JP2005262777A - Method for production of high quality honeycomb structure film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high quality porous film which has no crystal defect by improving hole periodicity in a honeycomb film. <P>SOLUTION: The method for production of a thin film (honeycomb film) having holes arranged in a honeycomb form comprises imparting vibration of definite cycle to a raw material solution for film formation or a substrate for this purpose in production of the honeycomb film by casting on the substrate under high humidity condition, controlling the size and arrangement of water droplets being a template by controlling the vibration, and restraining or eliminating generation of abnormal droplet particles to produce the film having uniform honeycomb structure holes. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a high-quality honeycomb structure thin film body having fine honeycomb structure holes arranged uniformly. Specifically, in a method for manufacturing a thin film structure (honeycomb film) having pores arranged in a honeycomb shape, that is, a porous honeycomb structure thin film structure (hereinafter referred to as a honeycomb film), fine pores arranged in a honeycomb shape Relates to a method for manufacturing a porous honeycomb film that is regularly arranged in a uniform size.

  In recent years, technological development at the nanoscale level has been actively carried out, and the importance of ultraprecision machining and ultraprecision control has been increasingly demanded. This trend is not limited to cell culture engineering, medical scaffold materials, semiconductors, recording materials, screens, separators, ion exchange membranes, battery membrane materials, displays, optical materials, waveguides, acoustic equipment materials, and other various technical fields. This is particularly noticeable, and expectations for ultra-precise technology development are increasing. The porous membrane which is the subject of the present invention is no exception. In other words, the porous membrane targeted by the present invention naturally includes applications used in the above-mentioned fields, and therefore, the design must reflect the trends in the above-mentioned fields and meet the requirements. In addition, a high degree of design is required to ensure the distribution and uniformity of the pores forming the membrane structure.

  The use of porous membranes is diverse, but in recent years, the creation of new technologies is being considered using highly designed films with fine pores. In particular, in the fields of electronics, photonics, and biotechnology, there is a need for high quality films having uniform and regularly arranged holes. However, it is not easy to produce such a porous film, and it is difficult to secure uniform pores by a film forming technique using a normal stretching method. Even with a porous film forming technique based on a phase separation method known as a relatively simple production method, it is difficult to obtain a uniform pore size and a regular arrangement by controlling the pore diameter and the arrangement thereof. On the other hand, lithographic techniques such as photolithography, soft lithography, and nanoimprint lithography are used as a method for producing a microstructure having a uniform pore size and arrangement. However, it requires advanced and expensive equipment and technology, and costs are low. Production methods using this method are also suitable for providing a porous film at a practical level, such as being expensive, requiring complicated processes that require many man-hours, and limitations on applicable materials. It could not be said.

  On the other hand, various literatures have recently reported and proposed that a fine regular pattern can be formed relatively easily by casting a dilute solution of a polymer on a solid substrate. This has already been proposed and succeeded in the research group of the present inventors (see Non-Patent Document 1). In this method, a dilute solution of a polymer is cast, and a solvent is evaporated to form a fine-structure dot (projection) pattern on the polymer. However, the method according to this proposal has not yet reached a microdot with regularity so that the arrangement of the protrusions can be controlled, and is insufficient.

  It has also been proposed to form a porous film having a fine honeycomb pattern different from the dot structure as the fine structure (Non-patent Documents 2 and 3). This method uses a special polymer that has both a strong self-aggregating part and a flexible part, and the polymer is dissolved in a hydrophobic organic solution and cast to form the pattern. is there.

In addition, as a result of earnest research in the present inventors group, this method was also successful in producing a microstructure having a unique honeycomb structure by selecting a specific polymer as a polymer to be cast. The results were announced and reported in technical papers (Non-Patent Document 4, Non-Patent Document 5).
That is, as a constituent component of the polymer, an amphiphilic polymer having a hydrophilic acrylamide polymer as a main chain skeleton, a dodecyl group as a hydrophobic side chain and a lactose group or a carboxyl group as a hydrophilic side chain, or heparin or dextran sulfate. By using an ionic complex of an anionic polysaccharide such as quaternary long-chain alkylammonium salt, a porous thin film having a honeycomb pattern structure has been successfully produced.

The present inventors have also found that a porous honeycomb structure film made of various biodegradable polymers is a very promising material as a cell culture substrate, and applied for a patent based on this. (See Patent Document 1).
In this patent application, the production method proposed by the present inventors is extremely simple and inexpensive, in that it is produced simply by spraying high humidity air onto a cast film of a hydrophobic organic solution whose concentration has been adjusted, or simply placing it in high humidity. Indeed, it is an excellent technique with very attractive advantages.
In this method, the pore diameter of the porous membrane can be controlled in the range of 0.1 to 100 μm by changing the diameter of the water droplet that becomes the mold of the pore during the production process. It can be said that it is an extremely excellent proposal.

  However, even in these methods, since the honeycomb film pores are arranged by water droplets carried by the cohesive force due to the transverse capillary force, they depend on the interfacial phenomenon between the individual water droplet particles and the solution. There were concerns about having defects and grain boundaries. However, it is virtually difficult to control and prevent defects in individual particles to deal with this. This was one of the factors that hindered application to materials that require high uniformity, such as electronic materials and optical materials.

Chemistry Letters, 821, 1996. Science 283, 373, 1999 Nature 369, 387, 1994 Thin Solid films 327, 829, 1998 Molecular Cryst. Liq. Cryst. 322, 305, 1998 JP 2001-157574 A

  Under such circumstances, the present invention provides a method for producing a thin film (honeycomb film) having pores arranged in a honeycomb shape from a cast of a hydrophobic organic solvent solution of an amphiphilic polymer. It is intended to improve the periodicity of the pores and provide a high-quality porous film free from crystal defects.

  In order to meet the above requirements, the present inventors have conducted extensive research on the development of means for reducing crystal defects in honeycomb films. As a result, a mixture of an amphiphilic polymer and a functional polymer was dissolved in a hydrophobic organic solvent. When manufacturing a honeycomb film by casting on a substrate under high humidity, the crystal defects are reduced and high quality by applying a constant period of vibration to the raw material solution that produces the film or the substrate that produces the film. And found that a honeycomb film can be obtained. The present invention has been made based on this finding, and the configuration thereof is as described in (1) to (9) below.

(1) When a hydrophobic organic solvent solution in which a mixture of a functional polymer and an amphiphilic polymer is dissolved is cast on a substrate in an atmosphere having a relative humidity of 50 to 95%, and the organic solvent is gradually evaporated. At the same time, moisture is condensed on the surface of the casting solution, and minute water droplets generated by the condensation are evaporated to form honeycomb-like pores using the water droplets as a template. A method for manufacturing a honeycomb film, comprising producing a honeycomb film while applying vibration to the substrate.
(2) The method for manufacturing a honeycomb film according to (1), wherein the frequency to be applied is appropriately adjusted within a range of 1 Hz to 500 Hz.
(3) A substrate on which a solution is cast is composed of a pair of substrates placed in parallel with a gap between which the solution is cast and brought into contact with both substrates while maintaining the contact state. The method for producing a honeycomb film according to the above (1), wherein the film is formed by moving the parallel movements.
(4) A nozzle that blows high-humidity air at the position where the solution is cast is set, and high-humidity air is blown against the cast raw material solution and the film to be produced, so that water droplets are condensed on the film surface. The method for manufacturing a honeycomb film according to any one of (1) to (3), which is characterized in that
(5) The means for applying vibration to the cast solution and the substrate is a piezo vibrator. By controlling the vibrator, the size and arrangement of water droplets are controlled, and the size and arrangement of the holes in the honeycomb film are controlled. The method for manufacturing a honeycomb film according to any one of (1) to (3), wherein
(6) The functional polymer according to any one of (1) to (5), wherein the functional polymer is one selected from biodegradable, photofunctional, and electronic functional materials. A method for manufacturing a honeycomb structure.
(7) The method for manufacturing a honeycomb structured body according to any one of (1) to (5), wherein the pore diameter of the honeycomb structured body is 0.1 to 50 µm.
(8) In a honeycomb film manufacturing apparatus using condensed water droplets as a template, a piezo vibrator is brought into contact with a substrate on which a film is generated, and is developed on the substrate and the substrate, and the film formed on the film and the minute on the film Gives microscopic vibrations to water droplets, eliminates the formation of abnormal particles in microscopic water droplets that condense on the film, and provides regularity and periodicity to the array of microscopic water droplets, thereby regulating the honeycomb-like pores formed in the film. A device for manufacturing a honeycomb film, characterized by providing the property and periodicity.
(9) The honeycomb film manufacturing apparatus according to (8), wherein the film generation substrate includes two parallel substrates that are installed with a gap and are relatively movable.

  The present invention is a honeycomb film manufacturing process using condensed water droplets as a template, or in a honeycomb film manufacturing apparatus that performs this process, a vibrator is brought into contact with a substrate on which a honeycomb film is generated, and vibration intensity, vibration period, By controlling the vibration application time, microvibration is applied to the film that develops on the substrate and the minute water droplets that are condensed on the film, thereby eliminating abnormal particles of the minute water droplets on the film, thereby uniform size The honeycomb film can be easily manufactured, and in the honeycomb film manufacturing technology, the uniformity and reproducibility of the film can be easily secured, and the manufacturing efficiency is dramatically increased. It contributed to this and provided extremely practical means, and its significance is great.

  The aspect of the manufacturing process of the high quality honeycomb film according to the present invention will be described in order as follows. First, several to several tens of g / L of a hydrophobic organic solvent solution of an amphiphilic polymer is dropped on a solid substrate, the organic solvent is evaporated in air having a relative humidity of 50% or more, and cooled with heat of vaporization. When water droplets are condensed on the surface of the solution, the water droplets are packed into the film solution by capillary force, and a polymer film is formed by evaporation of the solvent and evaporation of the water droplets. The holes arranged in the hexagonal are obtained. As described above, since the arrangement of the holes obtained by this process depends only on the capillary force, it is not always uniform, and abnormal droplets are generated in water droplets, and a large number of defects and grain boundaries are formed. As a result, it became clear that non-uniform honeycombs were formed.

  In general, it has been found in various systems that a periodic structure is formed by applying a constant frequency vibration to a particulate object. Therefore, the inventors considered that the minute water droplets that serve as the mold of the honeycomb film are also a kind of particles, and as a result of trying to impart vibrations at a constant frequency during the production of the honeycomb film, it has become clear that they are effective.

  In order to produce a uniform honeycomb film with such vibration, it is preferable to prepare and use the following apparatus. First, it is preferable to prepare the apparatus shown in FIG. 1 in order to carry out a method for continuously producing a honeycomb film while applying vibration. This apparatus is composed of a pair of substrate devices. One of them is a first substrate device in which a first substrate is mounted horizontally on a first substrate stand that is erected and fixed. In contrast to the first substrate device, the second substrate device is: Preferably, the second horizontal substrate is configured to be movable in the horizontal direction, and the setting position of the second horizontal substrate is set to be finely adjustable in the vertical direction. Furthermore, the honeycomb manufacturing apparatus includes a vibration element that applies vibration to these substrates, and further includes a mechanism and a control device for controlling the relative position, interval, and operation of the substrate device. Is preferred. These device designs and honeycomb film manufacturing processes using these devices are all included as aspects of the present invention.

  A preferred procedure for producing a honeycomb film using the above apparatus is as follows. First, the second substrate device is brought closer to the substrate set as the first substrate device, and the substrate position is controlled so that a gap between the opposing substrates forms a gap suitable for film production. Prepare. The substrate is provided with a vibrator for applying vibration, for example, a piezo element. The piezoelectric element amplifies an electric signal generated by a function generator (not shown) by an amplifier and vibrates at a specified frequency based on the electric signal. In general, the gap between the two substrates is preferably set in the range of 0.1 to 1 mm. A film is continuously formed by casting a predetermined amphiphilic polymer solution into this gap, bringing it into contact with both substrates, and slowly moving both substrates in parallel and relatively away from each other. The moving speed of the substrate is usually preferably separated at a speed of 0.01 to 2 mm / s. At this time, it is preferable to blow high-humidity air on the solution interface formed at the edge of the substrate to form a honeycomb film and simultaneously apply vibration of 10 to 500 Hz by a piezo element. When a honeycomb film is formed in a batch manner, it is preferable to place a piezo element on the substrate or abut on the surface opposite to the film forming surface. That is, it is preferable to cast and evaporate the solvent in the same manner with vibration applied. The present invention includes these embodiments.

In addition, as the polymer used in the present invention, there is basically no restriction on the material used, and it may be selected according to the application. If the application of the honeycomb filter of high quality according to the present invention is used in the fields of electronics, photonics, and biotechnology, it is a single amphiphilic material having electronic functionality, optical functionality, and biocompatibility. Molecules may be used, or an amphiphilic polymer may be mixed with these functional polymers. The present invention includes all of them as aspects of the invention. More specifically, a preferred polymer may be an amphiphilic polymer represented by (Chemical Formula 1) and another functional polymer in a weight ratio of 1:10 or more. Moreover, what made water-soluble polymer dispersible in an organic solvent by the polyion complex method etc. can also be used. Furthermore, it can be used for fluorine-based polymers having fluorine-based residues and other polar residues.

  Furthermore, the organic solvent used in the present invention is not particularly limited as long as it is a volatile organic solvent insoluble in water and having a low boiling point. Specifically, halogenated hydrocarbons such as dichloromethane and chloroform, aromatic hydrocarbons such as benzene, toluene, and xylene, and fluorine-based organic solvents can also be used. In any case, these solvents need to be handled with care and must be environmentally friendly. Therefore, it is preferable to carry out these solvents at a solvent recovery facility equipped with a draft. Alcohol and acetone are water-soluble and cannot be used.

  Furthermore, the substrate used in the present invention is not particularly limited, but is preferably made of an inorganic material such as ITO, glass, metal, silicon wafer, or the like, or made of an organic solvent resistant material such as polypropylene, polyethylene, polyetherketone or fluororesin. A polymer having excellent resistance can be preferably used.

  The present invention will be described in more detail with reference to the following examples. However, these examples are illustrative and do not limit the present invention in any way.

Example 1;
Amphiphilic polymer (Chemical Formula 2) and polystyrene (Mw = 280,000, Aldrich) were mixed at 9: 1 to prepare chloroform solutions with concentrations of 5.0 g / L, 10 g / L, and 20 g / L. A honeycomb film was formed using the apparatus shown in FIG. 1 while applying vibration in the range of 10 to 150 Hz. 700 μL of each solution was injected into the gap between the two glass substrates, and one of the substrates was pulled apart at 500 μm / s. At this time, high-humidity air was blown onto the solution interface formed at the edge of the substrate with an air pump.

  It was observed that the film produced under the above conditions exhibited various interference colors when white light was applied. This indicates that there are grain boundaries of various sizes and crystal directions in the film. However, when the solution concentration was 20 g / L, the periodicity was extremely deteriorated, resulting in an irregular pore size. When the surface structure was observed with an optical microscope and an electron microscope, a honeycomb structure was formed at any vibration frequency (FIG. 2). However, as a result of examining the periodicity of the arrangement, it became clear that the frequency dependence was shown.

  In order to examine the dependence of this frequency on the period, a diffraction experiment by laser scattering was performed (FIG. 3). A laser (wavelength: 672 nm, InGaAlP, spot diameter: about 400 μm, manufactured by Sigma Koki Co., Ltd.) was incident perpendicularly to the film surface, and a diffraction spot was projected onto the screen. The period and periodicity were determined from the projected spot interval and its diffraction order. Six diffraction images were taken for each measurement condition, and the pore diameter and periodicity were averaged.

  FIG. 4 shows the relationship between the diffraction order of laser diffraction and the vibration frequency when solutions of 5 g / L and 10 g / L are used. From these graphs, it was shown that in both cases, when vibration with a frequency of 50 Hz was applied, the order of diffraction was high and high periodicity was exhibited. Also, when the amplitude is large (43V), medium (25-30V), and small (15V) due to the difference in voltage applied to the piezo element, the effect becomes more prominent by increasing the vibration amplitude. . From this result, it has been clarified that the periodicity of the honeycomb film is improved by the influence of vibration.

 As is clear from the above examples, when manufacturing a honeycomb film, a simple means of attaching a vibrator to the film generation substrate and controlling the vibration is significantly improved, so that the manufacturing efficiency of the honeycomb film is remarkably increased. It was revealed that it was improved. In particular, by combining with the pair of substrate apparatuses shown in FIG. 1 above, it becomes possible to continuously manufacture a honeycomb film, a manufacturing bottleneck is solved at once, and manufacturing efficiency is remarkably improved. From the above points, the significance of the present invention is considered to be exceptional.

  According to the present invention, it has been clarified that by applying a simple means of applying vibrations, the pores of the honeycomb fill can be obtained in a very uniform and regular arrangement, which is highly reproducible. The significance of providing a high-efficiency manufacturing process for high-quality honeycomb fill is extremely significant. In view of the situation where the use situation of this kind of porous fill is gradually increasing, it is expected that the high-quality honeycomb film according to the present invention will be developed and expanded mainly in the future and will be used greatly. Expected.

The conceptual diagram of the apparatus which manufactures the honeycomb film of this invention. The figure which shows the SEM image of the high quality honeycomb film produced in the Example of this invention. Diagram showing quality evaluation method of honeycomb film by laser scattering The figure which shows the relationship between vibration frequency and the periodicity of the hole of the honeycomb film

Claims (9)

A hydrophobic organic solvent solution in which a mixture of a functional polymer and an amphiphilic polymer is dissolved is cast on a substrate in an atmosphere having a relative humidity of 50 to 95%, and the organic solvent is gradually evaporated, and at the same time, the cast In a method of manufacturing a honeycomb film in which moisture is condensed on the liquid surface and minute water droplets generated by the condensation are evaporated to form honeycomb-shaped pores using the water droplets as a template, vibration is applied to the solution cast on the substrate. A method for manufacturing a honeycomb film, characterized in that a honeycomb film is produced while being applied. The method for manufacturing a honeycomb film according to claim 1, wherein the frequency to be applied is appropriately adjusted in a range of 1 Hz to 500 Hz. The substrate on which the solution is cast is composed of a pair of substrates placed in parallel with a gap. The solution is cast into the gap to be brought into contact with both substrates, and one of them is parallel while maintaining the contact state. The method for manufacturing a honeycomb film according to claim 1, wherein the film is formed by being moved to a film. A nozzle that blows high-humidity air at a casting position is set, and high-humidity air is blown against a cast raw material solution and a film to be generated, so that water droplets are condensed on the film surface. 4. The method for manufacturing a honeycomb film according to any one of 1 to 3. The means for applying vibration to the cast solution and the substrate is a piezo vibrator, and by controlling the vibrator, the size and arrangement of water droplets are controlled, and the size and arrangement of the holes in the honeycomb film are controlled. A method for manufacturing a honeycomb film according to any one of claims 1 to 4. The method for manufacturing a honeycomb structure according to any one of claims 1 to 5, wherein the functional polymer is one selected from biodegradable, photofunctional, and electronic functional materials. . The method for manufacturing a honeycomb structure according to any one of claims 1 to 6, wherein a pore diameter of the honeycomb structure is 0.1 to 50 µm. In a honeycomb film manufacturing apparatus that uses condensed water droplets as a template, a piezo vibrator is brought into contact with a substrate on which a film is generated, and the substrate is developed on the substrate and the film formed on the substrate and the water droplets that are condensed on the film are microscopic. It gives vibrations and eliminates the formation of abnormal particles in the micro water droplets that are condensed on the film, and also gives regularity and periodicity to the arrangement of the micro water droplets, and thereby regularity and periodicity are formed in the honeycomb-like pores formed in the film. An apparatus for manufacturing a honeycomb film, characterized in that the property is imparted. 9. The apparatus for manufacturing a honeycomb film according to claim 8, wherein the film generation substrate includes two parallel substrates that are installed with a gap and are relatively movable.

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