JP4645884B2 - Silica-based mesostructure and method for producing the same - Google Patents

Description

  The present invention relates to a silica-based mesostructure comprising a silicon oxide skeleton containing an organic group, and a method for producing the same.

  In recent years, mesoporous materials in which meso-sized pores (mesopores) having a pore diameter of about 1 to 50 nm are regularly arranged have attracted attention as materials for adsorbing and storing various substances. Research on the synthesis and functional development of mesoporous materials has been actively conducted.

  As one of such studies, in Japanese Patent Application Laid-Open No. 2000-219770 (Patent Document 1), a silica system in which an organic group is incorporated in a skeleton of a silica mesoporous material to form a basic skeleton itself in an organic-inorganic hybrid structure. A mesoporous material has been reported, and has attracted much attention because it is expected to function in accordance with the characteristics of the organic group introduced into the skeleton. Japanese Patent Laid-Open No. 2003-86676 (Patent Document 2) discloses a low dielectric constant film made of such a silica-based mesoporous material, and Japanese Patent Laid-Open No. 2003-263999 (Patent Document 3). ) Discloses a solid electrolyte membrane made of such a silica-based mesoporous material. However, since the silica-based mesoporous material having an organic-inorganic hybrid structure obtained in the past has a hard skeleton structure and lacks flexibility, it cannot maintain the state of a self-supporting film alone, and is formed on a substrate. There was a problem that it could be used only as a thin film (so-called coat film).

On the other hand, Ogawa et al. Used a mixture of tetramethoxysilane (Si (—OMe) ₄ : TMOS) and vinyltrimethoxysilane ((CH ₂ ═CH—) Si (—OMe) ₃ : VTMOS) as a silica raw material, It has been reported that a self-supporting film composed of a silica-based mesoporous material was obtained by using a so-called sol-gel method (M. Ogawa et al., Advanced Materials, 1998, 10, No. 14, p. 1077-1080 (non- Patent Document 1)). However, even the free-standing film obtained by Ogawa et al. Has a problem that the flexibility is insufficient and the strength is low, and the function imparted by the introduced organic group is limited. In terms of points, it was still not enough.
JP 2000-219770 A JP 2003-86676 A JP 2003-263999 A M. Ogawa et al., Advanced Materials, 1998, 10, No. 14, p.1077-1080

  The present invention has been made in view of the above-described problems of the prior art, and is a silica-based mesostructure having an organic-inorganic hybrid structure composed of a silicon oxide skeleton containing an organic group. A silica-based mesostructure having flexibility, capable of forming a self-supporting film having high flexibility and excellent strength, and capable of introducing various organic groups having high functionality into the skeleton; An object of the present invention is to provide a manufacturing method thereof.

  As a result of intensive studies to achieve the above object, the present inventors have found that the above object can be achieved by using an alkoxysilane having an organic group used as a silica raw material that satisfies a specific condition. The present invention has been completed.

That is, the silica-based mesostructure of the present invention is composed of a silicon oxide skeleton containing an organic group and exhibits an X-ray diffraction pattern having one or more peaks at a diffraction angle corresponding to a d value of 1 nm or more. A mesostructure,
The following general formula (1) or (2):

[In formulas (1) and (2), X ¹ may be the same or different and each represents a monovalent hydrolyzable group, and R ¹ represents a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, 1 , 2-butylene group, 1,3-butylene group, phenylene group, biphenylene group, diethylphenylene group, vinylene group, propenylene group, butenylene group, amide group, dimethylamino group and trimethylamine group R ² represents a divalent organic group having a carbon atom bonded to a silicon atom, and R ² represents a monovalent organic group having a carbon atom bonded to a silicon atom. ]
The presence ratio (T mol%) of the T site skeleton component derived from the first alkoxysilane represented by the following general formula (3) or (4):

Wherein (3) and ^(4), X 1, ^{R 1} and ^{R 2} have the same meanings as ^X 1, ^{R 1} and ^{R 2,} respectively formula (1) and (2), ^{R 2} is be the same or different It may be. ]
The existing ratio (D mol%) of the D site skeleton component derived from the second alkoxysilane represented by the following general formula (5) or (6):

Wherein (5) and ^(6), X 1, ^{R 1} and ^{R 2} have the same meanings as ^X 1, ^{R 1} and ^{R 2,} respectively formula (1) and (2), ^{R 2} is be the same or different It may be. ]
The following formula (F1) when the S site skeleton component abundance ratio (S mol%) derived from the third alkoxysilane represented by the following formula (F1) and T = 0: :
0.3 ≦ {(D + S) / (T + D + S)} ≦ 0.9 (F1)
{S / (D + S)} ≦ 0.6 (F2)
It is characterized by satisfying the condition represented by

The silica-based mesostructure of the present invention has an integrated value (T) of a signal corresponding to the T site skeleton component and an integrated value (D) of a signal corresponding to the D site skeleton component in ²⁹ Si-NMR. The integral value (S) of the signal corresponding to the S site skeleton component satisfies the condition expressed by the formula (F1) when T ≠ 0, and the formula (F2) when T = 0. It is preferable that

Further, silica mesostructure present invention, the center pore diameter in the pore diameter distribution curve may be a mesoporous silica material which mesopores 1~30nm are regularly formed.

  Furthermore, the silica-based mesostructure of the present invention preferably constitutes a self-supporting film having a thickness of 0.01 to 2 mm, whereby the tensile breaking strength is 1 MPa or more and the tensile breaking elongation is 5 % Of the self-supporting film is preferably obtained.

The method for producing a silica-based mesostructure according to the present invention comprises a silicon oxide skeleton containing an organic group by mixing alkoxysilane and a surfactant in a solvent to polymerize the alkoxysilane, and having a thickness of 1 nm or more. A method for producing a silica-based mesostructure showing an X-ray diffraction pattern having one or more peaks at a diffraction angle corresponding to a d value of
The following general formula (1) or (2):

[In formulas (1) and (2), X ¹ may be the same or different and each represents a monovalent hydrolyzable group, and R ¹ represents a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, 1 , 2-butylene group, 1,3-butylene group, phenylene group, biphenylene group, diethylphenylene group, vinylene group, propenylene group, butenylene group, amide group, dimethylamino group and trimethylamine group R ² represents a divalent organic group having a carbon atom bonded to a silicon atom, and R ² represents a monovalent organic group having a carbon atom bonded to a silicon atom. ]
The presence ratio (T mol%) of the T site skeleton component derived from the first alkoxysilane represented by the following general formula (3) or (4):

Wherein (3) and ^(4), X 1, ^{R 1} and ^{R 2} have the same meanings as ^X 1, ^{R 1} and ^{R 2,} respectively formula (1) and (2), ^{R 2} is be the same or different It may be. ]
The existing ratio (D mol%) of the D site skeleton component derived from the second alkoxysilane represented by the following general formula (5) or (6):

Wherein (5) and ^(6), X 1, ^{R 1} and ^{R 2} have the same meanings as ^X 1, ^{R 1} and ^{R 2,} respectively formula (1) and (2), ^{R 2} is be the same or different It may be. ]
The following formula (F1) when the S site skeleton component abundance ratio (S mol%) derived from the third alkoxysilane represented by the following formula (F1) and T = 0: :
0.3 ≦ {(D + S) / (T + D + S)} ≦ 0.9 (F1)
{S / (D + S)} ≦ 0.6 (F2)
The alkoxysilane is added to the solvent so as to satisfy the condition represented by:

  In the method for producing a silica-based mesostructure according to the present invention, a sol solution obtained by mixing the alkoxysilane and the surfactant in the solvent and partially polymerizing the alkoxysilane is formed into a film. Preferably, the method further includes the step of obtaining a self-supporting film composed of the silica-based mesostructure by removing the solvent and further polymerizing the alkoxysilane.

The method for producing a silica-based mesostructure according to the present invention is such that the mesopores having a central pore diameter of 1 to 30 nm in the pore-size distribution curve are regularly removed by removing the surfactant from the silica-based mesostructure. The method may further include a step of obtaining a silica-based mesoporous material.

  The reason why the silica-based mesostructure of the present invention makes it possible to form a self-supporting film having high flexibility and excellent strength is not necessarily clear, but the present inventors speculate as follows. That is, the presence ratio of the T site skeleton component, the D site skeleton component, and the S site skeleton component as the silica raw material for constituting the mesostructure skeleton satisfies the conditions of the above formulas (F1) and (F2). As a result, the formation of mesostructures is not hindered, and the number of siloxane bond (Si-O-Si) sites is reduced and the cross-linking density of the skeleton is reduced, and the resulting silica-based mesostructure is sufficiently flexible. The present inventors infer that the self-supporting film having excellent strength can be formed.

  According to the present invention, although it is a silica-based mesostructure having an organic-inorganic hybrid structure composed of a silicon oxide skeleton containing an organic group, it has sufficient flexibility, high flexibility and strength. It is possible to provide a silica-based mesostructure capable of forming a highly self-supporting film and introducing various organic groups having high functionality into the skeleton, and a method for producing the same.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.

  First, the silica-based mesostructure of the present invention will be described. That is, the silica-based mesostructure of the present invention uses at least one of the first, second and third alkoxysilanes described below in detail as a silica source, using a surfactant as a template. Polymerization is performed so that the abundance ratios of the T site, D site, and S site skeleton components derived from the above conditions are satisfied.

  The first alkoxysilane according to the present invention is a T-site skeleton component in a silica-based mesostructure obtained by polymerization, and is represented by the following general formula (1) or (2).

In the general formulas (1) and (2), X ¹ may be the same or different and each represents a monovalent hydrolyzable group. Examples of such a hydrolyzable group include a lower alkoxy group (preferably an alkoxy group having 1 to 5 carbon atoms), a hydroxyl group, a lower acyloxy group (preferably an acyloxy group having 1 to 5 carbon atoms), a halogen atom (a chlorine atom, Fluorine atom, bromine atom, iodine atom) and the like. Among them, a lower alkoxy group and / or a hydroxyl group is preferable from the viewpoint of easy control of the polymerization reaction. In the general formula (1), R ¹ represents a divalent organic group having a carbon atom bonded to a silicon atom, and includes a methylene group (—CH ₂ —), an ethylene group (—CH ₂ CH ₂ —), Trimethylene group (—CH ₂ CH ₂ CH ₂ —), tetramethylene group (—CH ₂ CH ₂ CH ₂ CH ₂ —), 1,2-butylene group (—CH (C ₂ H ₅ ) CH—), 1, 3-butylene group (—CH (CH ₃ ) CH ₂ CH ₂ —), phenylene group (—C ₆ H ₄ —), biphenylene group (—C ₆ H ₄ —C ₆ H ₄ —), diethylphenylene group (— C ₂ H ₄ —C ₆ H ₄ —C ₂ H ₄ —), vinylene group (—CH═CH—), propenylene group (—CH ₂ —CH═CH ₂ —), butenylene group (—CH ₂ —CH═) CH-CH ₂ -), amide group (-CO-NH-), dimethylamino group _{(-CH 2 -NH-CH 2 -} ), A trimethylamine group (—CH ₂ —N (CH ₃ ) —CH ₂ —) and the like. Among them, a methylene group, an ethylene group, a phenylene group, and a biphenylene are preferred because a silica-based mesostructure having high crystallinity tends to be obtained. Groups are preferred. Furthermore, in the above general formula (2), R ² represents a monovalent organic group having a carbon atom bonded to a silicon atom, an alkyl group having 1 to 10 carbon atoms (methyl group, ethyl group, etc.), 1 carbon atoms -10 alkenyl groups (vinyl group etc.), aryl groups (phenyl group, biphenyl group etc.), mercaptoalkyl groups (mercaptopropyl group etc.) and the like.

  Preferred examples of the first alkoxysilane include those shown below from the viewpoint that a relatively stable structure is easily obtained.

  The T site skeleton component derived from the first alkoxysilane is a site having three oxygen atoms (oxygen atoms constituting a siloxane bond or silanol group) bonded to a single silicon atom. These are represented by the following general formula (1 ′) or (2 ′).

  The second alkoxysilane according to the present invention is a D-site skeleton component in a silica-based mesostructure obtained by polymerization, and is represented by the following general formula (3) or (4).

In the general formula (3) and ^(4), X 1, ^{R 1} and ^{R 2} are each the formula (1) and (2) in a ^X 1, same meaning as ^{R 1} and ^{R 2, R 2} is It may be the same or different.

  As such a second alkoxysilane, those shown below are preferable from the viewpoint of easily obtaining a relatively stable structure.

  The D-site skeleton component derived from such a second alkoxysilane is a site where the number of oxygen atoms (oxygen atoms constituting a siloxane bond or silanol group) bonded to a single silicon atom is two. These are represented by the following general formula (3 ′) or (4 ′).

  The third alkoxysilane according to the present invention is an S site (M site, U site) skeleton component in the silica-based mesostructure obtained by polymerization, and is represented by the following general formula (5) or (6). It is expressed.

In the general formula (5) and ^(6), X 1, ^{R 1} and ^{R 2} are each the formula (1) and (2) in a ^X 1, same meaning as ^{R 1} and ^{R 2, R 2} is It may be the same or different.

  As such a third alkoxysilane, those shown below are preferable from the viewpoint of easily obtaining a relatively stable structure.

  In addition, the S site skeleton component derived from such third alkoxysilane is a site where the number of oxygen atoms (oxygen atoms constituting a siloxane bond or silanol group) bonded to a single silicon atom is one. These are represented by the following general formula (5 ′) or (6 ′).

In the present invention, the abundance ratio (T mol%) of the T site skeleton component derived from the first alkoxysilane and the abundance ratio (D mol%) of the D site skeleton component derived from the second alkoxysilane. And the existing ratio (S mol%) of the S site skeleton component derived from the third alkoxysilane,
(i) When T ≠ 0, the following formula (F1):
{(D + S) / (T + D + S)} ≧ 0.1 (F1)
Meets the conditions
(ii) When T = 0, the following formula (F2):
{S / (D + S)} ≦ 0.9] (F2)
It is necessary to satisfy the condition expressed by

  When the value of {(D + S) / (T + D + S)} in the formula (F1) is less than 0.1, a silica-based mesostructure having sufficient flexibility cannot be obtained. In addition, since the mesostructure having higher regularity tends to be obtained, this value is more preferably 0.7 or less. On the other hand, from the viewpoint that flexibility tends to be higher, the value of {(D + S) / (T + D + S)} is preferably 0.3 or more.

  If the value of {S / (D + S)} in the above formula (F2) exceeds 0.9, a silica-based mesostructure having a mesostructure cannot be obtained, and a more ordered mesostructure can be obtained. Since it exists in the tendency, it is more preferable that this value is 0.6 or less.

The existence ratio of the T site, D site, and S site skeleton components in the silica-based mesostructure of the present invention is specified by the type and ratio of the alkoxysilane used as the silica source, and analyzed by ²⁹ Si-NMR. It is also possible to do. That is, the silica-based mesostructure of the present invention includes an integrated value (T) of a signal corresponding to the T site skeleton component in ²⁹ Si-NMR and an integrated value (D) of a signal corresponding to the D site skeleton component. And the integral value (S) of the signal corresponding to the S-site skeleton component satisfies the condition expressed by the formula (F1) when T ≠ 0 and the formula (F2) when T = 0. It is preferable that

As described above, the silica-based mesostructure of the present invention is obtained by polymerizing (hydrolyzing and condensing) the above alkoxysilane using a surfactant as a template, and an organic group (R ¹ , R ² ). It has a network structure in which silicon atoms bonded to organic groups are highly crosslinked through oxygen atoms. The silica-based mesostructure of the present invention is a mesostructure showing an X-ray diffraction pattern having one or more peaks at a diffraction angle corresponding to a d value of 1 nm or more. When a peak appears in an X-ray diffraction (XRD) pattern, it means that a periodic structure having a d value corresponding to the peak angle is present in the silica-based mesostructure. Therefore, the presence of one or more peaks at a diffraction angle corresponding to a d value of 1 nm or more means that mesostructures regularly arranged at intervals of 1 nm or more are formed. More preferably, it has one or more peaks at a diffraction angle corresponding to a d value of 5 nm.

  The silica-based mesostructure of the present invention may be a silica-based mesoporous material in which a plurality of mesopores having a center pore diameter of 1 to 30 nm in the pore size distribution curve are formed. That is, by removing the surfactant from the silica-based mesostructure of the present invention obtained by polymerizing the above alkoxysilane using the surfactant as a template by a method described later, a meso having a central pore diameter of 1 to 30 nm is obtained. A silica-based mesoporous material having regularly formed pores is obtained.

  The central pore diameter is a curve (pore diameter distribution curve) in which a value (dV / dD) obtained by differentiating the pore volume (V) with respect to the pore diameter (D) is plotted against the pore diameter (D). ) At the maximum peak, and can be determined by the method described below. That is, the porous body is cooled to a liquid nitrogen temperature (−196 ° C.), nitrogen gas is introduced, the adsorption amount is determined by a constant volume method or a gravimetric method, and then the pressure of the introduced nitrogen gas is gradually increased, The adsorption amount of nitrogen gas with respect to each equilibrium pressure is plotted to obtain an adsorption isotherm. Using this adsorption isotherm, a pore size distribution curve can be obtained by a calculation method such as Cranston-Inklay method, Pollimore-Heal method, BJH method or the like.

Such a silica-based mesoporous material preferably contains 60% or more of the total pore volume in a range of ± 40% of the center pore diameter in the pore diameter distribution curve. A mesoporous material satisfying this condition means that the pore diameter is very uniform. The specific surface area of the mesoporous material is not particularly limited but is preferably 200 m ² / g or more. The specific surface area can be calculated as a BET specific surface area from the adsorption isotherm using the BET isotherm adsorption equation.

  Moreover, the pore which such a mesoporous body has is formed not only on the surface of the porous body but also inside. The arrangement state (pore arrangement structure or structure) of the pores in the mesoporous material is not particularly limited, but is preferably a 2d-hexagonal structure, a 3d-hexagonal structure, or a cubic structure. Such a pore arrangement structure may have a disordered pore arrangement structure.

  Here, that the mesoporous material has a hexagonal pore arrangement structure means that the arrangement of the pores is a hexagonal structure (S. Inagaki et al., J. Chem. Soc., Chem. Commun. , p. 680 (1993), S. Inagaki et al., Bull. Chem. Soc. Jpn., 69, p. 1449 (1996), Q. Huo et al., Science, 268, p. 1324 (1995) reference). The mesoporous material having a cubic pore arrangement structure means that the arrangement of the pores is a cubic structure (JCVartuli et al., Chem. Mater., 6, p. 2317 (1994)). Q. Huo et al., Nature, 368, p. 317 (1994)). Further, the mesoporous material having a disordered pore arrangement structure means that the arrangement of the pores is irregular (PTTanev et al., Science, 267, p.865 (1995), SA Bagshaw et al., Science, 269, p. 1242 (1995), R. Ryoo et al., J. Phys. Chem., 100, p. 17718 (1996)). The cubic structure is preferably Pm-3n, Ia-3d, Im-3m, or Fm-3m symmetry. The symmetry is determined based on a space group notation.

  The shape of the silica-based mesostructure of the present invention described above is not particularly limited, and may be in the form of particles. However, since the silica-based mesostructure of the present invention has sufficient flexibility, a self-supporting film is formed. Since it has the characteristic that it can form, it is preferable to comprise the self-supporting film | membrane. Thus, by using the silica-based mesostructure of the present invention (which may be the silica-based mesoporous material of the present invention) as a self-supporting film, the tensile strength at break is 1 MPa or more and the tensile elongation at break is 5 A self-supporting film excellent in strength of at least% is suitably obtained. In addition, although the average particle diameter at the time of making the silica-based mesostructure of the present invention into a particulate form and the film thickness at the time of making it into a film form are not particularly limited, Preferably there is. When the film thickness is less than 0.01 mm, the film tends to be independence. When the film thickness exceeds 2 mm, the merit in use as a film tends to be limited.

  Further, in the silica-based mesostructure of the present invention, various functions such as proton conductivity can be imparted by maintaining the self-supporting structure and the mesostructure by chemically modifying the organic group in the skeleton. Is possible. Moreover, it is also possible to add a polymer, a noble metal, a metal, a metal oxide, a metal complex, or the like as an additive to the surfactant to impart conductivity, optical characteristics, or the like.

  Next, the manufacturing method of the silica type mesostructure of this invention is demonstrated. That is, the method for producing the silica-based mesostructure according to the present invention is a method for producing the silica-based mesostructure according to the present invention by polymerizing the alkoxysilane by mixing the aforementioned alkoxysilane and surfactant in a solvent. In this case, at least one of the first, second and third alkoxysilanes is added to the solvent so as to satisfy the conditions represented by the mathematical formulas (F1) and (F2). It is the method characterized by doing.

  The method for polymerizing the alkoxysilane in the presence of a surfactant is not particularly limited, but an organic solvent or a mixed solvent of an organic solvent and water is used as a solvent, and the alkoxysilane is hydrolyzed in the presence of an acid or a base catalyst. It is preferable to carry out decomposition and condensation reactions. Examples of the organic solvent suitably used here include methanol, ethanol, isopropanol, n-propanol, acetone, tetrahydrofuran, ethylene glycol, glycerin and the like, and methanol or ethanol is preferable from the viewpoint of solubility of the silica raw material. Moreover, it is preferable that content of the organic solvent in setting it as a mixed solvent is 50 mass% or more.

  Examples of the acid catalyst used include mineral acids such as hydrochloric acid, nitric acid, and sulfuric acid, and the solution in the case of using the acid catalyst should be acidic with a pH of 6 or less (more preferably 1 to 4). preferable. Furthermore, examples of the basic catalyst used include sodium hydroxide, ammonium hydroxide, potassium hydroxide, and the like. When using the basic catalyst, the basic pH is 8 or more (more preferably 8 to 10). It is preferable that In addition, when there is too little content of alkoxysilane, it exists in the tendency for a uniform self-supporting film | membrane to become difficult to obtain, and on the other hand, when too much, stability of a sol solution will fall and it will tend to become difficult to handle.

  The surfactant used for obtaining the silica-based mesostructure is not particularly limited, and may be any of cationic, anionic and nonionic, specifically , Alkyltrimethylammonium, alkyltriethylammonium, dialkyldimethylammonium, benzylammonium chloride, bromide, iodide or hydroxide; fatty acid salt, alkylsulfonate, alkylphosphate, polyethylene oxide nonionic surfactant Agents, primary alkylamines and the like. These surfactants may be used alone or in combination of two or more.

Among the above surfactants, examples of the polyethylene oxide nonionic surfactant include a polyethylene oxide nonionic surfactant having a hydrocarbon group as a hydrophobic component and polyethylene oxide as a hydrophilic portion. . Such surfactants, for example, is represented by the general formula _{C n H 2n + 1 (OCH} 2 CH 2) m OH, n is 10 to 30, m can be used favorably those which are 30 . As such a surfactant, an ester of a fatty acid such as oleic acid, lauric acid, stearic acid, palmitic acid and sorbitan, or a compound obtained by adding polyethylene oxide to these esters can also be used.

Further, as such a surfactant, a triblock copolymer type polyalkylene oxide may be used. Examples of such surfactants include those composed of polyethylene oxide (EO) and polypropylene oxide (PO) and represented by the general formula (EO) _x (PO) _y (EO) _x . x and y represent the number of repetitions of EO and PO, respectively, x is preferably 5 to 110, y is preferably 15 to 70, x is preferably 13 to 106, and y is more preferably 29 to 70. Examples of the triblock copolymer include (EO) ₁₉ (PO) ₂₉ (EO) ₁₉ , (EO) ₁₃ (PO) ₇₀ (EO) ₁₃ , (EO) ₅ (PO) ₇₀ (EO) ₅ , (EO). ₁₃ (PO) ₃₀ (EO) ₁₃ , (EO) ₂₀ (PO) ₃₀ (EO) ₂₀ , (EO) ₂₆ (PO) ₃₉ (EO) ₂₆ , (EO) ₁₇ (PO) ₅₆ (EO) ₁₇ , ( EO) ₁₇ (PO) ₅₈ (EO) ₁₇ , (EO) ₂₀ (PO) ₇₀ (EO) ₂₀ , (EO) ₈₀ (PO) ₃₀ (EO) ₈₀ , (EO) ₁₀₆ (PO) ₇₀ (EO) ₁₀₆ , (EO) ₁₀₀ (PO) ₃₉ (EO) ₁₀₀ , (EO) ₁₉ (PO) ₃₃ (EO) ₁₉ , (EO) ₂₆ (PO) ₃₆ (EO) ₂₆ . These triblock copolymers are available from BASF, Aldrich, etc., and triblock copolymers having desired x and y values can be obtained at a small scale production level.

Also, a star diblock copolymer in which two polyethylene oxide (EO) chains-polypropylene oxide (PO) chains are bonded to two nitrogen atoms of ethylenediamine can be used. Examples of such star diblock copolymers include those represented by the general formula ((EO) _x (PO) _y ) ₂ NCH ₂ CH ₂ N ((PO) _y (EO) _x ) ₂ . Here, x and y represent the number of repetitions of EO and PO, respectively, x is preferably 5 to 110, y is preferably 15 to 70, x is 13 to 106, and y is 29 to 70. preferable.

Among such surfactants, a mesoporous material with high crystallinity can be obtained, and therefore a salt of alkyltrimethylammonium [C _p H _{2p + 1} N (CH ₃ ) ₃ ] (preferably a halide salt). Is preferably used. In that case, the alkyl group in the alkyltrimethylammonium preferably has 8 to 22 carbon atoms. Examples include octadecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, decyltrimethylammonium bromide, octyltrimethylammonium bromide, docosyltrimethylammonium chloride, and the like. It is done.

  The concentration of the surfactant in the solution is preferably 0.05 to 1 mol / L. If this concentration is less than the lower limit, the mesostructure formation tends to be incomplete. On the other hand, if the concentration exceeds the upper limit, the amount of the unreacted surfactant remaining in the solution increases, resulting in a uniform mesostructure. Tend to decrease.

  Further, various conditions (temperature, time, etc.) in the polymerization step are not particularly limited and are appropriately selected according to the alkoxysilane used, etc., but are generally 1 to 48 hours at a temperature of about 0 to 100 ° C. It is preferable to hydrolyze and condense the organosilicon compound over a period of time.

  Moreover, when manufacturing the self-supporting film | membrane which consists of a silica type mesostructure of this invention, what is called a sol-gel method demonstrated below is employ | adopted preferably. That is, a sol solution obtained by mixing the alkoxysilane and the surfactant in the solvent and partially polymerizing the alkoxysilane (partial hydrolysis and partial condensation reaction) is formed into a film, It is preferable to obtain a self-supporting film made of the silica-based mesostructure by removing and further polymerizing the alkoxysilane.

  The conditions for the partial polymerization of the alkoxysilane are not particularly limited, and may be the same as the polymerization conditions described above, but the reaction temperature is about 0 to 100 ° C. and the reaction time is 5 minutes. ˜24 hours.

  The method for forming the sol solution into a film is not particularly limited, and a method of casting into a mold or a method of applying to a substrate by various coating methods is suitably employed. In addition, as various coating methods, it can apply | coat using a bar coater, a roll coater, a gravure coater, etc. Moreover, dip coating, spin coating, spray coating, etc. are also possible. Further, a sol solution may be applied by an ink jet method.

  Furthermore, the conditions for removing the solvent from the film-like sol solution and further polymerizing the alkoxysilane are not particularly limited, but it is heated to room temperature or about 50 to 180 ° C. as necessary, and the time is about 1 to 48 hours. It is preferable to dry the mixture and advance the condensation reaction of the partial polymer to form a three-dimensional crosslinked structure.

Further, when the sol solution is formed into a film, an organic solvent may be added to the sol solution for dilution. By adding an organic solvent, the viscosity and solid content of the sol solution are reduced, so that the viscosity change during the film-forming process can be reduced, and the uniformity of the pore arrangement in the resulting silica-based mesostructure can be further improved. It tends to be improved. As such an organic solvent, methanol, ethanol, tetrahydrofuran, CHCl ₃ , CH ₂ Cl ₂ , C ₂ H ₄ Cl ₂ or the like can be used.

  Moreover, when obtaining the above-mentioned silica mesoporous body as the silica mesostructure of the present invention, the surfactant contained in the silica mesostructure thus obtained is removed. As a method for removing the surfactant in this manner, for example, (i) the surfactant is removed by immersing the silica-based mesostructure in an organic solvent (for example, ethanol) having high solubility in the surfactant. A method, (ii) a method of removing the surfactant by baking the silica-based mesostructure at 200 to 1000 ° C., and (iii) heating the silica-based mesostructure by immersing it in an acidic solution An ion exchange method in which is exchanged for hydrogen ions, and the like.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

(Examples 1-4 and Comparative Example 1)
The surfactants in the amounts shown in Table 1 were dissolved in a mixed solution in which H ₂ O, EtOH and 2N HCl were mixed at the blending ratio shown in the same table. To the resulting solution, the amount of alkoxysilane shown in Table 1 was added and stirred at room temperature for 1 hour. After stirring for 1 hour, a mixed solvent of EtOH / H ₂ O = 1 g / 1 g was added for dilution, and the mixture was stirred for 30 minutes. Then, 20 μl of N, N-dimethylformamide was added to the solution and stirred for 10 minutes, then cast into a Teflon container, stirred at room temperature for 24 hours, and further stirred at 60 ° C. for 24 hours to form a film-like silica system. A mesostructure (film thickness: about 0.5 mm) was obtained. In Examples 2 to 4 and Comparative Example 1, dilution with a mixed solvent of EtOH / H ₂ O = 1 g / 1 g and addition of N, N-dimethylformamide were not performed. In Table 1, C ₁₈ TMACl is octadecyltrimethylammonium chloride.

Each of the obtained silica-based mesostructures exhibits an X-ray diffraction pattern having one or more peaks at a diffraction angle corresponding to a d value of 1 nm or more, and includes T-site, D-site, and S-site skeleton components. The abundance ratio was as shown in Table 1. In addition, all of the silica-based mesostructures obtained in Examples 1 to 4 maintained the state of a self-supporting film, but the silica-based mesostructure obtained in Comparative Example 1 can maintain the state of a self-supporting film. could not. A photograph of a thin film of the silica-based mesostructure obtained in Example 1 and Comparative Example 1 is shown in FIGS. 1-2, and an X-ray diffraction pattern of the silica-based mesostructure obtained in Comparative Example 1 is shown in FIG. .

(Examples 5 to 16)
The amount of surfactant shown in Table 2 is dissolved in a mixed solution in which H ₂ O, EtOH and 2N HCl are mixed in the mixing ratio shown in the same table, and the amount of alkoxysilane shown in the same table is added to the resulting solution. A membranous silica mesostructure was obtained in the same manner as in Example 1 except that this was done. In Example 8, dilution with a mixed solvent of EtOH / H ₂ O = 1 g / 1 g and addition of N, N-dimethylformamide were not performed. Moreover, _C 16 PCl in Table 2 hexadecyl pyridinium _chloride, C 16 TEABr bromide hexadecyl triethylammonium, C16-3-1 is _{C 16 H 33 N (CH 3} ) 2 Br- (CH 2) _{3 -N (CH 3) 3 Br} , C16-3-2 is _{C 16 H 33 N (CH 3} ) 2 Br- (CH 2) 3 -N (C 2 H 5) 3 Br, the C18-3-18 _{C 18 H 37 N (CH 3} ) 2 Br- (CH 2) 3 -N (CH 3) a _{2 (C 18 H 37) Br} .

  Each of the obtained silica-based mesostructures exhibits an X-ray diffraction pattern having one or more peaks at a diffraction angle corresponding to a d value of 1 nm or more, and includes T-site, D-site, and S-site skeleton components. The abundance ratio was as shown in Table 2. Moreover, all the silica type mesostructures obtained in Examples 5 to 16 maintained the state of free-standing films. Photographs of the thin films of the silica-based mesostructures obtained in Examples 8, 10, and 16 are shown in FIGS. 4 to 6, and X-ray diffraction patterns of the silica-based mesostructures obtained in Examples 5 to 7 and 9 to 16 are shown. Are shown in FIGS.

(Examples 17 to 18)
The amount of surfactant shown in Table 3 is dissolved in a mixed solution of H ₂ O, EtOH and 2N HCl in the mixing ratio shown in the same table, and the amount of alkoxysilane shown in the same table is added to the resulting solution. A membranous silica mesostructure was obtained in the same manner as in Example 2 except that this was done.

  Each of the obtained silica-based mesostructures exhibits an X-ray diffraction pattern having one or more peaks at a diffraction angle corresponding to a d value of 1 nm or more, and includes T-site, D-site, and S-site skeleton components. Table 3 shows the abundance ratio. Moreover, all the silica type mesostructures obtained in Examples 17 to 18 maintained the state of free-standing films. X-ray diffraction patterns of the silica-based mesostructures obtained in Examples 17 to 18 are shown in FIGS.

(Examples 19 to 21)
Into a four-necked flask (volume: 200 ml) equipped with a gas introduction tube, an exhaust tube and a stirrer, the amount of alkoxysilane shown in Table 4 is placed, stirred in an ice bath for 10 minutes, and then H ₂ O, EtOH. And 2N HCl were introduced into the flask using a syringe so that the mixing ratio shown in the table was obtained. The reaction was allowed to proceed for 1 hour under the conditions of a rotation speed of 150 rpm, a nitrogen flow rate of 360 ml / min, and room temperature, and then the reaction was further allowed to proceed at 80 ° C. for 1.5 hours. After completion of the reaction, the sol solution obtained by allowing to cool for 10 minutes was added with a surfactant diluted in the amount shown in Table 4 with a 20 wt% acetone-ethanol mixed solvent, stirred, and then developed on a Teflon petri dish. After drying at room temperature for 24 hours or more, the mixture was stirred at 60 ° C. or more for 24 hours or more to obtain a membranous silica mesostructure.

  Each of the obtained silica-based mesostructures exhibits an X-ray diffraction pattern having one or more peaks at a diffraction angle corresponding to a d value of 1 nm or more, and includes T-site, D-site, and S-site skeleton components. Table 4 shows the abundance ratio. Moreover, all the silica type mesostructures obtained in Examples 19 to 21 maintained the state of a self-supporting film. The X-ray diffraction patterns of the silica mesostructures obtained in Examples 19 to 21 are shown in FIGS.

(Example 22)
The amount of surfactant shown in Table 5 is dissolved in a mixed solution of H ₂ O, EtOH and 2N HCl in the blending ratio shown in the same table, and the amount of alkoxysilane shown in the same table is added to the resulting solution. A membranous silica mesostructure was obtained in the same manner as in Example 2 except that this was done.

  Each of the obtained silica-based mesostructures exhibits an X-ray diffraction pattern having one or more peaks at a diffraction angle corresponding to a d value of 1 nm or more, and includes T-site, D-site, and S-site skeleton components. Table 5 shows the abundance ratio. Further, the silica-based mesostructure obtained in Example 22 maintained the state of a self-supporting film. The X-ray diffraction pattern of the silica-based mesostructure obtained in Example 22 is shown in FIG.

(Examples 23 to 24)
The amount of surfactant shown in Table 6 is dissolved in a mixed solution in which H ₂ O, EtOH and 2N HCl are mixed at the mixing ratio shown in the same table, and the amount of alkoxysilane shown in the same table is added to the resulting solution. A membranous silica mesostructure was obtained in the same manner as in Example 2 except that this was done. Incidentally, Brij-78 in Table 6 _C 18 _H 37 _- is _{(O-CH 2 -CH 2)} 20 -OH.

  Each of the obtained silica-based mesostructures shows an X-ray diffraction pattern having one or more peaks at a diffraction angle corresponding to a d value of 1 nm or more, and the T site skeleton component is present at a ratio of 0, Table 6 shows the existing ratio of the D site and S site skeleton components. Moreover, the silica type mesostructure obtained in Examples 23-24 maintained the state of a self-supporting film. The photo of the thin film of the silica type mesostructure obtained in Examples 23-24 is shown in FIGS. 24-25, and the X-ray diffraction pattern of the silica type mesostructure obtained in Examples 23-24 is shown in FIGS. Each is shown.

(Example 25)
The amount of surfactant shown in Table 7 is dissolved in a mixed solution in which H ₂ O, EtOH and 2N HCl are mixed at the mixing ratio shown in the same table, and the amount of alkoxysilane shown in the same table is added to the resulting solution. A membranous silica mesostructure was obtained in the same manner as in Example 2 except that this was done.

  The presence ratio of the T site skeleton component in the obtained silica-based mesostructure was 0, and the presence ratio of the D site and S site skeleton component was as shown in Table 7. The silica-based mesostructure obtained in Example 25 exhibited an X-ray diffraction pattern having one or more peaks at a diffraction angle corresponding to a d value of 1 nm or more, and maintained the state of a self-supporting film. The X-ray diffraction pattern of the silica-based mesostructure obtained in Example 25 is shown in FIG.

(Examples 26 to 27)
The amount of surfactant shown in Table 8 is dissolved in a mixed solution in which H ₂ O, EtOH and 2N HCl are mixed in the mixing ratio shown in the same table, and the amount of alkoxysilane shown in the same table is added to the resulting solution. A membranous silica mesostructure was obtained in the same manner as in Example 2 except that this was done.

  Each of the obtained silica-based mesostructures shows an X-ray diffraction pattern having one or more peaks at a diffraction angle corresponding to a d value of 1 nm or more, and the T site skeleton component is present at a ratio of 0, Table 8 shows the ratio of the D site and S site skeleton components. Moreover, the silica type mesostructure obtained in Examples 26-27 maintained the state of a self-supporting film. 29 to 30 show X-ray diffraction patterns of the silica-based mesostructures obtained in Examples 26 to 27, respectively.

(Comparative Example 2)
The amount of surfactant shown in Table 9 is dissolved in a mixed solution in which H ₂ O, EtOH and 2N HCl are mixed at the mixing ratio shown in the same table, and the amount of alkoxysilane shown in the same table is added to the resulting solution. A membranous silica mesostructure was obtained in the same manner as in Example 2 except that this was done.

  In the obtained silica-based mesostructure, the abundance ratio of the T site skeleton component was 0, and the abundance ratios of the D site and S site skeleton component were as shown in Table 9. In the silica-based mesostructure obtained in Comparative Example 2, one or more peaks did not appear at the diffraction angle corresponding to a d value of 1 nm or more, and no mesostructure was obtained.

<Tensile test>
The film-like silica mesostructures obtained in Examples 19 to 21 and Comparative Example 1 were subjected to a tensile test as follows. That is, a 5 × 50 mm square test piece was cut from the self-supporting films obtained in Examples 19 to 21 and Comparative Example 1, and a universal tester (INSTRON-5564, manufactured by INSTRON) was used. After fixing the lower end, the upper end of the test piece was pulled up at a pulling speed of 120 mm / min, and the tensile breaking strength and tensile breaking elongation of the self-supporting film were measured. The results obtained are as follows.

(Tensile breaking strength) (Tensile breaking elongation)
Example 19 3.0 MPa 26%
Example 20 2.7 MPa 18%
Example 21 2.3 MPa 10%
Comparative Example 1 Measurement not possible Measurement not possible.

  As is clear from the above results, it was confirmed that the film-like body composed of the silica-based mesostructure of the present invention is a self-supporting film having high flexibility and excellent strength.

<Surfactant removal test>
The film-like silica-based mesostructures obtained in Examples 4, 7, 13, and 14 to 16 were heated and dried at 150 ° C. for 1 hour or longer, and then maintained at 300 ° C. for 2 hours in the air for baking. As a result, the surfactant in the silica-based mesostructure was removed. When the specific surface area of the obtained film was measured, the results were as shown in Table 10.

As is clear from the results shown in Table 10, the film-like bodies obtained by removing the surfactant from the film-like silica-based mesostructure of the present invention all have a high specific surface area of 300 m ² / g or more. It was confirmed that the film was a membranous body composed of a silica-based mesoporous material in which mesopores were constructed by removing the surfactant.

  As described above, according to the present invention, although it is a silica-based mesostructure having an organic-inorganic hybrid structure composed of a silicon oxide skeleton containing an organic group, it has sufficient flexibility. A silica-based mesostructure (including a silica-based mesoporous material) that can form a self-supporting film having high flexibility and excellent strength and can introduce various organic groups with high functionality into the skeleton. ) Can be provided. The self-supporting membrane obtained by using such a silica-based mesostructure of the present invention is a very useful material whose application as an electrolyte membrane, a gas separation membrane, a selective permeable membrane and the like is expanded. Further, according to the production method of the present invention, it is possible to efficiently and reliably produce a silica-based mesostructure (including a silica-based mesoporous material) having such excellent characteristics and a self-supporting film composed thereof. It becomes possible.

2 is a photograph showing a state of a thin film of a silica-based mesostructure obtained in Example 1. 2 is a photograph showing a state of a thin film of a silica-based mesostructure obtained in Comparative Example 1. 4 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Comparative Example 1. 6 is a photograph showing a state of a thin film of a silica-based mesostructure obtained in Example 8. 6 is a photograph showing a state of a thin film of a silica-based mesostructure obtained in Example 10. 2 is a photograph showing a state of a thin film of a silica-based mesostructure obtained in Example 16. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 5. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 6. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 7. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 9. 4 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 10. 4 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 11. 4 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 12. 4 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 13. 14 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 14. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 15. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 16. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 17. 14 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 18. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 19. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 20. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 21. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 22. 6 is a photograph showing the state of a thin film of a silica-based mesostructure obtained in Example 23. 2 is a photograph showing a state of a thin film of a silica-based mesostructure obtained in Example 24. FIG. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 23. 4 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 24. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 25. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 26. 6 is a graph showing an X-ray diffraction pattern of a silica-based mesostructure obtained in Example 27.

Claims (6)

A silica-based mesostructure comprising a silicon oxide skeleton containing an organic group and having an X-ray diffraction pattern having one or more peaks at a diffraction angle corresponding to a d value of 1 nm or more,
The following general formula (1) or (2):
[In formulas (1) and (2), X ¹ may be the same or different and each represents a monovalent hydrolyzable group, and R ¹ represents a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, 1 , 2-butylene group, 1,3-butylene group, phenylene group, biphenylene group, diethylphenylene group, vinylene group, propenylene group, butenylene group, amide group, dimethylamino group and trimethylamine group R ² represents a divalent organic group having a carbon atom bonded to a silicon atom, and R ² represents a monovalent organic group having a carbon atom bonded to a silicon atom. ]
The presence ratio (T mol%) of the T site skeleton component derived from the first alkoxysilane represented by the following general formula (3) or (4):
Wherein (3) and ^(4), X 1, ^{R 1} and ^{R 2} have the same meanings as ^X 1, ^{R 1} and ^{R 2,} respectively formula (1) and (2), ^{R 2} is be the same or different It may be. ]
The existing ratio (D mol%) of the D site skeleton component derived from the second alkoxysilane represented by the following general formula (5) or (6):
Wherein (5) and ^(6), X 1, ^{R 1} and ^{R 2} have the same meanings as ^X 1, ^{R 1} and ^{R 2,} respectively formula (1) and (2), ^{R 2} is be the same or different It may be. ]
The following formula (F1) when the S site skeleton component abundance ratio (S mol%) derived from the third alkoxysilane represented by the following formula (F1) and T = 0: :
0.3 ≦ {(D + S) / (T + D + S)} ≦ 0.9 (F1)
{S / (D + S)} ≦ 0.6 (F2)
A silica-based mesostructure characterized by satisfying the condition represented by: ^{In 29} Si-NMR, the integrated value (T) of the signal corresponding to the T site skeleton component, the integrated value (D) of the signal corresponding to the D site skeleton component, and the signal corresponding to the S site skeleton component The integral value (S) satisfies the condition represented by the mathematical formula (F1) when T ≠ 0 and the mathematical formula (F2) when T = 0, wherein: The silica-based mesostructure described above. The silica-based mesostructure according to claim 1 or 2, which is a silica-based mesoporous material in which mesopores having a central pore diameter of 1 to 30 nm in the pore diameter distribution curve are regularly formed. . By mixing alkoxysilane and a surfactant in a solvent to polymerize the alkoxysilane, it is composed of a silicon oxide skeleton containing an organic group, and has a diffraction angle corresponding to a d value of 1 nm or more. A method for producing a silica-based mesostructure showing an X-ray diffraction pattern having a peak,
The following general formula (1) or (2):
[In formulas (1) and (2), X ¹ may be the same or different and each represents a monovalent hydrolyzable group, and R ¹ represents a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, 1 , 2-butylene group, 1,3-butylene group, phenylene group, biphenylene group, diethylphenylene group, vinylene group, propenylene group, butenylene group, amide group, dimethylamino group and trimethylamine group R ² represents a divalent organic group having a carbon atom bonded to a silicon atom, and R ² represents a monovalent organic group having a carbon atom bonded to a silicon atom. ]
The presence ratio (T mol%) of the T site skeleton component derived from the first alkoxysilane represented by the following general formula (3) or (4):
Wherein (3) and ^(4), X 1, ^{R 1} and ^{R 2} have the same meanings as ^X 1, ^{R 1} and ^{R 2,} respectively formula (1) and (2), ^{R 2} is be the same or different It may be. ]
The existing ratio (D mol%) of the D site skeleton component derived from the second alkoxysilane represented by the following general formula (5) or (6):
Wherein (5) and ^(6), X 1, ^{R 1} and ^{R 2} have the same meanings as ^X 1, ^{R 1} and ^{R 2,} respectively formula (1) and (2), ^{R 2} is be the same or different It may be. ]
The following formula (F1) when the S site skeleton component abundance ratio (S mol%) derived from the third alkoxysilane represented by the following formula (F1) and T = 0: :
0.3 ≦ {(D + S) / (T + D + S)} ≦ 0.9 (F1)
{S / (D + S)} ≦ 0.6 (F2)
The method for producing a silica-based mesostructure is characterized in that the alkoxysilane is added to the solvent so as to satisfy the condition represented by: A sol solution obtained by mixing the alkoxysilane and the surfactant in the solvent and partially polymerizing the alkoxysilane is formed into a film to remove the solvent and further polymerize the alkoxysilane. The method for producing a silica-based mesostructure according to claim 4 , further comprising a step of obtaining a self-supporting film composed of the silica-based mesostructure by the method described above. A step of obtaining a silica-based mesoporous material in which mesopores having a central pore diameter of 1 to 30 nm in the pore-size distribution curve are regularly formed by removing the surfactant from the silica-based mesostructure. The method for producing a silica-based mesostructure according to claim 4 or 5 , wherein