An ordered nanochannel polymer separation membrane based on a bicontinuous solvolytic liquid crystal and a preparation method and application thereof

Abstract

The application discloses an ordered nanochannel polymer separation membrane based on a bicontinuous solvothermal liquid crystal and a preparation method and application thereof. The method takes a gemini type amphiphilic molecule containing a polymerizable group as a precursor, and a chiral tartaric acid counterion is introduced to control self-assembly to form a bicontinuous solvothermal liquid crystal intermediate phase (double gyroid). After adding a photoinitiator to the system, in-situ polymerization / crosslinking solidification is achieved by adopting ultraviolet irradiation, and a polymer membrane which maintains the ordered structure of the solvothermal liquid crystal, has three-dimensional connected ordered nanochannels and is mechanically stable is obtained. The separation membrane can be used for membrane separation and purification of a racemic mixture, shows enantiomer selective permeation for 1-phenyl ethanol, ibuprofen and other racemic systems, and is suitable for enantiomer separation of chiral drugs and fine chemicals.

Description

Technical Field

[0001] This invention relates to the field of ordered separation membranes, specifically to a method for preparing polymer membranes with ordered nanochannels via a liquid crystal mesophase and the application of ordered nanochannel polymer membranes in enantiomeric separation. Background Technology

[0002] In the 21st century, polymer membrane separation has become a commonly used separation and purification method in fields such as water treatment, food, pharmaceuticals, and semiconductor manufacturing. Compared with separation technologies such as distillation, extraction, adsorption, and chromatography, membrane separation technology has advantages such as low energy consumption, short process, and ease of continuous integration, giving it significant advantages in industrial separation applications.

[0003] However, the application of existing polymer membranes in the fine separation of high value-added products (especially nanoscale sieving and high-selectivity purification) still has significant limitations. For example, the pore structure formed by conventional membrane fabrication processes is mostly statistically distributed with dispersed pore sizes, resulting in insufficiently narrow separation windows and limited selectivity. In addition, in high-throughput applications, selectivity often decreases, and in complex systems, problems such as pore blockage, obstructed mass transfer pathways, and performance degradation can easily occur.

[0004] To obtain more controllable channel structures, self-assembled liquid crystals have attracted attention due to their ability to spontaneously form nanoscale ordered structures. Partial liquid crystal mesophases can form ordered channels with characteristic sizes of 1-2 nm, which, in principle, is beneficial for constructing separation films with more concentrated pore sizes and more uniform structures. Among them, ordered bicontinuous structures possess three-dimensional interconnected channels, effectively reducing mass transfer problems caused by dead-end channels. They can provide through-channel transport without relying on external field orientation, and are theoretically more suitable for high-throughput separation scenarios.

[0005] However, the preparation of ordered separation membranes using liquid crystal mesophases still faces some challenges in practical applications. For example, the structure formation is sensitive to formulation, solvent system, and processing conditions, resulting in a narrow preparation window; the film formation and curing processes are complex, and the mechanical stability and long-term operational stability are poor without a supporting substrate. Therefore, there is an urgent need for a process-controllable, repeatable, and easily scalable method for preparing ordered nanochannel polymer membranes to meet practical application requirements while maintaining structural order and self-supporting stability, and to further expand its application in fine separation scenarios such as enantiomeric separation. Summary of the Invention

[0006] In view of the problems existing in the prior art, the present invention provides a method for preparing ordered nanochannel polymer membranes through liquid crystal mesophase and its application in enantiomer separation. The present invention can construct enantiomer separation membranes with ordered bicontinuous structures through simple and easily controllable membrane preparation technology, which has good application prospects in the separation of racemic mixtures of chiral drugs.

[0007] To achieve the above objectives, the present invention provides a method for preparing an ordered nanochannel polymer separation membrane based on a dual-continuous lyotropic liquid crystal, comprising the following steps: Step 1) Synthesize polymerizable amphiphilic molecules: Step 1-1 Synthesis of a polymerizable amphiphilic precursor – 11-bromoundecyl methacrylate: 11-bromo-1-undecyl alcohol, triethylamine and 4-methoxyphenol were dissolved in anhydrous dichloromethane, mixed thoroughly, and then cooled by stirring in an ice bath at 0 °C for 30 min. The monomer with polymerizable groups was dissolved in anhydrous dichloromethane and slowly added dropwise to the above mixture under ice bath conditions. After the addition was complete, the temperature of the reaction system was raised to 25 °C and the reaction was stirred for 12 h. After the reaction was completed, the reaction solution was washed with saturated sodium bicarbonate aqueous solution to remove impurities. After multiple extractions and separations with anhydrous dichloromethane, the dichloromethane organic phase containing the product was collected. Excess dichloromethane was removed by vacuum distillation to obtain the crude product. The crude product was purified by silica gel column chromatography to obtain the target product, 11-bromoundecyl methacrylate. Steps 1-2: Synthesis of the polymerizable amphiphilic precursor - N,N′-bis[11-(methacryloyloxy)undecyl]-N,N,N′,N′-tetramethyl-1,6-hexammonium dibromide G6: 11-Bromoundecyl methacrylate, N,N,N′,N′-tetramethyl-1,6-hexanediamine, and 4-methoxyphenol were dissolved in a toluene / acetonitrile mixture. The reaction solution was refluxed at 80 °C and stirred for 24 h. After the reaction was completed, the solvent was removed under reduced pressure, and ethyl acetate was added to the residue to induce the precipitation of a white precipitate, yielding a crude product. The crude product was collected by vacuum filtration and washed three times with ethyl acetate and n-hexane, respectively. The obtained solid was dried under vacuum at room temperature for 24 h to obtain a white powder product, named G6. Steps 1-3: Synthesis of polymerizable amphiphilic molecule G6-L via ion exchange: L(+)-tartaric acid and silver carbonate were added to methanol and ultrasonically dispersed. The mixture was then stirred at room temperature for 6 hours under light-protected conditions to prepare silver tartrate. Subsequently, G6 and 4-methoxyphenol were added to the above system and stirred at 40 °C for 1 hour. The mixture was then transferred to room temperature and stirred for another 12 hours to complete the ion exchange. The counter ion of the amphiphilic molecule was converted from bromide ion to tartaric acid ion. The silver bromide insolubles generated after the reaction were removed by filtration to obtain a clear and transparent filtrate. The filtrate was then subjected to vacuum distillation to remove excess methanol, resulting in a clear and transparent viscous liquid. A large amount of anhydrous diethyl ether was added to the clear liquid to induce precipitation. The precipitated solid was collected by centrifugation, washed with anhydrous diethyl ether, and then vacuum dried at 25 °C for 12 h to obtain a white waxy product named G6-L. Step 2) Preparation of lyotropic liquid crystals with an ordered bicontinuous structure: Lyotropic liquid crystals were prepared by mixing the amphiphilic molecules synthesized in step 1) with deionized water in a fixed ratio. In a 2 ml centrifuge tube, the amphiphilic molecules and water were mixed in a mass ratio of 88:12. After stirring evenly, the mixture was heated to a clear state and then centrifuged in a high-speed centrifuge for 5 min. This process was repeated three times to ensure that the amphiphilic molecules and water were mixed evenly, resulting in a uniform and transparent colloidal aggregate. This colloidal aggregate is the lyotropic liquid crystal with an ordered bicontinuous structure. Step 3) Preparation of polymer film via lyotropic liquid crystal: A polymer film was prepared by curing the lyotropic liquid crystal obtained in step 2) using ultraviolet curing; a photoinitiator was added to the prepared lyotropic liquid crystal; the mixing steps were repeated to finally obtain a uniform gel-like aggregate containing the photoinitiator; The homogeneous lyotropic liquid crystal was transferred between two hydrophobic transparent glass plates that had undergone fluorosilane treatment, and the distance between the two substrates was controlled by a spacer to control the film thickness. The assembled system was then subjected to thermal annealing to ensure that the intermediate phase was fully balanced. After the system was stabilized and balanced, the lyotropic liquid crystal was cured at room temperature using an ultraviolet light source to obtain a mechanically stable polymer film. Step 4) Membrane pretreatment for enantiomeric separation: Step 3) involves cutting a polymer membrane using a mold of a fixed size to prepare a separation membrane with a standard size. The membrane sample of the fixed size is then subjected to dehydration treatment to remove water from the channels inside the membrane, and then soaked in n-hexane for later use.

[0008] Preferably, the monomer with polymerizable groups in step 1) of the present invention is methacryloyl chloride.

[0009] Preferably, the mixed reaction solvent in steps 1-2 of the present invention is toluene:acetonitrile = 1:1.

[0010] Preferably, tartaric acid is used as a reactant in step 1) of the present invention for ion exchange.

[0011] Preferably, the high-speed centrifuge speed in step 2) of the present invention is 15000 rpm / min.

[0012] Preferably, in step 3) of the present invention, the photoinitiator is 2-hydroxy-2-methylpropionyl phenyl ketone, with a content of 1 wt%.

[0013] Preferably, the ultraviolet curing conditions in step 3) of the present invention are: light source 365nm, curing temperature 25℃, and luminous flux 800 mW / cm². 2 The curing time is 100 seconds.

[0014] Preferably, in step 4) of the present invention, the membrane is subjected to dehydration treatment in the early stage, and is soaked in ethanol for 12 hours and then vacuum dried.

[0015] The present invention also provides an ordered nanochannel polymer separation membrane.

[0016] Based on the precisely tunable self-assembly structure of ordered bicontinuous lyotropic liquid crystals and their inherent nanoscale characteristic channels, this invention provides a method for preparing ordered nanochannel polymer separation membranes. This method uses bicontinuous lyotropic liquid crystals as the structural basis, and achieves in-situ cross-linking and curing under ultraviolet light by introducing methacrylate groups into the system. While preserving the ordered bicontinuous structure with high fidelity, the lyotropic liquid crystal is transformed into a polymer membrane with three-dimensionally interconnected ordered nanochannels. The polymer membrane preparation process involves few steps, mild conditions, and the membrane thickness can be controlled by spacers. It features simple operation, good repeatability, and controllable structure, making it suitable for scale-up preparation.

[0017] The prepared separation membrane can be used for the separation of racemic mixtures, and is particularly suitable for the enantioselective separation of racemic chiral drugs. In a representative system, it exhibits significant enantioselectivity for both R / S-1-phenylethanol and R / S-ibuprofen racemic mixtures, with enantioselectivity (ee) of the separated products reaching 100%.

[0018] Compared with existing polymer separation membranes, this invention, through "precise self-assembly structure + UV curing preservation", helps to alleviate problems such as disordered pore structure, wide pore size distribution and numerous defects in traditional membrane fabrication processes, thereby improving membrane structure consistency and separation stability, and has good application prospects in the field of fine separation of chiral drugs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the ordered bicontinuous gyroid structure inside the ordered nanochannel separation membrane based on bicontinuous lyotropic liquid crystal prepared in this invention.

[0020] Figure 2 These are synchrotron radiation small-angle X-ray scattering data of lyotropic liquid crystals in Embodiments 1, 5, and 6 of the present invention.

[0021] Figure 3 Photograph of the ordered nanochannel separation membrane based on dual continuous lyotropic liquid crystal prepared according to the present invention.

[0022] Figure 4Infrared spectra of ordered nanochannel separation membranes based on dual continuous lyotropic liquid crystals prepared for the invention.

[0023] Figure 5 Synchrotron radiation small-angle X-ray diffraction data of the ordered nanochannel separation membrane based on dual continuous lyotropic liquid crystal prepared for the invention.

[0024] Figure 6 This is the HPLC spectrum of the permeate in Example 1 of the present invention. Detailed Implementation

[0025] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings: Example 1: A method for preparing an ordered nanochannel polymer separation membrane based on dual continuous lyotropic liquid crystals and its enantiomeric separation application process, comprising the following steps: Step 1) Synthesis of polymerizable amphiphilic molecules Step 1-1 Synthesis of a polymerizable amphiphilic precursor – 11-bromoundecyl methacrylate 11-Bromo-1-undecanol (10 g, 39.8 mmol), triethylamine (6.46 mL, 49.8 mmol), and 4-methoxyphenol (polymerization inhibitor, 0.1 g) were dissolved in anhydrous dichloromethane (80 mL), mixed thoroughly, and then cooled under 0 °C ice bath conditions for 30 min with stirring.

[0026] Methacryloyl chloride (5.78 mL, 49.8 mmol) was dissolved in anhydrous dichloromethane (20 mL) and slowly added dropwise to the mixture under ice bath conditions. After the addition was complete, the reaction temperature was raised to 25 °C and the reaction was stirred for 12 h. After the reaction was completed, the reaction solution was washed with saturated sodium bicarbonate aqueous solution to remove impurities such as the generated triethylamine salt. After multiple extractions with anhydrous dichloromethane, the dichloromethane organic phase containing the product was collected, and excess dichloromethane was removed by vacuum distillation to obtain the crude product. The crude product was purified by silica gel column chromatography (eluent: n-hexane / ethyl acetate = 40:1, V / V) to obtain the target product, 11-bromoundecyl methacrylate.

[0027] Steps 1-2: Synthesis of the polymerizable amphiphilic precursor - N,N′-bis[11-(methacryloyloxy)undecyl]-N,N,N′,N′-tetramethyl-1,6-hexammonium dibromide (G6) 11-bromoundecyl methacrylate (5.0 g, 15.7 mmol), N,N,N′,N′-tetramethyl-1,6-hexanediamine (1.5 mL, 7.0 mmol), and 4-methoxyphenol (0.1 g, polymerization inhibitor) were dissolved in a mixed solvent of toluene (30 mL) and acetonitrile (30 mL). The reaction solution was stirred under reflux at 80 °C for 24 h. After the reaction was completed, the solvent was removed under reduced pressure, and ethyl acetate was added to the residue to induce the precipitation of a white precipitate, yielding a crude product. The crude product was collected by vacuum filtration and washed three times successively with ethyl acetate and n-hexane. The obtained solid was dried under vacuum at room temperature (25 °C) for 24 h to obtain a white powder product, named G6.

[0028] Steps 1-3 involve the synthesis of polymerizable amphiphilic molecules (G6-L) via ion exchange. L(+)-tartaric acid (L-TA, 0.277 g, 1.85 mmol) and silver carbonate (Ag₂CO₃, 0.51 g, 1.85 mmol) were added to methanol (80 mL), ultrasonically dispersed, and stirred at room temperature for 6 h in the dark to prepare silver tartrate. Then, G6 (1.50 g, 1.85 mmol) and 4-methoxyphenol (0.10 g, polymerization inhibitor) were added to the above system, and the mixture was stirred at 40 °C for 1 h, then transferred to room temperature and stirred for another 12 h to complete the ion exchange. The counter ion of the amphiphilic molecule was converted from bromide ions to tartaric acid ions.

[0029] The silver bromide insolubles generated after the reaction were removed by filtration, yielding a clear and transparent filtrate. Excess methanol in the filtrate was removed by vacuum distillation, resulting in a clear, transparent, viscous liquid. A large amount of anhydrous diethyl ether was added to the resulting clear liquid to induce precipitation. The precipitated solid was collected by centrifugation, washed with anhydrous diethyl ether, and then vacuum dried at 25 °C for 12 h to obtain a white, waxy product named G6-L.

[0030] Step 2) Preparation of lyotropic liquid crystals with an ordered bicontinuous structure Lyotropic liquid crystals were prepared by mixing the amphiphilic molecules synthesized in step 1) with deionized water in a fixed ratio. In 2 ml centrifuge tubes, the amphiphilic molecules and water were mixed at a mass ratio of 88:12 (amphiphilic molecules:deionized water). After stirring thoroughly, the mixture was heated to a clear state and then centrifuged for 5 min in a high-speed centrifuge. This process was repeated three times to ensure uniform mixing of the amphiphilic molecules and water, resulting in a homogeneous and transparent colloidal aggregate. The assembly structure of the colloidal aggregate was determined using synchrotron small-angle X-ray scattering (SAXS) technique. Figure 2As shown, when the amphiphilic molecular mass percentages are 90%, 88%, and 86%, SAXS data reveal as many as eight diffraction peaks with scattering vector q ratios of √6:√8:√14:√16:√20:√22:√24:√26. SAXS data confirm that this colloidal aggregate is a lyotropic liquid crystal with an ordered bicontinuous gyroid structure.

[0031] Step 3) Preparation of polymer film via lyotropic liquid crystal Polymer films were prepared by curing the lyotropic liquid crystal obtained in step 2) using ultraviolet curing. 1 wt% of the photoinitiator 2-hydroxy-2-methylpropiophenone was added to the prepared lyotropic liquid crystal. The mixing steps were repeated to finally obtain a homogeneous gel-like aggregate containing the photoinitiator.

[0032] The homogeneously mixed lyotropic liquid crystal was transferred between two hydrophobic transparent glass substrates treated with fluorosilane, and the film thickness was controlled by adjusting the distance between the two substrates using a spacer. The assembled system was then thermally annealed to ensure adequate equilibrium of the intermediate phase. After the system reached stable equilibrium, the lyotropic liquid crystal was cured at room temperature using a 365 nm ultraviolet light source with an ultraviolet flux of 800 mW / cm². 2 A curing time of 100 seconds yields a mechanically stable polymer film, such as... Figure 3 As shown, the polymer film has a uniform and transparent appearance. The effect of the polymerization process on the preservation of the lyotropic liquid crystal assembly structure can be determined by SAXS characterization. Figure 5 As shown, the SAXS spectrum of the polymer film sample also exhibits eight diffraction peaks, with a scattering vector q ratio of √6:√8:√14:√16:√20:√22:√24:√26. This indicates that the lyotropic liquid crystal structure was preserved with high fidelity.

[0033] Step 4) Membrane pretreatment for enantiomeric separation Step 3) involved cutting polymer membranes using a fixed-size mold (diameter: 22 mm) to prepare separation membranes of standard dimensions. The fixed-size membrane samples were immersed in anhydrous ethanol for 12 hours, then vacuum-dried to remove water from the membrane channels, and subsequently immersed in n-hexane for later use. The chemical stability during the process was determined by Fourier transform infrared spectroscopy, such as... Figure 4 As shown, the main absorption peaks of the Fourier transform infrared spectrum of the polymer membrane did not show significant differences during the dehydration and hexane soaking process, indicating that the internal chemical structure of the polymer membrane was not damaged during the treatment.

[0034] Step 5) Enantiomer Separation Application Process Enantiomer separation performance was evaluated using a U-shaped diffusion cell apparatus, with the feed chamber and permeation chamber arranged side-by-side, separated at the center by the polymer separation membrane (100 μm thick) prepared in step 4). The membrane was fixed between two sealing rings, with an effective permeation diameter of 16 mm. 200 mL of a hexane solution containing the enantiomers of S-1-phenylethanol and R-1-phenylethanol at a concentration ratio of 1:1 (0.05 M for each enantiomer) was added to the feed chamber, and an equal volume of hexane was added to the permeation chamber. During permeation, both chambers were continuously stirred with a magnetic stirrer to maintain system homogeneity. A 1 mL sample was taken from the permeation chamber every 2 h and analyzed by high-performance liquid chromatography (HPLC).

[0035] HPLC results showed that the polymer membrane prepared using G6-L exhibited significant enantioselectivity in the racemic 1-phenylethanol system. Figure 6 As shown, after 2 h of diffusion, only the chromatographic peak of S-1-phenylethanol was detected in the HPLC results of the permeate-side solution sample, and no corresponding signal of R-1-phenylethanol was observed. This result indicates that the membrane exhibits significant selective transport behavior for both enantiomers.

[0036] Separation mechanisms such as Figure 1 As shown, during the passage of racemic 1-phenylethanol molecules through a polymer membrane with a gyroid structure, the 1-phenylethanol molecules interact with chiral counterions in the gyroid channels. The R-1-phenylethanol molecule interacts more strongly with the chiral counterions, resulting in slow diffusion. This preferentially allows the S-1-phenylethanol molecule to pass through, thereby achieving efficient chiral separation of racemic 1-phenylethanol mixtures.

[0037] Examples 2, 3, and 4: The difference between each example and Example 1 is that in step 1, (1) the precursor for synthesizing the polymerizable amphiphilic molecule, 11-bromoundecyl methacrylate, was extracted with aqueous solution to remove impurities such as triethylamine salt. (2) The precursor for synthesizing the polymerizable amphiphilic molecule, N,N′-bis[11-(methacryloyloxy)undecyl]-N,N,N′,N′-tetramethyl-1,6-hexammonium dibromide (G6), was prepared using a mixed solvent of acetonitrile (19 ml) and water (1 ml) as the reaction solvent. (3) The precursor for synthesizing the polymerizable amphiphilic molecule, N,N′-bis[11-(methacryloyloxy)undecyl]-N,N,N′,N′-tetramethyl-1,6-hexammonium dibromide (G6), was washed with ethyl acetate and tetrahydrofuran. Compared with Example 1, the purity of the prepared polymerizable amphiphilic molecule was consistent.

[0038] Examples 5 and 6: The difference between these examples and Example 1 lies in the mass ratio of amphiphilic molecules to deionized water in step 2, which is 90:10 and 86:14, respectively. Specific differences in the lyotropic liquid crystal structure were characterized using synchrotron radiation small-angle X-ray diffraction (SAXS), such as... Figure 2 .

[0039] Examples 7 and 8: The difference between these examples and Example 1 lies in the mass ratio of amphiphilic molecules to deionized water in step 2, which is 95:5 and 78:22, respectively. By adjusting the ratio of amphiphilic molecules to deionized water, lyotropic liquid crystals with layered and hexagonal columnar structures can be obtained, respectively.

[0040] Examples 9, 10, 11, 12, 13, and 14: The difference between these examples and Example 1 is that the photoinitiator content in step 3 is 2 wt%. The ultraviolet light flux is 200 mW / cm². 2 400 mW / cm 2 600 mW / cm 2 The UV curing times were 50s, 150s, and 200s. The polymer film prepared under the UV curing conditions used in this example showed broader diffraction peaks in the SAXS data compared to that in Example 1.

[0041] Example 15: The difference between this example and Example 1 lies in step 5, where a racemic ibuprofen mixture is used as the feed solution for the enantiomeric separation process. HPLC results show that after 2 hours of diffusion, only the chromatographic peak of S-1-ibuprofen was detected on the permeate side. This indicates that the membrane exhibits significant selective transport behavior for both enantiomers, preferentially allowing S-ibuprofen molecules to pass through, thereby achieving efficient chiral separation of the racemic ibuprofen mixture.

[0042] As can be seen from the above embodiments, the preparation method provided by the present invention can effectively solidify and shape-preserve the ordered nanoscale structure of the mesophase using an ordered bicontinuous lyotropic liquid crystal mesophase as a structural template through an in-situ polymerization and crosslinking process initiated by ultraviolet light, transforming it into a polymer separation membrane with three-dimensional interconnected ordered nanochannels. This method features simple process steps, controllable conditions, and good mechanical stability of the resulting membrane material. Simultaneously, the curing and crosslinking film formation process is short and fast, which is beneficial for improving preparation efficiency and batch consistency. It has good engineering operability and scale-up potential.

[0043] Furthermore, the separation results in the examples further demonstrate that the ordered nanochannel polymer separation membrane can be used for membrane separation and purification of racemic mixtures, especially suitable for the enantioselective separation of chiral small molecules (racemic mixtures). Under preferred conditions, high enantioselectivity can be obtained for representative racemic systems such as R / S-1-phenylethanol and R / S-ibuprofen, and the enantioselectivity (ee) of the separated products can reach a high level, thus possessing application value in chiral drug resolution, fine chemical purification, and related continuous separation processes.

[0044] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing an ordered nanochannel polymer separation membrane based on a dual-continuous lyotropic liquid crystal, comprising the following steps: Step 1) Synthesize polymerizable amphiphilic molecules: Step 1-1 Synthesis of a polymerizable amphiphilic precursor – 11-bromoundecyl methacrylate: 11-bromo-1-undecyl alcohol, triethylamine and 4-methoxyphenol were dissolved in anhydrous dichloromethane, mixed thoroughly, and then cooled by stirring in an ice bath at 0°C for 30 min. The monomer with polymerizable groups was dissolved in anhydrous dichloromethane and slowly added dropwise to the above mixture under ice bath conditions. After the addition was complete, the temperature of the reaction system was raised to 25 °C and the reaction was stirred for 12 h. After the reaction was completed, the reaction solution was washed with saturated sodium bicarbonate aqueous solution to remove impurities. After multiple extractions and separations with anhydrous dichloromethane, the dichloromethane organic phase containing the product was collected. Excess dichloromethane was removed by vacuum distillation to obtain the crude product. The crude product was purified by silica gel column chromatography to obtain the target product, 11-bromoundecyl methacrylate. Steps 1-2: Synthesis of the polymerizable amphiphilic precursor - N,N′-bis[11-(methacryloyloxy)undecyl]-N,N,N′,N′-tetramethyl-1,6-hexammonium dibromide G6: 11-Bromoundecyl methacrylate, N,N,N′,N′-tetramethyl-1,6-hexanediamine, and 4-methoxyphenol were dissolved in a toluene / acetonitrile mixture. The reaction solution was refluxed at 80 °C and stirred for 24 h. After the reaction was completed, the solvent was removed under reduced pressure, and ethyl acetate was added to the residue to induce the precipitation of a white precipitate, yielding a crude product. The crude product was collected by vacuum filtration and washed three times with ethyl acetate and n-hexane, respectively. The obtained solid was dried under vacuum at room temperature for 24 h to obtain a white powder product, named G6. Steps 1-3: Synthesis of polymerizable amphiphilic molecule G6-L via ion exchange: L(+)-tartaric acid and silver carbonate were added to methanol and ultrasonically dispersed. The mixture was then stirred at room temperature for 6 h under light-protected conditions to prepare silver tartrate. Subsequently, G6 and 4-methoxyphenol were added to the above system and stirred at 40 °C for 1 h. The mixture was then transferred to room temperature and stirred for another 12 h to complete the ion exchange. The counter ion of the amphiphilic molecule was converted from bromide ion to tartaric acid ion. The silver bromide insolubles generated after the reaction were removed by filtration to obtain a clear and transparent filtrate. The filtrate was then subjected to vacuum distillation to remove excess methanol, resulting in a clear and transparent viscous liquid. A large amount of anhydrous diethyl ether was added to the clear liquid to induce precipitation. The precipitated solid was collected by centrifugation, washed with anhydrous diethyl ether, and then vacuum dried at 25 °C for 12 h to obtain a white waxy product named G6-L. Step 2) Preparation of lyotropic liquid crystals with an ordered bicontinuous structure: Lyotropic liquid crystals were prepared by mixing the amphiphilic molecules synthesized in step 1) with deionized water in a fixed ratio. In a 2 ml centrifuge tube, the amphiphilic molecules and water were mixed in a mass ratio of 88:

12. After stirring evenly, the mixture was heated to a clear state and then centrifuged in a high-speed centrifuge for 5 min. This process was repeated three times to ensure that the amphiphilic molecules and water were mixed evenly, resulting in a uniform and transparent colloidal aggregate. This colloidal aggregate is the lyotropic liquid crystal with an ordered bicontinuous structure. Step 3) Preparation of polymer film via lyotropic liquid crystal: A polymer film was prepared by curing the lyotropic liquid crystal obtained in step 2) using ultraviolet curing; a photoinitiator was added to the prepared lyotropic liquid crystal; the mixing steps were repeated to finally obtain a uniform gel-like aggregate containing the photoinitiator; The homogeneous lyotropic liquid crystal was transferred between two hydrophobic transparent glass plates that had undergone fluorosilane treatment, and the distance between the two substrates was controlled by a spacer to control the film thickness. The assembled system was then subjected to thermal annealing to ensure that the intermediate phase was fully balanced. After the system was stabilized and balanced, the lyotropic liquid crystal was cured at room temperature using an ultraviolet light source to obtain a mechanically stable polymer film. Step 4) Membrane pretreatment for enantiomeric separation: Step 3) involves cutting a polymer membrane using a mold of a fixed size to prepare a separation membrane with a standard size. The membrane sample of the fixed size is then subjected to dehydration treatment to remove water from the channels inside the membrane, and then soaked in n-hexane for later use.

2. The method for preparing an ordered nanochannel polymer separation membrane based on dual continuous lyotropic liquid crystals according to claim 1, characterized in that... The monomer containing polymerizable groups in step 1) above is methacryloyl chloride.

3. The method for preparing an ordered nanochannel polymer separation membrane based on a dual-continuous lyotropic liquid crystal according to claim 1, characterized in that... The mixed reaction solvent in steps 1-2 above is toluene:acetonitrile = 1:

1.

4. The method for preparing an ordered nanochannel polymer separation membrane based on a dual-continuous lyotropic liquid crystal according to claim 1, characterized in that... In step 1) above, tartaric acid is used as a reactant for ion exchange.

5. The method for preparing an ordered nanochannel polymer separation membrane based on dual continuous lyotropic liquid crystals according to claim 1, characterized in that... In step 2) above, the speed of the high-speed centrifuge is 15000 rpm / min.

6. The method for preparing an ordered nanochannel polymer separation membrane based on dual continuous lyotropic liquid crystals according to claim 1, characterized in that... In step 3) above, the photoinitiator is 2-hydroxy-2-methylpropionyl phenyl ketone, with a content of 1 wt%.

7. The method for preparing an ordered nanochannel polymer separation membrane based on a dual-continuous lyotropic liquid crystal according to claim 1, characterized in that... The UV curing conditions in step 3) above are: light source 365nm, curing temperature 25℃, and luminous flux 800 mW / cm². 2 The curing time is 100 seconds.

8. The method for preparing an ordered nanochannel polymer separation membrane based on a dual-continuous lyotropic liquid crystal according to claim 1, characterized in that... In step 4) above, the membrane is initially dehydrated and then vacuum dried after being soaked in ethanol for 12 hours.

9. An ordered nanochannel polymer separation membrane obtained by the preparation method according to any one of claims 1-8.

10. An application of an ordered nanochannel polymer separation membrane, characterized in that... Used for the separation of racemic mixtures, especially suitable for the enantioselective separation of racemic chiral drugs.

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