Rigid porous polymer membranes based on confined reaction microenvironment regulation and applications thereof

Abstract

This invention relates to the field of polymer materials and membrane separation technology, and discloses a rigid porous polymer membrane based on the control of a confined reaction microenvironment and its applications. The rigid porous polymer membrane includes a substrate and a rigid porous polymer separation layer loaded on the surface of the substrate. The rigid porous polymer separation layer is formed by confined polymerization reaction in a confined reaction microenvironment. The preparation method of the rigid porous polymer separation layer includes: constructing a confined reaction microenvironment; preparing a reaction precursor solution; introducing the reaction precursor into the confined reaction microenvironment to undergo a confined polymerization reaction; and obtaining a rigid porous polymer membrane after washing and drying. This invention suppresses disordered explosive polymerization by controlling the reaction diffusion coupling behavior, and achieves the controllable preparation of ultrathin, continuous, dense and low-defect-rate rigid porous polymer membranes. The prepared rigid porous polymer membranes are applied in the fields of organic solvent nanofiltration, crude oil separation, gas separation, pervaporation, and selective sieving of small molecules.

Description

Technical Field

[0001] This invention relates to the field of polymer materials and membrane separation technology, specifically to rigid porous polymer membranes based on the regulation of confined reaction microenvironment and their applications. Background Technology

[0002] Rigid porous polymers are a class of permanent porous network materials formed by the cross-linking polymerization of multifunctional rigid organic monomers. They possess high specific surface area, regular microporous structure, and excellent chemical stability, and have broad application prospects in fields such as organic solvent nanofiltration, gas separation, catalytic separation, and molecular sieving. Conjugated microporous polymers (CMPs), as a typical representative, can be constructed through reactions such as Sonogashira-Hagihara coupling, Suzuki-Miyaura coupling, Yamamoto coupling, Buchwald-Hartwig coupling, and Scholl oxidative coupling.

[0003] However, due to the highly cross-linked, insoluble, and infusible properties of rigid porous polymers, it is difficult to prepare continuous films using traditional solution processing methods. Currently, methods such as template methods, in-situ deposition methods, and interfacial polymerization are mainly used for film formation, but the resulting films generally suffer from problems such as difficulty in controlling thickness, poor continuity, high defect rate, and insufficient repeatability.

[0004] Research has revealed that the aforementioned problems primarily stem from the excessively rapid diffusion rate of reactants in open systems, leading to a rapid increase in local concentration and inducing explosive polymerization, resulting in particle aggregation and uncontrolled membrane structure. Specifically: while traditional interfacial polymerization can form thin layers, the reaction is confined to the two-phase interface, making monomer diffusion difficult to precisely control and prone to localized excessive thickness or defects; the thickness of membranes obtained by template methods is limited by the template structure, and the template removal process easily introduces additional defects; in in-situ deposition methods, reactants randomly nucleate and grow on the substrate surface, making continuous two-dimensional spreading difficult. Furthermore, existing methods are typically limited to specific coupling reaction systems or specific materials, lacking the ability to universally control different monomers, catalysts, and acid / alkali environments, and are mainly targeted at specific separation scenarios (such as crude oil separation), making it difficult to extend to other separation fields.

[0005] To address the shortcomings of existing technologies, this invention provides a rigid porous polymer membrane based on the regulation of a confined reaction microenvironment and its applications. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a rigid porous polymer membrane based on the regulation of a confined reaction microenvironment and its applications. It has the advantages of actively regulating reaction-diffusion coupling by constructing a confined reaction microenvironment, suppressing disordered explosive polymerization, and achieving controllable preparation of ultrathin continuous dense membrane layers. It solves the problems of difficult thickness control, poor continuity, high defect rate, insufficient repeatability, and poor method universality of rigid porous polymer membranes in existing technologies.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a rigid porous polymer membrane based on the control of a confined reaction microenvironment, wherein the rigid porous polymer membrane comprises a porous substrate and a rigid porous polymer separation layer loaded on the surface of the substrate; The substrate is selected from any one of polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, polyethersulfone, polyacrylonitrile, alumina ceramic membrane or zirconium oxide; The rigid porous polymer layer is prepared by in-situ polymerization in a confined reaction microenvironment. The confined reaction microenvironment is constructed by pre-wetting or coating the surface of the porous substrate with a physical confinement layer of 1 μm-1000 μm thickness. The confinement layer is composed of at least one selected from liquid film layer, gel layer or polymer coating, and is used to regulate the diffusion rate of reaction precursors during polymerization.

[0008] Preferably, the rigid porous polymer separation layer is a conjugated microporous polymer.

[0009] Preferably, the confined reaction microenvironment is a spatially confined region capable of limiting the diffusion of reaction precursors and regulating local concentration gradients.

[0010] Preferably, the above-mentioned rigid porous polymer membrane includes the following preparation steps: S1. Pretreatment: The support substrate is ultrasonically cleaned sequentially with deionized water, anhydrous ethanol and acetone, and then dried to obtain a clean substrate. S2. Constructing a confined reaction microenvironment: The pretreated substrate is spread on the first reaction precursor solution containing the catalyst and base, and allowed to stand to form a confined liquid film layer. S3. Preparation of reaction precursor solution: Prepare a second reaction precursor solution containing rigid organic monomers; S4, confined polymerization reaction: The second reaction precursor solution prepared in S3 is introduced into the confined reaction microenvironment constructed in S2 to carry out the confined polymerization reaction; S5. Post-treatment: The products after the confined polymerization reaction are washed and dried sequentially with organic solvents to obtain a rigid porous polymer membrane.

[0011] Preferably, the pretreatment conditions in S1 are: ultrasonic cleaning time of 30 min for each; and drying treatment of placing the sample in a 60℃ forced-air drying oven for 12 h.

[0012] Preferably, the confined reaction microenvironment in S2 includes at least one of a liquid film layer, a gel layer, a template pore layer, a capillary pore layer, and an interface wetting layer, and the construction conditions for the confined reaction microenvironment are as follows: (1) When a liquid film layer is used, a confined liquid film layer is formed by spreading the substrate on the surface of the first reaction precursor solution and letting it stand at room temperature for 30 min; or a liquid film layer of a limited thickness is constructed by using a doctor blade. (2) When using a gel layer, a confined gel layer with a thickness of 10 to 100 μm is constructed using polyvinyl alcohol or other hydrogels; The thickness of the finally prepared confined reaction microenvironment was 1–100 μm; The first reaction precursor solution is prepared according to the selected polymerization reaction type and is selected from one of the following combinations: (1) For the Sonogashira-Hagihara coupling reaction: Triethylamine, Pd(PPh3)4 and CuI were added to deionized water and magnetically stirred for 15-60 min under nitrogen protection at room temperature to obtain a clear solution; (2) For the Suzuki-Miyaura coupling reaction: Pd(PPh3)4 and alkali are dissolved in DMF or toluene; (3) For the Yamamoto coupling reaction: Ni(COD)2 is dissolved in DMF.

[0013] Preferably, in step S3, the reaction precursor solution is prepared by dissolving a rigid organic monomer in an anhydrous organic solvent and magnetically stirring for 15–60 min under nitrogen protection at room temperature to obtain a second reaction precursor solution. The rigid organic monomer is selected from at least two aromatic or heterocyclic monomers having a rigid core and at least two terminal reactive groups. The rigid core is selected from one or more of substituted or unsubstituted benzene, biphenyl, terphenyl, naphthalene, anthracene, pyrene, triazine, spirodifluorene, or porphyrin structures. The terminal reactive groups are selected from one or more of halogen groups, terminal alkynyl groups, borate groups, or borate ester groups. The organic solvent is selected from one of anhydrous toluene, DMF, THF, NMP, DMSO, or 1,4-dioxane.

[0014] Preferably, the reaction conditions in S4 are as follows: the polymerization reaction includes at least one of Sonogashira-Hagihara coupling, Suzuki-Miyaura coupling, Yamamoto coupling, Buchwald-Hartwig coupling, and Scholl oxidative coupling; the thickness of the confined reaction microenvironment is 1–100 μm; the polymerization reaction temperature is 60–90 °C; the polymerization reaction time is 6–12 h; and the entire reaction is carried out under nitrogen protection.

[0015] Preferably, the combination of the rigid organic monomers is selected from any of the following: (1) Coupling type: selected from at least two of 1,3,5-triethynylbenzene, 1,4-diethynylbenzene, 1,4-dibromobenzene, 1,3,5-tribromobenzene, 4,4'-biphenyl diboronic acid, 4,4'-dibromobiphenyl, tetra(4-bromophenyl)methane, and 2,4,6-tris(4-bromophenyl)-1,3,5-triazine; (2) Oxidative coupling type: Aromatic monomers containing aryl hydrogen, preferably monomers containing carbazole or benzene skeleton.

[0016] Preferably, the organic solvent washing is performed sequentially using one or more of tetrahydrofuran, anhydrous ethanol, and acetone, with each type of washing performed three times for 10 minutes each time; followed by vacuum drying at 60°C for 12 hours, resulting in a rigid porous polymer film with a thickness of 10 nm to 100 μm, and the film layer is uniform and continuous without obvious pinhole defects.

[0017] Applications of rigid porous polymer membranes based on the restricted reaction microenvironment regulation: The rigid porous polymer membranes prepared according to the above steps are applied in the fields of organic solvent nanofiltration, crude oil separation, gas separation, pervaporation and selective sieving of small molecules.

[0018] Compared with the prior art, the present invention provides a rigid porous polymer membrane based on the control of a confined reaction microenvironment and its applications, which has the following beneficial effects: 1. This invention constructs a confined reaction microenvironment to actively regulate the diffusion path and local concentration gradient of reactants, suppressing rapid burst bulk polymerization in open systems, and enabling the polymerization reaction to preferentially grow continuously along the two-dimensional direction, thereby significantly improving the density and continuity of the membrane layer, reducing the membrane defect rate, and obtaining an ultrathin and structurally controllable rigid porous polymer membrane.

[0019] 2. This invention regulates the membrane growth pathway by controlling the interaction between the substrate surface and specific substances (including reactants, catalysts, or chemicals that provide an acid / base environment). The method is not limited to a single coupling reaction system or a single material type, and is applicable to a variety of coupling reactions and a variety of rigid porous polymers. It has platform versatility, and the preparation process is simple, reproducible, and easy to scale up industrially.

[0020] 3. The rigid porous polymer membrane prepared by the present invention through the confined reaction microenvironment has a rigid pore structure and molecular sieving effect, which can achieve efficient retention and selective permeation of small molecules of different molecular weights. It is widely used in fields such as organic solvent nanofiltration, gas separation, crude oil separation, pervaporation and catalytic separation, and is not limited to the above applications. It has excellent separation performance and long-term operational stability.

[0021] 4. This invention utilizes a microenvironment confinement strategy to directly grow nanoscale high-rigidity films in situ on porous polymer substrates. This avoids the cumbersome process of obtaining a separation-selective layer that requires a high-cost, flat, non-porous substrate and fine peeling and transfer steps in traditional methods. This significantly simplifies the preparation process and ultimately reduces the complexity of the process and manufacturing costs.

[0022] 5. The core of this invention lies in utilizing the physical boundary constraints provided by the confinement layer. In conventional open systems, the explosive coupling of rigid monomers leads to three-dimensional disordered stacking to form particles (as shown in Comparative Example 1). However, this invention, through a confined environment with controllable thickness, restricts the average diffusion path of monomers to the submicron scale. By controlling the Pelet number (Pe), the polymerization reaction rate and the monomer diffusion rate are matched (Reaction-Diffusion Match), thereby inducing quasi-two-dimensional growth of monomers on the substrate surface, ultimately forming a continuous and defect-free nanofilm. Attached Figure Description

[0023] Figure 1 The images show SEM images and physical photos of the CMP membrane surface obtained in Example 1 of this invention. Figure 2 This is a TEM image of the cross-section of the CMP membrane obtained in Example 1 of the present invention; Figure 3 This is a SEM image of the free polymerization product obtained in Comparative Example 1 of this invention; Figure 4 This is a graph showing the relationship between film thickness variations under different monomer concentrations according to the present invention; Figure 5 This is a test diagram of the membrane separation performance of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Please see Figures 1-5 A rigid porous polymer membrane based on the control of a restricted reaction microenvironment, comprising a porous substrate and a rigid porous polymer separation layer loaded on the surface of the substrate; The substrate is selected from any one of polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, polyethersulfone, polyacrylonitrile, alumina ceramic membrane or zirconium oxide; The rigid porous polymer layer is prepared by in-situ polymerization in a confined reaction microenvironment. The confined reaction microenvironment is constructed by pre-wetting or coating the surface of the porous substrate with a physical confinement layer of thickness 1 μm-1000 μm. The confinement layer is composed of at least one selected from liquid film layer, gel layer or polymer coating, and is used to regulate the diffusion rate of reaction precursors during polymerization.

[0026] The rigid porous polymer separation layer is selected from at least one of conjugated microporous polymers (CMP), porous aromatic framework polymers (PAF), covalent organic framework polymers (COF), COF-derived networks, and intrinsically microporous polymer (PIM) crosslinked networks, preferably conjugated microporous polymers; the thickness of the separation layer is 10-800 nm.

[0027] A confined reaction microenvironment is a spatially confined region that can limit the diffusion of reaction precursors and regulate the local concentration gradient.

[0028] The above-mentioned rigid porous polymer membrane includes the following preparation steps: S1. Pretreatment: The support substrate is ultrasonically cleaned sequentially with deionized water, anhydrous ethanol and acetone, and then dried to obtain a clean substrate. S2. Constructing a confined reaction microenvironment: The pretreated substrate is spread on the first reaction precursor solution containing the catalyst and base, and allowed to stand to form a stable confined liquid film layer. S3. Preparation of reaction precursor solution: Prepare a second reaction precursor solution containing rigid organic monomers; S4, confined polymerization reaction: The second reaction precursor solution prepared in S3 is introduced into the confined reaction microenvironment constructed in S2 to carry out the confined polymerization reaction; S5. Post-treatment: The products after the confined polymerization reaction are washed and dried sequentially with organic solvents to obtain the final rigid porous polymer membrane.

[0029] Specifically, the pretreatment conditions in S1 are as follows: ultrasonic cleaning time is 10 to 60 minutes each; drying treatment is to place in a forced-air drying oven at 40 to 80°C for 6 to 24 hours.

[0030] The advantages are: by limiting the ultrasonic cleaning time and drying conditions, it can effectively remove contaminants and residual solvents from the substrate surface, improve the uniformity of the substrate surface and the accessibility of reactive sites, and provide a clean and uniform interface basis for the stable construction of the subsequent confined reaction microenvironment.

[0031] Specifically, the confined reaction microenvironment in S2 includes at least one of the following: liquid film layer, gel layer, template pore layer, capillary pore layer, and interface wetting layer. The construction conditions for the confined reaction microenvironment are as follows: (1) When a liquid film layer is used, a stable confined liquid film layer is formed by spreading the substrate on the surface of the first reaction precursor solution and letting it stand at room temperature for 15 to 60 minutes; or a liquid film layer of a limited thickness is constructed by using a doctor blade (e.g., a 50 to 200 μm doctor blade). (2) When using a gel layer, a confined gel layer with a thickness of 10 to 100 μm is constructed using polyvinyl alcohol or other hydrogels; The final confined reaction microenvironment has a thickness of 1 nm to 1000 μm, preferably 1 to 100 μm (the film is discontinuous when the thickness is less than 0.5 μm, and the reaction diffusion is hindered and the adhesion decreases when the thickness is greater than 2000 μm). The first reaction precursor solution is prepared according to the selected polymerization reaction type and is selected from one of the following combinations: (1) For the Sonogashira-Hagihara coupling reaction: add triethylamine (5-15 mL), Pd(PPh3)4 (1-10 mol%) and CuI (1-10 mol%) to deionized water (10-30 mL), and magnetically stir for 15-60 min under nitrogen protection at room temperature to obtain a clear solution; (2) For the Suzuki-Miyaura coupling reaction: Dissolve Pd(PPh3)4 (1-10 mol%) and a base (such as K2CO3 or triethylamine) in DMF or toluene; (3) For the Yamamoto coupling reaction: Dissolve Ni(COD)2 (5-15 mol%) in DMF.

[0032] The advantages are: by using at least one of the liquid film layer, gel layer, template pore layer, capillary pore layer or interface wetting layer to construct a confined reaction microenvironment with a thickness of 1nm to 1000μm, it is possible to actively control the diffusion path and local concentration gradient of reactants, suppress the rapid disordered diffusion of reactants in the open system, thereby avoiding explosive polymerization and realizing the controllable transport of reactants to the substrate surface and two-dimensional confined growth.

[0033] Specifically, in S3, the precursor solution is prepared by dissolving a rigid organic monomer in an anhydrous organic solvent and magnetically stirring for 15–60 min under nitrogen protection at room temperature to obtain a second precursor solution. The rigid organic monomer is selected from at least two aromatic or heterocyclic monomers having a rigid core and at least two terminal reactive groups. The rigid core is selected from one or more of substituted or unsubstituted benzene, biphenyl, terphenyl, naphthalene, anthracene, pyrene, triazine, spirodifluorene, or porphyrin structures. The terminal reactive groups are selected from one or more of halogen groups (-Cl, -Br, -I), terminal alkynyl groups (-C≡CH), borate groups [-B(OH)2], or borate ester groups. The organic solvent is selected from anhydrous toluene, DMF, THF, NMP, etc. DMSO, or one of 1,4-dioxane; the total molar concentration of all rigid organic monomers is 0.005–0.05 mmol / mL, and the molar ratio of each monomer is adjusted according to the selected coupling reaction type (e.g., alkynyl to bromoyl molar ratio 1:1–1:1.5); formulations include: 0.10 mmol of 1,3,5-triethynylbenzene and 0.15 mmol of 1,4-dibromobenzene dissolved in 20 mL of anhydrous toluene; or 0.10 mmol of 1,3,5-tribromobenzene and 0.15 mmol of biphenyl diboronic acid dissolved in 20 mL of DMF; or 0.10 mmol of tetrabromobiphenyl dissolved in 20 mL of DMF.

[0034] The advantages are: by selecting aromatic compounds with at least two reactive functional groups as rigid organic monomers and controlling the total molar concentration, the molar ratio of each monomer can be adjusted according to the type of coupling reaction, which can ensure that the reaction system maintains appropriate reactivity and crosslinking density in a confined microenvironment, thereby avoiding local oversaturation nucleation and promoting the formation of a uniform and dense film.

[0035] Specifically, the reaction conditions in S4 are as follows: the polymerization reaction includes at least one of Sonogashira-Hagihara coupling, Suzuki-Miyaura coupling, Yamamoto coupling, Buchwald-Hartwig coupling, and Scholl oxidative coupling; the thickness of the confined reaction microenvironment (confined liquid film layer) is 1 nm to 1000 μm; the polymerization reaction temperature is 20 to 150 °C; the polymerization reaction time is 0.5 to 24 h; the reaction is carried out under nitrogen protection (e.g., nitrogen is purged for 5 to 15 min to remove air), and the reaction vessel is a high-pressure reactor or sealed flask lined with polytetrafluoroethylene.

[0036] The advantages are: by controlling the polymerization reaction temperature, time and nitrogen protection environment, and adapting to different coupling reaction types, the reaction kinetics are precisely controlled in a confined microenvironment, so that the polymerization reaction preferentially grows along the two-dimensional direction rather than the three-dimensional bulk agglomeration, thereby obtaining a continuous, dense and low-defect rigid porous polymer membrane.

[0037] Specifically, the combination of rigid organic monomers can be selected from any of the following: (1) Coupling type: selected from at least two of 1,3,5-triethynylbenzene, 1,4-diethynylbenzene, 1,4-dibromobenzene, 1,3,5-tribromobenzene, 4,4'-biphenyl diboronic acid, 4,4'-dibromobiphenyl, tetra(4-bromophenyl)methane, and 2,4,6-tris(4-bromophenyl)-1,3,5-triazine; (2) Oxidative coupling type: Aromatic monomers containing aryl hydrogen, preferably monomers containing carbazole or benzene skeleton.

[0038] Specifically, the organic solvent washing process involves one or more of tetrahydrofuran, anhydrous ethanol, and acetone, with each solvent being washed 1 to 3 times for 5 to 30 minutes each time. The drying conditions are: vacuum drying at 40 to 120°C for 6 to 24 hours. The resulting rigid porous polymer membrane has a thickness of 10 nm to 100 μm, and the membrane layer is uniform and continuous without obvious pinhole defects.

[0039] The advantages are: washing and vacuum drying can effectively remove unreacted monomers, catalysts and oligomer residues, avoiding the blockage of membrane pore structure and interference with separation performance by impurities. At the same time, vacuum drying conditions help maintain the integrity of the membrane structure.

[0040] By constructing a confined reaction microenvironment to restrict reaction diffusion behavior, rapid burst bulk polymerization can be effectively suppressed, enabling two-dimensional continuous growth of the polymerization reaction. This significantly improves the density and continuity of the film layer and reduces the film defect rate. At the same time, the preparation method is simple, reproducible, and easy to scale up industrially.

[0041] Based on the application of rigid porous polymer membranes regulated by the restricted reaction microenvironment, the rigid porous polymer membranes prepared according to the above steps are applied to fields such as organic solvent nanofiltration (e.g., dye / solvent separation, pharmaceutical intermediate purification), crude oil separation (e.g., deasphalting, demetallization), gas separation (e.g., H2 / CH4, CO2 / N2 separation), pervaporation, and small molecule selective sieving, and are not limited to the above applications. They utilize their rigid pore structure and molecular sieving effect to achieve efficient retention and selective permeation of small molecules (e.g., molecular weight range of 200-1000 Da), while their excellent chemical stability allows them to withstand various organic solvents and harsh operating conditions such as high temperature and acid / alkali. Example 1

[0042] This embodiment provides a method for preparing rigid porous CMP membranes based on the Sonogashira-Hagihara coupling reaction, as detailed below: S1. Pretreatment of the supporting substrate: A polyacrylonitrile ultrafiltration membrane (pore size 20nm, thickness about 1mm, diameter 47mm) was selected as the supporting substrate. It was ultrasonically cleaned with deionized water, anhydrous ethanol and acetone for 30min each to remove surface contaminants. After cleaning, it was placed in a 60℃ forced-air drying oven for 12h for later use. S2. Prepare the first reaction precursor solution: Take 8 mL of triethylamine, 45 mol% (5.8 mg) of Pd (PPh3) and 5 mol% (1.9 mg) of CuI and add them to 20 mL of deionized water. Stir magnetically for 30 min under nitrogen protection at room temperature to fully dissolve the substances and obtain a clear and transparent solution A. S4. Prepare the second reaction precursor solution: Weigh 0.10 mmol (15.0 mg) of 1,3,5-triethynylbenzene and 0.15 mmol (35.4 mg) of 1,4-dibromobenzene and add them to a round-bottom flask. Add 20 mL of anhydrous toluene. Stir magnetically for 30 min under nitrogen protection at room temperature to obtain a homogeneous reaction solution B. S3. Constructing a confined reaction microenvironment: The polyacrylonitrile ultrafiltration membrane is spread on the surface of solution A. Triethylamine, Pd(PPh3)4 and CuI in solution A will diffuse to the surface of the polyacrylonitrile ultrafiltration membrane along with the aqueous solution. After standing at room temperature for 30 minutes, a stable confined liquid membrane layer is formed. S5. Confined polymerization reaction: The above solution B is rapidly added dropwise to the surface of the confined liquid film layer; the sample is placed in a high-pressure reactor lined with polytetrafluoroethylene, nitrogen is purged for 10 min to remove air, and the reaction is carried out at a constant temperature of 70℃ for 12 h under nitrogen protection. S6. Post-treatment: After the reaction is completed, the sample is naturally cooled to room temperature, taken out, and washed three times each with tetrahydrofuran (THF), anhydrous ethanol and acetone for 10 min each time to remove unreacted monomers and catalyst residues; then dried in a vacuum drying oven at 60℃ for 12 h to obtain CMP membrane.

[0043] The CMP film thickness obtained by SEM testing is approximately 10 nm. The film layer is uniform and continuous, with no obvious pinhole defects. Example 2

[0044] The same method as in Example 1 was used, except that a 100μm doctor blade was used to construct the confined liquid film layer, resulting in a confined thickness of approximately 50μm. The CMP film thickness obtained was approximately 480nm after testing. Example 3

[0045] The same method as in Example 1 was used, except that the polymerization reaction temperature was adjusted to 80°C and the reaction time was adjusted to 8 hours, resulting in a film thickness of approximately 350 nm, with a complete and continuous film layer. Example 4

[0046] In this embodiment, a PAF membrane was prepared by Suzuki-Miyaura coupling: 0.10 mmol (31.5 mg) of 1,3,5-tribromobenzene and 0.15 mmol (36.3 mg) of biphenyl diboronic acid were weighed and added to 20 mL of DMF, and 45 mol% of Pd(PPh3) was added as a catalyst; a 40 μm thick confined gel layer was constructed using polyvinyl alcohol gel, and the reaction was carried out at 80 °C under a nitrogen atmosphere for 10 h; after washing with THF and ethanol, the membrane was dried under vacuum to obtain the PAF membrane. Example 5

[0047] In this embodiment, a porous crosslinked membrane was prepared by Yamamoto coupling: 0.10 mmol of tetrabromobiphenyl was weighed and added to 20 mL of LDMF, and 10 mol% of Ni(COD)2 was added as a catalyst; the membrane was reacted at 70 °C for 12 h in a 30 μm confined liquid membrane layer; after washing and drying, a crosslinked membrane with a thickness of about 390 nm was obtained.

[0048] Comparative Example 1 Without setting up a restricted reaction microenvironment, the mixed reaction solution from Example 1 was directly placed in a flask and reacted at 60°C for 12 hours. The resulting product was a yellow granular precipitate that could not adhere to the substrate to form a continuous film.

[0049] Comparative Example 2 Using the same method as in Example 1, but with the confinement layer thickness reduced to 0.5 μm, it was found that local particle aggregation still occurred, the resulting film layer was discontinuous, and the substrate was locally exposed.

[0050] Comparative Example 3 Using the same method as in Example 1, but with the confinement layer thickness increased to 2000 μm, the reaction diffusion was severely hindered, the film formation rate decreased, and the film adhesion was significantly reduced.

[0051] Comparative Example 4 Using the same method as in Example 1, but with the reaction temperature increased to 140°C, the polymerization rate was too fast, the surface roughness of the resulting film increased, and obvious cracks appeared.

[0052] The membranes prepared in the examples and comparative examples were subjected to performance tests, and the test results are shown in the table below: Table 1

[0053] From Table 1, we can obtain: (1) The comparison between Example 1 and Comparative Example 1 shows that the present invention actively regulates reaction-diffusion coupling by constructing a confined reaction microenvironment, rather than simply relying on interface contact. In Comparative Example 1, no confined microenvironment was set up, and the reactants diffused rapidly and polymerized explosively in the open system, resulting in only particulate precipitates that could not form a film. In contrast, Example 1 effectively suppressed disordered diffusion through a confined liquid film layer and successfully obtained a continuous and complete film layer.

[0054] (2) Through comparison and verification between Example 1 and Comparative Examples 2, 3 and 4, it was found that: the present invention controls the local concentration gradient and reaction kinetics to achieve two-dimensional preferential growth. In Comparative Example 2, the confinement layer was too thin (0.5 μm), and the local concentration was still too high, resulting in agglomeration; in Comparative Example 3, the confinement layer was too thick (2000 μm), and the reaction diffusion was severely hindered, resulting in a decrease in film adhesion; in Comparative Example 4, the reaction temperature was too high (140℃), and the polymerization rate was out of control, resulting in film cracking; while Examples 1 to 5 all obtained continuous, dense, and low defect rate films within the preferred parameter range, proving that the present invention achieves two-dimensional preferential growth by precisely controlling the confinement scale and reaction conditions.

[0055] (3) The successful implementation of Examples 1 (Sonogashira-Hagihara), 4 (Suzuki-Miyaura), and 5 (Yamamoto) verifies that the present invention is applicable to a variety of coupling reaction systems and has platform versatility. In particular, continuous film formation can be achieved in a confined reaction microenvironment through different coupling reaction types, different monomer combinations, and different catalyst systems, indicating that the method of the present invention is not limited to a single chemical reaction system and has wide applicability.

[0056] Comprehensive analysis reveals that traditional membrane preparation technologies (mainly including interfacial polymerization membranes, template-assisted CMP membrane formation, and in-situ deposition CMP membrane technology) do not disclose the use of confined reaction microenvironment systems to regulate reaction diffusion behavior and induce continuous two-dimensional growth of rigid porous polymers. In contrast, this invention constructs a confined reaction microenvironment (liquid film layer, gel layer, template pore layer, capillary pore layer, or interfacial wetting layer) with adjustable thickness (1 nm to 1000 μm) to actively control the reactant diffusion path and local concentration gradient, suppressing rapid burst bulk polymerization and enabling preferential growth of the polymerization reaction along the two-dimensional direction. This significantly improves membrane density and continuity, reduces defect rates, and is simple, reproducible, and applicable to various coupling reaction systems. It solves the problems of difficult thickness control, poor continuity, high defect rates, and insufficient reproducibility in existing rigid porous polymer membranes, and can be widely applied in industrial separation applications.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A rigid porous polymer membrane based on the controlled microenvironment of a confined reaction, characterized in that, The rigid porous polymer membrane includes a porous substrate and a rigid porous polymer separation layer loaded on the surface of the substrate; The substrate is selected from any one of polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, polyethersulfone, polyacrylonitrile, alumina ceramic membrane or zirconium oxide; The rigid porous polymer layer is prepared by in-situ polymerization in a confined reaction microenvironment. The confined reaction microenvironment is constructed by pre-wetting or coating the surface of the porous substrate with a physical confinement layer of 1 μm-1000 μm thickness. The confinement layer is composed of at least one selected from liquid film layer, gel layer or polymer coating, and is used to regulate the diffusion rate of reaction precursors during polymerization.

2. The rigid porous polymer membrane based on the controlled microenvironment of a confined reaction environment according to claim 1, characterized in that: The rigid porous polymer separation layer is selected from at least one of conjugated microporous polymers, porous aromatic skeleton polymers, covalent organic framework polymers, COF-derived networks, and intrinsically microporous polymer crosslinking networks.

3. The rigid porous polymer membrane based on the controlled microenvironment of a confined reaction environment according to claim 1, characterized in that: The confined reaction microenvironment is a spatially confined region that can limit the diffusion of reaction precursors and regulate the local concentration gradient.

4. A rigid porous polymer membrane as described in any one of claims 1-3, characterized in that, The preparation steps include the following: S1. Pretreatment: The support substrate is ultrasonically cleaned sequentially with deionized water, anhydrous ethanol and acetone, and then dried to obtain a clean substrate. S2. Constructing a confined reaction microenvironment: The pretreated substrate is spread on the first reaction precursor solution containing the catalyst and base, and allowed to stand to form a confined liquid film layer. S3. Preparation of reaction precursor solution: Prepare a second reaction precursor solution containing rigid organic monomers; S4, confined polymerization reaction: The second reaction precursor solution prepared in S3 is introduced into the confined reaction microenvironment constructed in S2 to carry out the confined polymerization reaction; S5. Post-treatment: The products after the confined polymerization reaction are washed and dried sequentially with organic solvents to obtain a rigid porous polymer membrane.

5. The rigid porous polymer membrane based on the controlled microenvironment of a confined reaction as described in claim 4, characterized in that: The pretreatment conditions in S1 are as follows: ultrasonic cleaning time is 10-60 min for each; drying treatment is to place in a forced-air drying oven at 40-80℃ for 6-24 h.

6. The rigid porous polymer membrane based on the controlled microenvironment of a confined reaction as described in claim 4, characterized in that: The confined reaction microenvironment in S2 includes at least one of the following: liquid film layer, gel layer, template pore layer, capillary pore layer, and interface wetting layer. The construction conditions for the confined reaction microenvironment are as follows: (1) When a liquid film layer is used, a confined liquid film layer is formed by spreading the substrate on the surface of the first reaction precursor solution and letting it stand at room temperature for 15 to 60 minutes; or a liquid film layer of a limited thickness is constructed by using a scraper. (2) When using a gel layer, a confined gel layer with a thickness of 10 to 100 μm is constructed using polyvinyl alcohol or other hydrogels; The thickness of the finally prepared confined reaction microenvironment ranged from 1 nm to 1000 μm. The first reaction precursor solution is prepared according to the selected polymerization reaction type and is selected from one of the following combinations: (1) For the Sonogashira-Hagihara coupling reaction: Triethylamine, Pd(PPh3)4 and CuI were added to deionized water and magnetically stirred for 15-60 min under nitrogen protection at room temperature to obtain a clear solution; (2) For the Suzuki-Miyaura coupling reaction: Pd(PPh3)4 and alkali are dissolved in DMF or toluene; (3) For the Yamamoto coupling reaction: Ni(COD)2 is dissolved in DMF.

7. The rigid porous polymer membrane based on the controlled microenvironment of a confined reaction as described in claim 4, characterized in that: In step S3, the reaction precursor solution is prepared by dissolving a rigid organic monomer in an anhydrous organic solvent and magnetically stirring for 15–60 min under nitrogen protection at room temperature to obtain a second reaction precursor solution. The rigid organic monomer is selected from at least two aromatic or heterocyclic monomers having a rigid core and at least two terminal reactive groups. The rigid core is selected from one or more of substituted or unsubstituted benzene, biphenyl, terphenyl, naphthalene, anthracene, pyrene, triazine, spirodifluorene, or porphyrin structures. The terminal reactive groups are selected from one or more of halogen groups, terminal alkynyl groups, borate groups, or borate ester groups. The organic solvent is selected from anhydrous toluene, DMF, THF, NMP, DMSO, or 1,4-dioxane.

8. The rigid porous polymer membrane based on the controlled microenvironment of a confined reaction as described in claim 7, characterized in that, The reaction conditions in S4 are as follows: the polymerization reaction includes at least one of Sonogashira-Hagihara coupling, Suzuki-Miyaura coupling, Yamamoto coupling, Buchwald-Hartwig coupling, and Scholl oxidative coupling; the thickness of the confined reaction microenvironment is 1 nm to 1000 μm; the polymerization reaction temperature is 20 to 150 °C; the polymerization reaction time is 0.5 to 24 h; and the entire reaction is carried out under nitrogen protection.

9. The rigid porous polymer membrane based on the controlled microenvironment of a confined reaction as described in claim 7, characterized in that: The combination of the rigid organic monomers is selected from any of the following: (1) Coupling type: selected from at least two of 1,3,5-triethynylbenzene, 1,4-diethynylbenzene, 1,4-dibromobenzene, 1,3,5-tribromobenzene, 4,4'-biphenyl diboronic acid, 4,4'-dibromobiphenyl, tetra(4-bromophenyl)methane, and 2,4,6-tris(4-bromophenyl)-1,3,5-triazine; (2) Oxidative coupling type: Aromatic monomers containing aryl hydrogen.

10. The rigid porous polymer membrane based on the controlled microenvironment of a confined reaction as described in claim 4, characterized in that: The organic solvent washing is carried out sequentially using one or more of tetrahydrofuran, anhydrous ethanol and acetone, each washing is performed 1 to 3 times, each time for 5 to 30 minutes; the drying conditions are: vacuum drying at 40 to 120°C for 6 to 24 hours; the resulting rigid porous polymer film has a thickness of 10 nm to 100 μm, and the film layer is uniform and continuous without obvious pinhole defects.

11. The application of rigid porous polymer membranes based on the control of confined reaction microenvironment, characterized in that, The rigid porous polymer membrane prepared according to claim 4 is applied in the fields of organic solvent nanofiltration, crude oil separation, gas separation, pervaporation and selective sieving of small molecules.

Images