JP2006299106A - Block copolymer membrane having cylinder structure orienting perpendicularly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for simply producing a block copolymer membrane having a cylinder structure orienting in the perpendicular direction to the membrane surface and having a small turbulence of an orienting angle. <P>SOLUTION: This invention relates to the block copolymer membrane which has the membrane thickness of 0.1 μm-50 mm and the cylinder structure which orients in the perpendicular direction to the membrane surface and has an absolute value of less than 9° of the turbulence of the orienting angle to the vertical orienting prescribed by the half width at half maximum by two-dimensional small angle X-ray scattering measuring, and to its production method. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a block copolymer film having a cylinder structure oriented in a direction perpendicular to the film surface and a method for producing the same.

Technology that imparts a fine structure to materials and uses their unique functions and physical properties is generally called nanotechnology. In recent years, it is expected to be applied not only in the electronics field but also in a wide range of fields such as energy and environment. .
As materials that can form nanometer-order patterns on a substrate in a self-organized manner and can be applied to the manufacture of magnetic recording media, solar cells, light-emitting elements, precision filters, etc., aromatic ring-containing polymer chains and acrylic polymer chains A pattern material that contains a block copolymer or graft copolymer having a structure and forms a microphase-separated structure is known (Patent Documents 1 and 2). However, a film having a cylinder structure oriented in a direction perpendicular to the film surface has not been studied. For example, in Patent Document 1, a spherical microphase separation structure is formed in a hexagonal fine film in a thin film having a thickness of about the diameter of a sphere. It merely discloses the applied technology of the phenomenon of filling (self-organizing ability).
JP 2001-151834 A JP 2002-279616 A

On the other hand, Non-Patent Documents 1 and 2 disclose a method of orienting a lamella or cylinder in a diblock copolymer or a triblock copolymer in parallel with the film surface using a flow field.
"Spherulite formation from microphase-separated lamellae in semi-crystalline diblock copolymer comprising polyethylene and atactic polypropylene blocks"; M. Ueda, K. Sakurai, S. Okamoto, DJ Lohse, WJ MacKnight, S. Shinkai, S. Sakurai, S. Nomura (2003, Polymer, 44, pp. 6995-7005) "Synchrotron Small-Angle X-ray Scattering Studies on Flow-Induced Gyroid to Cylinder Transition in an Elastomeric SBS Triblock Copolymer"; S. Sakurai, T. Kota, D. Isobe, S. Okamoto, K. Sakurai, T. Ono, K. Imaizumi, S. Nomura (2004, J. Macromol. Sci., Physics, B43, pp. 1-11)

Also known is a method of producing a block copolymer film having a vertically aligned lamella structure by placing a block copolymer resin on a substrate having a predetermined characteristic surface roughness or more and heat-treating the resin. (Patent Document 3).
JP 2004-99667 A

However, the method described in Patent Document 3 is a method of orienting the lamella structure perpendicularly to the film surface, and has a disadvantage that the arrangement of the lamella structure in the obtained film surface cannot be defined. In addition, as in the case of a cylinder structure, there is a disadvantage that it is hardly possible to apply nanopores (micropores) by post-processing.
Therefore, studies for providing a vertically aligned cylinder structure have also been conducted as follows.

For example, when a polystyrene-polymethyl methacrylate diblock copolymer film is cast on an electrode plate and a DC voltage of 30 to 40 V / μm is applied at 165 ° C. for 14 hours, a cylinder made of polymethyl methacrylate is vertically aligned. It has been reported (Non-Patent Document 3). However, since the obtained diblock copolymer film has a very thin film thickness of 1 μm or less, its utility value as a material was small. Further, according to this method, a complicated process of applying an electric field is required, and this method cannot be applied to a polymer that does not respond to an electric field.
Ultrahigh-Density Nanowire Arrays Grown in Self-Assembled Diblock Copolymer Templates, T. Thurn-Albrecht, J. Schotter, GA Kaestle, N. Emley, T. Shibauchi, L. Krusin-Elbaum, K. Guarini, CT Black, MT Tuominen , and TP Russell, Science Dec 15 2000: 2126-2129

In addition, a method of forming a cylinder structure standing perpendicular to the surface by casting a polystyrene-polymethyl methacrylate diblock copolymer after grafting a random copolymer of styrene-methyl methacrylate is also known ( Non-patent document 4). However, this method is not only complicated, but the diblock copolymer film obtained has an extremely thin film thickness of 30 nm or less, and thus has a low utility value as a material. In addition, although the cylinders were vertically oriented, the arrangement (arrangement of the cross section of the cylinder) when viewed in the film plane was random.
K. Shin, KA Leach, JT Goldbach, DH Kim, JY Jho, M. Tuominen, CJ Hawker, TP Russell, Nano Letters, 2, 933 (2002)

In addition, it has been proposed to prepare a vertically aligned mesoporous silica film by using a novel polysilicate as an intermediate (Patent Document 4). However, in the case of such a material, it is difficult to dissolve it in an organic solvent or to thermally decompose it, so that it is not suitable for use as a template such as a nano template.
JP 2003-335516 A

In addition, in order to obtain a microphase-separated structure film having a uniform alignment direction, the molecular weight distribution (Mw / Mn) of each polymer component in the block copolymer comprising the hydrophilic polymer component (A) and the hydrophobic polymer component (B) There has been proposed a method for adjusting (Patent Document 5).
However, in this method, even when viewed from the electron micrograph attached to this document, the film thickness is at most several μm and extremely thin, so that only a film that satisfies the practically required mechanical strength can be obtained. There was an inconvenience that was not possible.
JP 2004-124088 A

The present inventors use a predetermined styrene-ethylenebutylene-styrene triblock copolymer to form a spherical microphase separation structure by a solution casting method using a selective solvent, and heat-treat this at a temperature of 150 ° C. for 10 hours. The method to do was proposed (nonpatent literature 5). This document discloses that the heat treatment has changed the shape from a spherical to a cylindrical microphase separation structure.
"Effect of Microphase Separation Structure on Mechanical Properties of Styrene-Ethylene Butylene-Styrene Triblock Copolymer Films"; Hideo Hamada, Sakae Aida, Shinichi Sakurai, Yuichi Kitagawa, Yoshikazu Suda, Junzo Masamoto, Haruji Nomura (1997) , Journal of the Japanese Society of Rheology, Vol. 25, pp. 217-220)

However, in the same document, it has not been confirmed in which direction the cylinder is present with respect to the film surface when the spheres coalesce to form the cylinder. Therefore, when the present inventors re-examined the method described in the document, it was found that although the vertical alignment was confirmed, the disorder of the alignment angle was ± 9 °. When high functionality is expressed by utilizing the vertical orientation, it is often insufficient when the orientation angle is largely disturbed.
Therefore, the present inventors have made extensive studies to overcome the above technical problems and produce a vertically aligned cylinder material with a small orientation angle disturbance, and as a result, obtain a vertical alignment with a small orientation angle disturbance. Succeeded.

  The present invention solves the disadvantages in the prior art, and a block copolymer film having a cylinder structure vertically aligned with a disturbance of less than ± 9 ° with respect to the film surface, and a method for easily producing the block copolymer film It is an issue to provide.

The present invention has a film thickness of 0.1 μm to 50 mm, is oriented in the direction perpendicular to the film surface, and is disordered in the orientation angle with respect to the vertical orientation defined by the half width at half maximum by two-dimensional small-angle X-ray scattering measurement. Relates to a block copolymer film having a cylinder structure with an absolute value of less than 9 °.
Furthermore, the present invention relates to a direction perpendicular to the membrane surface comprising merging a spherical structure in a microphase-separated structure formed from a block copolymer into a cylinder structure by merging in a direction perpendicular to the membrane surface. The present invention relates to a method for producing a block copolymer film having a cylindrical structure oriented in the direction.

According to the present invention, a block copolymer film having a cylinder structure oriented in a direction perpendicular to the film surface can be easily produced.
Further, according to the present invention, the vertical alignment of the cylinder, which has not been realized so far, can be realized by a simple and low-cost method. That is, the method of the present invention can be said to be an extremely simple and low-cost method without requiring a complicated operation such as application of an electric field, application of a temperature gradient, or zone heating in order to achieve vertical alignment of the cylinder.
Therefore, according to the present invention, it is possible to design highly functional materials in a wide range of fields. Examples of highly functional materials include nanowires, nanostamps, nanoporous materials, nanoporous hollow fibers, nanoporous tubes, and the like. Such high-functional materials include, for example, high-performance optical materials such as electronic information recording media and optical retardation films, adsorbents, nano-reaction field membranes, catalysts, high-function membranes (nano-reaction fields, catalysts, separation membranes), high-performance materials. It can be used for applications such as functional hollow fibers, high performance tubes, nano templates, and nano molds.

  The block copolymer constituting the block copolymer film of the present invention is not limited at all without departing from the object of the present invention, and any conventionally known block copolymer can be used. As the block structure of the block copolymer, AB type, A (BA) n type (where n represents a natural number, preferably n = 1 to 3), A (BAB) m, (m is A linear block copolymer represented by a natural number, preferably m = 1 to 2, and (AB) pX (where p represents a natural number, preferably p = 3 to 5. X is And a star block copolymer having a B moiety as a bond center, represented by a multifunctional functional group (atomic group) that causes branching. Among these, in order to form a clear cylinder without branching or bending, an AB type or ABA type block copolymer is preferable, and an ABA type triblock copolymer is particularly preferable. Moreover, you may blend and use 2 or more types of said block copolymer.

  Further, the block copolymer film of the present invention is formed by further blending the above one or more block copolymers with a homopolymer comprising components constituting each block (for example, component A and / or component B). You can also

The block copolymer in the present invention is composed of two or more types, more preferably two types of repeating monomer units, and the block chain (polymer component) formed from at least one type of repeating monomer units A is at a normal casting temperature. A glassy state at 23 ° C. is preferable because it is easy to freeze (fix) the non-equilibrium morphology by vitrification. In one embodiment of the present invention, the polymer component formed from at least one other repeating monomer unit B is preferably in a rubbery state at 23 ° C.
The volume fraction of the polymer component (glass component) formed from the above repeating monomer unit A and the polymer component (for example, rubber component) formed from the above repeating monomer unit B is any of 0.1 to 0.4. It is effective and preferable for forming a cylinder structure, and a component having a small volume fraction can form a cylinder structure, and a component having a large volume fraction can form a matrix phase. The volume fraction is more preferably 0.11 to 0.35, further preferably 0.12 to 0.3, and particularly preferably 0.13 to 0.25. It is more preferable that the volume fraction of the polymer component (glass component) formed from the repeating monomer unit A with respect to the block copolymer is 0.1 to 0.4 because it is easy to form a cylinder structure. 0.35 is more preferable, 0.12 to 0.3 is still more preferable, 0.13 to 0.25 is particularly preferable, and 0.15 to 0.24 is most preferable.

  As to whether the block chain (polymer component) formed from repeating monomer units is in a glass state or a rubber state, and the glass transition temperature of the polymer component, a general method for measuring the glass transition temperature, for example, differential scanning. It can be confirmed by calorimetric analysis (DSC) or dynamic viscoelasticity measurement.

  In the present invention, it is important that the block chain has a composition capable of forming a cylinder structure in a thermodynamic equilibrium or quasi-equilibrium state. It is also important that the block chain has a composition that allows a spherical structure to be easily formed by using a selective solvent described later. From such a viewpoint, the volume fraction of the polymer component (glass component) formed from the repeating monomer unit A with respect to the block copolymer is preferably 0.1 to 0.4, and preferably 0.11 to 0.35. More preferably, 0.12 to 0.3 is more preferable, 0.13 to 0.25 is particularly preferable, and 0.15 to 0.24 is most preferable. When the AB type or ABA type block copolymer is used, the volume fraction of the polymer component (for example, rubber component) formed from the repeating monomer unit B with respect to the block copolymer may be 0.9 to 0.6. Preferably, 0.89 to 0.65 is more preferable, 0.88 to 0.7 is further preferable, 0.87 to 0.75 is particularly preferable, and 0.85 to 0.76 is most preferable. preferable. The polymer component formed from the repeating monomer unit A preferably constitutes a cylinder structure in the block copolymer film of the present invention.

The two or more types of repeating monomer units are preferably aromatic vinyl and a conjugated diene partially or completely hydrogenated because it is easy to form a nonequilibrium morphology.
Such aromatic vinyl base monomers include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, t-butylstyrene, o-ethylstyrene, o-chlorostyrene, p-chlorostyrene. O, p-dichlorostyrene, p-bromostyrene, 2,4,5-tribromostyrene, and the like. Among these, styrene is particularly preferable because it is available at the lowest cost.
Further, the conjugated diene in the present invention originates from a monomer having a conjugated double bond in the same molecule, and the monomer serving as the base of the conjugated diene is not particularly limited. The conjugated diene may be incorporated into the main chain of the polymer molecule (1-4 bond) or incorporated into the branched chain (1-2 bond), but the ratio of both in the polymer molecule is There is no particular limitation. As the monomer used as the base of the conjugated diene, butadiene, isoprene, and styrene-butadiene random copolymer are suitable. In the present invention, a partially or completely hydrogenated conjugated diene as a repeating monomer unit is blocked by a conventional hydrogenation method of a conjugated diene polymer (for example, see JP-A-62-207303). It can be introduced into the copolymer.
In the present invention, the aromatic vinyl unit is a unit derived from styrene, and the unit of the conjugated diene partially or completely hydrogenated is particularly preferably a unit derived from butadiene.

  It is important that the block copolymer of the present invention has a molecular weight that is at least greater than the molecular weight at which microphase separation is possible and that it is easy to achieve a thermodynamic equilibrium or quasi-equilibrium state. From such a viewpoint, the number average molecular weight is preferably in the range of 10,000 to 1,000,000. The number average molecular weight is more preferably 20,000 or more, further preferably 30,000 or more, and particularly preferably 50,000 or more. The number average molecular weight is more preferably 750,000 or less, further preferably 500,000 or less, and particularly preferably 200,000 or less.

The block copolymer film of the present invention has a cylinder structure oriented in a direction perpendicular to the film surface. That is, an important feature of the present invention includes that the block copolymer film has a cylinder structure and the cylinder structure is oriented in a direction perpendicular to the film surface. By imparting such a feature to the block copolymer film, it is possible to design a highly functional material in a wide range of materials as described above.
Another important feature of the present invention is that the film thickness is in a specific range of 0.1 μm to 50 mm. By adopting the production method of the present invention described later, a block copolymer film suitable for each of the above-mentioned highly functional materials, which could not be obtained in the past, and more practical and relatively thick is manufactured. Became possible. The film thickness is preferably 1 μm or more, more preferably 5 μm or more, still more preferably 10 μm or more, and particularly preferably 0.1 mm or more. Moreover, it is preferable that a film thickness is 30 mm or less, More preferably, it is 10 mm or less, More preferably, it is 5 mm or less.

  In the present invention, the film thickness can be measured by selecting an appropriate method according to the size range. For example, X-ray or neutron reflectivity measurement (about 100 nm or less), atomic force microscope (about 1 μm or less), ellipsometry (about 1 μm or less), optical microscope (about 10 μm or more), and the like can be mentioned.

  In the present invention, it is extremely important that the film thickness and the disorder of the orientation angle, which will be described later, are closely related to each other, and that both satisfy the configuration defined in the present invention. In other words, it is important to consider the film thickness when defining the disorder of the orientation angle as a condition for the vertically aligned cylinder to penetrate the film. For example, when the film thickness is large, the vertically aligned cylinder does not penetrate the film unless the disturbance of the orientation angle is reduced. More specifically, the condition that the absolute value of the disorder of the orientation angle is smaller than a predetermined value (for example, 9 °) is that a film having a predetermined film thickness (for example, 10 μm) or more having sufficient mechanical strength to withstand practical use. Can be an important condition.

In the present invention, from the viewpoint of reducing the disorder of cylinder orientation on the film surface, the absolute value of the orientation angle disorder (defined by the half-width at half maximum by two-dimensional small-angle X-ray scattering measurement) with respect to the vertical orientation of the cylinder structure is It is less than 9 °. Disturbance of the orientation angle is obtained when measuring an edge image obtained when measuring two-dimensional small-angle X-ray scattering (SAXS), that is, when X-rays are incident parallel to the film surface from the film side surface. When the primary reflection peak intensity of the two-dimensional scattering pattern (Edge View Pattern) is plotted against the azimuth angle, the amount of change in the orientation angle when the azimuth angle is halved from the maximum peak intensity corresponding to the orientation angle of 180 ° Defined. Therefore, when the cylinder is oriented in a certain principal axis direction, the peak intensity appears at the maximum value at the azimuth angle position (180 ° in the vertical direction). (Half width) is regarded as disorder of the orientation angle. The absolute value of the disorder of the orientation angle is more preferably 7 ° or less, further 6 ° or less, and particularly preferably 5 ° or less. The lower limit of the absolute value of the disorder of the orientation angle that can be realistically achieved is about 2.5 °.
In the block copolymer film of the present invention, the cylinder structure is preferably arranged on a hexagonal lattice from the viewpoint of maximizing the number of vertically aligned cylinders.

In the block copolymer film of the present invention, the cylinder structure is composed of a cylinder having a diameter of 3 to 50 nm, and the magnetic nanodot number density is indispensable for increasing the amount of information that can be stored as a storage medium. It is preferable from the viewpoint of improving, improving the performance of the separation function, and increasing the surface area of the nanoreaction field (catalyst). The diameter of the cylinder is more preferably 3 to 20 nm. Further, such cylinders are preferably arranged at a distance of 5 to 120 nm, more preferably 5 to 50 nm, from the viewpoint of maximizing the number of vertically aligned cylinders. The cylinder diameter and the distance between the cylinders can be measured by observation with a transmission electron microscope, a small-angle X-ray scattering method, or the like.
In the block copolymer film of the present invention, the component constituting the cylinder structure is preferably a polymer component formed from repeated monomer units A as described above, that is, a polymer component in a glassy state at 23 ° C. .

Next, a preferred method for producing the block copolymer film of the present invention will be described in detail.
In the production of the block copolymer film of the present invention, preparation of a block copolymer sample using a special solvent and heat treatment by precise temperature control are important. In this case, it is particularly important to use a specific block copolymer sample in combination with a specific selective solvent.
Using a block copolymer sample (for example, styrene-ethylenebutylene-styrene triblock copolymer: SEBS) that can essentially form a cylindrical microphase-separated structure, a spherical microphase is obtained by a special method described below. A separation structure is formed. This is precisely performed at a temperature higher than the glass transition temperature of the glass component (in this case, polystyrene component) in the block copolymer, preferably at a temperature 100 ° C. higher than the glass transition temperature of the polymer component constituting the cylinder ( Preferably, the heat treatment is performed so that the temperature of the heat treatment sample is uniform, and the spherical structure can be united and changed into a cylinder structure. It can be oriented perpendicular to the film surface.

  The special method includes dissolving the block copolymer sample in a selective solvent (eg, heptane in this case). For example, when SEBS is used as the block copolymer, heptane has the ability to dissolve the polyethylene butylene component but has a low ability to dissolve polystyrene. When such a selective solvent is used as a solvent and adjusted to a predetermined polymer concentration (preferably 1 to 5% by weight), the solvent is excessively distributed in the polyethylene butylene phase in the solution. Therefore, in the solution, it is possible to make the polyethylene butylene phase excessive and the polystyrene phase excessively smaller than the original composition of the sample. As a result, the polystyrene phase forms a spherical structure (spherical domain) in the solution. When the solvent is gradually evaporated from this state, the polymer concentration increases, and the polystyrene phase is vitrified and the sphere structure is frozen. Since the spherical structure is maintained up to this stage, the spherical structure that should not originally be formed is frozen in the cast film obtained by completely evaporating the solvent.

  Here, it is important to perform the heat treatment under precise temperature control. For example, the temperature is higher than the glass transition temperature of polystyrene (for example, 150 ° C.), preferably higher than the glass transition temperature of the polymer component constituting the cylinder by 80 ° C. or higher, more preferably higher by 90 ° C. or higher. Is a temperature higher than 100 ° C., particularly preferably higher than 100 ° C., precisely (preferably with a temperature accuracy of ± 1 ° C., more preferably with a temperature accuracy of ± 0.5 ° C.) for a predetermined time (for example, 10 Time), for example, in a silicone oil bath, heat treatment is performed so as to achieve as uniform a temperature distribution as possible so as not to cause uneven temperature and temperature gradient. As a result, the spherical structure is united to be changed into a cylinder structure, and a cylinder structure oriented in a direction perpendicular to the film surface is formed. The structure before merging is preferably a spherical structure that forms a body-centered cubic lattice from the viewpoint of easy transfer to the cylinder. Further, it is preferable that the structure before merging is a spherical structure in which a distorted anisotropic body-centered cubic lattice that is contracted in the film thickness direction is assembled, from the viewpoint of reducing disorder of the orientation angle of vertical alignment.

Accordingly, the present invention also provides a microphase-separated structure formed from a block copolymer that is merged in a direction perpendicular to the film surface and transferred to a cylinder structure in a direction perpendicular to the film surface. The present invention also relates to a method for producing a block copolymer film having an oriented cylinder structure. In such a production method, the transition from the spherical microphase separation structure to the cylinder structure is preferably caused by the self-organization ability of the block copolymer.
Further, the present invention is a method for producing the block copolymer film,
(A) adding a selective solvent to the block copolymer to form a polymer solution;
(B) then forming an as-cast membrane having a nonequilibrium morphology by removing the selective solvent from the polymer solution;
(C) forming a cylinder structure by subjecting the as-cast film to a heat treatment;
Relates to a method comprising:

Here, the selective solvent refers to a solvent that corresponds to a selective good solvent for a certain type of polymer component and corresponds to a selective poor solvent for another type of polymer component. The non-equilibrium morphology refers to a form other than the form of the microphase separation structure that is a block copolymer alone (not including any solvent or additive) and stably exists above the glass transition temperature.
Moreover, when removing this selective solvent from a polymer solution, it is preferable to concentrate a polymer solution and to completely evaporate a selective solvent to make an absolutely dry as-cast membrane.

In the above-mentioned method, it is preferable to use a solvent corresponding to a selective poor solvent for the polymer component forming the cylinder and a solvent corresponding to the selective good solvent for the polymer component forming the matrix.
Here, the polymer component (glass component) formed from the repeating monomer unit A corresponds to a selective poor solvent, and the polymer component (for example, rubber component) formed from at least one other repeating monomer unit B. It is preferable to use a solvent corresponding to a selective good solvent. Here, the selective good solvent means the following formula using a solubility parameter δ:
(Δ _solvent −δ _polymer ) / δ _solvent
The absolute value of the value obtained from the above means a solvent smaller than 0.1, and the selective poor solvent means a solvent whose absolute value is larger than 0.1. For the method of measuring the solubility parameter δ and the measured values for typical polymers and solvents, see, for example, the Polymer Handbook (Polymer Handbook, 3rd edition, edited by J. Brandrup & EH Immergut, Wiley, New York, 1989). Are listed.
Further, it is preferable to use a mixed solvent further containing one or more solvents corresponding to the common solvent for the block copolymer as the solvent, from the viewpoint of uniformly dissolving the polymer sample. Examples of such a further solvent include methylene chloride.

  When the heat treatment is performed at a temperature equal to or higher than the glass transition temperature of the polymer component constituting the spherical structure in the as-cast film, a block copolymer film having a cylinder structure oriented in a direction perpendicular to the film surface is obtained. It is effective for.

According to the present invention, as described above, high-performance materials can be designed in a wide range of fields. Examples of highly functional materials include nanowires, nanostamps, nanoporous materials, nanoporous hollow fibers, nanoporous tubes, and the like. Such high-functional materials include, for example, high-performance optical materials such as electronic information recording media and optical retardation films, adsorbents, nano-reaction field membranes, catalysts, high-function membranes (nano-reaction fields, catalysts, separation membranes), high-performance materials. It can be used for applications such as functional hollow fibers, high performance tubes, nano templates, and nano molds.
In the present invention, the optical material includes a polarizing plate protective film, a quarter-wave plate, a half-wave plate and the like used for a display such as a liquid crystal display, a plasma display, an organic EL display, a field emission display, and a rear projection television. A retardation plate, a liquid crystal optical compensation film such as a viewing angle control film, a display entire surface plate, a display substrate, a lens, and a transparent substrate used for a solar cell or the like are included. The block copolymer film of the present invention can be particularly suitably used for these optical materials.

  For example, it is possible to obtain a nanoporous material by decomposing or dissolving the cylinder structure formed in the block copolymer film of the present invention. The decomposition method is not particularly limited, and a conventionally known method can be adopted. For example, methods such as ion beam etching and ozone decomposition treatment are recommended. Also, the dissolution method is not particularly limited, and a conventionally known method can be adopted. For example, a solvent capable of dissolving only one of the polymers forming the cylinder or the matrix (for example, a glass component dissolves but a rubber component is dissolved). A method using a solvent that does not dissolve, a solvent that dissolves the rubber component but does not dissolve the glass component, and a method that uses an acid or an alkali are recommended. The nanoporous material thus obtained has pores with a size of about 1 to 100 nm, for example.

An example of the method in the case of using the nanoporous material in the present invention as an adsorbent, a catalyst, or a separation membrane is shown below.
1. Selectively etch with a solvent that dissolves only the vertically oriented cylinder or ozonolysis.
By decomposing and removing only the components that form the cylinder, holes having a diameter of about 3 to 50 nm can be penetrated.
2. Chemical affinity is expressed by applying chemical treatment to the inner wall surface of the through hole.
Then, it becomes possible to extract only a specific component from the mixture gas separation or solution.
3. First, a specific molecule is adsorbed on the wall surface of the through hole, and then a molecule that causes a chemical reaction with the molecule is allowed to permeate through the through hole, thereby providing an action as a catalyst.
Since the through-hole obtained by the present invention is very small in itself, the area of the wall surface of the through-hole can exist at a considerably large ratio per unit volume. Accordingly, it is expected that the catalyst efficiency is considerably high and the reaction time is drastically shortened.

  Moreover, if it removes by decomposing | dissolving or melt | dissolving a matrix phase from the block copolymer film | membrane of this invention, a nanowire can be obtained. The decomposition method is not particularly limited, and a conventionally known method can be adopted. For example, a method such as ozone decomposition or ion beam etching is recommended. Also, the dissolution method is not particularly limited, and a conventionally known method can be adopted. For example, a solvent capable of dissolving only one of the polymers forming the cylinder or the matrix (for example, a glass component dissolves but a rubber component is dissolved). A method using a solvent that does not dissolve, a solvent that dissolves the rubber component but does not dissolve the glass component, and a method that uses an acid or an alkali are recommended. The nanowire thus obtained is an elongated wire-like material having a diameter of about 1 to 100 nm and has a length corresponding to the film thickness. Nanowires imparted with conductivity by using a conductive polymer are extremely useful.

When a metal is vapor-deposited on the nanoporous material obtained as described above and the pores and the film surface are covered with a vapor deposition layer, the block copolymer film is decomposed or dissolved to obtain a nano stamp. According to the present invention, a stamp (nano stamp) having a pattern engraved with an accuracy of about 1 to 100 nm can be obtained. Such a nano stamp can be suitably used for transferring a pattern onto the surface of a substrate. The nano stamp may have a roller shape.
A magnetic recording medium capable of high-density recording can be obtained by bringing the obtained nanostamp into a magnetic solution and pulling it up and then bringing it into contact with the substrate surface.
The nanoporous material obtained as described above can be suitably used as a template for a structure formed three-dimensionally with an accuracy of about 1 to 100 nm as a nanotemplate.

  Hereinafter, the effectiveness of the present invention will be described with reference to examples, but the present invention is not limited thereto. In addition, the evaluation method of the physical property in the following examples is as follows.

1. Disturbance of orientation angle Disturbance of the orientation angle with respect to the vertical orientation of the cylinder structure was measured according to the following method.
Disturbance of the orientation angle is obtained when measuring an edge image obtained when measuring two-dimensional small-angle X-ray scattering (SAXS), that is, when X-rays are incident parallel to the film surface from the film side surface. When the primary reflection peak intensity of the two-dimensional scattering pattern (Edge View Pattern) is plotted against the azimuth angle, the amount of change in the orientation angle when the azimuth angle is halved from the maximum peak intensity corresponding to the orientation angle of 180 °. evaluated. Specifically, when the cylinder is oriented in a certain principal axis direction, a peak intensity appears at the maximum value at the position of the azimuth angle (180 ° in the vertical direction). Half (half width at half maximum) was regarded as disorder of the orientation angle.
Measurements were performed using X-ray beam size at the sample position of 1.0 mm in the horizontal direction, 0.7 mm in the vertical direction (rectangular beam cross section), wavelength of 0.1499 nm, and synchrotron radiation science from the High Energy Accelerator Research Organization (Tsukuba). This was performed using an imaging plate (Fujifilm) at the beam line BL-9C of the research facility. For reading, Fuji BAS2000 was used. The resolution (size) of one pixel was 100 μm × 100 μm.

2. Distance between cylinders The distance between cylinders was measured according to the following method.
Small angle X-ray scattering measurement was performed, the scattering angle dependence of the scattering intensity was plotted, and the scattering angle θ was determined from the position of the primary peak of the lattice scattering factor that appears (the peak that appears at the position where the scattering angle is the smallest). This is Bragg's reflection condition formula:
2d · sin (θ / 2) = nλ
(Where d is the spacing between the reflecting surfaces, θ is the scattering angle, n is a natural number, and λ is the X-ray wavelength)
By substituting into, the distance d between the reflecting surfaces was obtained. Relation between d and distance L between cylinders:
L = (2/3 ^0.5 ) × d
Was used to determine the distance between the cylinders.

3. Cylinder diameter The cylinder diameter was measured according to the following method.
A plot of the scattering angle dependence of scattering intensity, the position of the first peak of appearing particles scatter factor, was determined its scattering angle theta _p. This is the formula:
(4π / λ) sin (θ _p /2)=4.98/R
And the cylinder radius R was calculated.

[Example 1]
As the block copolymer, styrene-ethylenebutylene-styrene triblock copolymer (SEBS) (Tuftec (registered trademark) H1062 manufactured by Asahi Kasei Chemicals Corporation) was used. The sample has a volume fraction of polystyrene (PS) of 0.16, a number average molecular weight (M _n ) of 6.6 × 10 ⁴ , a polydispersity index (M _w / M _n ) of molecular weight distribution of 1.03, in a polyethylene butylene (PEB) chain The butylene chain had a mole fraction of 0.41. The sample was prepared using a mixed solvent with a 1: 1 volume ratio of heptane, which is a good solvent, and methylene chloride, which is a common solvent, selectively with respect to PEB so that the polymer concentration is 5% by weight. A block copolymer film (as-cast sample) was prepared by putting in a petri dish and evaporating the solvent at 23 ° C. Heptane was (δ _solvent −δ _polymer ) / δ _solvent = 0.095 for PEB and (δ _solvent −δ _polymer ) / δ _solvent = 0.257 for PS.
This as-cast sample was heat-treated at 210 ° C. for 3 hours in silicone oil and quenched in ice water (the obtained sample is referred to as an as-annealed sample). Two-dimensional small-angle X-ray scattering (SAXS) measurements were performed on these samples at BL-9C of the High Energy Accelerator Research Organization.

FIG. 1 shows a two-dimensional SAXS pattern (edge view) obtained for (a) as-cast sample and (b) as-annealed sample. N in the figure indicates the normal direction of the film. The scale bar indicates the magnitude q of the scattering vector, and q = (4π / λ) sin (θ / 2). Here, λ is the wavelength and θ is the scattering angle.
FIGS. 2A and 2B show one-dimensional SAXS profiles obtained from the two-dimensional SAXS patterns of the (a) as-cast sample and (b) as-annealed sample in FIG. 1, respectively. Because the relative ratio of the higher order peak to the primary peak is 1: √2: √3 for (a) as-cast sample and 1: √3: √4 for (b) as-annealed sample. It can be seen that the transition from the spherical structure to the cylindrical structure occurs before and after the heat treatment.
In addition, the regular bcc (body centered cubic lattice) array formed by the sphere structure is distorted in the as-cast sample in Fig. 1 (a) because the scattering peak is elliptical (especially shrinks in the thickness direction). I understand).
On the other hand, in the as-annealed sample in FIG. 1 (b), the peak appears in a spot shape only in the meridian direction, and the result is that the cylindrical structure is oriented perpendicular to the film surface. This is thought to be because the coalescence of spheres occurred preferentially only in the direction perpendicular to the film surface.

In FIG. 3, the observation result of a transmission electron microscope (TEM) is shown.
From the block copolymer film (as-annealed sample) obtained in Example 1, an ultrathin slice having a thickness of 80 nm was obtained at a cutting temperature of -85 ° C to -90 ° C using an ultramicrotome. The sections were stained with ruthenium tetroxide. Observation was performed by operating an Hitachi electron microscope H-600 at an acceleration voltage of 75 kV.
The dark area in the figure is the stained polystyrene phase. On the other hand, the bright areas are undyed polyethylene butylene phases. The through image shows a circular cross section of a polystyrene cylinder. It can also be seen that the cylinders are regularly arranged on a hexagonal lattice. In the edge image, it can be seen that the cylinders lying in the horizontal direction are repeatedly arranged in a one-dimensional direction (up and down direction on the paper surface).
These transmission electron microscope observations confirmed that the cylinder was oriented perpendicular to the film surface.

FIG. 4 is a diagram showing the normalized scattering intensity of the primary peak as a function of the azimuth angle from the edge image result of the two-dimensional small-angle X-ray scattering of the block copolymer films obtained in Examples and Comparative Examples. It is.
That is, FIG. 4 is a plot of the azimuth dependence of the primary peak scattering intensity from the two-dimensional small-angle X-ray scattering image shown in FIG. Here, the azimuth angle was positive in the clockwise direction with respect to the 12 o'clock direction of the watch. The vertical axis represents the normalized scattering intensity. The normalized scattering intensity is a value obtained by dividing the scattering intensity by the value of the scattering intensity at an azimuth angle of 180 °. Therefore, the normalized scattering intensity takes a value of 1.0 at an azimuth angle of 180 °. A sharp peak means less disturbance from vertical alignment. The angle described in the annotation box in the figure indicates the half width of the peak. Therefore, half of this value is the degree of disturbance (± value) from the vertical.

  The film thickness of the block copolymer film (as-annealed sample) obtained in Example 1 is 0.3 mm, the disorder of the orientation angle is 4.25 °, the cylinder diameter is 13.2 nm, and the distance between the cylinders is 30.2 nm. A film material useful as an optical retardation film having birefringence in the film thickness direction was obtained.

[Comparative Example 1]
A block copolymer membrane (as-annealed sample) was prepared in the same manner as in Example 1, except that the heat treatment in silicone oil was changed to 150 ° C. × 10 hours instead of 3 hours at 210 ° C. )
The resulting block copolymer film (as-annealed sample) has a film thickness of 0.3 mm, disordered orientation angle of 9 °, cylinder diameter of 13.2 nm, and distance between cylinders of 30.2 nm. It was an insufficient film material as an optical retardation film having refractive properties.

[Example 2]
A block copolymer membrane (as-annealed sample) was prepared in the same manner as in Example 1, except that the heat treatment in silicone oil was changed to 180 ° C. × 3 hours instead of 3 hours at 210 ° C. )
The resulting block copolymer film (as-annealed sample) has a film thickness of 0.3mm, disordered orientation angle of 7 °, cylinder diameter of 13.2nm, and distance between cylinders of 30.2nm. Film material was obtained.

[Comparative Example 2]
In Example 1, a block copolymer film having a film thickness of 0.3 mm was formed in the same manner as in Example 1 except that a cylinder was formed from the beginning without forming a sphere by casting using toluene as a solvent. Obtained.
In the obtained block copolymer film, the process of coalescence of the spherical structure was not performed, so that the cylinder was not vertically aligned even when the same heat treatment as in Example 1 was performed. Therefore, it was quite insufficient as a material that the nanocylinder needs to penetrate the membrane.

[Comparative Example 3]
Three layers of films obtained according to Comparative Example 2 were stacked without using a method of using a sphere coalescence process (initial thickness: 0.9 mm, initial length: 3 mm), and in addition, a flow field in one direction. To give a block copolymer film (final thickness: 0.45 mm, final length: 6 mm). The flow field was applied for 20 seconds at 150-210 ° C. under a load of 1065 g. A spacer was used to fix the final film thickness.
In the obtained block copolymer film, orientation occurred parallel to the direction of the applied flow field, but it is impossible to give a flow field perpendicular to the film surface. could not. Therefore, it was quite insufficient as a material that the nanocylinder needs to penetrate the membrane.

According to the present invention, it is possible to easily produce a block copolymer film having a cylinder structure that is oriented in a direction perpendicular to the film surface and has a small disorder of the orientation angle.
According to the present invention, high-performance materials can be designed in a wide range of fields. Examples of highly functional materials include nanowires, nanostamps, nanoporous materials, nanoporous hollow fibers, nanoporous tubes, and the like. Such high-performance materials include, for example, electronic information recording media, high-performance optical materials, adsorbents, nano-reaction field membranes, catalysts, high-performance membranes (nano-reaction fields, catalysts, separation membranes), high-performance hollow fibers, and high-performance tubes. It can be used for applications such as nano template and nano mold.

FIG. 1 is a diagram showing a two-dimensional SAXS pattern (edge view) obtained for (a) as-cast sample and (b) as-annealed sample in Example 1. FIG. 2 is a diagram showing one-dimensional SAXS profiles obtained from the two-dimensional SAXS patterns of (a) as-cast sample and (b) as-annealed sample in FIG. In FIG. 3, the observation result of the transmission electron microscope (TEM) of the block copolymer film obtained in Example 1 is shown. FIG. 4 is a diagram showing the result of two-dimensional small-angle X-ray scattering (the azimuth angle dependence of the scattering intensity of the primary peak).

Claims (25)

  The absolute value of the disorder of the orientation angle with respect to the vertical orientation is 0.1 μm to 50 mm, oriented in the direction perpendicular to the film surface, and defined by the half width at half maximum by two-dimensional small-angle X-ray scattering measurement. A block copolymer film having a cylinder structure of less than 9 °.   The block copolymer film according to claim 1, wherein the cylinder structure is arranged on a hexagonal lattice.   The block copolymer according to claim 1 or 2, wherein the block copolymer comprises two or more types of repeating monomer units, and the polymer component formed from at least one type of repeating monomer units A is in a glass state at 23 ° C. film.   The block copolymer film according to any one of claims 1 to 3, wherein a volume fraction of the polymer component formed from the repeating monomer unit A with respect to the block copolymer is 0.1 to 0.4.   The block copolymer film according to claim 4, wherein the component constituting the cylinder structure is a polymer component formed from repeating monomer units A.   The block copolymer film according to claim 1, wherein the cylinder structure is a cylinder having a diameter of 3 to 50 nm.   The block copolymer film according to claim 6, wherein the cylinders are arranged at a distance of 5 to 120 nm.   The block copolymer film according to any one of claims 3 to 7, wherein the at least two kinds of repeating monomer units are an aromatic vinyl unit and a conjugated diene unit partially or completely hydrogenated.   The block copolymer film according to claim 8, wherein the aromatic vinyl unit is a unit derived from styrene, and the unit of the conjugated diene partially or completely hydrogenated is a unit derived from butadiene.   The block copolymer film according to claim 1, wherein the block copolymer has a number average molecular weight of 10,000 to 1,000,000.   The block copolymer film according to any one of claims 1 to 10, wherein the absolute value of the disorder of the orientation angle with respect to the vertical orientation is 7 ° or less.   The nanoporous material formed by the said cylinder structure in the block copolymer film in any one of Claims 1-11 being vacated by decomposition | disassembly or melt | dissolution.   A catalyst comprising the nanoporous material according to claim 12.   A nanostamp obtained by vapor-depositing a metal on the nanoporous material according to claim 12 and covering the pores and the film surface with a vapor deposition layer, and then decomposing or dissolving the block copolymer film.   The nanostamp of claim 14 having a roller shape.   A magnetic recording medium obtained by bringing the nanostamp according to claim 14 or 15 into contact with a surface of a substrate after being dipped in a magnetic material solution and pulled.   A nanowire obtained by removing the matrix phase from the block copolymer film according to any one of claims 1 to 11 by decomposition or dissolution.   Cylinder structure oriented in a direction perpendicular to the membrane surface, comprising merging a spherical structure in a microphase-separated structure formed from a block copolymer into a cylinder structure by merging in a direction perpendicular to the membrane surface A method for producing a block copolymer film having   The block according to any one of claims 1 to 11, comprising transferring the spherical structure in the microphase-separated structure formed from the block copolymer into a cylinder structure by merging in a direction perpendicular to the membrane surface. A method for producing a copolymer film.   The method for producing a block copolymer film according to claim 18 or 19, wherein the transition from the spherical structure to the cylinder structure is caused by the self-assembly ability of the block copolymer. It is a manufacturing method of the block copolymer film according to any one of claims 1 to 11,
(A) adding a selective solvent to the block copolymer to form a polymer solution;
(B) then forming an as-cast membrane having a nonequilibrium morphology by removing the selective solvent from the polymer solution;
(C) forming a cylinder structure by subjecting the as-cast film to a heat treatment;
A method comprising that.   The solvent corresponds to a selective poor solvent for the polymer component formed from the repeating monomer unit A, and is a selective good solvent for the polymer component formed from at least one other repeating monomer unit B. The method of Claim 21 using the solvent corresponded to.   The method according to claim 22, wherein the solvent is a mixed solvent further containing one or more solvents corresponding to a common solvent for the block copolymer.   The method according to any one of claims 21 to 23, wherein the heat treatment is performed at a temperature equal to or higher than a glass transition temperature of a polymer component constituting the cylinder.   The method according to any one of claims 21 to 23, wherein the heat treatment is performed at a temperature higher than the glass transition temperature of the polymer component constituting the cylinder by 100 ° C or more and with a temperature accuracy of ± 1 ° C.

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