Molecular nanopore filters

Abstract

To provide a nano pore filter that has sufficient large area and strength to be used as a filter and can capture smaller particulates such as viruses, and to provide a method for manufacturing the same.SOLUTION: There are provided: a composite structure including a molecular two-dimensional self-organizing structure including nano pores, and a nano filter; a nano pore filter including the composite structure; and a method for manufacturing the composite structure.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a nanopore filter capable of capturing fine particles, which is a composite of a two-dimensional self-assembled structure of molecules having nanopores and a nanofilter. [Background technology]

[0002] Nanofilters are characterized by their sufficient specific surface area for molecular support. In addition, nanofiber filters in particular are characterized by flexibility and high affinity with organic compounds, which are difficult to achieve with inorganic porous materials. However, because the pore size is approximately 100 nm, nanofilters can capture particles as large as fungi and PM2.5, but have difficulty capturing smaller particles such as viruses.

[0003] In recent years, research has been conducted on two-dimensional self-assembly metal-organic frameworks, and the use of their nanopores has also been considered (see, for example, Non-Patent Documents 1 to 3). However, it is difficult to make a large-area self-assembled monolayer, and since it lacks self-supporting properties, the area is insufficient (sub-mm) to be used as a filter by itself. 2 There are problems such as insufficient strength and size. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Nature Materials, 9, 565-571 (2010) [Non-patent document 2] Scientific Reports, 3, Article number: 2506 (2013) [Non-patent document 3] Chem. Soc. Rev., 47, 6267-6295 (2018) Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a filter with a large area (cm 2 The present invention aims to provide a composite structure of a nanofilter and a two-dimensional self-assembled structure of molecules with nanopores, which has nanopore size and strength and enables the capture of smaller particles such as viruses, a nanopore filter including the composite structure, and a method for producing the composite structure. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above-mentioned problems of two-dimensional self-assembled metal-organic frameworks, and have found that by combining a two-dimensional self-assembled framework made of molecules with nanopores with a nanofilter, it is possible to increase the area (cm 2 The present inventors have found that the obtained composite structure satisfies the excellent collection performance and strength required for a filter, and have completed the present invention.

[0007] The present invention is as follows: [1] A composite structure consisting of a two-dimensional self-assembled structure of molecules with nanopores and a nanofilter. [2] The composite structure according to [1], wherein the size of the nanopores is in the range of 0.5 nm to 20 nm. [3] The composite structure according to [1] or [2], wherein the molecule having the nanopore is composed of a molecule having a coordinating substituent and a metal ion. [4] The composite structure according to [3], wherein the molecule having the nanopore is a porphyrin compound. [5] The composite structure according to any one of [1] to [4], wherein the nanofilter is a nanofiber filter containing at least one organic polymer selected from the group consisting of polyacrylonitrile, polypropylene, polyurethane, nylon 6, nylon 6,6, cellulose, and cellulose derivatives. [6] The area of ​​the two-dimensional self-assembled structure of molecules with nanopores is 1 cm 2 The composite structure according to any one of [1] to [5] above. [7] The composite structure described in [3], wherein the two-dimensional self-assembled structure of molecules with nanopores is obtained by a complexation reaction at the interface between an organic solvent solution containing molecules with coordinating substituents and an aqueous solution containing metal ions. [8] The composite structure according to [7], wherein the molecule having a coordinating substituent is a porphyrin compound, and the organic solvent is at least one selected from the group consisting of aromatic hydrocarbon solvents and alcohols having 4 to 8 carbon atoms. [9] A nanopore filter comprising the composite structure according to any one of [1] to [8], the nanopore filter having a filtration accuracy of 5 nm or less.

[10] A method for producing a composite structure of a two-dimensional self-assembled structure of molecules having nanopores and a nanofiber filter, comprising: - adding a solution of an organic solvent containing molecules having a coordinating substituent group dropwise to an aqueous solution containing metal ions, thereby preparing a two-dimensional self-assembled structure of molecules having nanopores by a complexation reaction at the interface; and - A process of layering a nanofiber filter on the obtained two-dimensional self-assembled structure of molecules with nanopores to form a composite. A method comprising: [Effects of the Invention]

[0008] By supporting and compositing a two-dimensional self-assembled structure made of molecules with nanopores on a nanofilter, especially a nanofiber filter, the pore size of the resulting composite structure can be reduced from the pore size of the nanofilter (≒100 nm order) to the pore size of the two-dimensional self-assembled structure (≒several nm order). In addition, the strength of the two-dimensional self-assembled structure can be increased, and the conventional sub-mm size can be reduced. 2 Two-dimensional self-assembled structures that were previously only fabricated in sizes of a few to several hundred centimeters can now be fabricated. 2The composite structure of the present invention can be enlarged to a size of 100 mm. This allows the composite structure of the present invention to be provided as a nanoporous filter. Furthermore, the filter not only enables the capture of nanoscale substances such as viruses and fine particles, but also makes use of its porosity to reduce pressure loss. [Brief explanation of the drawings]

[0009] [Figure 1] This is a schematic diagram of a composite structure consisting of a two-dimensional self-assembled structure of molecules with nanopores and a nanofiber filter. [Figure 2] 1 is a molecular model of the H2TCPP-based Cu2+-bonded two-dimensional self-assembled structure obtained in Example 1. [Figure 3] 1 shows a transmission absorption spectrum of the H2TCPP-based Cu2+-bonded two-dimensional structure supported on the glass substrate obtained in Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0010] <composite structure> (Two-dimensional self-assembled molecular structures with nanopores) The present invention provides a composite structure comprising a two-dimensional self-assembled structure of molecules with nanopores and a nanofilter. A schematic diagram of the composite structure of the present invention is shown in Figure 1. The two-dimensional self-assembled structure of molecules with nanopores that constitutes the composite structure of the present invention is not particularly limited, as long as it is a molecule capable of forming a two-dimensional self-assembly metal-organic framework with multiple nanopores (i.e., nanoporous). Examples of such molecules include the porphyrin compounds described in Non-Patent Documents 1 to 3, the polythiol, polyamine, or polycarboxylic acid compounds described in Non-Patent Document 3, and the dipyrrin compounds described in Bull. Jpn. Soc. Coord. Chem., 67, 41-46 (2016).

[0011] In one embodiment of the present invention, the size of the nanopores in the two-dimensional self-assembled structure of molecules having nanopores is preferably less than 100 nm, more preferably 50 nm or less, even more preferably 20 nm or less, particularly preferably 10 nm or less, and also preferably 0.1 nm or more, more preferably 0.5 nm or more, and even more preferably 1 nm or more. In the present invention, the pore size may be a value calculated from a molecular model, for example, a molecular structure estimated from X-ray structural analysis.

[0012] In one embodiment of the present invention, the nanopore-forming molecule is composed of a molecule having a coordinating substituent and a metal ion. Examples of the coordinating substituent include a hydroxyl group, an imino group, an amino group, a phosphino group, a carboxyl group, or a thiol group, or a heterocycle containing any of these groups (e.g., a pyridyl group). Examples of the metal ion include an ion of a metal selected from the elements of Groups 2 to 15 of the Periodic Table. Such molecules having a coordinating substituent and compounds capable of providing a metal ion are known to those skilled in the art and can be synthesized according to known methods or obtained from reagent suppliers.

[0013] In one embodiment of the present invention, the molecule having a coordinating substituent is a porphyrin compound. Typical porphyrin compounds include compounds represented by the following formula (I). Here, porphyrin compounds also include compounds in which the π-electron conjugated system is expanded, some of the pyrrole rings are reduced, or carbon atoms at the meso positions are substituted with nitrogen.

[0014] [ka]

[0015] In the formula, M is H2 or an element selected from the elements of Groups 1 to 15 of the Periodic Table; R 1 ~R 12are each independently a hydrogen atom, an aliphatic hydrocarbon group which may have a coordinating substituent, or an aryl group or heteroaryl group which may have a coordinating substituent, Here, the coordinating substituent is a hydroxyl group, an imino group, an amino group, a phosphino group, a carboxyl group, or a thiol group, and R 1 ~R 12 At least two of the groups are phenyl groups having a coordinating substituent or heteroaryl groups having an imino group.

[0016] Here, examples of elements selected from the elements of Groups 1 to 15 of the periodic table include lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, scandium, yttrium, lanthanoid elements, actinoid elements, titanium, zirconium, hafnium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, technicium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium, mercury, boron, aluminum, gallium, indium, thallium, silicon, germanium, tin, lead, phosphorus, arsenic, antimony, and bismuth. Examples of the heteroaryl group having an imino group include a pyridyl group, a pyrimidyl group, a pyrrolyl group, and an imidazolyl group.

[0017] In a preferred embodiment of the present invention, the porphyrin compound is a compound represented by formula (I) above, wherein R 1 , R 2 , R 4 , R 5 , R 7 , R 8 , R 10 and R 11 is a hydrogen atom and R 3 , R 6 , R 9 and R 12 Two of the groups are phenyl groups and two are 4-carboxyphenyl groups, or R 3 , R 6 , R 9and R 12 is a 4-carboxyphenyl group or a 4-pyridyl group.

[0018] (nanofilter) The nanofilter constituting the composite structure of the present invention may be a nanofilter containing an inorganic or organic porous material, examples of which include alumina, silica, and zeolite, and examples of which include nanofibers and porous bodies formed from nanofibers. These materials are known to those skilled in the art and can be produced by known methods or obtained from suppliers.

[0019] In one embodiment of the present invention, the nanofilter is a porous body formed from nanofibers, i.e., a nanofiber filter. The nanofibers in the nanofiber filter of the present invention refer to fibers having an average diameter of 1000 nm or less and an aspect ratio of 100 or more. Nanofibers can be produced, for example, by electrospinning, metro-blow, and sea-island spinning. The average diameter of the nanofibers is preferably 1 to 1000 nm, more preferably 10 to 1000 nm, and even more preferably 50 to 500 nm. The average diameter of the nanofibers is calculated as the arithmetic mean value of the diameters of 100 nanofibers when observing an image of the nanofibers with a scanning electron microscope (SEM).

[0020] The nanofibers preferably contain an organic polymer. When the nanofibers contain an organic polymer, the type of organic polymer is not particularly limited and can be appropriately selected from commonly used organic polymers depending on the purpose, etc. Specific examples of organic polymers constituting the nanofibers include polyolefins such as polypropylene (PP); polyvinyls such as polyvinyl acetate (PVAc) and polyvinyl alcohol (PVA); polyesters such as polylactic acid (PLA), polylactic acid glycol (PLGA), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and polycaprolactone (PCL); polyamides (PA) such as nylon 6, nylon 6,6, and silk; polyacrylonitrile (PAN); polyurethane (PUR); polyetherimide (PEI); polyvinylidene fluoride (PVDF); polytetrafluoroethylene (PTFE); polystyrene (PS); and polysaccharides such as cellulose, cellulose derivatives, chitin, and chitosan. The organic polymer is preferably at least one selected from the group consisting of polyolefin, polyvinyl, polyester, polyamide, polyacrylonitrile, polyurethane, polyetherimide, and polysaccharide. The organic polymer contained in the nanofiber may be one type alone or a combination of two or more types.

[0021] From the viewpoint of ease of handling and durability, the organic polymer constituting the nanofiber is preferably lipophilic and oil-resistant. Here, lipophilicity refers to the wettability of the substance with oils and fats, and oil resistance means that the substance does not change in properties even when in contact with oils and fats for a long period of time, and therefore can be used without any problems. Examples of lipophilic and oil-resistant organic polymers include polyacrylonitrile, polypropylene, polyurethane, nylon 6, nylon 6,6, cellulose, and cellulose derivatives, and at least one selected from the group consisting of these is preferred.

[0022] The molecular weight of the organic polymer constituting the nanofiber is not particularly limited and can be appropriately selected depending on the purpose, etc. The molecular weight of the organic polymer is, for example, a weight average molecular weight of 10,000 to 1,000,000, and preferably 50,000 to 500,000.

[0023] From the viewpoint of ease of handling, the nanofiber filter of the present invention preferably constitutes a molded article such as a nonwoven fabric, knitted fabric, or woven fabric. That is, this embodiment encompasses a molded article containing nanofibers. The form of the molded article containing nanofibers is appropriately selected depending on the purpose, etc., and is preferably at least one selected from the group consisting of a nonwoven fabric, knitted fabric, and woven fabric, and more preferably a nonwoven fabric.

[0024] When the molded article is a nonwoven fabric, its thickness is not particularly limited and can be appropriately selected depending on the purpose, etc. By selecting the thickness of the nonwoven fabric, for example, the permeability of the nonwoven fabric to substances can be controlled. The thickness of the nonwoven fabric is, for example, 0.01 to 100 g / m2 in terms of basis weight. 2 The density can be set to 0.05 to 1 g / m 2 is preferable, and 0.1 to 0.5 g / m 2 is more preferred.

[0025] The nonwoven fabric, which is a molded product, may further contain other fibers in addition to nanofibers, as necessary. The other fibers are not particularly limited and can be appropriately selected from commonly used fibers depending on the purpose, etc. Examples of materials for the other fibers include polyolefin, polyvinyl, polyester, polyamide, polyacrylonitrile, polyurethane, polyetherimide, polysaccharides, carbon, ceramic, glass, etc. Furthermore, the other fibers may be, for example, nanofibers having an average diameter of 1 nm or more but less than 1000 nm, or fibers having an average diameter of 1 to 100 μm. The other fibers may be used alone or in combination of two or more types. When the nonwoven fabric contains other fibers, the content thereof is not particularly limited and can be appropriately selected depending on the purpose, etc.

[0026] The nonwoven fabric may be formed on a substrate. That is, the nonwoven fabric as a molded article includes a laminate including a substrate and a nonwoven fabric layer containing nanofibers arranged on the substrate. The substrate on which the nonwoven fabric layer is laminated is not particularly limited and can be appropriately selected depending on the purpose, etc. The substrate is preferably permeable to substances, and more preferably at least breathable. Examples of the substrate form include nonwoven fabric, woven fabric, knitted fabric, paper, and porous membrane. Examples of the substrate material include the organic polymers exemplified in the nanofiber section, polyolefin, polyvinyl, polyester, polyamide, polyacrylonitrile, polyurethane, polyetherimide, and polysaccharides. The substrate may be made of one material alone or a combination of two or more materials. The thickness of the substrate may be, for example, 1 μm to 5 mm. When the substrate is in the form of a nonwoven fabric, the average diameter of the fibers constituting the nonwoven fabric can be, for example, 10 to 100 μm. The basis weight of the nonwoven fabric substrate can be, for example, 10 to 100 g / m 2 It can be said that:

[0027] The laminate may further include other layers as needed in addition to the substrate and the nonwoven fabric layer. Examples of the other layers include an adhesive layer disposed between the substrate and the nonwoven fabric layer, a protective layer disposed on the nonwoven fabric layer, etc. The adhesive layer may include, for example, an adhesive material such as a thermoplastic resin.

[0028] <Method of manufacturing a composite structure> The composite structure of the present invention can be obtained by supporting the two-dimensional self-assembled structure of molecules having nanopores on the nanofilter and combining them. An example of a method for producing the composite structure of the present invention is shown below.

[0029] (Process 1) In step 1, a solution of an organic solvent containing molecules with coordinating substituents is slowly added dropwise in small amounts to an aqueous solution containing metal ions, and a complexation reaction at the interface prepares a two-dimensional self-assembled structure of molecules with nanopores.

[0030] The organic solvent solution containing molecules having a coordinating substituent may be any organic solvent that dissolves the molecules having a coordinating substituent and has low compatibility with water. Those skilled in the art can select such an organic solvent appropriately depending on the properties of the molecules having a coordinating substituent. For example, when the molecules having a coordinating substituent are porphyrin compounds, the organic solvent solution containing the porphyrin compound is preferably prepared by dissolving the porphyrin compound at an appropriate concentration, for example, 0.01 mM to 100 mM, in at least one organic solvent selected from the group consisting of aromatic hydrocarbon solvents (e.g., benzene, toluene, or xylene) and alcohols having 4 to 8 carbon atoms (e.g., n-butanol, n-pentanol, n-hexanol, or n-octanol). By using an organic solvent with low compatibility with water, the organic solvent solution containing molecules having a coordinating substituent will not dissolve in water even when dropped into an aqueous solution containing metal ions, and will spread over the water surface, resulting in a large area (several to several hundred cm). 2 It is now possible to form two-dimensional self-assembled molecular structures with nanopores (size).

[0031] The aqueous solution containing metal ions may be any solution suitable for forming a two-dimensional self-assembled structure in combination with the coordinating substituent. Such metal ions can be prepared by dissolving an inorganic compound containing the metal in water at an appropriate concentration, for example, 1 mM to 1,000 mM. Examples of such inorganic compounds include first transition metal halides, nitrates, sulfates, perchlorates, and hydrates thereof. Examples include halides such as ferric chloride (III), cobalt (II) chloride, nickel (II) chloride, and cupric chloride (II); nitrates such as ferric nitrate (III), cobalt (II) nitrate, nickel (II) nitrate, and cupric nitrate (II); sulfates such as ferric sulfate (III) and cobalt (II) sulfate; perchlorates such as ferric perchlorate (III); and hydrates thereof.

[0032] In step 1, an aqueous solution containing metal ions is placed in a shallow, flat container such as a petri dish or a tray and allowed to stand, and then a solution of an organic solvent containing molecules with coordinating substituents is slowly added dropwise using a microsyringe or other device. This causes a complexation reaction between the coordinating substituents and the metal ions at the interface between the organic solvent and water, resulting in the formation of a two-dimensional self-assembled structure.

[0033] (Process 2) In step 2, a nanofilter is layered on the resulting two-dimensional self-assembled structure of molecules with nanopores to form a composite. It is preferable to perform the composite by placing a nanofilter on top of the two-dimensional self-assembled structure while it is floating on the water surface, without isolating it, and leaving it to stand. The composite structure obtained by the composite has increased strength and can be easily removed from the water surface.

[0034] The two-dimensional self-assembled structure obtained in step 1 and the composite structure obtained in step 2 may be washed with water, if necessary, to remove excess metal ions and the like. Such a washing step may be carried out, for example, following step 1, by replacing the aqueous solution containing metal ions with water (e.g., distilled water, ion-exchanged water, pure water, or ultrapure water (Milli-Q water)). Specifically, this can be carried out by gradually replacing the aqueous solution with water using a pipette, microsyringe, tubing pump, or the like in an appropriate manner so as not to destroy the two-dimensional self-assembled structure formed in step 1 and floating on the water surface. Alternatively, following step 2, the composite structure removed from the water surface may be washed with water.

[0035] The composite structure of the present invention thus obtained can be used as a nanopore filter, and has a filtration accuracy capable of capturing not only particles of the size of fungi and PM2.5, but also smaller particles such as viruses. The filtration accuracy of the nanopore filter of the present invention is preferably 10 nm or less, more preferably 5 nm or less. Therefore, the nanopore filter of the present invention is expected to be used, for example, as an air purifying filter. [Example]

[0036] Specific embodiments of the present invention will be described below as examples, but these are merely examples and are not intended to limit the present invention.

[0037] [Example 1: Fabrication of a two-dimensional self-assembled molecular structure with nanopores] A 0.2 mM 4,4',4",4"'-(porphine-5,10,15,20-tetralyl)tetrakis(benzoic acid) (Sigma-Aldrich, hereafter referred to as H2TCPP) solution was prepared using a toluene (Kanto Chemical Co., Inc., special grade) / n-hexanol (Fujifilm Wako Pure Chemical Industries, Ltd., special grade) (3:1, v / v) mixed solvent. 50 mL of a 100 mM cupric chloride aqueous solution was placed in a 10 cm diameter Petri dish, and 150 μL of the prepared H2TCPP solution was dropped dropwise onto the cupric chloride aqueous solution using a microsyringe. A thin film (H2TCPP-based Cu) was formed on the aqueous solution by an interfacial complexation reaction. 2+ A bonded two-dimensional self-assembled structure was formed. Next, the cupric chloride solution was replaced with purified water. To prevent the high concentration of cupric chloride from adhering to the thin film, 15 mL of the solution was removed with a pipette and 15 mL of purified water was added 20 times, for a total of 300 mL of solution replacement. The thin film on top of the solution was then scooped up from below with a glass slide, and the thin film was supported on the glass slide. H2TCPP-based Cu 2+ A molecular model of the bonded 2D self-assembled structure is shown in Figure 2. The resulting thin film on the slide glass was subjected to transmission / absorption spectroscopy. The results are shown in Figure 3. The typical Soret band (422 nm) and Q band were observed in the transmission / absorption spectrum, indicating that a thin film derived from H2TCPP had been formed.

[0038] Example 2: Composite of a two-dimensional self-assembled structure of molecules with nanopores and a nanofiber filter (4 × 4 cm 2 )] (Preparation of nanofiber filters) Polypropylene spunbond nonwoven fabric 30g / m 2A polyurethane nanofiber nonwoven fabric of 0.1 g / m was fabricated using a multi-nozzle electrospinning device (manufactured by Nafias Co., Ltd.) with a thickness of 0.1 g / m. 2 The polyurethane nanofiber nonwoven fabric was fabricated by directly spinning it. The spinning solution was prepared by dissolving polyurethane resin at a concentration of 10 wt% in a mixed solvent of dimethylformamide (DMF) and methyl ethyl ketone (MEK) in a 70 / 30 ratio, and stirring the solution at room temperature for 24 hours.

[0039] (Fabrication of composite structures) A 0.2 mM H2TCPP solution was prepared using a toluene / n-hexanol (3:1, v / v) mixed solvent. 250 mL of a 100 mM cupric chloride aqueous solution was placed in a 20 cm diameter dish, and 250 μL of the prepared H2TCPP solution was dropped dropwise onto the cupric chloride aqueous solution using a microsyringe. A thin film (H2TCPP-based Cu) was formed on the aqueous solution through an interfacial complexation reaction. 2+ A bonded two-dimensional self-assembled structure was formed. Next, the cupric chloride aqueous solution was replaced with Milli-Q water. To prevent the high concentration of cupric chloride from adhering to the thin film, the solution was sucked at 60 mL / min using a tubing pump (FRONT LAB) and Milli-Q water was added by siphoning, replacing the solution by 2.5 L in total. Then, the polyurethane nanofiber filter supported on the nonwoven fabric was placed in a 4 × 4 cm 2 The nanofibers were cut out, held with tweezers, and placed with the nanofiber surface on the thin film in the solution. After leaving it for 5 minutes, the thin film was combined with the nanofiber filter.

[0040] Example 3: Composite of a two-dimensional self-assembled structure of molecules with nanopores and a nanofiber filter (15 × 15 cm 2 )] A 0.2 mM H2TCPP solution was prepared using a toluene / n-hexanol (3:1, v / v) mixed solvent. 3700 mL of 100 mM copper (II) chloride solution was placed in a PVC tray (manufactured by AS ONE Corporation), and 500 μL of the prepared H2TCPP solution was dropped dropwise onto the copper (II) chloride solution using a microsyringe. A thin film (H2TCPP-based Cu) was formed on the aqueous solution by an interfacial complexation reaction. 2+ A bonded two-dimensional self-assembled structure was formed. Next, the cupric chloride aqueous solution was replaced with Milli-Q water, and to prevent the high concentration of cupric chloride from adhering to the thin film, Milli-Q water was added at 60 mL / min using a tubing pump (FRONT LAB) while the solution was aspirated at 60 mL / min using a tubing pump (FRONT LAB), replacing the solution by a total of 5.0 L. Thereafter, a polyurethane nanofiber filter supported on a nonwoven fabric, prepared in the same manner as in Example 2, was placed on a 15 × 15 cm 2 The nanofiber was cut out, held with a latex gloved hand, and carefully placed with the nanofiber surface on the thin film on the solution. It was left to stand for 5 minutes, and the thin film was combined with the nanofiber filter. [Industrial Applicability]

[0041] The recent global pandemic of the novel coronavirus has led to an increased demand for filters capable of capturing viruses. However, when the pore size is reduced by weaving multiple fibers together, as in HEPA filters, for example, pressure loss, which reduces breathability, becomes an issue. This can be resolved to some extent by using nanofibers, but top-down methods have limitations. The composite structure of the present invention is obtained by supporting and composite a two-dimensional self-assembled structure made of molecules with nanopores on a nanofilter, and the pore size can be reduced from the pore size of the nanofilter (≒ on the order of 100 nm) to the pore size of the two-dimensional self-assembled structure (≒ on the order of several nm). In addition, composite construction increases the strength of the two-dimensional self-assembled structure and increases the cm 2As a result, the composite structure of the present invention can be provided as a nanoporous filter, and this filter is not only capable of capturing nanoscale substances such as viruses and fine particles, but also has low pressure loss due to its porosity, making it expected to be used as an air purifying filter.

Claims

1. A composite structure comprising a two-dimensional self-assembled structure of molecules having nanopores and a nanofilter containing an organic porous material, in which the two-dimensional self-assembled structure of molecules having nanopores is supported on the nanofilter as a self-assembled film having an area of ​​1 cm2 or more (however, this excludes composite structures in which nanosheets of a two-dimensional metal-organic framework having lateral dimensions on the micrometer scale are deposited on a porous support).

2. The composite structure of claim 1, wherein the nanopores have a size in the range of 0.5 nm to 20 nm.

3. 3. The composite structure according to claim 1, wherein the molecule having the nanopore is composed of a molecule having a coordinating substituent and a metal ion.

4. The composite structure according to claim 3 , wherein the nanopore-containing molecule is a porphyrin compound.

5. The nanofilter is a nanofiber filter containing at least one organic polymer selected from the group consisting of polyacrylonitrile, polypropylene, polyurethane, nylon 6, nylon 6,6, cellulose, and cellulose derivatives. The composite structure according to any one of claims 1 to 4.

6. The composite structure according to claim 3, wherein the two-dimensional self-assembled structure of molecules having nanopores is obtained by a complexation reaction at the interface between an organic solvent solution containing molecules having coordinating substituents and an aqueous solution containing metal ions.

7. 7. The composite structure according to claim 6, wherein the molecule having a coordinating substituent is a porphyrin compound, and the organic solvent is at least one selected from the group consisting of aromatic hydrocarbon solvents and alcohols having 4 to 8 carbon atoms.

8. A nanopore filter comprising the composite structure according to any one of claims 1 to 7, wherein the nanopore filter has a filtration accuracy of 5 nm or less.

9. A method for producing a composite structure of a two-dimensional self-assembled structure of molecules having nanopores and a nanofiber filter, comprising the steps of: - adding dropwise a solution of an organic solvent containing molecules having a coordinating substituent to an aqueous solution containing metal ions, and preparing a two-dimensional self-assembled structure of molecules having nanopores with an area of ​​1 cm or more by a complexation reaction at the interface; - a step of overlaying a nanofiber filter on the obtained two-dimensional self-assembled molecular structure having nanopores with an area of ​​1 cm 2 or more to form a composite; A method comprising:

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