WO2011114998A1 - Transparent thin film of transition metal oxide having a large diameter nano-spaces, method for producing same and dye-sensitized device electrode - Google Patents

Transparent thin film of transition metal oxide having a large diameter nano-spaces, method for producing same and dye-sensitized device electrode Download PDF

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WO2011114998A1
WO2011114998A1 PCT/JP2011/055705 JP2011055705W WO2011114998A1 WO 2011114998 A1 WO2011114998 A1 WO 2011114998A1 JP 2011055705 W JP2011055705 W JP 2011055705W WO 2011114998 A1 WO2011114998 A1 WO 2011114998A1
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thin film
nanospace
transparent thin
transition metal
large pore
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French (fr)
Japanese (ja)
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木村　辰雄
デブラージ チャンドラ
加藤　一実
大司　達樹
修司 曾根▲崎▼
允 戸次
雅子 中村
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独立行政法人産業技術総合研究所
Toto株式会社
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    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G23/00—Compounds of titanium
    • C01G23/04—Oxides; Hydroxides
    • C01G23/047—Titanium dioxide
    • C01G23/053—Producing by wet processes, e.g. hydrolysing titanium salts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/0203—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of metals not provided for in B01J20/04
    • B01J20/0211—Compounds of Ti, Zr, Hf
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/0203—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of metals not provided for in B01J20/04
    • B01J20/024—Compounds of Zn, Cd, Hg
    • B01J20/0244—Compounds of Zn
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/0203—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising compounds of metals not provided for in B01J20/04
    • B01J20/0251—Compounds of Si, Ge, Sn, Pb
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/02—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material
    • B01J20/06—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof comprising inorganic material comprising oxides or hydroxides of metals not provided for in group B01J20/04
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/28—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties
    • B01J20/28054—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof characterised by their form or physical properties characterised by their surface properties or porosity
    • B01J20/28078—Pore diameter
    • B01J20/2808—Pore diameter being less than 2 nm, i.e. micropores or nanopores
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J20/00—Solid sorbent compositions or filter aid compositions; Sorbents for chromatography; Processes for preparing, regenerating or reactivating thereof
    • B01J20/30—Processes for preparing, regenerating, or reactivating
    • B01J20/305—Addition of material, later completely removed, e.g. as result of heat treatment, leaching or washing, e.g. for forming pores
    • B01J20/3064—Addition of pore forming agents, e.g. pore inducing or porogenic agents
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G19/00—Compounds of tin
    • C01G19/02—Oxides
    • C—CHEMISTRY; METALLURGY
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    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G9/00—Compounds of zinc
    • C01G9/02—Oxides; Hydroxides
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K30/00—Organic devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation
    • H10K30/80—Constructional details
    • H10K30/81—Electrodes
    • H10K30/82—Transparent electrodes, e.g. indium tin oxide [ITO] electrodes

Definitions

  • the present invention relates to a transparent thin film having a large amount of large pore nanospaces of titanium oxide, tin oxide and zinc oxide prepared in the presence of a surfactant, and a method for producing the same, and includes a transition metal oxide surface and biologically relevant molecules.
  • a transparent thin film of transition metal oxide having a pore size nanospace As an electrode material that enables high-sensitivity sensing of dye-sensitized devices that use biologically relevant molecules immobilized on the surface of transition metal oxides
  • the present invention relates to a transparent thin film of transition metal oxide having a pore size nanospace.
  • the mesoporous material synthesized by utilizing the property that the amphiphilic organic compound self-assembles in the solution is expected to develop various applications depending on the composition constituting the skeleton.
  • centering on silica-based materials while using organic modification etc. in parallel with research and development on pore size control, morphology control, introduction of foreign elements into the skeleton, functionalization in mesopores, etc.
  • Use in adsorption separation involving relatively large organic molecules such as pharmaceuticals, drug delivery systems (DDS), catalytic reactions, and the like has been studied.
  • the control range of the pore diameter of the mesoporous material by the silica-based material is not wide, and the present situation is not yet satisfactory with respect to the above utilization.
  • n PO m EO polyoxyethylene-polyoxypropylene-polyoxyethylene
  • n , n and m are the number of polymerization of each unit) synthesized using a triblock copolymer, and the control range of the pore diameter is not wide.
  • pore diameter is generally in the range of 10 nm or less, and therefore the size of protein or DNA is 10 nm. Therefore, it cannot be used for selectively handling biologically related molecules exceeding the above range, and therefore further increase in pore size is desired.
  • Non-Patent Document 1 a method of obtaining a macroporous body (reverse opal structure) having a large pore nanospace of an inorganic oxide by transferring a regular laminated structure (opal structure) of spherical particles such as polystyrene (hereinafter abbreviated as PS).
  • PS polystyrene
  • the rate of lamination (sedimentation) of small PS spherical particles is slower than the volatilization rate of the dispersion solvent, it is difficult to precisely laminate the PS spherical particles, and the spherical particles are laminated and the inorganic precursor solution is immersed.
  • Another disadvantage of this process is that it requires a multi-step synthesis process such as drying of the dispersion solvent. For example, when a thin film is formed, if the film is formed by spin coating, the volatilization rate of the solvent is high, so the thin film is formed before the spherical particles are stacked, and the spherical PS particles are introduced into the thin film in an isolated state. It may be done.
  • PS n -b-PEO m polystyrene-polyoxyethylene diblock copolymer
  • a feature of the synthesis using PS n -b-PEO m is that spherical mesopores are likely to be generated. Even if the diameter of the generated mesopores corresponds to the size of the bio-related molecule, Since the entire inside of the thin film cannot be used effectively unless the bio-related molecules can pass through the connecting holes between the mesopores, handling can be performed by simply relating the diameter of the generated mesopores directly to the size of the bio-related molecules. It doesn't matter.
  • spherical mesopores with a pore diameter of 10 nm are connected by pores of less than 1 nm and exist in an almost isolated state (non-patented) Reference 2).
  • mesoporous carbon synthesized using PS 230 -b-PEO 125 spherical mesopores are generated and the maximum pore diameter is 26 nm, but there are about 5 nm connecting pores.
  • Non-patent Document 4 The pore diameter of mesoporous platinum synthesized using PS 35 -b-PEO 109 is only 15 nm, and in this case, the pores are merely connected by small pores.
  • a crater-like space exists in the entire thin film, and it is not a porous thin film.
  • the diameter of the crater-like space that can be calculated from the description is not so large as about 30 nm (Non-Patent Document 5). Therefore, regarding the synthesis using PS n -b-PEO m , the synthesis of a thin film having a porous structure capable of diffusing biomolecules throughout the thin film has not been realized.
  • the present invention has been made in view of the circumstances as described above, and has a large pore diameter in the range of 30 to 150 nm so that biologically relevant molecules and the like can be handled selectively and in large quantities.
  • the present inventor used an extremely large polymerization number and synthesized an inorganic raw material optimally when synthesizing a semiconductor oxide thin film in the presence of PS n -b-PEO m. As a result, it was found that the intended purpose can be achieved, and the present invention has been completed.
  • a polyoxyethylene unit that plays a hydrophilic role (hereinafter abbreviated as a PEO unit) and a polystyrene unit that plays a hydrophobic role within a range of 300 to 4000 (hereinafter abbreviated as a PS unit) )
  • a transition metal oxide precursor made of one or more of a metal salt of titanium, tin or zinc and a metal alkoxide as a raw material A method for producing a transparent thin film of a transition metal oxide having a large pore nanospace, wherein the surfactant is removed.
  • the structure of the transparent thin film is regular or irregular defined by self-assembly of the surfactant. It is a set of spherical spaces.
  • the diameter of the large pore nanospace defined by the self-assembly of the surfactant is in the range of 30 to 150 nm. It is.
  • the large pore size nanospaces are connected by pores larger than 10 nm.
  • the main component of the transparent thin film is titanium oxide, tin oxide or zinc oxide, It has a crystalline structure, a crystal structure or an intermediate phase thereof.
  • the transparent thin film is crystallized in the process of removing the surfactant at a high temperature.
  • a transparent thin film produced by the above first to sixth methods characterized in that spherical large pore nanospaces defined by self-assembly of surfactants are regularly or irregularly assembled. It is the transparent thin film of the transition metal oxide which has large-pore-diameter nanospace.
  • the diameter of the spherical large pore nanospace defined by the self-assembly of the surfactant is 30 to 150 nm.
  • the spherical large pore nanospace defined by the self-assembly of the surfactant is a pore having a diameter larger than 10 nm. It is connected by.
  • the transparent thin film of transition metal oxide having a large pore nanospace is one or more selected from amorphous titanium oxide, tin oxide or zinc oxide It is composed of
  • a biologically related molecule adsorption / separation material comprising a transparent thin film of a transition metal oxide having a large pore nanospace according to any one of the seventh to tenth aspects.
  • Twelfth Dye sensitization characterized by immobilizing functional dye molecules in the large pore size nanospace of the transparent metal oxide transparent thin film having the large pore size nanospace according to any one of the seventh to tenth aspects Type device electrode.
  • the kind of the transition metal oxide in the presence of PS n -b-PEO m having a very large number of polymerizations which defines the number of polymerizations of the block copolymer of PS units. It is possible to form a transition metal oxide having a large pore nanospace whose diameter exceeds 100 nm by preparing a transparent precursor solution with a prescribed thickness, and to reduce the wall thickness around the large pore nanospace Thus, the connecting holes can be generated and increased.
  • a transparent thin film of transition metal oxide having a large pore nanospace can be realized by the methods of the first to sixth inventions.
  • the transition metal oxide transparent thin film having a large pore nanospace can immobilize a large amount of biologically relevant molecules, and thus can be used as an adsorptive separation material.
  • biologically relevant molecules labeled with dye molecules they can be used as electrode members for dye-sensitized solar cells and electrode members for high-sensitivity sensors for harmful chemical substances using the principle of dye sensitization.
  • FIG. 2 is a graph of powder X-ray diffraction (hereinafter abbreviated as XRD) of a powder sample obtained by drying a transparent precursor solution used when synthesizing a transparent thin film of titanium oxide having a large pore nanospace of Example 1.
  • FIG. is there. 4 is a SEM photograph of a tin oxide transparent thin film having a large pore nanospace of Example 2.
  • FIG. 3 is an XRD graph of a tin oxide transparent thin film having a large pore nanospace of Example 2.
  • (A) is a graph showing the adsorption behavior of cytochrome c on the surface of a transparent thin film of titanium oxide having a large pore nanospace, which was formed at a spin coating speed of 3000 rpm and fired at 400 ° C. in Example 4
  • (B) is a graph showing the desorption behavior.
  • 6 is a graph showing changes in the amount of cytochrome c adsorbed on the surface of a transparent thin film of titanium oxide having large pore nanospaces synthesized at different firing temperatures in Example 4.
  • FIG. 4 is a comparison of the amount of cytochrome c adsorbed on the surface of a porous thin film of various titanium oxides of Example 4.
  • FIG. 6 is a graph showing a comparison of the amount of Cy5-ssDNA adsorbed on the surface of a porous thin film of various titanium oxides of Example 5.
  • FIG. 7 is a graph showing a comparison between photocurrent generated when Cy5-ssDNA immobilized on the surface of a titanium oxide thin film having a large pore nanospace in Example 5 is excited with 120 mW light and various porous thin films of titanium oxide. is there.
  • FIG. 6 is a graph showing a comparison between photocurrent generated when Cy5-ssDNA immobilized on the surface of a titanium oxide thin film having a large pore nanospace of Example 5 is excited with 6 mW light and various porous thin films of titanium oxide. is there.
  • 6 is a graph showing the adsorption of Cy5-XG69 on the surface of a titanium oxide thin film having a large pore diameter nanospace baked at 400 ° C. in Example 6.
  • FIG. 6 is a graph showing a comparison between photocurrent generated when Cy5-XG69 immobilized on the surface of a titanium oxide thin film having a large pore nanospace in Example 6 is excited with 120 mW light and various porous thin films of titanium oxide. is there.
  • metal raw material of the transition metal oxide used in the present invention one or more selected from a metal salt of titanium, tin or zinc and a metal alkoxide can be used.
  • the metal raw material In order to make the metal raw material a transition metal oxide, it can be prepared by a method of adding a metal salt to an ethanol solution, or a method of hydrolyzing a metal alkoxide by adding hydrochloric acid.
  • the metal raw material for example, if hydrogen chloride is generated from chloride during the reaction or the solution is acidified by adding hydrochloric acid, the hydrophilic portion of the surfactant described later is protonated. , Interaction with dissolved inorganic species becomes stronger.
  • metal alkoxide when metal alkoxide is used, it is sufficient to prepare an acidic precursor solution by adding hydrochloric acid at the same time as the purpose of controlling the reaction. There is no problem even if a salt (nitrate, acetate, etc.) is used as a starting material. Even by mixing the chloride and the alkoxide, the formation of an oxide network is promoted, and at the same time, hydrogen chloride is generated to prepare an acidic precursor solution.
  • the surfactant used in the present invention is a block copolymer composed of a PEO unit that plays a hydrophilic role and a PS unit that plays a hydrophobic role.
  • the above surfactant is dissolved in a solvent to prepare a surfactant solution.
  • a solvent capable of completely dissolving PS n -b-PEO m is not easily selected because of its low solubility in various solvents.
  • THF tetrahydrofuran
  • a mixed solvent of THF and ethanol is preferable as the solvent, and a mixed solvent of THF and ethanol.
  • a polar solvent such as dioxane is also excellent in the ability to dissolve PS n -b-PEO m and can be suitably used.
  • PEO units can interact with dissolved inorganic species in solution by hydrogen bonding, and when used in acidic hydrochloric acid, protonated PEO units and dissolved inorganic species are more strongly and electrostatically Even in the process of interaction and surfactant self-assembly, inorganic species can exist stably in the vicinity of the hydrophilic part, and inorganic organic mesostructures can be generated through bond formation between inorganic species. This is preferable because it is possible.
  • the unit exhibiting hydrophobicity is a PS unit
  • the surfactant is used even when a block copolymer having a large molecular weight, that is, a high degree of polymerization is used.
  • a self-assembled structure is formed.
  • many synthesizing mesoporous materials using EO n PO m EO n have been reported from all over the world, but the maximum number of polymerizations per unit is about 100.
  • phase separation occurs, which makes it difficult to use the structure regularity at the nano level. Therefore, not a polyoxypropylene chain but a block copolymer containing a strongly hydrophobic PS unit is required as a structure-directing agent for a compound having a large pore nanospace.
  • a block copolymer composed of units having a large difference between hydrophilicity and hydrophobicity such as PS n -b-PEO m has a strong property of self-assembling spherically in a polar solvent. For this reason, the nanostructure of the transparent thin film of transition metal oxide having a large pore nanospace is assumed to be an aggregate of spherical large pore nanospaces defined by the self-assembly of the surfactant.
  • the size of the spherical aggregates varies due to the difference in the number of associations and molecular weights, and the assembly of nanopores may become irregular.
  • the number of polymerizations of PS n -b-PEO m is important.
  • the density of PS units is 1.06 gcm ⁇ 3 (refer to the density of 100 nm latex spheres), and PS 35 -b-PEO 109
  • a spherical PS portion having a diameter of 10 nm (10 nm for silica) (see Non-Patent Document 2) and PS 230 -b-PEO 125 having a diameter of 20 nm (31 nm for silica) (see Non-Patent Document 2) is generated.
  • the number of polymerization of the PS unit and the pore size are not in a simple proportional relationship, and when PS n -b-PEO m having a large polymerization number is used, it can be interpreted that several molecules are associated. .
  • a porous body having a pore size of about 30 nm is generated by synthesis using PS 230 -b-PEO 125 (see Non-Patent Document 3), at least about 4 PS 230 -b-PEO 125 molecules are present. It can be interpreted as meeting.
  • the PS unit in order to realize generation of the core part of a PS unit having a diameter of 30 nm in one molecule assembly, the PS unit must have a molecular weight of about 100,000 (the number of polymerization is about 960), and several molecules should be associated. If possible, it can be expected that a larger PS unit core will be generated.
  • the number of associations of a surfactant increases with an increase in molecular weight. Therefore, the molecular structure of the surfactant can be defined in consideration of both the number of polymerizations and the association ability, and the diameter actually exceeds 30 nm. In order to obtain a compound having a large pore nanospace, it is necessary to consider both the number of polymerizations and the number of associations of the PS unit at the same time.
  • the number of polymerized PS units is about 300, it is considered that a PS core portion of about 30 nm can be formed when three molecules are associated. Even if the number of polymerizations is increased to about 4000, it is possible to form a spherical aggregate of about 50 nm with one molecule. To form the core part of a 150 nm PS unit, the number of associations should be about 30 molecules.
  • the number of polymerization of PS n -b-PEO m is not so strict as long as the generated core portion can be surrounded.
  • the PEO unit corresponds to a shell portion, and if the amount of transition metal species that interact with the portion to form a skeleton is too large, the large holes that are generated at the corner are isolated. Even when a transparent thin film of a transition metal oxide having a large pore nanospace with a diameter of 30 to 150 nm can be obtained, the size of the linkage is sufficient to selectively handle a large amount of biologically relevant molecules exceeding 10 nm. The holes are not necessarily present.
  • the wall thickness around the large pore size nano space is largely determined by the amount of inorganic raw material supplied, it is related to the number of polymerizations of the PEO unit, so the connection hole is controlled by reducing the wall thickness by controlling that amount. be able to.
  • titanium tetrapropoxide (0.135 g) is added to a mixed solvent in which PS 960 -b-PEO 3400 (0.08 g) is dissolved in THF / ethanol (11.25 mL) at a volume ratio of 4: 1.
  • a precursor solution prepared by mixing hydrolyzed concentrated hydrochloric acid (0.296 mL), PS 960 -b-PEO 3400 (0.08 g) was added at a volume ratio of 4: 1.
  • hydrochloric acid Sex under include a precursor solution prepared from anhydrous zinc acetate (0.087 g) and the like.
  • the amount of inorganic species that can be present in the shell portion can be controlled by interaction, so the wall condition can be achieved by optimizing the synthesis conditions of the polymerization number and the addition amount of the inorganic raw material.
  • the connection hole can be controlled by controlling the thickness.
  • the structure of a transparent thin film of transition metal oxide having a large pore nanospace and the molecular structure of PS n -b-PEO m are largely related to PS n -b-PEO m.
  • various synthesis conditions such as the THF / ethanol ratio, the amount of solvent, the amount of hydrochloric acid, the reaction time, etc. are appropriately adjusted and desired It becomes possible to obtain a transparent thin film.
  • PS n -b-PEO m itself has a strong tendency to assemble into a spherical shape in a solvent, it is extremely important to prepare a transparent precursor solution.
  • the amount of transition metal species relative to PS n -b-PEO m is also important in order to introduce a large pore nanospace into the entire transparent thin film, and this greatly affects the connectivity of the spherical nanospace.
  • an acidic solution obtained by adding chloride to an ethanol solution or a solution obtained by hydrolyzing alkoxide with concentrated hydrochloric acid is separately prepared. Mix with solution.
  • the surfactant is removed to obtain a transparent thin film of transition metal oxide having a large pore nanospace.
  • the substrate is not particularly limited as long as it has a smooth surface and does not interfere with film formation.
  • a substrate such as glass, quartz, silicon, single crystal ITO, graphite, or Teflon (registered trademark) is preferable. Can be used.
  • a coating method for film formation it can be applied by a known method such as spin coating or dip coating. According to these methods, the film thickness can be controlled by appropriately adjusting coating conditions such as spin coating speed and dip coating pulling speed.
  • the surfactant from the formed thin film it can be removed by baking or UV ozone treatment.
  • the transition metal species As a condition for removing the surfactant by firing, for example, it is possible to remove the surfactant even at a low temperature of 250 ° C. In this case, the transition metal species remains in an amorphous structure and a large pore size nanospace is formed. A transparent thin film of a transition metal oxide can be obtained.
  • the crystallization temperature differs depending on the transition metal species, the structure of the large pore nanospace where the transition metal species is crystallized does not collapse even when processed at a higher temperature. A transparent thin film can be obtained.
  • the transition metal oxide thin film containing a large amount of spherical PS n -b-PEO m aggregates has high transparency, in addition to the removal of the surfactant by the above baking, the surfactant is also removed by UV ozone treatment by ultraviolet irradiation. It can be removed.
  • a transparent thin film of transition metal oxide having a large pore nanospace made of titanium oxide, tin oxide or zinc oxide having an amorphous skeleton structure Can be obtained.
  • the surfactant is removed by baking at a temperature higher than the crystallization temperature of each of titanium oxide, tin oxide, or zinc oxide, the crystallization of the skeleton structure proceeds gradually and includes microcrystals (amorphous structure and crystal It becomes possible to obtain a transparent thin film of a transition metal oxide having a large pore nanospace made of titanium oxide, tin oxide or zinc oxide having a unique crystal structure from the intermediate phase of the structure.
  • a large amount of large pore nanospace exists in the range of 30 to 150 nm in the transparent thin film of transition metal oxide, and exceeds 10 nm. Since it has a connecting hole of sufficient size to handle such biologically relevant molecules selectively and in large quantities, it is extremely selective in vivo in proteins and DNA, as represented by enzyme reactions and the like. It can be a specific reaction field for handling functional organic compounds that play an important role in various reactions efficiently.
  • the functional dye molecules can be adsorbed selectively and in large quantities by utilizing the interaction with the surface of the transition metal oxide that constructs the large pore nanospace, the functional dye molecules can be strongly immobilized Can also be separated from the mixture.
  • the transparent thin film of transition metal oxide having a large pore nanospace of the present invention can also be used as an electrode material.
  • Non-Patent Document 6 In research on Gratzel type dye-sensitized solar cells (see Non-Patent Document 6), various combinations of transition metal oxides such as titanium oxide, tin oxide, zinc oxide, and tungsten oxide with dyes have been studied. None has been found that shows conversion efficiency exceeding the combination of titanium and ruthenium complex. For example, it has been reported that a conversion efficiency of 10% is realized by a combination of titanium oxide nanocrystal particles and a ruthenium complex (see Non-Patent Documents 7 to 9). This describes that the titanium oxide electrode is designed with nanoparticles in order to increase the amount of dye molecules (ruthenium complex) adsorbed.
  • the transition metal oxide transparent thin film having a large pore nanospace according to the present invention is not only an extremely useful electrode material, but also can greatly increase the amount of dye molecules adsorbed, and also has a very high thin film transparency. An efficient conversion can be expected.
  • the transparent thin film of transition metal oxide having a large pore nanospace of the present invention can be effectively used as an electrode material for a dye-sensitized solar cell.
  • transition metal oxide transparent thin film having a large pore nanospace of the present invention can be used as an electrode material for the construction of a sensor system using the principle of dye sensitization.
  • a dye-sensitized device is constructed using a labeling dye in order to highly sensitively detect environmental hormones that are highly toxic even in very small amounts. It is extremely important for high sensitivity to adsorb chemical substances (dioxins, estradiol, bisphenol A, etc.) suspected as environmental hormones on the surface of the semiconductor electrode as much as possible and selectively.
  • a dye-sensitized solar cell sunlight can be used on the principle that energy is transferred from a photoexcited dye to a semiconductor electrode to generate a current.
  • fluorescence or electrons (photocurrent) generated from the photoexcited labeling dye are detected using a fluorescence spectrum measurement or an ammeter, respectively.
  • dioxins interact with DNA molecules very selectively. Since the labeling dye is denatured simultaneously with the adsorption, dioxins can be sensed with high sensitivity by detecting fluorescence or photocurrent from the denatured dye.
  • the DNA at this time is called a dioxin receptor. If the estradiol receptor is immobilized on the electrode surface, estradiol can be sensed with high sensitivity.
  • a large amount of DNA molecules can be immobilized even on a transparent electrode having a large pore nanospace such as titanium oxide, tin oxide and zinc oxide.
  • PS n -b-PEO m having a PS unit number average molecular weight of 100,000 (polymerization number of about 960) and a PEO unit number average molecular weight of 150,000 (polymerization number of about 3400) (PS 960 -b -PEO 3400 ) was used to synthesize a transparent thin film of titanium oxide having a large pore nanospace.
  • PS 960 -b-PEO 3400 (0.08 g) was completely dissolved in a mixed solvent of THF / ethanol (11.25 mL) at a volume ratio of 4: 1.
  • a concentrated solution (0.296 mL) is slowly added dropwise to titanium tetrapropoxide (0.135 g) to prepare a transparent hydrolyzed solution, which is then mixed with a surfactant solution to prepare a transparent precursor solution.
  • the thin film was obtained by spin-coating the obtained solution on a glass substrate. Immediately after the film formation, the thin film was cooled to ⁇ 20 ° C. to slow down the formation of the titanium oxide skeleton network, and proceeded to a drying operation at 50 ° C. before frost was formed inside the thin film by moisture in the air.
  • the surfactant was removed by baking at 400 ° C. to obtain a transparent thin film of titanium oxide having a large pore nanospace.
  • PS n -b-PEO m having a small number of polymerizations, it was possible to obtain a transparent thin film of titanium oxide having a nanospace with an arbitrarily smaller diameter.
  • the powder sample obtained by drying the transparent precursor solution in a tray was fired at 250 ° C. and 400 ° C., and the relationship between the crystallinity of the titanium oxide skeleton and the firing temperature was measured by XRD. The result is shown in FIG. The presence of diffraction peaks that can be attributed to the anatase phase of titanium oxide was confirmed in most cases when it was fired at 250 ° C., and when it was fired at 400 ° C.
  • the crystallinity of the skeleton of the transition metal oxide having a large pore nanospace can be controlled by the firing temperature. Further, when the thin film was shaved and observed with a transmission electron microscope at a high magnification, it was observed that a large amount of anatase crystals of about 5 to 10 nm were present inside the skeleton of the thin film fired at 400 ° C. As a result of film formation at a spin coating speed of 800 to 3000 rpm, the film thickness after baking at 250 ° C. or 400 ° C. was about 200 nm. As a result of evaluating the porosity of the thin film by krypton (Kr) gas adsorption measurement, the specific surface area was about 30 m 2 cm ⁇ 3 .
  • a transparent thin film of tin oxide having a large pore nanospace was synthesized using PS 960 -b-PEO 3400 .
  • PS 960 -b-PEO 3400 (0.08 g) was completely dissolved in a THF / ethanol (10 g) mixed solvent having a volume ratio of 4: 1.
  • pure water 0.2 mL was added to a solution obtained by hydrolyzing in advance by adding concentrated hydrochloric acid (0.296 mL) dropwise to anhydrous tin dichloride (0.06 g), and PS 960- b-PEO 3400
  • a clear precursor solution was prepared by mixing with the solution.
  • the thin film was obtained by spin-coating the obtained solution on a glass substrate. Immediately after the film formation, the thin film was cooled to ⁇ 20 ° C., dried at 50 ° C. and then fired at 450 ° C. to remove the surfactant.
  • the large pore nanospace of the obtained thin film exists in the entire thin film, the diameter of the nanospace can be estimated to be 10 to 150 nm, and the large pore nanospace is larger than 10 nm. It was confirmed that the holes were connected by holes. It was confirmed that the large pore nanospace was surrounded by the tin oxide nanocrystals, and as a result of direct XRD measurement of the transparent thin film, it was confirmed that the tin oxide skeleton was sufficiently crystallized. The result of the XRD measurement is shown in FIG.
  • a transparent thin film of zinc oxide having a large pore nanospace was synthesized using PS 960 -b-PEO 3400 .
  • PS 960 -b-PEO 3400 (0.08 g) was completely dissolved in a THF / ethanol (11.76 mL) mixed solvent having a volume ratio of 4: 1.
  • a transparent precursor solution was prepared by mixing a transparent solution prepared from anhydrous zinc acetate (0.087 g) with a surfactant solution under acidic conditions of hydrochloric acid.
  • a film was formed by spin-coating the obtained solution on a glass substrate, completely dried, and then baked at 400 ° C. to remove the surfactant and crystallize the zinc oxide skeleton.
  • Cy-c cytochrome c
  • UV-Vis ultraviolet-visible spectroscopy
  • FIG. 5 (a) shows the desorption behavior in FIG. 5 (b).
  • FIG. 6 shows changes in the amount of Cy-c adsorbed on the surface of a transparent thin film of titanium oxide having a large pore nanospace synthesized at different firing temperatures of 250 to 600 ° C. From this XRD measurement, it was confirmed that when the firing temperature was increased, an anatase phase was generated and the crystallinity was improved. Increasing the calcination temperature increased the amount of Cy-c adsorbed, although the specific surface area hardly changed. Therefore, it can be seen that the crystallinity of the titanium oxide skeleton also affects the amount of Cy-c adsorption.
  • the transparent thin film of titanium oxide having large pore nanospaces of the present invention which is composed of macropores and a large number of large connecting pores, has excellent adsorption characteristics for relatively large molecules such as Cy-c. It can be interpreted as shown.
  • a transparent thin film of transition metal oxide having a large pore nanospace by the transparent precursor solution prepared in Example 1 was formed on a fluorine-doped tin oxide (FTO) substrate, and a DNA adsorption experiment was performed.
  • FTO fluorine-doped tin oxide
  • One molecule of dye (cytochrome) was labeled with respect to one DNA molecule, and the amount of adsorbed DNA was calculated from intensity measurement of fluorescence emission from the labeled dye.
  • the molecule is expressed as Cy5-ssDNA (base sequence: GCGGCATGAACCTGAGGCCCCATCCT).
  • porphyrin ring structure with a metal center of iron (Fe), which functions as an electron transfer protein in vivo, but the porphyrin ring structure is used as a dye molecule for capturing light energy.
  • Fe metal center of iron
  • ssDNA dissolved in water was denatured by heating at 95 ° C. for 10 minutes, and 5 mL was spot-dropped on the thin film and held at 95 ° C. for 10 minutes.
  • the thin film was washed with 0.2% sodium dodecyl sulfate aqueous solution, rinsed with pure water, immersed in boiling water for 2 minutes, and then immersed in ethanol at 4 ° C. for 2 minutes to remove excess biomolecules.
  • Cy-c strongly interacts with the surface of titanium oxide and tin oxide from the behavior of adsorption from aqueous solution and desorption into water. Showed that.
  • Cy5-ssDNA was immobilized on the thin film surface, and then the substrate was thoroughly washed to remove excess biomolecules. Nevertheless, Cy5-ssDNA was immobilized on the thin film surface. Therefore, it was confirmed that it was extremely strongly immobilized.
  • Cy5-ssDNA was adsorbed on the surface of the tin oxide thin film having a large pore nanospace that was baked at 450 ° C. to crystallize the skeleton.
  • the amount of Cy5-ssDNA adsorbed was an order of magnitude less than that of a titanium oxide thin film having a large pore nanospace that was baked at 400 ° C. to crystallize the skeleton.
  • the current value was saturated.
  • 6 mW There was a good relationship between the photocurrent and the amount of dye adsorbed when the light source was very weak, 6 mW, indicating a larger current value than the titanium oxide thin film.
  • a transparent thin film of a transition metal oxide having a large pore nanospace with the transparent precursor solution prepared in Example 1 was formed on an FTO substrate, and proteins (Anti-AFP antibody NB0-13, AFP: alpha-feto-protein) , Japan Biotest) adsorption experiment.
  • a molecule in which one molecule of dye (Cy5) was labeled with respect to NB0-131 molecule was expressed as Cy5-NB0-13, and the amount of protein adsorbed was calculated from the measurement of the intensity of fluorescence emitted from the labeled dye. It was also confirmed whether photocurrent generated from adsorbed Cy5 was detected.
  • the protein was detected using the antigen-antibody reaction.
  • PSA Prostate Specific Antigen
  • XG-69 goat: Fitzgerald Industries International, Inc.
  • the secondary antibody was a protein (Anti-PSA monoclonal antibody: 5A6, neutral: 5A6-mouseGoneBoth )
  • 5A61 5A61 molecule
  • the photocurrent measurement result also shows a good correlation with the fluorescence value, and in the case of a tin oxide thin film, photocurrent detection using the principle of a dye-sensitized solar cell is possible. there were.

Abstract

Disclosed is a method for producing a transparent thin film of a transition metal oxide wherein large pores with a diameter in the range of 30 - 150 nm that can handle biologically relevant molecules selectively and in large volumes are present, and the connecting pores therefor are of a size that biologically relevant molecules can pass through. This method is characterized in that, after mixing of a surface active agent, which is constituted by block copolymerization of a polyoxyethylene unit that plays a hydrophilic role and a polystyrene unit with a degree of polymerization in the range of 300 - 4000 that plays a hydrophobic role, a metal salt of titanium, tin or zinc and a precursor transition metal oxide having one or more metal alkoxides as an inorganic starting material and after film growth, the surface active agent is eliminated. Also disclosed is the transparent thin film.

Description

大孔径ナノ空間を有する遷移金属酸化物の透明薄膜、その製造方法及び色素増感型デバイス電極Transparent thin film of transition metal oxide having large pore nanospace, method for producing the same, and dye-sensitized device electrode
　本発明は、界面活性剤存在下で調製した酸化チタン、酸化スズ及び酸化亜鉛の大孔径ナノ空間を大量に有する透明薄膜及びその製造方法に関するものであり、遷移金属酸化物の表面と生体関連分子との相互作用から誘導される吸着分離材として、また、遷移金属酸化物の表面に固定化した生体関連分子を利用する色素増感型デバイスの高感度センシングを可能とする電極部材としての、大孔径ナノ空間を有する遷移金属酸化物の透明薄膜に関するものである。 The present invention relates to a transparent thin film having a large amount of large pore nanospaces of titanium oxide, tin oxide and zinc oxide prepared in the presence of a surfactant, and a method for producing the same, and includes a transition metal oxide surface and biologically relevant molecules. As an electrode material that enables high-sensitivity sensing of dye-sensitized devices that use biologically relevant molecules immobilized on the surface of transition metal oxides The present invention relates to a transparent thin film of transition metal oxide having a pore size nanospace.
　両親媒有機化合物が溶液中で自己集合する性質を利用して合成されるメソ多孔体は、骨格を構成する組成に応じて様々な応用展開が期待される。その中でも、シリカ系材料を中心に、孔径の制御、形態の制御、骨格内への異種元素の導入、メソ孔内の機能化等に関する研究開発と並行して、有機修飾等も利用しながら、医薬品等の比較的大きな有機分子の関与する吸着分離や、ドラッグデリバリーシステム（ＤＤＳ）、触媒反応等への利用が検討されている。しかしながら、シリカ系材料によるメソ多孔体の孔径の制御範囲は広いものではなく、上記の利用に関しては未だ満足できるものとはなっていないのが現状である。 The mesoporous material synthesized by utilizing the property that the amphiphilic organic compound self-assembles in the solution is expected to develop various applications depending on the composition constituting the skeleton. Among them, centering on silica-based materials, while using organic modification etc. in parallel with research and development on pore size control, morphology control, introduction of foreign elements into the skeleton, functionalization in mesopores, etc. Use in adsorption separation involving relatively large organic molecules such as pharmaceuticals, drug delivery systems (DDS), catalytic reactions, and the like has been studied. However, the control range of the pore diameter of the mesoporous material by the silica-based material is not wide, and the present situation is not yet satisfactory with respect to the above utilization.
　また、非シリカ系材料に関しても、有機分子集合体を利用した多様なメソ多孔体の合成が報告されているが、そのほとんどがポリオキシエチレン－ポリオキシプロピレン－ポリオキシエチレン（ＥＯｎＰＯｍＥＯｎ、ｎ、ｍは各ユニットの重合数）系トリブロック共重合体を利用して合成されたものであり、孔径の制御範囲は広いものではない。 As for non-silica materials, synthesis of various mesoporous materials using organic molecular aggregates has been reported. Most of them are polyoxyethylene-polyoxypropylene-polyoxyethylene (EO n PO m EO). n , n and m are the number of polymerization of each unit) synthesized using a triblock copolymer, and the control range of the pore diameter is not wide.
　また、酸化チタン、酸化スズ、酸化亜鉛等の半導体酸化物のメソ多孔体合成も数多く提案されているが、孔径は概ね１０ｎｍ以下の範囲であり、従って、タンパク質やＤＮＡのような大きさが１０ｎｍを超えるような生体関連分子等を選択的にハンドリングすることには利用できず、そのため更なる孔径の増大が望まれている。 In addition, many mesoporous materials are synthesized for semiconductor oxides such as titanium oxide, tin oxide, and zinc oxide. However, the pore diameter is generally in the range of 10 nm or less, and therefore the size of protein or DNA is 10 nm. Therefore, it cannot be used for selectively handling biologically related molecules exceeding the above range, and therefore further increase in pore size is desired.
　さらに、ポリスチレン（以下、ＰＳと略称する）等の球状粒子の規則的な積層構造（オパール構造）を転写して無機酸化物の大孔径ナノ空間を有するマクロ多孔体（逆オパール構造）を得る方法が提案されている（非特許文献１）。この場合には２００ｎｍを超えるような大きな直径の球状細孔の形成は比較的多く提案されているが、それより小さな直径の多孔体薄膜の合成は知られていない。分散溶媒の揮発速度に比べて、小さなＰＳ球状粒子の積層（沈降）速度が遅いために、ＰＳ球状粒子を精密に積層することが困難であり、また、球状粒子の積層、無機前駆溶液の浸漬、分散溶媒の乾燥等多段階の合成プロセスが必要となる点もこのプロセスの短所である。例えば、薄膜の形成を行う場合にスピンコート法で成膜すると溶媒の揮発速度が速いために球状粒子が積層する前に薄膜が形成してしまい、球状ＰＳ粒子が孤立した状態で薄膜内部に導入されてしまう場合がある。 Furthermore, a method of obtaining a macroporous body (reverse opal structure) having a large pore nanospace of an inorganic oxide by transferring a regular laminated structure (opal structure) of spherical particles such as polystyrene (hereinafter abbreviated as PS). Has been proposed (Non-Patent Document 1). In this case, formation of spherical pores having a large diameter exceeding 200 nm has been proposed, but synthesis of a porous thin film having a smaller diameter is not known. Since the rate of lamination (sedimentation) of small PS spherical particles is slower than the volatilization rate of the dispersion solvent, it is difficult to precisely laminate the PS spherical particles, and the spherical particles are laminated and the inorganic precursor solution is immersed. Another disadvantage of this process is that it requires a multi-step synthesis process such as drying of the dispersion solvent. For example, when a thin film is formed, if the film is formed by spin coating, the volatilization rate of the solvent is high, so the thin film is formed before the spherical particles are stacked, and the spherical PS particles are introduced into the thin film in an isolated state. It may be done.
　これらの状況に対し、ポリスチレン－ポリオキシエチレンジブロック共重合体（以下、ＰＳｎ－ｂ－ＰＥＯｍと略称する）（ｎ、ｍは各ユニットの重合数）を用いた合成により、幾つかの大孔径メソ多孔体の合成が報告されているが、これらにおいても孔径の増大は不十分である。 In response to these situations, synthesis using a polystyrene-polyoxyethylene diblock copolymer (hereinafter abbreviated as PS n -b-PEO m ) (where n and m are the number of polymerization of each unit) Although the synthesis of large pore mesoporous materials has been reported, the increase in pore size is insufficient even in these.
　ＰＳｎ－ｂ－ＰＥＯｍを用いた合成の特徴は球状メソ孔が生成しやすい点にあるが、生成したメソ孔の直径が生体関連分子のサイズに対応したものであったとしても、球状のメソ孔間の連結孔を生体関連分子が通過できなければ薄膜内部全体を有効に利用できないことから、単純に生成したメソ孔の直径をそのまま生体関連分子のサイズと関係付けてハンドリングが可能となることにはならない。 A feature of the synthesis using PS n -b-PEO m is that spherical mesopores are likely to be generated. Even if the diameter of the generated mesopores corresponds to the size of the bio-related molecule, Since the entire inside of the thin film cannot be used effectively unless the bio-related molecules can pass through the connecting holes between the mesopores, handling can be performed by simply relating the diameter of the generated mesopores directly to the size of the bio-related molecules. It doesn't matter.
　例えば、ＰＳ３５－ｂ－ＰＥＯ１０９を用いてメソポーラスシリカを合成した場合、孔径１０ｎｍの球状メソ孔が１ｎｍにも満たない孔で連結されており、ほぼ孤立した状態で存在している（非特許文献２）。また、ＰＳ２３０－ｂ－ＰＥＯ１２５を用いて合成したメソポーラスカーボンにおいても球状メソ孔が生成し、孔径は最大で２６ｎｍであるが、５ｎｍ程度の連結孔が存在しており、シリカの場合には孔径が３１ｎｍ近くのものが得られるが、その球状メソ孔は孤立しており、水熱処理を行うことで漸く孔で連結された状態にできる（非特許文献３）。ＰＳ３５－ｂ－ＰＥＯ１０９を用いて合成したメソポーラス白金の孔径も１５ｎｍにしかなっておらず、この場合も小さな孔で連結されているに過ぎない（非特許文献４）。 For example, in the case of synthesizing mesoporous silica using PS 35 -b-PEO 109 , spherical mesopores with a pore diameter of 10 nm are connected by pores of less than 1 nm and exist in an almost isolated state (non-patented) Reference 2). Also, in mesoporous carbon synthesized using PS 230 -b-PEO 125 , spherical mesopores are generated and the maximum pore diameter is 26 nm, but there are about 5 nm connecting pores. Although the thing with a hole diameter near 31 nm is obtained, the spherical mesopore is isolated and can be made into the state connected with the hole gradually by performing a hydrothermal treatment (nonpatent literature 3). The pore diameter of mesoporous platinum synthesized using PS 35 -b-PEO 109 is only 15 nm, and in this case, the pores are merely connected by small pores (Non-patent Document 4).
　また、酸化チタン薄膜をＰＳ６０－ｂ－ＰＥＯ４５０を用いた合成例では、薄膜全体にクレーター状の空間（凹凸構造）が存在しているだけで、多孔質薄膜になっているわけではない。記載内容から算出できるクレーター状の空間の直径は３０ｎｍ程度とそれほど大きいものではない（非特許文献５）。従って、ＰＳｎ－ｂ－ＰＥＯｍを用いた合成に関しては、生体分子を薄膜全体にまで拡散できるような多孔質構造を有する薄膜の合成は実現されていないのが現状である。 Further, in the synthesis example using the PS 60 -b-PEO 450 for the titanium oxide thin film, a crater-like space (uneven structure) exists in the entire thin film, and it is not a porous thin film. The diameter of the crater-like space that can be calculated from the description is not so large as about 30 nm (Non-Patent Document 5). Therefore, regarding the synthesis using PS n -b-PEO m , the synthesis of a thin film having a porous structure capable of diffusing biomolecules throughout the thin film has not been realized.
　上記のように、ＰＳｎ－ｂ－ＰＥＯｍを利用したことにより、ある程度の孔径の増大は実現されたが、十分とは言えず、更には、連結孔が非常に小さいために、タンパク質やＤＮＡ等の１０ｎｍ以上の大きさの生体関連分子を選択的かつ大量にハンドリングできるような直径が３０～１００ｎｍ、或いはそれ以上の範囲の大孔径を有する無機酸化物の合成はほとんど例がないのが現状である。 As described above, by using PS n -b-PEO m , a certain degree of increase in pore diameter was realized, but it was not sufficient, and furthermore, since the connecting pores were very small, protein and DNA There are few examples of synthesizing inorganic oxides having a large pore diameter in the range of 30 to 100 nm or more so that a biologically relevant molecule having a size of 10 nm or more can be selectively and massively handled. It is.
　本発明は、以上の通りの事情に鑑みてなされたものであり、生体関連分子等を選択的かつ大量にハンドリングできるような、直径が３０～１５０ｎｍの範囲の大孔径が存在し、その連結孔に関しても生体関連分子が通過できるような大きさの遷移金属酸化物の透明薄膜の製造方法及び透明薄膜を提供することを課題とする。 The present invention has been made in view of the circumstances as described above, and has a large pore diameter in the range of 30 to 150 nm so that biologically relevant molecules and the like can be handled selectively and in large quantities. In addition, it is an object of the present invention to provide a method for producing a transparent thin film of a transition metal oxide and a transparent thin film having such a size that biological molecules can pass through.
　本発明者は、鋭意研究を積み重ねた結果、ＰＳｎ－ｂ－ＰＥＯｍの存在下で半導体酸化物薄膜を合成する際に、重合数の極めて大きいものを利用すると同時に、添加する無機原料を最適化することにより所期の目的を達成し得ることを見出し、本発明を完成させるに至った。 As a result of intensive research, the present inventor used an extremely large polymerization number and synthesized an inorganic raw material optimally when synthesizing a semiconductor oxide thin film in the presence of PS n -b-PEO m. As a result, it was found that the intended purpose can be achieved, and the present invention has been completed.
　即ち、本発明によれば上記の課題を解決するために、以下のことを特徴としている。 That is, according to the present invention, in order to solve the above problems, the following features are provided.
　第１：親水的な役割を果たすポリオキシエチレンユニット（以下、ＰＥＯユニットと略称する）と、疎水的な役割を果たす重合数が３００～４０００の範囲内のポリスチレンユニット（以下、ＰＳユニットと略称する）のブロック共重合体から構成される界面活性剤と、チタン、スズ又は亜鉛の金属塩及び金属アルコキシドの一種以上を無機原料とした遷移金属酸化物の前駆体を混合して成膜した後、界面活性剤を除去することを特徴とする大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の製造方法である。 First: a polyoxyethylene unit that plays a hydrophilic role (hereinafter abbreviated as a PEO unit) and a polystyrene unit that plays a hydrophobic role within a range of 300 to 4000 (hereinafter abbreviated as a PS unit) ) And a transition metal oxide precursor made of one or more of a metal salt of titanium, tin or zinc and a metal alkoxide as a raw material, A method for producing a transparent thin film of a transition metal oxide having a large pore nanospace, wherein the surfactant is removed.
　第２：上記第１の発明の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の製造方法において、透明薄膜の構造が、界面活性剤の自己集合によって規定される規則的、又は不規則的な球状空間の集合である。 Second: In the method for producing a transparent thin film of transition metal oxide having a large pore nanospace according to the first aspect of the invention, the structure of the transparent thin film is regular or irregular defined by self-assembly of the surfactant. It is a set of spherical spaces.
　第３：上記第２の発明の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の製造方法において、界面活性剤の自己集合によって規定される大孔径ナノ空間の直径が３０～１５０ｎｍの範囲内である。 Third: In the method for producing a transparent thin film of a transition metal oxide having a large pore nanospace according to the second invention, the diameter of the large pore nanospace defined by the self-assembly of the surfactant is in the range of 30 to 150 nm. It is.
　第４：上記第１から第３の発明の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の製造方法において、大孔径ナノ空間が、１０ｎｍより大きい孔によって連結される。 Fourth: In the method for producing a transparent thin film of transition metal oxide having a large pore size nanospace according to the first to third aspects of the invention, the large pore size nanospaces are connected by pores larger than 10 nm.
　第５：上記第１から第４の発明の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の製造方法において、透明薄膜の主成分が、酸化チタン、酸化スズ又は酸化亜鉛であって、非晶質構造、結晶構造又はその中間相を有する。 Fifth: In the method for producing a transparent thin film of transition metal oxide having a large pore nanospace according to the first to fourth aspects of the invention, the main component of the transparent thin film is titanium oxide, tin oxide or zinc oxide, It has a crystalline structure, a crystal structure or an intermediate phase thereof.
　第６：上記第１から第５の発明の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の製造方法において、透明薄膜を、高温で界面活性剤を除去する過程で結晶化させる。 6: In the method for producing a transparent thin film of transition metal oxide having a large pore nanospace according to the first to fifth inventions, the transparent thin film is crystallized in the process of removing the surfactant at a high temperature.
　第７：上記第１から第６の方法によって製造された透明薄膜であって、界面活性剤の自己集合が規定する球状の大孔径ナノ空間が規則的又は不規則に集合してなることを特徴とする大孔径ナノ空間を有する遷移金属酸化物の透明薄膜である。 Seventh: A transparent thin film produced by the above first to sixth methods, characterized in that spherical large pore nanospaces defined by self-assembly of surfactants are regularly or irregularly assembled. It is the transparent thin film of the transition metal oxide which has large-pore-diameter nanospace.
　第８：上記第７の発明の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜において、界面活性剤の自己集合が規定する球状の大孔径ナノ空間の直径が３０～１５０ｎｍである。 Eighth: In the transparent metal oxide transparent thin film having a large pore nanospace according to the seventh aspect of the invention, the diameter of the spherical large pore nanospace defined by the self-assembly of the surfactant is 30 to 150 nm.
　第９：上記第７又は第８の発明の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜において、界面活性剤の自己集合が規定する球状の大孔径ナノ空間が、直径が１０ｎｍより大きな孔によって連結してなる。 Ninth: In the transparent metal oxide transparent thin film having a large pore nanospace according to the seventh or eighth invention, the spherical large pore nanospace defined by the self-assembly of the surfactant is a pore having a diameter larger than 10 nm. It is connected by.
　第１０：上記第７から第９の発明の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜において、透明薄膜が、非晶質の酸化チタン、酸化スズ又は酸化亜鉛から選択される１種以上から構成されている。 Tenth: In the transparent thin film of transition metal oxide having a large pore nanospace according to the seventh to ninth inventions, the transparent thin film is one or more selected from amorphous titanium oxide, tin oxide or zinc oxide It is composed of
　第１１：上記第７から第１０のいずれかに記載の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜からなることを特徴とする生体関連分子の吸着分離材である。 Eleventh: A biologically related molecule adsorption / separation material comprising a transparent thin film of a transition metal oxide having a large pore nanospace according to any one of the seventh to tenth aspects.
　第１２：上記第７から第１０のいずれかに記載の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の大孔径ナノ空間に機能性色素分子を固定化したことを特徴とする色素増感型デバイス電極である。 Twelfth: Dye sensitization characterized by immobilizing functional dye molecules in the large pore size nanospace of the transparent metal oxide transparent thin film having the large pore size nanospace according to any one of the seventh to tenth aspects Type device electrode.
　上記第１から第６の本発明の方法によれば、ＰＳユニットのブロック共重合体の重合数を規定した重合数の極めて大きいＰＳｎ－ｂ－ＰＥＯｍの存在下で遷移金属酸化物の種類を規定して透明な前駆溶液を調製することにより、直径が１００ｎｍを超えるような大孔径ナノ空間を有する遷移金属酸化物の成膜が可能であり、大孔径ナノ空間周囲の壁厚を薄くすることで連結孔を生成、増大させることができる。 According to the first to sixth methods of the present invention, the kind of the transition metal oxide in the presence of PS n -b-PEO m having a very large number of polymerizations, which defines the number of polymerizations of the block copolymer of PS units. It is possible to form a transition metal oxide having a large pore nanospace whose diameter exceeds 100 nm by preparing a transparent precursor solution with a prescribed thickness, and to reduce the wall thickness around the large pore nanospace Thus, the connecting holes can be generated and increased.
　また、上記第７から第１０の発明によれば、上記第１から第６の発明の方法によって大孔径ナノ空間を有する遷移金属酸化物の透明薄膜を現実のものとすることができる。 Further, according to the seventh to tenth inventions, a transparent thin film of transition metal oxide having a large pore nanospace can be realized by the methods of the first to sixth inventions.
　また、上記１１、１２の発明によれば、大孔径ナノ空間を有する遷移金属酸化物の透明薄膜は、生体関連分子を大量に固定化することができるので、吸着分離材として利用でき、更に、色素分子を標識した生体関連分子を利用することで色素増感太陽電池の電極部材、色素増感の原理を利用した有害化学物質の高感度センサーの電極部材としての利用も可能である。 Further, according to the inventions of the above 11 and 12, the transition metal oxide transparent thin film having a large pore nanospace can immobilize a large amount of biologically relevant molecules, and thus can be used as an adsorptive separation material. By using biologically relevant molecules labeled with dye molecules, they can be used as electrode members for dye-sensitized solar cells and electrode members for high-sensitivity sensors for harmful chemical substances using the principle of dye sensitization.
（ａ）は実施例１の大孔径ナノ空間を有する酸化チタンの透明薄膜の走査型電子顕微鏡（以下、ＳＥＭと略称する）写真であり、（ｂ）は拡大したＳＥＭ写真である。(A) is a scanning electron microscope (hereinafter abbreviated as SEM) photograph of a transparent thin film of titanium oxide having a large pore nanospace of Example 1, and (b) is an enlarged SEM photograph. 実施例１の大孔径ナノ空間を有する酸化チタンの透明薄膜を合成する際に利用した透明前駆溶液を乾燥して得られた粉末試料の粉末Ｘ線回折（以下、ＸＲＤと略称する）のグラフである。FIG. 2 is a graph of powder X-ray diffraction (hereinafter abbreviated as XRD) of a powder sample obtained by drying a transparent precursor solution used when synthesizing a transparent thin film of titanium oxide having a large pore nanospace of Example 1. FIG. is there. 実施例２の大孔径ナノ空間を有する酸化スズの透明薄膜のＳＥＭ写真である。4 is a SEM photograph of a tin oxide transparent thin film having a large pore nanospace of Example 2. FIG. 実施例２の大孔径ナノ空間を有する酸化スズの透明薄膜のＸＲＤのグラフである。3 is an XRD graph of a tin oxide transparent thin film having a large pore nanospace of Example 2. FIG. （ａ）は実施例４のスピンコート速度を３０００ｒｐｍで成膜し、４００℃で焼成した大孔径ナノ空間を有する酸化チタンの透明薄膜の表面へのシトクロムｃの吸着挙動を示したグラフであり、（ｂ）は脱離挙動を示したグラフである。(A) is a graph showing the adsorption behavior of cytochrome c on the surface of a transparent thin film of titanium oxide having a large pore nanospace, which was formed at a spin coating speed of 3000 rpm and fired at 400 ° C. in Example 4, (B) is a graph showing the desorption behavior. 実施例４の異なる焼成温度で合成した大孔径ナノ空間を有する酸化チタンの透明薄膜の表面へのシトクロムｃの吸着量の変化を示したグラフである。6 is a graph showing changes in the amount of cytochrome c adsorbed on the surface of a transparent thin film of titanium oxide having large pore nanospaces synthesized at different firing temperatures in Example 4. FIG. 実施例４の各種酸化チタンの多孔体薄膜の表面へのシトクロムｃの吸着量の比較である。4 is a comparison of the amount of cytochrome c adsorbed on the surface of a porous thin film of various titanium oxides of Example 4. FIG. 実施例４の大孔径ナノ空間を有する酸化チタンと酸化スズの透明薄膜の表面へのシトクロムｃの吸着量の比較を示したグラフである。It is the graph which showed the comparison of the adsorption amount of the cytochrome c to the surface of the transparent thin film of the titanium oxide which has a large pore diameter nanospace of Example 4, and a tin oxide. 実施例５の各種酸化チタンの多孔体薄膜表面へのＣｙ５－ｓｓＤＮＡの吸着量の比較を示したグラフである。6 is a graph showing a comparison of the amount of Cy5-ssDNA adsorbed on the surface of a porous thin film of various titanium oxides of Example 5. FIG. 実施例５の大孔径ナノ空間を有する酸化チタン薄膜表面に固定化したＣｙ５－ｓｓＤＮＡを１２０ｍＷの光で励起した場合に発生する光電流と各種酸化チタンの多孔体薄膜との比較を示したグラフである。FIG. 7 is a graph showing a comparison between photocurrent generated when Cy5-ssDNA immobilized on the surface of a titanium oxide thin film having a large pore nanospace in Example 5 is excited with 120 mW light and various porous thin films of titanium oxide. is there. 実施例５の大孔径ナノ空間を有する酸化チタン薄膜表面に固定化したＣｙ５－ｓｓＤＮＡを６ｍＷの光で励起した場合に発生する光電流と各種酸化チタンの多孔体薄膜との比較を示したグラフである。FIG. 6 is a graph showing a comparison between photocurrent generated when Cy5-ssDNA immobilized on the surface of a titanium oxide thin film having a large pore nanospace of Example 5 is excited with 6 mW light and various porous thin films of titanium oxide. is there. 実施例６の４００℃焼成した大孔径ナノ空間を有する酸化チタン薄膜表面へのＣｙ５－ＸＧ６９の吸着を示したグラフである。6 is a graph showing the adsorption of Cy5-XG69 on the surface of a titanium oxide thin film having a large pore diameter nanospace baked at 400 ° C. in Example 6. 実施例６の大孔径ナノ空間を有する酸化チタン薄膜表面に固定化したＣｙ５－ＸＧ６９を１２０ｍＷの光で励起した場合に発生する光電流と各種酸化チタンの多孔体薄膜との比較を示したグラフである。FIG. 6 is a graph showing a comparison between photocurrent generated when Cy5-XG69 immobilized on the surface of a titanium oxide thin film having a large pore nanospace in Example 6 is excited with 120 mW light and various porous thin films of titanium oxide. is there. 実施例６の４５０℃焼成した大孔径ナノ空間を有する酸化スズ薄膜表面での抗原抗体反応を経て吸着する２次抗体からの蛍光値測定結果を示すグラフである。It is a graph which shows the fluorescence value measurement result from the secondary antibody which adsorb | sucks through the antigen antibody reaction in the tin-oxide thin film surface which has the large-pore diameter nano space baked at 450 degreeC of Example 6. 実施例６の４５０℃焼成した大孔径ナノ空間を有する酸化スズ薄膜表面での抗原抗体反応を経て吸着する２次抗体に標識したＣｙ５からの光電流測定結果を示すグラフである。It is a graph which shows the photocurrent measurement result from Cy5 labeled to the secondary antibody adsorbed through the antigen-antibody reaction on the surface of the tin oxide thin film having a large pore diameter nanospace baked at 450 ° C. in Example 6.
　次に、本発明について更に詳細に説明する。 Next, the present invention will be described in further detail.
　本発明に用いる遷移金属酸化物の金属原料としては、チタン、スズ又は亜鉛の金属塩及び金属アルコキシドの内から選択される１種以上を用いることができる。 As the metal raw material of the transition metal oxide used in the present invention, one or more selected from a metal salt of titanium, tin or zinc and a metal alkoxide can be used.
　前記金属原料を遷移金属酸化物とするには、エタノール溶液に金属塩を添加する方法、また、金属アルコキシドに塩酸を加えて加水分解する方法により調製することができる。 In order to make the metal raw material a transition metal oxide, it can be prepared by a method of adding a metal salt to an ethanol solution, or a method of hydrolyzing a metal alkoxide by adding hydrochloric acid.
　上記金属原料を用いることにより、例えば、反応時に塩化物から塩化水素が発生する或いは塩酸を添加することで溶液が塩酸酸性になっていれば、後述する界面活性剤の親水性部がプロトン化され、溶解無機種との相互作用が強くなる。 By using the metal raw material, for example, if hydrogen chloride is generated from chloride during the reaction or the solution is acidified by adding hydrochloric acid, the hydrophilic portion of the surfactant described later is protonated. , Interaction with dissolved inorganic species becomes stronger.
　また、金属アルコキシドを用いた場合にも、反応を制御する目的と同時に、塩酸を添加して酸性の前駆溶液を調製すればよく、最終的に無機原料を含む溶液が塩酸酸性であれば各種金属塩（硝酸塩、酢酸塩等）を出発原料に用いても問題はない。塩化物とアルコキシドを混合するだけでも酸化物ネットワークの形成が促され、同時に塩化水素が発生して酸性の前駆溶液を調製することができる。 In addition, when metal alkoxide is used, it is sufficient to prepare an acidic precursor solution by adding hydrochloric acid at the same time as the purpose of controlling the reaction. There is no problem even if a salt (nitrate, acetate, etc.) is used as a starting material. Even by mixing the chloride and the alkoxide, the formation of an oxide network is promoted, and at the same time, hydrogen chloride is generated to prepare an acidic precursor solution.
　本発明に用いられる界面活性剤は、親水的な役割を果たすＰＥＯユニットと疎水的な役割を果たすＰＳユニットから構成されるブロック共重合体である。 The surfactant used in the present invention is a block copolymer composed of a PEO unit that plays a hydrophilic role and a PS unit that plays a hydrophobic role.
　上記界面活性剤を本発明の製造方法に適用するには、溶媒に上記の界面活性剤を溶解して界面活性剤溶液を調製する。 In order to apply the above surfactant to the production method of the present invention, the above surfactant is dissolved in a solvent to prepare a surfactant solution.
　界面活性剤溶液を調製するためにはＰＳｎ－ｂ－ＰＥＯｍを完全に溶解することが可能な溶媒の選択が重要である。ＰＳｎ－ｂ－ＰＥＯｍは各種溶媒への溶解性が低いためにその選択は容易ではないが、例えば、溶媒にはテトラヒドロフラン（以下、ＴＨＦと略称する）が好ましく、ＴＨＦとエタノールとの混合溶媒を用いることで比較的容易に透明な界面活性剤溶液を調製することができる。また、ジオキサン等の極性溶媒もＰＳｎ－ｂ－ＰＥＯｍを溶解する能力に優れており好適に用いることができる。 In order to prepare a surfactant solution, it is important to select a solvent capable of completely dissolving PS n -b-PEO m . PS n -b-PEO m is not easily selected because of its low solubility in various solvents. For example, tetrahydrofuran (hereinafter abbreviated as THF) is preferable as the solvent, and a mixed solvent of THF and ethanol. By using this, a transparent surfactant solution can be prepared relatively easily. A polar solvent such as dioxane is also excellent in the ability to dissolve PS n -b-PEO m and can be suitably used.
　ＰＥＯユニットは、溶液中で溶解無機種と水素結合によって相互作用することが可能であり、また、塩酸酸性溶液中で使用することでプロトン化したＰＥＯユニットと溶解無機種がより強く静電的に相互作用し、界面活性剤が自己集合する過程でも親水性部近傍に安定的に無機種を存在させることができ、無機種間の結合生成等を経て、無機有機メソ構造体を生成させることができるため好ましい。 PEO units can interact with dissolved inorganic species in solution by hydrogen bonding, and when used in acidic hydrochloric acid, protonated PEO units and dissolved inorganic species are more strongly and electrostatically Even in the process of interaction and surfactant self-assembly, inorganic species can exist stably in the vicinity of the hydrophilic part, and inorganic organic mesostructures can be generated through bond formation between inorganic species. This is preferable because it is possible.
　疎水性を示すユニットをＰＳユニットとする理由は、親水性と疎水性の差が大きい場合には、分子量の大きい、即ち重合度の大きいブロック共重合体を用いた場合にも界面活性剤としての自己集合構造を形成するからである。例えば、ＥＯｎＰＯｍＥＯｎを用いたメソ多孔体の合成は世界中から数多く論文報告されているが、ユニット毎の重合数は最大でも１００程度である。それ以上の重合度のＥＯｎＰＯｍＥＯｎを利用すると相分離を起こすようになるために、ナノレベルでの構造規則性を付与するために利用しずらくなる。そのため、ポリオキシプロピレン鎖ではなく、疎水性の強いＰＳユニットを含むブロック共重合体が大孔径ナノ空間を有する化合物の構造規定剤として必要となる。 The reason why the unit exhibiting hydrophobicity is a PS unit is that when the difference between hydrophilicity and hydrophobicity is large, the surfactant is used even when a block copolymer having a large molecular weight, that is, a high degree of polymerization is used. This is because a self-assembled structure is formed. For example, many synthesizing mesoporous materials using EO n PO m EO n have been reported from all over the world, but the maximum number of polymerizations per unit is about 100. When EO n PO m EO n having a degree of polymerization higher than that is used, phase separation occurs, which makes it difficult to use the structure regularity at the nano level. Therefore, not a polyoxypropylene chain but a block copolymer containing a strongly hydrophobic PS unit is required as a structure-directing agent for a compound having a large pore nanospace.
　ＰＥＯ－ＰＳジブロック共重合体以外にも、ＰＥＯ－ＰＳ－ＰＥＯトリブロック共重合体であっても親水性と疎水性の差は同様であるので、大孔径ナノ空間を有する化合物の構造規定剤として利用することができる。 In addition to the PEO-PS diblock copolymer, the difference in hydrophilicity and hydrophobicity is the same even in the case of the PEO-PS-PEO triblock copolymer. Can be used as
　ＰＳｎ－ｂ－ＰＥＯｍ等の親水性と疎水性の差が大きいユニットから構成されるブロック共重合体は、極性溶媒中では球状に自己集合する性質が強い。そのため、大孔径ナノ空間を有する遷移金属酸化物の透明薄膜のナノ構造が、界面活性剤の自己集合によって規定される球状の大孔径ナノ空間の集合体であるとしている。 A block copolymer composed of units having a large difference between hydrophilicity and hydrophobicity such as PS n -b-PEO m has a strong property of self-assembling spherically in a polar solvent. For this reason, the nanostructure of the transparent thin film of transition metal oxide having a large pore nanospace is assumed to be an aggregate of spherical large pore nanospaces defined by the self-assembly of the surfactant.
　用いるブロック共重合体の分子量分布が広いと、会合数や分子量の違いから球状の集合体にもサイズのばらつきが生じるため、ナノ孔の集合が不規則になる場合がある。 When the molecular weight distribution of the block copolymer used is wide, the size of the spherical aggregates varies due to the difference in the number of associations and molecular weights, and the assembly of nanopores may become irregular.
　一方、分子量分布が狭い場合には均一なナノ孔が生成し易く、大孔径ナノ空間が規則的に集合する傾向がある。しかし、無機種との相互作用の程度によっても親水部の見かけの分子量が変化するために最適条件下では規則性が高くなることがある。従って、球状粒子の規則的な積層構造として、各種立方構造及び三次元六方構造を有する大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の製造も可能である。 On the other hand, when the molecular weight distribution is narrow, uniform nanopores are likely to be generated, and large-pore nanospaces tend to regularly gather. However, the apparent molecular weight of the hydrophilic portion varies depending on the degree of interaction with the inorganic species, and the regularity may increase under the optimum conditions. Therefore, it is possible to produce a transparent thin film of transition metal oxide having a large pore size nanospace having various cubic structures and three-dimensional hexagonal structures as a regular laminated structure of spherical particles.
　直径が３０ｎｍを超える大孔径ナノ空間を有する遷移金属酸化物の透明薄膜を得るためには、ＰＳｎ－ｂ－ＰＥＯｍの重合数、特に球状集合体のコア部分に相当するＰＳユニットの重合数が重要である。 In order to obtain a transparent thin film of transition metal oxide having a large pore nanospace with a diameter exceeding 30 nm, the number of polymerizations of PS n -b-PEO m , particularly the number of polymerizations of PS units corresponding to the core portion of the spherical assembly is important.
　例えば、ＰＳｎ－ｂ－ＰＥＯｍが１分子で球状の集合体を形成すると仮定すると、ＰＳユニットの密度を１．０６ｇｃｍ-３（１００ｎｍラテックス球の密度を参考）、ＰＳ３５－ｂ－ＰＥＯ１０９では直径１０ｎｍ（シリカでは１０ｎｍ）（非特許文献２参照）、ＰＳ２３０－ｂ－ＰＥＯ１２５では直径が２０ｎｍ（シリカでは３１ｎｍ）（非特許文献２参照）の球状のＰＳ部分が生成していると計算できる。即ち、ＰＳユニットの重合数と孔径が単純な比例関係にあるわけではなく、重合数が大きなＰＳｎ－ｂ－ＰＥＯｍを用いた場合には数分子が会合していると解釈することができる。 For example, assuming that PS n -b-PEO m forms a spherical aggregate with one molecule, the density of PS units is 1.06 gcm −3 (refer to the density of 100 nm latex spheres), and PS 35 -b-PEO 109 Then, a spherical PS portion having a diameter of 10 nm (10 nm for silica) (see Non-Patent Document 2) and PS 230 -b-PEO 125 having a diameter of 20 nm (31 nm for silica) (see Non-Patent Document 2) is generated. Can be calculated. That is, the number of polymerization of the PS unit and the pore size are not in a simple proportional relationship, and when PS n -b-PEO m having a large polymerization number is used, it can be interpreted that several molecules are associated. .
　例えば、ＰＳ２３０－ｂ－ＰＥＯ１２５を用いた合成で孔径が３０ｎｍ程度の多孔体が生成しているならば（非特許文献３参照）、少なくとも４分子前後のＰＳ２３０－ｂ－ＰＥＯ１２５分子が会合していると解釈できる。 For example, if a porous body having a pore size of about 30 nm is generated by synthesis using PS 230 -b-PEO 125 (see Non-Patent Document 3), at least about 4 PS 230 -b-PEO 125 molecules are present. It can be interpreted as meeting.
　例えば、１分子集合体で直径３０ｎｍのＰＳユニットのコア部分の生成を実現するためにはＰＳユニットの分子量が１０００００（重合数は約９６０）程度のものが必要であり、数分子が会合することができれば、更に大きなＰＳユニットのコア部分が生成すると予想できる。 For example, in order to realize generation of the core part of a PS unit having a diameter of 30 nm in one molecule assembly, the PS unit must have a molecular weight of about 100,000 (the number of polymerization is about 960), and several molecules should be associated. If possible, it can be expected that a larger PS unit core will be generated.
　しかしながら、このような巨大な界面活性剤分子が単独で球状粒子を生成するか、又は複数分子が集合するのか、相分離を起こすのかは明らかにはなっていない。加えて、重合数の増大は溶解性を大きく低下させてしまうために、透明な前駆溶液を調製できるかも疑問である。球状粒子の生成或いは複数分子からなる集合体の形成が可能であると仮定すると、例えば、ＰＳユニットの分子量が１０００００の場合に５０ｎｍになるには５分子、１００ｎｍになるには３２分子、１５０ｎｍになるには１０８分子が会合する必要があるとすることができる。 However, it is not clear whether such a large surfactant molecule alone generates spherical particles, or a plurality of molecules aggregate or cause phase separation. In addition, since the increase in the number of polymerizations greatly reduces the solubility, it is doubtful that a transparent precursor solution can be prepared. Assuming that the generation of spherical particles or the formation of an assembly consisting of a plurality of molecules is possible, for example, when the molecular weight of the PS unit is 100,000, 5 molecules will be 50 nm, 32 molecules will be 100 nm, and 108 molecules will be 150 nm. It may be necessary to meet.
　一般に界面活性剤の会合数は分子量が大きいほど大きくなるとされているので、重合数と会合能力の両方を考慮して界面活性剤の分子構造を規定することができ、実際に直径が３０ｎｍを超える大孔径ナノ空間を有する化合物を得るためには、ＰＳユニットの重合数と会合数の両方を同時に考慮する必要がある。 In general, the number of associations of a surfactant increases with an increase in molecular weight. Therefore, the molecular structure of the surfactant can be defined in consideration of both the number of polymerizations and the association ability, and the diameter actually exceeds 30 nm. In order to obtain a compound having a large pore nanospace, it is necessary to consider both the number of polymerizations and the number of associations of the PS unit at the same time.
　従って、ＰＳユニットの重合数が３００程度であれば３分子が会合すると３０ｎｍ余りのＰＳコア部分の形成は可能であると考えられる。重合数を４０００程度まで増大しても、１分子で５０ｎｍ程度の球状の集合体の形成が可能であり、１５０ｎｍのＰＳユニットのコア部分を形成するには会合数が３０分子程度あればよい。 Therefore, if the number of polymerized PS units is about 300, it is considered that a PS core portion of about 30 nm can be formed when three molecules are associated. Even if the number of polymerizations is increased to about 4000, it is possible to form a spherical aggregate of about 50 nm with one molecule. To form the core part of a 150 nm PS unit, the number of associations should be about 30 molecules.
　ＰＳｎ－ｂ－ＰＥＯｍの重合数としては生成したコア部分を取り囲むことが可能であれば、ＰＥＯユニットの重合数（ｍ）にそれほど厳密な制限はない。 The number of polymerization of PS n -b-PEO m is not so strict as long as the generated core portion can be surrounded.
　ただし、ＰＳユニットの重合数が大きくなると溶解性が大きく低下することが考慮されるので透明な前駆溶液を調製するための溶媒の選択が重要になる。 However, since it is considered that the solubility greatly decreases as the number of polymerized PS units increases, it is important to select a solvent for preparing a transparent precursor solution.
　ＰＥＯユニットはシェル部分に相当し、その部分と相互作用して骨格を形成する遷移金属種の量が多すぎると折角生成した大きな孔は孤立してしまう。直径が３０～１５０ｎｍのような大孔径ナノ空間を有する遷移金属酸化物の透明薄膜が得られても、１０ｎｍを超えるような生体関連分子を選択的かつ大量にハンドリングするのに十分なサイズの連結孔が必ずしも存在しているわけではない。 The PEO unit corresponds to a shell portion, and if the amount of transition metal species that interact with the portion to form a skeleton is too large, the large holes that are generated at the corner are isolated. Even when a transparent thin film of a transition metal oxide having a large pore nanospace with a diameter of 30 to 150 nm can be obtained, the size of the linkage is sufficient to selectively handle a large amount of biologically relevant molecules exceeding 10 nm. The holes are not necessarily present.
　ＰＥＯユニットの重合数とも関連しながら、大孔径ナノ空間周囲の壁厚は無機原料の供給量によって概ね決定するので、その量を制御して壁厚を薄くしていくことで連結孔を制御することができる。 Although the wall thickness around the large pore size nano space is largely determined by the amount of inorganic raw material supplied, it is related to the number of polymerizations of the PEO unit, so the connection hole is controlled by reducing the wall thickness by controlling that amount. be able to.
　本発明の所望の連結孔を形成するための透明な前駆溶液の調製は、酸化チタンの場合、ＰＳ－ｂ－ＰＥＯ／溶媒（ＴＨＦ：エタノール＝４：１）の重量比で、０．５～１．２の範囲で球状のマクロ孔が形成し、０．８～１．０の範囲で連結孔の生成が多くなり好ましい。１．２～２．０の範囲では球状のマクロ孔は消失し、酸化物粒子が生成する。 In the case of titanium oxide, the preparation of the transparent precursor solution for forming the desired connection hole of the present invention is performed at a weight ratio of PS-b-PEO / solvent (THF: ethanol = 4: 1) from 0.5 to In the range of 1.2, spherical macropores are formed, and in the range of 0.8 to 1.0, the generation of connecting holes is preferred. In the range of 1.2 to 2.0, the spherical macropores disappear and oxide particles are generated.
　具体的には、例えば、ＰＳ９６０－ｂ－ＰＥＯ３４００（０．０８ｇ）を体積比４：１のＴＨＦ／エタノール（１１．２５ｍＬ）に溶解した混合溶媒に対し、チタンテトラプロポキシド（０．１３５ｇ）に濃塩酸（０．２９６ｍＬ）を加水分解したものを混合して調製した前駆溶液を挙げることができ、また、ＰＳ９６０－ｂ－ＰＥＯ３４００（０．０８ｇ）を、体積比４：１のＴＨＦ／エタノール（１１．２５ｍＬ）に溶解した混合溶媒に対し、無水二塩化スズ（０．０６ｇ）に濃塩酸（０．２９６ｍＬ）を加水分解して純水（０．２ｍＬ）を添加したものを混合して調製した前駆溶液、ＰＳ９６０－ｂ－ＰＥＯ３４００（０．０８ｇ）を、体積比４：１のＴＨＦ／エタノール（１１．２５ｍＬ）に溶解した混合溶媒に対し、塩酸酸性下、無水酢酸亜鉛（０．０８７ｇ）から調製された前駆溶液等を挙げることができる。 Specifically, for example, titanium tetrapropoxide (0.135 g) is added to a mixed solvent in which PS 960 -b-PEO 3400 (0.08 g) is dissolved in THF / ethanol (11.25 mL) at a volume ratio of 4: 1. ) And a precursor solution prepared by mixing hydrolyzed concentrated hydrochloric acid (0.296 mL), PS 960 -b-PEO 3400 (0.08 g) was added at a volume ratio of 4: 1. To a mixed solvent dissolved in THF / ethanol (11.25 mL), anhydrous tin dichloride (0.06 g) was hydrolyzed with concentrated hydrochloric acid (0.296 mL) and pure water (0.2 mL) was added. mixed to prepare a precursor solution, PS 960 -b-PEO 3400 a (0.08 g), a volume ratio of 4: for mixed solvent dissolved in 1 THF / ethanol (11.25 mL), hydrochloric acid Sex under include a precursor solution prepared from anhydrous zinc acetate (0.087 g) and the like.
　また、逆にＰＥＯユニットの重合数を減らしても、相互作用によりシェル部分に存在できる無機種の量が制御できるので、その重合数と無機原料の添加量の合成条件を最適化することにより壁厚を制御して連結孔を制御することができる。 Conversely, even if the polymerization number of the PEO unit is reduced, the amount of inorganic species that can be present in the shell portion can be controlled by interaction, so the wall condition can be achieved by optimizing the synthesis conditions of the polymerization number and the addition amount of the inorganic raw material. The connection hole can be controlled by controlling the thickness.
　上記のように、大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の構造とＰＳｎ－ｂ－ＰＥＯｍの分子構造とは大きく関係していることは言うまでもなく、ＰＳｎ－ｂ－ＰＥＯｍの分子量分布は孔径分布、重合数は孔径や溶解性に主に影響すること等を考慮して、ＴＨＦ／エタノール比、溶媒量、塩酸量、反応時間等種々の合成条件を適宜調製して所望の透明薄膜を得ることが可能となる。ＰＳｎ－ｂ－ＰＥＯｍ自身が単独でも溶媒中で球状に集合する傾向が強いことから、透明な前駆溶液を調製することが極めて重要である。ただし、透明薄膜全体に大孔径ナノ空間を導入するためにはＰＳｎ－ｂ－ＰＥＯｍに対する遷移金属種の量も重要であり、このことは球状のナノ空間の連結性にも大きく影響する。 As described above, it goes without saying that the structure of a transparent thin film of transition metal oxide having a large pore nanospace and the molecular structure of PS n -b-PEO m are largely related to PS n -b-PEO m. In consideration of the molecular weight distribution of the pore size distribution, the number of polymerizations mainly affecting the pore size and solubility, etc., various synthesis conditions such as the THF / ethanol ratio, the amount of solvent, the amount of hydrochloric acid, the reaction time, etc. are appropriately adjusted and desired It becomes possible to obtain a transparent thin film. Since PS n -b-PEO m itself has a strong tendency to assemble into a spherical shape in a solvent, it is extremely important to prepare a transparent precursor solution. However, the amount of transition metal species relative to PS n -b-PEO m is also important in order to introduce a large pore nanospace into the entire transparent thin film, and this greatly affects the connectivity of the spherical nanospace.
　次に、大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の具体的な製造方法について説明する。 Next, a specific method for producing a transition metal oxide transparent thin film having a large pore nanospace will be described.
　遷移金属種を含む透明な前駆溶液を調製するためには、エタノール溶液に塩化物を添加して得られた酸性溶液或いはアルコキシドに濃塩酸を加えて加水分解した溶液を、別に調製した界面活性剤溶液と混合する。 In order to prepare a transparent precursor solution containing a transition metal species, an acidic solution obtained by adding chloride to an ethanol solution or a solution obtained by hydrolyzing alkoxide with concentrated hydrochloric acid is separately prepared. Mix with solution.
　得られた透明な前駆溶液を基板上に成膜した後、界面活性剤を除去して、大孔径ナノ空間を有する遷移金属酸化物の透明薄膜を得る。 After the obtained transparent precursor solution is formed on a substrate, the surfactant is removed to obtain a transparent thin film of transition metal oxide having a large pore nanospace.
　上記基板としては、表面が平滑であり、成膜に支障をきたすものでなければ特に制限はなく、例えば、ガラス、石英、シリコン、単結晶ＩＴＯ、グラファイト、テフロン(登録商標)等の基板を好適に用いることができる。 The substrate is not particularly limited as long as it has a smooth surface and does not interfere with film formation. For example, a substrate such as glass, quartz, silicon, single crystal ITO, graphite, or Teflon (registered trademark) is preferable. Can be used.
　また、成膜のための塗布方法としては、スピンコート、ディップコート等の公知の方法により塗布することができる。これらの方法によれば、スピンコート速度や、ディップコートの引き上げ速度等の塗布条件を適宜調製することにより膜厚をコントロールすることができる。 Also, as a coating method for film formation, it can be applied by a known method such as spin coating or dip coating. According to these methods, the film thickness can be controlled by appropriately adjusting coating conditions such as spin coating speed and dip coating pulling speed.
　成膜した薄膜から界面活性剤を除去する方法としては、焼成又は、ＵＶオゾン処理により除去することができる。 As a method for removing the surfactant from the formed thin film, it can be removed by baking or UV ozone treatment.
　焼成による界面活性剤の除去条件としては、例えば、２５０℃という低温でも界面活性剤を除去することは可能であり、その際には遷移金属種は非晶質構造のままで大孔径ナノ空間を有する遷移金属酸化物の透明薄膜を得ることができる。また、遷移金属種により結晶化温度は異なるが、更に高温で処理しても大孔径ナノ空間の構造は崩壊することなく、遷移金属種が結晶化した大孔径ナノ空間を有する遷移金属酸化物の透明薄膜を得ることができる。 As a condition for removing the surfactant by firing, for example, it is possible to remove the surfactant even at a low temperature of 250 ° C. In this case, the transition metal species remains in an amorphous structure and a large pore size nanospace is formed. A transparent thin film of a transition metal oxide can be obtained. In addition, although the crystallization temperature differs depending on the transition metal species, the structure of the large pore nanospace where the transition metal species is crystallized does not collapse even when processed at a higher temperature. A transparent thin film can be obtained.
　球状のＰＳｎ－ｂ－ＰＥＯｍ集合体を大量に含む遷移金属酸化物薄膜は透明性が高いため、上記の焼成による界面活性剤除去の他、紫外線照射によるＵＶオゾン処理によっても界面活性剤を除去することがでる。 Since the transition metal oxide thin film containing a large amount of spherical PS n -b-PEO m aggregates has high transparency, in addition to the removal of the surfactant by the above baking, the surfactant is also removed by UV ozone treatment by ultraviolet irradiation. It can be removed.
　低温での焼成又は、ＵＶオゾン処理により界面活性剤を除去した場合には、非晶質な骨格構造の酸化チタン、酸化スズ又は酸化亜鉛からなる大孔径ナノ空間を有する遷移金属酸化物の透明薄膜を得ることができる。また、酸化チタン、酸化スズ又は酸化亜鉛それぞれの結晶化温度以上で焼成して界面活性剤を除去すると、同時に骨格構造の結晶化が徐々に進行し、微結晶を含む（非晶質構造と結晶構造の中間相）構造から特有の結晶構造を有する酸化チタン、酸化スズ又は酸化亜鉛からなる大孔径ナノ空間を有する遷移金属酸化物の透明薄膜を得ることが可能となる。 When the surfactant is removed by baking at low temperature or UV ozone treatment, a transparent thin film of transition metal oxide having a large pore nanospace made of titanium oxide, tin oxide or zinc oxide having an amorphous skeleton structure Can be obtained. In addition, when the surfactant is removed by baking at a temperature higher than the crystallization temperature of each of titanium oxide, tin oxide, or zinc oxide, the crystallization of the skeleton structure proceeds gradually and includes microcrystals (amorphous structure and crystal It becomes possible to obtain a transparent thin film of a transition metal oxide having a large pore nanospace made of titanium oxide, tin oxide or zinc oxide having a unique crystal structure from the intermediate phase of the structure.
　以下に、本発明の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の利用方法について具体的に例示して説明する。 Hereinafter, the method for using the transparent thin film of transition metal oxide having a large pore nanospace according to the present invention will be described specifically by way of example.
　医薬品等の比較的大きな有機分子の関与する吸着分離、ＤＤＳ、触媒反応等の利用には、既存の１０ｎｍ以下の孔径のメソ多孔体でも十分に対応することができるが、タンパク質やＤＮＡ等の生体関連分子等は１０ｎｍを超えるような分子サイズを有するため、これらの分子を選択的かつ大量にハンドリングすることは困難である。 Existing mesoporous materials with a pore size of 10 nm or less can be adequately used for adsorption separation, DDS, catalytic reaction, etc. involving relatively large organic molecules such as pharmaceuticals, but biological materials such as proteins and DNA Since related molecules have a molecular size exceeding 10 nm, it is difficult to handle these molecules selectively and in large quantities.
　本発明の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜によれば、遷移金属酸化物の透明薄膜内に直径が３０～１５０ｎｍの範囲に大孔径ナノ空間が大量に存在し、１０ｎｍを超えるような生体関連分子を選択的かつ大量にハンドリングするのに十分なサイズの連結孔を有しているので、酵素反応等に代表されるように、タンパク質やＤＮＡ等の生体内では極めて選択的かつ効率的に各種反応に重要な役割を果たすような機能性有機化合物を取り扱うための特異反応場とすることができる。 According to the transparent thin film of transition metal oxide having a large pore nanospace of the present invention, a large amount of large pore nanospace exists in the range of 30 to 150 nm in the transparent thin film of transition metal oxide, and exceeds 10 nm. Since it has a connecting hole of sufficient size to handle such biologically relevant molecules selectively and in large quantities, it is extremely selective in vivo in proteins and DNA, as represented by enzyme reactions and the like. It can be a specific reaction field for handling functional organic compounds that play an important role in various reactions efficiently.
　大孔径ナノ空間を構築する遷移金属酸化物の表面との相互作用を利用することで、機能性色素分子を選択的かつ大量に吸着させることができ、機能性色素分子が強く固定化できる場合には混合物からの分離も可能である。 When the functional dye molecules can be adsorbed selectively and in large quantities by utilizing the interaction with the surface of the transition metal oxide that constructs the large pore nanospace, the functional dye molecules can be strongly immobilized Can also be separated from the mixture.
　また、本発明の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜を電極材料として用いることもできる。 Moreover, the transparent thin film of transition metal oxide having a large pore nanospace of the present invention can also be used as an electrode material.
　Ｇｒａｔｚｅｌ型の色素増感太陽電池（非特許文献６参照）に関する研究では、酸化チタン、酸化スズ、酸化亜鉛、酸化タングステン等の遷移金属酸化物と色素との各種組み合わせが検討されているが、酸化チタンとルテニウム錯体との組み合わせを超えるような変換効率を示すものは見つかっていない。例えば、酸化チタンのナノ結晶粒子とルテニウム錯体との組み合わせで変換効率１０％を実現したと報告されている（非特許文献７～９参照）。これには、酸化チタン電極をナノ粒子で設計しているのは色素分子（ルテニウム錯体）の吸着量をより多くするためであるということが記されている。 In research on Gratzel type dye-sensitized solar cells (see Non-Patent Document 6), various combinations of transition metal oxides such as titanium oxide, tin oxide, zinc oxide, and tungsten oxide with dyes have been studied. Nothing has been found that shows conversion efficiency exceeding the combination of titanium and ruthenium complex. For example, it has been reported that a conversion efficiency of 10% is realized by a combination of titanium oxide nanocrystal particles and a ruthenium complex (see Non-Patent Documents 7 to 9). This describes that the titanium oxide electrode is designed with nanoparticles in order to increase the amount of dye molecules (ruthenium complex) adsorbed.
　本発明の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜は極めて有用な電極材料として、色素分子の吸着量を大幅に増大させられるだけでなく、薄膜の透明性が極めて高いために光エネルギーの効率的な変換も期待できる。 The transition metal oxide transparent thin film having a large pore nanospace according to the present invention is not only an extremely useful electrode material, but also can greatly increase the amount of dye molecules adsorbed, and also has a very high thin film transparency. An efficient conversion can be expected.
　即ち、大量の機能性色素分子が酸化チタン、酸化スズ及び酸化亜鉛の大孔径ナノ空間の表面に強く固定化することができ、光エネルギーを大量に色素分子で捕捉して半導体電極へ移動させられるので、本発明の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜は色素増感太陽電池の電極材料として有効に用いることができる。 That is, a large amount of functional dye molecules can be strongly immobilized on the surface of the large pore nanospace of titanium oxide, tin oxide and zinc oxide, and a large amount of light energy can be captured by the dye molecules and transferred to the semiconductor electrode. Therefore, the transparent thin film of transition metal oxide having a large pore nanospace of the present invention can be effectively used as an electrode material for a dye-sensitized solar cell.
　更に、色素増感の原理を利用したセンサー系の構築にも、本発明の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜を電極材料として利用することができる。 Furthermore, the transition metal oxide transparent thin film having a large pore nanospace of the present invention can be used as an electrode material for the construction of a sensor system using the principle of dye sensitization.
　例えば、ごく微量でも毒性の高い環境ホルモンを高感度にセンシングするために、標識色素を利用して色素増感型デバイスを構成する。環境ホルモンとして疑われている化学物質（ダイオキシン類、エストラジオール、ビスフェノールＡ等）を可能な限り大量かつ選択的に半導体電極表面に吸着させることが高感度化にとって極めて重要となる。色素増感太陽電池では、光励起した色素からエネルギーが半導体電極に移動して電流が発生するという原理で太陽光の利用が可能になる。 For example, a dye-sensitized device is constructed using a labeling dye in order to highly sensitively detect environmental hormones that are highly toxic even in very small amounts. It is extremely important for high sensitivity to adsorb chemical substances (dioxins, estradiol, bisphenol A, etc.) suspected as environmental hormones on the surface of the semiconductor electrode as much as possible and selectively. In a dye-sensitized solar cell, sunlight can be used on the principle that energy is transferred from a photoexcited dye to a semiconductor electrode to generate a current.
　センサー系では、光励起された標識色素から発生する蛍光或いは電子（光電流）をそれぞれ蛍光スペクトル測定或いは電流計を用いて検出する。例えば、電極表面に色素標識したＤＮＡを固定化すると、ダイオキシン類が極めて選択的にＤＮＡ分子と相互作用する。吸着と同時に標識色素が変性するので、変性した色素からの蛍光或いは光電流を検出することで高感度にダイオキシン類をセンシングできる。このときのＤＮＡをダイオキシン受容体と呼ぶ。エストラジオール受容体を電極表面に固定化しておけば、エストラジオールを高感度にセンシングできる。酸化チタン、酸化スズ及び酸化亜鉛いずれの大孔径ナノ空間を有する透明電極でも大量にＤＮＡ分子を固定化できる。 In the sensor system, fluorescence or electrons (photocurrent) generated from the photoexcited labeling dye are detected using a fluorescence spectrum measurement or an ammeter, respectively. For example, when dye-labeled DNA is immobilized on the electrode surface, dioxins interact with DNA molecules very selectively. Since the labeling dye is denatured simultaneously with the adsorption, dioxins can be sensed with high sensitivity by detecting fluorescence or photocurrent from the denatured dye. The DNA at this time is called a dioxin receptor. If the estradiol receptor is immobilized on the electrode surface, estradiol can be sensed with high sensitivity. A large amount of DNA molecules can be immobilized even on a transparent electrode having a large pore nanospace such as titanium oxide, tin oxide and zinc oxide.
　ビスフェノールＡの場合には、抗原抗体反応（モノクローナル抗体）を利用することで選択的な捕捉が可能である。抗体（１次）を電極表面に固定化し、ビスフェノールＡが存在する場合に限り、抗原がビスフェノールＡ挟み込む形で抗体（２次）と反応する。即ち、２次抗体を色素標識しておくことで、色素増感の原理を利用したセンシングが可能になる。 In the case of bisphenol A, selective capture is possible by using an antigen-antibody reaction (monoclonal antibody). The antibody (primary) is immobilized on the electrode surface, and only when bisphenol A is present, the antigen reacts with the antibody (secondary) in the form of bisphenol A sandwiched. That is, when the secondary antibody is dye-labeled, sensing using the principle of dye sensitization becomes possible.
　次に、実施例に基づいて本発明を具体的に説明するが、本発明は以下の実施例によって何ら限定されるものではない。 Next, the present invention will be specifically described based on examples, but the present invention is not limited to the following examples.
　ＰＳｎ－ｂ－ＰＥＯｍとして、ＰＳユニットの数平均分子量が１００，０００（重合数が約９６０）、ＰＥＯユニットの数平均分子量１５０，０００（重合数が約３４００）のもの（ＰＳ９６０－ｂ－ＰＥＯ３４００）を用いて大孔径ナノ空間を有する酸化チタンの透明薄膜の合成を行った。ＰＳ９６０－ｂ－ＰＥＯ３４００（０．０８ｇ）は、体積比４：１のＴＨＦ／エタノール（１１．２５ｍＬ）混合溶媒に完全に溶解した。次に、チタンテトラプロポキシド（０．１３５ｇ）に濃塩酸（０．２９６ｍＬ）をゆっくり滴下して予め加水分解した透明な溶液を調製し、その後界面活性剤の溶液と混合して透明な前駆溶液を得た。得られた溶液をガラス基板上にスピンコートすることで薄膜を得た。成膜直後に、酸化チタン骨格のネットワーク形成を減速さるために薄膜を－２０℃に冷却し、空気中の湿気で薄膜内部に霜が張る前までに５０℃での乾燥作業に進み、２５０℃或いは４００℃で焼成して界面活性剤の除去を行い、大孔径ナノ空間を有する酸化チタンの透明薄膜を得た。同様にして、重合数の少ないＰＳｎ－ｂ－ＰＥＯｍを利用することで、任意により小さい直径のナノ空間を有する酸化チタンの透明薄膜を得ることも可能であった。 PS n -b-PEO m having a PS unit number average molecular weight of 100,000 (polymerization number of about 960) and a PEO unit number average molecular weight of 150,000 (polymerization number of about 3400) (PS 960 -b -PEO 3400 ) was used to synthesize a transparent thin film of titanium oxide having a large pore nanospace. PS 960 -b-PEO 3400 (0.08 g) was completely dissolved in a mixed solvent of THF / ethanol (11.25 mL) at a volume ratio of 4: 1. Next, a concentrated solution (0.296 mL) is slowly added dropwise to titanium tetrapropoxide (0.135 g) to prepare a transparent hydrolyzed solution, which is then mixed with a surfactant solution to prepare a transparent precursor solution. Got. The thin film was obtained by spin-coating the obtained solution on a glass substrate. Immediately after the film formation, the thin film was cooled to −20 ° C. to slow down the formation of the titanium oxide skeleton network, and proceeded to a drying operation at 50 ° C. before frost was formed inside the thin film by moisture in the air. Alternatively, the surfactant was removed by baking at 400 ° C. to obtain a transparent thin film of titanium oxide having a large pore nanospace. Similarly, by using PS n -b-PEO m having a small number of polymerizations, it was possible to obtain a transparent thin film of titanium oxide having a nanospace with an arbitrarily smaller diameter.
　図１（ａ）に示す得られた薄膜のＳＥＭ観察から大孔径ナノ空間が薄膜全体に存在している様子が確認できた。この場合、ナノ空間の直径には分布があり、１０～２００ｎｍ、多くは３０～１５０ｎｍの範囲のナノ空間の存在を確認することができた。また、図１（ｂ）に示す高倍率でのＳＥＭ観察からは、大孔径ナノ空間が１０ｎｍより大きな孔によって連結している様子も確認することができた。 From the SEM observation of the obtained thin film shown in FIG. 1 (a), it was confirmed that large pore nanospace was present in the entire thin film. In this case, the diameter of the nanospace has a distribution, and the presence of the nanospace in the range of 10 to 200 nm, most of which is 30 to 150 nm, could be confirmed. In addition, from the SEM observation at a high magnification shown in FIG. 1B, it was also possible to confirm that the large pore nanospaces were connected by pores larger than 10 nm.
　透明前駆溶液をトレイで乾燥させて得られた粉末試料を２５０℃及び４００℃で焼成して、酸化チタン骨格の結晶性と焼成温度との関係をＸＲＤ測定した。その結果を図２に示す。２５０℃で焼成した場合にはほとんどが非晶質構造、４００℃で焼成した場合には酸化チタンのアナターゼ相に帰属可能な回折ピークの存在が確認できた。 The powder sample obtained by drying the transparent precursor solution in a tray was fired at 250 ° C. and 400 ° C., and the relationship between the crystallinity of the titanium oxide skeleton and the firing temperature was measured by XRD. The result is shown in FIG. The presence of diffraction peaks that can be attributed to the anatase phase of titanium oxide was confirmed in most cases when it was fired at 250 ° C., and when it was fired at 400 ° C.
　これにより、焼成温度によって、大孔径ナノ空間を有する遷移金属酸化物の骨格の結晶性を制御することができることが確認された。また、薄膜を削り取って、透過型電子顕微鏡で高倍率観察を行うと、４００℃で焼成した薄膜の骨格内部に５～１０ｎｍ程度のアナターゼ結晶が大量に存在している様子が見られた。スピンコート速度を８００～３０００ｒｐｍで成膜した結果、２５０℃或いは４００℃で焼成した後の膜厚は２００ｎｍ前後であった。クリプトン（Ｋｒ）ガス吸着測定により薄膜の多孔性を評価した結果、比表面積は３０ｍ２ｃｍ-３前後であった。 Thereby, it was confirmed that the crystallinity of the skeleton of the transition metal oxide having a large pore nanospace can be controlled by the firing temperature. Further, when the thin film was shaved and observed with a transmission electron microscope at a high magnification, it was observed that a large amount of anatase crystals of about 5 to 10 nm were present inside the skeleton of the thin film fired at 400 ° C. As a result of film formation at a spin coating speed of 800 to 3000 rpm, the film thickness after baking at 250 ° C. or 400 ° C. was about 200 nm. As a result of evaluating the porosity of the thin film by krypton (Kr) gas adsorption measurement, the specific surface area was about 30 m 2 cm −3 .
　ＰＳ９６０－ｂ－ＰＥＯ３４００を用いて大孔径ナノ空間を有する酸化スズの透明薄膜の合成を行った。ＰＳ９６０－ｂ－ＰＥＯ３４００（０．０８ｇ）を体積比４：１のＴＨＦ／エタノール（１０ｇ）混合溶媒に完全に溶解した。次に、無水二塩化スズ（０．０６ｇ）に濃塩酸（０．２９６ｍＬ）滴下して予め加水分解して得た溶液に純水（０．２ｍＬ）を添加し、ＰＳ９６０－ｂ－ＰＥＯ３４００溶液と混合して透明な前駆溶液を調製した。得られた溶液をガラス基板上にスピンコートすることで薄膜を得た。成膜直後に一端薄膜を－２０℃に冷却し、５０℃で乾燥した後に４５０℃で焼成して界面活性剤の除去を行った。 A transparent thin film of tin oxide having a large pore nanospace was synthesized using PS 960 -b-PEO 3400 . PS 960 -b-PEO 3400 (0.08 g) was completely dissolved in a THF / ethanol (10 g) mixed solvent having a volume ratio of 4: 1. Next, pure water (0.2 mL) was added to a solution obtained by hydrolyzing in advance by adding concentrated hydrochloric acid (0.296 mL) dropwise to anhydrous tin dichloride (0.06 g), and PS 960- b-PEO 3400 A clear precursor solution was prepared by mixing with the solution. The thin film was obtained by spin-coating the obtained solution on a glass substrate. Immediately after the film formation, the thin film was cooled to −20 ° C., dried at 50 ° C. and then fired at 450 ° C. to remove the surfactant.
　図３に示すＳＥＭ観察から、得られた薄膜の大孔径ナノ空間が薄膜全体に存在しており、ナノ空間の直径は１０～１５０ｎｍと見積もることができ、更に、大孔径ナノ空間が１０ｎｍより大きな孔によって連結してなる様子も確認できた。大孔径ナノ空間は酸化スズのナノ結晶によって取り囲まれている様子も確認されており、透明薄膜のＸＲＤ測定を直接行った結果、酸化スズ骨格が十分に結晶化していることが確認できた。そのＸＲＤ測定の結果を図４に示す。 From the SEM observation shown in FIG. 3, the large pore nanospace of the obtained thin film exists in the entire thin film, the diameter of the nanospace can be estimated to be 10 to 150 nm, and the large pore nanospace is larger than 10 nm. It was confirmed that the holes were connected by holes. It was confirmed that the large pore nanospace was surrounded by the tin oxide nanocrystals, and as a result of direct XRD measurement of the transparent thin film, it was confirmed that the tin oxide skeleton was sufficiently crystallized. The result of the XRD measurement is shown in FIG.
　以上より、大孔径ナノ空間を有する酸化スズの透明薄膜を得ることができたわけであるが、この場合には、スピンコート速度を１５００ｒｐｍとした結果、４５０℃焼成後の膜厚は約２００ｎｍ、Ｋｒガス吸着測定により算出した比表面積は約４０ｍ２ｃｍ-３であった。 From the above, it was possible to obtain a tin oxide transparent thin film having a large pore nanospace. In this case, as a result of setting the spin coating speed to 1500 rpm, the film thickness after baking at 450 ° C. was about 200 nm, Kr The specific surface area calculated by gas adsorption measurement was about 40 m 2 cm −3 .
　ＰＳ９６０－ｂ－ＰＥＯ３４００を用いて大孔径ナノ空間を有する酸化亜鉛の透明薄膜の合成を行った。ＰＳ９６０－ｂ－ＰＥＯ３４００（０．０８ｇ）を体積比４：１のＴＨＦ／エタノール（１１．７６ｍＬ）混合溶媒に完全に溶解した。次に、塩酸酸性下、無水酢酸亜鉛（０．０８７ｇ）から調製された透明溶液を界面活性剤溶液と混合して透明な前駆溶液を調製した。得られた溶液をガラス基板上にスピンコートすることで成膜し、完全に乾燥させた後に４００℃で焼成して界面活性剤の除去並びに酸化亜鉛骨格の結晶化を行った。 A transparent thin film of zinc oxide having a large pore nanospace was synthesized using PS 960 -b-PEO 3400 . PS 960 -b-PEO 3400 (0.08 g) was completely dissolved in a THF / ethanol (11.76 mL) mixed solvent having a volume ratio of 4: 1. Next, a transparent precursor solution was prepared by mixing a transparent solution prepared from anhydrous zinc acetate (0.087 g) with a surfactant solution under acidic conditions of hydrochloric acid. A film was formed by spin-coating the obtained solution on a glass substrate, completely dried, and then baked at 400 ° C. to remove the surfactant and crystallize the zinc oxide skeleton.
　酸化チタンや酸化スズの場合と同様に、得られた薄膜のＳＥＭ観察から大孔径ナノ空間が薄膜全体に存在していることが確認できた。透明薄膜のＸＲＤ測定から、酸化亜鉛骨格が十分に結晶化していることが確認できた。無水酢酸亜鉛の代りに無水塩化亜鉛を用いた場合にも、大孔径ナノ空間を有する透明薄膜を得ることができた。 As in the case of titanium oxide or tin oxide, it was confirmed by SEM observation of the obtained thin film that a large pore nanospace was present in the entire thin film. From the XRD measurement of the transparent thin film, it was confirmed that the zinc oxide skeleton was sufficiently crystallized. Even when anhydrous zinc chloride was used instead of anhydrous zinc acetate, a transparent thin film having a large pore nanospace could be obtained.
　大孔径ナノ空間を有する遷移金属酸化物の透明薄膜表面への生体関連色素分子の吸着実験を行った。 Experiments on the adsorption of biologically relevant dye molecules on the transparent thin film surface of transition metal oxides with large pore nanospaces were conducted.
　０．１μｍのシトクロムｃ（以下、Ｃｙ－ｃと略称する）の水溶液を調製し、大孔径ナノ空間を有する酸化チタンの透明薄膜を浸漬して吸着実験を行った。シトクロムは共有結合したヘム基を持つ色素タンパクであり、紫外可視分光測定（ＵＶ－Ｖｉｓ）で４１０ｎｍ付近にヘム基に由来するソーレー帯吸収が観察されるため、その吸収ピークの減少からＣｙ－ｃの吸着挙動を追跡し、初期濃度との変化から吸着量を算出した。吸着実験開始から１２０分経過するとスペクトルの変化がほとんど観察されなくなるため、次に吸着実験後の薄膜を純水中に再度浸漬して、Ｃｙ－ｃの脱離挙動を追跡した。 An adsorption experiment was conducted by preparing an aqueous solution of 0.1 μm cytochrome c (hereinafter abbreviated as Cy-c) and immersing a transparent thin film of titanium oxide having a large pore nanospace. Cytochrome is a chromoprotein with a covalently bonded heme group, and the Soret band absorption derived from the heme group is observed at around 410 nm by ultraviolet-visible spectroscopy (UV-Vis). The adsorption behavior was monitored, and the adsorption amount was calculated from the change from the initial concentration. Since almost no change in the spectrum was observed after 120 minutes from the start of the adsorption experiment, the thin film after the adsorption experiment was immersed again in pure water, and the desorption behavior of Cy-c was followed.
　実施例１で調製した透明な前駆溶液を、スピンコート速度を３０００ｒｐｍで成膜し、４００℃で焼成した大孔径ナノ空間を有する酸化チタンの透明薄膜の表面へのＣｙ－ｃの吸着挙動を図５（ａ）に、脱離挙動を図５（ｂ）に示す。透明薄膜を浸漬すると、時間の経過とともにＣｙ－ｃが吸着している様子が確認でき、吸着実験開始から１２０分経過するとスペクトルの変化がほぼ定常状態に達した。 The adsorption behavior of Cy-c on the surface of a transparent thin film of titanium oxide having a large pore size nanospace obtained by depositing the transparent precursor solution prepared in Example 1 at a spin coating speed of 3000 rpm and firing at 400 ° C. FIG. 5 (a) shows the desorption behavior in FIG. 5 (b). When the transparent thin film was immersed, it was confirmed that Cy-c was adsorbed over time, and after 120 minutes from the start of the adsorption experiment, the change in the spectrum reached a nearly steady state.
　脱離挙動のスペクトル変化を示す図５（ｂ）は縦軸のスケールを１５倍に拡大しているが、Ｃｙ－ｃの脱離がほとんど観察されなかった。このことは、酸化チタン表面にＣｙ－ｃが強く固定化していることを示している。 In FIG. 5 (b) showing the spectrum change of the desorption behavior, the scale of the vertical axis is enlarged 15 times, but Cy-c desorption was hardly observed. This indicates that Cy-c is strongly immobilized on the titanium oxide surface.
　図６に、２５０～６００℃の異なる焼成温度で合成した大孔径ナノ空間を有する酸化チタンの透明薄膜の表面へのＣｙ－ｃの吸着量の変化を示す。このＸＲＤ測定により、焼成温度を高くするとアナターゼ相が生成して結晶性が向上することが確認された。焼成温度を高くすると、比表面積はほとんど変わらないのに、Ｃｙ－ｃの吸着量が増大した。従って、酸化チタン骨格の結晶性もＣｙ－ｃの吸着量に影響を与えていることがわかる。 FIG. 6 shows changes in the amount of Cy-c adsorbed on the surface of a transparent thin film of titanium oxide having a large pore nanospace synthesized at different firing temperatures of 250 to 600 ° C. From this XRD measurement, it was confirmed that when the firing temperature was increased, an anatase phase was generated and the crystallinity was improved. Increasing the calcination temperature increased the amount of Cy-c adsorbed, although the specific surface area hardly changed. Therefore, it can be seen that the crystallinity of the titanium oxide skeleton also affects the amount of Cy-c adsorption.
　比較として、各種酸化チタンの多孔体薄膜の表面へのＣｙ－ｃの吸着量の比較を行った。その結果を図７に示す。メソ多孔体薄膜（Ｆ１２７と表記する）、エマルジョン由来のマクロ孔を含むメソ多孔体薄膜（Ｆ１２７＋ＴＩＰＢｚと表記する）、ＰＳビーズを添加して導入したマクロ孔を含め（Ｆ１２７＋ＰＳ（ｘ）と表記する）（ｘは５重量％ＰＳ水溶液添加量）メソ多孔体薄膜並びに酸化チタンのナノ粒子の体積膜（Ｐ２５　ｆｉｌｍと表記する）と比較して、比表面積が小さいにも関わらず、大孔径ナノ空間を有する酸化チタンの透明薄膜の表面へのＣｙ－ｃの吸着量が圧倒的に大きな値を示した。このことは、メソ多孔体薄膜内にはＣｙ－ｃ（１０ｎｍ程度の分子径）が導入できず、Ｃｙ－ｃの吸着が表面近傍に制限されたためである。従って、マクロ孔のみからなり大きな連結孔が大量に存在している本発明の大孔径ナノ空間を有する酸化チタンの透明薄膜がＣｙ－ｃのような比較的大きな分子に対して優れた吸着特性を示したと解釈できる。 As a comparison, the amount of Cy-c adsorbed on the surface of various titanium oxide porous thin films was compared. The result is shown in FIG. Includes mesoporous thin film (denoted as F127), mesoporous thin film containing macropores derived from emulsion (denoted as F127 + TIPBz), and macropores introduced by adding PS beads (denoted as F127 + PS (x)) (X is the addition amount of 5 wt% PS aqueous solution) Compared with the mesoporous thin film and the volume film of nanoparticles of titanium oxide (referred to as P25 film), although the specific surface area is small, the large pore nanospace is The amount of Cy-c adsorbed on the surface of the transparent thin film of titanium oxide having an overwhelmingly large value. This is because Cy-c (molecular diameter of about 10 nm) cannot be introduced into the mesoporous thin film, and the adsorption of Cy-c is limited to the vicinity of the surface. Therefore, the transparent thin film of titanium oxide having large pore nanospaces of the present invention, which is composed of macropores and a large number of large connecting pores, has excellent adsorption characteristics for relatively large molecules such as Cy-c. It can be interpreted as shown.
　実施例２の酸化スズで調製した透明な前駆溶液及び、実施例３の酸化亜鉛で調製した透明な前駆溶媒による、大孔径ナノ空間を有する酸化スズ及び酸化亜鉛の透明薄膜を用いて同様の実験を行った。これによれば、酸化スズを用いた場合にも大量のＣｙ－ｃが吸着することが確認された（図８参照）。ここから、大孔径ナノ空間の存在がＣｙ－ｃの吸着には重要であり、薄膜内部にまで吸着していることが推測することができる。シトクロムはタンパク質がヘム基を取り囲むような構造しているため、酸化チタンや酸化スズ等の遷移金属酸化物骨格の表面にはタンパク質が相互作用しているものと考えられる。従って、本発明の大孔径ナノ空間を有する遷移金属酸化物は、シトクロムだけでなく、塩基配列構造を有するＤＮＡやタンパク質等の生体関連分子の吸着分離材として極めて高い性能を示すと考えられる。 A similar experiment using a transparent thin film of tin oxide and zinc oxide having a large pore nanospace by the transparent precursor solution prepared with tin oxide of Example 2 and the transparent precursor solvent prepared with zinc oxide of Example 3 Went. According to this, it was confirmed that a large amount of Cy-c was adsorbed even when tin oxide was used (see FIG. 8). From this, it can be inferred that the presence of the large pore nanospace is important for the adsorption of Cy-c, and is adsorbed even inside the thin film. Since cytochrome is structured so that the protein surrounds the heme group, it is considered that the protein interacts with the surface of the transition metal oxide skeleton such as titanium oxide or tin oxide. Therefore, the transition metal oxide having a large pore nanospace of the present invention is considered to exhibit extremely high performance as an adsorbing / separating material for biologically related molecules such as DNA and proteins having a base sequence structure as well as cytochrome.
　実施例１で調製した透明な前駆溶液による大孔径ナノ空間を有する遷移金属酸化物の透明薄膜をフッ素ドープ酸化スズ（ＦＴＯ）基板上へ成膜し、ＤＮＡの吸着実験を行った。ＤＮＡ１分子に対して１分子の色素（シトクロム）を標識して、その標識色素からの蛍光発光の強度測定からＤＮＡ吸着量を算出した。その分子をＣｙ５－ｓｓＤＮＡ（塩基配列：ＧＣＧＧＣＡＴＧＡＡＣＣＴＧＡＧＧＣＣＣＡＴＣＣＴ）と表記する。シトクロムのヘム基内部には金属中心が鉄（Ｆｅ）のポルフィリン環構造が存在しており、生体内では電子伝達タンパク質として機能するが、光エネルギーを捕捉するための色素分子としてポルフィリン環構造が利用されている。 A transparent thin film of transition metal oxide having a large pore nanospace by the transparent precursor solution prepared in Example 1 was formed on a fluorine-doped tin oxide (FTO) substrate, and a DNA adsorption experiment was performed. One molecule of dye (cytochrome) was labeled with respect to one DNA molecule, and the amount of adsorbed DNA was calculated from intensity measurement of fluorescence emission from the labeled dye. The molecule is expressed as Cy5-ssDNA (base sequence: GCGGCATGAACCTGAGGCCCCATCCT). Inside the heme group of cytochrome, there is a porphyrin ring structure with a metal center of iron (Fe), which functions as an electron transfer protein in vivo, but the porphyrin ring structure is used as a dye molecule for capturing light energy. Has been.
　具体的には、水に溶かしたｓｓＤＮＡを９５℃で１０分間加熱して変性させ、薄膜に５ｍＬをスポット滴下して、９５℃で１０分間保持した。薄膜を０．２％ドデシル硫酸ナトリウム水溶液で洗浄、純水での濯ぎ、沸騰水中２分間浸漬、エタノール中４℃で２分間浸漬の順で基板を洗浄処理して余分な生体分子を除去した。 Specifically, ssDNA dissolved in water was denatured by heating at 95 ° C. for 10 minutes, and 5 mL was spot-dropped on the thin film and held at 95 ° C. for 10 minutes. The thin film was washed with 0.2% sodium dodecyl sulfate aqueous solution, rinsed with pure water, immersed in boiling water for 2 minutes, and then immersed in ethanol at 4 ° C. for 2 minutes to remove excess biomolecules.
　色素増感太陽電池の動作原理を利用して、光で励起して吸着している標識色素（Ｃｙ５）から発生する電子（光電流）が検出されるかを検討した。Ｃｙ５が吸着してない状態も評価するために、標識色素のないＤＮＡ（塩基配列：ＴＴＧＡＧＣＡＡＧＴＴＣＡＧＣＣＴＧＧＴＴＡＡＧ）の吸着実験も同様に行った。 Using the principle of operation of the dye-sensitized solar cell, it was examined whether electrons (photocurrent) generated from the labeled dye (Cy5) excited by light and adsorbed were detected. In order to evaluate the state in which Cy5 was not adsorbed, an adsorption experiment of DNA without a labeling dye (base sequence: TTGAGCAAGTTCAGCCTGGTTAG) was performed in the same manner.
　実施例４に示したＣｙ－ｃの吸着、脱離挙動の調査では、水溶液からの吸着並びに水中への脱離の挙動からＣｙ－ｃが酸化チタン並びに酸化スズの表面と強く相互作用していることを示した。実施例５では、Ｃｙ５－ｓｓＤＮＡを薄膜表面に固定化後、徹底的に基板を洗浄処理して余分な生体分子の除去行っているが、それにも拘らずＣｙ５－ｓｓＤＮＡは薄膜表面に固定化されていたことから、極めて強く固定化されていることが確認された。 In the investigation of the adsorption and desorption behavior of Cy-c shown in Example 4, Cy-c strongly interacts with the surface of titanium oxide and tin oxide from the behavior of adsorption from aqueous solution and desorption into water. Showed that. In Example 5, Cy5-ssDNA was immobilized on the thin film surface, and then the substrate was thoroughly washed to remove excess biomolecules. Nevertheless, Cy5-ssDNA was immobilized on the thin film surface. Therefore, it was confirmed that it was extremely strongly immobilized.
　各種酸化チタンの多孔体薄膜表面へのＣｙ５－ｓｓＤＮＡの吸着量の比較を行った。その結果を図９に示す。４００℃焼成して骨格を結晶（アナターゼ）化したＦ１２７及びＦ１２７＋ＰＳ（ｘ）と比較しても、本発明の大孔径ナノ空間を有する酸化チタン薄膜（３０００ｒｐｍで成膜した場合を表示）が極めて高い吸着性能を示していることがわかる。Ｃｙ５－ｓｓＤＮＡの分子サイズが大きいために、Ｆ１２７及びＦ１２７＋ＰＳ（ｘ）の場合は薄膜内部までＣｙ５－ｓｓＤＮＡの吸着ができないことを表している。標識色素が無い場合には当然蛍光発光が観察されないが、Ｃｙ５－ｓｓＤＮＡを吸着させると蛍光発光が確認でき、濃度を高くするとより多くのＣｙ５－ｓｓＤＮＡが吸着する様子が観察された。 Comparison of the amount of Cy5-ssDNA adsorbed on the surface of various titanium oxide porous thin films was performed. The result is shown in FIG. Compared with F127 and F127 + PS (x) whose skeleton is crystallized (anatase) by baking at 400 ° C., the titanium oxide thin film having a large pore nanospace according to the present invention (shown when formed at 3000 rpm) is extremely high. It turns out that the adsorption performance is shown. Since the molecular size of Cy5-ssDNA is large, F127 and F127 + PS (x) indicate that Cy5-ssDNA cannot be adsorbed to the inside of the thin film. In the absence of the labeling dye, naturally no fluorescence emission was observed, but when Cy5-ssDNA was adsorbed, fluorescence emission could be confirmed, and when the concentration was increased, more Cy5-ssDNA was adsorbed.
　次に、光で励起して吸着しているＣｙ５から発生する電子（光電流）が検出されるかを確認した。図１０に示すように、１２０ｍＷという強い光で励起したにも関わらず、Ｆ１２７及びＦ１２７＋ＰＳ（ｘ）では極微量の光電流しか検出できなかった。一方、本発明の大孔径ナノ空間を有する酸化チタン薄膜（３０００ｒｐｍで成膜した場合を表示）は非常に高い電流値を示している。図１１に示すように、光源を６ｍＷと非常に弱いものに変えても、励起色素からの光電流を十分に検出することができた。即ち、各種色素増感の原理を利用した太陽電池等、色素増感型デバイスの高感度電極として極めて有望であることが確認された。 Next, it was confirmed whether electrons (photocurrent) generated from Cy5 excited by light and adsorbed were detected. As shown in FIG. 10, although it was excited by a strong light of 120 mW, only a very small amount of photocurrent could be detected with F127 and F127 + PS (x). On the other hand, the titanium oxide thin film (shown when it is formed at 3000 rpm) having a large pore nanospace of the present invention shows a very high current value. As shown in FIG. 11, even when the light source was changed to a very weak one of 6 mW, the photocurrent from the excitation dye could be sufficiently detected. That is, it was confirmed that the present invention is extremely promising as a high-sensitivity electrode for dye-sensitized devices such as solar cells using various dye-sensitized principles.
　また、４５０℃焼成して骨格を結晶化した大孔径ナノ空間を有する酸化スズ薄膜表面にもＣｙ５－ｓｓＤＮＡが吸着することが確認された。４００℃焼成して骨格を結晶化した大孔径ナノ空間を有する酸化チタン薄膜の場合よりもＣｙ５－ｓｓＤＮＡ吸着量は１桁少なかったが、１２０ｍＷの光で励起すると電流値が飽和してしまうほどであり、光源を６ｍＷと非常に弱いものにすると光電流と色素吸着量の間に良好な関係が見られ、酸化チタン薄膜よりも大きな電流値を示した。 It was also confirmed that Cy5-ssDNA was adsorbed on the surface of the tin oxide thin film having a large pore nanospace that was baked at 450 ° C. to crystallize the skeleton. The amount of Cy5-ssDNA adsorbed was an order of magnitude less than that of a titanium oxide thin film having a large pore nanospace that was baked at 400 ° C. to crystallize the skeleton. However, when excited with 120 mW light, the current value was saturated. There was a good relationship between the photocurrent and the amount of dye adsorbed when the light source was very weak, 6 mW, indicating a larger current value than the titanium oxide thin film.
　実施例１で調製した透明な前駆溶液による大孔径ナノ空間を有する遷移金属酸化物の透明薄膜をＦＴＯ基板上へ成膜し、タンパク質（Ａｎｔｉ－ＡＦＰ抗体ＮＢ０－１３、ＡＦＰ：ａｌｐｈａ－ｆｅｔｏ－ｐｒｏｔｅｉｎ、日本バイオテスト）の吸着実験を行った。ＮＢ０－１３１分子に対して１分子の色素（Ｃｙ５）を標識した分子をＣｙ５－ＮＢ０－１３と表記し、その標識色素からの蛍光発光の強度測定からタンパク質の吸着量を算出した。吸着しているＣｙ５から発生する光電流が検出されるかについても確認した。 A transparent thin film of a transition metal oxide having a large pore nanospace with the transparent precursor solution prepared in Example 1 was formed on an FTO substrate, and proteins (Anti-AFP antibody NB0-13, AFP: alpha-feto-protein) , Japan Biotest) adsorption experiment. A molecule in which one molecule of dye (Cy5) was labeled with respect to NB0-131 molecule was expressed as Cy5-NB0-13, and the amount of protein adsorbed was calculated from the measurement of the intensity of fluorescence emitted from the labeled dye. It was also confirmed whether photocurrent generated from adsorbed Cy5 was detected.
　さらに、抗原抗体反応を利用したタンパク質の検出を行った。ＰＳＡ（Ｐｒｏｓｔａｔｅ　Ｓｐｅｃｉｆｉｃ　Ａｎｔｉｇｅｎ）抗体（ＸＧ－６９、ｇｏａｔ：Ｆｉｔｚｇｅｒａｌｄ　Ｉｎｄｕｓｔｒｉｅｓ　Ｉｎｔｅｒｎａｔｉｏｎａｌ，　Ｉｎｃ．）を１次抗体として固定化し、２次抗体にはタンパク質（Ａｎｔｉ－ＰＳＡ　ｍｏｎｏｃｌｏｎａｌ抗体：５Ａ６、ｍｏｕｓｅ：Ａｎｔｉｂｏｄｉｅｓ－Ｏｎｌｉｎｅ　ＧｍｂＨ）を用いた。この場合、５Ａ６１分子に対して１分子のＣｙ５を標識して（Ｃｙ５－５Ａ６）、その標識色素からの蛍光発光の強度測定並びに電流値測定から、タンパク質の吸着並びに光電流による検出が可能であるかをそれぞれ調査した。なお、タンパク質の蛍光修飾は全てＣｙ５　ｍＡｂ　ｌａｂｅｌｌｉｎｇ　ｋｉｔ（ＰＡ３５００１、ＧＥ　Ｈｅａｌｔｈ　Ｃａｒｅ）を用い、付属マニュアルに従って行った。 Furthermore, the protein was detected using the antigen-antibody reaction. PSA (Prostate Specific Antigen) antibody (XG-69, goat: Fitzgerald Industries International, Inc.) was immobilized as the primary antibody, and the secondary antibody was a protein (Anti-PSA monoclonal antibody: 5A6, neutral: 5A6-mouseGoneBoth ) Was used. In this case, one molecule of Cy5 is labeled with respect to 5A61 molecule (Cy5-5A6), and it is possible to detect protein adsorption and photocurrent from intensity measurement and current value measurement of fluorescence emission from the labeled dye. Each was investigated. In addition, all the fluorescence modification of protein was performed according to the attached manual using Cy5 mAb labeling kit (PA35001, GE Health Care).
　図１２からもわかるように、ＸＧ－６９の濃度を濃くすると蛍光値が大きくなり、４００℃焼成した大孔径ナノ空間を有する酸化チタン薄膜表面にＡｎｔｉ－ＡＦＰ抗体が吸着することが確認できた。４５０℃焼成した大孔径ナノ空間を有する酸化スズ薄膜でも同様な結果が得られた。図１３に示すように、吸着しているＣｙ５から発生する光電流も検出され、色素吸着量と良好な相関関係が確認された。 As can be seen from FIG. 12, when the concentration of XG-69 was increased, the fluorescence value increased, and it was confirmed that the Anti-AFP antibody was adsorbed on the surface of the titanium oxide thin film having a large pore nanospace baked at 400 ° C. Similar results were obtained with a tin oxide thin film having a large pore size nanospace baked at 450 ° C. As shown in FIG. 13, a photocurrent generated from adsorbed Cy5 was also detected, and a good correlation with the dye adsorption amount was confirmed.
　４００℃焼成した大孔径ナノ空間を有する酸化チタン薄膜表面で抗原抗体反応が進行している様子が蛍光測定からは確認できたが、光電流は検出されなかった。一方、図１４に示すように、４５０℃焼成した大孔径ナノ空間を有する酸化スズ薄膜でも、蛍光測定から抗原抗体反応が進行していることが確認できた。しかも、図１５に示すように、光電流測定の結果も蛍光値と良好な相関が確認でき、酸化スズ薄膜の場合には、色素増感太陽電池の原理を利用した光電流の検出が可能であった。 It was confirmed from the fluorescence measurement that the antigen-antibody reaction was proceeding on the surface of the titanium oxide thin film having a large pore nanospace baked at 400 ° C., but no photocurrent was detected. On the other hand, as shown in FIG. 14, it was confirmed from the fluorescence measurement that the antigen-antibody reaction was progressing even in the tin oxide thin film having a large pore size nanospace baked at 450 ° C. Moreover, as shown in FIG. 15, the photocurrent measurement result also shows a good correlation with the fluorescence value, and in the case of a tin oxide thin film, photocurrent detection using the principle of a dye-sensitized solar cell is possible. there were.

Claims (12)

  1. 　親水的な役割を果たすポリオキシエチレンユニットと、疎水的な役割を果たす重合数が３００～４０００の範囲内のポリスチレンユニットのブロック共重合体から構成される界面活性剤と、チタン、スズ又は亜鉛の金属塩及び金属アルコキシドの一種以上を無機原料とした遷移金属酸化物の前駆体を混合して成膜した後、界面活性剤を除去することを特徴とする大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の製造方法。 A surfactant composed of a polyoxyethylene unit that plays a hydrophilic role, a block copolymer of polystyrene units that play a hydrophobic role in the range of 300 to 4000, and titanium, tin, or zinc A transition metal oxide having a large pore size nanospace, characterized by removing a surfactant after mixing a transition metal oxide precursor using at least one of a metal salt and a metal alkoxide as an inorganic raw material Manufacturing method of transparent thin film.
  2. 　透明薄膜の構造が、界面活性剤の自己集合によって規定される規則的、又は不規則的な球状空間の集合であることを特徴とする請求項１に記載の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の製造方法。 The transition metal oxide having a large pore size nanospace according to claim 1, wherein the structure of the transparent thin film is a collection of regular or irregular spherical spaces defined by self-assembly of a surfactant. Method for manufacturing transparent thin film.
  3. 　界面活性剤の自己集合によって規定される大孔径ナノ空間の直径が３０～１５０ｎｍの範囲内であることを特徴とする請求項２に記載の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の製造方法。 3. The transition metal oxide transparent thin film having a large pore nanospace according to claim 2, wherein the diameter of the large pore nanospace defined by the self-assembly of the surfactant is in the range of 30 to 150 nm. Production method.
  4. 　大孔径ナノ空間が、１０ｎｍより大きい孔によって連結されることを特徴とする請求項１から３のいずれかに記載の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の製造方法。 The method for producing a transparent thin film of transition metal oxide having a large pore size nanospace according to any one of claims 1 to 3, wherein the large pore size nanospace is connected by pores larger than 10 nm.
  5. 　透明薄膜の主成分が、酸化チタン、酸化スズ又は酸化亜鉛であって、非晶質構造、結晶構造又はその中間相を有することを特徴とする請求項１から４のいずれかに記載の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の製造方法。 The main component of the transparent thin film is titanium oxide, tin oxide, or zinc oxide, and has an amorphous structure, a crystal structure, or an intermediate phase thereof. A method for producing a transparent thin film of a transition metal oxide having a nanospace.
  6. 　透明薄膜を、高温で界面活性剤を除去する過程で結晶化させることを特徴とする請求項１から５のいずれかに記載の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の製造方法。 6. The method for producing a transparent thin film of transition metal oxide having a large pore size nanospace according to claim 1, wherein the transparent thin film is crystallized in the process of removing the surfactant at a high temperature.
  7. 　請求項１から６のいずれかに記載の方法によって製造された透明薄膜であって、界面活性剤の自己集合が規定する球状の大孔径ナノ空間が規則的又は不規則に集合してなることを特徴とする大孔径ナノ空間を有する遷移金属酸化物の透明薄膜。 A transparent thin film produced by the method according to any one of claims 1 to 6, wherein the spherical large pore nanospace defined by the self-assembly of the surfactant is regularly or irregularly assembled. A transparent thin film of transition metal oxide having a characteristic large pore nanospace.
  8. 　大孔径ナノ空間の直径が３０～１５０ｎｍであることを特徴とする請求項７に記載の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜。 The transparent thin film of transition metal oxide having a large pore size nanospace according to claim 7, wherein the diameter of the large pore size nanospace is 30 to 150 nm.
  9. 　大孔径ナノ空間が、直径が１０ｎｍより大きな孔によって連結してなることを特徴とする請求項７又は８に記載の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜。 9. The transparent thin film of transition metal oxide having a large pore size nanospace according to claim 7 or 8, wherein the large pore size nanospace is connected by pores having a diameter larger than 10 nm.
  10. 　透明薄膜が、非晶質の酸化チタン、酸化スズ又は酸化亜鉛から選択される１種以上から構成されていることを特徴とする請求項７から９のいずれかに記載の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜。 The transparent thin film is composed of one or more selected from amorphous titanium oxide, tin oxide, or zinc oxide, and has a large pore nanospace according to any one of claims 7 to 9 Transparent thin film of transition metal oxide.
  11. 　請求項７から１０のいずれかに記載の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜からなることを特徴とする生体関連分子の吸着分離材。 A bio-related molecule adsorption / separation material comprising a transparent thin film of a transition metal oxide having a large pore nanospace according to any one of claims 7 to 10.
  12. 　請求項７から１０のいずれかに記載の大孔径ナノ空間を有する遷移金属酸化物の透明薄膜の大孔径ナノ空間に機能性色素分子を固定化したことを特徴とする色素増感型デバイス電極。 A dye-sensitized device electrode, wherein functional dye molecules are immobilized in a large-pore nanospace of a transparent thin film of transition metal oxide having a large-pore nanospace according to any one of claims 7 to 10.
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