles Any of these may be used. The aromatic ring contained in the aromatic group is preferably an aromatic ring having 5 to 10 carbon atoms. Preferred examples of the aromatic ring group represented by each of A ¹ and A ² include 1,4-phenylene, thiophene-2,5-diyl, 2,6-naphthalene, thiazole-2,5-diyl, pyridine-2, 3-diyl, benzofuran-2,5-diyl, benzofuran-2,6-diyl, benzothiophene-2,5-diyl, benzothiophene-2,6-diyl, pyrimidine-2,5-diyl, pyrazine-2, 5-diyl, pyridazine-3,6-diyl and the like are included, and more preferable examples include 1,4-phenylene, 2,6-naphthalene and thiophene-2,5-diyl. In addition, the said aromatic ring group may have a substituent, As a preferable example, a C1-C8 alkyl group, an alkoxy group, a halogen atom, etc. are mentioned, More preferably, it is C1-C4. Alkyl groups (for example, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, etc.) and the like.

Either one of A ¹ and A ² (more preferably both) is preferably a substituted or unsubstituted aromatic ring group; either one of A ¹ and A ² is substituted or unsubstituted More preferred is substituted 2,6-naphthalene; A ¹ is 1,4-phenylene and A ² is 2,6-naphthalene, or A ¹ is 2,6-naphthalene and A ² is More preferred is 1,4-phenylene.

In the general formula (1), B ¹ represents a substituent having a negative Hammett's substituent constant σp value. Specifically, it represents an electron donating group such as a substituted amino group or an alkoxy group. Among these, a substituted amino group having a linear alkyl group as a substituent is particularly preferable, and a substituted amino group having a linear alkyl group having 1 to 8 carbon atoms as a substituent is more preferable.

In the general formula (1), B ² represents a substituent having a positive Hammett's substituent constant σp value. Specifically, the ester group (-COOR ^3), a sulfonyl group (-SO ₂ R ^3), sulfoxy group (-SO ^₃ R _3), or the like are preferable any of the substituents shown below, esters of these Groups are more preferred. However, R < ³ > represents a C1-C16 alkyl group and it is preferable that it is a C1-C12 linear alkyl group.

  Among the compounds represented by the general formula (1), a compound represented by the following general formula (2) is more preferable.

^{Wherein, -Ar 2 -D 2 -S 2 -P} 2 is substituted at the 4-or 5-position, independently Ar ¹ and Ar ² are each, a single bond, or a substituted or unsubstituted, alkyl group or aromatic D ¹ represents —O—, —S— or an electron-donating group, D ² represents an electron-withdrawing group, and S ¹ and S ² each independently represents a divalent linking group. P ¹ and P ² are each independently selected from the group consisting of carbon atom (C), hydrogen atom (H), oxygen atom (O), nitrogen atom (N), sulfur atom (S) and halogen atom. Represents a substituent composed of only one kind or two or more kinds of atoms, and at least one of P ¹ and P ² represents a polymerizable group.

In the formula (2), —Ar ² —D ² —S ² —P ² is preferably substituted at the 5-position.
As for the substituted or unsubstituted alkyl group or aromatic group represented by Ar ¹ and Ar ² , respectively, the substituted or unsubstituted alkyl group or aromatic group represented by A ¹ and A ² in the above formula (1), respectively. The preferred range is also the same. Ar ¹ and Ar ² are each preferably an aromatic ring having 5 to 14 carbon atoms (a ring having aromaticity including a heterocycle having 5 or more carbon atoms) or a biphenylene group, and a phenylene group, a naphthalene group, or More preferred is a biphenylene group. It is particularly preferable that one of Ar ¹ and Ar ² is a naphthalene group. Specifically, Ar ¹ is a phenylene group, and Ar ² is a naphthalene group, or Ar ¹ is naphthalene group and Ar ² is particularly preferably a phenylene group. When Ar ¹ and Ar ² each represent an aromatic ring having a substituent, examples of the preferred substituent include lower alkyl groups having 1 to 6 carbon atoms, more preferably methyl, ethyl, propyl, and isopropyl groups. , N-butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group and the like.

D ¹ in the general formula (2) represents an oxygen atom (—O—), a sulfur atom (—S—) or an electron donating group. As the electron-donating group, —NH—, a substituted amino group (—NR—, where R is a lower alkyl group having 1 to 6 carbon atoms, or a substituent represented by P ¹ —S ¹ — described later is particularly preferable. Preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group and a hexyl group), or a substituted amino group having a ring structure shown below,

Etc. are preferable, and an oxygen atom is particularly preferable.

In the general formula (2), D ² represents an electron attractive group. Preferred examples of the electron withdrawing group, carbonyl (-CO-), ester (-COO-), a sulfonyl group (-SO ₂ -), or a sulfonyloxy group (-SO ₃ -) electrons such as withdrawing An ester group (—COO—), a sulfonyl group (—SO ₂ —), or a sulfonyloxy group (—SO ₃ —) is preferable, and an ester group and a sulfonyloxy group are particularly preferable.

In the general formula (2), the linking group represented by S ¹ and S ² preferably has 2 to 12 carbon atoms, and more preferably 4 to 8 carbon atoms. S ¹ and S ² may have a ring structure, and when it has a ring structure, a cyclohexyl ring is preferable. Furthermore, an example of a preferable linking group is an alkylene group. The linking group may have one or more substituents. In this case, preferable substituents include a substituent having 1 to 4 carbon atoms and a halogen atom, and particularly preferably include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Moreover, when the carbon atom which has a substituent turns into asymmetric carbon, the configuration may be any of R, S, and its arbitrary mixture.

P ¹ and P ² in the general formula (2) each independently represent a substituent composed of one or more atoms selected from C, H, O, N, S and a halogen atom, At least one of P ¹ and P ² represents a polymerizable group. Only one of P ¹ and P ² may be a polymerizable group, but preferably both of P ¹ and P ² is a polymerizable group. Specific examples of P ¹ and P ² include a linear, branched or cyclic alkyl group (the hydrogen atom at any position may be substituted with a halogen atom), a polyethyleneoxy group, an acryloyloxy group, A methacryloyloxy group, a glycidyl group, a vinyloxy group, etc. are mentioned.

When P ¹ or P ² in the general formula (2) represents a polymerizable group, preferred examples include acryloyloxy group, methacryloyloxy group, glycidyl group, vinyloxy group, and acryloyloxy group and methacryloyloxy group. The group is particularly preferred.

  Preferred specific examples of the liquid crystal compound represented by the general formula (1) or (2) are shown below.

[Compounds having photosensitive isomerization groups]
In the present invention, the “photosensitive isomerization group” means, for example, a substance that causes stereoisomerization or structural isomerization by light, and preferably a substance that causes reverse isomerization by light of another wavelength or heat. It is. In general, those compounds that are accompanied by a color change in the visible range as well as structural changes are often well known as photochromic compounds. Specifically, azobenzene compounds, benzaldoxime compounds, Examples thereof include azomethine compounds, stilbene compounds, spiropyran compounds, spirooxazine compounds, fulgide compounds, diarylethene compounds, cinnamic acid compounds, retinal compounds, hemithioindigo compounds, and the like. Among these, an azo compound having an azo group is preferable.

  In addition, the light-sensitive isomerization substance that can be used in the present invention, that is, the compound having a functional group capable of photoisomerization may be a low-molecular compound or a polymer. In the case of a polymer, the light-sensitive isomerization group is located in the main chain. The same function can be demonstrated in the chain. In addition, the polymer may be a homopolymer or a copolymer, and the copolymerization ratio of the copolymer is appropriately set at a preferable value in order to appropriately adjust the polymer physical properties such as photoisomerization ability and Tg. Examples of the main chain of the polymer include polystyrene, malonic acid polyester, polyacrylate, polymethacrylate, polysiloxane, polyacrylamide, polymethacrylamide, polyoxyalkylene, terephthalic acid polyester, polyallylamine, polydicarboxylic acid amide, and polyurethane. , Polyoxyphenylene, polyvinyl alcohol, and polyco (vinylidene chloride) (methacrylate).

  Further, these compounds having a photoisomerizable functional group may be a liquid crystalline compound at the same time. That is, a functional group capable of photoisomerization may be included in the molecule of the liquid crystal compound. About these, Polymer, 41 (12), (1992) p884, "Chromic materials and applications" (published by CMC) p221, "Mechanochemistry" (Maruzen published) p21, "Polymer papers 147 vol.10" (1991) p771 and the like.

  In the present invention, an azobenzene derivative represented by the following general formula C-3 is preferably used as the compound having a photosensitive isomerization group.

In the above formula, Ar ¹¹ and Ar ¹² each represent a residue of an aromatic ring having 6 to 10 carbon atoms or a heterocyclic ring having 5 to 10 carbon atoms, which may have a substituent. Ar ¹¹ and Ar ¹² are each preferably a substituted or unsubstituted benzene ring, naphthalene ring, furan ring or thiophene ring residue, and particularly preferably a substituted or unsubstituted benzene ring residue. . X and Y each represent a single bond or a divalent linking group. X and Y are each preferably a single bond or a divalent linking group selected from the group consisting of C = C, C≡C, COO, OCO, CONH, NHCO, OCOO, OCONH and NHCOO, It is more preferable that R ¹ and R ² are substituents for Ar ¹¹ and Ar ¹² , respectively. R ¹ and R ² are each preferably an alkyl group, an alkoxyl group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, an alkanoyl group, an alkanoyloxy group, a cyano group, a nitro group, a hydroxy group or a halogen group, and an alkoxyl group In particular, an alkoxycarbonyl group, an alkoxycarbonyloxy group, an alkanoyloxy group, a cyano group, and the like are preferable. R ¹ and R ² preferably have a polymerizable group. Examples of preferred polymerizable groups include acryloyloxy group, methacryloyloxy group, vinyl group, vinyloxy group, glycidyl group and oxetane group. Furthermore, each of R ¹ and R ² may be linked to a polymer main chain to form a side chain polymer. R ³ and R ⁴ each represent a substituent on the benzene ring, and examples thereof include an alkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms, and a halogen group. n and m independently represent an integer of 0 to 3. Preferably, both are zero. o and p independently represent an integer of 0 to 4. Moreover, q and r show the integer of 0-4, respectively.

  Moreover, in this invention, a cinnamic acid derivative may be used as a compound which has a photosensitive isomerization group, and it is preferable to use the cinnamic acid derivative represented with the following general formula C-1 especially.

In the general formula C-1, Ar ¹¹ , Ar ¹² , R ¹ , R ² , R ³ , R ⁴ , X, Y, m, n, o, p, q, and r are each represented by the general formula C-3. It is synonymous with each inside.

  In the present invention, a styrylpyridine derivative may be used as the compound having a photosensitive isomerization group, and among them, a styrylpyridine derivative represented by the following general formula C-5 is preferably used.

In the general formula C-5, Ar ¹¹ , Ar ¹² , R ¹ , R ² , R ³ , R ⁴ , X, Y, m, n, o, p, q, and r are each represented by the general formula C-3. It is synonymous with each inside.

  In the present invention, an azobenzene derivative is preferably used as the compound having a photosensitive isomerization group, and among them, an azobenzene derivative in which at least one substituent having an Es value <−0.5 is substituted on the benzene ring. Are more preferable, and an azobenzene derivative in which a substituent having an Es value <−1.2 is substituted on each benzene ring is more preferable. In the low molecular weight compound, an azobenzene derivative having a total Es value of substituents on the benzene ring of less than −2.5 is preferable, and an azobenzene derivative of less than −2.9 is more preferable. The Es value is described, for example, in “Structure Activity Relationship between Drugs: Guidelines for Drug Design and Action Mechanism Research (Chemistry Domain Extra Number 122)” (1979, Nanedo) p124-126. Yes.

  Specific examples of the compound represented by the general formula C-3 are shown below as compounds having a photosensitive isomerization group that can be used in the present invention, but the compounds that can be used in the present invention are limited to these. is not.

  In addition, in the structure of the above exemplary compound, a compound in which the azobenzene skeleton is replaced with a cinnamic acid skeleton, and a compound in which the styrylpyridine skeleton is replaced are also exemplified compounds that can be used as the compound having a photosensitive isomerization group in the present invention. included.

  It is essential that the composition of the present invention contains at least one compound of the general formula (1) and at least one compound having a photosensitive isomerization group. As long as liquid crystallinity expression of the composition is not impaired, it may contain other compounds such as a polymerization initiator (light, heat), a chain transfer agent, a crosslinking agent, a surfactant and the like. The compound having the photosensitive isomerization group is preferably 0.3 to 50% by mass, and more preferably 1 to 15% by mass in the composition. Moreover, it is preferable that the compound represented by the said General formula (1) is 45.9-99.7 mass% in the said composition, and it is more preferable that it is 84.5-99 mass%.

  The composition of the present invention can be held on a substrate or between substrates to constitute part or all of the optical layer. Although the board | substrate used in this case is not limited, the thing excellent in flatness is preferable. For example, a metal substrate, a silicon substrate, a transparent substrate, etc. are mentioned. Preferable examples of the metal substrate include gold, silver, copper, aluminum and the like, and preferable examples of the transparent substrate include substrates such as glass and plastic (polyethylene terephthalate). An electrode part may be arranged on the substrate as necessary. Examples of preferable electrode parts include transparent electrode parts such as ITO and TCO, and gold electrode parts, but the substrate itself can be used as an electrode as necessary.

  An orientation part may be provided on the substrate or the electrode part. Various general methods can be adopted for the construction of the alignment portion, and preferred examples include methods using liquid crystal alignment films such as various polyimide alignment films and polyvinyl alcohol alignment films. Further, if necessary, an alignment treatment such as a surfactant treatment or an alignment treatment such as rubbing may be performed. In addition, a spacer, a sealant, or the like may be used on the substrate and between the pair of substrates as necessary.

  If necessary, an appropriate polymerization initiator, polymerization inhibitor, photosensitizer, crosslinking agent, polymerizable monomer, liquid crystal alignment aid and the like may be added to the optical layer. These additives do not necessarily have liquid crystallinity. The amount of the additive to be added is not particularly limited. However, the amount of additive used is preferably an amount that does not impair the liquid crystallinity.

  A well-known method is employ | adopted as a method of providing the said optical layer on a board | substrate. For example, a method in which the composition itself is applied, a method in which the composition is dissolved in a suitable solvent, and then dried are employed. As a coating method, known methods such as curtain coating method, extrusion coating method, roll coating method, spin coating method, dip coating method, bar coating method, spray coating method, slide coating method, printing coating method, etc. are adopted. The Further, a method of injecting the constituent component between a pair of substrates can be employed. As the injection method, a general method such as a dispenser method or a bell jar method is adopted.

  The physical properties of the composition of the present invention, mainly the phase transition temperature, can be changed by light irradiation. The light irradiation is performed under conditions sufficient to cause photoisomerization of the photosensitive isomerization group. The preferred range of the wavelength of light to be irradiated varies depending on the photosensitive isomerization group used, and is not particularly limited as long as it is a wavelength necessary for the isomerization. Preferably, the peak wavelength of light used for light irradiation is 200 nm to 700 nm, and more preferably the peak wavelength of light is 300 nm to 700 nm.

  The light source used for light irradiation is a commonly used light source such as a tungsten lamp, a halogen lamp, a xenon lamp, a xenon flash lamp, a mercury lamp, a mercury xenon lamp, a carbon arc lamp, or various lasers (eg, semiconductor laser, helium). Neon laser, argon ion laser, helium cadmium laser, YAG laser), light emitting diode, cathode ray tube, and the like. The light irradiation may be non-polarized light or polarized light. When using polarized light, it is preferable to use linearly polarized light. Furthermore, you may selectively irradiate only the light of a required wavelength using a filter, a wavelength conversion element, etc.

  As a method of irradiating light, a method of irradiating light from the upper surface or the back surface to the substrate perpendicularly or obliquely to the substrate is employed. The light irradiation wavelength and light source used are as described above.

  The composition of the present invention is used for production of a light-emitting element, a nonlinear optical material, an electro-optical material, a piezoelectric material, a display material, and the like.

  The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following specific examples.

[Examples 1 to 3]
A horizontal alignment cell (KSRP-05 / B111PINSS) having a 5 μm air gap in which a glass substrate having an ITO transparent electrode portion subjected to a rubbing treatment is applied in parallel with a polyimide (LX-1400 manufactured by Hitachi Chemical Co., Ltd.) thin film as an alignment film. The cells were respectively filled with the following compositions I to III in the voids of (. Etch Sea).
Next, the produced cell was placed on a heating device (hot stage FP82HT, central processor FP90, manufactured by Mettler), and installed so that it could be observed with a polarizing microscope (ECLIPSE E600W POL, manufactured by Nikon). When the O54 filter (made by HOYA) is installed on the illumination light source lens of the microscope and the light quantity is reduced to the minimum necessary for observation, and when the light quantity is maximized without installing a filter, the temperature is once heated to 100 ° C. Then, after confirming that it became an isotropic phase, the temperature was lowered at 1 ° C./min, and the temperature entering the smectic A phase was measured.

Composition I (Example 1)
90 mol% of exemplary compound 2 of general formula (1)
Illustrative compound A of a compound having a photosensitive isomerization group 10 mol%
Composition II (Example 2)
90 mol% of exemplary compound 2 of general formula (1)
Illustrative compound C of a compound having a photosensitive isomerization group 10 mol%
Composition III (Example 3)
90 mol% of exemplary compound 2 of general formula (1)
Illustrative compound F having a photosensitive isomerization group: 10 mol%

[Comparative Example 1]
A sample was prepared and measured in the same manner as in the above example using only the exemplified compound 2.

[Examples 4 to 6]
Samples were prepared and measured in the same manner as in Examples 1 to 3, except that the initial heating temperature was set to the isotropic phase temperature + 5 ° C.
Composition IV (Example 4)
90 mol% of exemplary compound 15 of general formula (1)
Illustrative compound C of a compound having a photosensitive isomerization group 10 mol%
Composition V (Example 5)
90 mol% of exemplary compound 38 of general formula (1)
Illustrative compound C of a compound having a photosensitive isomerization group 10 mol%
Composition VI (Example 6)
90 mol% of exemplary compound 39 of general formula (1)
Illustrative compound C of a compound having a photosensitive isomerization group 10 mol%
[Comparative Examples 2 to 4]
Sample preparation and measurement were carried out in the same manner as in Examples 4 to 6 except that Exemplified Compound 15 (Comparative Example 2), Exemplified Compound 38 (Comparative Example 3) and Exemplified Compound 39 (Comparative Example 4) were each used alone. went.

The evaluation results of Examples 1 to 3 and Comparative Example 1 are shown in Table 1.
The results of Examples 4 to 6 and Comparative Examples 2 to 4 are shown in Table 2.

  From the above results, it has been clarified that the compositions of Examples can change the phase transition temperature by changing the compound used in combination, and can further change the phase transition temperature by light irradiation. That is, it is clear that the phase transition temperature can be changed over a wide range by combining the compound represented by the general formula (1) and the compound having a photosensitive isomerization group.

Claims (7)

Liquid crystalline composition containing at least one compound represented by the general formula (1) and at least one compound having a photosensitive isomerization group:

In the formula, each of A ¹ and A ² independently represents a substituted or unsubstituted alkyl group or aromatic ring group substituted at any of positions 2, 3, 4, and 5 of the thiophene ring. B ² represents a substituent having a positive Hammett's substituent constant σp value; B ¹ represents a substituent having a negative Hammett's substituent constant σp value; n1 and n2 each represents 0, 1 or 2; , N1 and n2 are never 0. The composition according to claim 1, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2):

In the formula, —Ar ² —D ² —S ² —P ² is substituted at the 4-position or 5-position, and Ar ¹ and Ar ² are each independently a single bond or a substituted or unsubstituted alkyl group or aromatic. D ¹ represents —O—, —S— or an electron-donating group, D ² represents an electron-withdrawing group, and S ¹ and S ² each independently represents a divalent linking group. P ¹ and P ² are each independently selected from the group consisting of carbon atom (C), hydrogen atom (H), oxygen atom (O), nitrogen atom (N), sulfur atom (S) and halogen atom. Represents a substituent composed of only one kind or two or more kinds of atoms, and at least one of P ¹ and P ² represents a polymerizable group. The composition according to claim 1 or 2, wherein the compound having a photosensitive isomerization group is an azo compound. The composition according to claim 3, wherein the azo compound is an azobenzene derivative. The composition according to claim 4, wherein the azobenzene derivative is a compound represented by the following general formula C-3:

In the formula, Ar ¹¹ and Ar ¹² each independently represent a substituted or unsubstituted residue of an aromatic ring having 6 to 10 carbon atoms or a heterocyclic ring having 5 to 10 carbon atoms; X and Y are each independently R ¹ and R ² each independently represent an alkyl group, an alkoxyl group, an alkoxycarbonyl group, an alkoxycarbonyloxy group, an alkanoyl group, an alkanoyloxy group, a cyano group, a nitro group R ³ and R ⁴ each independently represents an alkyl group having 1 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms or a halogen group substituted on the benzene ring; n and m each represents an integer of 0 to 3; o and p each represents an integer of 0 to 4, and q and r each represents an integer of 0 to 4. The composition according to claim 4 or 5, wherein the azobenzene derivative is a compound in which at least one substituent having an Es value of less than -0.5 is substituted on the benzene ring. The composition according to any one of claims 1 to 6, wherein the phase transition temperature of the liquid crystal phase can be changed by light irradiation.