Polymer composite membrane, gas separator equipped with polymer composite membrane, and gas separation device equipped with polymer composite membrane

Abstract

To provide a polymer composite thin film that exhibits high permeability and selectivity for a prescribed gas and has a practical structural stability by combining two polymer thin films with different properties or further combining reinforcing materials (reinforcing layers).SOLUTION: A polymer composite thin film 1 is composed of a first polymer thin film 2 with selective permeability for a prescribed gas and a second polymer thin film 3 which is provided in a manner of being superimposed on the first polymer thin film 2 and includes at least an oxyethylene chain.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a polymer composite thin film mainly containing a polymer material, and in particular to a polymer composite thin film that has high functionality and significantly improved membrane strength, a gas separator and a gas separation device that include this polymer composite thin film, and a method for manufacturing the polymer composite thin film. [Background technology]

[0002] Recently, atmospheric CO has been considered a factor in climate change and global warming. 2 In light of this situation, the CO concentration in the air is increasing. 2 Atmospheric CO 2 There is a strong need for development of direct air capture (DAC) technology that can directly capture and safely and permanently store airborne contaminants.

[0003] In relation to DAC, the O 2 , H 2 Or CO 2 There is known a technology of air separation that separates gas components such as benzene, benzene, and benzene as needed and puts them to practical use (see, for example, "Air Separation: Materials, Methods, Principles and Applications - An Overview D Hazel and N Gob Chem. Sci. Rev. Lett. 2017, 6(22), 864-8731").

[0004] Specifically, air separation technologies include cryogenic distillation, which cools a gas mixture at room temperature to a liquid or solid state and separates each component by distillation, pressure swing adsorption (PSA), which adsorbs a specific gas onto an adsorbent under pressurized or normal pressure, removes the non-adsorbed components, and then desorbs the adsorbed gas by reducing the pressure, and CO is adsorbed onto a solid adsorbent such as activated carbon or zeolite. 2 After the adsorption of CO 2A method such as a solid adsorption method in which the carbon dioxide is desorbed is known.

[0005] All of these methods have the problem of high energy consumption and high processing costs for gas separation. Gas separation using polymer membranes has been widely studied as a means of creating DAC or air separation technologies that, in principle, have low energy consumption and are economically advantageous.

[0006] Regarding technology relating to gas separation membranes, a membrane for gas separation is known that includes a support layer and a selective polymer layer disposed on the support layer, the support layer including a gas permeable polymer and a hydrophilic additive dispersed in the gas permeable polymer, and the selective polymer layer including a selective polymer matrix and carbon nanotubes dispersed in the selective polymer matrix (Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2020-531260 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0008] According to the technology described in Patent Document 1, the CO 2 The transmittance is 617-807 GPU under reduced pressure, CO 2 / N 2 The selectivity is 161 to 187. Example 2A (CO under reduced pressure) does not contain carbon nanotubes in the selective polymer layer. 2 Transparency is 473GPU, CO 2 / N 2 The difference from the previous study (selectivity ratio = 194) is said to be due to the fact that the addition of carbon nanotubes improves the mechanical strength of the selective polymer layer, preventing it from being drawn into the pores of the support layer, which is a nanoporous substrate (see Patent Document 1 [Table 13], etc.).

[0009] However, although Patent Document 1 suggests that carbon nanotubes improve the mechanical strength of the selective polymer layer, it does not suggest that the selective polymer layer can be made thinner by adding carbon nanotubes and that gas permeability can be improved. However, Patent Document 1 emphasizes the importance of "preventing the selective polymer layer from being drawn into the pores of the support layer," and since the selective polymer layer facing the pores becomes more likely to be drawn into the pores by thinning the layer, increasing the risk of membrane rupture, there is no motivation to actively try to make the layer thinner.

[0010] The present invention has been devised to solve such problems of the conventional technology, and aims to provide a polymer composite thin film that has high permeability and selectivity to a specified gas and has practical structural stability (self-supporting ability) by combining two polymer thin films with different properties, or by further combining (composite) a reinforcing material, a gas separator comprising a polymer composite thin film, a gas separation device comprising a polymer composite thin film, and a method for manufacturing a polymer composite thin film. [Means for solving the problem]

[0011] The present invention, which has been made to solve the above-mentioned problems, provides a polymer composite thin film comprising a first polymer thin film having selective permeability to a predetermined gas, and a second polymer thin film superimposed on the first polymer thin film and containing at least an oxyethylene chain.

[0012] This makes it possible to obtain a polymer composite thin film that has a good balance between gas permeability and gas selectivity by combining two polymer thin films with different properties.

[0013] In the present invention, carbon nanotubes or cellulose nanofibers are dispersed in the second polymer thin film, which increases the mechanical strength of the second polymer thin film and makes it possible to reduce the thickness of the polymer composite thin film.

[0014] In the present invention, carbon nanotubes or cellulose nanofibers are dispersed in the first polymer thin film, which makes it possible to increase the mechanical strength of the first polymer thin film and reduce the thickness of the polymer composite thin film.

[0015] Furthermore, the present invention provides a reinforcing layer made of carbon nanotubes or cellulose nanofibers between the first polymer thin film and the second polymer thin film, which increases the mechanical strength of the polymer composite thin film including the reinforcing layer and makes it possible to reduce the thickness of the polymer composite thin film.

[0016] In addition, in the present invention, the second polymer thin film is composed of a crosslinked polymer containing an oxyethylene chain, which stabilizes the physical properties of the second polymer thin film and makes it possible to prevent breakage or the like of the polymer composite thin film containing the second polymer thin film.

[0017] In the present invention, the total thickness of the first polymer thin film and the second polymer thin film is set to 20 nm to 1000 nm, which makes it possible to obtain a polymer composite thin film 1 that is self-supporting and has high gas permeability and gas selectivity.

[0018] The present invention also provides a polymer composite membrane that selectively transmits carbon dioxide and oxygen from air, exhaust gas, and other gas mixtures, thereby enabling carbon dioxide concentration, oxygen enrichment, and nitrogen enrichment.

[0019] In addition, in the present invention, the first polymer thin film is mainly composed of polysiloxane, which makes it possible to manufacture the polymer composite thin film at lower cost using commonly available materials.

[0020] The present invention also provides a gas separator comprising a polymer composite thin film and a support for supporting the polymer composite thin film, whereby the gas separator can be constructed by superposing (transferring) the polymer composite thin film onto the support.

[0021] The present invention also provides a gas separation device including a gas separator and a gas supply unit that supplies gas to the gas separator, thereby making it possible to provide a gas separation device that produces oxygen-enriched air, carbon dioxide-enriched air, and nitrogen-enriched air.

[0022] In addition, in the present invention, the gas supply unit supplies gas so that the gas permeates through the second polymer membrane and then the first polymer membrane, thereby making it possible to obtain oxygen-enriched air, carbon dioxide-enriched air, and nitrogen-enriched air using a polymer composite membrane with excellent gas selectivity.

[0023] In addition, in the present invention, the gas supply unit supplies gas so that the gas permeates through the first polymer thin film and then the second polymer thin film, thereby making it possible to obtain oxygen-enriched air, carbon dioxide-enriched air, and nitrogen-enriched air with high efficiency using a polymer composite thin film with excellent gas permeability.

[0024] The present invention also provides a method for producing a polymer composite thin film, the method including: a first step of preparing an oxyethylene chain-containing polymer solution and preparing a polymer material-containing solution containing a polymer material having selective permeability to a predetermined gas when formed into a thin film; a second step of applying the oxyethylene chain-containing polymer solution onto a substrate on which a sacrificial layer has been formed so as to cover the sacrificial layer to form a second polymer thin film; a third step of crosslinking the second polymer thin film; a fourth step of applying and curing the polymer material-containing solution so as to cover the second polymer thin film after crosslinking to form a first polymer thin film; and a fifth step of dissolving the sacrificial layer and peeling off a polymer composite thin film composed of the first polymer thin film and the second polymer thin film from the substrate.

[0025] This makes it possible to manufacture a polymer composite thin film that has a good balance between gas permeability and gas selectivity by combining two polymer thin films with different properties. Effect of the Invention

[0026] Thus, according to the present invention, by combining two polymer thin films with different properties, or further combining (composite) a reinforcing material, it is possible to obtain a polymer composite thin film that has high permeability and selectivity to a specified gas and has practical structural stability (self-supporting ability), a gas separator comprising a polymer composite thin film, a gas separation device comprising a polymer composite thin film, and a method for manufacturing a polymer composite thin film. [Brief description of the drawings]

[0027] [Figure 1] 1(a) and 1(b) are explanatory diagrams showing the configuration of a polymer composite thin film 1 according to a first embodiment of the present invention and a gas separator 6 including the polymer composite thin film 1. [Diagram 2] FIG. 1(a) is an explanatory diagram showing the configuration of a polymer composite thin film 1 according to a second embodiment of the present invention and a gas separator 6 including the polymer composite thin film 1; FIG. 1(b) is an explanatory diagram showing the configuration of a polymer composite thin film 1 according to a third embodiment of the present invention and a gas separator 6 including the polymer composite thin film 1; and FIG. 1(c) is an explanatory diagram showing the configuration of a polymer composite thin film 1 according to a fourth embodiment of the present invention and a gas separator 6 including the polymer composite thin film 1. [Diagram 3] FIG. 1 is an explanatory diagram showing the configuration of a gas separation device 110 equipped with a gas separator 6 according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] (First embodiment) 1(a) and (b) are explanatory diagrams showing the configuration of a polymer composite thin film 1 according to the first embodiment of the present invention and a gas separator 6 including the polymer composite thin film 1. The gas separator 6 is composed of a polymer composite thin film 1 and a support 5. The polymer composite thin film 1 is composed of a first polymer thin film 2 having selective permeability to a predetermined gas and a second polymer thin film 3 containing at least an oxyethylene chain. The second polymer thin film 3 and the first polymer thin film 2 are both non-porous bodies, and are superimposed so as to be in contact with each other. The gas separator 6 may be configured so that the first polymer thin film 2 is in contact with the support 5 as shown in FIG. 1(a), or may be configured so that the second polymer thin film 3 is in contact with the support 5 as shown in FIG. 1(b).

[0029] The material constituting the first polymer thin film 2 may be, for example, a vinyl polymer, polysiloxane, or a cross-linked polymer, and polydimethylsiloxane (hereinafter, referred to as "PDMS") is particularly suitable. Here, it is said that vinyl polymers and polysiloxanes have low mechanical strength and cannot ensure self-supporting properties when used alone at a film thickness of, for example, 10 nm or less. In this case, it is possible to achieve both functionality and self-supporting properties by adding a reinforcing material 10 to the first polymer thin film 2 mainly composed of, for example, a vinyl polymer or polysiloxane, or by overlapping a reinforcing layer 4 on the first polymer thin film 2, as described below.

[0030] On the other hand, crosslinkable polymers are considered to be able to stand on their own even at a film thickness (for example, 100 nm or less) at which they can effectively exert their functionality. Here, a crosslinkable polymer (crosslinked polymer) refers to a polymer that has a three-dimensional network structure (crosslinked structure) formed by bonding multiple linear polymer chains through a chemical reaction, and includes, for example, radical crosslinking of linear polymers and epoxy resins in which epoxy groups and amino groups as functional groups are crosslinked through a chemical reaction.

[0031] Regarding epoxy resin, an example of a self-supporting polymer thin film with a thickness of 20 nm is A Large, Freestanding, 20nm Thick Nanomembrane Based on an Epoxy Resin, H. Watanabe T.Kunitake, ADVANCED MATERIALS Volume 19, Issue 7, Pages 909-912, 2007. (https: / / onlinelibrary.wiley.com / doi / abs / 10.1002 / adma.200601630) It is published in.

[0032] A compound containing an oxyethylene chain can be suitably used as a material constituting the second polymer thin film 3. The oxyethylene chain has gas separation properties whether it is contained in the main chain or in the side chain of the polymer. Polymer materials containing the oxyethylene chain in the main chain include polyethylene glycol diacrylate (hereinafter sometimes referred to as "PEGDA"), polyethylene glycol dimethacrylate, polyethylene glycol, and poly(ethylene oxide).

[0033] Examples of polymeric materials that may be included in the side chain include poly(ethylene glycol) methyl ether acrylate (hereinafter, sometimes referred to as "PEGMA") and poly(ethylene glycol) methyl ether methacrylate. In particular, the acrylates given as examples are preferable because they can be easily made into a high molecular weight and various acrylates can be arbitrarily combined. When making these polymeric materials into high molecular weight, the materials may be mixed and then made into high molecular weight, or each material may be made into high molecular weight and then mixed. Here, when mixing PEGMA and PDGDA, the volume ratio is preferably in the range of PEGMA:PEGDA=10:0 to 5:5. The compound containing an oxyethylene chain may be any of the so-called main chain type, side chain type, and star type, and also includes ethylene oxide polymers that are easily crosslinked by radical reaction.

[0034] The polymer raw material acrylate can be easily made into a high molecular weight by using a polymerization initiator. There is no particular restriction on the method of making it into a high molecular weight, but for example, the reaction can be advanced by heating using benzoyl peroxide. In addition, the reaction can be advanced by irradiating light using 1-hydroxycyclohexyl phenyl ketone.

[0035] Polyallylamine, polyethyleneimine, etc. may also be added as a material constituting the second polymer thin film 3. In this case, the amount of polyallylamine, etc. added may be about 10 wt % relative to PEGMA.

[0036] The first polymer thin film 2, which is mainly composed of vinyl polymers and polysiloxane, has excellent gas permeability, and the thinner the film, the higher the gas permeability becomes. The first polymer thin film 2 also has a high permeability to a specific gas (CO 2 ,O 2 ) but CO 2 / N 2 On the other hand, the second polymer thin film 3 containing oxyethylene chains has excellent gas separation performance, especially for CO 2 / N 2 However, to maintain sufficient gas permeability, it is necessary to make the film as thin as possible and / or to lower the degree of cross-linking. Therefore, by combining (composite) a first polymer thin film 2 and a second polymer thin film 3, which have different properties, a polymer composite thin film 1 having both gas permeability and gas selectivity can be obtained.

[0037] The total thickness of the first polymer thin film 2 and the second polymer thin film 3 is about 1000 GPU. 2 From the viewpoint of ensuring transmittance, it is preferably 10 nm to 2 μm, and more preferably 20 nm to 1000 nm (the same applies to the second to fourth embodiments). In the first embodiment, it is more preferable that the thickness of the first polymer thin film 2 is 30 nm or more (e.g., 120 to 1300 nm) and the thickness of the second polymer thin film 3 is 10 nm or more (e.g., 18 to 113 nm) from the viewpoint of providing self-supporting properties for the polymer composite thin film 1 as a whole.

[0038] The support 5 may be, for example, a polyacrylonitrile (hereinafter, sometimes referred to as "PAN") layer having numerous fine voids and high gas permeability, or a porous PAN membrane composed of a composite membrane having the layer on the outermost surface. Alternatively, an alumina sheet (product example: Anodisk) made porous by anodization may be used as the support 5. In addition, so-called membrane filters such as polyethersulfone, polycarbonate, and polyimide may be used.

[0039] When a predetermined gas (here, air) is supplied to the gas separator 6 including the first polymer thin film 2 and the second polymer thin film 3, carbon dioxide (CO 2 ) and oxygen (O 2 ) is selectively and more permeable (the same applies to the second to fourth embodiments). 2 Effectively recover or O 2 The concentration of can be increased.

[0040] Hereinafter, a manufacturing process of the polymer composite thin film 1 and the gas separator 6 including the polymer composite thin film 1 in the first embodiment will be described.

[0041] <Preparation> As a preliminary step to obtain an oxyethylene chain-containing polymer solution, the monomer PEGMA is first polymerized. The oxyethylene chain-containing polymer is prepared by radical polymerization of PEGMA. Toluene is used as the reaction solvent, and after the polymerization reaction, a reprecipitation operation using hexane and drying of the precipitate yields a powder of polymerized PEGMA (hereinafter sometimes referred to as "P(PEGMA)").

[0042] <1st process> The first step is a step of preparing an oxyethylene chain-containing polymer solution containing an oxyethylene chain, and preparing a polymer material-containing solution containing a polymer material that has selective permeability to a predetermined gas when thinned. Note that "preparation" in the first step includes preparation or procurement of a commercial product. Here, an oxyethylene chain-containing polymer solution in which a powder of P(PEGMA) and a photopolymerization initiator are dissolved in a predetermined solvent, and a PDMS preparation solution (polymer material-containing solution) in which PDMS, a PDMS curing agent, and a solvent are mixed in a predetermined ratio are prepared. Note that the photopolymerization initiator may be contained in a range of 0.01 to 20 wt% with respect to P(PEGMA). In addition, as a solvent for preparing the oxyethylene chain-containing polymer solution, for example, ethanol, toluene, xylene, or a mixed solvent of ethanol and water can be used. In addition, as a solvent for preparing the polymer material-containing solution, for example, hexane, toluene, and cyclohexane can be used.

[0043] <Second process> The second step is a step of applying an oxyethylene chain-containing polymer solution onto the substrate on which the sacrificial layer has been formed so as to cover the sacrificial layer, thereby forming a second polymer thin film 3. First, a water-soluble polymer is applied by spin coating onto a cleaned glass substrate (hereinafter sometimes referred to as the "substrate") to form a sacrificial layer. Next, the oxyethylene chain-containing polymer solution prepared in the first step is applied by spin coating so as to cover the sacrificial layer, thereby forming the second polymer thin film 3.

[0044] <3rd process> The third step is a step of crosslinking the second polymer thin film 3. As described above, the oxyethylene chain-containing polymer solution contains a photopolymerization initiator, and crosslinking is initiated and progressed by UV (ultraviolet) irradiation. That is, the second polymer thin film 3 is composed of a crosslinked polymer containing oxyethylene chains (a polymer layer in which linear polymer chains, P(PEGMA), are crosslinked with each other).

[0045] The crosslinking was performed in a nitrogen atmosphere (O 2 It is preferable to carry out the process in an atmosphere free of oxygen.2 In addition, it is preferable to control the UV irradiation time (or energy) to stop the progress of crosslinking when the second polymer thin film 3 is in a rubbery state (i.e., when the second polymer thin film 3 maintains its entropy elasticity or when functional groups that contribute to the crosslinking reaction remain in the second polymer thin film 3).

[0046] By making the second polymer thin film 3 in a rubbery state, dissolution of the second polymer thin film 3 in water is suppressed when the polymer composite thin film 1 is separated from the substrate in the fifth step described below. That is, by crosslinking P(PEGMA) molecules together, the physical properties of the second polymer thin film 3 are stabilized, and it becomes possible to manufacture the polymer composite thin film 1 including the second polymer thin film 3 without breakage or the like. Furthermore, by stopping the progress of crosslinking in the rubbery state, it becomes possible to ensure the gas permeability of the second polymer thin film 3.

[0047] <4th process> The fourth step is a step of applying and curing a PDMS preparation solution, i.e., a polymeric material-containing solution, so as to cover the cross-linked second polymer thin film 3, to form the first polymer thin film 2. The polymeric material-containing solution (PDMS preparation solution) prepared in the first step is applied by spin coating so as to cover the cross-linked second polymer thin film 3, and is then cured.

[0048] <5th process> The fifth step is a step of dissolving the sacrificial layer and peeling off the polymer composite thin film 1 composed of the first polymer thin film 2 and the second polymer thin film 3 from the substrate. Through the above-mentioned steps, the sacrificial layer, the second polymer thin film 3, and the first polymer thin film 2 are formed on the substrate in that order from the substrate closest to the substrate. The substrate on which the polymer composite thin film 1 is formed is immersed in water, and the sacrificial layer is dissolved in the water, thereby peeling off the polymer composite thin film 1 from the substrate.

[0049] Then, the polymer composite thin film 1 peeled off from the substrate is transferred to a support 5 to obtain a gas separator 6. When transferring, the configuration shown in FIG. 1(a) or the configuration shown in FIG. 1(b) can be selected. As will be described later, in the gas separator 6, the gas separation characteristics differ between when the gas is permeated from the first polymer thin film 2 to the second polymer thin film 3 and when the gas is permeated from the second polymer thin film 3 to the first polymer thin film 2, and the user can select the configuration of the gas separator 6 according to the required characteristics. EXAMPLES

[0050] According to the above process, first, an oxyethylene chain-containing polymer solution was prepared by dissolving P(PEGMA) in ethanol so that the content thereof was 0.05 g / mL and the content of the photopolymerization initiator was 0.0005 g / mL.

[0051] A PDMS preparation solution (polymer material-containing solution) was prepared by dissolving polydimethylsiloxane, hydroxyl-terminated (PDMS) in hexane so that the content was 0.038 g / mL, the content of trimethoxy(methyl)silane was 0.0016 g / mL, and the content of diisopropoxybis(ethylacetoacetate)titanium was 0.0008 g / mL.

[0052] The oxyethylene chain-containing polymer solution prepared by the above-mentioned operation was applied by spin coating (3000 rpm / 1 min) onto a substrate on which a layer (sacrificial layer) of polystyrene sodium sulfonate (hereinafter sometimes referred to as "PSS") was formed. The substrate was then heated at 3000 rpm for 1 min. 2 The substrate was left to stand in the atmosphere for 30 minutes, and then irradiated with UV light in the same atmosphere to form a second polymer thin film 3.

[0053] Next, the PDMS preparation solution prepared by the above-mentioned operation was applied by spin coating (3000 rpm / 1 min) so as to cover the second polymer thin film 3. Thereafter, the substrate was left standing in the air for one day to harden the PDMS and form the first polymer thin film 2.

[0054] Next, the substrate was immersed in water to dissolve the sacrificial layer and peel off the polymer composite thin film 1 from the substrate. Then, the polymer composite thin film 1 was transferred to the support 5 in such an aspect that the first polymer thin film 2 of the polymer composite thin film 1 was in contact with the support 5, thereby obtaining a gas separator 6. EXAMPLES

[0055] A polymer composite thin film 1 and a gas separator 6 were prepared under the same conditions as in Example 1, except that an oxyethylene chain-containing polymer solution was used in which the P(PEGMA) content was 0.04 g / mL and the photopolymerization initiator content was 0.0004 g / mL. EXAMPLES

[0056] A polymer composite thin film 1 and a gas separator 6 were prepared under the same conditions as in Example 1, except that an oxyethylene chain-containing polymer solution was used in which the P(PEGMA) content was 0.03 g / mL and the photopolymerization initiator content was 0.0003 g / mL. EXAMPLES

[0057] A polymer composite thin film 1 and a gas separator 6 were produced under the same conditions as in Example 1, except that an oxyethylene chain-containing polymer solution with a P(PEGMA) content of 0.005 g / mL and a photopolymerization initiator content of 0.00005 g / mL and a PDMS preparation solution with a PDMS content of 0.076 g / mL were used. EXAMPLES

[0058] A polymer composite thin film 1 and a gas separator 6 were produced under the same conditions as in Example 1, except that an oxyethylene chain-containing polymer solution with a P(PEGMA) content of 0.005 g / mL and a photopolymerization initiator content of 0.00005 g / mL and a PDMS preparation solution with a PDMS content of 0.114 g / mL were used. EXAMPLES

[0059] A polymer composite thin film 1 and a gas separator 6 were produced under the same conditions as in Example 1, except that an oxyethylene chain-containing polymer solution with a P(PEGMA) content of 0.01 g / mL and a photopolymerization initiator content of 0.0001 g / mL and a PDMS preparation solution with a PDMS content of 0.2 g / mL were used. (Comparative Example)

[0060] A comparative example will be described below. A PDMS preparation solution was obtained in the same manner as in Example 1. 2 After plasma cleaning, a sacrificial layer was formed by spin-coating (3000 rpm / 1 min) a PSS aqueous solution (15 wt%) onto the substrate, and then the substrate was dried by heating.

[0061] Next, the PDMS preparation solution was applied by spin coating (3000 rpm / 1 min) so as to cover the sacrificial layer. After that, the substrate was left in the air for one day to harden the PDMS. Next, the substrate was immersed in water to dissolve the sacrificial layer and peel the polymer thin film from the substrate. The PDMS thin film was then transferred to a support 5 to obtain a gas separator 6. The polymer thin film of the comparative example may be hereinafter referred to as a "PDMS thin film". The PDMS thin film corresponds to the first polymer thin film 2 described above.

[0062] The following table 1 shows the presence or absence of self-supporting ability, the thickness of the first polymer thin film 2, the thickness of the second polymer thin film 3, and the amount of CO 2 Transparency, N 2 Transparency, O 2 Permeability, selectivity ratio CO 2 / N 2 , O 2 / N 2 , CO 2 / O 2 The film thicknesses of the first polymer thin film 2 and the second polymer thin film 3 are the results of producing multiple gas separators 6 under the same conditions and observing the cross section of the polymer composite thin film 1 with a scanning electron microscope (SEM), and the gas permeability is the result of a gas permeability test in which gas is passed through the gas separator 6 in the order of the second polymer thin film 3 and then the first polymer thin film 2 (the same applies to [Table 3], [Table 4], and [Table 5]). Here, 1 GPU = 3.35 x 10-10 mol m -2 ·s -1 ·Pa -1 It is.

[0063] The gas permeability test is specifically conducted using CO 2 Gas, N 2 Gas, and O 2 The gases were individually fed to the gas separator 6, which had a membrane area of ​​0.785 cm 2 The volume of the liquid that permeated the second polymer thin film 3 and the first polymer thin film 2 was measured by a soap film flowmeter.

[0064] [Table 1]

[0065] As shown in [Table 1], the polymer composite thin film 1 of Examples 1 to 6 and the comparative example all have self-supporting properties. The presence or absence of self-supporting properties is judged based on the criterion of whether or not the thin film (film) can maintain its flat membrane shape without breaking or the like by itself even when the film floating in the liquid is pulled up into the air after being peeled off from the substrate in the stripping liquid. In other words, if the film structure is maintained without breaking even in the air, it is judged to be "self-supporting," and if the film structure is maintained while floating in the stripping liquid after peeling, but easily breaks when taken out into the air, it is judged to be "not self-supporting."

[0066] In Examples 1 to 3, the thickness of the first polymer thin film 2 containing PDMS is almost the same as that of the PDMS thin film of the comparative example, and it can be considered that the second polymer thin film 3 is superimposed on the PDMS thin film of the comparative example. The thinner the second polymer thin film 3, the higher the gas permeability. However, by superimposing the second polymer thin film 3 on the first polymer thin film 2, the thickness of the polymer composite thin film 1 also increases, which results in the increase in the amount of CO 2 , N 2 , O 2 The permeability is lower than that of the comparative example. However, the gas selectivity is 2 / N 2 is significantly improved compared to the comparative example, and O 2 / N2 is also found to be improved.

[0067] Furthermore, the second polymer thin film 3 containing P(PEGMA), i.e., oxyethylene chains, is very soft and fragile when used alone. However, as shown in Examples 4 to 6, by overlapping with the first polymer thin film 2, the second polymer thin film 3 can be made very thin (20 nm or less). This ensures the independence of the entire film, enabling it to exhibit high gas selectivity. EXAMPLES

[0068] A polymer composite thin film 1 and a gas separator 6 were produced under the same conditions as in Example 1, except that an oxyethylene chain-containing polymer solution with a P(PEGMA) content of 0.03 g / mL and a photopolymerization initiator content of 0.0003 g / mL and a PDMS preparation solution with a PDMS content of 0.076 g / mL were used. EXAMPLES

[0069] A polymer composite thin film 1 and a gas separator 6 were produced under the same conditions as in Example 1, except that an oxyethylene chain-containing polymer solution with a P(PEGMA) content of 0.03 g / mL and a photopolymerization initiator content of 0.0003 g / mL and a PDMS preparation solution with a PDMS content of 0.114 g / mL were used. EXAMPLES

[0070] A gas separator 6 was produced under the same conditions as in Example 7, except that the polymer composite thin film 1 was transferred to the support 5 in such a manner that the second polymer thin film 3 of the polymer composite thin film 1 was in contact with the support 5. EXAMPLES

[0071] A gas separator 6 was produced under the same conditions as in Example 8, except that the polymer composite thin film 1 was transferred to the support 5 in such a manner that the second polymer thin film 3 of the polymer composite thin film 1 was in contact with the support 5.

[0072] Table 2 below shows the presence or absence of self-supporting ability, the thickness of the first polymer thin film 2, the thickness of the second polymer thin film 3, and the amount of CO 2 Transparency, N 2 Transparency, O 2 Permeability, selectivity ratio CO 2 / N 2 , O 2 / N 2 , CO 2 / O 2 Shows.

[0073] [Table 2]

[0074] Regarding gas permeability, in Examples 7 and 8 in which the second polymer thin film 3 is in contact with the support 5, the gas was allowed to permeate from the second polymer thin film 3 to the first polymer thin film 2 (see FIG. 1(a)), whereas in Examples 9 and 10 in which the first polymer thin film 2 is in contact with the support 5, the gas was allowed to permeate from the first polymer thin film 2 to the second polymer thin film 3 (see FIG. 1(b)). It can be seen from Table 2 that when the gas was allowed to permeate from the second polymer thin film 3 to the first polymer thin film 2, the gas selectivity was superior, whereas when the gas was allowed to permeate from the first polymer thin film 2 to the second polymer thin film 3, the gas permeability was superior.

[0075] Second embodiment 2(a) is an explanatory diagram showing the configuration of a polymer composite thin film 1 and a gas separator 6 including the polymer composite thin film 1 according to a second embodiment of the present invention. In the second embodiment, the components of the gas separator 6 are the same as those in the first embodiment, but the second embodiment differs from the first embodiment in that a reinforcing material 10 is dispersed in the second polymer thin film 3. Here, carbon nanotubes 11 and cellulose nanofibers 12 can be suitably used as the reinforcing material 10. The carbon nanotubes 11 and cellulose nanofibers 12 are high mechanical strength materials, and the second polymer thin film 3 in which they are dispersed exhibits high mechanical strength.

[0076] Either single-walled carbon nanotubes (SWNT) or multi-walled carbon nanotubes (MWNT) may be used as the carbon nanotubes 11 (hereinafter, these may be collectively referred to as "CNTs"). CNTs can form a tube network due to their high aspect ratio (diameter 0.5 to 3 nm, length up to 10 μm for SWNTs, diameter 5 to 100 nm, length up to 20 μm for MWNTs), and their mechanical properties are obtained by a combination of stiffness, strength, and tensile strength.

[0077] The cellulose nanofibers 12 include oxidized cellulose nanofibers, and further, a mixture of cellulose nanofibers 12 and oxidized cellulose nanofibers (hereinafter, these may be collectively referred to as "CNF") may be used as the organic polymer. CNF forms fibrils, which are small fibers (fibrous structures). Fibrils have high mechanical strength as a material, and by dispersing the reinforcing material 10 made of CNF in the second polymer thin film 3, it is possible to achieve extremely high overall mechanical strength. In addition, CNF is manufactured at low cost by mechanical defibration from abundant resources such as wood, and is an environmentally friendly material since it is a plant fiber.

[0078] CNTs and CNFs preferably have a diameter smaller than the thickness of the polymer composite thin film 1 (for example, up to 200 nm), more preferably have a diameter smaller than the thickness of the second polymer thin film 3 in the first embodiment described above (for example, up to 70 nm), and even more preferably have a diameter smaller than the thickness of the second polymer thin film 3 in the second embodiment (for example, up to 35 nm). By selecting CNTs and CNFs with a diameter smaller than the thickness of the polymer composite thin film 1, the mechanical strength is improved and the functionality (here, gas permeability and gas selectivity) of the polymer composite thin film 1 as a whole is exhibited. In addition, by using CNTs and CNFs with a diameter smaller than the thickness of the second polymer thin film 3 (or the first polymer thin film 2), the functionality of the second polymer thin film 3 (first polymer thin film 2) is fully exhibited. (The same applies to the third and fourth embodiments.)

[0079] In FIG. 2(a) (also in FIG. 2(b) and FIG. 2(c)), the reinforcing material 10 having the same fiber length is shown aligned in a specific direction, but this is merely a schematic illustration. The lengths of the CNTs and CNFs vary, and they are further oriented in all directions and entangled (tube network or fiber network) and are included in the second polymer thin film 3 (the first polymer thin film 2 in FIG. 2(b) and the reinforcing layer 4 in FIG. 2(c) (hereinafter, these may be collectively referred to as the "thin film / layer"). However, by adjusting the amount of CNTs and CNFs added, the distribution of the CNTs and CNFs is limited (controlled) so that the network density in the thin film / layer is extremely sparse. This makes it possible to prevent a decrease in the functionality (particularly the permeability here) of the polymer composite thin film 1.

[0080] In a sparse network in terms of density, in plane A thereof, in the thickness direction of the thin film / layer, there are a first region A1 where a plurality of reinforcing materials 10 exist, a second region A2 where a single reinforcing material 10 exists, and a third region A3 where no reinforcing material 10 is present, and they are mixed. This can also be rephrased as having, in a part of the plane formed by the thin film / layer, in the thickness direction of the thin film / layer, a region where a plurality of reinforcing materials 10 do not overlap with each other. Further, when the area of the first region A1 is S1, the area of the second region A2 is S2, and the area of the third region A3 is S3, the thin film / layer is configured such that S1 < S2 < S3. Here, when the ratio of S3 in plane A is defined as the porosity, it is preferable that the porosity exceeds 90%.

[0081] Hereinafter, the manufacturing process of the polymer composite thin film 1 and the gas separator 6 including the polymer composite thin film 1 in the second embodiment will be described. <First Step> This is a step of preparing an oxyethylene chain-containing polymer-reinforcing material-containing solution containing an oxyethylene chain-containing polymer and a reinforcing material 10, and preparing a polymer material-containing solution containing a polymer material having a selective permeability for a predetermined gas when made into a thin film.

[0082] Similar to the first step of the first embodiment, to the powder of P(PEGMA), a photopolymerization initiator of 1 wt% with respect to P(PEGMA) is added, and this is dissolved in a predetermined amount of ethanol to prepare an oxyethylene chain-containing polymer solution. When using carbon nanotubes 11 as the reinforcing material 10, the carbon nanotubes 11 are dispersed in ethanol to prepare a CNT dispersion.

[0083] On the other hand, when using cellulose nanofibers 12 as the reinforcing material 10, the cellulose nanofibers 12 are dispersed in ethanol to prepare a CNF dispersion. At this time, it is preferable to prepare the CNF dispersion so that there are no aggregates that would cause film defects during thin film production.

[0084] The above-mentioned oxyethylene chain-containing polymer solution is mixed with a CNT dispersion or a CNF dispersion to prepare an oxyethylene chain-containing polymer-reinforcement-containing solution containing an oxyethylene chain-containing polymer and a reinforcing material 10. Note that the "step of preparing a polymer material-containing solution containing a polymer material having selective permeability to a predetermined gas when formed into a thin film" is the same as the first step described in the first embodiment, and therefore a description thereof will be omitted.

[0085] <Second process> The second step is a step of forming a second polymer thin film 3 by applying a solution containing an oxyethylene chain-containing polymer and a reinforcing material onto the substrate on which the sacrificial layer has been formed so as to cover the sacrificial layer. As in the second step of the first embodiment, a sacrificial layer made of PSS is formed on the substrate. Next, the solution containing an oxyethylene chain-containing polymer and a reinforcing material prepared in the first step is applied so as to cover the sacrificial layer, forming the second polymer thin film 3. After that, the second polymer thin film 3 is heated in N 2 Keep it in the atmosphere.

[0086] By using spin coating when applying the oxyethylene chain-containing polymer-reinforcing material-containing solution, a strong external force acts on the reinforcing material 10 contained in the solution, and the carbon nanotubes 11 or cellulose nanofibers 12 contained in the reinforcing material 10 cannot form a three-dimensional tube (fiber) network, i.e., in the thickness direction of the film. As a result, the reinforcing material 10 is swept away by the solvent (ethanol in this case) and arranged on a flat surface, forming a substantially two-dimensional tube (fiber) network (the sparse network described above).

[0087] <3rd process ~ 5th process> The third step is a step of crosslinking the second polymer thin film 3, the fourth step is a step of applying and curing a polymer material-containing solution so as to cover the crosslinked second polymer thin film 3 to form the first polymer thin film 2, and the fifth step is a step of dissolving the sacrificial layer and peeling the polymer composite thin film 1 composed of the first polymer thin film 2 and the second polymer thin film 3 from the substrate. These steps are the same as the third to fifth steps described in the first embodiment, so the description is omitted. Then, the polymer composite thin film 1 peeled off from the substrate is transferred to the support 5 to obtain the gas separator 6. As described in the first embodiment, the first polymer thin film 2 may be configured to contact the support 5 when transferring, or the second polymer thin film 3 may be configured to contact the support 5. EXAMPLES

[0088] 1 g of P(PEGMA) powder and 0.01 g of photopolymerization initiator were dissolved in ethanol to prepare an oxyethylene chain-containing polymer solution with a P(PEGMA) content of 0.01 g / mL and a photopolymerization initiator content of 0.0001 g / mL. Further, a CNT dispersion was added to the oxyethylene chain-containing polymer solution to prepare an oxyethylene chain-containing polymer-reinforcement material-containing solution containing 0.00003 g / mL of carbon nanotubes 11. Separately from this, a PDMS preparation solution was prepared in the same manner as in Example 1.

[0089] Next, a sacrificial layer was formed on the substrate using PSS in the same manner as in Example 1. Furthermore, the oxyethylene chain-containing polymer-reinforcing material-containing solution prepared by the above-mentioned operation was applied by spin coating onto the substrate on which the sacrificial layer was formed. The substrate on which the oxyethylene chain-containing polymer-reinforcing material-containing solution was applied was then heated at 300° C. for 1 hour. 2 The mixture was allowed to stand in the atmosphere for 30 minutes.

[0090] Thereafter, UV irradiation was performed in the same atmosphere to crosslink the oxyethylene chain-containing polymer-reinforcing material-containing layer, thereby forming a second polymer thin film 3. Note that, also in Example 4, the progress of crosslinking was stopped when the second polymer thin film 3 was in a rubbery state by controlling the UV irradiation time.

[0091] Next, the PDMS preparation solution prepared by the above-mentioned operation was applied by spin coating (3000 rpm / 1 min) so as to cover the second polymer thin film 3. Thereafter, the substrate was left standing in the air for one day to harden the PDMS and form the first polymer thin film 2.

[0092] Next, the substrate was immersed in water to dissolve the sacrificial layer and peel off the polymer composite thin film 1 from the substrate. Then, similarly to Example 1, the polymer composite thin film 1 was transferred to the support 5 in such an embodiment that the first polymer thin film 2 of the polymer composite thin film 1 was in contact with the support 5, thereby obtaining a gas separator 6. EXAMPLES

[0093] A polymer composite thin film 1 and a gas separator 6 were produced under the same conditions as in Example 11, except that an oxyethylene chain-containing polymer-reinforcing material-containing solution containing 0.000015 g / mL of carbon nanotubes 11 was used. EXAMPLES

[0094] A polymer composite thin film 1 and a gas separator 6 were produced under the same conditions as in Example 11, except that an oxyethylene chain-containing polymer-reinforcing material-containing solution containing 0.0000039 g / mL of carbon nanotubes 11 was used. EXAMPLES

[0095] 0.5 g of P(PEGMA) powder and 0.005 g of photopolymerization initiator were dissolved in ethanol to prepare an oxyethylene chain-containing polymer solution with a P(PEGMA) concentration of 0.03 g / mL and a photopolymerization initiator content of 0.0003 g / mL. Furthermore, a CNF dispersion was added to the oxyethylene chain-containing polymer solution to prepare an oxyethylene chain-containing polymer-reinforcement material-containing solution containing 0.00024 g / mL of cellulose nanofibers 12. A PDMS preparation solution was prepared separately from this in the same manner as in Example 1.

[0096] Next, a sacrificial layer was formed on the substrate using PSS in the same manner as in Example 1, and a second polymer thin film 3 was formed on the sacrificial layer using an oxyethylene chain-containing polymer-reinforcement-containing solution in the same manner as in Example 11, and the progress of crosslinking was stopped in the rubber state. Furthermore, a first polymer thin film 2 was formed using a PDMS preparation solution so as to cover the second polymer thin film 3. Next, the polymer composite thin film 1 composed of the second polymer thin film 3 and the first polymer thin film 2 was peeled off from the sacrificial layer. Then, the polymer composite thin film 1 was transferred to the support 5 in the same manner as in Example 1, and a gas separator 6 was obtained.

[0097] Table 3 below shows the results of Examples 11 to 14 regarding the presence or absence of self-supporting ability, the thickness of the first polymer thin film 2, the thickness of the second polymer thin film 3, the amount of reinforcing material 10 added to the second polymer thin film 3, and the amount of CO 2 Transparency, N 2 Transparency, O 2 Permeability, selectivity ratio CO 2 / N 2 , O 2 / N 2 , CO 2 / O 2 Table 3 also shows data for comparative examples. [Table 3]

[0098] As shown in Table 3, the polymer composite thin films 1 of Examples 11 to 14 all have self-supporting properties. In all cases, the thickness of the first polymer thin film 2 containing PDMS is almost the same as that of the PDMS thin film of the comparative example, and the polymer composite thin films 1 of Examples 11 to 14 can be considered to be structured such that the second polymer thin film 3 containing the reinforcing material 10 is superimposed on the PDMS thin film of the comparative example.

[0099] By overlapping the second polymer thin film 3 on the first polymer thin film 2, the total film thickness also increases. 2 , N 2 , O 2 The transmittance is lower than that of the comparative example. On the other hand, in Examples 12 and 13, the CO2 The permeability exceeds 10,000 GPU, which is comparable to the comparative example. 2 / N 2 is significantly improved compared to the comparative example, and O 2 / N 2 is also found to be improved.

[0100] Here, in Examples 11 to 13, carbon nanotubes 11 are added to the second polymer thin film 3. Comparing this with Examples 1 to 3 (wherein the second polymer thin film 3 does not include a reinforcing material 10), the film thickness of the second polymer thin film 3 is 38 nm in Examples 11 to 13, and the film thickness of the second polymer thin film 3 is 113 nm to 74 nm in Examples 1 to 3. That is, in Examples 11 to 13, the addition of carbon nanotubes 11 as the reinforcing material 10 to the second polymer thin film 3 improves the mechanical strength, and it is possible to configure the second polymer thin film 3 (and as a result, the polymer composite thin film 1) to be thinner.

[0101] In Example 14, cellulose nanofibers 12 were added to the second polymer thin film 3. The thickness of the second polymer thin film 3 in Example 14 was 74 nm, which is the same as the thickness of the second polymer thin film 3 in Example 3. The cellulose nanofibers 12 added to the second polymer thin film 3 functioned as a barrier to prevent CO 2 Although it is believed that the permeability will decrease (5459 GPU in Example 3 and 3586 GPU in Example 14), it is clear that the cellulose nanofibers 12 improve the mechanical strength of the second polymer thin film 3, and the configuration of Example 14 can be suitably used, for example, in cases where there is a large difference in air pressure between the upstream and downstream sides of the gas separator 6.

[0102] Third embodiment FIG. 2(b) is an explanatory diagram showing the configuration of a polymer composite thin film 1 and a gas separator 6 including the polymer composite thin film 1 according to the third embodiment of the present invention. In the third embodiment, the components of the gas separator 6 are the same as those in the first embodiment, but the third embodiment differs from the first and second embodiments in that a reinforcing material 10 is dispersed in the first polymer thin film 2. As in the second embodiment, CNT and CNF can be suitably used as the reinforcing material 10. The first polymer thin film 2 in which CNT or CNF is dispersed exhibits extremely high mechanical strength. In particular, by selecting CNT or CNF with a diameter smaller than the thickness of the first polymer thin film 2, the functionality of the first polymer thin film 2 is fully exhibited. Note that in the first polymer thin film 2 as well, the reinforcing material 10 forms the above-mentioned sparse network.

[0103] Hereinafter, a manufacturing process of the polymer composite thin film 1 and the gas separator 6 including the polymer composite thin film 1 in the third embodiment will be described. <1st process> This is a process of preparing an oxyethylene chain-containing polymer solution containing an oxyethylene chain, and preparing a polymer material-reinforcement containing solution containing a polymer material and a reinforcing material 10 that has selective permeability to a predetermined gas when formed into a thin film.

[0104] As in the first step of the first embodiment, a photopolymerization initiator is added to P(PEGMA) powder at 1 wt % relative to P(PEGMA), and this is dissolved in a predetermined amount of ethanol to prepare an oxyethylene chain-containing polymer solution.

[0105] A CNT dispersion (or a CNF dispersion) and a polymer material-containing solution (a PDMS preparation solution) are prepared in the same manner as in the second embodiment. The above-mentioned polymer material-containing solution is mixed with a CNT dispersion or a CNF dispersion to prepare a polymer material-reinforcement-containing solution that contains a polymer material (here, PDMS) and a reinforcing material 10.

[0106] <2nd process, 3rd process> The second step is a step of applying an oxyethylene chain-containing polymer solution onto the substrate on which the sacrificial layer has been formed so as to cover the sacrificial layer, thereby forming a second polymer thin film 3. The third step is a step of crosslinking the second polymer thin film 3. The second and third steps are the same as those in the first embodiment, and therefore a description thereof will be omitted.

[0107] <4th process> This is a process in which a solution containing a polymer material and a reinforcing material is applied and cured so as to cover the crosslinked second polymer thin film 3, thereby forming a first polymer thin film 2. The solution containing a polymer material and a reinforcing material prepared in the first process is applied so as to cover the crosslinked second polymer thin film 3. Thereafter, the first polymer thin film 2 is cured by leaving it in the air for one day.

[0108] <5th process> This is a step in which the sacrificial layer is dissolved, and the polymer composite thin film 1 composed of the first polymer thin film 2 and the second polymer thin film 3 is peeled off from the substrate. The fifth step is the same as in the first embodiment, and therefore a description thereof will be omitted. The polymer composite thin film 1 peeled off from the substrate is transferred to a support 5, thereby obtaining a gas separator 6. EXAMPLES

[0109] An oxyethylene chain-containing polymer solution was prepared with a P(PEGMA) content of 0.01 g / mL and a photopolymerization initiator content of 0.0001 g / mL in the same manner as in Example 11. A PDMS preparation solution was separately prepared in the same manner as in Example 1. Furthermore, a CNT dispersion was added to the PDMS preparation solution to prepare a polymer material-reinforcement material-containing solution containing 0.000015 g / mL of carbon nanotubes 11.

[0110] Next, a sacrificial layer was formed on the substrate using PSS in the same manner as in Example 1. Furthermore, the oxyethylene chain-containing polymer solution prepared by the above-mentioned operation was applied by spin coating onto the substrate on which the sacrificial layer was formed. The substrate on which the oxyethylene chain-containing polymer solution was applied was then heated at 3000 K for 1 hour at 400° C. for 24 hours. 2 The substrate was left to stand in the atmosphere for 30 minutes, and then irradiated with UV light in the same atmosphere to crosslink the oxyethylene chain-containing polymer, thereby forming a second polymer thin film 3.

[0111] Next, the polymer material-reinforcing material-containing solution prepared by the above-mentioned operation was applied by spin coating (3000 rpm / 1 min) so as to cover the second polymer thin film 3. Thereafter, the substrate was left to stand in the air for one day, and the polymer material-reinforcing material-containing solution was hardened to form the first polymer thin film 2. Next, the substrate was immersed in water to dissolve the sacrificial layer and peel off the polymer composite thin film 1 from the substrate. Then, the polymer composite thin film 1 was placed on the support 5 in the same manner as in Example 1, and a gas separator 6 was obtained. EXAMPLES

[0112] An oxyethylene chain-containing polymer solution was prepared with a P(PEGMA) content of 0.03 g / mL and a photopolymerization initiator content of 0.0003 g / mL in the same manner as in Example 3. A PDMS preparation solution was prepared separately from this in the same manner as in Example 1. Furthermore, a CNF dispersion was added to the PDMS preparation solution to prepare a polymer material-reinforcement material-containing solution containing 0.0000004 g / mL of cellulose nanofibers 12. The other conditions were the same as in Example 15, and a polymer composite thin film 1 and a gas separator 6 were obtained. EXAMPLES

[0113] A polymer composite thin film 1 and a gas separator 6 were obtained in the same manner as in Example 16, except that an oxyethylene chain-containing polymer solution having a P(PEGMA) content of 0.01 g / mL and a photopolymerization initiator content of 0.0001 g / mL was used as the oxyethylene chain-containing polymer solution.

[0114] Table 4 below shows the results of Examples 15 to 17 with or without self-supporting ability, the thickness of the first polymer thin film 2, the thickness of the second polymer thin film 3, the amount of reinforcing material 10 added to the first polymer thin film 2, and the amount of CO 2 Transparency, N 2 Transparency, O 2 Permeability, selectivity ratio CO 2 / N 2 , O 2 / N 2 , CO 2 / O 2Table 4 also shows data for comparative examples. [Table 4]

[0115] As shown in Table 4, all of the polymer composite thin films 1 of Examples 15 to 17 are self-supporting. In all cases, the thickness of the first polymer thin film 2 containing PDMS is almost the same as that of the PDMS thin film of the comparative example, and the polymer composite thin films 1 of Examples 15 to 17 can be considered to be structurally the PDMS thin film of the comparative example to which the reinforcing material 10 has been added and to which the second polymer thin film 3 has been superimposed.

[0116] By superposing the second polymer thin film 3 on the first polymer thin film 2 including PDMS and the reinforcing material 10, the overall film thickness also increases. 2 , N 2 , O 2 The permeability is lower than that of the comparative example. On the other hand, the gas selectivity is 2 / N 2 is significantly improved compared to the comparative example, and O 2 / N 2 is also found to be improved.

[0117] Here, in Example 15, carbon nanotubes 11 are added to the first polymer thin film 2, and in Example 17, cellulose nanofibers 12 are added to the first polymer thin film 2. Compared with Examples 1 to 3 (in which the first polymer thin film 2 does not include a reinforcing material 10), the film thickness of the second polymer thin film 3 is 38 nm in Examples 15 and 17, and the film thickness of the second polymer thin film 3 is 113 nm to 74 nm in Examples 1 to 3. That is, in Examples 15 and 17, the second polymer thin film 3 is supported by the first polymer thin film 2 including the reinforcing material 10, thereby improving the overall mechanical strength, and it is possible to configure the second polymer thin film 3 (and as a result, the polymer composite thin film 1) to be thinner.

[0118] (Fourth embodiment) FIG. 2(c) is an explanatory diagram showing the configuration of a polymer composite thin film 1 and a gas separator 6 including the polymer composite thin film 1 according to the fourth embodiment of the present invention. In the fourth embodiment, the gas separator 6 is composed of a polymer composite thin film 1 and a support 5. The polymer composite thin film 1 is composed of a first polymer thin film 2, a reinforcing layer 4, and a second polymer thin film 3, and the reinforcing layer 4 is provided between the first polymer thin film 2 and the second polymer thin film 3. Here, the reinforcing layer 4 is composed of a reinforcing material 10 such as carbon nanotubes 11 and cellulose nanofibers 12. That is, the fourth embodiment differs from each of the other embodiments in that the reinforcing layer 4 composed of the reinforcing material 10 is provided independently. The carbon nanotubes 11 and the cellulose nanofibers 12 have high mechanical strength as materials, and the reinforcing layer 4 composed of these exhibits extremely high mechanical strength, thereby improving the strength of the entire polymer composite thin film 1. In the reinforcing layer 4, the reinforcing material 10 also forms the above-mentioned sparse network.

[0119] In the fourth embodiment, the configurations of the first polymer thin film 2, the second polymer thin film 3, and the support 5 are similar to those in the first embodiment, and therefore the description thereof will be omitted. Hereinafter, a manufacturing process of the polymer composite thin film 1 and the gas separator 6 including the polymer composite thin film 1 in the fourth embodiment will be described. <1st process> This is a process for preparing a reinforcing material dispersion liquid containing a reinforcing material 10, an oxyethylene chain-containing polymer solution containing an oxyethylene chain, and a polymer material-containing solution containing a polymer material that has selective permeability to a predetermined gas when formed into a thin film.

[0120] As in the first step of the first embodiment, 1 wt% of a photopolymerization initiator relative to P(PEGMA) is added to the powder of P(PEGMA) and dissolved in a predetermined amount of ethanol to prepare an oxyethylene chain-containing polymer solution. As in the second embodiment, a CNT dispersion or a CNF dispersion (hereinafter, these may be collectively referred to as "reinforcement dispersion") and a polymer material-containing solution (PDMS preparation solution) are prepared.

[0121] <2nd process, 3rd process> The second step is a step of applying an oxyethylene chain-containing polymer solution onto the substrate on which the sacrificial layer has been formed so as to cover the sacrificial layer, thereby forming a second polymer thin film 3. The third step is a step of crosslinking the second polymer thin film 3. The second and third steps are the same as those in the first embodiment, and therefore a description thereof will be omitted.

[0122] <4th process> This is a process in which a reinforcing material dispersion is applied so as to cover the cross-linked second polymer thin film 3, thereby forming a reinforcing layer 4. When forming the reinforcing layer 4, the reinforcing material dispersion prepared in the first process is applied so as to cover the cross-linked second polymer thin film 3.

[0123] <5th process> This is a step in which a polymer material-containing solution is applied and cured so as to cover the reinforcing layer 4, thereby forming the first polymer thin film 2. The polymer material-containing solution (PDMS preparation solution) prepared in the first step is applied so as to cover the reinforcing layer 4, thereby forming the first polymer thin film 2. Thereafter, the first polymer thin film 2 is left to stand in the air for one day, and the first polymer thin film 2 is cured.

[0124] <6th process> This is a process in which the sacrificial layer is dissolved to peel the polymer composite thin film 1 from the substrate. On the substrate, a sacrificial layer, a second polymer thin film 3, a reinforcing layer 4, and a first polymer thin film 2 are formed in that order from the substrate's side, which constitute the polymer composite thin film 1. The substrate is immersed in water to dissolve the sacrificial layer in the water, thereby peeling the polymer composite thin film 1 from the substrate. The polymer composite thin film 1 peeled from the substrate is then transferred to a support 5, thereby obtaining a gas separator 6.

[0125] In the fourth embodiment, the reinforcing layer 4 may be formed after the sacrificial layer is formed (fourth step), and then the second polymer thin film 3 may be formed and crosslinked by applying an oxyethylene chain-containing polymer solution so as to cover the reinforcing layer 4 (second and third steps), and the first polymer thin film 2 may be formed by applying a PDMS preparation solution so as to cover the second polymer thin film 3 (fifth step) to produce the polymer composite thin film 1. The gas separator 6 may be configured so that the reinforcing layer 4 and the support 5 constituting the polymer composite thin film 1 are in contact with each other, or the gas separator 6 may be configured so that the first polymer thin film 2 and the support 5 are in contact with each other. EXAMPLES

[0126] An oxyethylene chain-containing polymer solution was prepared with a P(PEGMA) content of 0.01 g / mL and a photopolymerization initiator content of 0.0001 g / mL in the same manner as in Example 11. Separately from this, a PDMS preparation solution was prepared in the same manner as in Example 1. Furthermore, a reinforcing material dispersion solution containing 0.00003 g / mL of carbon nanotubes 11 was prepared.

[0127] Next, a sacrificial layer was formed on the substrate using PSS in the same manner as in Example 1. Furthermore, the oxyethylene chain-containing polymer solution prepared by the above-mentioned operation was applied by spin coating (3000 rpm, 1 min) onto the substrate on which the sacrificial layer was formed. Then, the substrate on which the oxyethylene chain-containing polymer solution was applied was heated at 3000° C. for 1 min. 2 The substrate was left to stand in the atmosphere for 30 minutes, and then irradiated with UV light in the same atmosphere to crosslink the P(PEGMA) and form a second polymer thin film 3.

[0128] Next, the reinforcing material dispersion liquid prepared by the above-mentioned operation was applied by spin coating (3000 rpm / 1 min) so as to cover the second polymer thin film 3, forming a reinforcing layer 4. Next, the PDMS preparation liquid prepared by the above-mentioned operation was applied by spin coating (3000 rpm / 1 min) so as to cover the reinforcing layer 4. Thereafter, the substrate was left to stand in the air for one day, and the PDMS was cured to form a first polymer thin film 2. In this way, a sacrificial layer and a polymer composite thin film 1 were formed on the substrate.

[0129] Next, the substrate was immersed in water to dissolve the sacrificial layer and peel off the polymer composite thin film 1 from the substrate. Then, the polymer composite thin film 1 was transferred to the support 5 in such an aspect that the first polymer thin film 2 of the polymer composite thin film 1 was in contact with the support 5, thereby obtaining a gas separator 6. When the cross section of the polymer composite thin film 1 was observed by SEM, the reinforcing layer 4 could not be clearly identified. EXAMPLES

[0130] A polymer composite thin film 1 and a gas separator 6 were produced under the same conditions as in Example 18, except that a reinforcing material dispersion containing 0.000015 g / mL of carbon nanotubes 11 was used. In Example 19, too, the reinforcing layer 4 could not be clearly identified in SEM observation of the cross section of the polymer composite thin film 1. EXAMPLES

[0131] A polymer composite thin film 1 and a gas separator 6 were produced under the same conditions as in Example 18, except that a reinforcing material dispersion containing 0.0006 g / mL of cellulose nanofibers 12 was used. In Example 20, when the cross section of the polymer composite thin film 1 was observed by SEM, the reinforcing layer 4 could not be clearly identified.

[0132] Table 5 below shows the results of Examples 18 to 20 with and without self-supporting ability, the thickness of the first polymer thin film 2, the thickness of the second polymer thin film 3, the material constituting the reinforcing layer 4, the amount of the reinforcing material 10 added, and the amount of CO 2 Transparency, N 2 Transparency, O 2 Permeability, selectivity ratio CO 2 / N 2 , O 2 / N 2 , CO 2 / O 2 The data for comparative examples are also shown in [Table 5]. [Table 5]

[0133] As shown in [Table 5], all of the polymer composite thin films 1 of Examples 18 to 20 are self-supporting. In all cases, the thickness of the first polymer thin film 2 containing PDMS is almost the same as that of the PDMS thin film of the comparative example, and the polymer composite thin films 1 of Examples 18 to 20 can be considered to be structured such that the reinforcing material 10 is unevenly distributed on one surface of the PDMS thin film of the comparative example, and the second polymer thin film 3 is superimposed on this.

[0134] By superposing the second polymer thin film 3 on the first polymer thin film 2 including PDMS and the reinforcing material 10, the overall film thickness also increases. 2 , N 2 , O 2 The permeability is lower than that of the comparative example. On the other hand, the gas selectivity is 2 / N 2 is significantly improved compared to the comparative examples, and except for Example 20, 2 / N 2 is also found to be improved.

[0135] Here, in Examples 18 and 19, the reinforcing layer 4 is made of carbon nanotubes 11, and in Example 20, the reinforcing layer 4 is made of cellulose nanofibers 12. Compared with Examples 1 to 3 (in which the first polymer thin film 2 and the second polymer thin film 3 do not include the reinforcing material 10), the film thickness of the second polymer thin film 3 is 38 nm in Examples 18 and 19, and the film thickness of the second polymer thin film 3 is 113 nm to 74 nm in Examples 1 to 3. That is, in Examples 18 and 19, the first polymer thin film 2 including the reinforcing layer 4 supports the second polymer thin film 3, thereby improving the overall mechanical strength, and it is possible to configure the second polymer thin film 3 (and as a result, the polymer composite thin film 1) to be thinner.

[0136] In the gas separators 6 of the second to fourth embodiments, as explained in the first embodiment (Examples 7 to 10), the gas selectivity was superior when the gas was permeated from the second polymer thin film 3 to the first polymer thin film 2, whereas the gas permeability was superior when the gas was permeated from the first polymer thin film 2 to the second polymer thin film 3.

[0137] As described above, according to the first to fourth embodiments, a polymer composite thin film 1 having a good balance of gas permeability and gas selectivity is realized by combining two polymer thin films with different properties, or further combining (composite) a reinforcing material 10, or combining a reinforcing layer 4.

[0138] Fifth embodiment Fig. 3 is an explanatory diagram showing the configuration of a gas separation apparatus 110 including a gas separator 6 according to the present invention. As shown in Fig. 3, the gas separation apparatus 110 is composed of a blower 114, a prefilter 111, a dust collecting filter 112, and a gas separator 6, and an air flow path 119 is formed from an intake port 115 to a first outlet 116a (and a second outlet 116b).

[0139] The blower 114 is configured by, for example, an air compressor. When the blower 114 is driven, air is sucked in from an inlet 115, and passes through a flow path 119 as an air flow AF, passing through the pre-filter 111, the dust collecting filter 112, and the gas separator 6 in this order.

[0140] The air that has permeated the gas separator 6 is discharged as an air flow AFO from a first outlet 116a provided downstream of the gas separator 6. On the other hand, the air that has not permeated the gas separator 6 is discharged as an air flow AFN from a second outlet 116b provided upstream of the gas separator 6.

[0141] Here, in order to perform gas separation, a pressure difference is required between the upstream space (first space S1) and the downstream space (here, the external space S0) sandwiching the gas separator 6. In the gas separation device 110 of the fifth embodiment, in order to secure the pressure difference, an air cock 117 is connected to the second blowing port 116b to restrict the outflow amount of the air flow AFN, and compressed air is sent out by the blower 114 to adjust the first space S1 to a positive pressure with respect to the external space S0 (1 atmosphere). In addition, for those of the polymer composite thin films 1 mounted on the gas separator 6 that have high permeability, the air pressure in the first space S1 can be set to a gentle value, for example, about 2 atmospheres (pressure difference between the first space S1 and the external space S0 = 1 atmosphere). Furthermore, since the polymer composite thin film 1 according to the present invention has very high gas selectivity, it can efficiently separate gas even if the pressure difference before and after the gas separator 6 is small.

[0142] Furthermore, the polymer composite thin film 1 according to the present invention (particularly the second to fourth embodiments) has extremely high mechanical strength because it is configured to include the reinforcing material 10 in the polymer composite thin film 1. For this reason, it is possible to set the pressure difference between the first space S1 and the external space S0 high, at about 10 atmospheres.

[0143] The pre-filter 111 is a filter through which the air sucked by the blower 114 first passes, and collects relatively large dust particles contained in the airflow AF. The dust collection filter 112 is a filter through which the air that has passed through the pre-filter 111 next passes, and a HEPA (High Efficiency Particulate Air) filter, for example, is preferably used.

[0144] The gas separator 6 is provided therein with the polymer composite thin film 1 described in the first to fourth embodiments. The gas supply unit (here, the blower 114) supplies gas so that the gas permeates through the second polymer thin film 3 and then the first polymer thin film 2 (or through the first polymer thin film 2 and then the second polymer thin film 3). This allows the user of the gas separation apparatus 110 to select a configuration of the gas separator 6 with better gas selectivity or gas permeability to obtain oxygen-enriched air, carbon dioxide-enriched air, or nitrogen-enriched air.

[0145] As shown in Tables 1 to 5, the polymer composite thin film 1 according to the present invention is 2 Compared to CO 2 and O 2 Since the permeability of the air is high, the air flow AFO that passes through the gas separator 6 and is discharged from the first outlet 116a has a higher O2 content than normal air. 2 and CO 2 On the other hand, the airflow AFN discharged from the second outlet 116b without passing through the gas separator 6 has a higher nitrogen concentration than normal air (i.e., nitrogen-enriched air).

[0146] Airflow AFO is a method to measure the amount of CO in air. 2 Since the carbon dioxide enriched air is concentrated in the atmosphere, the gas separation device 110 captures the carbon dioxide enriched air. 2 In the gas separator 6, the polymer composite membrane 1 may be provided in series in a multi-stage configuration. 2 / N 2 When the selectivity is set to 2.2, and the number of stages of the polymer composite thin film 1 is set to P, the total O 2 / N 2 The selectivity is 2.2^P, and it is possible to increase the oxygen concentration by increasing the number of stages. Of course, when P is increased, the total gas permeability in the gas separator 6 decreases. In this case, it is possible to deal with this by increasing the capacity of the air compressor that constitutes the blower 114.

[0147] For example, in "Polymer Journal (2021) 53:111-119 A new strategy for membrane-based direct air capture," the inventors described that by configuring the polymer thin film in the gas separator 6 in multiple stages, it is possible to effectively capture CO 2 It has been reported that the gas separation device 110 with multi-stage polymer membranes can be installed in various sizes and scales, and new CO 2 The polymer composite thin film 1 according to the present invention has high permeability, extremely high gas selectivity, and extremely high mechanical strength, and therefore can be used to recover CO 2 Or O 2 This is extremely useful for concentrating and recovering.

[0148] Furthermore, the airflow AFO is used in fish farms that use oxygen-enriched air, oxygen combustion power plants, oxygen combustion boilers, etc. 2 The concentration is also increasing, but it can be reduced by passing the airflow AFO through activated carbon or water, for example. 2 It is relatively easy to remove CO 2 It is possible to obtain large amounts of oxygen-enriched air with reduced increase in concentration.

[0149] On the other hand, airflow AFN can be used for fire extinguishing, for example. Three elements are necessary for combustion: combustibles, oxygen supplier, and ignition source. In air, combustion of combustibles will not continue unless the oxygen concentration is above the critical limit. If the nitrogen concentration is above 85% (oxygen concentration is below 14%), the combustion of most combustibles can be suppressed. Furthermore, airflow AFN (nitrogen-enriched air) can be used in corrosion and decay prevention systems (preservation systems) that prevent the deterioration of food, artworks, etc. due to oxidation.

[0150] In addition, in thermal power plants where fossil fuels such as coal, oil, and LNG gas are burned in boilers and the heat produced by the combustion creates steam that turns turbines to generate electricity, AFO (oxygen-enriched air) airflow is normally used to improve combustion efficiency, while in the event that the boiler becomes abnormally hot due to a malfunction, AFN (nitrogen-enriched air) airflow can be supplied to prevent fires.

[0151] In addition to the air described above, the air flow AFO may be exhaust gas from an internal combustion engine or other mixed gases. In this case, the exhaust gas or other mixed gases can be enriched with carbon dioxide, oxygen, or nitrogen.

[0152] Among polysiloxanes, PDMS is known to have a particularly large free volume ratio. In fact, the cavity radius inside the polymer estimated by positron annihilation spectroscopy is said to be less than 1 nm (see Yampolskii, Pinnau, Freeman, 2006 John Wiley & Sons, Ltd "Materials Science of Membranes for Gas and Vapor Separation" p.125). Therefore, so-called nanoparticles that exceed this size have difficulty penetrating the PDMS membrane, and the airflow AFO becomes clean air that does not contain nanoparticles.

[0153] In this way, the gas separation device 110 equipped with the polymer composite thin film 1 of the present invention not only has high permeability, selectivity, and mechanical strength, but also has the function of removing nano-sized particles that cannot be removed even by the above-mentioned dust collection filter 112.By applying the polymer composite thin film 1, it is possible to realize a clean room system (air purifier) ​​with extremely high levels of cleanliness.

[0154] The polymer composite membrane 1 and gas separation device 110 according to the present invention have been described above based on specific embodiments and examples, but these are merely examples and the present invention is not limited to these embodiments and examples. [Industrial Applicability]

[0155] The polymer composite membrane 1 according to the present invention has high gas permeability, gas selectivity, and mechanical strength, and the gas separation device 110 equipped with the polymer composite membrane 1 has high gas separation properties. 2 Carbon dioxide capture and storage (CCS) is used to separate and capture CO from the source, such as power plants and factories, and CO from the air is also used. 2 This can be suitably applied to DAC that directly recovers [Explanation of symbols]

[0156] 1 Polymer composite thin film 2. First polymer thin film 3. Second polymer thin film 4 Reinforcement layer 5 Support 6 Gas separator 10 Reinforcement 11 Carbon nanotubes 12 Cellulose nanofiber 110 Gas separation equipment 114 Blower

Claims

1. a first polymer thin film having selective permeability to a predetermined gas; a second polymer thin film that is provided so as to overlap the first polymer thin film and that contains at least an oxyethylene chain; A polymer composite thin film, characterized in that the thickness of the second polymer thin film is less than 100 nm, and the total thickness of the first polymer thin film and the second polymer thin film is 20 nm to 1350 nm. (However, this does not include the case where the first polymer thin film or the second polymer thin film is a porous film.)

2. 2. The polymer composite thin film according to claim 1, wherein carbon nanotubes or cellulose nanofibers are dispersed in the second polymer thin film.

3. 2. The polymer composite thin film according to claim 1, wherein carbon nanotubes or cellulose nanofibers are dispersed in the first polymer thin film.

4. 2. The polymer composite thin film according to claim 1, further comprising a reinforcing layer formed of carbon nanotubes or cellulose nanofibers between the first polymer thin film and the second polymer thin film.

5. 5. The polymer composite thin film according to claim 1, wherein the second polymer thin film is composed of a crosslinked polymer containing an oxyethylene chain.

6. 5. The polymer composite thin film according to claim 1, wherein the second polymer thin film has a thickness such that the second polymer thin film does not have self-supporting properties by itself.

7. The polymer composite membrane according to any one of claims 1 to 4, wherein the second polymer membrane has a higher CO2 / N2 selectivity than the first polymer membrane.

8. The polymer composite thin film according to any one of claims 1 to 4, characterized in that the second polymer thin film maintains entropy elasticity.

9. 5. The polymer composite thin film according to claim 1, which selectively allows carbon dioxide and oxygen to permeate from air, exhaust gas, and other mixed gases.

10. The polymer composite thin film according to any one of claims 1 to 4, wherein the first polymer thin film contains polysiloxane.

11. A polymer composite thin film according to any one of claims 1 to 4, A gas separator comprising: a support for supporting the polymer composite thin film.

12. The gas separator according to claim 11 ; a gas supply unit that supplies a gas to the gas separator; Equipped with The gas separation apparatus, wherein the gas supplying section supplies gas so that the gas permeates through the second polymer thin film and then the first polymer thin film in that order.

13. The gas separator according to claim 11 ; a gas supply unit that supplies a gas to the gas separator; Equipped with The gas separation apparatus, wherein the gas supplying section supplies gas so that the gas permeates through the first polymer thin film and then the second polymer thin film in that order.

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