JP4781803B2 - Orientation control method of organic microcrystal - Google Patents

Description

  The present invention relates to a method for controlling anisotropic orientation of microcrystals of an organic compound (hereinafter referred to as organic microcrystals) with respect to three orthogonal crystal axes, and an organic microcrystal orientation dispersion produced by the method. is there. More specifically, a method of inducing anisotropic orientation with respect to three crystal axes of an organic microcrystal by simultaneously applying a magnetic field and an electric field, and an anisotropic crystal with respect to three orthogonal crystal axes produced by the method. The present invention relates to an organic microcrystalline dispersion characterized by being oriented and dispersed and fixed in a polymer dispersion medium.

  Dispersion materials in which fine crystals of organic compounds such as organic dyes and organic pigments are dispersed have electrical, magnetic, and optical anisotropy and isotropic properties of the entire dispersion system. It is expected to be used as various optical and display materials such as magnetic materials, color filters, organic second-order nonlinear optical materials, and three-dimensional displays.

  The inventors of this application pay attention to organic microcrystal dispersion using a second-order nonlinear optical crystal, and display a three-dimensional image based on a completely new principle of using the second harmonic due to the second-order nonlinear optical effect. And a three-dimensional display (Patent Document 1).

  In addition, as a material for polarizing color filters, we focused on organic microcrystal dispersions of organic dyes and organic pigments, and a new dispersion of organic dyes or organic pigment fine particles that can improve transmittance and polarization function. A polarizing color filter and a manufacturing method thereof have been proposed (Patent Document 2).

  Furthermore, microcrystals of organic dyes or organic pigments are mixed with a dispersion medium for fixing an alkylacrylic acid monomer or oligomer which may have a substituent to induce anisotropic orientation by applying a magnetic field or an electric field. The manufacturing method of the organic microcrystal orientation dispersion characterized by fixing by photocuring was proposed (patent document 3).

  In general, organic crystals such as organic dyes and organic pigments have three-dimensional anisotropy because organic molecules are regularly arranged with a three-dimensional periodicity. ing. Therefore, in order to efficiently extract physical properties as external signals, it is important to control the orientation of individual microcrystals that are not normally aligned (FIG. 1).

  Conventionally, as a method for controlling the orientation of microcrystals, anisotropy is controlled by applying an electric field (Patent Document 4, Non-Patent Documents 1 to 3) or a magnetic field (Patent Documents 5 to 8, Non-Patent Document 4). The technique is known (FIG. 2).

  The orientation control by applying an electric field utilizes a phenomenon in which a microcrystal is oriented along an electric field by applying an electric field when the crystal has an electric dipole.

  The orientation control by applying a magnetic field utilizes a phenomenon in which a crystal is oriented by a repulsive action between an external magnetic field and an induced diamagnetic magnetic dipole when a diamagnetic magnetic dipole is induced in the crystal by an external magnetic field.

However, these methods of applying an electric field or magnetic field can only align the orientation of the crystal with respect to one of the three crystal axes orthogonal to each other. In all cases, the technique for realizing the control of the crystal orientation was still unexplored.
JP 2003-287711 A Japanese Patent Application No. 2002-276179, Japanese Patent Application Laid-Open No. 2004-109951 Japanese Patent Application No. 2004-245947, Japanese Patent Application Laid-Open No. 2005-171221 Japanese Patent Application No. 2004-103039, Japanese Patent Application Laid-Open No. 2005-288214 Japanese Patent Application No. 7-99895, Japanese Patent Application Laid-Open No. 8-213233, Japanese Patent No. 3576263 Japanese Patent Application No. Hei 8-134320, Japanese Patent Application Laid-Open No. 9-297330, Japanese Patent No. 3577388 Japanese Patent Application No. 2003-349352, Japanese Patent Application Laid-Open No. 2005-113205 Japanese Patent Application No. 2005-76110, Japanese Patent Application Laid-Open No. 2005-297556 S. Fujita, H. Kasai, S. Okada, H. Oikawa, T. Fukuda, H. Matsuda, SK Tripathy, H. Nakanishi, Jpn. J. Appl. Phys. 1999, 38, L659-L661. H. Oikawa, S. Fujita, H. Kasai, S. Okada, SK Tripathy, H. Nakanishi, Colloids and Surfaces A: Physicochem. Eng. Aspects 2000, 169, 251-258. T. Onodera, M. Yoshida, S. Okazoe, S. Fujita, H. Kasai, S. Okada, H. Oikawa, H. Nakanishi, Int. J. Nanoscience 2002, 1, 737-741. Y. Kaneko, T. Fukuda, T. Onodera, H. Kasai, S. Okada, H. Oikawa, H. Nakanishi, H. Matsuda, Jpn. J. Appl. Phys. 2003, 42, L1343-L1345.

Problems to be solved by the invention

  The invention of this application was made based on the above background, and is expected to be used as a dielectric, magnetic material, color filter, organic second-order nonlinear optical material, and various optical / display materials. A method for controlling anisotropy with respect to three orthogonal crystal axes of an organic microcrystal, which is important for producing a new organic microcrystal orientation-dispersed copolymer comprising a microcrystal dispersion of an organic compound such as a dye or an organic pigment It is an issue to provide.

  The invention of this application is to solve the above-mentioned problem. First, by applying a magnetic field and an electric field simultaneously to an organic microcrystal dispersion in which microcrystals of an organic compound are dispersed in a dispersion medium. An organic microcrystal orientation control method is provided, wherein the organic microcrystal is anisotropically oriented with respect to three orthogonal crystal axes.

  Control of the orientation of the induced microcrystal by applying an electric field is considered to be based on the electric dipole of the crystal, but it is assumed that the origin is due to the molecular or ionic polarization of the organic molecules constituting the crystal or the surface of the microcrystal. Is done.

  Orientation control by applying a magnetic field is thought to be based on an induced diamagnetic magnetic dipole, but it is assumed that its origin is a magnetic dipole induced by the flow of pi electrons in an aromatic ring or unsaturated bond in an organic molecule. The

  Therefore, in general, these two dipoles are independent of each other in the crystal, and by controlling the two external fields of the external electric field and the external magnetic field, the orientation of the microcrystal is controlled with respect to all three orthogonal crystal axes. (FIG. 3).

  The organic microcrystal orientation control method according to the present invention is more specifically, by simultaneously applying a magnetic field and an electric field to an organic microcrystal dispersion system in which microcrystals of an organic compound are dispersed in a dispersion medium, The crystal is anisotropically oriented with respect to three orthogonal crystal axes.

  Further, the organic microcrystalline orientation dispersion according to the present invention is a polymer in which a microcrystal of an organic compound is anisotropically oriented with respect to three orthogonal crystal axes by simultaneously applying a magnetic field and an electric field, and serves as a dispersion medium. It is characterized by being distributed and fixed to.

  According to the invention of this application as described above, it consists of a dispersion system of organic dyes or organic pigment fine particles useful as dielectrics, magnetic substances, color filters, organic second-order nonlinear optical materials, and various optical / display materials. A method for controlling the orientation of three orthogonal crystal axes of organic microcrystals necessary for the production of a new organic microcrystal orientation dispersion is provided.

  As described above, the organic microcrystal orientation control method of the invention of this application is induced by simultaneously applying a magnetic field and an electric field to a microcrystal dispersion system of an organic compound as schematically illustrated in FIG. The anisotropic orientation effect of microcrystals is used.

  An embodiment of the invention of this application having such characteristics will be described below.

  First, in the invention of this application, the organic compound is not particularly limited as long as it is crystalline, but preferably an organic dye or organic pigment, for example, a dye or pigment for a color filter used in a liquid crystal display, or a second-order nonlinear optical material. Various dyes may be used, including dyes for use in organic electroluminescence devices, luminescent dyes for use in organic electroluminescent elements, and fluorescent dyes. Preferably, all styrylpyridinium dyes such as DAST, polydiacetylenes, poly 1,6 mono-di (n-carbazoyl) -2,4-hexadiene: Poly (DCHD), polycyclic aromatic compounds (anthracene, tetracene, Pentacene, coronene), phthalocyanines, porphyrins and the like. Nanosized microcrystals of these organic dyes and organic pigments, that is, in the invention of this application, generally, microcrystals having a size of several nanometers (nm) to 1 micron (l000 nm) or less are contained in the dispersion medium. Although a stably dispersed colloidal dispersion is used, a crystal larger than 1 micron may be used as long as the dispersed state can be maintained even for a short time, and preferably a size of 1 to 200 microns.

  The dispersion medium is not particularly limited as long as it can disperse the fine crystals of the organic compound without dissolving it, but an organic solvent having a low dielectric constant is preferable. For example, hydrocarbon solvents such as decalin and liquid paraffin are mainly used. Moreover, the medium for fixation demonstrated below may be sufficient. That is, when the organic microcrystal orientation dispersion is dispersed and fixed in a dispersion medium, a fixing medium is used. As the immobilization medium in this case, a monomer or oligomer of alkylacrylic acid which may have a substituent, and among them, a medium which is crosslinked and cured by light is used. Specific examples of the monomer include all acrylic esters, for example, octylacrylic acid, laurylacrylic acid, laurylmethacrylic acid or the like having an alkyl group having 7 or more carbon atoms. Alkyl acrylic acid, alkylacrylic acid or alkylmethacrylic acid having various substituents such as diacrylic acid such as ethyleneglycoxyacrylic acid and fluorinated alkylacrylic acid, halogen atoms and alkoxy groups are desirable. Here, by using an alkylacrylic acid monomer in combination with, for example, a diacrylic acid monomer derivative, the photocuring rate is improved and the immobilization is efficiently performed. The amount of the diacrylic acid monomer derivative used is preferably several percent with respect to the alkylacrylic acid monomer, and preferably 1 to 2%, for example. As described above, these dispersion media are mixed using a photopolymerization initiator with a range and type that do not destroy the dispersion state in the dispersion.

  Examples of the photopolymerization initiator include azo compounds such as 2,2, -azobisisobutyronitrile (AIBN), peroxides such as benzoyl peroxide (BPO), trichloroacetophenone, and tris (trichloromethyl) -5. -Polyhalogen compounds such as triazine, acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ketones such as benzoin alkyl ether and benzophenone, and organic metals such as bispentadiethyltitanium di (bentafluorophenyl) Compounds.

  In the invention of this application, a magnetic field and an electric field are simultaneously applied while being dispersed in such a dispersion medium to induce anisotropic orientation in the microcrystal. Or in the mixed state as above. A magnetic field and an electric field are simultaneously applied to induce a forceless orientation in the microcrystal to solidify the fixing medium. Thereby, a polymer which is transparent after curing and excellent in processability can be obtained.

  Regarding the magnetic field in this case, the magnetic field direction and the magnetic field strength may be appropriate, and the larger the magnetic field strength, the better. Since the effect of crystal orientation depends on the size of the induced magnetic dipole of the crystal, generally, the larger the crystal, the smaller the required magnetic field strength. For example, in the case of a crystal of a size of several hundred microns, a magnetic field of about several tens of Tesla using a superconducting magnet is applied to a crystal of 1 micron or less. To do.

  As the electric field, either alternating current (AC) or direct current (DC) may be applied, but the degree of crystal orientation increases as the electric field strength increases. In the case of direct current, the electric field strength between the electrodes is preferably 1 to 3 KV / cm, and in the case of alternating current, the electric field strength is 1 to 10 KV / cm and the frequency is 10 to 10000 Hz, but is not limited thereto.

  According to the invention of this application as described above, an orientation control method for organic microcrystals is characterized in that crystals are anisotropically oriented with respect to three orthogonal crystal axes by simultaneously applying a magnetic field and an electric field. An organic microcrystal orientation dispersion characterized by being anisotropically oriented with respect to three crystal axes and being dispersed and fixed in a polymer as a dispersion medium is realized.

  The organic microcrystalline orientation dispersion provided by the invention of this application provides an unprecedented anisotropic material having anisotropy with respect to three orthogonal crystal axes. That is, the inventors of the present application have found that the above-mentioned organic microcrystalline alignment dispersion can be produced as a result of intensive studies on this anisotropic material, and have reached the present invention. This anisotropic material, for example, makes it possible to efficiently extract physical properties from the directions of three orthogonal crystal axes of an organic crystal, which has been difficult until now.

  Therefore, examples will be shown below, and the embodiments of the invention will be described in more detail. Of course, the invention is not limited by the following examples.

  The microcrystalline dispersion of DAST (trans-4- [4- (dimethylamino)] stilbezolium-p-toluenesulfonate) is prepared by adding 0.05 ml of 5 mM DAST ethanol solution containing 5 mM n-dodecyl-trimethyl ammonium chloride to 5 ml lauryl acrylate. It was made by pouring into the monomer with stirring (Figure 4). The orientation behavior of DAST microcrystals was observed using a spectroscopic technique while both an electric field (E) and a magnetic field (B) were applicable. FIG. 5 shows a simplified diagram of the measurement cell. In order to observe the orientation behavior, polarized light (0 deg.) Parallel to the direction of the magnetic field is used, and both the magnetic field and electric field are forked. (1) [Fig. 5 (a)] and the magnetic field are forked. In the case of an arrangement in which the magnetic field is applied perpendicularly to the magnetic field (2) The polarization spectrum of [Fig. 5 (b)] or the polarized light perpendicular to the direction of the magnetic field (90 deg.) Is used. Case (3) [Fig. 5 (a)] and the case where the magnetic field is a Forked arrangement and the electric field is applied perpendicular to the magnetic field (4) [Fig. 5 (b)] The polarization spectrum was measured. For example, the orientation behavior (of DAST crystallites) was observed by applying a magnetic field of 2T at maximum and an electric field of 0.2 kV / 8 mm at maximum DC.

  If any orientation of the organic nanocrystal due to an external field occurs, a change occurs in the visible ultraviolet polarization spectrum. Using this point of view, we measured the visible ultraviolet polarization spectrum of nanocrystals in an external field. FIG. 6 shows a polarization spectrum of a DAST microcrystal dispersion system under a magnetic field and an electric field. When only a magnetic field or an electric field is applied, as already reported, an increase in absorbance is observed when only the magnetic field is applied (1) and (2), and when (3) and (4). A decrease in absorbance was observed. When only the electric field of (1) and (3) was applied, an increase in absorbance was observed (FIG. 6ab), and when only the electric field was applied (2) and (4), a decrease in absorbance was observed (FIG. 6cd). .

  In the case of (1), when a magnetic field or an electric field was applied, an increase in absorbance was observed when an electric field or a magnetic field was further applied simultaneously (FIG. 6e). This indicates that the electric field and the magnetic field applied to the microcrystal in the same direction changed the anisotropic orientation state in which both the dipole interaction and diamagnetic interaction of the crystal coincided. In the case of (2), when both a magnetic field and an electric field were applied, the absorbance at the absorption maximum wavelength decreased compared to when no external field was applied, and an increase in absorbance at 500 nm or less and 600 nm or more was observed ( FIG. 6f). This is because the diamagnetic anisotropy and the anisotropy due to the electric dipole interaction are in conflict with each other, and a strong mutual absorption band appears in the wavelength. In the case of (4), when both a magnetic field and an electric field are applied, a large decrease in absorbance is observed because polarized light is incident at the place where the absorption transition moment of anisotropically oriented microcrystals is the smallest (Fig. 6g). When the electric field and magnetic field were applied simultaneously, the crystallites were found to be in an orientation state that received both anisotropic orientation due to dipole interaction due to the electric field and diamagnetic anisotropic orientation due to the magnetic field.

  Next, an example of producing a biaxially oriented DAST microcrystalline dispersion bulk polymer will be described. The DAST microcrystal dispersion was similarly prepared according to Example 1. The orientation fixation of the microcrystalline dispersion was basically performed in the same manner as the method disclosed in Patent Document 3. For photocuring, for example, benzoin isopropyl ether as a photopolymerization initiator is added to the dispersion prepared in Example 1 (for example, 0.1 mol / l), and after replacing with nitrogen gas, a magnetic field (from the direction shown in FIG. The superconducting magnet was used to irradiate an ultrahigh pressure mercury lamp while simultaneously applying an electric field (AC or DC) up to 17 Tesla. FIG. 7 shows, for example, (1), (2), (3), (4), (5) [magnetic field of DAST microcrystalline dispersion bulk polymer prepared by simultaneously applying a magnetic field of 15 Tesla and an electric field of AC 3 kV / cm. And the electric field are both Faraday arrangements and the polarizer is 0 deg.], (6) [90 deg.], (7) [Magnetic field is Faraday arrangement, and the electric field is applied perpendicular to the magnetic field. 0 deg.], (8) [90 deg.] Shows the polarization spectrum in the arrangement.

  Difference in polarization spectrum intensity due to orientation when a magnetic field is applied, approximately 0.4 (Y. kaneko, S. Shimada, T. Fukuda, T. Kimura, H. Yokoi, H. Matsuda, T. Onodera, H. Kasai, S Compared with Okada, H. Oikawa, and H. Nakanishi, Adv. Mater. 2005, 17, 160-163.) (3) and (1) in FIG. ) Difference in absorption intensity, approximately 0.61) was greater. When an electric field is applied from the direction perpendicular to the magnetic field (difference in absorption intensity between (2) and (4) in FIG. 7, approximately 0.65), the dipole interaction and diamagnetic interaction of the crystal It increased further due to the change in the anisotropic orientation state where both coincided. The result is slightly different from that in Example 1. When a magnetic field of 15 Tesla and an electric field of AC 3 kV / cm are applied simultaneously, the strength of the magnetic field is greater than the strength of the electric field, so the orientation is dominant in the diamagnetic interaction. Because it was. That is, the orientation of the microcrystal can be determined in any way by the balance between the strength of the applied magnetic field and the strength of the applied electric field. Thus, by applying a magnetic field and an electric field at the same time, the two axes of the microcrystal could be controlled, and a microcrystalline dispersion polymer that maintained the orientation state could be produced.

  The organic microcrystalline orientation dispersion according to the present invention comprises a dispersion system of organic dyes or organic pigment fine particles useful as dielectrics, magnetic substances, color filters, organic second-order nonlinear optical materials, and various optical / display materials. It can be used as a new organic microcrystal orientation dispersion, and the method for controlling the orientation of organic microcrystals according to the present invention controls the orientation of three orthogonal crystal axes of organic microcrystals necessary for the production of the organic microcrystal orientation dispersion. It can be used as a law.

It is the figure which illustrated the disordered orientation state of the crystal | crystallization in an organic microcrystal dispersion system. It is the figure which illustrated the state where the crystal | crystallization was orientated along one crystal axis by applying a magnetic field or an electric field to an organic microcrystal dispersion system. It is the figure which illustrated typically the concept of the organic microcrystal orientation dispersion | distribution in which the crystal | crystallization was orientated about three crystal axes orthogonal by applying an electric field and a magnetic field simultaneously to an organic microcrystal dispersion system. It is the figure which illustrated the preparation methods of an organic microcrystal dispersion system. It is the schematic diagram which showed the positional relationship of the application direction of an electric field and a magnetic field to an organic microcrystal dispersion system, and an absorption spectrum measurement. FIG. 3 is a graph showing changes in absorbance of the polarization spectrum of the DAST microcrystal dispersion system under application of a magnetic field and an electric field prepared in Example 1. It is the figure which showed the light absorbency change of the polarization spectrum of the DAST microcrystal dispersion bulk polymer under the magnetic field produced in Example 2, and an electric field application.

Claims (18)

1 selected from styrylpyridinium dyes, polydiacetylenes, poly 1,6-di (n-carbazoyl) -2,4-hexadiene: Poly (DCHD), anthracene, tetracene, pentacene, coronene , phthalocyanines, porphyrins By applying a magnetic field and an electric field simultaneously to an organic microcrystal dispersion in which seeds or two or more kinds of microcrystals are dispersed in a dispersion medium, the crystals are anisotropically oriented with respect to three orthogonal crystal axes. A method for controlling the orientation of organic microcrystals. Orientation control method according to claim 1, wherein the organic fine crystals, characterized by applying in a direction intersecting the electric and the magnetic field from each other.   The organic microcrystal orientation control method according to claim 1, wherein an organic solvent having a low dielectric constant is used as the dispersion medium.   The method for controlling the orientation of organic microcrystals according to any one of claims 1 to 3, wherein the solidification is performed after the anisotropic orientation.   The organic microcrystal orientation control method according to any one of claims 1 to 4, wherein a monomer or oligomer of alkylacrylic acid that is crosslinked and cured by light is used as the dispersion medium. Examples of the monomer include octylacrylic acid, laurylacrylic acid, laurylmethacrylic acid linear or branched long-chain alkylacrylic acid, ethyleneglycoxyacrylic acid, and fluorinated alkylacrylic acid having an alkyl group having 7 or more carbon atoms. 6. The method of controlling orientation of organic microcrystals according to claim 5, wherein any one of diacrylic acid, halogen atom, and alkylacrylic acid or alkylmethacrylic acid having various substituents of alkoxy group is used.   6. The method for controlling orientation of organic microcrystals according to claim 5, wherein an alkylacrylic acid monomer and a diacrylic acid monomer derivative are used in combination as the monomer.   The method for controlling the orientation of organic microcrystals according to any one of claims 1 to 7, wherein the dispersion medium is mixed with a dispersion that does not destroy the dispersion state in the dispersion system using a photopolymerization initiator. As before Symbol partial dispersion medium, 2,2, - azo compound azo-bis-isobutyronitrile azobisisobutyronitrile (AIBN), peroxides benzoyl peroxide (BPO), trichloro acetophenone, tris (trichloromethyl) -5- triazine down Helsingborg halogen compounds, acylphosphine oxide compounds of the 2,4,6-trimethylbenzoyl diphenylphosphine oxy de, benzoin alkyl ethers, ketones benzophenone down, one of organometallic compounds of bis penta diethyl titanium di (preventor fluorophenyl) 6. The method for controlling orientation of organic microcrystals according to claim 5, wherein the method is used. 1 selected from styrylpyridinium dyes, polydiacetylenes, poly 1,6-di (n-carbazoyl) -2,4-hexadiene: Poly (DCHD), anthracene, tetracene, pentacene, coronene , phthalocyanines, porphyrins A seed or two or more kinds of microcrystals are anisotropically oriented with respect to three orthogonal crystal axes by simultaneously applying a magnetic field and an electric field, and are dispersed and fixed in a polymer as a dispersion medium Organic microcrystalline alignment dispersion. Organic crystallite orientation dispersion according to claim 10, wherein the to be applied in a direction crossing the electric field and the magnetic field from each other.   The organic microcrystal orientation dispersion according to claim 10 or 11, wherein an organic solvent having a low dielectric constant is used as the dispersion medium.   The organic microcrystal orientation dispersion according to any one of claims 10 to 12, which is solidified after the anisotropic orientation.   The organic microcrystalline alignment dispersion according to any one of claims 10 to 13, wherein an alkylacrylic acid monomer or oligomer that is crosslinked and cured by light is used as the dispersion medium. Examples of the monomer include octylacrylic acid, laurylacrylic acid, laurylmethacrylic acid linear or branched long-chain alkylacrylic acid, ethyleneglycoxyacrylic acid, and fluorinated alkylacrylic acid having an alkyl group having 7 or more carbon atoms. 15. The organic microcrystalline alignment dispersion according to claim 14, wherein any one of diacrylic acid, halogen atom, and alkylacrylic acid or alkylmethacrylic acid having various substituents of alkoxy group is used.   15. The organic microcrystalline alignment dispersion according to claim 14, wherein an alkyl acrylic acid monomer and a diacrylic acid monomer derivative are used in combination as the monomer.   The organic microcrystalline alignment dispersion according to any one of claims 10 to 16, wherein the dispersion medium is mixed with a dispersion that does not destroy the dispersion state in the dispersion system using a photopolymerization initiator. As before Symbol partial dispersion medium, 2,2, - azo compound azo-bis-isobutyronitrile azobisisobutyronitrile (AIBN), peroxides benzoyl peroxide (BPO), trichloro acetophenone, tris (trichloromethyl) -5- triazine down Helsingborg halogen compounds, acylphosphine oxide compounds of the 2,4,6-trimethylbenzoyl diphenylphosphine oxy de, benzoin alkyl ethers, ketones benzophenone down, one of organometallic compounds of bis penta diethyl titanium di (preventor fluorophenyl) 15. The organic microcrystal orientation dispersion according to claim 14, which is used.

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