JP2003335516A - Polysilicate and mesoporous body, and methods for producing them - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polysilicate having a novel structure and a method for producing the same, and a mesoporous material obtained by using the polysilicate and having a controlled shape and orientation of pore channels, and a method for producing the same. provide. SOLUTION: The polysilicate of the present invention has a structure in which silicate sheets having a six-membered ring are arranged vertically. In the method for producing a polysilicate, an aqueous solution containing a silicate is heated to remove water, and the obtained solid is heated. Further, the mesoporous material of the present invention is characterized in that the mesoporous material is made of silica and pores vertically penetrating are regularly arranged. The method for producing a mesoporous material comprises the steps of heating the above polysilicate in a basic aqueous solution in the presence of a surfactant, adjusting the solution to pH 8 to 9, and further heating; Is heated to 300 ° C. or more.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polysilicate and a mesoporous material, and a method for producing them, and more specifically, a polysilicate having a novel structure, a method for producing the same, and a method for producing the same. The present invention relates to a mesoporous material whose shape and orientation of pore channels are controlled, and a method for producing the mesoporous material. The mesoporous material of the present invention is an insulating layer for highly integrated electronic circuits, high-density magnetic recording media, optical recording media, molecular separation films,
Used for light emitting devices, chemical sensors, etc.

[0002]

2. Description of the Related Art In recent years, it has been known that a silica porous body in which pores having a diameter on the order of nanometers are regularly arranged in a honeycomb shape can be produced by the following two different methods. On the other hand, a layered polysilicate containing kanemite as an intermediate, in a basic aqueous solution, in the presence of a surfactant, to bend or bend the silicate sheet of the layered polysilicate by forming a cylindrical micelle between the layers, Further, the bent portions are bonded to each other to form a pore channel. On the other hand, by coexisting a water-soluble silicon-containing raw material and a surfactant capable of forming micelles, cylindrical silica formed along with the formation of cylindrical micelles of the surfactant is regularly arranged and deposited. Is a mesoporous silica. Each of these was a porous silica membrane in which pore channels having pores penetrating in the lateral direction were laminated.

[0003]

Mesoporous silica materials have a uniform pore size distribution on the order of nanometers.
Utilizing properties such as having a high specific surface area of around 00 m ² / g, application to various molecular adsorbing materials such as catalysts is being promoted. However, in an insulating layer (low-k material) of a highly integrated electronic circuit, a light emitting element in which pores are filled with an organic light emitting material, and further, a magnetic recording medium in which fine magnetic particles are filled in pores is used. When considering application to high-density recording media, chemical sensors, etc., it is essential for the mesoporous material to have a thin film shape in which the pores are regularly oriented in order to exhibit excellent functional characteristics.

However, in the conventional mesoporous material, cylindrical silica is regularly deposited, that is, the pore channels are oriented in the lateral direction. Therefore, such mesoporous material is used as an insulating layer for highly integrated electronic circuits. When used for (low-k material), stress is applied from the side surface of the pore channel, that is, from the top in the processing step. This type of mesoporous material having a honeycomb structure has weak mechanical strength on the side surface of the pore channels. Therefore, in the conventional mesoporous film, the pores are easily damaged in the above processing step. When a conventional mesoporous material is used for the separation membrane, the substance is permeated and separated through the inside of the pores,
Mesoporous materials in which the pore channels are oriented laterally cannot be practically used as a separation membrane. This is also the case when it is used as a chemical sensor. Furthermore, when the mesoporous material is used in a high-density recording medium, it cannot be used as a high-density recording medium unless the individual pores function as recording units, so the pore channels are oriented in the lateral direction. Therefore, it is difficult to read and write, the effective surface area involved in recording is small, and it becomes difficult to exert the effect. From the above, in order to effectively apply the mesoporous material, a material in which fine pore channels having fine pores penetrating in the vertical direction are regularly formed is required.

[0005]

The polysilicate of the present invention is characterized by having a structure in which silicate sheets having a six-membered ring are vertically arranged. Further, the method for producing a polysilicate of the present invention comprises heating a water solution containing a silicate to remove water, heating the obtained solid, and bringing the solid into contact with water to give a silicate having a six-membered ring. It is characterized in that a polysilicate having a structure in which sheets are vertically arranged is obtained.
The solid material may be thin.

The mesoporous material of the present invention comprises silica,
It is characterized in that pore channels having pores penetrating vertically are regularly formed. The mesoporous material of the present invention may have a thickness of 1 μm or less.

The method for producing a mesoporous material of the present invention is
The first step of heating the polysilicate in a basic aqueous solution in the presence of a surfactant, the second step of adjusting the pH of the solution to 8 to 9, and further heating, the obtained product to 300
It is characterized in that a third step of heating to a temperature of not less than 0 ° C. is sequentially provided. PH of the mixed solution heated in the first step
Can be 8.5 to 12.5. Further, in the third step, the obtained product may be dried and then heated. The surfactant may be a cationic surfactant.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in more detail below. The polysilicate of the present invention has a structure in which a silicate sheet having a six-membered ring is vertically arranged, as shown in FIG. 1, and more specifically, a structure in which each silicate sheet is arranged in parallel and at equal intervals. is there. Therefore, the silicate sheets are not vertically stacked unlike the generally known kanemite, macatite, kenyaite, etc. (see FIG. 2). In addition, in FIGS. 1 and 2, the appearance is assumed to be flat.

In the polysilicate of the present invention, elements constituting the raw material used for producing the polysilicate, such as sodium and potassium, may be present between the arranged silicate sheets. When such an element is present, its content ratio and existing state (bonded state) are not clear.

The method for producing a polysilicate according to the present invention can be obtained by heating an aqueous solution containing a silicate to remove water, heating the obtained solid substance, and bringing it into contact with water. The silicate is not particularly limited, and examples thereof include alkali metal salts such as sodium salt and potassium salt.
Of these, sodium silicate is preferred. Further, these may be only one kind, but may be a combination of two or more kinds, for example, a mixture of sodium salt and potassium salt.

In the present production method, the aqueous solution containing the above-mentioned silicate may be a metal component (one kind or two or more kinds) capable of forming a salt in the raw material components.
If there are two types, Na and K, etc. ) Is represented by “M ₁ ”, which is the total amount of metal components, the M ₁ / Si ratio is preferably 0.9 to 1.2, more preferably 0.95 to 1.05. If the M ₁ / Si ratio is too small or too large,
The desired polysilicate can be obtained, but the yield tends to decrease.

Further, in order to prepare an aqueous solution containing a silicate having a preferable M ₁ / Si ratio as described above,
A component containing M ₁ as a constituent element (hereinafter, also referred to as “additional component”) is contained in order to supplement the insufficient M ₁ described above. The component is not particularly limited, but is preferably a water-soluble substance. It may be an inorganic component or an organic component, but an inorganic component is preferred. Further, it may be an acidic substance or a basic substance, but a basic substance is preferable. Examples of the inorganic component include hydroxides of alkali metals such as sodium hydroxide and potassium hydroxide, carbonates such as sodium carbonate and potassium carbonate. These can be used alone or in combination of two or more. Examples of the organic component include alkoxides such as sodium ethoxide and sodium propoxide, phenoxides, carboxylic acid salts (sodium salt and potassium salt) such as sodium acetate, and sodium carboxymethyl cellulose. These can be used alone or in combination of two or more.

The method for preparing the aqueous solution containing the silicate and the additional component is not particularly limited. For example, 100 each
% (Undissolved in water), may be dissolved in water to form a (mixed) aqueous solution, or aqueous solutions dissolved in water may be used to form a (mixed) aqueous solution. Also,
One (100%) may be used as it is, and the other may be used as an aqueous solution in which water is dissolved (mixed). Examples of the aqueous solution in which the silicate is dissolved in water include water glass. Usually, an aqueous solution of silicate in water (hereinafter,
Also referred to as "silicate aqueous solution". ) And 100% of the additive component are mixed, or an aqueous solution of the silicate and an aqueous solution of the additive component are mixed to prepare an aqueous solution containing the silicate and the additive component.

The concentration of the silicate in the aqueous silicate solution is not particularly limited, but is usually 50% by weight or less, more preferably 15 to 40% by weight.

In addition to the silicate and the added components, the above aqueous solution may further contain other components as long as they do not hinder the production of the polysilicate of the present invention. Examples thereof include aluminum oxide and the like. These contents are preferably 0 to 5 parts by weight, and more preferably 0 to 2 parts by weight, when the total of Si forming the silicate and M ₁ forming the additive component is 100 parts by weight.

The water content of the aqueous solution containing the silicate and the basic component obtained as described above is then removed by heating. The heating method is not particularly limited. The heating temperature is
It is preferably 50 ° C or higher, more preferably 50 to 80 ° C. If the heating temperature is too high, bumping may occur during heating, the solid content may scatter, or the obtained solid content may become fine.

Further, it is preferable that the heating is carried out so that the solid matter after removing water has a thin shape. For example, a method of heating while foaming the aqueous solution, a method of heating a coating film formed by a pretreatment such as a spin coating method, a dip coating method, an LB film forming method, or the like can be given. When heating while foaming the aqueous solution,
The removal of water may be completed in the foamed state, but the final shape of the solid is not particularly limited, and may be thin as long as it is thin. The thickness of the solid matter obtained by heating is preferably 1 μm or less, more preferably 1 to 500 nm. As described above, by using a thin solid material, it becomes easy to obtain a polysilicate having a structure in which a silicate sheet having a six-membered ring is vertically arranged. If the thickness of the solid material is too large, the silicate sheet having a 6-membered ring may not be arranged vertically.

The solid material obtained as described above is further heated. The heating conditions such as temperature, heating rate, and atmosphere are not particularly limited. The heating temperature is preferably 600 to 80
The temperature is in the range of 0 ° C, more preferably in the range of 650 to 750 ° C. If the temperature is too low, the yield of the target crystalline substance tends to decrease. On the other hand, if it is too high, it tends to change to another crystal phase. The atmosphere during heating is usually the atmosphere. By heating the solid matter under the above preferable conditions, a substance having good crystallinity can be obtained. For example, when a raw material mainly containing sodium silicate and composed only of Si element and Na element is used, crystalline sodium silicate can be obtained. After the heating, the polysilicate of the present invention can be obtained by bringing it into contact with water. The method of contacting with water is not particularly limited, and examples thereof include a method of putting a heated solid content in water. The contact time, temperature, etc. are not particularly limited. From the above, a polysilicate having a structure in which silicate sheets having a six-membered ring are vertically arranged can be obtained.

The mesoporous material of the present invention comprises silica
The pore channels having the pores penetrating vertically are regularly formed. The pore size of the mesoporous material is preferably 10 nm or less, more preferably 2 to 4 n.
m. The thickness of the mesoporous material is almost constant,
Preferably 1 μm or less, more preferably 1 to 500 nm
Is. The shape is not particularly limited, but is usually a plate shape, a curved surface shape, or a cylindrical shape.

The mesoporous material of the present invention can be produced using the polysilicate described above. That is, the first step of heating the polysilicate in the presence of a surfactant in a basic aqueous solution, the second step of adjusting the pH of the solution to 8 to 9, and further heating, the obtained product at 500 ° C. The third step of heating above is sequentially provided.

In the first step, the method of allowing the polysilicate and the surfactant to exist in the basic aqueous solution is not particularly limited. The polysilicate may be blended with a basic aqueous solution containing a surfactant, or the basic substance may be blended with water containing the polysilicate and the surfactant to dissolve it. Furthermore, blending polysilicate into a basic aqueous solution,
It may be mixed with water in which the surfactant is dissolved or dispersed. It should be noted that it is not necessary to use a basic substance as long as the following preferable pH can be achieved with only polysilicic acid and a surfactant. When a basic substance is used to form the basic aqueous solution, the substance is not particularly limited. Examples of the basic substance include sodium hydroxide, potassium hydroxide and the like. Moreover, these can be used individually by 1 type or in combination of 2 or more types. On the other hand, an acidic aqueous solution may be added to adjust the pH of the basic aqueous solution to a predetermined value. Examples of the acidic aqueous solution include aqueous solutions of hydrochloric acid, nitric acid, sulfuric acid and the like.

When the first step is continuously manufactured using the polysilicate obtained by the method for manufacturing polysilicate described above, it is preferable to use a thin-walled polysilicate. So to keep that state
The polysilicate used in the first step is preferably in a wet state to some extent. The water content is not particularly limited.

The surfactant is not particularly limited, but a cationic surfactant is preferred from the viewpoint of ion exchange with the ions of the alkali metal forming the silicate.
Examples of the cationic surfactant include an alkyl ammonium salt (however, the alkyl carbon number is preferably 12 to 18) and an alkyl trimethyl ammonium salt (however.
The number of alkyl carbon atoms is preferably 12-18. ),
Dialkyldimethylammonium salt (however, the alkyl carbon number is preferably 12 to 18), trialkylmethylammonium salt (however, the alkyl carbon number is preferably 12 to 18), alkyldimethylethylammonium salt. (However, the alkyl carbon number is preferably 12 to 18.), alkyldimethylbenzylammonium salt (however, the alkyl carbon number is preferably 1).
2-18. ), Benzyltrimethylammonium salt and the like. Of these, alkyl trimethyl ammonium salts are preferred. Moreover, these can be used individually by 1 type or in combination of 2 or more types.
The blending amount of the above surfactant is not particularly limited, but as described below, it is preferably a concentration such that micelle formation proceeds smoothly, for example, 10 to 100 g / L.

Before the heating in the first step, the basic aqueous solution contains the polysilicate and the surfactant.
The pH of this mixed solution is preferably 8.5 to 12.5,
More preferably, it is 10-11. By setting the pH of the mixed solution in the above range, the surfactant can be infiltrated in a micelle state between the silicate sheets forming the polysilicate. Apparently, it is a composite in which a surfactant is introduced between the silicate sheets. However, if the pH is too low, pore formation tends not to be uniform, while if the pH is too high, the shape of the product may change or the product may dissolve. In addition, the mixed solution may further contain other components as long as the preferable pH can be maintained. An example thereof is a buffer solution or the like.

The heating conditions in the first step are not particularly limited, but are usually 1.5 to 1.5 at a temperature in the range of 25 to 100 ° C.
5 hours, preferably 2 to 3 hours, 1 to 5 hours at a temperature in the range of 50 to 80 ° C., preferably 2 to 3 hours. By heating under this condition, the Si-O-Si bond of the silicate sheet forming the polysilicate can be loosened and further dissociated, and the silicate sheet can be bent or curved. At this time, the micelles of the surfactant are bent or curved to fill the cylindrical gaps in a cylindrical shape.
However, if the temperature is lower than 25 ° C, the reaction tends to be difficult to proceed. Even if the temperature is sufficiently high, unreacted substances tend to remain if the heating time is too short.

The basic mixed solution heated in the first step is first adjusted to pH 8 to 9, preferably pH 8 to 8.5 by the second step. Usually, it is carried out by adding an acidic component. By setting the pH of the mixed solution in the above range, the cut portions of the silicate sheet are joined together. In addition, the pH may be set to 8 or less as needed. If the pH of the mixed solution is too high, it may be difficult to form a uniform mesoporous material.

The above acidic component is not particularly limited, and either an inorganic acid or an organic acid can be used. Examples of inorganic acids include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid and the like. Examples of the organic acid include carboxylic acids such as formic acid and acetic acid, sulfonic acid, sulfinic acid and the like. These can be used alone or in combination of two or more.

The heating conditions in the second step are not particularly limited, but are usually 1 to 5 hours at a temperature of 25 to 100 ° C., preferably 2 to 4 hours, and 1 to 6 at a temperature of 50 to 70 ° C. The time is preferably 2 to 4 hours. By heating under these conditions, the portions where the cut portions of the silicate sheet are joined can be more firmly joined to each other to form a pore channel including a cylindrical micelle and having pores with uniform pore diameters.

The heating in the first step and the second step may be continuous. That is, after the end of the first step,
The mixed solution may be cooled to room temperature, or may be heated to the same temperature or a preferable temperature after the completion of the first step, while maintaining the heating state, by adjusting the pH by adding an acidic component or the like.
Here, when the heating in the first step and the second step is continuously performed, the temperature of the solution may increase due to an exothermic reaction when the acidic component is added, and thus the temperature may be 100 ° C.
Care must be taken not to exceed.

Then, in the third step, the product obtained in the second step is heated. By this heating, an organic component such as a surfactant can be removed, and a mesoporous material can be obtained in which pore channels having vertically penetrating pores are regularly arranged. The product obtained in the second step is preferably dried and then heated.

Other conditions (heating rate, heating time, etc.) are not particularly limited as long as the above product is heated to 300 ° C. or higher. The heating is preferably carried out at a temperature in the range of 500 to 700 ° C. for 4 to 8 hours, more preferably at a temperature in the range of 550 to 600 ° C. for 4 to 8 hours. The rate of temperature increase is preferably 70 ° C./min or less, more preferably 30 to 50 ° C./min. The atmosphere is usually the atmosphere. FIG. 3 shows a schematic explanatory diagram of the above manufacturing process.

According to the method for producing a mesoporous material of the present invention,
A mesoporous material in which fine pore channels having vertically penetrating pores are regularly arranged and formed is a mixture with a conventional mesoporous material produced when kanemite is used as a raw material for obtaining a polysilicate. May be. In order to obtain the mesoporous material of the present invention, prior to the first step, the polysilicate of the present invention having a high purity was used by dispersing it in a large amount of water and fractionating the material having a slow sedimentation rate. It can be a mesoporous material. If the sedimentation speed is fast,
It is kanemite, or the arrangement of silicate sheets is disordered.

The mesoporous material of the present invention can be made of a composite material of silicon and an element other than silicon and oxygen. Examples of the element include aluminum and magnesium. Examples of the aluminum source include sodium aluminate, aluminum sulfate, pseudoboehmite and the like. In this case, the mesoporous material has a basic composition of SiO ₂ —Al ₂ O ₃ .

[0034]

EXAMPLES The present invention will be specifically described below with reference to experimental examples. Experimental Example 1 56 g of an aqueous silicate solution having water-concentration of sodium silicate as the main component (concentration 63% by weight) to which water was added to make the concentration 20% by weight equivalent to sodium silicate, and Na / in the mixed solution was added.
A 1N-sodium hydroxide aqueous solution was added so that the Si ratio was approximately 1, and they were mixed sufficiently. Next, this mixed solution was heated at 80 ° C. to remove water, and an amorphous solid sodium silicate was obtained. Then, this sodium silicate was heated from room temperature to 50
The temperature was raised to 700 ° C at a rate of ° C / min, and the temperature was maintained for 6 hours. By this heating, sodium silicate foamed vigorously and the apparent bulk expanded several tens of times. Then, the temperature was returned to room temperature, and 20 g of a flaky crystalline substance (sodium silicate) thinned by foaming (thickness of 1 μm or less) was obtained. Then, 200 g of water was added to the total amount of this crystalline substance, and the mixture was allowed to stand for 3 hours and then filtered. The residue was collected, one of the thin pieces was sampled, and was measured by an electron beam diffractometer from a direction perpendicular to the thin pieces. As a result, polysilicate having no kanemite (see FIG. 4) was obtained. It was found that the silicate sheets were arranged vertically. A transmission electron microscope (TEM) photograph of this small piece is shown in FIG.
Incidentally, the polysilicate having such a structure has about 3
It was 0% (hereinafter, this polysilicate is referred to as "polysilicate A"). Further, elemental analysis by EDS revealed that the compound was a compound containing O, Na and Si as constituent elements, as shown in FIG. (Note that C in FIG. 6 is derived from the sample stage.) For reference, an electron diffraction image of kanemite measured in the same manner is shown in FIG. The <110> orientation of kanemite is approximately 13. <1> from <010>, which is the lamination orientation of the silicate sheet of kanemite.
In the case of the film-like kanemite, which is inclined by 5 degrees, it is judged that the silicate sheets are laminated almost parallel to the thickness direction.

Next, the recovered residue (dry weight: 15 g) was poured into 350 g of water while keeping it in a wet state. To this, 17.8 g of hexadecyltrimethylammonium bromide as a surfactant was added, and the mixture was heated at 70 ° C. for 3 hours while maintaining the pH at 11. Then, the pH of the solution was adjusted to 8.5 by adding a 2N-hydrochloric acid aqueous solution, and the pH was adjusted to 70.
Heated at ° C for 3 hours. Then, it returned to room temperature and filtered. Then, the collected residue was dried at 95 ° C. for 20 hours. Then, by calcining at 550 ° C. for 6 hours to decompose and remove organic components such as a surfactant, a thickness of several tens of nm
A mesoporous silica film was obtained. When the obtained mesoporous silica was observed by TEM, the pore size was about 3
It was found that the pore channels were regularly arranged in the vertical direction (see FIG. 8).

Experimental Example 2 10 g of the flaky thin crystalline material (sodium silicate) obtained in Experimental Example 1 was added to 100 g of water, and they were sufficiently mixed and dispersed. Then, let it stand,
Spheronization was performed to compare the properties of the components with different sedimentation rates. As a result, it was found that the component having a fast sedimentation rate was polymorphic silicate or kanemite having an irregular shape, and the component having a slow sedimentation rate contained a large amount of thin-walled crystalline polysilicate (A). . Then, about 50% of the solid content of the preparative component having a slow sedimentation rate was the polysilicate (A) having the same novel structure as in Experimental Example 1, and the rest was kanemite. Next, using the solid content of the preparative component having a slow sedimentation rate, water and a surfactant (hexadecyltrimethylammonium bromide) were added in the same manner as in Experimental Example 1 to adjust the pH to 11. Then, the mixed solution was heated to 45 ° C., and part of the solution was reacted for 1 hour and the rest was reacted for 3 hours. afterwards,
In both the mixed solutions, a 2N-hydrochloric acid aqueous solution was added while keeping the liquid temperature at 45 ° C. to adjust the pH of the solution to 8.5, and the solution was maintained for 5 hours. When the product obtained was observed by TEM, it was found that the product obtained by reacting for 3 hours before adding the hydrochloric acid aqueous solution had pores whose pore diameters were substantially constant and the pore channels were regularly arranged in the vertical direction. About 50% of aligned mesoporous silica was contained. On the other hand, in the product obtained by reacting for 1 hour before adding an aqueous solution of hydrochloric acid, mesoporous silica had low regularity of pore arrangement.

Experimental Example 3 Using the flaky crystalline substance (sodium silicate) obtained in Experimental Example 1 by foaming, water and a surfactant (hexadecyl) were used in the same manner as in Experimental Example 1. Trimethylammonium bromide) was added to adjust the pH to 12.5. This was heated at 70 ° C. for 3 hours, and mesoporous silica was obtained in the same manner as in Experimental Example 1 below. When observing the obtained mesoporous silica with a TEM, most of them were in the form of irregular particles.

Effects of Examples From Experimental Example 1, it is understood that the polysilicate having a novel structure can be easily obtained by making the raw material sodium silicate thin. Further, by using the above polysilicate, by heating a basic solution containing a surfactant and adjusted to an appropriate pH,
It can be seen that the mesoporous silica in which the pore channels having the pores penetrating vertically are regularly formed is obtained.

In Experimental Example 2, considering that all of the thin-walled polysilicate obtained in Experimental Example 1 did not have a novel structure, the sedimentation rate was changed so as to separate the novel polysilicate. It was used. The component having a slow sedimentation rate contained a large amount of novel polysilicate, and the yield of the mesoporous material of the present invention could be further improved. It was also found that if the heating time in the basic solution is too short, the pores show an irregular array, and the heating time contributes significantly to the formation of the pores. On the other hand, Experimental Example 3 is an example in which the basic solution containing the polysilicate and the surfactant was adjusted to pH 12.5, and since the Si—O—Si bond of the silicate sheet was dissociated more than necessary by this heating, It is considered that the particles became amorphous.

[0040]

The polysilicate of the present invention has a novel structure in which silicate sheets are vertically arranged, not a conventional structure in which silicate sheets having a six-membered ring are laminated. Further, according to the method for producing a polysilicate of the present invention, the polysilicate having the above structure can be easily produced in a large area. In particular, when the aqueous solution containing the raw material components is heated, the thickness can be reduced to obtain a polysilicate in which the silicate sheets are more regularly arranged.

In the mesoporous material of the present invention, since the pore channels are regularly arranged, the mechanical strength in the vertical direction is high, and the thickness can be easily controlled by machining or the like. Taking advantage of this property, it can be suitably used for an insulating layer of a highly integrated electronic circuit. Further, since many pores are arranged on the surface, they are useful as a high-density recording material for magnetic recording or optical recording in which the pores are a recording unit, and reading and writing of recording are very efficient. In terms of recording density, when used as a normal 3.5-inch disk, in principle 2
It seems to exceed 00TB. Further, when the mesoporous material of the present invention is used for a separation membrane of a substance, the substance is permeated and separated through the pores, and therefore the structure has pores vertically penetrating the side surface. It can be processed in a larger area than when it has pores, and the transmittance is dramatically improved. This circumstance is the same when used for a chemical sensor.

According to the method for producing a mesoporous material of the present invention,
The mesoporous material as described above can be efficiently produced. In particular, by appropriately adjusting the pH of the basic solution and the heating conditions, a mesoporous material composed of more regularly arranged pore channels can be obtained. Further, by using a cationic surfactant as the surfactant, it is possible to form uniform micelles, and the pore size becomes substantially uniform.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a structure of a polysilicate of the present invention.

FIG. 2 is a schematic diagram showing the structure of a conventional polysilicate.

FIG. 3 is an explanatory schematic diagram showing a production process of the mesoporous material of the present invention.

FIG. 4 is an electron beam diffraction image of the thin-walled polysilicate obtained in Experimental Example 1, measured from above.

5 is a TEM photograph of the polysilicate obtained in Experimental Example 1. FIG.

FIG. 6 is an EDS chart of the polysilicate obtained in Experimental Example 1.

FIG. 7 is an electron beam diffraction image of kanemite.

FIG. 8: TE of mesoporous silica obtained in Experimental Example 1
It is an M photograph.

[Explanation of symbols]

1; polysilicate of the present invention, 11; silicate sheet,
12; curved and bonded silicate sheet, 2; conventional polysilicate, 3; mesoporous material, 31; pore channel.

Claims (9)

[Claims] 1. A polysilicate having a structure in which a silicate sheet having a six-membered ring is vertically arranged. 2. A structure in which a silicate sheet having a six-membered ring is vertically arranged by heating an aqueous solution containing a silicate to remove water, and heating the obtained solid to bring it into contact with water. A method for producing a polysilicate, which comprises obtaining the polysilicate according to claim 1. 3. The method for producing a polysilicic acid according to claim 2, wherein the solid material is thin. 4. A mesoporous material comprising silica, in which pore channels having pores penetrating vertically are regularly arranged and formed. 5. The mesoporous material according to claim 4, which has a thickness of 1 μm or less. 6. A method of heating the polysilicate according to claim 1 or the polysilicate obtained by the method according to claim 2 in a basic aqueous solution in the presence of a surfactant.
A step of adjusting the pH of the solution to 8 to 9 and heating the solution, and a third step of heating the obtained product to 300 ° C. or higher. Production method. 7. The method for producing a mesoporous material according to claim 6, wherein the pH of the mixed solution heated in the first step is 8.5 to 12.5. 8. The method for producing a mesoporous material according to claim 6, wherein in the third step, the obtained product is dried and then heated. 9. The method for producing a mesoporous material according to claim 6, wherein the surfactant is a cationic surfactant.