A flow cell for preparing a monodisperse microporous membrane and a preparation method thereof.

Abstract

This invention relates to a flow cell and a preparation method for preparing a microporous membrane with monodisperse channels. The flow cell includes a film-forming chamber, which comprises a sheet-like cavity, with a porous membrane disposed on one side of the sheet-like cavity extending in the direction of extension. The preparation method is as follows: S1, prepare the flow cell and a monodisperse microsphere solution; S2, under pressure, inject the monodisperse microsphere solution into the flow cell, where the microspheres accumulate within the sheet-like cavity of the film-forming chamber, forming a sheet-like stacked structure; S3, inject the solution into the flow cell under pressure; S4, form a membrane to obtain a spherical membrane composite material; S5, remove the microspheres, thus completing the preparation of the microporous membrane. This invention utilizes a flow cell for preparation, allowing microspheres to gradually accumulate along the sheet-like extension direction within the flow cell. The prepared microporous membrane has a stable structure, adjustable thickness, number of layers, and pore size, and a consistent pore size distribution. The preparation method is simple and easy to implement. The prepared microporous membrane can be used as a base membrane for chromatography, effectively improving the separation performance and efficiency of the chromatography membrane.

Description

Technical Field

[0001] This invention relates to the field of microporous membranes, and in particular to a flow cell and preparation method for preparing microporous membranes with monodisperse channels. Background Technology

[0002] Chromatographic membranes are functionalized porous polymer films with wide applications in the separation and purification of biomolecules. The preparation of chromatographic membranes involves the preparation and functionalization of microporous base membranes. The pore size and distribution of the base membrane play a decisive role in macromolecular mass transfer. Currently used chromatographic base membranes are characterized by inconsistent pore sizes and uneven size distribution. The main preparation method for chromatographic base membranes is the phase inversion method, including vapor-induced phase separation and solvent-induced phase inversion. By adjusting the type of solvent and the composition of the non-solvent phase, the type and concentration of the pore-forming agent, and the membrane preparation process, the pore size and porosity can be adjusted, but it is difficult to achieve a monodisperse pore structure with uniform vertical distribution. Track etching can prepare uniform cylindrical pores with narrow pore distribution on polymer films, but due to the limitations of the pore-forming mechanism of this method, the thickness of the porous membranes formed is generally difficult to exceed 30 μm, and they can only have a single-layer pore structure, thus greatly limiting the specific surface area. Therefore, developing microporous filter membranes with monodisperse pore size and high specific surface area has great practical value for improving the separation performance and efficiency of chromatography membranes. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a flow cell and preparation method for preparing microporous membranes with monodisperse channels. The flow cell employs a design where a porous membrane is positioned on one side of the extending direction of a sheet-like cavity, allowing microspheres to gradually accumulate along the sheet's extension direction. Using this flow cell for microporous membrane preparation results in a stable microporous membrane structure with adjustable thickness, number of layers, and pore size, exhibiting a consistent pore size distribution. Furthermore, the preparation method is simple and easy to implement. The prepared microporous membrane can be used as a base membrane in chromatography, effectively improving the separation performance and efficiency of the chromatography membrane.

[0004] The technical solution adopted by this invention to solve its technical problem is:

[0005] A flow cell for preparing a microporous membrane with monodisperse channels includes a film-forming chamber, the film-forming chamber including at least a sheet-like cavity corresponding to the microporous membrane to be prepared, the outlet of the film-forming chamber being disposed on one side of the extending direction of the sheet-like cavity, and a porous membrane being disposed at the outlet of the film-forming chamber.

[0006] A method for preparing a microporous membrane with monodisperse channels, specifically comprising the following steps:

[0007] S1. Prepare the flow cell and uniformly disperse the monodisperse microspheres in the solvent to form a monodisperse microsphere solution;

[0008] S2. Under pressure, the monodisperse microsphere solution prepared in S1 is injected into the film-forming chamber of the flow cell. Under pressure, the solvent of the monodisperse microsphere solution slowly permeates through the porous membrane and is discharged, causing the microspheres to accumulate in the sheet-like cavity of the film-forming chamber, forming a sheet-like stacked structure. The thickness of the sheet-like stacked structure corresponds to the thickness of the sheet-like cavity of the film-forming chamber in the flow cell.

[0009] S3. Prepare the casting solution and inject it into the flow cell under pressure to wet the sheet-like stacked structure formed by the microspheres, so that the gaps between the microspheres in the sheet-like stacked structure are filled by the casting solution.

[0010] S4. Obtain a spherical film composite material through a film-forming process;

[0011] S5. Perform microsphere removal treatment on the spherical membrane composite material to obtain a microporous membrane with monodisperse channels.

[0012] In step S1, the solvent can also be replaced by the casting solution in S3, that is, the monodisperse microspheres are uniformly dispersed in the casting solution; after the treatment in step S2, the process proceeds directly to step S4.

[0013] In step S2, the microspheres accumulate in the sheet-like cavity of the film-forming chamber from the porous membrane away from the porous membrane. Under the thickness limitation of the forming cavity, they gradually lengthen to form a sheet-like accumulation structure.

[0014] The number of pore layers in a microporous membrane is controlled by adjusting the thickness of the sheet-like cavity in the flow cell and the particle size of the microspheres used.

[0015] In step S4, the film-forming process is a film-forming process of the casting solution, which includes, but is not limited to: cooling, photocrosslinking, thermal crosslinking, chemical crosslinking, and phase separation.

[0016] In step S5, the microsphere removal process is a method for removing microspheres from the spherical film composite material, which includes, but is not limited to: solvent dissolution to remove microspheres, and calcination to remove microspheres.

[0017] An application of a microporous membrane with monodisperse channels is that the microporous membrane prepared by the above method is used as a base membrane in chromatography.

[0018] Advantages of this invention: The present invention provides a flow cell and preparation method for preparing microporous membranes with monodisperse channels. The flow cell is designed with a porous membrane on one side of the extending direction of the sheet-like cavity, allowing microspheres to gradually accumulate along the extending direction of the sheet. Using this flow cell to prepare microporous membranes results in a stable microporous membrane structure with adjustable thickness, number of layers, and pore size, and a consistent pore size distribution. Furthermore, the preparation method is simple and easy to implement. The prepared microporous membrane can be used as a base membrane for chromatography, effectively improving the separation performance and efficiency of the chromatography membrane. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a flow cell used to prepare a microporous membrane with monodisperse channels, as an example.

[0020] Figure 2 Electron microscopy image of the 5 μm monodisperse SiO2 microspheres used in Example 1;

[0021] Figure 3 The surface electron microscope image of the spherical film composite material in Example 1;

[0022] Figure 4 Electron microscopy image of the surface of the microporous membrane prepared in Example 1;

[0023] Figure 5 A cross-sectional electron microscope image of the microporous membrane prepared in Example 1;

[0024] Wherein, 1-sheet-like cavity, 2-porous membrane. Detailed Implementation

[0025] To enhance understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0026] Example

[0027] Please refer to Figure 1 As shown, this embodiment provides a flow cell for preparing a microporous membrane with monodisperse channels, including a film-forming chamber. The film-forming chamber includes at least a sheet-like cavity 1 corresponding to the microporous membrane to be prepared. The outlet of the film-forming chamber is located on one side of the extending direction of the sheet-like cavity 1. A porous membrane 2 is also provided at the outlet of the film-forming chamber 1.

[0028] This embodiment also provides a method for preparing a microporous membrane with monodisperse channels, which is carried out according to the following steps:

[0029] S1. Prepare the flow cell and uniformly disperse the monodisperse microspheres in the solvent to form a monodisperse microsphere solution.

[0030] S2. Under pressure, the monodisperse microsphere solution prepared in S1 is injected into the film-forming chamber of the flow cell. Under pressure, the solvent of the monodisperse microsphere solution slowly permeates through the porous membrane and is discharged, causing the microspheres to accumulate in the sheet-like cavity of the film-forming chamber, forming a sheet-like stacked structure. The thickness of the sheet-like stacked structure corresponds to the thickness of the sheet-like cavity of the film-forming chamber in the flow cell.

[0031] S3. Prepare the casting solution and inject it into the flow cell under pressure to wet the sheet-like stacked structure formed by the microspheres, so that the gaps between the microspheres in the sheet-like stacked structure are filled by the casting solution.

[0032] S4. Obtain a spherical film composite material through a film-forming process;

[0033] S5. Perform microsphere removal treatment on the spherical membrane composite material to obtain a microporous membrane with monodisperse channels.

[0034] In one embodiment of this method for preparing a microporous membrane with monodisperse channels, the pore size of the porous membrane is smaller than the particle size of the microspheres, and the solvent is allowed to pass through.

[0035] In one embodiment of the preparation method for preparing a microporous membrane with monodisperse channels, the flow cell is a filterable type, which not only helps the monodisperse microspheres to quickly form a densely packed structure, but also maintains the corresponding densely packed structure, so that the densely packed structure is in a stable state in subsequent processing steps (film formation process).

[0036] In one embodiment of the preparation method for preparing a microporous membrane with monodisperse channels, there are many types of materials used to form the membrane, such as polysulfone, polyethersulfone, cellulose acetate, polyolefin, polymethacrylate, etc.

[0037] In a method for preparing a microporous membrane with monodisperse channels according to this embodiment, in step S1, the solvent can be replaced with the casting solution of S3, that is, the monodisperse microspheres are uniformly dispersed in the casting solution; after step S2, the process proceeds directly to step S4.

[0038] In a method for preparing a microporous membrane with monodisperse channels according to this embodiment, in step S2, the microspheres are gradually stacked in the sheet-like cavity of the film-forming chamber from the porous membrane away from the porous membrane. Under the thickness limitation of the forming cavity, they gradually lengthen to form a sheet-like stacking structure.

[0039] In one embodiment of the preparation method for preparing a microporous membrane with monodisperse channels, the number of pore layers of the microporous membrane is controlled by controlling the thickness of the sheet-like cavity of the film-forming chamber of the flow cell and the particle size of the microspheres used.

[0040] In a method for preparing a microporous membrane with monodisperse channels according to this embodiment, in step S4, the film-forming process is a film-forming process of a casting solution, which includes, but is not limited to: cooling, photocrosslinking, thermal crosslinking, chemical crosslinking, and phase separation.

[0041] In a method for preparing a microporous membrane with monodisperse channels according to this embodiment, in step S5, the microsphere removal treatment is a method for removing microspheres from the spherical membrane composite material, which includes, but is not limited to: solvent dissolution to remove microspheres, and calcination to remove microspheres.

[0042] This embodiment also provides an application of a microporous membrane with monodisperse channels. The microporous membrane prepared by the above method can be used as a base membrane in chromatography membranes.

[0043] This embodiment describes a flow cell and preparation method for preparing a microporous membrane with monodisperse channels. The flow cell is designed with a porous membrane on one side of the extending direction of the sheet-like cavity, allowing microspheres to gradually accumulate along the extending direction of the sheet. Using this flow cell to prepare the microporous membrane results in a stable microporous membrane structure with adjustable thickness, number of layers, and pore size, and a consistent pore size distribution. Furthermore, the preparation method is simple and easy to implement. The prepared microporous membrane can be used as a base membrane in chromatography, effectively improving the separation performance and efficiency of the chromatography membrane.

[0044] The present invention will be further described in detail below with reference to preparation examples.

[0045] Manufacturing Example 1:

[0046] Two g of monodisperse SiO2 microspheres with a particle size of 5 μm and 16 g of polysulfone polymer were uniformly dispersed in 82 g of NMP solvent to obtain a mixed solution. A polypropylene filter membrane with a pore size of 0.22 μm was selected as the porous membrane and installed at the outlet end of a flow cell with a sheet-like cavity thickness of 100 μm. Under a pressure of 3 bar, the aforementioned mixed solution was injected into the flow cell, allowing the mixed solution to slowly pass through the porous membrane. The flow was stopped when the solution that had passed through occupied approximately 95% of the initial volume. The porous membrane was carefully removed, and the flow cell was immersed in water until the membrane in the flow cell turned completely white, thus obtaining the polysulfone and SiO2 microsphere spherical membrane composite material. Then, the membrane was immersed in an aqueous solution of 5% HF for 10 h, removed, and rinsed with clean water to obtain a polysulfone microporous membrane with monodisperse channels.

[0047] Manufacturing Example 2

[0048] Two g of monodisperse SiO2 microspheres with a particle size of 5 μm were dispersed in an ethanol solution to obtain a monodisperse microsphere solution. A polypropylene filter membrane with a pore size of 0.22 μm was selected as the porous membrane and installed at the outlet of a flow cell with a sheet-like cavity thickness of 200 μm. Under a pressure of 0.5 bar, the aforementioned monodisperse microsphere solution was slowly injected into the flow cell until all the ethanol permeated through the porous membrane under pressure. An 8% (w / w) mixed solution of cellulose diacetate in CH2Cl2 / ethanol was slowly injected into the flow cell under a pressure of 1 bar until the solution began to permeate through the porous membrane relatively continuously. After carefully removing the porous membrane, the flow cell was placed in an environment with H2O vapor at a relative humidity of 70% until the entire membrane turned white, thus obtaining the spherical membrane composite material of cellulose diacetate and SiO2 microspheres. Then, the membrane is immersed in an aqueous solution of 5% HF for 10 hours, removed, and rinsed with clean water to obtain a monodisperse cellulose diacetate microporous membrane.

[0049] Manufacturing Example 3

[0050] Two g of monodisperse SiO2 microspheres with a particle size of 5 μm were dispersed in an ethanol solution to obtain a monodisperse microsphere solution. A polypropylene filter membrane with a pore size of 0.22 μm was selected as the porous membrane and installed at the outlet of a flow cell with a sheet-like cavity thickness of 200 μm. Under a pressure of 0.5 bar, the aforementioned monodisperse microsphere solution was slowly injected into the flow cell until all the ethanol permeated through the porous membrane under pressure. Potassium sulfonyl methacrylate, ethylene glycol dimethacrylate monomer, and initiator were dissolved in a mixed solvent of NMP / H2O. After complete dissolution, the solution was slowly injected into the flow cell until the solution began to permeate through the porous membrane relatively continuously. After carefully removing the porous membrane, the flow cell was placed in an oven at 80°C and heated for 6 hours to obtain a spherical membrane composite material of potassium sulfonyl methacrylate and ethylene glycol dimethacrylate crosslinked polymer and SiO2 spheres. Then, after repeatedly soaking and cleaning the spherical membrane composite material with deionized water, the membrane is immersed in an aqueous solution of HF with a mass percentage of 5% for 10 hours, taken out, and rinsed with clean water to obtain a microporous membrane with monodisperse channels.

[0051] In Example 1, electron microscopy was used to examine the surface of the 5 μm monodisperse SiO2 microspheres, the surface of the fabricated spherical film composite material, and the surface and cross-section of the fabricated microporous membrane; respectively, the results were obtained. Figures 2 to 5 ;from Figure 2 Monodisperse SiO2 microspheres can be clearly observed in the sample; from Figure 3 In the process, it was clearly observed that the distribution of microspheres in the spherical film composite material formed in the flow cell was very uniform; from Figure 4 In the study, it was clearly observed that the microporous membrane obtained after removing the microspheres from the spherical membrane composite material exhibited a uniform pore size distribution; from Figure 5In the test results, it was clearly observed that the cross-section of the microporous membrane had a multi-layered pore structure. These test results demonstrate that the present invention has essentially completed the preparation of a microporous membrane with monodisperse pores.

[0052] The above embodiments should not limit the present invention in any way. All technical solutions obtained by equivalent substitution or equivalent conversion fall within the protection scope of the present invention.

Claims

1. A method for preparing a microporous membrane with monodisperse channels, characterized in that: The membrane is prepared using a flow cell, wherein the flow cell includes a film-forming chamber, the film-forming chamber includes at least a sheet-like cavity corresponding to the microporous membrane to be prepared, the outlet of the film-forming chamber is located on one side of the extending direction of the sheet-like cavity, and a porous membrane is also provided at the outlet of the film-forming chamber. The preparation method is carried out according to the following steps: S1. Prepare the flow cell; uniformly disperse monodisperse microspheres in a solvent to form a monodisperse microsphere solution; S2. Under pressure, the monodisperse microsphere solution prepared in S1 is injected into the film-forming chamber of the flow cell. Under pressure, the solvent of the monodisperse microsphere solution slowly permeates through the porous membrane and is discharged, causing the microspheres to accumulate in the sheet-like cavity of the film-forming chamber, forming a sheet-like stacked structure. The thickness of the sheet-like stacked structure corresponds to the thickness of the sheet-like cavity of the film-forming chamber in the flow cell. S3. Prepare the casting solution and inject it into the flow cell under pressure to wet the sheet-like stacked structure formed by the microspheres, so that the gaps between the microspheres in the sheet-like stacked structure are filled by the casting solution. S4. Obtain a spherical film composite material through a film-forming process; S5. Perform microsphere removal treatment on the spherical membrane composite material to obtain a microporous membrane with monodisperse channels.

2. The method for preparing a microporous membrane with monodisperse channels according to claim 1, characterized in that: In step S1, the solvent is replaced by the casting solution of S3, that is, the monodisperse microspheres are uniformly dispersed in the casting solution; after the treatment in step S2, the process proceeds directly to step S4.

3. The method for preparing a microporous membrane with monodisperse channels according to claim 1, characterized in that: In step S2, the accumulation of microspheres in the sheet-like cavity of the film-forming chamber is a gradual accumulation from the porous membrane away from the porous membrane. Under the thickness limitation of the film-forming cavity, the microspheres gradually lengthen to form a sheet-like accumulation structure.

4. The method for preparing a microporous membrane with monodisperse channels according to claim 1, characterized in that: The number of pore layers in a microporous membrane is controlled by adjusting the thickness of the sheet-like cavity in the flow cell and the particle size of the microspheres used.

5. The method for preparing a microporous membrane with monodisperse channels according to claim 1, characterized in that: In step S4, the film-forming process is a film-forming process of the casting solution, which includes, but is not limited to: cooling, photocrosslinking, thermal crosslinking, chemical crosslinking, or phase separation.

6. The method for preparing a microporous membrane with monodisperse channels according to claim 1, characterized in that: In step S5, the microsphere removal treatment is a method for removing microspheres from the spherical film composite material, which includes, but is not limited to: solvent dissolution to remove microspheres or calcination to remove microspheres.

7. An application of a microporous membrane with monodisperse channels, characterized in that: Application of microporous membranes prepared by any one of the preparation methods described in claims 1-6 as base membranes in chromatography membranes.

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