JP3078603B2 - Method for producing metal oxide thin film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a multilayer porous metal oxide thin film having a structure controlled at a molecular level.

[0002]

2. Description of the Related Art A metal oxide thin film formed by the sol-gel method is described in "Sol-Gel Method Science" (published by Agne Shofusha in 1988, by Mio Sakuhana), pp. 85-153. In addition to physical properties, production methods and usage forms are introduced. The metal alkoxide solution to be used is prepared by adding a target metal oxide to a solvent such as alcohol, water, acid and ammonia. When a metal oxide thin film is formed by a sol-gel method, the volume is reduced due to a crosslinking reaction due to evaporation of a solvent and generation of a methanoxane bond (MOM) during the formation of the thin film, so that cracks are easily generated. Also, it is difficult to obtain a thin film having a uniform structure and thickness. In addition, because of its extremely high hydrolyzability, precipitation may occur in the solution.

Further, since a substrate or a supporting film is used, the substrate or the like is required to have adhesion between the coating film and the substrate and mechanical strength to withstand volume shrinkage during film formation. The material is restricted. In addition, when the thickness of the coating film is large, it is 10 to 20 μm, and when it is thin, it is 0.1 μm.
The limit is about 1 μm. Such a thick film cannot be a thin film whose structure is controlled at the molecular level.

[0004] The metal oxide thin film produced by the sol-gel method is a three-dimensionally crosslinked body, and therefore has a pore diameter of 10 to 20.
It is about 0 Å and has an amorphous pore structure. It is difficult to further increase the pore diameter, and therefore it is not suitable as a carrier for a catalyst or the like.
Further, the orientation of the surface active group cannot be controlled.

As described above, in the conventional sol-gel method, it is difficult to control the thickness, the pore structure, the orientation of surface active groups, and the like of the metal oxide thin film at the molecular level.

As a means for preventing these defects, a method of adding an organic solvent such as formamide, dimethylformamide or the like as a drying control agent has been adopted in the synthesis of a bulk product. However, this method is limited to producing a bulk body, and it is considered impossible to produce a film-like thin film by a sol-gel method. For example, in order to prevent cracking of the thin film, even when a drying control agent such as an organic solvent is added, when the developing solution is water, no matter what hydrophilic organic solvent is used, There is a limit.
For this reason, it is not enough to exhibit the effect as a drying control agent, and it is impossible to completely suppress the occurrence of cracks.

Therefore, in order to improve the conventional sol-gel method, a developing solution containing an amphiphilic compound having polar groups and hydrophobic groups added to both ends of a molecule and a metal alkoxide is prepared. After developing on a substrate, a thin film containing an amphiphilic compound and a metal alkoxysilane substance as a thin film precursor is prepared by removing the solvent from the composite film formed on the substrate. -1314
No. 78. The obtained thin film has a metal-alkoxysilane substance distributed using the molecular assembly of the amphipathic compound as a template. It becomes a metal oxide thin film. In addition, it is introduced that a thin film is modified by promoting a hydrolysis polycondensation reaction such as M (OR) _n and M (OH) _n from the composite film from which the solvent has been removed.

[0008]

In this method, an aqueous developing solution can be used because the alkoxysilane has a lower hydrolyzability than other metal alkoxides. However, when a highly hydrolyzable metal alkoxide is used as a thin film precursor, precipitation tends to occur during preparation of the developing solution. In this respect, the method proposed above is not suitable for producing a metal oxide thin film other than a polysiloxane film.

Further, a molecular assembly necessary for obtaining a thin film whose structure is controlled at a molecular level is formed only in an aqueous solution, not in a non-aqueous solvent. for that reason,
Metal alkoxides as thin film precursors are also extremely unstable, having a high hydrolysis rate and reacting to moisture in the air. In addition, it is difficult to manufacture a thin film incorporating Ti, Zr, Sn and the like, and the type of the obtained thin film is restricted. Furthermore, since the hydrolysis polycondensation reaction of the metal alkoxide proceeds easily in the presence of a large amount of water,
It is also difficult to control the degree of polycondensation.

As a method of solving such a problem,
There is a method proposed in Japanese Patent Application No. 3-68047. In this method, a method for producing a thin film having a structure controlled at a molecular level by utilizing an aggregation state of an amphipathic compound present in a solvent includes an amphipathic compound and a metal alkoxide as a thin film precursor. By preparing the developing solution with a non-aqueous solvent, it is possible to prevent precipitation of metal alkoxide during the developing solution preparation, and to further suppress the occurrence of cracks when forming a film from the prepared developing solution by the developing method. It is possible to obtain.

That is, a developing solution containing a metal alkoxide and an amphipathic compound having a fluorocarbon chain, a group having no affinity for an organic solvent, and a polar group loaded on both ends of a molecule is prepared in a non-aqueous solvent. After the developing solution is spread on the substrate surface, the solvent is removed from the composite thin film formed on the substrate to obtain a metal oxide thin film. However, according to the newly proposed method, the metal alkoxide M
When the kind of (OR) _n and the amount of addition are extremely small, a uniform thin film may not be obtained. For example, Cu (O
CH ₃ ) ₂ , Ca (OCH ₃ ) ₂ , Ba (OC ₂ H ₅ ) ₂ , Z
In the case of metal alkoxides having low functionality such as n (OC ₂ H ₅ ) ₂ , even if it is intended to obtain a single oxide thin film, crosslinking proceeds only one-dimensionally or two-dimensionally, making it difficult to form a thin film. There are cases.

In the case of obtaining a multi-layered metal oxide thin film of an ultra-thin film, a target ultra-thin film can be obtained by minimizing the amount of metal alkoxide added. However, it is difficult to form a thin film having self-supporting properties that is easy to handle, and tends to be a brittle metal oxide thin film.

Further, in addition to the metal alkoxide,
If the metal added as the third component does not have an appropriate alkoxide, that is, if it is difficult to dissolve in the solvent to be used or if synthesis is difficult, use In (CH ₃ COCH ₂ CO _{3).
CH 3), Zn (CH 3} COCH 2 COCH 3) 2 or the like of the metal acetylacetonate and _{Pb (CH 3 COO) 2,} Y (C
It is also conceivable to add a metal organic acid salt such as a metal carboxylate such as ₁₇ H ₃₅ COO) ₃ or Ba (HCOO) ₂ to obtain a metal oxide thin film composed of two or more metal elements. However, in such a case, the rate of hydrolysis of alkoxide and acetylacetonate and the like and the degree of cracking after polycondensation are greatly different, so that a uniform ultrathin metal oxide thin film cannot be obtained.

The present invention has been devised in order to solve such a problem. A solution containing a radical polymerizable monomer is used as a developing solution, and the radical polymerizable monomer is polymerized after forming a thin film. By forming a composite thin film containing a three-dimensionally crosslinked ultrathin polymer, cracks may occur due to the brittleness of the ultrathin metal oxide and the difference in crosslink rate from different starting materials. An object of the present invention is to obtain a stable and uniform metal oxide thin film having a self-supporting property by preventing the thin film from being generated.

[0015]

In order to achieve the object, a method for producing a metal oxide thin film of the present invention comprises, at both ends of a molecule, a group having a fluorocarbon chain and having no affinity for an organic solvent and a polar group. A developing solution containing the added amphiphilic compound, metal alkoxide and radical polymerizable monomer is prepared with a non-aqueous solvent, and the developing solution is spread on the substrate surface to prepare an amphiphilic compound containing a radical polymerizable monomer. After preparing the multilayer bilayer, the radical polymerizable monomer is polymerized to form a composite thin film containing a two-dimensionally crosslinked ultrathin polymer.

As in Japanese Patent Application No. 3-68047, a small amount of water can be added to the developing solution in order to actively carry out the partial hydrolysis polycondensation reaction of the metal alkoxide. Alternatively, the amphiphilic compound can be extracted after subjecting the composite thin film from which the solvent has been removed to chemical treatment or thermal treatment for accelerating the decomposition polycondensation reaction.

The amphiphilic compound used in the present invention is a compound having both a polar group and a hydrophobic group in the same molecule. The polar group includes sulfonate, sulfate, ammonium salt, polyamine salt, carboxylate, sulfonyl salt,
Polyols, including phosphates, phosphonates, phosphonium salts, polyethers, alcohols, sulfonium salts, sugar residues, and the like, and combinations of these groups can be used. On the other hand, as a group having no affinity for an organic solvent (hereinafter, referred to as a solvophobic group), an alkyl group containing a fluorocarbon, an alkyl allyl group, an alicyclic group, a condensed polycyclic group, and a combination of these groups may be used. it can.

The amphiphilic compound used in the present invention includes a fluoroalkylcarboxylic acid having 2 to 20 carbon atoms, a perfluoroalkylcarboxylic acid having 7 to 13 carbon atoms,
A fluorine-based surfactant such as propyl-N- (2-hydroxyethyl) perfluorooctanesulfonamide, or a hydrocarbon chain having a higher molecular orientation than a fluorocarbon chain introduced in Japanese Patent Application No. 2-59019 is used. Illustrative are amphiphilic compounds in combination. These amphiphilic compounds form an aggregated state not only in water but also in various solvents, and a thin film having a regular orientation can be obtained by film formation by a development method. In addition, the radical polymerizable monomer can be taken in, and the taken-in radical polymerizable monomer forms a two-dimensionally crosslinked ultrathin layered product,
It is possible to produce a film-shaped metal oxide thin film having more self-supporting properties.

The metal alkoxide serving as a precursor of the metal oxide thin film is represented by a general formula of M (OR) _n . However,
M represents a metal element, R represents an alkyl group, and n represents the oxidation number of the metal element M.

As the metal element M, Ti, Al, Zr,
Si and the like are listed. Examples of the alkoxides of these metal elements M include Ti (iso-OC ₃ H ₇ ) ₄ and Al (is
_{o-OC 3 H 7) 3} , Zr (OCH 3) 4, Si (OCH 3) 4,
Si (OC ₄ H ₉ ) ₄ , Si (OC ₂ H ₅ ) ₄ , Ba (OC ₂ H ₅ )
There are ₂ etc. In addition to these metal alkoxides, Ge, B, Li, Na, Fe, Ga, Mg, P, S
Metal alkoxides such as b, Sn, Ta, V, etc. are used. Regarding other metal alkoxides, any metal alkoxide that can be generally used by the sol-gel method can be used in the production method of the present invention.

[0021] between the metal alkoxide M (OR) _n is subjected to hydrolysis to produce the M (OH) _n group, M (OH) _n mutual dehydration reaction or M (OH) _n and M (OR) _n A polycondensation reaction is carried out by the dealcoholation reaction of
The film is crosslinked by the formation of -OM to form a thin film.

The reaction at this time is represented by the following equation. The hydrolysis _{reaction: M (OR) n + xH} 2 O → M (OH) x (OR) nx + xROH polycondensation :( dehydration) -M-OH + H-O -M → -M-O-M + H 2 O ( dealcoholation ) -M-OH + R-OM->-M-OM-ROH

R in metal alkoxide M (OR) _n
Need to undergo hydrolysis to produce M (OH) _n groups. Specifically, methyl, ethyl, propyl, butyl, acetoxy, acetylacenate and the like are listed as R. In addition to these normal alkoxides, isomers such as secondary butoxide, tertiary butoxide, isobutoxide and the like are also listed.

The metal alkoxide M (OR) _n can be used alone or in combination of two or more.
Further, in order to form a metal oxide thin film, in addition to the metal alkoxide as a precursor, a metal acetylacetonate M
(CH ₃ COCH ₂ COCH ₃ ) _n , metal carboxylate M (RCOO) _{n and the} like can be added in small amounts. Metal acetylacetonate M (CH ₃ COCH ₂ COCH ₃ )
_n is In (CH ₃ COCH ₂ COCH ₃ ), Zn
(CH ₃ COCH ₂ COCH ₃ ), Ti (O-isoC ₃
H ₇ ) ₂ [OC (CH ₃ ) CHCOCH ₃ ] ₂ , Ti (CH
₃ COCH ₂ COCH ₃ ). Further, as the metal carboxylate M (RCOO) _n , Pb (CH ₃ CO ₃ )
O) ₂ , Y (C ₁₇ H ₃₅ COO) ₃ , Ba (HCOO) _{2 and the} like. Furthermore, the present invention is not limited to other alkoxides, metal acetylacetonates, metal carboxylate, etc., and the metal alkoxides having all various alkoxides and all the various metal acetylacetonates, metal carboxylates, etc. Can be used as well.

The radically polymerizable monomer which is added together with the amphiphilic compound and the metal alkoxide to become a developing solution component can be used alone or by copolymerizing a plurality of polyfunctional monomers of the following formula. Note that R in the following equation
Represents CH ₃ or H. A method of preparing a composite thin film containing an ultrathin polymer by polymerizing these radically polymerizable monomers and this monomer is disclosed in Japanese Patent Application No. 1-58885. And preparation methods can also be employed.

[0026]

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[0027]

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A monofunctional monomer or a diluent such as ethylene glycol or glycerin can be mixed with these polyfunctional monomers. The following compounds are exemplified as usable monofunctional monomers.

[0029]

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Since the above-mentioned amphiphilic compound having a fluorocarbon chain in the lyophobic group forms an aggregated state, the developing solution may be alcohols, ethers, ketones, esters, halogenated alkanes having lower polarity than water. , Nitriles, organic acids, organic bases, aromatic hydrocarbons,
Organic solvents such as saturated and unsaturated hydrocarbons can be used. At this time, when the amount of water added to the developing solution is adjusted in consideration of the hydrolyzability of the metal alkoxide and the effect of moisture taken in from the air and the effect of the acidic catalyst of CO ₂ gas, the hydrolysis weight of the metal alkoxide is adjusted. The degree of condensation can be controlled. As a result, it is possible to produce a thin film having a porous or layered structure according to the purpose. Further, a small amount of an acidic substance or a basic substance may be added in order to promote the hydrolysis of the M (OR) _n group.

A developing solution obtained by adding a radical polymerizable monomer and a metal alkoxide to an amphipathic compound is prepared in Japanese Patent Application No. Hei.
Similarly to the method proposed in US Pat. No. 5,885,885, after spreading on a substrate, the solvent is evaporated to prepare a composite thin film containing a radical polymerizable monomer and a metal alkoxide. Then, the radical polymerizable monomer contained in the composite thin film is polymerized by thermal polymerization, photopolymerization, radiation polymerization, or the like, to produce a composite thin film containing a two-dimensionally crosslinked ultrathin polymer. The chemical treatment, thermal treatment, and the like of the composite thin film can be performed under the same conditions as those of the composite thin film prepared from a developing solution containing no radical polymerizable monomer. The composite thin film subjected to the chemical treatment or the thermal treatment becomes a polymer composite metal oxide thin film by extracting an amphiphilic compound.

The substrate on which the developing solution is developed includes a glass plate,
Examples include a quartz plate, a fluoropore, a graphite plate, a silicon plate, a Teflon plate, a dense polymer film, and a porous polymer film. The surface of the substrate may be subjected to a hydrophilic treatment or a hydrophobic treatment depending on the type of the developing solution. For example, it is also effective to hydrophilize a part of the substrate surface and hydrophobize the remaining surface so that the developing solution is spread on a predetermined area on the substrate surface.

The solvent is removed from the developing solution spread on the substrate to form a composite thin film of the amphiphilic compound and the metal alkoxide. The removal of the solvent is preferably carried out gradually in order for the metal alkoxide to be present in accordance with the regularity of the molecular assembly of the amphiphilic compound and to suppress the partial hydrolysis by the moisture in the air. Further, by removing the solvent in a drying container such as a dry box, it is possible to further suppress partial hydrolysis of the metal alkoxide by moisture in the air or CO ₂ gas.

Subsequently, a chemical treatment or a thermal treatment is performed to advance a hydrolysis polycondensation reaction of M (OR) _n or M (OH) _n groups. Examples of the chemical treatment include a treatment using an acidic substance or a basic substance. For example, a treatment in which the composite thin film is directly immersed in a liquid or a solution of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, ammonia, amine, sodium hydroxide, or the like, or a treatment in which the composite thin film is exposed to a vapor of an acidic or basic substance is effective. is there. Further, a method of heat-treating the composite thin film at several hundred degrees Celsius is also effective.

The composite thin film thus produced is obtained by extracting and removing the amphipathic compound with an extractant selected according to the type of the amphipathic compound, thereby obtaining a metal oxide thin film whose structure is controlled at the molecular level. Become.

[0036]

The present inventors have focused on an amphipathic compound having a fluorocarbon chain which forms various molecular structures even in a non-aqueous organic solvent, and formed a regular molecular assembly formed by the amphiphilic compound. When applying the sol-gel method as a molecular template, it is possible to produce a metal oxide thin film having a structure controlled at the molecular level, even with a metal alkoxide having a high hydrolyzability and causing precipitation in an aqueous solvent, In addition, it has been considered that when an extremely thin metal oxide thin film is obtained by these methods, a stable metal oxide thin film can be obtained by adding a radical polymerizable monomer as a binder. Based on this consideration, as a result of intensive research, the present invention has been completed.

It is known that an amphiphilic compound having a polar group and a lyophobic group having a fluorocarbon chain at both ends of a molecule forms a molecular aggregate not only in water but also in an organic solvent. Although the details are described in Japanese Patent Application No. 2-59019, the description is omitted here, but the amphiphile having a lyophobic group in which a hydrophobic fluorocarbon chain and a hydrocarbon chain having a higher molecular orientation are combined. By dissolving or dispersing the active compound in an organic solvent and developing it on an appropriate substrate, a thin film having regular orientation at the molecular level can be obtained.

On the other hand, an amphipathic compound having only a hydrocarbon chain having no fluorocarbon chain in the lyophobic group forms a molecular aggregate when dispersed in water, but disperses in an organic solvent to form a molecular aggregate. Is difficult to form. Since this is described in detail in Japanese Patent Application No. 1-58889, it is omitted here.

By adding a highly hydrolyzable metal alkoxide to a developing solution in which an amphiphilic compound having a fluorocarbon chain is dissolved or dispersed in an organic solvent, a molecule having a regular orientation formed by the amphiphilic compound is obtained. Using the aggregate as a template, the metal alkoxide is fixed in the developing solution. Further, when a metal alkoxide having a partially hydrolyzed polycondensation reaction caused by addition of a small amount of water or the like is added to the developing solution, or a small amount of water is dispersed in the developing solution to prepare the developing solution, the metal alkoxide is prepared. Is hydrolyzed and polycondensed by using a molecular assembly of an amphiphilic compound as a template to form a certain degree of bridge and is immobilized. The preparation method of these methods differs depending on the type of the amphiphilic compound or the metal alkoxide and the amount of addition. Therefore,
By selecting appropriate conditions, it is possible to change the speed and the like of the hydrolysis polycondensation reaction of the metal alkoxide, and to control the structural form of the thin film at the molecular level.

When a composite thin film is prepared from a developing solution to which a radical polymerizable monomer has been added, a polymer formed after the polycondensation reaction acts as a reinforcing material, and a thin film having high self-supporting properties can be obtained. This ultra-thin composite thin film has a high self-supporting property and is easy to handle. This advantage is advantageous when manufacturing an ultrathin metal oxide film in which the amount of metal alkoxide added is extremely small. When the obtained composite thin film is heat-treated at several hundred degrees Celsius, the polymer is incinerated at the same time, and a metal oxide thin film having a fine structure is obtained.

Moreover, since the developing solution is prepared with an organic solvent, not only those which immediately precipitate when added to water,
Metal alkoxide which immediately forms a precipitate even in the air can be easily added to the developing solution. Furthermore, the generation of defects such as cracks due to volume shrinkage due to a cross-linking reaction, which is generally a problem in the sol-gel method, is also suppressed by the organic solvent acting as a drying control agent.

[0042]

The present invention will be described below in detail with reference to examples. Incidentally, the amphiphilic compound used in the present example,
It is a compound represented by the following formulas 1 and 2.

[0043]

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Example 1 After dissolving 20 mM of amphiphilic compound 1 in methanol, a bifunctional monomer represented by the following formula was equimolar to the amphiphilic compound 1, and a bifunctional monomer was used as a polymerization initiator. 2 (mol%) of 4 (2-hydroxyethoxy) phenyl- (2-hydroxyethoxy-2
-Propyl) ketone was mixed and added. Further, a 0.5-fold molar amount of metal alkoxide Ti (O-isoC ₃ H ₇ ) ₄ was added to the amphiphilic compound 1 to prepare a developing solution.

[0045]

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This developing solution is dropped on a glass plate (hereinafter, simply referred to as a glass plate) surrounded by a fluororesin film frame, and placed in a dry box kept at room temperature and a humidity of 5% or less for 2 days. The composite film was obtained by allowing the developing solution to evaporate the organic solvent. Next, the composite membrane was put into a sealed container filled with ammonia vapor, and left at room temperature for one week. Thereafter, ultraviolet rays were irradiated using an ultra-high pressure mercury lamp to crosslink and polymerize the bifunctional monomer.

Further, the composite thin film was put into an electric furnace, heated at a heating rate of 10 ° C./min, and left at 600 ° C. for 10 hours. As a result, a white thin film was obtained. The obtained thin film had a thickness of several μm, had no defects such as cracks, and had a sufficient self-supporting property. Further, it was found from SEM observation that the fine particle aggregate had a fine structure.

On the other hand, a developing solution prepared without adding a polymerizable monomer was developed and processed by the same method. In this case, a white fine powder was formed, and no thin film was produced.

Example 2: 100 mM amphiphilic compound 2
Is dissolved in hexafluorobenzene, and then a bifunctional monomer represented by the following formula is equimolar to the amphipathic compound 2 and 3 mol% of 4
(2-Hydroxyethoxy) phenyl- (2-hydroxyethoxy-2-propyl) ketone was mixed and added. Further, 0.1-fold molar amount of metal alkoxide Ti (O-nC ₄ H ₉ ) ₄ and 0.1-fold molar amount of Ba (OC ₂ H ₅ ) ₂ are also added to amphiphilic compound 2. A developing solution was prepared.

[0050]

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This developing solution was spread on a glass plate, and the solvent was evaporated under the same conditions as in Example 1. Then, ultraviolet rays were irradiated using an ultra-high pressure mercury lamp to cross-link and polymerize the bifunctional monomer. Was. The obtained composite thin film was put into an electric furnace, heated at a rate of 10 ° C./min, and left at 700 ° C. for 30 minutes. As a result, a white translucent thin film was obtained. This thin film had a thickness of 10 μm and had a uniform fine structure of fine particle aggregates as observed by SEM observation.

On the other hand, even if the developing solution prepared without adding the polymerizable monomer was developed by the same method and subjected to a high-temperature treatment, the developing solution became fine powder and no thin film was obtained.

As is apparent from Examples 1 and 2, a metal oxide thin film having a fine structure was produced by using various metal alkoxides as precursors and changing the type of amphiphilic compound used and the production conditions. Was. The obtained thin film changes the microstructure whose structure is controlled at the molecular level in various ways by adjusting the type of amphipathic compound, polymerizable monomer and the like and the manufacturing conditions. Therefore, it has become possible to manufacture an ultra-thin film having a function according to the purpose. Ultra-thin films having predetermined pores, film thicknesses, layered structures, and the like at the molecular level include optical materials, permeable membranes for material separation and adsorption, catalyst carriers, biochemical carriers for immobilized enzymes, and the like. Combustion catalyst carrier, photoelectrochemical membrane, ionic conductor, electronic conductor,
As a material for a superconductor or the like, it can be used for various applications.

[0054]

As described above, in the present invention, the characteristics of an amphiphilic compound which forms a molecular assembly even in an organic solvent are utilized, and the amphiphilic compound is developed when the developing solution is spread on a substrate. A self-supporting property is improved by using a molecular organization body having regular molecular orientation formed from as a template and polymerizable monomer added as a binder to form a stable thin film with excellent handleability. Obtainable. In addition, since the self-supporting property of the thin film is improved by the cross-linking polymerization reaction of the polymerizable monomer, an extremely thin film can be produced by extremely reducing the amount of metal alkoxide, which is a precursor of the metal oxide. Moreover, even a thin film prepared from a developing solution containing a small amount of metal alkoxide has a high orientation and can control the structure at the molecular level, so that a thin film without cracks can be obtained. The thin film thus obtained is used as a high-performance material separation film, various carriers, a conductive film, etc. by utilizing its structural characteristics.

Continuation of the front page (72) Inventor Toyoshi Kunitake 1-19-3 Sakuragaoka, Shimen-cho, Kasuya-gun, Fukuoka Prefecture (56) References JP-A-4-280802 (JP, A) JP-A-4-63120 (JP, A) JP-A-4-63384 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) CA (STN)

Claims (3)

(57) [Claims] 1. A developing solution containing an amphiphilic compound, a metal alkoxide, and a radical polymerizable monomer having a fluorocarbon chain, a group having no affinity for an organic solvent, and a polar group added to both ends of the molecule. Prepared in an aqueous solvent,
After developing the developing solution on the substrate surface to prepare a multilayer bilayer film of the amphipathic compound containing the radically polymerizable monomer, the radically polymerizable monomer is polymerized to form a two-dimensionally crosslinked ultrathin layer. A method for producing a metal oxide thin film, comprising forming a composite thin film containing a polymer. 2. A method for producing a metal oxide thin film, wherein the developing solution according to claim 1 contains water as one component. 3. A method for producing a metal oxide thin film, comprising subjecting a composite thin film containing the ultrathin polymer according to claim 1 to thermal treatment or chemical treatment to remove the ultrathin polymer.