JP2012062236A - Synthesis of mesoporous silica nanotube by using surfactant in cylindrical alumina pore as template, and the nanotube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To synthesize a mesoporous silica nanotube and to provide a silica nanotube thereof.SOLUTION: A method for producing a mesoporous silica nanotube body which has a pore parallel to a base board and having a pore diameter of at least 13 nm, which enables to be composited by inserting a protein through the pore, and a channel perpendicular to the base board and having a channel diameter of at least 100 nm, which enables a substrate to smoothly pass through the channel, includes sucking a precursor solution containing a surfactant of a triblock copolymer as a template in an alumina film by a high vacuum to thereby introduce the precursor solution in a cylindrical alumina pore formed in the alumina film, and drying the resultant to thereby produce a silica nanotube body having one-dimensional channel perpendicular to the base board and having a channel diameter of at least 100 nm and a pore parallel to the base board and having a pore diameter of at least 13 nm. The silica nanotube is manufactured by the method.

Description

  The present invention relates to a nano-sized silica nanotube body formed in a cylindrical alumina pore of an alumina membrane, and more specifically, a size that can be combined by inserting a protein molecule having a large molecular size. A one-dimensional silica nanotube body having pores, having about 13 to 14 nm pores parallel to the alumina film of the substrate, and capable of mass transfer, about 100 nm channel perpendicular to the alumina film of the substrate It is related with the silica nanotube body which has this.

  Conventionally, in silica nanotube bodies, the pore diameter is limited to about 3 to 4 nm, and it has been impossible to complex the nanotube bodies with polymers such as proteins. On the other hand, the present invention can enlarge the pore size to at least 13 nm to complex protein molecules having a large molecular size, and can move various substances. Providing new technology and new products related to silica nanotubes with a new channel structure that allows the substrate, which had previously been limited in diffusion, to move smoothly by having a channel of about 100 nm perpendicular to the substrate To do.

  One recent trend in surfactant-templated mesoporous silica is to apply the mesoporous silica to nanofluidic systems by taking advantage of the uniform pore diameter of its molecular dimensions. To that end, intense research has been conducted on the synthesis of mesoporous silica within the cylindrical alumina pores of an anodized alumina membrane.

  Here, the alumina film having mesoporous silica in the cylindrical pores of the alumina film is referred to as a mesoporous film. Growth of mesoporous silica within the cylindrical alumina pores of the alumina membrane is sometimes performed in a direction along the cylindrical alumina pores in a one-dimensional row of silica-nanotubes using a surfactant as a template. Thus, the direction of the channel in the nanotube is in a direction perpendicular to the film surface.

  Conventionally, three methods for forming mesoporous silica in the cylindrical alumina pores of an alumina membrane have been proposed. The first is growth of mesoporous silica in a precursor solution, which is a method in which an alumina film is immersed in the precursor solution and held for several hours (Non-patent Documents 1 and 2). The second is a dip coating method, in which a precursor solution is supplied into cylindrical alumina pores of an alumina film, and mesoporous silica is grown during evaporation of the solvent (Non-patent Document 3). -7).

  These methods allow for control of the ratio of silica to surfactant in the initial precursor solution, as well as temperature, or temperature, during the growth of mesoporous silica, using the surfactant as a template. There are several studies that have succeeded in synthesizing one-dimensional mesoporous membranes. However, mesoporous silica is sometimes formed not only in the cylindrical alumina pores of the alumina membrane but also on the membrane surface. Therefore, in order to obtain a mesoporous film for a nanofluidic system, the mesoporous silica on the film surface needs to be removed.

  In contrast, the present inventors have proposed another method, in which the alumina membrane is set in a normal membrane filter device, and the precursor solution is subjected to an alumina membrane under gentle stirring. Are introduced into cylindrical alumina pores. Mesoporous silica grows while the precursor solution passes through the cylindrical alumina pores of the alumina membrane, so that almost no mesoporous silica is formed on the membrane surface.

  Thus, the method proposed by the inventors appears to be suitable for synthesizing one-dimensional mesoporous membranes for use in nanofluidic systems. In fact, the present inventors synthesized a one-dimensional mesoporous film using cetyltrimethylammonium bromide (CTAB) as a template surfactant, and the size of the molecule due to the uniform channel diameter (3.4 nm). Proposed application as a nanofluidic system using the separability of non-patent material (Non-patent Document 8).

  Here, in order to contribute to the understanding of the technical features of the present invention, it will be described in more detail. Conventionally, as a prior art, conventionally, for example, a surfactant for producing a mesoporous film or an alkoxysilane compound was included. A mesoporous film having a nanotube body using a surfactant-silica nanocomposite that is spontaneously formed on a solid surface in contact with the precursor solution has been produced using the precursor solution. For this reason, the orientation of the nanochannels in the produced mesoporous film is inevitably arranged in parallel with the substrate surface.

  In this case, the movement of the substance that has entered the nanotube body having such an orientation is parallel to the substrate surface. For example, in a three-layer system of solution layer-mesoporous film-solid substrate, the mesoporous film is moved from the solution layer. It is not possible to achieve membrane permeation that permeates and moves the substance to the substrate surface. However, when the mesoporous membrane is used for separation or concentration of chemical substances, sensors for biochemical analysis, trace component analysis, polymer synthesis, catalytic reaction, etc., the nanotube body is perpendicular to the substrate surface. It is necessary to realize material permeation in the mesoporous membrane by arranging in the direction.

  Therefore, various attempts have been made to produce a porous film in which the nanotube body is substantially perpendicular to the substrate surface. Inside the nano-order macropores formed perpendicular to the substrate surface. In addition, when a pore wall is formed by introducing a precursor solution containing a surfactant, the interface between the pore wall and the solution that permeates through the macropores is perpendicular to the substrate surface. I understood. That is, if a precursor solution containing a surfactant or an alkoxysilane compound is introduced into the macropores, a nanotube body containing the surfactant micelles is formed along the pore walls. There is expected.

  The orientation of the nanotube body and the macropore is the same direction, and as a result, the nanotube body is expected to be substantially perpendicular to the substrate surface. Further, it is expected that silica nanopores from which the surfactant micelles are removed are formed by firing a mesoporous film containing nanotube bodies enclosing the surfactant micelles.

  If the film thickness of the thin film having macropores is thin and the macropores are formed so as to penetrate from the surface to the bottom surface, it is possible to produce a porous membrane containing these nanotube bodies and silica nanopores. Moreover, it is assumed that this porous membrane can be handled as a mesoporous membrane through which a substance can permeate.

  Based on the above-mentioned assumption, a nanotube body comprising an oxide layer formed by oxidizing a substrate, and including a surfactant micelle, has been formed from the surface of the oxide layer to the bottom surface. A porous membrane formed so as to penetrate is developed, and further, a porous membrane is developed in which silica nanopores are formed so as to penetrate from the surface to the bottom of the oxide layer.

  In this porous membrane, a porous membrane consisting of an oxide layer formed by oxidizing the substrate is formed so that the nanotube body containing the surfactant micelle penetrates from the surface to the bottom of the oxide layer. Has been. In this porous film, the silica nanopores are formed so as to penetrate from the surface to the bottom surface of the oxide layer in the porous film formed of the oxide layer formed by oxidizing the substrate.

  Thus, surfactant micelles are included by bringing a surfactant into contact with an oxide layer that has been formed so that macropores having a diameter of about 10 nm to several μm penetrate from the surface to the bottom. A thin film having a silica nanopore was produced by producing a thin film having a nanotube body, and further firing the oxide layer in contact with the surfactant.

  However, the mesoporous membranes synthesized so far have a limit of the pore diameter of silica nanopores of about 3 to 4 nm, and silica nanopores having pore sizes larger than that have not been synthesized. For example, in an experimental system for the permeability of a substance using a thin film having silica nanopores containing the surfactant micelles, myoglobin molecules having a molecular size of about 4.0 nm and albumin molecules having the same size of 6.4 nm are used. It has been confirmed that protein molecules having a large molecular size such as cannot pass through the membrane.

  These facts indicate that the conventional silica nanopores not only make it impossible to permeate protein molecules with large molecular sizes but also cannot be combined with them. is doing. Therefore, in this technical field, it is possible to develop a method for synthesizing a nanotube body having pores that can complex protein molecules having a large molecular size and allow the substrate to freely pass back and forth, and the nanotube body. It was strongly requested.

J. et al. Am. Chem. Soc. , 2004, 126, 8650 Chem. Mater. , 2004, 16, 4851 Langmuir, 2006, 22, 1839 Angew. Chem. Int. Ed. , 2003, 42, 4201 Nature Mater. , 2004, 3,816 Chem. Commun. , 2005, 166 Angew. Chem. Int. Ed. , 2006, 45, 1134 Nature Mater. , 2004, 3,337

  Under such circumstances, the present inventors have, for example, a one-dimensional pore size that can be complexed by inserting a protein molecule having a large molecular size in view of the above-described prior art, and further, diffusion of the substrate. As a result of intensive research aimed at developing silica nanotube bodies with two types of smooth pores, the use of a triblock copolymer surfactant as a template, the degree of vacuum during synthesis It is found that the intended purpose can be achieved by changing, improving the preparation method of the precursor solution, and improving the introduction method of the precursor solution into the alumina pores, and to complete the present invention. It came.

  The present invention expands the size of the pore diameter to at least 13 nm, for example, can be combined with a protein molecule having a large molecular size, and the substrate can be smoothly diffused to a substrate of about 100 nm. It is an object of the present invention to provide a novel nanotube body having vertical pores and a synthesis method thereof.

The present invention for solving the above-described problems comprises the following technical means.
(1) A one-dimensional silica nanotube body formed in a cylindrical alumina pore of an alumina film, the silica nanotube body having a size capable of being complexed by inserting a protein, perpendicular to the substrate And a pore having a structure parallel to the substrate, the diameter of the channel perpendicular to the substrate is at least 100 nm, and the pore diameter of the pore parallel to the substrate is at least 13 nm. Silica nanotube body.
(2) The silica nanotube body according to (1), wherein the one-dimensional silica nanotube body is formed in cylindrical alumina pores formed in a direction perpendicular to the substrate of the anodized alumina film. .
(3) The silica nanotube body according to (1) or (2), wherein the cylindrical alumina pore has a diameter of at least 200 nm and a length of at least 45 μm.
(4) A silica nanotube film obtained from the silica nanotube body according to any one of (1) to (3).
(5) A silica nanotube porous body according to any one of (1) to (3), wherein the surfactant micelle used as a template is removed.
(6) A method for producing a one-dimensional silica nanotube body having pores with a pore diameter of at least 13 nm and having a size capable of being complexed by inserting a protein, wherein triblocks are formed in the pores of the alumina membrane. By sucking a precursor solution containing a copolymer surfactant as a template, the precursor solution is introduced into the cylindrical alumina pores formed in the alumina film, and dried, whereby the cylindrical shape is obtained. Silica, characterized in that a one-dimensional silica nanotube body having at least 100 nm channels perpendicular to the substrate and at least 13 nm pores parallel to the substrate is produced in the alumina pores of A method for producing a nanotube body.
(7) The production of the silica nanotube body according to (6), wherein the one-dimensional silica nanotube body is formed in cylindrical alumina pores formed in a direction perpendicular to the substrate of the alumina film. Method.
(8) The method for producing a silica nanotube body according to (6) or (7), wherein the surfactant micelle used as a template is removed by firing the silica nanotube body under predetermined conditions.
(9) Using a triblock polymer of polyethylene oxide-polypropylene oxide-polyethylene oxide as a surfactant of a triblock copolymer system, a channel having a diameter of 100 nm perpendicular to the substrate and a diameter of 13 to 14 nm parallel to the substrate The method for producing a silica nanotube body according to any one of (6) to (8), wherein a silica nanotube body having a plurality of pores is produced.

Next, the present invention will be described in more detail.
The present invention relates to a one-dimensional silica nanotube body formed in a cylindrical alumina pore of an alumina film, for example, having a size capable of inserting and complexing protein molecules having a large molecular size, It has a vertical channel and pores (channels) parallel to the substrate, the diameter of the channel perpendicular to the substrate is about 100 nm, and the diameter of the pores parallel to the substrate is about 13 that can accommodate proteins. It is characterized by being ˜14 nm.

  In the present invention, the one-dimensional silica nanotube body is formed in cylindrical alumina pores formed in a direction perpendicular to the substrate, and the diameter of the cylindrical alumina pores is about 200 nm. The preferred embodiment is that the length is about 45 μm.

  In addition, the present invention provides a one-dimensional silica nanotube having pores parallel to a substrate having a diameter of about 13 to 14 nm and a channel having a diameter of about 100 nm perpendicular to the substrate, the size of which can be combined by inserting a protein. A precursor solution containing a triblock copolymer surfactant as a template is sucked into the pores of an alumina membrane, and the inside of the cylindrical alumina pores formed in the alumina membrane Then, the precursor solution is introduced and dried to produce a one-dimensional silica nanotube body having a pore diameter of about 13 to 14 nm in the cylindrical alumina pores. It is characterized by doing.

  In the present invention, an alumina substrate having cylindrical alumina pores is used as the substrate. This substrate is preferably composed of, for example, anodized alumina having an oxide layer produced by anodizing an Al substrate. In the oxide layer, macropores having a diameter of about 10 nm to 500 nm are formed so as to penetrate from the surface to the bottom of the oxide layer. By performing the above-described operation, a nanotube body having a uniform pore diameter of nanometer size is formed along the pore wall of the macropore.

  This nanotube body is composed of a surfactant-silica nanocomposite in which an inorganic layer such as silica and an assembly of organic molecules such as a surfactant are organized in nano order to form a so-called hydrophobic field. The nanotube body includes a surfactant micelle, and the micelle is formed so as to penetrate from the surface to the bottom of the oxide layer.

  The nanotube body may be oriented so as to be substantially perpendicular to the surface or bottom surface of the oxide layer. In addition to the nanotube body, a silica nanopore body produced by firing the nanotube body under a predetermined condition may be used. This silica nanopore body is obtained by, for example, firing the above-mentioned nanotube body at, for example, about 500 ° C. for 6 hours, and removing the surfactant micelles encapsulated as a template to form nanopores. .

  Before firing, the nanotube body configured as a surfactant-silica nanocomposite having a channel diameter of about 13 to 14 nm is re-formed as a silica nanopore body having substantially the same pore diameter after firing. In the nanotube body and the silica nanopore body having such a configuration, the nanotube body and the silica nanopore body are oriented so as to be substantially perpendicular to the interface with the surface in contact with the sample solution.

  For this reason, the sample solution in contact with the surface of the nanotube body can pass through the porous body film through the nanotube body or the silica nanopore body. These nanotube bodies and silica nanopore bodies can be applied as sensors for separation and concentration of chemical substances, biochemical analysis, trace component analysis, and in polymer synthesis and catalytic reactions. .

  In the present invention, a triblock copolymer surfactant is used as a template. In the present invention, it is important to use this triblock copolymer surfactant. As this surfactant, for example, a triblock copolymer, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock polymer, pluronic F127 (manufactured by BASF) is exemplified as a suitable one, but is not limited thereto. Any triblock copolymer having the same effect as these can be used in the same manner.

  In the present invention, a precursor solution containing this triblock copolymer surfactant is prepared. In this case, for example, PF127, which is a polyethylene oxide-polypropylene oxide-polyethylene oxide triblock polymer, is dissolved in a mixture of ethanol, aqueous HCl, and water, and then stirred in a reflux condenser for about 1 to several hours. TEOS is added thereto, and the resulting mixture is stirred with a reflux condenser for about 2 to 20 hours to prepare a precursor solution.

  In the process of preparing the precursor solution, the temperature of the mixture is maintained at about 30 to 60 ° C., for example. Next, the alumina film produced by anodic oxidation is set in a normal membrane filter device, and the above precursor solution is dropped onto the alumina film. In this case, suction is performed using a high suction device to introduce the precursor solution into the cylindrical alumina pores. After the dripped precursor solution is completely introduced into the cylindrical alumina pores, the alumina film containing the precursor solution is further sucked and dried to synthesize the mesoporous film of the present invention.

  In the method of the present invention, the cylindrical mesoporous silica is found in each cylindrical alumina pore, and on the surface of the mesoporous membrane, the remarkable mesoporous silica extending outside the alumina pore is recognized as in the conventional method. The formation of is not allowed. In the present invention, the preparation method of the precursor solution and the degree of vacuum are particularly important.

  When the stirring temperature is 60 ° C., dominant formation (95% or more) of one-dimensional silica-nanochannels is performed with stirring for about 6 to 24 hours. Thus, it has been found that the ratio of the structure of the one-dimensional silica-nanochannel to the other structure depends on the stirring time and temperature, but the channel diameter of the generated one-dimensional silica-nanotube is F127. In all cases, it is always 13 ± nm for all precursor solutions.

  When the BET surface area of each mesoporous film was analyzed from the nitrogen adsorption / desorption isotherm of the calcined mesoporous film (when the alumina film matrix was not etched), when the stirring time decreased, the BET surface area became more There is a tendency to decrease, and the highest value is obtained after stirring for about 12 hours. When a one-dimensional mesoporous film is formed using F127 as a template surfactant, the channel diameter of mesoporous silica formed in cylindrical alumina pores is 8 nm.

  On the other hand, in the case of F127, the pore diameter of the nanotube body estimated from the TEM image is 13 to 14 nm. These have a sufficient pore size size to complex protein molecules having a large molecular size such as formaldehyde dehydrogenase having a molecular size of 8.0 nm and cholinesterase having a molecular size of 12 nm. It can be suitably used as a nanotube body for complexing large protein molecules.

The present invention has the following effects.
(1) A silica nanotube body having about 100 nm diameter channels perpendicular to the substrate and about 13-14 nm diameter pores parallel to the substrate can be produced and provided.
(2) It is possible to provide a nanotube body in which protein molecules having a large molecular size can be inserted and complexed.
(3) Compared with the pore diameter (3 to 4 nm) of the conventional material, a nanotube body having a pore diameter of about 13 nm or more, which is an enlarged pore diameter, can be synthesized.
(4) With respect to mesoporous silica, it is possible to provide a nanotube body having a large pore diameter that can be complexed with a protein molecule having a large molecular size for the first time.
(5) A nanochannel body-protein complex in which a nanotube body having a pore diameter of about 13 nm or more and a protein molecule are complexed can be provided.

1 shows a membrane permeation experiment apparatus for helium permeation measurement. In helium permeation measurement, the pore diameter can be measured by increasing the water vapor pressure. The schematic diagram of the silica composite formed in the anodized alumina and the pore is shown. In the figure, A represents anodized alumina, B represents F127-M formed in the pores, and C represents P123-M formed in the pores. The result of permeation measurement of helium with an increase in water vapor pressure is shown. The vertical axis represents the helium permeation amount, and the horizontal axis represents the water vapor pressure. As shown in the figure, the transmittance decreases sharply at a certain water vapor pressure, which indicates that regular pores are open. The diagram regarding the pore diameter (nm) in FIG. 3 shows the pore diameter at that time. The electron microscope figure of the nanotube body of this invention is shown. This figure is an electron micrograph when the metal part as a support is melted by immersing the membrane in a 10% phosphoric acid solution. From the figure, it can be seen that regular lines pass from top to bottom. I can ask. a to c are SEM images, and d is a TEM image. It is a schematic diagram of the structure of a composite membrane (F127-M).

  Next, the present invention will be specifically described based on examples, but the present invention is not limited to the following examples.

  In this example, a one-dimensional mesoporous film having a wider diameter of silica-nanotube was synthesized using a triblock copolymer surfactant (BAFS, Pluronic F127) as a template. The formation of a one-dimensional mesoporous film was achieved by controlling temperature and / or humidity during the growth of mesoporous silica. However, the control of temperature and humidity is different from the conventionally proposed method. In this example, the regulation of the one-dimensional alignment of silica nanochannels using a surfactant as a template was attempted, and the conditions (temperature and stirring time) for preparing the precursor solution were examined.

  A precursor solution containing a triblock copolymer surfactant was prepared. That is, the triblock copolymer surfactant F127 (1.0 g) was dissolved in a mixture of ethanol (15 g), HCl (0.10 g of a 37 wt% aqueous solution), and water (2.0 g) to obtain The resulting mixture was stirred with a reflux condenser for 1 hour. TEOS (Tetraethoxysilane, 2.13 g) was then added to the above mixture and the resulting mixture was stirred with a reflux condenser for about 2-24 hours. After stirring, the final mixture obtained was used as a precursor solution.

  An anodized alumina membrane (membrane diameter = 4 cm, pore size = about 200 nm, thickness = about 60 μm, Whatman) was set in an ordinary membrane filter device, and the precursor solution was dropped onto the alumina membrane. The dripping of the precursor solution was performed by appropriately adjusting the respective capacities of the precursor solution of F127 within a suitable range.

  Using a suction device (Model UN820, KNF Neuberger, Inc.), rapid suction was performed to introduce the precursor solution into the cylindrical alumina pores of the alumina membrane. Then, after dripping the precursor solution completely into the alumina pores of the alumina membrane, the alumina membrane containing the precursor solution was dried by suction for about 5 minutes. Here, the tube was formed by applying a high vacuum. Hereinafter, the mesoporous film using F127 is referred to as F127-MST.

  The structure of the obtained F127-MST was evaluated by SEM. As typically shown in the F127-MST SEM, cylindrical mesoporous silica was found in each cylindrical alumina membrane, and no significant mesoporous silica form was observed on the surface of the mesoporous membrane. After the matrix of the F127-MST alumina membrane was completely etched using a 10 wt% phosphoric acid solution, cylindrical mesoporous silica was collected on the alumina membrane.

  Here, the submicron (100 nm) size material diffusion region of F127-MST needs to penetrate the film in order to move the electron carrier. Therefore, in order to confirm whether the pore penetrates the membrane, the permeation measurement of the membrane was performed using helium and water vapor. The measurement method was to flow a mixed gas of water vapor and helium, and then increase the amount of water vapor, thereby increasing the water vapor pressure and measuring the amount of permeated helium at that time. The amount of helium was measured by gas chromatography. FIG. 1 shows a membrane permeation experiment apparatus. In helium permeation measurement, the pore diameter can be measured by increasing the water vapor pressure.

As the films used, three kinds of films shown in FIG. 2 (A: anodized alumina film, B: F127-MST (may be described as F127-M) film), C: P123-M film) are used. And measured. The result is shown in FIG. When the water vapor pressure is 0.1, the A anodized alumina film is 10000 nmolm ⁻² s ⁻¹ Pa ⁻¹ , while the B F127-M film and the C P123-M film are 2000 and 500 nmolm ⁻ , respectively. It decreased to ² s ⁻¹ Pa ⁻¹ . This indicates that a composite of silica is formed in the pores of the anodized alumina film. Further, when the water vapor pressure becomes 0.63, the A anodized alumina film is almost the same, but the B F127-M film and the C P123-M film are 652 and 5.6 nmolm ⁻² s ⁻¹ , respectively. It decreased to Pa- ¹ . From the Kelvin equation, it was found to have 8-15 nm pores.

Here, as in the P123-M film in FIG. 2C, when all the pores were filled with silica, the water vapor pressure was 0.63 and almost no helium was permeated. In contrast, when the substrate has 100 nm pores as in the F127-M film in FIG. 2B, even if the water vapor pressure is 0.63, 652 nmolm ⁻² s ⁻¹ Pa ^{−. 1} helium permeation was confirmed. From the above, the pores of the F127-M film are through-holes and have numerous fine holes with a diameter of about 13 nm to 14 nm parallel to the substrate in the wall surface portion, with a diameter of about 200 nm and perpendicular to the substrate. It was found that the structure had a through hole of about 100 nm.

  The structure of the F127-M film was evaluated in more detail by SEM and TEM. The SEM and TEM measurements were performed by etching the alumina of the F127-M film with a 10% aqueous phosphoric acid solution, and then collecting cylindrical mesoporous silica. As shown in the SEM image of FIG. The aggregate of silica formed in the pores of the membrane could be observed as an aggregate of countless silica tubes having a diameter of about 200 nm by dissolving alumina. The silica tube was observed to have a one-dimensional pore having a diameter of about 100 nm.

  This indicates that higher-order nanostructures are formed on the wall surfaces of the pores of the anodized alumina film. Next, the surface of the silica tube was observed. FIG. 4b shows the result. It can be seen that this silica tube has regular pores toward the center. Further, FIG. 3c shows an SEM image with the tube halved. As a result, it was found that there were pores in the tube.

  Thereafter, TEM observation revealed that regular pores of about 13 to 14 nm were opened in equilibrium with the substrate (FIG. 4d). This structure consists of an infinite number of bundles (primary nanostructures) of microtubules with both ends open and having a diameter of about 200 nanometers (nm) and a length of about 50 μm. , A structure (secondary nanostructure) in which uniform and regular micropores with a diameter of about 13 to 14 nm are parallel to the substrate and open innumerably (sub-micron (100 nm) size) It was found to be a structure having fine pores of size.

  To summarize the above, regular streaks pass from top to bottom from the electron micrograph when the metal part as the support was dissolved by immersing the anodized alumina film in a 10% phosphoric acid solution. I can ask. The diameter and length of the mesoporous silica tube was estimated to be about 200 nm and about 45 μm, respectively. These values were independent of the type of surfactant and the preparation conditions of the precursor solution.

  As a result of examining the mesostructure of the cylindrical mesoporous silica by TEM, two mesostructures were observed for F127-M. The structure is a one-dimensional array of pores oriented in parallel along the pore walls of the cylindrical alumina membrane and a one-dimensional body of silica-nanotubes in the vertical direction. These two distinct structures can be distinguished, for example, as introducing proteins into parallel pores and passing a substrate through vertical pores.

  From the TEM image, the channel diameter of the one-dimensional silica-nanotube was estimated, and the one-dimensional pores oriented in parallel along the pore walls of the cylindrical alumina film of at least about 13 to 14 nm and at least 100 nm It was found to be a one-dimensional body of silica-nanotube with vertical pores. FIG. 5 shows a schematic diagram of the structure of F127-M, which is a composite membrane. As described above, in the membrane permeation measurement for performing the helium flow measurement on the produced silica nanotube film, the pore diameter could be measured by increasing the water vapor pressure.

  Further, in the results of the measurement of helium permeation accompanying the increase in the water vapor pressure shown in FIG. 3, the vertical axis represents the helium permeation amount and the horizontal axis represents the water vapor pressure. Diminished. This indicates that regular pores are open. The diagram regarding the pore diameter (nm) in FIG. 3 shows the pore diameter at that time. Even though the proportion of one-dimensional silica-nanotubes and other structures depends on the stirring time and temperature, the channel diameter of the one-dimensional silica-nanotubes was always 100 ± nm for all precursor solutions. Furthermore, as shown in the diagram in FIG. 3, pores of about 13 nm were confirmed by nitrogen adsorption.

  The BET surface area of each mesoporous film was analyzed from the nitrogen adsorption / desorption isotherm (when the alumina film matrix was not etched) of the calcined mesoporous film. As a result, the BET surface area tended to become smaller as the stirring time decreased, with the highest value obtained with a stirring time of about 12 hours. From the results of the above TEM and nitrogen adsorption / desorption isotherm measurements, it was concluded that the preferred conditions for obtaining a one-dimensional alignment were a stirring temperature and time of about 60 ° C. for about 12 hours.

  Even if the observed adsorption / desorption isotherm of nitrogen is used to estimate the BET surface area, the adsorption isotherm is about 13-14 nm in the pore distribution plot, regardless of the mesoporosity given by the TEM image. Did not give a significant peak. Therefore, the diameter of the one-dimensional silica-nanotube was estimated from the TEM image.

  Furthermore, the effect of the composition of TEOS and F127 in the precursor solution was investigated. As the amount of F127 in the precursor solution increased from 1.0 g (1.5 g) or decreased from 1.0 g (0.6 g), distortion of the mesostructure was observed by TEM observation. Also, mesostructure distortion was observed when the amount of TEOS was 1.28 g and 3.2 g. Accordingly, it was found that the preferred composition of TEOS and F127 for the one-dimensional mesoporous film was about 2.13 g and 1.0 g.

The estimated BET surface area was about 22 m ² g ⁻¹ and this value was independent of the conditions for the preparation of the precursor solution. In conclusion, when a one-dimensional mesoporous film is formed using F127 as a template surfactant, the cylindrical mesoporous silica formed in the pores of the cylindrical alumina film has a diameter of about It was 200 nm and the length was about 45 μm.

  Cylindrical mesoporous silica consisted of a one-dimensional array of silica-nanotubes using a surfactant as a template, and the channel diameter was about 13-14 nm. This channel diameter was about 2-4 times larger than that obtained with a CTAB type one-dimensional mesoporous film (3.4 nm). These one-dimensional mesoporous membranes can be suitably used as templates for, for example, separation of nanofluidic system molecules, chemical-sensing and bio-sensing, catalysis, and synthesis of one-dimensional nanowires.

  As described above in detail, the present invention relates to synthesis of mesoporous silica using a surfactant as a template in cylindrical alumina pores and a nanotube body thereof. According to the present invention, the conventional method synthesizes mesoporous silica. A nanotube body having a pore diameter of about 13 nm or more that could not be synthesized can be synthesized and provided. The present invention relates to a method for synthesizing a nanotube body having a large pore diameter, which can be combined by inserting protein molecules having a large molecular size, which could not be achieved by conventional materials, the nanotube body and the It is useful as one that makes it possible to provide protein complexes.

Claims (9)

  A one-dimensional silica nanotube body formed in a cylindrical alumina pore of an alumina film, the silica nanotube body having a size capable of inserting and complexing a protein, and a channel perpendicular to the substrate Silica nanotubes having a structure having pores parallel to the substrate, the diameter of the channel perpendicular to the substrate is at least 100 nm, and the pore diameter of the pores parallel to the substrate is at least 13 nm body.   The silica nanotube body according to claim 1, wherein the one-dimensional silica nanotube body is formed in cylindrical alumina pores formed in a direction perpendicular to the substrate of the anodized alumina film.   The silica nanotube body according to claim 1 or 2, wherein the cylindrical alumina pores have a diameter of at least 200 nm and a length of at least 45 µm.   A silica nanotube film obtained from the silica nanotube body according to any one of claims 1 to 3.   The silica nanotube body according to any one of claims 1 to 3, wherein the surfactant micelle used as a template is removed.   A method for producing a one-dimensional silica nanotube body having pores having a pore diameter of at least 13 nm and having a size capable of being complexed by inserting a protein, wherein a triblock copolymer is formed in the pores of an alumina film. The precursor solution containing the surfactant as a template is sucked, the precursor solution is introduced into the cylindrical alumina pores formed in the alumina film, and dried, whereby the cylindrical alumina fine particles are dried. A silica nanotube body comprising a one-dimensional silica nanotube body having at least 100 nm channels perpendicular to the substrate and at least 13 nm pores parallel to the substrate in the pores. Production method.   The method for producing a silica nanotube body according to claim 6, wherein the one-dimensional silica nanotube body is formed in cylindrical alumina pores formed in a direction perpendicular to the substrate of the alumina film.   The method for producing a silica nanotube body according to claim 6 or 7, wherein the surfactant micelle used as a template is removed by firing the silica nanotube body under predetermined conditions.   Using a triblock polymer of polyethylene oxide-polypropylene oxide-polyethylene oxide as a surfactant of a triblock copolymer system, a pore having a diameter of 13 to 14 nm parallel to the substrate having a 100 nm diameter channel perpendicular to the substrate The method for producing a silica nanotube body according to any one of claims 6 to 8, wherein a silica nanotube body having the following is produced.