JPH055041A - Production of thin film of metal oxide - Google Patents

Abstract

PURPOSE:To obtain a stable uniform thin film of metal oxide preventing brittleness and cracks, having self-supporting properties by forming a thin film from a radicaly-polymerizable monomer-containing solution, polymerizing the radical- polymerizable monomer and cross-linking in a two-dimensional way to make an ultra-thin film. CONSTITUTION:A developing solution comprising an amphiphatic compound which contains a fluorocarbon chain and a group having no affinity for organic solvents and a polar group added to both ends of the molecule, a metal alkoxide and a radical-polymerizable monomer is prepared in a nonaqueous solvent. The developing solution is extended on the surface of a substrate, a multi-layer bimolecular film of the amphiphatic compound containing the radical- polymerizable monomer is formed and the radical-polymerizable monomer is polymerized to make a complex thin film containing an ultra-thin film layer polymer cross-linked in a two-dimensional way. 2-20C fluoroalkylcarboxylic acid is used as the amphiphatic compound.

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 multilayered and porous metal oxide thin film whose structure is controlled at the molecular level.

[0002]

2. Description of the Related Art A metal oxide thin film formed by the sol-gel method is described in "Science of the sol-gel method" (published by Agne Jofusha, 1988, by Sakuka Sao), pp. 85-153. In addition to physical properties, manufacturing methods and usage patterns are introduced. The metal alkoxide solution used is prepared by adding the target metal oxide to a solvent such as alcohol, water, acid or ammonia. When a metal oxide thin film is produced by the sol-gel method, cracks are likely to occur because volume shrinkage occurs due to a crosslinking reaction due to evaporation of a solvent or formation of a methanoxane bond (MOM) during thin film formation. Moreover, it is difficult to obtain a thin film having a uniform structure and film thickness. Moreover, since it is very hydrolyzable, precipitation may occur in the solution.

Further, since the substrate and the supporting film are used, the adhesiveness between the coating film and the substrate and the mechanical strength to withstand the volume shrinkage during the film formation are required for the substrate and the like. Material is restricted. Moreover, the coating film has a thickness of 10 to 20 μm when it is thick, and a thickness of 0.
The limit is about 1 μm. Such a thick film cannot be a thin film whose structure is controlled at the molecular level.

Since the metal oxide thin film produced by the sol-gel method is a three-dimensional crosslinked body, it has a pore size of 10 to 20.
The pore structure is about 0 angstrom and has an amorphous pore structure. It is difficult to make the pore size larger than this, and therefore it is unsuitable as a carrier for catalysts and the like.
Further, it is not possible to control the orientation of the surface active groups.

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

As a means for preventing these defects, in the synthesis of the bulk body, a method of adding an organic solvent such as formamide or dimethylformamide as a drying control agent has been partially adopted. However, this method is limited to the production of a bulk body, and it is considered impossible to produce a film-shaped thin film by the sol-gel method. For example, in order to prevent cracking of the thin film, even if 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.
Therefore, it does not reach the effect as a drying control agent, and the generation of cracks cannot be completely suppressed.

Therefore, in order to improve the conventional sol-gel method, a developing solution containing an amphipathic compound having a polar group and a hydrophobic group at both ends of a molecule and a metal alkoxide is prepared, and this developing solution is prepared. Japanese Patent Application No. Hei 1 (1999) -109242 discloses that a thin film containing an amphipathic 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 after spreading on the substrate. -1314
Proposed in No. 78. The obtained thin film, in which the metal alkoxysilane substance is distributed using the molecular assembly of the amphipathic compound as a template, has a multi-layered structure and a porous structure in which the structure is controlled at the molecular level when the amphipathic compound is extracted. It becomes a metal oxide thin film. It is also introduced that the thin film is modified by promoting the hydrolytic polycondensation reaction of M (OR) _n , M (OH) _{n and the} like from the composite film from which the solvent has been removed.

[0008]

In this method, since the alkoxysilane has a lower hydrolyzability than other metal alkoxides, an aqueous developing solution can be used. 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 previously proposed method is not suitable for producing a metal oxide thin film other than the polysiloxane film.

Further, the molecular assembly necessary for obtaining a thin film whose structure is controlled at the molecular level is formed only in an aqueous solution and not in a non-aqueous solvent. for that reason,
Metal alkoxide as a thin film precursor is also an extremely unstable substance which has a high hydrolysis rate and reacts with moisture in the air. Moreover, it is difficult to manufacture a thin film that incorporates Ti, Zr, Sn, etc., and the type of thin film obtained is restricted. Furthermore, the hydrolysis polycondensation reaction of metal alkoxide easily proceeds 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 whose structure is controlled at the molecular level by utilizing the aggregated state of amphipathic compounds present in a solvent contains 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 the metal alkoxide from precipitating when the developing solution is prepared, and to prevent 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 an amphipathic compound having a fluorocarbon chain and having no affinity for an organic solvent and a polar group at both ends of the molecule and a metal alkoxide was prepared in a non-aqueous solvent. Then, after the developing solution is spread on the surface of the substrate, the solvent is removed from the composite thin film formed on the substrate to obtain a metal oxide thin film. However, when using the newly proposed method, metal alkoxide M
_If the type and amount of (OR) _n 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
With metal alkoxides having low functionalities such as n (OC ₂ H ₅ ) ₂ , even if one attempts to obtain an oxide thin film by itself, cross-linking proceeds only one-dimensionally or two-dimensionally, and it is difficult to form a thin film. There are cases.

Further, in the case of obtaining a metal oxide thin film having a multi-layered ultra thin film, the target ultra thin film can be obtained by setting the addition amount of metal alkoxide to an extremely small amount. However, it is difficult to form a self-supporting thin film that is easy to handle, and tends to be a brittle metal oxide thin film.

In addition to the metal alkoxide,
If the metal added as the third component does not have a suitable alkoxide, that is, if it is difficult to dissolve in the solvent to be used or if the synthesis is difficult, In (CH ₃ COCH ₂ CO
CH ₃ ), Zn (CH ₃ COCH ₂ COCH ₃ ) _{2 and} other metal acetylacetonates, 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 kinds of metal elements. However, in such a case, since the hydrolysis rate of alkoxide and acetylacetonate or the like, the crack degree after polycondensation, and the like are greatly different, a metal oxide thin film having a uniform ultrathin 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 dimensionally cross-linked ultra-thin film polymer, cracks are caused by the brittleness accompanying the ultra-thinning of metal oxides and the difference in the cross-linking rate derived from different starting materials. It is an object of the present invention to obtain a stable and uniform metal oxide thin film having self-supporting property by preventing the thin film from being generated.

[0015]

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

As in Japanese Patent Application No. 3-68047, a small amount of water can be added to the developing solution in order to positively carry out a partial hydrolysis polycondensation reaction of metal alkoxide. Further, the amphipathic compound can be extracted after subjecting the composite thin film after removing the solvent to a chemical treatment or a thermal treatment for promoting the decomposition polycondensation reaction.

The amphipathic compound used in the present invention is a compound having both a polar group and a hydrophobic group in the same molecule. As the polar group, 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 solvent-phobic group), an alkyl group containing a fluorocarbon, an alkylallyl group, an alicyclic group, a condensed polycyclic group or a combination of these groups may be used. it can.

As the amphipathic compound used in the present invention, fluoroalkylcarboxylic acid having 2 to 20 carbon atoms, perfluoroalkylcarboxylic acid having 7 to 13 carbon atoms, N-
Fluorine-based surfactants such as propyl-N- (2-hydroxyethyl) perfluorooctanesulfonamide and fluorocarbon chains introduced in Japanese Patent Application No. 2-59019 and hydrocarbon chains having a higher molecular orientation are used. A combination of amphipathic compounds is illustrated. These amphipathic 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 the film formation by the expansion method. In addition, a radically polymerizable monomer can be incorporated, and the incorporated radically polymerizable monomer forms a two-dimensionally crosslinked ultrathin layer laminate,
It becomes possible to manufacture a film-shaped metal oxide thin film having more self-supporting properties.

The metal alkoxide serving as the precursor of the metal oxide thin film is represented by the 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 etc. are listed. Examples of 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 is ₂ mag. In addition to these metal alkoxides, Ge, B, Li, Na, Fe, Ga, Mg, P, S
Metallic alkoxides such as b, Sn, Ta and V are used. As for other metal alkoxides, any metal alkoxide generally usable in 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 The polycondensation reaction is carried out by the dealcoholization reaction of
The formation of -OM crosslinks to form a thin film.

The reaction at this time is expressed as follows. 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 the metal alkoxide M (OR) _n
Needs to undergo hydrolysis to form M (OH) _n groups. Specifically, R is methyl, ethyl, propyl, butyl, acetoxy, acetylacenato or the like. In addition to these normal alkoxides, isomers such as secondary butoxide, tertiary butoxide and isobutoxide are also listed.

The metal alkoxide M (OR) _n can be used alone or in combination of two or more kinds.
Further, in order to form a metal oxide thin film, in addition to metal alkoxide serving as a precursor, metal acetylacetonate M
It is also possible to add a small amount of (CH ₃ COCH ₂ COCH ₃ ) _n , metal carboxylate M (RCOO) _n, or the like. 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 ) and the like. The metal carboxylate M (RCOO) _n is Pb (CH ₃ CO
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 carboxylates and the like, and metal alkoxides having all kinds of alkoxides and all kinds of metal acetylacetonates and metal carboxylates are not limited. Can be used as well.

The radical-polymerizable monomer, which is added together with the amphipathic compound and the metal alkoxide to serve as the developing solution component, may be used alone or in a combination of a plurality of polyfunctional monomers of the following formula. Note that R in the following equation
Represents CH ₃ or H. These radical-polymerizable monomers and a method for polymerizing the monomers to prepare a composite thin film containing an ultrathin layer polymer are shown in Japanese Patent Application No. 1-58885, but are not restricted thereto and other monomers And the preparation method can also be adopted.

[0026]

[Chemical 1]

[0027]

[Chemical 2]

It is also possible to mix a monofunctional monomer or a diluent such as ethylene glycol or glycerin with these polyfunctional monomers. The following compounds are exemplified as usable monofunctional monomers.

[0029]

[Chemical 3]

Since the amphipathic compound having a fluorocarbon chain as a lyophobic group forms an aggregated state, as a developing solution, alcohols, ethers, ketones, esters, halogenated alkanes having a polarity lower than that of water are used. , 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 the moisture taken from the air and the acid 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 manufacture a thin film having a structure in which the porosity or the layer shape is changed according to the purpose. Furthermore, a small amount of an acidic substance or a basic substance may be added in order to accelerate the hydrolysis of the M (OR) _n group.

A developing solution obtained by adding a radically polymerizable monomer and a metal alkoxide to an amphipathic compound is disclosed in Japanese Patent Application No.
Similar to the method proposed in 58885, after spreading on a substrate, the solvent is evaporated to prepare a composite thin film containing a radically 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 cross-linked ultrathin layer polymer. The chemical treatment, thermal treatment, etc. of this composite thin film can be carried out under the same conditions as the composite thin film prepared from the developing solution containing no radically polymerizable monomer. The chemically or thermally treated composite thin film becomes a polymer composite metal oxide thin film by extracting the amphipathic compound.

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

The solvent is removed from the developing solution spread on the substrate to form a composite thin film of the amphipathic compound and the metal alkoxide. Since the metal alkoxide is present according to the regularity of the molecular assembly of the amphipathic compound and the partial hydrolysis by the water in the air is suppressed, the solvent is preferably removed gradually. 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 water in the air or CO ₂ gas.

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

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

[0036]

The present inventors focused their attention on an amphipathic compound having a fluorocarbon chain that forms various molecular assemblies even in a non-aqueous organic solvent, and found a regular molecular assembly formed by this amphipathic compound. When applying the sol-gel method as a molecular template, it is possible to produce a metal oxide thin film whose structure is controlled at the molecular level, even with metal alkoxide that is highly hydrolyzable and causes precipitation in an aqueous solvent, Moreover, when obtaining an extremely thin metal oxide thin film by these methods, it was considered that a stable metal oxide thin film can be obtained by adding a radical polymerizable monomer as a binder. As a result of earnest research based on this consideration, the present invention has been completed.

It is known that an amphipathic compound having a polar group and a solvophobic 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. The details are described in Japanese Patent Application No. 2-59019 and thus omitted here, but an amphipathic group having a solvophilic group in which a fluorocarbon chain having a high hydrophobicity and a hydrocarbon chain having a higher molecular orientation are combined. By dissolving or dispersing the organic compound in an organic solvent and developing it on an appropriate substrate, a thin film having a 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 as a lyophobic group forms a molecular aggregate when dispersed in water, but is dispersed in an organic solvent. Is difficult to form. This has been described in detail in Japanese Patent Application No. 1-58889, and will not be described here.

A molecule having an ordered orientation formed by an amphipathic compound by adding a highly hydrolyzable metal alkoxide to a developing solution obtained by dissolving or dispersing an amphipathic compound having a fluorocarbon chain in an organic solvent. The metal alkoxide is fixed in the developing solution using the aggregate as a template. Furthermore, if a metal alkoxide, which has been partially hydrolyzed and polycondensed by adding a small amount of water, is added to the developing solution, or if a small amount of water is dispersed in the developing solution to prepare the developing solution, the metal alkoxide can be prepared. Is immobilized by forming a certain degree of cross-linking by proceeding with a hydrolysis polycondensation reaction using a molecular assembly of an amphipathic compound as a template. In these methods, the preparation method differs depending on the type of the amphipathic compound or the metal alkoxide and the addition amount thereof. Therefore,
By selecting appropriate conditions, it becomes possible to change the speed of the hydrolysis polycondensation reaction of metal alkoxide, etc., and control the structural morphology of the thin film at the molecular level.

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

In addition, since the developing solution is prepared with an organic solvent, not only those which cause precipitation immediately when added to water,
A metal alkoxide that forms a precipitate immediately in air can be easily added to the developing solution. Furthermore, the occurrence of defects such as cracks due to volumetric shrinkage associated with the crosslinking reaction, which is generally a problem in the sol-gel method, is also suppressed by the organic solvent that functions as a drying control agent.

[0042]

EXAMPLES The present invention will be specifically described below with reference to examples. The amphipathic compound used in this example is
It is a compound represented by the following formulas 1-2.

[0043]

[Chemical 4]

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

[0045]

[Chemical 5]

This developing solution was dropped onto a glass plate surrounded by a fluororesin film frame (hereinafter, simply referred to as a glass plate) and kept in a dry box kept at room temperature and having a humidity of 5% or less for 2 days. After standing, the organic solvent in the developing solution was evaporated to obtain a composite film. Then, the composite film was placed in a closed container filled with ammonia vapor and left at room temperature for 1 week. After that, the bifunctional monomer was cross-linked and polymerized by irradiating with ultraviolet rays using an ultra-high pressure mercury lamp.

Further, this composite thin film was placed in an electric furnace, heated at a temperature rising rate of 10 ° C./minute 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 sufficient self-supporting properties. Further, it was found by SEM observation that the fine particle aggregate had a fine structure.

On the other hand, the developing solution prepared without adding the polymerizable monomer was developed and treated by the same method. In this case, a white fine powder was formed and a thin film was not produced.

Example 2: 100 mM amphipathic compound 2
Was dissolved in hexafluorobenzene, and then the bifunctional monomer represented by the following formula was used in an equimolar amount with the amphipathic compound 2, and as a polymerization initiator, 4 mol of 3 mol% based on the bifunctional monomer was used.
(2-Hydroxyethoxy) phenyl- (2-hydroxyethoxy-2-propyl) ketone was mixed and added. Further, 0.1 times molar amount of metal alkoxide Ti (O-nC ₄ H ₉ ) ₄ and 0.1 times molar amount of Ba (OC ₂ H ₅ ) ₂ were added to the amphipathic compound 2. A developing solution was prepared.

[0050]

[Chemical 6]

This developing solution was spread on a glass plate, the solvent was evaporated under the same conditions as in Example 1, and then ultraviolet rays were irradiated using an ultrahigh pressure mercury lamp to crosslink and polymerize the bifunctional monomer. It was The obtained composite thin film was put into an electric furnace, heated at a heating 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.

On the other hand, even when the developing solution prepared without adding the polymerizable monomer was developed by the same method and subjected to high temperature treatment, it became fine powder and a thin film could not be obtained.

As is clear from Examples 1 and 2, by using various metal alkoxides as precursors and changing the kind of the amphipathic compound to be used and the production conditions, a metal oxide thin film having a fine structure was produced. It was The obtained thin film variously changes the fine structure whose structure is controlled at the molecular level by adjusting the types of amphipathic compounds and polymerizable monomers and the manufacturing conditions. Therefore, it has become possible to manufacture an ultrathin film having a function according to the purpose. The ultrathin film having predetermined pores, film thickness, layered structure, etc. at the molecular level is, for example, an optical material, a permeable membrane for substance separation or adsorption, a catalyst carrier, a biochemical carrier for immobilized enzyme, Combustion catalyst carrier, photoelectrochemical film, ionic conductor, electronic conductor,
It can be used for various purposes as a material for a superconductor or the like.

[0054]

As described above, in the present invention, the characteristics of the amphipathic compound that forms a molecular aggregate even in an organic solvent are utilized, and the amphipathic compound is spread when the developing solution is spread on the substrate. By using a molecular assembly having a regular molecular orientation formed from as a template and crosslinking the polymerizable monomer added as a binder, self-supporting property is improved and a stable thin film with excellent handleability is formed. Obtainable. Further, the self-supporting property of the thin film is improved by the cross-linking polymerization reaction of the polymerizable monomer. Therefore, by making the addition amount of the metal alkoxide, which is the precursor of the metal oxide, extremely small, it becomes possible to produce an ultra-thin film. Moreover, even with a thin film prepared from a developing solution containing a small amount of metal alkoxide added, it is possible to obtain a thin film without cracks because the orientation is high and the structure can be controlled at the molecular level. The thin film thus obtained is used as a highly functional substance separation film, various carriers, a conductive film, etc. by utilizing its structural characteristics.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kanji Sakata 304-1, Futsukaichi, Chikushino, Fukuoka Prefecture (72) Inventor Toyoki Kunitake 1-19-3 Sakuragaoka, Shimen-cho, Kasuya-gun, Fukuoka

Claims (1)

Claims: 1. An amphipathic compound having a fluorocarbon chain and having no affinity for an organic solvent and a polar group added to both ends of the molecule, a metal alkoxide, and a radical-polymerizable monomer. Prepare a developing solution containing a non-aqueous solvent,
The developing solution is spread on the surface of a substrate to prepare a multilayer bilayer membrane of an amphipathic compound containing the radical-polymerizable monomer, and then the radical-polymerizable monomer is polymerized to two-dimensionally cross-link an ultrathin layer. A method for producing a metal oxide thin film, which comprises 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, which comprises subjecting the composite thin film containing the ultrathin layer polymer according to claim 1 to thermal treatment or chemical treatment to remove the ultrathin layer polymer.