Crosslinkable and charged zwitterionic polymers, and membranes containing the same

Abstract

The present invention generally relates to a polymeric material designed to produce membranes with improved selectivity and fouling resistance, having, for example, an adjustable effective pore size reducible to <1 nm, excellent fouling resistance, improved chemical and thermal stability, and potential capabilities including ion selectivity. In particular, the present invention relates to crosslinkable and charged zwitterionic polymers, and membranes made therefrom for reverse osmosis applications.

Description

Cross - reference to related applications

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 364,755, filed May 16, 2022, the disclosure of which is hereby incorporated by reference in its entirety.

Technical Field

[0002] The present disclosure generally relates to cross - linkable and charged zwitterionic polymers for reverse osmosis applications and membranes made therefrom.

Background Art

[0003] Membrane filtration is an important and promising method for water purification, regeneration, and reuse. Membranes with various pore sizes can be used for a wide range of purposes, from simply removing pathogenic microorganisms to desalination by reverse osmosis (RO). Membranes also serve as efficient and simple scalable separation methods in various industries such as food, beverage, dairy, and bio / pharmaceutical industries.

[0004] Membranes having improved selectivity, or the ability to separate solutes with better precision, result in improved economic viability and energy efficiency of several other processes. For example, a membrane with improved selectivity between sulfate anions and chloride anions can change the composition of seawater and wastewater for use as drilling fluids in offshore oil wells while operating at a lower applied pressure. Membranes with extremely small pore sizes but low salt rejection can significantly improve the drainage quality of difficult waste streams, especially those with high organic content such as waste streams from the food industry.

[0005] All of the above membrane processes are often severely affected by fouling, which is defined as the deterioration of membrane performance due to the adsorption and accumulation of feed components on the membrane surface. A significant decrease in membrane permeability and a change in membrane selectivity are common. Fouling management is an important element of the costs associated with membrane systems and requires an increase in energy usage, regular cleaning with downtime, maintenance and the use of chemicals, and more complex processes. SUMMARY OF THE INVENTION MEANS FOR SOLVING THE PROBLEM

[0006] Provided herein is a polymeric material designed to produce membranes having improved selectivity and fouling resistance, the polymeric material having an adjustable effective pore size reducible to <1 nm, excellent fouling resistance, improved chemical resistance and thermal stability, and potential capabilities including ion selectivity.

[0007] In various embodiments, the present disclosure relates to zwitterionic polymers and membranes made therefrom. The present disclosure includes, but is not limited to, the following exemplary implementations.

[0008] Embodiment 1: A copolymer comprising a plurality of first repeating units, a plurality of second repeating units, and a plurality of third repeating units, wherein the first repeating unit is zwitterionic; at least a portion of the second repeating units each independently includes a crosslinkable moiety; at least a portion of the third repeating units is ionizable; and the second repeating unit and the third repeating unit are different, the copolymer.

[0009] Embodiment 2: Each of the first repeating units is independently a copolymer of the foregoing embodiments containing a sulfobetaine group, a carboxybetaine group, a phosphorylcholine group, an imidazolium alkyl sulfonate group, a pyridinium alkyl sulfonate group, or a carboxybetaine group.

[0010] Embodiment 3: Each of the zwitterionic repeating units is independently a copolymer of Embodiment 1 or 2, or any combination thereof, formed from sulfobetaine acrylate, sulfobetaine acrylamide, carboxybetaine acrylate, carboxybetaine methacrylate, 2-methacryloyloxyethyl phosphorylcholine, acryloxy phosphorylcholine, phosphorylcholine acrylamide, phosphorylcholine methacrylamide, carboxybetaine acrylamide, carboxybetaine vinyl pyridine, carboxybetaine vinyl imidazole, 3-(2-vinylpyridinium-1-yl)propane-1-sulfonate, 3-(4-vinylpyridinium-1-yl)propane-1-sulfonate, sulfobetaine methacrylate, or a combination thereof.

[0011] Embodiment 4: The copolymer according to any one of Embodiments 1 to 3, or any combination thereof, wherein at least a part of the second repeating unit contains a hydrophobic repeating unit.

[0012] Embodiment 5: The copolymer according to any one of Embodiments 1 to 4, or any combination thereof, wherein at least a part of the second repeating unit contains a hydrophilic repeating unit.

[0013] Embodiment 6: The hydrophobic repeating unit is independently formed from styrene, alkyl acrylate, alkyl methacrylate, alkyl acrylamide, acrylonitrile, aryl acrylate, aryl methacrylate, aryl acrylamide, allyl acrylate, allyl acrylamide, allyl methacrylamide, vinyl methacrylate, vinyl methacrylamide, vinyl acrylamide, allyl vinyl benzene (styrene derivative), cinnamate, benzophenone, isopropyl thioxanthone, or a combination thereof, the copolymer according to any one of Embodiments 1 to 5, or any combination thereof.

[0014] Embodiment 7: The second part of the second repeating unit contains a second type of hydrophobic repeating unit, the copolymer according to any one of Embodiments 1 to 6, or any combination thereof.

[0015] Embodiment 8: The second type of hydrophobic repeating unit is independently formed from alkyl acrylate, alkyl methacrylate, alkyl acrylamide, acrylonitrile, aryl acrylate, aryl methacrylate, aryl acrylamide, trifluoroethyl methacrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, acrylonitrile, styrene, or a combination thereof, the copolymer according to any one of Embodiments 1 to 7, or any combination thereof.

[0016] Embodiment 9: At least a part of the second repeating unit does not contain a crosslinkable moiety, the copolymer according to any one of Embodiments 1 to 8, or any combination thereof.

[0017] Embodiment 10: The second repeating unit that does not contain a crosslinkable moiety is, independently of each other, acrylate, methacrylate, acrylamide, methacrylamide, trifluoroethyl methacrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, acrylonitrile, styrene, or a combination thereof, the copolymer according to any one of Embodiments 1 to 9, or any combination thereof.

[0018] Embodiment 11: The crosslinkable moiety contains a carbon-carbon double bond, the copolymer according to any one of Embodiments 1 to 10, or any combination thereof.

[0019] Embodiment 12: The crosslinkable moiety contains allyl (CH 2 -CH=CH 2 ), vinyl (-CH=CH 2 or -CH=CH-), vinyl ether (-O-CH=CH 2 ), or vinyl ester (-CO-O-CH=CH 2 ), the copolymer according to any one of Embodiments 1 to 11, or any combination thereof.

[0020] Embodiment 13: The crosslinkable moiety is polymerized (e.g., crosslinked) through exposure to one or more of a free radical photoinitiator, electromagnetic radiation (e.g., UV light or electron beam, etc.), high temperature, redox reaction, or a combination thereof, the copolymer according to any one of Embodiments 1 to 12, or any combination thereof.

[0021] Embodiment 14: Each of the ionizable third repeating units is independently selected from 3-sulfopropyl methacrylate potassium salt; methacrylate, acrylate, acrylamide, styrene derivatives containing one or more of carboxylate, carboxylic acid, sulfonate, sulfonic acid, amine, amino acid, phosphate, phosphonic acid, phosphonium, boronate, or boronic acid; or combinations thereof, the copolymer according to any one of Embodiments 1 to 13, or any combination thereof.

[0022] Embodiment 15: The copolymer has a molecular weight of about 10,000 to about 10,000,000 Daltons, preferably about 20,000 to about 500,000 Daltons, more preferably about 20,000 to about 100,000 Daltons, the copolymer according to any one of Embodiments 1 to 14, or any combination thereof. Generally, the specific molecular weight of the copolymer is selected to be suitable for a particular application.

[0023] Embodiment 16: The first repeating unit constitutes about 5 to about 95% by weight, preferably about 10 to about 90% by weight, more preferably about 20 to about 80% by weight, even more preferably about 25 to about 75% by weight of the copolymer, the copolymer according to any one of Embodiments 1 to 15, or any combination thereof.

[0024] Embodiment 17: The second repeating unit constitutes about 5 to about 95% by weight, preferably about 10 to about 90% by weight, more preferably about 20 to about 80% by weight, even more preferably about 25 to about 75% by weight of the copolymer, the copolymer according to any one of Embodiments 1 to 16, or any combination thereof.

[0025] Embodiment 18: The third repeating unit constitutes about 5% to about 95% by weight of the copolymer, preferably about 10% to about 90% by weight, more preferably about 20% to about 80% by weight, and even more preferably about 25% to about 75% by weight of the copolymer described in any one of Embodiments 1 to 17, or any combination thereof. Generally, the specific combination of monomers and their weight ranges vary to suit a particular application.

[0026] Embodiment 19: A crosslinked copolymer network comprising the copolymer described in any one of Embodiments 1 to 18, or any combination thereof.

[0027] Embodiment 20: A thin film composite membrane comprising a porous substrate and a selective layer comprising the crosslinked copolymer network of Embodiment 19.

[0028] Embodiment 21: The membrane according to the previous embodiments, wherein the average effective pore size of the porous substrate is larger than the average effective pore size of the selective layer.

[0029] Embodiment 22: The membrane of Embodiment 20 or 21, or any combination thereof, wherein the selective layer is disposed on the porous substrate.

[0030] Embodiment 23: The membrane according to any one of Embodiments 20 to 22, or any combination thereof, wherein the selective layer has an average effective pore size of about 0.1 nm to about 2.0 nm.

[0031] Embodiment 24: The membrane according to any one of Embodiments 20 to 23, or any combination thereof, wherein the selective layer has an average effective pore size of about 0.1 nm to about 1.2 nm.

[0032] Embodiment 25: The membrane according to any one of Embodiments 20 to 24, or any combination thereof, wherein the selective layer has an average effective pore size of about 0.5 nm to about 1.0 nm.

[0033] Embodiment 26: The selective layer is a film according to any one of Embodiments 20 to 25 having a thickness of about 10 nm to about 10 μm, or any combination thereof.

[0034] Embodiment 27: The selective layer is a film according to any one of Embodiments 20 to 26 having a thickness of about 100 nm to about 2 μm, or any combination thereof.

[0035] Embodiment 28: The thin-film composite membrane is a membrane according to any one of Embodiments 20 to 27 that blocks charged solutes and salts, or any combination thereof.

[0036] Embodiment 29: The selective layer is a film according to any one of Embodiments 20 to 28 that exhibits a sulfate (SO 4 2- ) rejection rate of more than 99%, or any combination thereof.

[0037] Embodiment 30: The selective layer is a film according to any one of Embodiments 20 to 29 that exhibits a sulfate (SO 4 2- ) / chloride (Cl - ) separation factor greater than 50, or any combination thereof.

[0038] Embodiment 31: The selective layer is a film according to any one of Embodiments 20 to 30 that exhibits a sulfate (SO 4 2- ) / chloride (Cl - ) separation factor of about 75, or any combination thereof.

[0039] Embodiment 32: The selective layer is a film according to any one of Embodiments 20 to 31 that exhibits different anion rejection rates for salts having the same cation, or any combination thereof.

[0040] Embodiment 33: The selective layer is NaF, NaCl, NaBr, NaI, and NaClO 4The membrane according to any one of Embodiments 20 to 32, or any combination thereof, which exhibits different anion rejection rates with respect to salts selected therefrom.

[0041] Embodiment 34: The selective layer is the membrane according to any one of Embodiments 20 to 33, or any combination thereof, which exhibits a fluoride (F - ) / chloride (Cl - ) separation factor greater than 5.

[0042] Embodiment 35: The selective layer is the membrane according to any one of Embodiments 20 to 34, or any combination thereof, which exhibits a fluoride (F - ) / chloride (Cl - ) separation factor of about 8.

[0043] Embodiment 36: The selective layer is the membrane according to any one of Embodiments 20 to 35, or any combination thereof, which exhibits different rejection rates with respect to monosaccharides and disaccharides.

[0044] Embodiment 37: The selective layer is the membrane according to any one of Embodiments 20 to 36, or any combination thereof, which exhibits a glucose / sucrose separation factor greater than 10.

[0045] Embodiment 38: The selective layer is the membrane according to any one of Embodiments 20 to 37, or any combination thereof, which exhibits a xylose / sucrose separation factor greater than 18.

[0046] Embodiment 39: The selective layer is the membrane according to any one of Embodiments 20 to 38, or any combination thereof, which exhibits resistance to fouling by oil emulsions.

[0047] Embodiment 40: The selective layer is the membrane according to any one of Embodiments 20 to 39, or any combination thereof, which is stable when exposed to a chlorine bleach (e.g., pH 4).

[0048] Embodiment 41: The selective layer is the membrane according to any one of Embodiments 20 to 40, or any combination thereof, which exhibits selectivity based on the size between uncharged organic molecules.

[0049] Embodiment 42: The selective layer is the membrane according to any one of Embodiments 20 to 41, or any combination thereof, which exhibits a rejection rate of >99% for neutral molecules having a hydration diameter of about 1 nm or more.

[0050] Embodiment 43: A method for producing a thin-film composite membrane, comprising the steps of providing a copolymer according to any one of Embodiments 1 to 18, or any combination thereof; depositing the copolymer on a porous substrate; and activating the crosslinkable groups of the copolymer to form further bonds therebetween. Embodiment 44: The step of activating the crosslinkable groups of the copolymer includes one or more of exposing the membrane to a free-radical photoinitiator, electromagnetic radiation, a free-radical photoinitiator and a dithiol, or a combination thereof, in the method for producing the membrane of the foregoing embodiments.

[0051] Embodiment 45: The step of exposing the membrane to a free-radical photoinitiator includes exposing the membrane to a solvent containing a free-radical photoinitiator and / or a solvent containing a free-radical photoinitiator and a dithiol, in the method for producing the membrane according to Embodiment 43 or 44, or any combination thereof. Exposing the membrane to a solvent may include, for example, immersing, dipping, coating, rinsing, or otherwise wetting a target portion of the membrane (e.g., the crosslinkable groups of the copolymer).

[0052] Embodiment 46: The step of exposing the membrane to electromagnetic radiation includes exposing the membrane to ultraviolet light, an electron beam, or otherwise irradiating a target portion of the membrane (e.g., the crosslinkable groups of the copolymer), in the method for producing the membrane according to Embodiments 43 to 45, or any combination thereof.

[0053] Generally, additional processing steps such as, for example, quenching, surface modification, cleaning, inactivation, etc. are contemplated and considered to be within the scope of the present invention and can be carried out with different solvents, radiation ranges, and processing times.

[0054] These and other features, aspects, and advantages of the present disclosure will become apparent by reading the following detailed description in conjunction with the accompanying drawings, which are briefly described below. The present invention encompasses any combination of two, three, four, or more of the above-described embodiments, as well as any combination of two, three, four, or more features or elements described in the present disclosure, whether or not such features or elements are explicitly combined in the description of a particular embodiment herein. The present disclosure is intended to be read as a whole such that any separable features or elements of the disclosed invention are considered combinable in any of its various aspects and embodiments, unless the context clearly dictates otherwise.

MODE FOR CARRYING OUT THE INVENTION

[0055] A family of polymer materials is disclosed that includes at least three types of repeating units: crosslinkable monomers, zwitterionic monomers, and ionic or ionizable monomers. The present disclosure enables the easy preparation of reverse osmosis membranes having novel polymer chemistries. These membranes preferably have improved fouling resistance, chlorine resistance, and stability (e.g., against chemical or thermal damage).

[0056] Cross-linkable monomer: A typical cross-linkable moiety is a C=C double bond, which can polymerize when exposed to a free radical photoinitiator and is activated by ultraviolet (UV) light or an electron beam. It may also be possible to do this using thermal methods (i.e., using an initiator activated at a higher temperature) or by a redox reaction. The cross-linkable moiety need not be a C=C double bond and can instead be polymerized by exposure to UV light in the absence of a radical initiator.

[0057] Zwitterionic monomer: It plays a role in imparting water permeability and fouling resistance to the membrane selective layer.

[0058] Ionic or ionizable monomer: When the monomer is ionic, it has a net charge over a given range of pH, preferably, but not necessarily, over a wide range of pH. When the monomer is ionizable, it is initially neutral but can acquire a net charge over a given pH range by some ionization reaction (e.g., deprotonation or protonation). Ionic or ionizable monomers are referred to herein as ionic / ionizable monomers.

[0059] The material can also include additional hydrophobic repeating units that are not cross-linkable. This additional hydrophobic repeating unit can be an acrylate, methacrylate, acrylamide, methacrylamide, or styrene derivative. Some examples of additional hydrophobic repeating units include trifluoroethyl methacrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, acrylonitrile, and styrene.

[0060] Generally, these copolymers can be synthesized by methods well known in polymer science. When the crosslinkable group contains a C═C double bond such as a vinyl group or an allyl group, this copolymer can be prepared by controlled free radical methods that interact only with more reactive polymerizable groups, such as atom transfer radical polymerization (ATRP), and modified versions thereof such as atom regeneration transfer ATRP (ARGET-ATRP), nitroxide-mediated polymerization (NMP), or reversible addition fragmentation transfer (RAFT) polymerization. It may also be possible to prepare these polymers using conventional free radical polymerization while carefully controlling the polymerization conditions (e.g., highly diluted solutions, low conversions).

[0061] In various embodiments, the copolymer is a statistical copolymer and can incorporate different types of repeating units in a substantially random order (as opposed to blocks). Further, the copolymer may be mostly linear in structure. In certain embodiments, the copolymer is linear. In certain embodiments, the copolymer is branched.

[0062] In various embodiments, the copolymer can have a molecular weight greater than 5,000 g / mol, preferably greater than 30,000 g / mol, and even more preferably greater than 100,000 g / mol.

[0063] In various embodiments, the copolymer contains zwitterionic repeating units at a concentration of 10 to 90 wt%, more preferably 20 to 80 wt%, and even more preferably 25 to 75 wt%.

[0064] In one embodiment, all hydrophobic repeating units are crosslinkable. In another embodiment, three monomers: a crosslinkable monomer, a non-crosslinkable hydrophobic monomer, and a zwitterionic monomer: are used.

[0065] In one example, allyl methacrylate (AMA) is used as the crosslinkable monomer. Allyl (CH 2 -CH=CH 2 ), vinyl (-CH=CH 2 or -CH=CH-), vinyl ether (-O-CH=CH 2 ), and vinyl ester (-CO-O-CH=CH 2 ) groups, other acrylates, methacrylates, acrylamides, methacrylamides, and styrene derivatives are also suitable for similar processes. These functional groups are polymerizable by free radical polymerization, but are significantly less reactive than acrylate, methacrylate, styrene, acrylamide, and methacrylamide groups, particularly in the controlled free radical polymerization methods described herein. Some possible crosslinkable monomers include, but are not limited to: allyl acrylate, allyl acrylamide, allyl methacrylamide, vinyl methacrylate, vinyl methacrylamide, vinyl acrylamide, allyl vinyl benzene (styrene derivative), other alkenyl acrylates / methacrylates / acrylamides / styrenes (e.g., undecenyl acrylate), and other monomers having double bond-containing side groups (e.g., ethylene glycol dicyclopentenyl ether methacrylate, ethylene glycol dicyclopentenyl ether acrylate). Further monomers that can undergo crosslinking include cinnamate (C 6 H 5 CH=CHCO 2 ), benzophenone ((C 6 H 5 ) 2 CO), and isopropyl thioxanthone (C 16 H 14Examples include acrylates, methacrylates, acrylamides, methacrylamides, and styrene derivatives, including OS). All three of these side groups can be crosslinked by ultraviolet treatment without using a radical initiator, and the last two of these side groups can potentially be used in combination with a synergist such as a tertiary amine.

[0066] In the same example, sulfobetaine methacrylate (SBMA) was used as the zwitterionic monomer. However, there are a wide range of viable zwitterionic monomers. Monomers containing sulfobetaine, phosphorylcholine, and carboxybetaine groups bonded to acrylates, methacrylates, acrylamides, methacrylamides, vinylpyridines, vinylimidazoles, and many other polymerizable groups are viable options.

[0067] In the same example, potassium 3-sulfopropyl methacrylate (SPMA) was used as the ionic / ionizable monomer. Other examples of ionic / ionizable monomers include methacrylates, acrylates, acrylamides, or styrene derivatives containing carboxylates, carboxylic acids, sulfonates, sulfonic acids, amines, aminos, phosphates, phosphonic acids, phosphonium, boronate, boronic acids, or other ionic / ionizable groups. The ionic / ionizable group may contain multiple ionic or ionizable groups such that the charge of the molecule is +2 or more for a cation or -2 or less for an anion.

[0068] When used, the non-crosslinkable hydrophobic monomers can be selected from a wide range. The homopolymers formed from the preferred monomers are insoluble in water under the operating conditions. Fluoroalkyl and alkyl-substituted, as well as fluoroaryl and aryl-substituted acrylates, methacrylates, acrylamides and methacrylamides, styrenes and their derivatives, acrylonitriles and methacrylonitriles are all viable options for this hydrophobic monomer. In some embodiments, the homopolymer of this hydrophobic monomer has a glass transition temperature higher than 0 °C, but this is not essential. The inventors have used trifluoromethyl methacrylate (TFEMA) for this purpose.

[0069] To form the membrane, these copolymers are coated onto the porous support by methods well understood in the membrane industry (e.g., doctor blade coating, spray coating). Upon deposition, the zwitterionic groups and the ionic / ionizable groups are expected to form clusters by Coulombic interactions.

[0070] After this membrane is formed, the crosslinkable groups on the copolymer chains are activated to form additional bonds between them. In one embodiment, this is done by first exposing the membrane to a solvent containing a free radical photoinitiator and then exposing the membrane to ultraviolet light and / or an electron beam. This activates the double bonds on the copolymer and creates bonds between the polymer chains. In another embodiment, this is done by first exposing the membrane to a solvent containing a free radical photoinitiator and a dithiol and then exposing the membrane to ultraviolet light and / or an electron beam. This activates the double bonds on the copolymer and creates bonds between the polymer chains. The dithiol serves to accelerate the crosslinking reaction rate.

[0071] Other possible crosslinking approaches include: exposing the coated membrane to electromagnetic radiation (e.g., UV light) without using a solvent during crosslinking (e.g., the photoinitiator can be added to the solution in which the copolymer is coated on the support); using a thermal free radical initiator instead of a photoinitiator and crosslinking by exposing to high temperature; using high-intensity UV without a photoinitiator; thermal crosslinking without an initiator; and / or using a redox initiator instead of a photoinitiator.

[0072] Upon crosslinking, the membrane selective layer has enhanced chemical and physical stability. The performance of the layer is expected to remain stable through a wider operating window, enabling use at higher temperatures and / or with more complex feeds containing higher salt concentrations, some solvents, etc.

[0073] The crosslinking process can also be used to adjust and improve the selectivity of the membrane. Specifically, during crosslinking, exposing the membrane to a solvent that preferentially swells the hydrophobic domain rather than the zwitterionic domain can reduce the effective pore size of the membrane, as measured using the rejection rate of sugar molecules, to low values of <1 nm, 0.74 nm, and in some cases even lower.

[0074] Further details regarding the manufacture of the membranes disclosed herein can be found in PCT Publications WO2021 / 232018 and WO2020 / 231797, as well as the following references: Lounder, S. J., Asatekin, A. Zwitterionic Ion-Selective Membranes with Tunable Subnanometer Pores and Excellent Fouling Resistance. Chem. Mater. 2021, 33, 12, 4408-4416 and Lounder, S. J., Asatekin, A. Interaction-Based Ion Selectivity Exhibited by Self-Assembled, Cross-Linked Zwitterionic Copolymer Membranes. Proc Natl Acad Sci USA (In Proof, 2021): the entire disclosures of which are incorporated herein by reference.

Example

[0075] To better understand the invention described herein, the following examples are provided. The examples described in this application are provided to illustrate the compounds, compositions, materials, devices, and methods provided herein and should in no way be construed as limiting their scope.

[0076] Synthesis of polymer: A copolymer of allyl methacrylate (AMA), sulfobetaine methacrylate (SBMA), and potassium 3-sulfopropyl methacrylate (SPMA) was synthesized by the activator regenerated by electron transfer atom transfer radical polymerization (ARGET-ATRP). Table 1 summarizes the different reaction solution compositions utilized for the success of the ARGET-ATRP synthesis:

Table 1

[0077] Manufacture of membrane The TFC membranes were prepared using the three copolymers (P1, P2, and P3) tabulated above. To prepare the TFC membranes, a given copolymer was first dissolved in trifluoroethanol (TFE) at 5.0 w / v% (i.e., 5 g of polymer / 95 mL of TFE). The solution was then passed through a syringe filter and coated onto a support membrane (UE50, Trisep) using a wire wound rod (Gardo, No. 16 wire size). The coated membrane was then transferred to a convection oven at 80 °C to evaporate the solvent.

[0078] Crosslinking of membrane Membrane disks were cut out from the prepared TFC membrane sheets and equilibrated with a UV-active solution consisting of isopropyl alcohol (IPA) and a UV-active component. To initiate the crosslinking reaction, the membrane disks were then irradiated with UV light (365 nm) for 2 - 20 minutes. This caused photopolymerization of the AMA groups and resulted in extensive membrane crosslinking for pore size reduction.

[0079] The UV-active component for a given crosslinking reaction was either: (1) a photoinitiator; or (2) a photoinitiator together with a dithiol crosslinking accelerator. The UV-active components investigated were as follows: 2-hydroxy-2-methylpropiophenone (HOMP); 2,2-dimethoxy-2-phenylacetophenone (DPMA); and 1,6-hexanedithiol (HDT). The composition of the UV-active solution is summarized in Table 2 below.

Table 2

[0080] The foregoing specification is considered to be sufficient for those skilled in the art to practice the present invention. The examples are intended as merely illustrative of one aspect of the present invention, and since other functionally equivalent embodiments are within the scope of the present invention, the present invention is not limited in scope by the examples provided. In addition to what is shown and described herein, various modifications of the present invention will be apparent to those skilled in the art from the foregoing description and fall within the scope of the appended claims. The advantages and objectives of the present invention are not necessarily included in each embodiment of the present invention.

Claims

1. A copolymer comprising a plurality of first repeating units, a plurality of second repeating units, and a plurality of third repeating units, The first repeating unit is a zwitterionic repeating unit; At least a portion of the second repeating unit each independently includes a crosslinkable portion; At least a portion of the third repeating unit is ionizable; The copolymer wherein the second repeating unit and the third repeating unit are different.

2. The copolymer according to claim 1, wherein each of the first repeating units independently comprises a sulfobetaine group, a carboxybetaine group, a phosphorylcholine group, an imidazolium alkyl sulfonate group, a pyridinium alkyl sulfonate group, or a carboxybetaine group.

3. The copolymer according to claim 1, wherein each of the zwitterionic repeating units is independently formed from sulfobetaine acrylate, sulfobetaine acrylamide, carboxybetaine acrylate, carboxybetaine methacrylate, 2-methacryloyloxyethyl phosphorylcholine, acrylooxyphosphorylcholine, phosphorylcholine acrylamide, phosphorylcholine methacrylamide, carboxybetaine acrylamide, carboxybetaine vinylpyridine, carboxybetaine vinylimidazole, 3-(2-vinylpyridinium-l-yl)propane-l-sulfonate, 3-(4-vinylpyridinium-l-yl)propane-l-sulfonate, sulfobetaine methacrylate, or a combination thereof.

4. The copolymer according to claim 1, wherein at least a portion of the second repeating unit includes a hydrophobic repeating unit.

5. The copolymer according to claim 1, wherein at least a portion of the second repeating unit includes a hydrophilic repeating unit.

6. The copolymer according to claim 4, wherein the hydrophobic repeating units are independently formed from styrene, alkyl acrylate, alkyl methacrylate, alkyl acrylamide, acrylonitrile, aryl acrylate, aryl methacrylate, aryl acrylamide, allyl acrylate, allyl acrylamide, allyl methacrylamide, vinyl methacrylate, vinyl methacrylamide, vinyl acrylamide, allyl vinylbenzene (styrene derivative), cinnamate, benzophenone, isopropylthioxanthone, or a combination thereof.

7. The copolymer according to claim 4, wherein the second portion of the second repeating unit comprises a second type of hydrophobic repeating unit.

8. The copolymer according to claim 7, wherein each of the second type of hydrophobic repeating units is independently formed from alkyl acrylate, alkyl methacrylate, alkyl acrylamide, acrylonitrile, aryl acrylate, aryl methacrylate, aryl acrylamide, trifluoroethyl methacrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, acrylonitrile, styrene, or a combination thereof.

9. The copolymer according to claim 1, wherein at least a portion of the second repeating unit does not contain a crosslinkable portion.

10. The copolymer according to claim 9, wherein each second repeating unit, which does not contain a crosslinkable portion, is independently formed from acrylate, methacrylate, acrylamide, methacrylamide, trifluoroethyl methacrylate, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, acrylonitrile, styrene, or a combination thereof.

11. The copolymer according to claim 1, wherein the crosslinkable portion includes a carbon-carbon double bond.

12. The aforementioned crosslinkable portion is allyl (CH ２ -CH=CH ２ ), vinyl (-CH=CH ２ Or -CH=CH-), vinyl ether (-O-CH=CH ２ ), or vinyl ester (-CO-O-CH=CH ２ The copolymer according to claim 11, comprising )

13. The copolymer according to claim 1, wherein the crosslinkable portion is polymerized by exposure to one or more of the following: a free radical photoinitiator, electromagnetic radiation, high temperature, a redox reaction, or a combination thereof.

14. The copolymer according to claim 1, wherein each of the ionizable third repeating units is independently formed from a methacrylate, acrylate, acrylamide, styrene derivative, or a combination thereof, comprising one or more of the following: 3-sulfopropyl methacrylate potassium salt; carboxylate, carboxylic acid, sulfonate, sulfonic acid, amine, amino acid, phosphate, phosphonic acid, phosphonium, boronic acid, or boronic acid.

15. The copolymer according to claim 1, having a molecular weight of approximately 10,000 to approximately 10,000,000 Daltons.

16. The first repeating unit constitutes about 5 to about 95% by weight of the copolymer, or The second repeating unit constitutes approximately 5 to approximately 95% by weight of the copolymer, or The copolymer according to claim 1, wherein the third repeating unit constitutes about 5 to about 95% by weight of the copolymer.

17. A crosslinked copolymer network comprising the copolymer described in any one of claims 1 to 16.

18. Porous substrates; and Selective layer comprising the crosslinked copolymer network described in claim 17 A thin-film composite film containing [a specific component].

19. The thin film composite film according to claim 18, wherein the average effective pore diameter of the porous substrate is larger than the average effective pore diameter of the selected layer.

20. The thin film composite film according to claim 18, wherein the selected layer is disposed on a porous substrate.

21. The selected layer has an average effective pore size of about 0.1 nm to about 2.0 nm, and / or The thin film composite film according to claim 18, wherein the selected layer has a thickness of about 10 nm to about 10 μm.

22. A thin-film composite film according to claim 18, which prevents charged solutes and salts.

23. The aforementioned selective layer contains more than 99% sulfate (SO4). ４ ２－ ) Shows the blocking rate, and / or The selective layer exhibits a sulfate (SO₄²⁻) / chloride (Cl⁻) separation coefficient greater than 50, and / or The selective layer exhibits different anion rejection rates for salts having the same cation, and / or The selective layer exhibits different anion rejection rates for salts selected from NaF, NaCl, NaBr, NaI, and NaClO4, and / or The selective layer exhibits a fluoride (F-) / chloride (Cl-) separation coefficient greater than 5, and / or The selective layer exhibits different rejection rates for monosaccharides and disaccharides, and / or The selective layer exhibits a glucose / sucrose separation coefficient greater than 10, and / or The selective layer exhibits a xylose / sucrose separation coefficient greater than 18, and / or The selected layer exhibits resistance to fouling by oil emulsions, and / or The selected layer is stable when exposed to a chlorine bleach, and / or The selective layer exhibits selectivity based on the size of uncharged organic molecules, and / or The thin film composite film according to claim 18, wherein the selective layer exhibits a rejection rate of more than 99% against neutral molecules having a hydration diameter of about 1 nm or more.

24. A method for fabricating thin-film composite films, A step of providing the copolymer according to any one of claims 1 to 16; The step of depositing the copolymer onto a porous substrate; and The step of activating the crosslinkable groups of the copolymer to form further bonds between them. The method, including the method described above.

25. The method according to claim 24, wherein the step of activating the crosslinkable groups of the copolymer comprises one or more of exposing the film to a free radical photoinitiator, electromagnetic radiation, a free radical photoinitiator and a dithiol, or a combination thereof.

26. Exposure of a film to a free radical photoinitiator includes exposing the film to a solvent containing a free radical photoinitiator and / or a solvent containing a free radical photoinitiator and a dithiol. The method according to claim 25, wherein exposing the film to electromagnetic radiation includes exposing the film to ultraviolet and / or electron beams.