JP2006241278A - Organic thin film, method for producing the same and optical recording medium using the same organic thin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new organic thin film constructing a dispersed structure of a functional dye of a nano-meter size in an organic polymer, to provide a method for producing the same and to provide an ultrahigh-density optical recording medium carrying out recording and reproduction at a recording density which is impossible to achieve with a conventional optical recording medium and exceeds the diffraction limit of a pick-up lens by applying the organic thin film to the optical recording medium and thereby providingthe optical recording medium in which the area itself of recording layer dots is smaller than the diffraction limit of irradiated light and the recording layer dots are oriented. <P>SOLUTION: The organic thin film has a micro-phase separation structure formed with a block copolymer containing at least one kind of ionic polymer block. The organic thin film comprises the functional dye subjected to ionic bonding to the ionic polymer block forming one phase of the micro-phase separation structure. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention provides an organic compound as a functional composite material that exhibits new functions such as electronic properties, conductive properties, optical properties, etc. by introducing a nanometer-sized functional dye into a polymer and compositing it. The present invention relates to a thin film, a manufacturing method thereof, and an ultrahigh density optical recording medium using the organic thin film.

  It is known that a microphase separation structure of a block copolymer having polymer chains that are incompatible with each other is used as a functional material (Patent Documents 1 to 9 and the like). In addition, introducing a nanometer-sized functional material into a polymer and compositing it makes it possible to create a functional composite material that exhibits new functions such as electronic properties, conductive properties, optical properties, and magnetic properties. This is an important technique for obtaining metal-organic composite materials using ultrafine metal particles (metal nanoclusters) as functional materials (Patent Documents 1 to 6, etc.). Furthermore, examples in which a dye is used as a functional material and applied to an optical recording medium are also known (Patent Documents 8 to 9). However, the research and development of composite materials of nanometer-sized functional organic materials and polymers that can be expected to have unlimited material flexibility and functionality have not been sufficiently advanced. Moreover, although the said patent documents 8-9 are based on the prior application of this applicant, in these invention, the interaction which segregates a pigment | dye only to one phase of phase separation is compatibility of a block polymer and a pigment | dye. The difference is utilized. Therefore, when the difference in compatibility between the block polymer and the dye is not so large, there are many cases in which the state where the dye segregates only in one phase cannot always be formed well. On the other hand, in the present invention, since the interaction is formed by electrostatic ionic bonds, the dye can be surely segregated only in one phase of phase separation.

On the other hand, in the optical memory field, CD-R, DVD-R, and DVD + R that are recordable CD-R, DVD-R, and DVD + R, which are optical recording media having a reflective layer on a substrate, have been commercialized. In such an optical recording medium, further increase in recording capacity and downsizing are desired, and further improvement in recording density is required to realize this.
As elemental technologies for improving the recording capacity in the current system, there are recording pit miniaturization technology and image compression technology represented by MPEG2. As technology for miniaturization of recording pits, it has been studied to increase the numerical aperture NA of the optical system in order to shorten the wavelength of recording / reproducing light and improve the diffraction limit, but recording / reproducing exceeding the diffraction limit is impossible. It is.
Therefore, super-resolution technology capable of recording and reproduction exceeding the diffraction limit and optical memory systems using near-field light have attracted attention as promising means, but they have not yet been put into practical use due to the high technical hurdles. .

In addition, the recording layer of the conventional optical recording medium (layer in which the recording material exists) is usually a continuous layer, and the recording material is irradiated with a laser beam to correspond to the shape of the laser beam on the recording material. Recorded with some change. Therefore, since the size of the minimum recording pit depends on the laser beam diameter determined by the oscillation wavelength and the numerical aperture NA of the lens, in the conventional recording / reproducing system, the increase in density is basically the oscillation wavelength of the laser or the lens. It has been influenced by the practical technology of NA. In addition, since the beam shape is a Gaussian distribution and there is almost no material that changes with a clear threshold for heat or light as a recording material, the size and amount of change of the outermost circumference of the pits to be formed are It is not always uniform, and there is always a variation factor in the reproduction signal quality, and there is a limit in obtaining high quality signal characteristics.

JP-A-10-330492 Japanese Patent Laid-Open No. 10-330528 Japanese Patent Application Laid-Open No. 11-60891 JP 2000-72951 A JP 2000-72952 A Japanese Patent Laid-Open No. 10-330528 JP 2004-306404 A JP 2003-89269 A JP 2003-94825 A

  The present invention provides a novel organic thin film in which a nanometer-sized functional dye dispersion structure, which is expected to be applied as an electronic material and an optical material, is constructed in an organic polymer, and a method for producing the same, and the organic thin film By applying to an optical recording medium, the recording layer dot area itself is smaller than the diffraction limit of the irradiation light, and by making the recording layer dot arrayed, it is impossible to realize with a conventional optical recording medium, An object of the present invention is to provide an ultra-high density optical recording medium capable of recording / reproducing at a recording density exceeding the diffraction limit of a pickup lens.

As a result of intensive studies, the present inventors have made use of the microphase separation phenomenon of a block copolymer containing at least one kind of ionic polymer to form an ionic bond with the ionic polymer that forms one of the phases separated from each other. Incorporating a functional dye into a polymer, a nanometer-sized functional dye is introduced into the polymer to form a composite, and a new functional function such as electronic properties, conductive properties, and optical properties is exhibited. We succeeded in obtaining an organic thin film as a material.
Furthermore, by using the organic thin film as an optical recording medium, the area of the recording body itself is smaller than the diffraction limit of the irradiation light, and the optical recording medium in which the recording body is arranged in a dot array has been successfully obtained. An ultra-high density optical recording medium capable of recording and reproducing at a recording density exceeding the diffraction limit has been obtained.
That is, the said subject is solved by the following 1) -10 invention (henceforth this invention 1-10).
1) Functionality having a microphase separation structure formed by a block copolymer including at least one ionic polymer block, and ion-bonding with an ionic polymer block forming one phase of the microphase separation structure Organic thin film containing pigment.
2) The organic thin film according to 1), wherein the phase separation structure is spherical, columnar, lamellar, co-continuous, or a similar structure thereof.
3) The organic thin film according to 1) or 2), wherein the polymer that forms blocks other than the ionic polymer block is a hydrophobic polymer.
4) The organic thin film according to any one of 1) to 3), wherein the functional dye comprises an ionic dye having a function of changing its optical properties by light or heat.
5) After preparing a solution containing a block copolymer containing an ionic polymer block and an ionic dye, one phase of the phase separation structure is formed by forming a thin film by a solution coating method to form a phase separation structure. The manufacturing method of the organic thin film in any one of 1) -4) containing the functional pigment | dye ion-bonded with the ionic polymer block to form.
6) A solution containing a block copolymer containing an ionic polymer block is prepared, a thin film is formed by a solution coating method to form a phase separation structure, and then contacted with a solution containing an ionic dye. The manufacturing method of the organic thin film in any one of 1) -4) containing the functional dye ion-bonded with the ionic polymer block which forms one phase of a structure.
7) A solution containing a block copolymer containing an ionic polymer block is prepared, a thin film is formed by a solution coating method to form a phase separation structure, an ionic dye is laminated thereon, and then heat diffusion is performed. The method for producing an organic thin film according to any one of 1) to 4), which contains a functional dye ionically bonded to an ionic polymer block that forms one phase of a phase separation structure.
8) An optical recording medium wherein the recording layer comprises the organic thin film according to any one of 1) to 4).
9) The optical recording medium according to 8), which contains a functional dye whose wavelength is controlled to have a maximum absorption wavelength near the wavelength of the recording / reproducing laser.
10) The optical recording medium according to 8), which contains a functional dye whose wavelength is controlled to have a maximum refractive index in the vicinity of the wavelength of the recording / reproducing laser.

Hereinafter, the present invention will be described in detail.
The organic thin film of the present invention is a block copolymer containing at least one ionic polymer, and contains a functional dye ionically bonded to the ionic polymer forming one phase of the phase separation structure. Is. A feature of this organic thin film is that the functional dye is nanometer-sized and highly ordered in the polymer matrix. The micro phase separation phenomenon of the block copolymer is used as the driving force. The microphase-separated structure is preferably a co-continuous shape such as a spherical shape, a columnar shape, or a lamellar shape, or a similar structure thereof, and the functional dye is preferably a dye having a function of changing its optical properties by light or heat.
1A to 1C show examples in which a functional pigment is contained in a spherical, columnar, or lamellar structure.
As described above, by introducing a nanometer-sized functional dye into a polymer and complexing it with three-dimensional highly structural control, new electronic properties, conductive properties, optical properties, etc. An organic thin film that exhibits its function can be obtained.

Next, the manufacturing method of the said organic thin film is demonstrated.
It has been known before this application that a block copolymer composed of two or more types of polymer blocks that are incompatible with each other forms a microphase separation structure by solvent casting or temperature change. It is manufactured by the following method utilizing a known phenomenon.
That is, the first method is a method of preparing a phase separation structure by preparing a solution containing a block copolymer containing an ionic polymer and an ionic dye and then forming a thin film by a solution coating method.
In the second method, a solution containing a block copolymer containing an ionic polymer is prepared, a thin film is formed by a solution coating method, and then a heat treatment is performed to form a phase separation structure. It is the method of making it contact with the solution to contain.
In the third method, a solution containing a block copolymer containing an ionic polymer is prepared, a thin film is formed by a solution coating method, and then a heat treatment is performed to form a phase separation structure, on which an ionic property is formed. This is a method of heating and diffusing after laminating the dye.
In any of the above methods, the formation of the phase separation structure may be promoted by heating at a temperature equal to or higher than the glass transition point of the block copolymer. In order to make such a phase separation structure easier to express, it is more preferable that the block polymer other than the block containing the ionic polymer is a block copolymer which is a hydrophobic polymer, and further promotes phase separation. Therefore, other polymers may be added in addition to the block copolymer.

Next, an optical recording medium using the organic thin film as a recording layer material will be described.
In the optical recording medium using the organic thin film of the present invention, recording layer dots that are highly ordered exist in a continuous layer in a discontinuous manner through a matrix, and the size of the recording layer dots is uniform. Nanometer size (10-500 nm) is formed. Therefore, the size of the minimum recording pit is not determined by the laser oscillation wavelength or the lens NA, but is determined only by the recording layer dots to be formed, and an optical recording medium having an arbitrary recording density can be designed.
Further, in the conventional optical recording medium, since the recording layer is formed of a uniform film, when irradiated with a laser, the light absorption distribution on the recording layer is further changed according to the light intensity distribution, and further, the heat distribution is converted into heat. Is formed. And reaction occurs in the part more than the threshold value of photon mode and heat mode reaction, and a pit is formed. However, in a normal reaction, the threshold value is not so clear, and the boundary of formed pits varies, that is, the pit shape varies, causing a data error. On the other hand, in the structure of the present invention, the portion that absorbs light is isolated (one layer of the phase separation structure), and the size of the phase separation structure is a pit shape. Does not fluctuate. That is, since the outermost peripheral edge of the pit is also determined by the structure of the organic thin film, it is possible to obtain high-quality signal characteristics free from pit variations by recording this entire recording layer dot. It becomes possible.

Next, the layer configuration of the optical recording medium and the necessary physical properties of each layer will be described.
<Layer structure of recording medium>
The layer structure of the optical recording medium of the present invention may be a write-once optical disk structure (a so-called air sandwich structure in which two recording layers are provided on a substrate) and a CD-R structure (on a substrate). A structure having a recording layer, a reflective layer, and a protective layer) or a DVD structure in which a CD-R structure is bonded. An example of a typical layer structure is shown in FIGS. In the figure, 1 is a substrate, 2 is a recording layer, and 3 is a reflective layer.
"substrate"
The substrate must be transparent to the laser used when recording / reproduction is performed from the substrate side, but is transparent to the laser used when recording / reproduction is performed from the recording layer side (the side opposite to the substrate). There is no need.
As the substrate material, for example, plastics such as polyester resin, acrylic resin, polyamide resin, polycarbonate resin, polyolefin resin, phenol resin, epoxy resin, polyimide resin, glass, ceramic, metal, and the like can be used. Note that a guide groove for tracking, a guide pit, and a preformat such as an address signal may be formed on the surface of the substrate.

<Recording layer>
The recording layer is capable of causing some optical change upon irradiation with laser light, and recording and reproducing information by the change, and is a microphase separation formed by a block copolymer including at least one ionic polymer block. It consists of an organic thin film containing a functional dye (optical recording dye) ionically bonded to an ionic polymer block that has a structure and forms one phase of the microphase separation structure.
There are various optical characteristics that functional dyes (optical recording dyes) should retain, but when reproducing using the change in absorption characteristics (change in transmittance) with respect to the recording / reproducing laser wavelength, the vicinity of the laser wavelength It is preferable to control the wavelength so that it has the maximum absorption wavelength. When reproducing using the change in refractive index of the recording / reproducing laser wavelength, the wavelength is controlled so that the maximum refractive index is in the vicinity of the laser wavelength. It is preferable to do. In addition, in the case of a method in which the fluorescence characteristics of the dye are changed by laser light irradiation and reproduction is performed using the change, the S / N ratio is larger than in the case of using the change in transmittance or the change in refractive index. Even if a slight change is possible, reproduction with high contrast is possible, and when the size of the recording pit as in the optical recording medium of the present invention is determined from the beginning, the energy is very low compared to the conventional method. This is particularly preferable because recording is possible. In the conventional method, a clear pit shape must be formed by recording, and recording cannot be performed unless the reaction rate of the recording layer material by laser light irradiation is high. On the other hand, in the optical recording medium of the present invention in which pits are already formed, reproduction is possible even with a small reaction rate, and fluorescence reproduction is particularly effective.

The block copolymer used in the present invention is synthesized by combining monomers that form two or more types of polymer blocks including at least one type of ionic polymer block. Examples of the synthesis method include a living polymerization method in which polymerization is performed from the end of the monomer, a living polymerization method in which synthesis is performed from the center of the polymer chain, and a synthesis method in which the ends of the terminal functional polymer are bonded. In order to promote the phase separation structure, it is preferable that the polymers forming the blocks are incompatible with each other, and the polymer forming the blocks other than the ionic polymer block is more preferably a hydrophobic polymer.
The ionic polymer refers to a polymer in which an ionic functional group is covalently bonded as a side chain to a polymer serving as a main chain, and the polymer serving as a main chain is not particularly limited. When the ionic functional group is an anionic functional group, the resulting polymer is called an anionic polymer, and when the ionic functional group is a cationic functional group, it is called a cationic polymer.

Examples of the ionic functional group include an anionic functional group and a cationic functional group.
Examples of the anionic functional group include —CO ₂ ^— (carboxylic acid group), —SO ₃ ^— (sulfonic acid group), —OSO ₃ ²⁻ (sulfuric acid group), —PO ₄ ³⁻ (phosphoric acid group), -B _{(OH) 2} ^- and the like (boronic acid). Such an anionic functional group may be bonded to a metal cation or an organic cation. Examples of the metal cation include alkali metals such as Na ⁺ (sodium cation), K ⁺ (potassium cation), and Ca ⁺ (calcium cation). Examples of the organic cation include Me ₃ N ⁺ H (trimethylammonium cation), Et ₃ N ⁺ H (triethylammonium cation), Me ₂ N ⁺ H ₂ (dimethylammonium cation), and the like.
Examples of the cationic functional group include guanidinium ion, —NH ₃ ⁺ , —NH ₂ (CH ₃ ) ⁺ , —NH (CH ₃ ) ²⁺ , —N (CH ₃ ) ³⁺ , and the following [Chemical ^Formula 1]: And the group represented. Such a cationic functional group may be combined with a halogen anion such as chlorine or bromine, a sulfate anion, a sulfonate anion, a phosphate anion, a carboxylate anion or the like to form a salt.

上記した中で、アニオン性官能基としては、−ＣＯ_２ ⁻、−ＳＯ_３ ⁻が好ましく、カチオン性官能基としては、−ＮＨ_３ ^＋、−Ｎ（ＣＨ_３）_３ ^＋、上記〔化１〕の基が好ましい。更に好ましいのは、−Ｎ（ＣＨ_３）_３ ^＋、及び上記〔化１〕を含む基である。
このようなイオン性官能基は、主鎖となるポリマーに直接結合していても、他の結合基、例えば、炭素原子数１〜６のアルキレン基、フェニレン基、エチレンオキシ基〔（Ｃ_２Ｈ_４Ｏ）ｎ〕などを介してポリマーの主鎖に結合していてもよい

Among the above, the anionic functional group is preferably —CO ₂ ^— or —SO ₃ ^— , and the cationic functional group is —NH ₃ ⁺ , —N (CH ₃ ) ₃ ⁺ , or the above [Chemical Formula 1]. Are preferred. Further preferred is a group containing —N (CH ₃ ) ₃ ⁺ and the above [Chemical Formula 1].
Even if such an ionic functional group is directly bonded to the polymer as the main chain, other bonding groups such as an alkylene group having 1 to 6 carbon atoms, a phenylene group, an ethyleneoxy group [(C ₂ H ₄ O) n] or the like may be bonded to the main chain of the polymer.

An ionic dye is used as the recording dye. An ionic dye refers to a dye having an ionic functional group covalently bonded thereto. As the ionic functional group, those similar to the above are used.
For example, ionic, polymethine-based, squarylium-based, pyrylium-based, porphyrin-based, porphyrazine-based, azo-based, azomethine-based dyes that change their optical constants in the heat mode (thermal decomposition, etc.) by the irradiation energy of laser light, And their metal complex compounds, fulgides whose optical constants are changed in photon mode by the irradiation energy of laser light, diarylethenes, azobenzenes, spiropyrans, stilbenes, dihydropyrenes, thioindigos, bipyridines, aziridines, Photochromic materials such as aromatic polycycles, allylidene anilines, and xanthenes can be mentioned, and photochromic materials capable of rewriting recording are particularly preferable. The above dyes may be used alone or in combination of two or more.
Furthermore, a stabilizer (for example, a transition metal complex), an ultraviolet absorber, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer, etc. may be added to the recording layer for the purpose of improving characteristics. it can. The dot diameter of the functional dye (optical recording dye) is 5 to 500 nm, preferably 10 to 200 nm.

<Underlayer>
The undercoat layer is a) improved adhesion, b) a barrier such as water or gas, c) improved storage stability of the recording layer, d) improved reflectance, e) protection of the substrate from the solvent, f) Used for the purpose of forming guide grooves, guide pits, preformats, etc. For the purpose of a), various polymer compounds such as ionomer resins, polyamide resins, vinyl resins, natural resins, natural polymers, silicones, liquid rubbers, and polymer materials such as silane coupling agents are used. it can, b) for the purposes of the to c), in addition to the polymeric _{materials, SiO, MgF, SiO 2,} TiO, ZnO, TiN, an inorganic compound such as SiN, Zn, Cu, Ni, Cr, A metal or a semimetal such as Ge, Se, Au, Ag, or Al can be used. For the purpose of d), metals such as Al, Au and Ag, and organic thin films having metallic luster such as methine dyes and xanthene dyes can be used, and for the purposes of e) to f). For example, an ultraviolet curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used.
The thickness of the undercoat layer is 0.01 to 30 μm, preferably 0.05 to 10 μm.

《Metal reflective layer》
The metal reflective layer is used when necessary according to the required reflectance.
Examples of the material for the metal reflective layer include metals and semi-metals that are not easily corroded and have high reflectivity, and specific examples include Au, Ag, Cr, Ni, Al, Fe, and Sn. Au, Ag, and Al are most preferable from the viewpoint of reflectance and productivity. These metals and metalloids may be used alone or as two kinds of alloys.
Examples of the method for forming the reflective film include vapor deposition and sputtering, and the film thickness is 50 to 5000 mm, preferably 100 to 3000 mm.

《Protective layer, hard coat layer on substrate surface》
The protective layer and the substrate hard coat layer are: a) protection of the recording layer (reflection / absorption layer) from scratches, dust, dirt, etc., b) improvement of storage stability of the recording layer (reflection / absorption layer), and c) reflectance. It is used for the purpose of improvement. For these purposes, the materials shown for the undercoat layer can be used. In addition, SiO, SiO ₂ or the like can be used as the inorganic material, and polymethyl acrylate, polycarbonate, epoxy resin, polystyrene, polyester, vinyl resin, cellulose, aliphatic hydrocarbon resin, natural rubber, styrene butadiene resin as the organic material. Also, heat softening and heat melting resins such as chloroprene rubber, wax, alkyd resin, drying oil and rosin can be used. The most preferable among the above materials is an ultraviolet curable resin excellent in productivity.
The film thickness of the protective layer or the substrate surface hard coat layer is 0.01 to 30 μm, preferably 0.05 to 10 μm.
The undercoat layer, protective layer, and substrate side hard coat layer are provided with a stabilizer, a dispersant, a flame retardant, a lubricant, an antistatic agent, a surfactant, a plasticizer, etc., as in the case of the recording layer. It can be included.

  ADVANTAGE OF THE INVENTION According to this invention, the novel organic thin film which constructed | assembled the functional pigment | dye dispersion | distribution structure of a nanometer size expected in an electronic material and an optical material in the organic polymer, and its manufacturing method can be provided. Further, by applying the organic thin film to an optical recording medium, the recording layer dot area itself is smaller than the diffraction limit of irradiation light, and the recording layer dot is arranged into an optical recording medium. Thus, it is possible to provide an ultra-high density optical recording medium that can be recorded and reproduced at a recording density exceeding the diffraction limit of the pickup lens, which is impossible to realize.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited by these Examples.

<< Examples 1 and 2 >>
It consists of poly (p-tertiarybutyl) styrene having a number average molecular weight of about 95,000 and sodium polystyrene sulfonate, and the volume fraction of sodium polystyrene sulfonate is 21% by volume (Example 1) and 32% by volume (Example). 2) was synthesized by a living polymerization method.
These copolymers were dissolved in pyridine to form a cast film on mica.
By SAXS measurement and TEM observation, it was confirmed that the phase separation structure of the cast film was a spherical structure and a columnar structure of several tens of nm or less, respectively.
Next, these cast films were immersed in a 0.5 wt% methanol / butanol (5/1 weight ratio) solution of the dye of the following [Chemical Formula 2]. By TEM observation of the surface layer of these cast films, it was confirmed that the dye was present in a spherical structure or a columnar structure made of polystyrenesulfonic acid.

Example 3
A block copolymer consisting of polyhydroxyethyl methacrylate having a number average molecular weight of about 65,000 and sodium polystyrene sulfonate and having a volume fraction of 49% by volume of sodium polystyrene sulfonate was synthesized by a living polymerization method.
Using this copolymer, a cast film was formed on mica in the same manner as in Example 1, and then annealed at 110 ° C. for 12 hours.
It was confirmed by SAXS measurement and TEM observation that the phase separation structure of the cast membrane was a lamellar columnar structure.
On this cast film, a 0.5 wt% methanol / butanol (9/1 weight ratio) solution of the dye of the following [Chemical Formula 3] was spin-coated to laminate a dye film.
Then, after heating at 110 degreeC for 5 hours, ethanol washing | cleaning was carried out and the surface dye layer was removed. By TEM observation of the surface layer of this cast film, it was confirmed that the dye was present in the lamellar structure made of polystyrene sulfonic acid.

Example 4
A block copolymer composed of poly (p-tertiarybutyl) styrene having a number average molecular weight of about 95,000 and sodium polyacrylate and having a volume fraction of sodium polyacrylate of 31% by volume is synthesized by a living polymerization method. did.
This block copolymer and the dye of [Chemical Formula 2] were dissolved in pyridine at a weight ratio of 200/1 to form a cast film on quartz, and then annealed at 110 ° C. for 12 hours.
By SAXS measurement and TEM observation, it was confirmed that the phase separation structure of the cast film was a columnar structure of several tens of nm or less, and the dye was present in the columnar structure made of polyacrylic acid.

Example 5
A block copolymer comprising poly (p-tertiarybutyl) styrene having a number average molecular weight of about 95,000 and polymethacryloxyethyltrimethylammonium chloride, wherein the volume fraction of polymethacryloxyethyltrimethylammonium chloride is 32% by volume. Was synthesized by a living polymerization method.
The block copolymer and the dye of the following [Chemical Formula 4] were dissolved in pyridine at a 200/1 weight ratio to form a cast film on quartz.
By SAXS measurement and TEM observation, it was confirmed that the phase separation structure of the cast membrane was a columnar structure of several tens of nm or less, and the dye was present in a columnar structure composed of polymethacryloxyethyltrimethylammonium.

Example 6
A cast film was prepared in the same manner as in Example 5 except that instead of polymethacryloxyethyltrimethylammonium chloride, a copolymer of polymethacryloxyethyltrimethylammonium chloride and n-butyl acrylate (volume fraction 56/44) was used. Formed.
According to the SAXS measurement and TEM observation, the phase separation structure of the cast film is a columnar structure of several tens of nm or less, and the dye is present in the columnar structure composed of a copolymer of polymethacryloxyethyltrimethylammonium and n-butylacrylate. I was able to confirm.

  From the above results, it was revealed that the organic thin films prepared in Examples 1 to 6 were organic thin films in which nanometer-sized spherical, columnar, and lamellar functional dye dispersion structures were constructed in an organic polymer. . Due to the function of the functional dye and the highly ordered structure, new electronic properties, conductive properties, and optical properties are expected to be expressed.

Example 7
An organic thin film (film thickness: about 80 nm) was formed in the same manner as in Example 1 except that the substrate was changed from mica to a PMMA substrate surface-cured with an acrylic photopolymer, and the organic thin film was used as a recording layer. An optical recording medium was obtained. The phase separation structure was the same as in Example 1.

Example 8
An organic thin film (film thickness: about 60 nm) was formed in the same manner as in Example 3 except that the substrate was changed from mica to a PMMA substrate surface-cured with an acrylic photopolymer, and the organic thin film was used as a recording layer. An optical recording medium was obtained. The phase separation structure was the same as in Example 3.

Example 9
An organic thin film (film thickness: about 70 nm) was formed in the same manner as in Example 4 except that the substrate was changed from mica to a PMMA substrate surface-cured with an acrylic photopolymer, and the organic thin film was used as a recording layer. An optical recording medium was obtained. The phase separation structure was the same as in Example 4.

Example 10
An organic thin film (film thickness: about 70 nm) was formed in the same manner as in Example 5 except that the substrate was changed from mica to a PMMA substrate surface-cured with an acrylic photopolymer, and the organic thin film was used as a recording layer. An optical recording medium was obtained. The phase separation structure was the same as in Example 4.

<< Comparative Example 1 >>
Except for the point that only a block copolymer cast film composed of poly (p-tertiarybutyl) styrene and sodium polystyrenesulfonate has a volume fraction of 21 vol% is used as the recording layer. An optical recording medium was obtained in the same manner as in Example 7.

<< Comparative Example 2 >>
Only a block copolymer cast film comprising poly (p-tertiarybutyl) styrene and polymethacryloxyethyltrimethylammonium chloride and having a volume fraction of polymethacryloxyethyltrimethylammonium chloride of 32% by volume is used as a recording layer. Except for the points described above, an optical recording medium was obtained in the same manner as in Example 10.

上記の結果から、ナノメータサイズの球状、柱状、ラメラ状の機能性色素分散構造を有機ポリマー中に構築された有機薄膜に記録が可能なことが明らかである。
本実験では、ナノメータサイズの色素分散構造に比較し大きなビーム径（１．６μｍ）の光源を用いたため、多数の色素分散構造を一度に記録したが、色素分散構造と同程度のビーム径で記録すれば、色素分散構造に対し個別に記録することが可能である。
このように本発明の有機薄膜を光記録媒体に応用することにより、従来の光記録媒体では実現不可能なピックアップレンズの回折限界を越えた記録密度での記録再生が可能となることが確認された。 On these optical recording media, a semiconductor laser having an oscillation wave of 780 nm and a beam diameter of 1.6 μm was scanned 1.0 cm ^{2 at} intervals of 2.0 μm in the horizontal direction. The irradiated part and the unirradiated part were observed with a TEM, an optical microscope, and the transmittance was measured with a spectroscope. The results are shown in Table 1.

From the above results, it is clear that nanometer-sized spherical, columnar, and lamellar functional dye dispersion structures can be recorded on an organic thin film constructed in an organic polymer.
In this experiment, since a light source with a larger beam diameter (1.6 μm) was used compared to a nanometer-size dye dispersion structure, a large number of dye dispersion structures were recorded at one time, but with a beam diameter comparable to the dye dispersion structure. Then, it is possible to record individually on the dye dispersion structure.
Thus, it was confirmed that recording and reproduction at a recording density exceeding the diffraction limit of the pickup lens, which cannot be realized with a conventional optical recording medium, can be achieved by applying the organic thin film of the present invention to an optical recording medium. It was.

The schematic diagram which shows the typical micro phase-separation structure of the organic thin film of this invention. (A) Spherical structure (sea-island structure), (b) columnar structure, (c) alternating lamellar structure. 1 is a diagram showing a typical layer configuration of an optical recording medium of the present invention. (A) Configuration having a recording layer on a substrate, (b) Configuration having a reflective layer, and (c) Configuration having a reflective layer and a recording layer in this order on the substrate.

Explanation of symbols

1 Substrate 2 Recording layer 3 Reflective layer

Claims (10)

  A functional dye having a microphase separation structure formed of a block copolymer containing at least one ionic polymer block, and ionically bonded to the ionic polymer block forming one phase of the microphase separation structure Contains organic thin film.   The organic thin film according to claim 1, wherein the phase separation structure is spherical, columnar, lamellar, co-continuous, or a similar structure thereof.   The organic thin film according to claim 1 or 2, wherein the polymer forming the block other than the ionic polymer block is a hydrophobic polymer.   The organic thin film according to any one of claims 1 to 3, wherein the functional dye comprises an ionic dye having a function of changing its optical properties by light or heat.   After preparing a solution containing a block copolymer containing an ionic polymer block and an ionic dye, a thin film is formed by a solution coating method to form a phase separation structure, and one phase of the phase separation structure is formed The manufacturing method of the organic thin film in any one of Claims 1-4 containing the functional pigment | dye ion-bonded with the ionic polymer block.   A solution containing a block copolymer containing an ionic polymer block is prepared, a thin film is formed by a solution coating method to form a phase separation structure, and then contacted with a solution containing an ionic dye. The manufacturing method of the organic thin film in any one of Claims 1-4 containing the functional pigment | dye ion-bonded with the ionic polymer block which forms one phase.   A solution containing a block copolymer containing an ionic polymer block is prepared, a thin film is formed by a solution coating method to form a phase separation structure, an ionic dye is laminated thereon, and then heated and diffused. The manufacturing method of the organic thin film in any one of Claims 1-4 containing the functional dye ion-bonded with the ionic polymer block which forms one phase of a isolation | separation structure.   An optical recording medium, wherein the recording layer comprises the organic thin film according to claim 1.   9. The optical recording medium according to claim 8, comprising a functional dye whose wavelength is controlled to have a maximum absorption wavelength in the vicinity of the wavelength of the recording / reproducing laser. 9. The optical recording medium according to claim 8, comprising a functional dye whose wavelength is controlled to have a maximum refractive index in the vicinity of the wavelength of the recording / reproducing laser.

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