WO2025207549A1 - Methods to fabricate membranes using additive manufacturing - Google Patents

Abstract

In one aspect, the disclosure relates to a method for making a polymeric membrane using an additive manufacturing technique. The method produces defect-free membranes and uses at least 60% less solvent than conventional techniques. Also disclosed herein are membranes produced using the method and methods of using the membranes for liquid, vapor, and gas separation processes. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present disclosure.

Description

METHODS TO FABRICATE MEMBRANES USING ADDITIVE MANUFACTURING

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application Ser. No. 63/569,250, filed March 25, 2024, which is incorporated herein by reference in its entirety.

BACKGROUND

[0002] Membranes for liquid, vapor, and gas separation serve as important components for many modern manufacturing and purification processes, with applications including water treatment, carbon capture and organic solvent separation. Membranes typically consume significantly less energy compared to other separation processes and are poised to play an important role in industrial decarbonization efforts. In addition, the emergence of new contaminants, such as perfluoroalkyl substances, require specifically tailored membranes. Emerging applications thus provide opportunities to not only design new membrane materials, but also to develop sustainable membrane manufacturing strategies.

[0003] Traditionally, flat sheet water treatment membranes are fabricated via film casting of polymer dope solutions as the precursor, the underlying mechanism being non-solvent induced phase separation. Typically, these fabrication processes require large volumes of solvents including toxic solvents such as dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), and the like, which have been banned in Europe. Therefore, it would be desirable to develop an approach to membrane fabrication that requires lower solvent volumes.

[0004] Doctor blade technology is another common method of manufacture for separation membranes. However, doctor blades wear down quickly and frequently need to be replaced, which adds to the cost of membrane manufacture. Furthermore, doctor blade technology offers limited design flexibility in terms of membrane geometry and pore structure and is limited in scalability. Doctor blade processes also often generate significant amounts of material waste. It would thus be desirable to develop a method of membrane manufacturing that produces membranes performing as well as, or better than, membranes produced by the doctor blade method without the disadvantages associated with doctor blades.

[0005] Despite advances in membrane production research, there is still a scarcity of methods for producing membranes for liquid, vapor, and gas separation purposes that require low solvent volumes and do not rely on methods of manufacture that require frequent replacement of costly parts. The membranes produced by such methods should be defect free and should meet or exceed performance benchmarks for membranes produced by current technologies. In a still further aspect, such a method could be customized to produce membranes suited for a variety of purposes. These needs and other needs are satisfied by the present disclosure.

SUMMARY

[0006] In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, the disclosure, in one aspect, relates to a method for making a polymeric membrane using an additive manufacturing technique. The method produces defect-free membranes and uses at least 60% less solvent than conventional techniques. Also disclosed herein are membranes produced using the method and methods of using the membranes for liquid, vapor, and gas separation processes.

[0007] Other systems, methods, features, and advantages of the present disclosure will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional systems, methods, features, and advantages be included within this description, be within the scope of the present disclosure, and be protected by the accompanying claims. In addition, all optional and preferred features and modifications of the described embodiments are usable in all aspects of the disclosure taught herein. Furthermore, the individual features of the dependent claims, as well as all optional and preferred features and modifications of the described embodiments are combinable and interchangeable with one another.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Many aspects of the present disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views.

[0009] FIGs. 1A-1C show the direct ink writing fabrication process for polysulfone (PSf) membrane films. A dope solution of PSf and DMAc is mixed (FIG. 1 A) and loaded into a syringe barrel for patterning of the polymer solution on substrate (FIG. 1B). Following printing, the dope solution and substrate are submerged into water to quench and solidify the membrane through phase inversion (13 x 7 cm) (FIG. 10).

[0010] FIGs. 2A-2B show the in situ phase inversion process during membrane fabrication via printing. (FIG. 2A) Partial humidity induced phase inversion of a printed polysulfone- DMAc film. The fully phase inverted sections are opaque and white in color while the non-phase inverted portions are transparent. (FIG. 2B) Example of fully formed membrane after non-solvent induced phase inversion (NIPS) process, distinguished by total opaqueness and uniform white color.

[0011] FIG. 3 shows a cross flow testing setup for determining pure water permeance for the fabricated membrane films.

[0012] FIG. 4 shows the impact of the substrate roughness on the occurrence and repeatability of defect formation in the printed polysulfone membranes. For the comparatively rough substrates such as the initially chosen glass slide, defects (i.e. holes) in the printed films occurred with regularity at specific positions on the substrate. While sanding the glass substrate reduced the surface roughness and mildly decreased the frequency of defect formation, transitioning to a polished silicon wafer (~2 orders of magnitude lower roughness) significantly eliminated the occurrence of these defects in the printed films.

[0013] FIG. 5 shows cross sectional and surface SEM images of the printed and doctor bladed membranes both before and after pure water permeance testing. The scale bar in each image is 50 pm. The tested direct ink writing (DIW) membranes have a width of 125 pm and the tested doctor bladed membrane is 119 pm.

[0014] FIGs. 6A-6B show pure water flux of (FIG. 6A) doctor bladed membranes and (FIG. 6B) DIW printing/direct ink written membranes. For the doctor bladed films, three samples (Dr-M1- M3) prepared under identical conditions were measured to determine the variability in the permeance performance. Similarly, six membranes (DIW-M1-M6) prepared via printing under identical conditions were used for the pure water permeance measurements.

[0015] FIG. 7 shows bovine serum albumin (BSA) solution permeance and accompanying BSA rejection percentage for both doctor bladed and DIW printed membranes. This data displays a relationship between the permeance and percent rejection.

[0016] FIG. 8 shows a schematic of the printing path used during the direct-ink writing process of polysulfone water separation membranes. The pattern is referred to as the “rectangular” print pattern. The number of lines in the schematic is representational only and does not reflect the actual number of passes required to fabricate the membrane films. [0017] FIG. 9 shows a robotic printing system with glove bag enclosure for modifying the relative humidity using a humidifier system.

[0018] FIG. 10 shows a BSA standard curve constructed in order to determine concentration of BSA in feed, permeate and retentate samples.

[0019] FIG. 11 shows the impact of humidity on the initial pure water flux, showing that 40% relative humidity gave the highest initial pure water flux.

[0020] FIG. 12 shows an SEM image of polysulfone DIW membrane fabricated under 20% RH.

[0021] FIG. 13 shows additional SEM images of the cross section of doctor bladed polysulfone membranes following testing to verify the occurrence of microvoids within the internal porous structure. The scale bar represents 100 pm.

[0022] FIGs. 14A-14L show histograms of pore sizes extracted from SEM images of different membranes.

[0023] FIGs. 15A-15B show pore distribution (Brunauer-Emmett-Teller or BET method) of tested (FIG. 15B) and untested (FIG. 15A) PSf/DMAc direct ink written membranes.

[0024] FIG. 16 shows pure water of DIW membranes processed using the solvent exchange procedure in an attempt to reduce or eliminate the flux decline over time.

[0025] FIGs. 17A-17C show evaluation of DIW PSf/NMP membranes for direct comparison purposes.

[0026] FIG. 18 shows SEM images for comparing the surface and cross section morphology for printed NMP membranes, both before and after pure water flux testing. The scale bars are 50 pm.

[0027] FIG. 19 shows DIW PSf/DMAc membrane performance in 20% RH with equal dwell time (9 min) as 40% RH samples.

[0028] FIG. 20 shows doctor blade PSF/NMP membrane permeance and BSA rejection results. The membranes underwent a nine minute dwell time in 40% RH.

[0029] Additional advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or can be learned by practice of the invention. The advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

DETAILED DESCRIPTION

[0030] Disclosed herein is an additive manufacturing-based technique for membrane fabrication. In one aspect, this technique facilitates precise control of the membrane fabrication process. In an aspect, direct ink writing (DIW) can be classified into three categories: continuous dropletbased, energy-assisted, and extrusion-based DIW. In a further aspect, disclosed herein is use of extrusion-based DIW. In a still further aspect, extrusion DIW is able to accommodate a wide range of viscosities and viscoelastic behavior suitable for polymer dope solutions, while requiring less specific equipment compared to the other mentioned techniques, such as nozzles for droplet based techniques. In another aspect, since DIW involves the pressure driven layer-by-layer deposition of a polymer ink through a nozzle, it can be used for membrane surface modification as well as membrane fabrication. In another aspect, the layer-by-layer approach allows for the creation of membranes with thin film composite asymmetric structures In one aspect, DIW involves the robotic deposition of a prepared solution (i.e., an ink) via the application of a driving force, commonly in the form of pneumatic pressure or mechanical devices such as screws. Further in this aspect, the deposited ink can have a diverse composition as well as a wide range of viscoelastic properties, with a reported upper viscosity limit being ~106 mPa-s at a shear rate of 0.1 S’¹. In a further aspect, following the DIW process, solvent evaporation begins to occur, which results in the precipitation of the solute molecule dissolved in the ink. In an aspect, by controlling the evaporation conditions which drive the solvent/solute separation, DIW/additive manufacturing can be implemented for membrane fabrication. In some aspects, DIW membranes can be constructed on substrates such as complex and/or inflexible materials such as, for example, ceramics, where traditional fabrication methods encounter challenges due to inert and/or stiff surfaces of the substrates. In still another aspect, DIW membranes can incorporate complex structures that are not possible to construct using doctor blades or other traditional processes. In still another aspect, because DIW can be used to print a selective layer modification by using a capillary force-driven process instead of a pressure-driven process for extruding the dope solution, DIW can fabricate membranes using solutions and non-traditional polymer systems that are typically unsuitable for membrane fabrication processes.

[0031] In one aspect, the disclosed additive manufacturing-based process is useful herein for the fabrication of porous polysulfone membranes as an alternative to traditional manufacturing methods. In a further aspect, the fabrication method described here synergizes the DI W technique with the non-solvent-induced phase inversion (NIPS) mechanism using a simple binary (polymer in solvent) ink. In an aspect, polysulfone was chosen since it is one of the most common membrane materials for liquid and gas separations. In another aspect, the disclosed method is scalable and repeatable and produces membranes having long-term stability. In yet another aspect, print speed, nozzle size, nozzle length, and pressure can all be adjusted to produce individual membranes suited for particular purposes. In some aspects, the nozzle apparatus can be tailored to produce specific types of membranes including, but not limited to, hollow fiber membranes.

[0032] In an aspect, the disclosed methods allow for reduced waste compared to traditional manufacturing methods. In some aspects, recycled and/or bio-based materials can be used in membrane fabrication by the disclosed methods. In another aspect, precise control of membrane construction with less wasted material can also reduce energy consumption during the manufacturing process. Thus, in any of these aspects, the disclosed process can be considered environmentally friendly or “green.” In one aspect, DIW membrane construction processes can generate membranes having substantially similar morphologies and separation properties compared to commercial membranes while using up to ten times less material than dip coating and similar known processes.

[0033] In one aspect, the disclosed methods allow for the creation of membranes having complex geometric designs that are not possible to construct using traditional techniques. In another aspect, the disclosed methods allow for integration of additional components including, but not limited to, sensors, catalysts, and/or bioreactors. In still another aspect, the disclosed method allow for precise control of pore size and distributions in the membranes, which can in turn lead to higher separation efficiency and improved resistance to fouling.

Method for Making an Additive Manufactured Membrane

[0034] In one aspect, disclosed herein is a method for making a membrane, the method including at least the following steps:

(a) admixing a polymer with a solvent to create an ink;

(b) printing the ink onto a substrate using an additive manufacturing method;

(c) allowing the ink to solidify into the membrane; and

(d) removing the membrane from the substrate. [0035] In an aspect, the additive manufacturing method can be direct ink writing (DIW) or another method. In a further aspect, the polymer can be polysulfone, although other polymer systems are envisioned and should also be considered disclosed, including, but not limited to, polyamide (PA), polyethylene glycol (PEG), polysulfone (PSF), polyvinylidene fluoride (PVDF), polyether sulfone (PES), polyacrylonitrile (PAN), polyimides (PI), copolyimides (including, but not limited to fluorinated (6FDA -based) copolyimides), cellulose acetate (CA), cellulose triacetate (CTA), polyethylene oxide (PEG), polytetrafluoroethylene (PTFE), polypropylene (PP), polyethylene (PE), poly(vinyl chloride) (PVC), poly(styrene-block-ethylene-block-styrene) (SES), poly(ether ether ketone) (PEEK), poly(methyl methacrylate) (PMMA), poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone) (PVP), poly(ether sulfone) (PES), poly(arylene ether sulfone) (PAES), poly(sulfone amide) (PSA), polydopamine (PDA), polybenzimidazole (PBI), polyurethane (PU), polycarbonate (PC), polyethylene terephthalate) (PET), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polyethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO- PEO), poly(glycidyl methacrylate) (PGMA), poly(dimethylsiloxane) (PDMS), poly(ethyleneimine) (PEI), poly(acrylic acid) (PAA), poly(N-isopropylacrylamide) (PNIPAM), poly(ethylene glycol) di methacrylate (PEGDMA), poly(benzimidazole) (PBI), poly(vinylidene fluoride-co- chlorotrifluoroethylene) (PVDF-CTFE), poly(arylene ether ketone) (PAEK), poly(sulfone sulfide) (PSS), poly(phenylene sulfide) (PPS), poly(arylene ether nitrile) (PAEN), poly(etherimide) (PEI), poly(phenylsulfone) (PPSU), poly(ethylene chlorotrifluoroethylene) (ECTFE), poly(aryl ether sulfone ketone) (PESK), poly(phenylene oxide) (PPG), poly(ethylene-co-vinyl alcohol) (EVOH), poly(ethylene terephthalate glycol) (PETG), poly(ethylene oxide)-poly(butylene oxide)- poly(ethylene oxide) (PEO-PBO-PEO), poly(ethylene oxide)-poly(propylene oxide) (PEO-PPO), poly(2,6-dimethyl-1 ,4-phenylene oxide) (PPG), polyvinyl alcohol-co-ethylene (PVA-co-PE), poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE), poly(vinylidene fluoride-co- chlorotrifluoroethylene-co-ethylene) (PVDF-CTFE-co-PE), poly(acrylonitrile-co-methyl methacrylate) (PAN-co-MMA), poly(acrylonitrile-co-acrylic acid) (PAN-co-AA), poly(acrylonitrile- co-itaconic acid) (PAN-co-IA), poly(vinylidene fluoride-co-hexafluoropropylene-co- tetrafluoroethylene) (PVDF-HFP-TFE), poly(styrene-block-isoprene-block-styrene) (SIS), poly(ether sulfone sulfonamide) (PESSA), poly(methyl methacrylate-co-acrylic acid) (PMMA-co- AA), poly(ethylene-co-vinyl acetate) (PEVA), poly(butylene terephthalate) (PBT), poly(isobutylene) (PIB), poly(ethylene-co-butylene) (PEB), poly(ethylene-co-octene) (PEOc), poly(isoprene) (PI), poly(butadiene) (PB), poly(styrene) (PS), poly(methyl methacrylate-co- butadiene) (PMMA-co-B), poly(ethylene-co-acrylic acid) (PEAA), poly(ethylene-co-butyl acrylate) (PEBA), poly(butadiene-co-styrene) (PBS), poly(isobutylene-co-isoprene) (HR), poly(vinyl acetate) (PVAc), poly(styrene-co-acrylonitrile) (SAN), poly(styrene-co-butadiene) (SBR), poly(methyl methacrylate-co-methacrylic acid) (PMMA-co-MAA), poly(ethylene-co-methacrylic acid) (PEMAA), poly(vinylidene chloride) (PVDC), poly(vinyl alcohol-co-acetal) (PVA-co-acetal), poly(ethylene-co-vinyl acetate-co-carbon monoxide) (PEVACO), poly(ethylene-co-vinyl alcohol- co-glycidyl methacrylate) (PEVAGMA), poly(ethylene-co-vinyl alcohol-co-acrylic acid) (PEVAA), poly(butadiene-co-styrene-co-acrylonitrile) (ABS), poly(styrene-co-acrylonitrile-co-butadiene) (SAN-B), poly(styrene-co-acrylonitrile-co-methyl methacrylate) (SAN-MMA), poly(styrene-co- methyl methacrylate-co-butadiene) (SMB), poly(butadiene-co-methyl methacrylate-co-acrylic acid) (BMA), poly(isoprene-co-butadiene) (IB), poly(isoprene-co-styrene) (IS), poly(styrene-co- maleic anhydride) (SMA), poly(methyl methacrylate-co-ethylene-co-glycidyl methacrylate) (MMEA), poly(styrene-co-ethylene-co-butylene-co-styrene) (SEBS), poly(butylene-co-maleic anhydride) (BMAH), poly(ethylene-co-acrylic acid-co-ethyl acrylate) (EAA), poly(ethylene-co- methyl acrylate-co-glycidyl methacrylate) (EMAG), poly(vinyl acetate-co-ethylene) (VAE), poly(ethylene-co-vinyl acetate-co-methyl acrylate) (PEVAMA), poly(methyl methacrylate-co-butyl acrylate-co-acrylic acid) (MMBA), poly(ethylene-co-acrylic acid-co-glycidyl methacrylate) (PEAGM), phenolic resin, polyfurfuryl alcohol (PFA), polymers of intrinsic microporosity (PIMs), chitosan, PLA (poly-lactic acid), poly dimethyl siloxane (PDMS), a PDMS derivative, or any combination thereof. In an aspect, the polymer can be a glassy polymer, a rubbery polymer, or a semi-flexible polymer material. In still another aspect, the polymer can be a virgin polymer or a recycled polymer or any combination thereof.

[0036] In one aspect, the solvent can be N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), or any combination thereof. Alternative solvents are also contemplated and should be considered disclosed including, but not limited to, but not limited to dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), chloroform, acetone, ethanol, methanol, isopropanol, acetonitrile, hexane, cyclohexane, toluene, xylene, diethyl ether, dichloromethane, ethyl acetate, methyl ethyl ketone (MEK), butanol, propylene carbonate, ethylene glycol, propylene glycol, water, formic acid, acetic acid, butyl acetate, ethyl lactate, benzene, petroleum ether, 1 ,4-dioxane, cyclohexanone, pyridine, methylene chloride, isoamyl alcohol, diisopropyl ether, diethylene glycol, ethyl ether, triethylamine, hexamethylphosphoramide (HMPA), carbon tetrachloride, 1 ,2-dichloroethane, hexamethylene diisocyanate (HDI), propionic acid, butyric acid, decane, pentane, heptane, octane, decanol, dodecane, trichloroethylene, tetralin, tetrachloroethylene, 1-butanol, isobutanol, 1-pentanol, 2-pentanol, 1-hexanol, 2-hexanol, 1- octanol, 2-octanol, 1-decanol, 1-dodecanol, acetic anhydride, propionic anhydride, butyric anhydride, diethylene glycol dimethyl ether (diglyme), ethylene carbonate, glycerol, 1 -propanol, 2-propanol, 2-methyl-1 -propanol, 3-methyl-1-butanol, 1-heptanol, 1-nonanol, 1-undecanol, 1- tridecanol, 1 -tetradecanol, 1 -pentadecanol, 1-hexadecanol, 1 -octadecanol, 1-eicosanol, 1- docosanol, 1-tetracosanol, 1-hexacosanol, 1-octacosanol, 1-triacontanol, 1-dotriacontanol, 1- tetratriacontanol, 1-pentatriacontanol, 1-hexatriacontanol, 1-heptatriacontanol, 1- octatriacontanol, 1-nonatriacontanol, 1-tetracontanol, 1-hexacontanol, 1-heptacontanol, 1- octaconanol, supercritical carbon dioxide (scCO₂), ethyl lactate, limonene, terpenes (e.g., alphapinene, beta-pinene), propylene carbonate, isopropyl myristate, 2-methyltetrahydrofuran (2- meTHF), 2,2,5,5-tetramethyl-1 ,3-dioxane (TMDO), or any combination thereof. In an aspect, the solvent can be a green solvent including, but not limited to, methyl lactate, triethylphosphate, an ionic liquid, an organic carbonate, PolarClean (methyl ester of 5-(dimethylamino)-2-methyl-5-oxo- pentanoic acid), dihydrolevoglucosenone, y-valerolactone (GVL), or any combination thereof, used alone or in combination with one or more other solvents listed above. In one aspect, the solvent is chosen based on solubility parameters of the selected membrane polymer.

[0037] In an aspect, the substrate can be any substrate with a low surface roughness such as, for example, less than about 100 nm, or less than about 80 nm, or less than about 50 nm. In another aspect, the substrate can be a silicon wafer or glass. In some aspects, the substrate can be cleaned with ethanol, isopropanol, or both prior to conducting the method. Other substances useful for cleaning the substrate include, but are not limited to, acetone, methanol, hydrochloric acid (HCI), sulfuric acid (H2SO4), citric acid, phosphoric acid (H3PO4), sodium hydroxide (NaOH), potassium hydroxide (KOH), hydrogen peroxide (H₂O₂), sodium hypochlorite (NaCIO), ammonium hydroxide (NH₄OH), EDTA (ethylenediaminetetraacetic acid), SDS (sodium dodecyl sulfate), Triton X-100 (octylphenol ethoxylate), Tween (polysorbate surfactants), sodium bicarbonate (NaHCOa), sodium carbonate (Na₂CO3), sodium metasilicate, sodium tripolyphosphate, sodium hexametaphosphate, sodium percarbonate, sodium metabisulfite, sodium thiosulfate, sodium sulfite, sodium bisulfate, sodium hypophosphite, potassium permanganate (KMnC ), potassium metabisulfite, potassium carbonate, potassium bicarbonate, hydrofluoric acid (HF), nitric acid (HNO3), oxalic acid, tartaric acid, lactic acid, glacial acetic acid, formic acid, N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), hexane, toluene, sylene, diethyl ether, dichloromethane, ethyl acetate, methyl ethyl ketone (MEK), butanol, isobutanol, propanol, hexanol, decanol, tetrahydrofuran (THF), propylene glycol, glycerol, boric acid, hydrobromic acid (HBr), peracetic acid, ethylenediamine (EDA), diethylenetriamine (DETA), triethanolamine (TEA), tetramethylammonium hydroxide (TMAH), sodium hydrogensulfite, sodium persulfate, calcium chloride, calcium carbonate, magnesium sulfate, aluminum sulfate, iron sulfate, copper sulfate, zinc sulfate, borax, sodium silicate, sodium aluminate, sodium acetate, sodium nitrate, sodium sulfate, sodium chloride, potassium nitrate, potassium sulfate, potassium chloride, barium chloride, barium sulfate, silicon dioxide, silica gel, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, iron oxide, copper oxide, zinc oxide, boron nitride, sodium borohydride (NaBH₄), sodium arsenite, potassium iodide, potassium bromide, lithium hydroxide, lithium carbonate, lithium chloride, or any combination thereof.

[0038] In one aspect, printing can be conducted at from about 1 mm/s to about 100 mm/s, or about 10 mm/s to about 50 mm/s, or at about 27 mm/s. In another aspect, printing can be conducted with a line spacing of from about 0.01 mm to about 5 mm, or about 0.1 mm to about 2 mm, or from about 0.25 mm to about 1 mm, or of about 0.7 mm. In still another aspect, printing can be conducted with an applied back pressure of from about 0.1 psi to about 100 psi, or from about 1 psi to about 50 psi, or from about 10 psi to about 25 psi, or of about 15 psi. In one aspect, printing can be conducted with a needle-substrate distance of from about 0.01 mm to about 10 mm, or from about 0.1 mm to about 2 mm, or of about 0.1 mm to about 1 mm, or of about 0.15 mm. It should be understood that print parameters can vary depending on print pattern, printer model, substrate, desired characteristics of the final membrane, solvents used, polymers, and the like.

[0039] In another aspect, printing can be conducted using a flat print pattern, a tubular membrane print pattern, a hollow fiber print pattern, a spiral wound membrane print pattern, a plate and frame shaped print pattern, a capillary shaped print pattern, a disc print pattern, or rectangular print pattern. In an alternative aspect, printing can be conducted to produce a flat sheet, a tubular membrane, a hollow fiber, a spiral wound membrane, a plate and frame shape, a capillary shape, a disc shape, or any combination thereof. In still another aspect, printing can be conducted at a relative humidity of from about 20% to about 60 %, or from about 30% to about 50%, or at about 40%. In any of these aspects, printing parameters can be adjusted a little above or a little below the given values as may be required when changing solvents, polymer systems, or final membrane parameters.

[0040] In one aspect, exposure of the printed ink to ambient humidity can lead to a vapor phase inversion of the printed ink. In some aspects, the membrane can be quenched in deionized water after step (d). In any of these aspects, the method uses at least 60% less solvent than a doctor blade method for making a comparable membrane, or at least 61, 62, 63, 64, 65, 66, 67, 68, 69, or at least 70% less solvent.

[0041] In an alternative aspect, other phase inversion non-solvents are also contemplated and should be considered disclosed including, but not limited to, methanol, ethanol, isopropanol (I PA), acetone, hexane, cyclohexane, toluene, xylene, diethyl ether, chloroform, carbon tetrachloride, dichloromethane, ethyl acetate, methyl ethyl ketone (MEK), butanol, isobutanol, acetonitrile, tetrahydrofuran (THF), dioxane, acetic acid, formic acid, phosphoric acid, sulfuric acid, hydrochloric acid, sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonium hydroxide (NH₄OH), sodium bicarbonate (NaHCOs), potassium bicarbonate (KHCO3), sodium carbonate (Na₂CO3), potassium carbonate (K2CO3), sodium phosphate (Na₃PO4), potassium phosphate (K3PO4), calcium chloride (CaCI₂), magnesium chloride (MgCI₂), sodium sulfate (Na₂SO4), potassium sulfate (K₂SO4), calcium sulfate (CaSO4), magnesium sulfate (MgSO4), sodium acetate (CHsCOONa), potassium acetate (CH3COOK), sodium chloride (NaCI), potassium chloride (KCI), calcium nitrate (Ca(NO3)2), magnesium nitrate (Mg(NO3)2), sodium nitrate (NaNOs), potassium nitrate (KNO3), sodium hypochlorite (NaCIO), hydrogen peroxide (H₂O₂), sodium borohydride (NaBH₄), sodium sulfite (Na₂SC>3), potassium sulfite (K₂SOs), sodium metabisulfite (Na₂S₂0s), potassium metabisulfite (K₂S₂0s), sodium metabisulfate (Na₂S₂O?), potassium metabisulfate (K₂S₂O?), sodium thiosulfate (Na₂S20s), potassium thiosulfate (K₂S2O3), sodium silicate (Na₂SiOs), potassium silicate (K₂SiOs), sodium fluoride (NaF), potassium fluoride (KF), sodium bromide (NaBr), potassium bromide (KBr), sodium iodide (Nal), potassium iodide (KI), sodium cyanide (NaCN), potassium cyanide (KCN), sodium sulfide (Na₂S), potassium sulfide (K₂S), sodium hydrosulfide (NaHS), potassium hydrosulfide (KHS), sodium hypophosphite (NaPO₂H₂), potassium hypophosphite (KPO₂H₂), sodium hypophosphate (Na₂HPO₂), potassium hypophosphate (K₂HPO₂), sodium hypophosphite (NaH₂PO₂), potassium hypophosphite (KH₂PO₂), sodium perchlorate (NaCldi), potassium perchlorate (KCIO4), sodium chlorate (NaCIOs), potassium chlorate (KCIO3), sodium bromate (NaBrCh), potassium bromate (KBrCh), sodium iodate (NalCh), potassium iodate (KIO3), sodium carbonate peroxide (Na₂CC>3-1.5H₂O₂), potassium carbonate peroxide (K₂CC>3-1.5H₂O₂), sodium persulfate (Na₂S₂0s), potassium persulfate (K₂S₂0s), sodium bisulfite (NaHSCh), potassium bisulfite (KHSO3), sodium bisulfate (NaHSCU), potassium bisulfate (KHSO4), sodium perborate (NaBC>3'4H₂O), potassium perborate (KBO3'4H₂O), sodium pyrophosphate (Na4P2O?), potassium pyrophosphate (K4P2O7), sodium tripolyphosphate (NasPsO ), or any combination thereof. In an aspect, where a listed compound is a solid in pure form, the compound can be used as a solute in the non-solvent such as, for example, in an aqueous solution. In a further aspect, the solute can modify one or more properties of the aqueous or other solution including, but not limited to, vapor pressure, boiling point, pH, buffering capacity, reactivity, or the like.

[0042] In an aspect, the non-solvent can be a green solvent including, but not limited to, methyl lactate, triethylphosphate, an ionic liquid, an organic carbonate, PolarClean (methyl ester of 5- (dimethylamino)-2-methyl-5-oxo-pentanoic acid), dihydrolevoglucosenone, y-valerolactone (GVL), or any combination thereof, used alone or in combination with one or more other nonsolvents listed above. In one aspect, the non-solvent is chosen based on solubility parameters of the selected membrane polymer such that the non-solvent will not dissolve or damage the membrane polymer.

Membranes Made by the Disclosed Method

[0043] Also disclosed herein are membranes made by the disclosed method. In an aspect, the membrane can be a flat membrane, a shaped membrane such as, for example, a microfluidic device or component thereof, or can be hollow fibers. Combinations of the disclosed membrane shapes and types should also be considered disclosed.

[0044] In any of these aspects, the membrane is substantially defect free. In one aspect, the membrane has an average thickness of from about 100 nm to about 250 pm, or from about 1 pm to about 150 pm, or of about 120 pm. In another aspect, the membrane has a first side and a second side, wherein the first side includes a plurality of pores having an average cross sectional diameter of about 1.4 pm on the first side, and wherein the plurality of pores have an average cross sectional diameter of about 5.4 pm on the second side. Further in this aspect, the pores may not be interconnected. In one aspect, the membrane has an area of at least 40 cm². Further in this aspect, the membrane size is scalable if method of manufacturing parameters and equipment are adjusted accordingly.

[0045] In some aspects, the membranes can be cleaned following printing or at any stage during the disclosed process. Reagents useful for cleaning membranes include, but are not limited to, sodium hydroxide (NaOH), hydrochloric acid (HCI), sulfuric acid (H2SO4), citric acid, phosphoric acid (H3PO4), acetic acid, sodium hypochlorite (NaCIO), hydrogen peroxide (H2O2), ethanol, isopropyl alcohol, sodium carbonate (Na₂CC>3), sodium bicarbonate (NaHCOs), potassium hydroxide (KOH), ammonium hydroxide (NH₄OH), EDTA (ethylenediaminetetraacetic acid), SDS (sodium dodecyl sulfate), Tween (polysorbate surfactants), Triton X-100 (octylphenol ethoxylate), sodium citrate, sodium metasilicate, sodium tripolyphosphate, sodium hexametaphosphate, sodium percarbonate, sodium metabisulfite, chlorine dioxide (CIO2), oxalic acid, tartaric acid, lactic acid, glacial acetic acid, formic acid, N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), hexane, cyclohexane, toluene, xylene, diethyl ether, dichloromethane, ethyl acetate, methyl ethyl ketone (MEK), butanol, isobutanol, propanol, hexanol, decanol, tetrahydrofuran (THF), acetone, propylene glycol, glycerol, sodium hypophosphite, potassium permanganate (KMnCU), sodium borohydride (NaBH₄). hydrofluoric acid (HF), hydrobromic acid (HBr), nitric acid (HNO3), peracetic acid, ethylenediamine (EDA), diethylenetriamine (DETA), triethanolamine (TEA), tetramethylammonium hydroxide (TMAH), sodium hydrogensulfite, sodium sulfite, sodium bisulfate, sodium thiosulfate, sodium hypophosphate, sodium perborate, sodium percarbonate, sodium persulfate, potassium carbonate, potassium bicarbonate potassium metabisulfite, potassium permanganate, potassium dichromate, potassium iodide, calcium chloride, calcium carbonate, calcium hypochlorite, magnesium sulfate, magnesium chloride, magnesium hydroxide, aluminum sulfate, aluminum chloride, iron sulfate, iron chloride, copper sulfate, zinc sulfate, zinc chloride, boric acid, sodium silicate, sodium aluminate, sodium acetate, sodium nitrate, sodium sulfate, sodium chloride, potassium nitrate, potassium sulfate, potassium chloride, barium chloride, barium sulfate, and combinations thereof. In some aspects, when the pure form of said reagents is a solid, it can be a solute in aqueous or other solution used for cleaning for the purposes of adjusting pH, buffer strength, ionic strength, or any other useful property of the membrane.

Applications of the Disclosed Additive Manufactured Membranes

[0046] In one aspect, the membranes can be used in water treatment applications such as, for example, high-performance desalination, micropollutant removal, and wastewater treatment. In another aspect, the membranes can be used in energy and environmental applications such as, for example, membrane gas separation (e.g. of CO₂ from flue gas emissions or H₂ purification for fuel cell applications); in air filtration; and in energy harvesting such as, for example, from water flow or pressure gradients in microfluidic devices.

[0047] In another aspect, the membranes can be used in biomedical and healthcare applications such as, for example, in microfluidic devices for drug delivery or medical diagnostic applications, for cell culture and tissue engineering, and/or as dialysis membranes. In still another aspect, the membranes can be used for food and beverage processing and purification, for specific separation and purification tasks in chemical and pharmaceutical manufacturing, and/or in advanced materials applications. [0048] In one aspect, disclosed herein are devices including the disclosed membranes. In another aspect, the devices are or include a wastewater filtration device, a desalination membrane, a microfluidic device, a dialysis membrane, an energy harvesting device, a gas separation membrane, an air filter, or any combination thereof.

Methods Using the Disclosed Membranes

[0049] In one aspect, disclosed herein is a method for reducing an amount of a target gas from a gas stream comprising mixed gases, the method including at least the step of passing the gas stream through the membrane and collecting a retentate and a permeate. In one aspect, the target gas can be carbon dioxide. In another aspect, the retentate has reduced concentration of the target gas and the permeate has an increased concentration of the target gas, relative to the gas stream. In another aspect, the method reduces the target gas by at least about 95% in the retentate, relative to the gas stream.

[0050] Additional uses for the membranes are contemplated and should be considered disclosed including, but not limited to, reverse osmosis (RO) systems, ultrafiltration (UF) units, microfiltration (MF) systems, nanofiltration (NF) units, dialysis machines, hemodialysis filters, peritoneal dialysis systems, blood oxygenators, ventilators with HEPA filters, water purification systems, water desalination plants, wastewater treatment plants, air purifiers with membrane filters, fuel cell membranes, membrane distillation systems, gas separation membranes, oxygen concentrators, carbon dioxide scrubbers, oil-water separators, microbial fuel cells, protein concentrators, virus removal filters, bacteria removal filters, pharmaceutical filtration systems, food and beverage processing filters, dairy filtration units, brewery filtration systems, wine filtration devices, juice clarification systems, edible oil purification filters, bioreactors with membrane modules, blood plasma separation devices, serum protein concentrators, DNA purification kits, RNA isolation columns, hemofiltration systems, protein fractionation units, peptide purification columns, lipid extraction membranes, amino acid concentration devices, enzyme immobilization membranes, antibody purification columns, DNA sequencing platforms, PCR cleanup kits, ultra-pure water systems, laboratory filtration apparatus, sample preparation kits, solid-phase extraction cartridges, filtration skids for industrial applications, HVAC air filters, water softening membranes, pervaporation membranes, evaporative cooling towers, oil and gas separation membranes, chemical process filtration units, semiconductor manufacturing filters, electrodialysis systems, gasoline vapor recovery units, blood glucose sensors with membranes, air humidifiers with membrane-based humidification, vacuum pumps with membrane filters, industrial gas purification membranes, acid mine drainage treatment systems, brine concentration membranes, hydrogen purification membranes, ethanol dehydration membranes, ammonia recovery units, heavy metal removal filters, electrochemical water treatment cells, fish farming water treatment units, pulp and paper industry filters, textile wastewater treatment membranes, landfill leachate treatment systems, electroplating wastewater treatment units, coal mine drainage filtration devices, dairy whey concentration membranes, fermentation broth clarification filters, municipal water treatment membranes, portable water purifiers with membranes, swimming pool filtration systems, aquarium water treatment units, oil spill cleanup membranes, marine ballast water treatment systems, airborne particulate matter filters, dust collection systems with membranes, water recycling membranes, desiccant dehumidifiers with membranes, geothermal brine treatment membranes, dairy processing whey filtration units, fruit juice concentration membranes, industrial wastewater reclamation systems, seawater reverse osmosis desalination plants, biogas upgrading membranes, carbon capture membranes, acid gas removal units, hydrocarbon recovery membranes, enhanced oil recovery membranes, radioactive waste treatment membranes, landfill gas purification membranes, and compressed air filtration systems with membranes.

[0051] In one aspect, disclosed herein is a method for reducing an amount of a contaminant from an aqueous solution, the method including at least the step of passing the aqueous solution through the membrane and collecting a retentate and a permeate. In one aspect, the contaminant can be a protein. In another aspect, the permeate has reduced concentration of the contaminant and the retentate has an increased concentration of the contaminant, relative to the aqueous solution. In another aspect, the method reduces the contaminant by at least about 95% in the permeate, relative to the aqueous solution.

[0052] Many modifications and other embodiments disclosed herein will come to mind to one skilled in the art to which the disclosed compositions and methods pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosures are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. The skilled artisan will recognize many variants and adaptations of the aspects described herein. These variants and adaptations are intended to be included in the teachings of this disclosure and to be encompassed by the claims herein.

[0053] Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. [0054] As will be apparent to those of skill in the art upon reading this disclosure, each of the individual embodiments described and illustrated herein has discrete components and features which may be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure.

[0055] Any recited method can be carried out in the order of events recited or in any other order that is logically possible. That is, unless otherwise expressly stated, it is in no way intended that any method or aspect set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not specifically state in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including matters of logic with respect to arrangement of steps or operational flow, plain meaning derived from grammatical organization or punctuation, or the number or type of aspects described in the specification.

[0056] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided herein can be different from the actual publication dates, which can require independent confirmation.

[0057] While aspects of the present disclosure can be described and claimed in a particular statutory class, such as the system statutory class, this is for convenience only and one of skill in the art will understand that each aspect of the present disclosure can be described and claimed in any statutory class.

[0058] It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the disclosed compositions and methods belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and relevant art and should not be interpreted in an idealized or overly formal sense unless expressly defined herein. [0059] Prior to describing the various aspects of the present disclosure, the following definitions are provided and should be used unless otherwise indicated. Additional terms may be defined elsewhere in the present disclosure.

Definitions

[0060] As used herein, “comprising” is to be interpreted as specifying the presence of the stated features, integers, steps, or components as referred to, but does not preclude the presence or addition of one or more features, integers, steps, or components, or groups thereof. Moreover, each of the terms “by”, “comprising,” “comprises”, “comprised of,” “including,” “includes,” “included,” “involving,” “involves,” “involved,” and “such as” are used in their open, non-limiting sense and may be used interchangeably. Further, the term “comprising” is intended to include examples and aspects encompassed by the terms “consisting essentially of” and “consisting of.” Similarly, the term “consisting essentially of” is intended to include examples encompassed by the term “consisting of.

[0061] As used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a polymer,” “a solvent,” or “a contaminant,” includes, but is not limited to, mixtures or combinations of two or more such polymers, solvents, or contaminants, and the like.

[0062] It should be noted that ratios, concentrations, amounts, and other numerical data can be expressed herein in a range format. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as “about” that particular value in addition to the value itself. For example, if the value “10” is disclosed, then “about 10” is also disclosed. Ranges can be expressed herein as from “about” one particular value, and/or to “about” another particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms a further aspect. For example, if the value “about 10” is disclosed, then “10” is also disclosed.

[0063] When a range is expressed, a further aspect includes from the one particular value and/or to the other particular value. For example, where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure, e.g. the phrase “x to y” includes the range from ‘x’ to ‘y’ as well as the range greater than ‘x’ and less than ‘y’. The range can also be expressed as an upper limit, e.g. 'about x, y, z, or less’ and should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘less than x’, less than y’, and ‘less than z’. Likewise, the phrase ‘about x, y, z, or greater’ should be interpreted to include the specific ranges of ‘about x’, ‘about y’, and ‘about z’ as well as the ranges of ‘greater than x’, greater than y’, and ‘greater than z’. In addition, the phrase “about ‘x’ to ‘y’”, where ‘x’ and ‘y’ are numerical values, includes “about ‘x’ to about ‘y’”.

[0064] It is to be understood that such a range format is used for convenience and brevity, and thus, should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or subranges encompassed within that range as if each numerical value and sub-range is explicitly recited. To illustrate, a numerical range of “about 0.1 % to 5%” should be interpreted to include not only the explicitly recited values of about 0.1 % to about 5%, but also include individual values (e.g., about 1%, about 2%, about 3%, and about 4%) and the sub-ranges (e.g., about 0.5% to about 1.1%; about 5% to about 2.4%; about 0.5% to about 3.2%, and about 0.5% to about 4.4%, and other possible sub-ranges) within the indicated range.

[0065] As used herein, the terms “about,” “approximate,” “at or about,” and “substantially” mean that the amount or value in question can be the exact value or a value that provides equivalent results or effects as recited in the claims or taught herein. That is, it is understood that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but may be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art such that equivalent results or effects are obtained. In some circumstances, the value that provides equivalent results or effects cannot be reasonably determined. In such cases, it is generally understood, as used herein, that “about” and “at or about” mean the nominal value indicated ±10% variation unless otherwise indicated or inferred. In general, an amount, size, formulation, parameter or other quantity or characteristic is “about,” “approximate,” or “at or about” whether or not expressly stated to be such. It is understood that where “about,” “approximate,” or “at or about” is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless specifically stated otherwise.

[0066] As used herein, the term “effective amount” refers to an amount that is sufficient to achieve the desired modification of a physical property of the composition or material. For example, an “effective amount” of a solvent refers to an amount that is sufficient to achieve the desired improvement in the property modulated by the formulation component, e.g. achieving the desired level of viscosity of polymer solution to allow the polymer to be 3D printed as an ink. The specific level in terms of vol% in a composition required as an effective amount will depend upon a variety of factors including the amount and type of polymer, relative humidity of the printing process, desired printing parameters, and end use of the membrane made using the ink. In one aspect, in the disclosed additive manufacturing process for producing a membrane, the effective amount of solvent used is substantially lower than for other methods of producing membranes such as, for example, use of a doctor blade.

[0067] As used herein, “retentate” refers to the portion of a feed fluid (liquid, vapor, or gas) that is rejected by or remains behind a membrane without passing through, while “permeate” refers to the portion of the same feed fluid that passes through the membrane. In some aspects, substances (e.g., contaminants) to be removed from a feed fluid may remain in the retentate, while substances to be concentrated (e.g., gases or value-added chemicals) may pass through the membrane and may collect in the permeate.

[0068] As used herein, the terms “optional” or “optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0069] Unless otherwise specified, temperatures referred to herein are measured at atmospheric pressure (i.e. one atmosphere).

[0070] Now having described the aspects of the present disclosure, in general, the following Examples describe some additional aspects of the present disclosure. While aspects of the present disclosure are described in connection with the following examples and the corresponding text and figures, there is no intent to limit aspects of the present disclosure to this description. On the contrary, the intent is to cover all alternatives, modifications, and equivalents included within the spirit and scope of the present disclosure.

ASPECTS

[0071] The present disclosure can be described in accordance with the following numbered aspects, which should not be confused with the claims.

[0072] Aspect 1. A method for making a membrane, the method comprising:

(a) admixing a polymer with a solvent to create an ink;

(b) printing the ink onto a substrate using an additive manufacturing method; (c) allowing the ink to solidify into the membrane; and

(d) removing the membrane from the substrate.

[0073] Aspect 2. The method of aspect 1 , wherein the additive manufacturing method comprises direct ink writing (DIW).

[0074] Aspect 3. the method of aspect 1 or 2, wherein the polymer comprises polysulfone, polyamide (PA), polyethylene glycol (PEG), polysulfone (PSF), polyvinylidene fluoride (PVDF), polyether sulfone (PES), polyacrylonitrile (PAN), polyimides (PI), copolyimides (including, but not limited to fluorinated (6FDA -based) copolyimides), cellulose acetate (CA), cellulose triacetate (CTA), polyethylene oxide (PEO), polytetrafluoroethylene (PTFE), polypropylene (PP), polyethylene (PE), poly(vinyl chloride) (PVC), poly(styrene-block-ethylene-block-styrene) (SES), poly(ether ether ketone) (PEEK), poly(methyl methacrylate) (PMMA), poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone) (PVP), poly(ether sulfone) (PES), poly(arylene ether sulfone) (PAES), poly(sulfone amide) (PSA), polydopamine (PDA), polybenzimidazole (PBI), polyurethane (PU), polycarbonate (PC), polyethylene terephthalate) (PET), poly(vinylidene fluoride-co- hexafluoropropylene) (PVDF-HFP), poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO), poly(glycidyl methacrylate) (PGMA), poly(dimethylsiloxane) (PDMS), poly(ethyleneimine) (PEI), poly(acrylic acid) (PAA), poly(N-isopropylacrylamide) (PNIPAM), polyethylene glycol) dimethacrylate (PEGDMA), poly(benzimidazole) (PBI), poly(vinylidene fluoride-co-chlorotrifluoroethylene) (PVDF-CTFE), poly(arylene ether ketone) (PAEK), poly(sulfone sulfide) (PSS), poly(phenylene sulfide) (PPS), poly(arylene ether nitrile) (PAEN), poly(etherimide) (PEI), poly(phenylsulfone) (PPSU), poly(ethylene chlorotrifluoroethylene) (ECTFE), poly(aryl ether sulfone ketone) (PESK), poly(phenylene oxide) (PPG), poly(ethylene- co-vinyl alcohol) (EVOH), polyethylene terephthalate glycol) (PETG), poly(ethylene oxide)- poly(butylene oxide)-poly(ethylene oxide) (PEO-PBO-PEO), poly(ethylene oxide)- poly(propylene oxide) (PEO-PPO), poly(2,6-dimethyl-1 ,4-phenylene oxide) (PPO), polyvinyl alcohol-co-ethylene (PVA-co-PE), poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE), poly(vinylidene fluoride-co-chlorotrifluoroethylene-co-ethylene) (PVDF-CTFE-co-PE), poly(acrylonitrile-co-methyl methacrylate) (PAN-co-MMA), poly(acrylonitrile-co-acrylic acid) (PAN-co-AA), poly(acrylonitrile-co-itaconic acid) (PAN-co-IA), poly(vinylidene fluoride-co- hexafluoropropylene-co-tetrafluoroethylene) (PVDF-HFP-TFE), poly(styrene-block-isoprene- block-styrene) (SIS), poly(ether sulfone sulfonamide) (PESSA), poly(methyl methacrylate-co- acrylic acid) (PMMA-co-AA), poly(ethylene-co-vinyl acetate) (PEVA), poly(butylene terephthalate) (PBT), poly(isobutylene) (FIB), poly(ethylene-co-butylene) (PEB), poly(ethylene-co-octene) (PEOc), poly(isoprene) (PI), poly(butadiene) (PB), poly(styrene) (PS), poly(methyl methacrylate- co-butadiene) (PMMA-co-B), poly(ethylene-co-acrylic acid) (PEAA), poly(ethylene-co-butyl acrylate) (PEBA), poly(butadiene-co-styrene) (PBS), poly(isobutylene-co-isoprene) (HR), poly(vinyl acetate) (PVAc), poly(styrene-co-acrylonitrile) (SAN), poly(styrene-co-butadiene) (SBR), poly(methyl methacrylate-co-methacrylic acid) (PMMA-co-MAA), poly(ethylene-co- methacrylic acid) (PEMAA), poly(vinylidene chloride) (PVDC), poly(vinyl alcohol-co-acetal) (PVA- co-acetal), poly(ethylene-co-vinyl acetate-co-carbon monoxide) (PEVACO), poly(ethylene-co- vinyl alcohol-co-glycidyl methacrylate) (PEVAGMA), poly(ethylene-co-vinyl alcohol-co-acrylic acid) (PEVAA), poly(butadiene-co-styrene-co-acrylonitrile) (ABS), poly(styrene-co-acrylonitrile- co-butadiene) (SAN-B), poly(styrene-co-acrylonitrile-co-methyl methacrylate) (SAN-MMA), poly(styrene-co-methyl methacrylate-co-butadiene) (SMB), poly(butadiene-co-methyl methacrylate-co-acrylic acid) (BMA), poly(isoprene-co-butadiene) (IB), poly(isoprene-co-styrene) (IS), poly(styrene-co-maleic anhydride) (SMA), poly(methyl methacrylate-co-ethylene-co-glycidyl methacrylate) (M EA), poly(styrene-co-ethylene-co-butylene-co-styrene) (SEBS), poly(butylene- co-maleic anhydride) (BMAH), poly(ethylene-co-acrylic acid-co-ethyl acrylate) (EAA), poly(ethylene-co-methyl acrylate-co-glycidyl methacrylate) (EMAG), poly(vinyl acetate-co- ethylene) (VAE), poly(ethylene-co-vinyl acetate-co-methyl acrylate) (PEVAMA), poly(methyl methacrylate-co-butyl acrylate-co-acrylic acid) (MMBA), poly(ethylene-co-acrylic acid-co-glycidyl methacrylate) (PEAGM), phenolic resin, polyfurfuryl alcohol (PFA), polymers of intrinsic microporosity (PIMs), chitosan, PLA (poly-lactic acid), poly dimethyl siloxane (PDMS), a PDMS derivative, or any combination thereof.

[0075] Aspect 4. The method of aspect 3, wherein the polymer is polysulfone.

[0076] Aspect 5. The method of any one of aspects 1-4, wherein the solvent comprises N-methy- 2-pyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), chloroform, acetone, ethanol, methanol, isopropanol, acetonitrile, hexane, cyclohexane, toluene, xylene, diethyl ether, dichloromethane, ethyl acetate, methyl ethyl ketone (MEK), butanol, propylene carbonate, ethylene glycol, propylene glycol, water, formic acid, acetic acid, butyl acetate, ethyl lactate, benzene, petroleum ether, 1 ,4-dioxane, cyclohexanone, pyridine, methylene chloride, isoamyl alcohol, diisopropyl ether, diethylene glycol, ethyl ether, or any combination thereof. [0077] Aspect 6. The method of aspect 5, wherein the solvent is N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), or any combination thereof.

[0078] Aspect 7. The method of any one of aspects 1-6, wherein the substrate comprises surface roughness of less than 100 nm.

[0079] Aspect 8. The method of aspect 7, wherein the substrate comprises a silicon wafer or glass.

[0080] Aspect 9. The method of any one of aspects 1-8, further comprising cleaning the substrate with ethanol, isopropanol, or both ethanol and isopropanol prior to conducting the method.

[0081] Aspect 10. The method of any one of aspects 1-9, wherein printing is conducted at from about 1 mm/s to about 100 mm/s.

[0082] Aspect 11 . The method of aspect 10, wherein printing is conducted at about 27 mm/s.

[0083] Aspect 12. The method of any one of aspects 1-11 , wherein printing is conducted with a line spacing of from about 0.01 mm to about 5 mm.

[0084] Aspect 13. The method of aspect 12, wherein printing is conducted with a line spacing of about 0.7 mm.

[0085] Aspect 14. The method of any one of aspects 1-13, wherein printing is conducted with an applied back pressure of from about 0.1 psi to about 100 psi.

[0086] Aspect 15. The method of aspect 14, wherein printing is conducted with an applied back pressure of about 15 psi.

[0087] Aspect 16. The method of any one of aspects 1-15, wherein printing is conducted with a needle-substrate distance of from about 0.01 mm to about 10 mm.

[0088] Aspect 17. The method of aspect 16, wherein printing is conducted with a needlesubstrate distance of about 0.15 mm.

[0089] Aspect 18. The method of any one of aspects 1-17, wherein printing is conducted using a flat print pattern, a tubular membrane print pattern, a hollow fiber print pattern, a spiral wound membrane print pattern, a plate and frame shaped print pattern, a capillary shaped print pattern, a disc print pattern, or a rectangular print pattern.

[0090] Aspect 19. The method of any one of aspects 1-18, wherein phase inversion is accomplished with a non-solvent comprising water, methanol, ethanol, isopropanol (IPA), acetone, hexane, cyclohexane, toluene, xylene, diethyl ether, chloroform, carbon tetrachloride, dichloromethane, ethyl acetate, methyl ethyl ketone (MEK), butanol, isobutanol, acetonitrile, tetrahydrofuran (THF), dioxane, acetic acid, or any combination thereof.

[0091] Aspect 20. The method of aspect 19, wherein the non-solvent is water.

[0092] Aspect 21. The method of any one of aspects 1-20, wherein printing is conducted at a relative humidity of from about 20% to about 60%.

[0093] Aspect 22. The method of aspect 21, wherein printing is conducted at a relative humidity of about 40%.

[0094] Aspect 23. The method of any one of aspects 1-22, wherein exposure of the printed ink to ambient humidity causes a vapor phase inversion of the printed ink.

[0095] Aspect 24. The method of any one of aspects 1-23, further comprising quenching the membrane in deionized water after step (d).

[0096] Aspect 25. The method of any one of aspects 1-24, wherein the method uses at least 60% less solvent than a doctor blade method for making a membrane.

[0097] Aspect 26. A membrane made by the method of any one of aspects 1-25.

[0098] Aspect 27. The membrane of aspect 26, wherein the membrane comprises a flat membrane, a shaped membrane, hollow fibers, or any combination thereof.

[0099] Aspect 28. The membrane of aspect 26 or 27, wherein the membrane is substantially defect free.

[0100] Aspect 29. The membrane of any one of aspects 26-28, wherein the membrane has an average thickness of from about 100 nm to about 250 pm.

[0101] Aspect 30. The membrane of aspect 29, wherein the membrane has an average thickness of about 120 pm.

[0102] Aspect 31. The membrane of any one of aspects 26-30, wherein the membrane comprises a first side and a second side, wherein the first side comprises a plurality of pores having an average cross sectional diameter of about 1.4 pm on the first side, and wherein the plurality of pores have an average cross sectional diameter of about 5.4 pm on the second side.

[0103] Aspect 32. The membrane of aspect 31 , wherein the pores are not interconnected. [0104] Aspect 33. The membrane of any one of aspects 26-32, wherein the membrane is at least

40 cm2.

[0105] Aspect 34. A device incorporating the membrane of any one of aspects 26-33.

[0106] Aspect 35. The device of aspect 34, wherein the device comprises a wastewater filtration device, a desalination membrane, a microfluidic device, a dialysis membrane, an energy harvesting device, a gas separation membrane, an air filter, or any combination thereof.

[0107] Aspect 36. A method for reducing an amount of a target gas from a gas stream comprising mixed gases, the method comprising passing the gas stream through the membrane of any one of aspects 26-33 and collecting a retentate and a permeate.

[0108] Aspect 37. The method of aspect 36, wherein the target gas comprises carbon dioxide.

[0109] Aspect 38. The method of aspect 36 or 37, wherein the retentate has reduced concentration of the target gas and the permeate has an increased concentration of the target gas relative to the gas stream.

[0110] Aspect 39. The method of any one of aspects 36-38, wherein the method reduces the target gas by at least about 95% in the retentate relative to the gas stream.

[0111] Aspect 40. A method for reducing an amount of a contaminant from an aqueous solution, the method comprising passing the aqueous solution through the membrane of any one of aspects 26-33 and collecting a retentate and a permeate.

[0112] Aspect 41 . The method of aspect 40, wherein the contaminant comprises a protein.

[0113] Aspect 42. The method of aspect 40 or 41 , wherein the permeate has reduced concentration of the contaminant and the retentate has an increased concentration of the contaminant relative to the aqueous solution.

[0114] Aspect 43. The method of any one of aspects 40-42, wherein the method reduces the contaminant by at least about 95% in the permeate relative to the aqueous solution.

EXAMPLES

[0115] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices and/or methods claimed herein are made and evaluated, and are intended to be purely exemplary of the disclosure and are not intended to limit the scope of what the inventors regard as their disclosure. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C or is at ambient temperature, and pressure is at or near atmospheric.

Example 1 : Materials and Experimental Methods

Materials

[0116] Polysulfone pellets (MW= 35 kDa) and dimethylacetamide (DMAc) (Sure/SealTM, 99.8% purity) were purchased from Sigma Aldrich. N-methyl-2-pyrrolidone (NMP) (ACS, VWR Chemicals BDH Sure/SealTM 99.5% purity) was purchased from VWR. The hexane (ACS purity >95%) and methanol (ACS purity >95%) utilized in the solvent exchange were purchased from VWR in individual 20 L drums. Bovine serum albumin (MW = 66kDa) was purchased from VWR. An ultra-flat silicon wafer (6” diameter, single side polish) was purchased from Ted Pella (Reading, CA, USA). Glove bags (Model Number 690323) for humidity control and temperature and humidity controllers were purchased from VWR. Ethanol (ACS purity >95%) and isopropanol (ACS purity 95%), used for cleaning purposes, were purchased from Fisher Scientific. Grade I deionized (DI) water with resistivity of 18.2 mO cm at 25 °C was used for membrane sample storage.

Formulation of Membrane Dope Solution for DIW and Doctor Blade

[0117] PSf pellets were first dried at 110°C for 24 hours under vacuum. The dried PSf was added to DMAc at a concentration of 17wt% and mixed at 230 RPM for 72 hours at 65 °C (FIG. 1A). The PSf-DMAc solution was then allowed to cool prior to use. Similarly, dope solutions used for the doctor blading method were prepared at a concentration of 17 wt.% PSf with NMP as the solvent; the solutions were mixed for 72 hours at 230 RPM and 40 °C before being cooled for use. Prior work on doctor blading by Escobar et al., was done with NMP as the solvent and it was decided to adopt it in this work as well. As noted below, no significant differences between the DIW and doctor bladed films were observed, even with different solvent usage.

Polysulfone DIW Membrane Making

[0118] For membrane fabrication, the prepared PSf-DMAc solution was pipetted into a 5-cc syringe barrel fitted with a Nordson luer-lock needle (Nordson EFD Precision Tips, Westlake, Ohio, USA) with an inner diameter of 200 pm and a length of 6.35 mm. The filled syringe was then loaded into the holder arm of a Nordson Janome JR 2304N Robotic Printer (Chicago, Illinois, USA) (FIG. 1B). Nordson EFD pressure controllers (Westlake, Ohio, USA) were used to set the pneumatic back pressure applied during printing. An ultra-flat silicon wafer was used as the printing substrate (cleaned with ethanol and isopropanol prior to use), with the separation distance between the needle and substrate set optically using a Dinocam digital microscope prior to the start of the printing process. Optimized printing parameters are presented in Table 1. A schematic of the needle path used during membrane printing is provided in FIG. 8.

[0119] The ambient relative humidity (RH) of the membrane fabrication environment was controlled by constructing a cover composed of two glove bags that fully encapsulated the 3D printer (FIG. 9). Humidified air from a mister (Ultrasonic humidifier, Guandong, China) was used to set the desired humidity level within the enclosure and the humidity level was monitored using a benchtop meter (Digital Humidity Temperature/Dew Point Meter VWR, Radnor, PA, USA). The temperature inside the enclosure was similarly monitored.

[0120] Since the printing process is typically slow, the ambient humidity causes the phase inversion to be initiated before the film is immersed in the quench bath. This was apparent in the film losing some of its optical transparency as compared to the just-printed film (FIGs. 2A-2B).

[0121] To ensure film uniformity and reproducibility, the films were allowed to undergo a full vapor phase inversion in the ambient humidity prior to quench bath submersion. DI water at ambient temperature was used for the quenching step. The fabricated membranes were kept immersed in DI water, with the water exchanged several times during the initial 24-hour period prior to testing. These exchanges were done three times on the day of fabrication and three additional times the following day.

Polysulfone Doctor Blade Membrane Making

[0122] The procedure used to fabricate polysulfone membrane sheets via doctor blading was adapted from previous studies. These membranes were fabricated at the University of Kentucky, with all subsequent characterizations done at West Virginia University. Briefly for each sample, approximately 3-5 mL of dope solution (3 mL generates a 13 * 7 cm membrane size and was the dimension used in solvent reduction analysis for this work) was poured onto a glass plate (Gardner Glass Products, North Wilkesboro, NO, USA) and cast across the surface using a doctor blade (Micrometer Adjustable Film Applicator - 250 mm, MTI Corp, Richmond, CA, USA). This casting process was performed using an automatic bench-top flat sheet casting machine (Model: BTFS-TC, PMI, Ithaca, NY USA) set at a casting speed of 500 cm/min. An automated doctor blading setup was used to avoid variations in membrane film thickness that could be present in manual casting. To match the approximate duration of the DIW process, the film was exposed to ambient air for 8 minutes (Relative humidity: 40 ± 2%) before being immersed in a water quench bath. Once immersed in the quench bath for 1 minute, the samples were stored in DI water.

Membrane Permeance Testing Protocol

[0123] All fabricated membranes underwent a compaction step with pure DI water utilizing a CF 042 standard lab grade cross flow system (Sterlitech, Kent, Washington, USA) with a membrane surface area of 42 cm² (FIG. 3). A positive displacement pump 114 was used to feed water from the feed tank 118 (~19 L) to the membrane cell 108. A bypass needle valve 116 was utilized to recycle part of the feed stream back to the feed tank 118. Chiller 100 was used to maintain temperature in the feed tank as necessary. Flowmeter 102 regulated flow of retentate 106 through back pressure regulator 104 and back into feed tank 118. Pump 114 flowed feed stream 112 through membrane cell 108 with permeate 110 leaving the membrane cell 108 after contacting the membrane.

[0124] A Polyscience chiller (Niles, IL, USA) was utilized to maintain the desired water temperature during the testing process. Transmembrane pressure across the membrane module was controlled by adjusting the control valve connected to the retentate site as well as the bypass needle valve connected to the feed site. The pressure was monitored using a pressure gauge. The retentate flow rate was monitored using a Site Read Panel Mount Flowmeter (Tampa, FL, USA). All pure water tests were carried out at a temperature of 25 °C, a 0.8 Umin retentate rate, and a 5-bar transmembrane pressure. The permeate flux was measured gravimetrically by weighing the volume of water collected over a 5-minute period. The permeate was recycled back to the feed tank, except during sample collection periods, to avoid concentration polarization. The BSA rejection tests were started once the membrane reached its steady state pure water permeance value (typically ~6 LMH/bar). Once this steady state was reached, the cross flow filtration was stopped, and all DI water was removed and replaced with 50 mg/L BSA solution. The BSA filtration experiments were performed using a retentate flow rate of 2 L/min. This increase in tangential flow was done to minimize concentration polarization. Once the filtration was restarted, an immediate sample was taken followed by three (3) more samples taken on the hour. The BSA solution permeance was measured in the same way as the pure water permeance. The feed tank and the remaining system was cleaned in between consecutive experiments to prevent membrane fouling. Membrane permeance (reported in _h ^L ) was measured using the following relation (Eq.1)

„ flux volumetric flow rate

Permeance = - pressure dif -f -erential = - ( -membrane area -) - x(pressure dif -f -erential) (1 )

BSA Rejection Measurements

[0125] UV -Visible spectrometry (UV-VIS Genesys 10-S Thermo Electron Corporation, Madison, Wl, USA) was used to quantify BSA concentrations in the feed (C_f), retentate (C_r) and permeate (C_p) solutions. The BSA concentration was determined using the absorbance at a wavelength of 280 nm. A BSA solution standard was created and utilized for all BSA rejection experiments. The resulting figure, with a regression coefficient of 0.998, can be found in FIG. 10. Membrane rejection (%R) was calculated using Eq. 2.

Scanning Electron Microscopy (SEM) Sample Preparation

[0126] All membrane films were prepared for SEM imaging (JSM-7600F, JEOL, Tokyo, Japan) by fracturing under liquid nitrogen to help preserve the internal morphology. The membrane sections were then sputter coated for 30 sec in a Cressington Sputter Coater (Argon environment) using a mixed Au/Pd metal target (60/40 ratio, Ted Pella, Watford, UK) and a sputter gas chamber pressure of ~0.1 mbar. An acceleration voltage of 5 kV and a working distance of approximately 15 mm was used.

Substrate Surface Roughness Measurement

[0127] The surface roughness of the silicon and glass substrates were determined using optical profilometry (Contour GT KO Optical Profiler, Bruker, Billerica, MA, USA). The profilometer was operated in the vertical scanning interferometry (VSI) measurement mode with a green light source for the measurement of rough surfaces, while the phase shift interferometry (PSI) measurement mode with a white light source was used for significantly smoother surface. Example 2: Results and Discussion

[0128] Prior studies have primarily focused on fabricating membranes suitable for dead-end filtration setups (< 15 cm²) and membrane spacers. In contrast, the goal of this work was to produce defect-free polysulfone membrane samples of >40 cm² area so they can be tested in labscale cross flow setups for prolonged periods.

Preliminary Optimizations

[0129] Substrate surface roughness effects. An often-overlooked aspect of membrane casting is the role of the underlying substrate which is typically a glass slide in most cases. For fabrication membranes using DIW, the surface roughness of the substrate was found to play a significant role. The glass surface did allow for some membranes to be fabricated, however, the frequency and area of defects (i.e. , holes and gaps in the printed films) produced in most of the prints did not allow for consistent and reproducible membrane fabrication. Upon focusing on the defects, it was observed that defect occurrence appeared with a certain degree of spatial consistency, which was correlated to surface roughness of the underlying substrate (FIG. 4).

[0130] The surface roughness hypothesis was further confirmed by briefly sanding the glass slide which led to a lower overall surface roughness (FIG. 4). This resulted in some defects disappearing as well as an increase in the frequency of fabricating defect free membranes. Despite these initially promising results, consistent fabrication of membranes on the glass substrate still proved challenging, leading to the use of an ultrasmooth, polished silicon wafer, with roughness measuring in the nanometer range. The frequency of defect formation was drastically reduced for the silicon wafer, compared to the glass slide (with and without sanding). The results agree with the hypothesis regarding the substrate surface roughness affecting the film formation, since the mean surface roughness of the silicon wafer was ~ 2 orders of magnitude lower than that of glass slide. All subsequent experiments were performed with the silicon wafer as the substrate. It must be noted that such subtle effects may not have been apparent if smaller dead-end filtration samples were printed instead, which highlights the need to fabricate samples of reasonable dimensions while developing new manufacturing strategies.

[0131] Relative humidity effects. The ambient relative humidity is another important factor, which plays an important role in the phase inversion process. Since water acts as a non-solvent, the amount of moisture present in the ambient air could impact the phase separation behavior of the polymer membrane. Some preliminary assessments of the relative humidity effects revealed that 40% RH provided optimum permeances for the DIW membranes. Initial pure water permeances of DIW membranes, as a function of the relative humidity, can be found in FIG. 11. The RH level, the DIW membranes were fabricated in, had a dramatic effect on the substructure morphology of the membranes. As seen in FIG. 12, a 20% RH environment produces finger like pore structure while 40% RH and above produces a honeycomb like pore structure (FIG. 5). The 20% RH membrane was fabricated and then almost instantaneously introduced into a DI water quench bath post-fabrication to begin the non-solvent induced phase separation (NIPS) process. The DIW membrane took ~ 8 mins to be printed. In the case of the 40% RH membrane, the exposure to humidity during this long print time inadvertently initiated some vapor-induced phase separation (VIPS). Partial phase inversion, as shown in FIG. 2A, could lead to non-repeatability in the membrane performance, therefore it was decided to wait for this process to be complete for all membranes. To allow for the phase inversion process to be completed, an additional ~0.5-2 mins were required and during this time, the 40% RH DIW membranes were left in the humidified glove bag. The fabrication time for doctor blade membranes was significantly shorter (3-5 seconds). To ensure a fair comparison, these membranes were also left exposed to the humid environment for 8 minutes to initiate the VIPS process in them. The honeycomb structure has been previously observed for membrane fabricated using high humidity conditions using the VIPS process. This was also seen for the doctor bladed membranes, when fabricated under equivalent RH conditions. It should be noted that typically the finger like pores generate a larger pure water flux, but in this instance, it was found to be the opposite. This is presumably because the fabrication process is a combination of partial VIPS and NIPS and hence some properties are unique to this case. Changes to printing parameters like higher print speeds and nozzles with larger diameters could reduce the printing time which will essentially eliminate the VI PS-like effects.

[0132] As noted in prior studies, the honeycomb structure has been commonly observed for a membrane fabricated using high humidity conditions using the VIPS process. This was also seen for the doctor bladed membranes, when fabricated under equivalent RH conditions. It should be noted that typically the finger like pores generate a larger pure water permeance, but in this instance, it was found to be the opposite. This is presumably because the fabrication process is a combination of partial VIPS and NIPS and hence some properties are unique to this case. Changes to printing parameters like higher print speeds and nozzles with larger diameters could reduce the printing time which will essentially eliminate the VI PS-like effects.

Morphology of DIW and Doctor Bladed Membranes [0133] Defect-free polysulfone membranes were fabricated on silicon wafers at 40% RH conditions. The performance and morphologies of these membranes were compared against doctor bladed membranes fabricated under similar conditions. To investigate the morphologies of doctor bladed and DIW membranes, SEM imaging of the surface and cross section of the membranes were performed both before and after pure water permeance testing (FIG. 5).

[0134] Owing to differences in lab safety regulations between the two universities, the chosen solvents used in doctor bladed and DIW membrane fabrication were NMP and DMAc, respectively. This solvent difference, having been explored in literature, has been noted to result in nearly identical membranes, with DMAc based membranes having slightly greater porosity compared to NMP, and thus a slightly higher pure water flux. This was found to not be the case for this study, as the NMP doctor bladed membranes exhibited a slightly higher pure water flux compared to the DIW DMAc membranes. However, this difference was deemed to not impede the comparison of fabrication methods. Here the cross-section images are almost identical, with the doctor bladed membrane having a slightly thicker selective layer than the DIW printed membranes. Both membranes had similar thickness values (-120 pm) as well. The cross-sections of both the membranes were quite symmetric as opposed to typical NIPS membranes, and this can again be attributed to the slightly long exposure to 40% RH conditions. Such symmetric morphologies have been observed for membranes prepared under high RH values. As shown in FIGs. 17A-18, the performance and morphology of DIW membranes fabricated with NMP showed minimal differences with the ones fabricated with DMAc. The morphology, as shown in FIG. 18, was not exactly similar to DMAc-membranes, however, honeycomb-like pores were observed in this case as well. The starting fluxes were significantly higher for the NMP-fabricated membranes; however, the final steady state values leveled out at similar values as DMAc-fabricated membranes. Thus this data shows that the solvent effect, while not negligible, is not particularly significant either.

[0135] SEM images were taken before and after testing (FIG. 18), and the cross-section of the DIW membrane remained unchanged in terms of thickness and porosity. However, an interesting observation was made for the doctor bladed membrane with regards to the formation of microvoids after testing. SEM imaging confirmed that this observation was indeed true, and that these voids were not simply a result of sample preparation artifacts. The microvoids are hypothesized to be due the motion of the doctor blade over the stationary glass support, which may lead to some air being trapped between the substrate and the dope during casting. It is not entirely clear as to why such microvoids are apparent on the tested samples, however, a more detailed analysis will be pursued in future. The average pore size of the membrane cross section was ~5.4 pm for DIW membranes and ~6.4 pm for doctor bladed membranes.

[0136] The cross-section images of the membranes fabricated using the two manufacturing processes are almost identical, with the doctor bladed membrane having a slightly thicker selective layer than the DIW printed membranes. Both membranes had similar thickness values (~ 120 pm) as well. The cross-sections of both the membranes were quite symmetric as opposed to typical NIPS membranes, and this can again be attributed to the slightly long exposure to 40% RH conditions. Such symmetric morphologies have been observed for membranes prepared under high RH values. SEM images were taken before and after testing, with the cross-section of both membranes remaining unchanged in terms of thickness and porosity. An interesting observation was made for the doctor bladed membrane with regards to the formation of microvoids. Multiple SEM images were taken to confirm that this observation was indeed true, and that these voids were not simply a result of sample preparation artifacts (FIG. 13). The microvoids are hypothesized to be due the motion of the doctor blade over the stationary glass support, which may lead to some air being trapped between the substrate and the dope during casting. An analysis of the size distribution of the pores in the cross-sectional SEM images as well as the corresponding BET data can be found in FIGs. 14A-15. The average pore size of the membrane cross section was ~5.4 pm for DIW membranes and ~6.4 pm for doctor bladed membranes. For this range of pore-sizes (i.e. >300 nm), the BET analysis was not particularly useful and no changes were apparent in the pore size distribution of just-prepared and tested membranes.

[0137] Unlike the cross section, few key differences were observed between the two membrane types in terms of the surface SEM images. Interestingly, the side that is open to the atmosphere has larger pores (~3.4 pm), compared to the side fabricated on the printing substrate (~1.4 pm). In contrast, the selective layer of the doctor bladed membrane was formed at the surface facing the atmosphere, with pores of ~1.7 pm. It is the difference in printing substrates (ultra-smooth silicon wafer as opposed to a glass slide) that influences the selective layer formation. When membranes were manufactured on the glass slide, the membrane is released off the slide surface almost instantaneously when it is quenched in water, whereas the silicon wafer fabricated membranes would release in ~45 seconds after submergence. The contrast in surface roughness (FIG. 4) between the glass slide and the silicon wafer is the hypothesized reason for the membrane sticking longer to the substrate. It is this increased membrane dwell time on the substrate that allows for a smaller pore size distribution to be formed on the bottom of the DIW membrane rather than in the middle like in most pure VIPS process. These trends can be seen in the feed and permeate pore sizes. Bearing these differences in mind, the surface with the smaller pore size was chosen as the “feed” side in both cases. Another interesting observation was the dilation of pores in both the feed and permeate sides of the DIW membrane. It is hypothesized that the diffusion of the solvent (i.e., DMAc) was incomplete and the application of transmembrane pressure caused the residual DMAc to diffuse across the membrane, therefore dilating the pores on both surfaces. In both membrane types, complete densification of the selective layer did not occur, as previously observed, due to the exposure to moisture for slightly longer time periods.

Separation Performance of DIW and Doctor Bladed Membranes

[0138] The combined VIPS and NIPS process not only influences the morphology, but also the resulting performance. A tight cross-section was formed due to slow non-solvent induced demixing kinetics, and this resulted in lower water permeances than the prior studies reported using polysulfone membranes with finger-like pores. While the cross-section was very porous, the pores lacked inter-connectivity and led to a more tortuous diffusion pathway for the water and solute molecules.

[0139] The steady state pure water permeance of the DIW membranes (120 hours) and doctor bladed membranes (80 hours) was determined in a cross flow system. (FIG. 5). Such a system allowed testing the membrane samples in presence of a tangential retentate stream which further validates their mechanical integrity under realistic conditions.

[0140] Both doctor bladed and printed membranes showed similar characteristics in their pure water permeance behavior. Despite an initial variability in starting initial pure water permeances, the final pure water permeances attained by both DIW and doctor bladed membranes were the similar (~6 LMH/bar). The doctor bladed membranes showed a slightly higher initial permeance of 110 LMH/bar compared to 96 LMH/bar for the DIW membranes. The decline in pure water permeance over time for both membrane types was a noted concern for this study. This decline was hypothesized to occur either due to membrane compaction or simply due to collapse in the porous structure during drying. To investigate the porous structure collapse phenomenon, a method, known as solvent exchange, was borrowed from hollow fiber spinning. This process involves slowly displacing the water within the pores of the membrane using volatile solvents like methanol and hexane. For each solvent the membrane is allowed to dwell for 20 minutes before the solvent is drained and replaced with fresh solvent. This was repeated 3 times for each solvent. Following the final hexane wash, the membrane was allowed to dry overnight before being dried in a vacuum oven at 75 °C for 2 hours. Once the membrane was allowed to cool it was immediately tested in the cross flow system. Unfortunately, this solvent exchange did not prevent the pure water permeance decay with the subsequent results of that experiment shown in FIG. 16. This showed that the cause of pure water permeance decline was primarily due to membrane compaction. The solvent exchange procedure was discontinued for subsequent experiments.

[0141] The two types of membranes were also compared in terms of BSA solution permeance and rejection. (FIGs. 6A-6B). Since BSA fouling was expected, a high retentate flow rate of ~ 2 L/min was used for these experiments. A decline in %rejection and BSA permeance was observed with time, despite this high retentate flow rate, and this could be attributed to fouling-induced concentration polarization. The BSA rejection was ~60-80% initially and dropped to ~30% in case of both the membranes. These values are lower than previously reported values for polysulfone membranes, the primary reason being the high (40% RH) humidity conditions used here. As noted in the context of the surface morphology, the presence of moisture prevents the complete densification of the selective layer and this affects both membranes almost equally. On the other hand, the “closed pore” structure of the cross section provides a highly tortuous diffusion pathway for the solute molecules. In this case of high solute diffusion through the selective layer, the tortuous cross section presumably contributes more to the rejection value.

[0142] The BSA water permeance was slightly higher in the DIW membranes (5.7 LMH/bar) compared to the doctor bladed membranes (4.5 LMH/bar). However, after filtering BSA solution for three (3) hours the membrane permeance had switched, with the doctor bladed membranes finishing with a higher permeance (2.3 LMH/bar) as opposed to the DIW membranes (1.7 LMH/bar). Nevertheless, it is interesting to note that no significant differences were observed in terms of the morphology and performance for the DIW membranes from the doctor bladed membranes. This is encouraging, since the DIW process required only ~37% of solvent for fabricating an equivalent size of membrane sample compared to doctor blading. In the current stage of development, the permeance and BSA rejection values are not at par with other state- of-the-art liquid separation membranes, however, several processing parameters (e.g., RH) and printing parameters (e.g., print speed, printing pattern) can be engineered to improve the separation performance. With respect to the fabrication time to create the membranes, parallelization through using multiple nozzles or nozzle arrays may help scale up the manufacturing throughput by reducing the printing time to be on the timescale of doctor blading. Employing nozzles with larger tip diameters can contribute to print time reduction by allowing for higher flowrates while the use of nozzles with unique tip geometries may provide additional dimensions for engineering the local shear flow conditions during deposition. Finally, the capacity for tuning the local flow rate of the dope solution through a combination of nozzle travel speed (print speed) and the driving pneumatic pressure may allow for locally controlling the membrane thickness, thus influencing the formation of the internal porosity across the membrane film. The large toolkit available for the DI W process provides opportunities to further engineer the structures and properties of these membranes and achieve better separation performance.

[0143] The reduction of solvent used during DIW membrane samples compared to doctor blade fabricated samples was determined from considering the dope solution volume needed for equivalent membrane areas. Using the doctor blade to fabricate a cross flow sized membrane (i.e. 13 x 7 cm polysulfone film) for use at West Virginia University required 3 ml_ of dope solution. To manufacture the same size membrane using the DIW fabrication method only requires 1.1 ml_. The percent reduction in solvent usage was calculated using the equations below 0.367 (3)

100(1 - 0.367) = 63.3% (4)

Summary and Conclusions

[0144] This work establishes direct ink writing as a novel and sustainable manufacturing technology for polysulfone membranes. When compared to doctor blading, the DIW membranes achieved virtually indistinguishable morphologies as well as similar values of steady state permeances and BSA rejections. Substrate surface roughness and ambient humidity played a significant role in regulating the morphology and performance of these membranes. Importantly, this technique only requires 37% of the solvent used per area of membrane compared to doctor blading. The DIW membranes are easy to scale and show stable performance when tested for prolonged time periods under cross flow conditions. In this work the primary focus was to develop a prototype and benchmark these membranes against doctor bladed membranes. Beyond the parameters discussed, the DIW process involves a large toolkit of tunable parameters, that can aid in advancing this technology and improving the separation performance of these membranes. It is envisioned that this technology could be transformative for scalable membrane manufacturing, especially for emerging applications. With impending regulations on the use of toxic solvents and the increasing focus on sustainable manufacturing, this DIW strategy allows for equivalent membrane area production with a fraction of material and solvent usage compared to traditional processes. [0145] While polysulfone based liquid separation membranes were the focus here, future advancements in this technology could enable non-porous membranes for gas and vapor separations. The technology is not limited to polysulfone and can be extended to other glassy and rubbery polymers used for membrane manufacturing. The technique can possibly be adapted to produce advanced configurations like hollow fibers wherein multiple parallel nozzles can be used to simultaneously extrude the “dope” and “bore” solutions. The ability to fabricate such advanced configurations will expand the applicability of this novel technology to make membranes for varied separation processes.

[0146] It should be emphasized that the above-described embodiments of the present disclosure are merely possible examples of implementations set forth for a clear understanding of the principles of the disclosure. Many variations and modifications may be made to the abovedescribed embodiment(s) without departing substantially from the spirit and principles of the disclosure. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.

REFERENCES

1. Balani, SB et al, “Processes and materials used for direct writing technologies: A review,” Results Eng., vol. 11 , p. 100257, Sep. 2021, doi: 10.1016/j.rineng.2021.100257.

2. Baldo, LGM et al, “Water vapor permeation and morphology of polysulfone membranes prepared by phase inversion,” Polimeros, vol. 30, no. 3, p. e2020027, 2020, doi: 10.1590/0104-1428.05820.

3. Cevallos-Mendoza, J et al, “Removal of Contaminants from Water by Membrane Filtration: A Review,” Membranes, vol. 12, no. 6, p. 570, May 2022, doi: 10.3390/membranes12060570.

4. Chae Park, H et al, “Membrane formation by water vapor induced phase inversion,” J. Membr. Sci., vol. 156, no. 2, pp. 169-178, Apr. 1999, doi: 10.1016/50376-7388(98)00359-7.

5. del-Mazo-Barbara, L et al, “Rheological characterisation of ceramic inks for 3D direct ink writing: A review,” J. Eur. Ceram. Soc., vol. 41 , no. 16, pp. 18-33, Dec. 2021, doi: 10.1016/j.jeurceramsoc.2021.08.031.

6. Dong, X et al, “Comparison of two low-hazard organic solvents as individual and cosolvents for the fabrication of polysulfone membranes,” AIChE J., vol. 66, no. 1 , pp. 1-14, 2020, doi: 10.1002/aic.16790. Dong, X et al, “Investigation of the Use of a Bio-Derived Solvent for Non-Solvent-lnduced Phase Separation (NIPS) Fabrication of Polysulfone Membranes,” Membranes, vol. 8, no. 2, p. 23, May 2018, doi: 10.3390/membranes8020023. Dong, X et al., “Eco-friendly solvents and their mixture for the fabrication of polysulfone ultrafiltration membranes: An investigation of doctor blade and slot die casting methods,” J. Membr. Sci., vol. 614, p. 118510, Nov. 2020, doi: 10.1016/j.memsci.2020.118510. Han, M-J et al, “Changes in morphology and transport characteristics of polysulfone membranes prepared by different demixing conditions,” J. Membr. Sci., vol. 98, no. 3, pp. 191-200, Jan. 1995, doi: 10.1016/0376-7388(94)00181-W. Imtiaz, B et al, “Direct ink writing of dehydrofluorinated Poly(Vinylidene Difluoride) for microfiltration membrane fabrication,” J. Membr. Sci., vol. 632, p. 119347, Aug. 2021 , doi: 10.1016/j.memsci.2021.119347. Khare, V et al, “Vapor-induced phase separation — effect of the humid air exposure step on membrane morphology Part I. Insights from mathematical modeling,” J. Membr. Sci., vol. 258, no. 1-2, pp. 140-156, Aug. 2005, doi: 10.1016/j.memsci.2005.03.015. Kumar, R et al, “Fouling control on microfiltration/ultrafiltration membranes: Effects of morphology, hydrophilicity, and charge,” J. Appl. Polym. Sci., vol. 132, no. 21 , p. n/a-n/a, Jun. 2015, doi: 10.1002/app.42042. Li, X et al, “3D printed robust superhydrophilic and underwater superoleophobic composite membrane for high efficient oil/water separation,” Sep. Purif. Technol., vol. 237, p. 116324, Apr. 2020, doi: 10.1016/j.seppur.2019.116324. Lin, J et al, “Thermally Stable Poly(vinylidene fluoride) for High-Performance Printable Piezoelectric Devices,” ACS Appl. Mater. Interfaces, vol. 12, no. 19, pp. 21871-21882, May 2020, doi: 10.1021/acsami.0c03675. Low, Z et al, “Perspective on 3D printing of separation membranes and comparison to related unconventional fabrication techniques,” J. Membr. Sci., vol. 523, no. May 2016, pp. 596-613, Feb. 2017, doi: 10.1016/j.memsci.2016.10.006. Lu, D et al, “Fabrication and evaporation time investigation of water treatment membranes using green solvents and recycled polyethylene terephthalate,” J. Appl. Polym. Sci., vol. 139, no. 35, Sep. 2022, doi: 10.1002/app.52823. Lv, J et al., “3D printing of a mechanically durable superhydrophobic porous membrane for oil-water separation,” J. Mater. Chem. A, vol. 5, no. 24, pp. 12435-12444, 2017, doi: 10.1039/C7TA02202F. Madaeni, SS et al, “Effect of type of solvent and non-solvents on morphology and performance of polysulfone and polyethersulfone ultrafiltration membranes for milk concentration,” Polym. Adv. Technol., vol. 16, no. 10, pp. 717-724, Oct. 2005, doi: 10.1002/pat.647. Ogbuoji, EA et al, “Non-Solvent Induced Phase Separation (NIPS) for Fabricating High Filtration Efficiency (FE) Polymeric Membranes for Face Mask and Air Filtration Applications,” Membranes, vol. 12, no. 7, p. 637, Jun. 2022, doi: 10.3390/membranes12070637. Qian, X et al, “Advancements in conventional and 3D printed feed spacers in membrane modules,” Desalination, vol. 556, p. 116518, Jun. 2023, doi: 10.1016/j. desal.2023.116518. Qian, X et al., “A critical review and commentary on recent progress of additive manufacturing and its impact on membrane technology,” J. Membr. Sci., vol. 645, p. 120041 , Mar. 2022, doi: 10.1016/j. memsci.2021.120041. Saadi, MaSR et al., “Direct Ink Writing: A 3D Printing Technology for Diverse Materials,” Adv. Mater., vol. 34, no. 28, p. 2108855, 2022, doi: 10.1002/adma.202108855. Sablani, S et al, “Concentration polarization in ultrafiltration and reverse osmosis: a critical review,” Desalination, vol. 141 , no. 3, pp. 269-289, Dec. 2001 , doi: 10.1016/S0011- 9164(01)85005-0. Saljoughi, E et al, “Preparation and characterization of novel polysulfone nanofiltration membranes for removal of cadmium from contaminated water,” Sep. Purif. Technol., vol. 90, pp. 22-30, Apr. 2012, doi: 10.1016/j.seppur.2012.02.008. Sanyal, O et al, “Design of ultrathin nanostructured polyelectrolyte-based membranes with high perchlorate rejection and high permeability,” Sep. Purif. Technol., vol. 145, pp. 113-119, May 2015, doi: 10.1016/j.seppur.2015.03.011. Sanyal, O et al., “Cause and effects of hyperskin features on carbon molecular sieve (CMS) membranes,” J. Membr. Sci., vol. 551 , pp. 113-122, Apr. 2018, doi:

10.1016/j. memsci.2018.01.021. Su, YS et al., “Interplay of mass transfer, phase separation, and membrane morphology in vapor-induced phase separation,” J. Membr. Sci., vol. 338, no. 1-2, pp. 17-28, Aug. 2009, doi: 10.1016/j.memsci.2009.03.050. Thiam, BG et al, “3D Printed and Conventional Membranes — A Review,” Polymers, vol. 14, no. 5, p. 1023, Mar. 2022, doi: 10.3390/polym14051023. Wang, D et al, “Preparation and characterization of high-flux polysulfone hollow fibre gas separation membranes,” J. Membr. Sci., vol. 204, no. 1-2, pp. 247-256, Jul. 2002, doi: 10.1016/S0376-7388(02)00047-9. Xu, Z et al, “Antifouling polysulfone ultrafiltration membranes with pendent sulfonamide groups,” J. Membr. Sci., vol. 548, pp. 481-489, Feb. 2018, doi: 10.1016/j.memsci.2017.11.064. Yanar, N et al, “Toward greener membranes with 3D printing technology,” Environ. Eng. Res., vol. 26, no. 2, pp. 200027-0, Apr. 2020, doi: 10.4491/eer.2020.027. Yuan, S et al., “Structure architecture of micro/nanoscale ZIF-L on a 3D printed membrane for a superhydrophobic and underwater superoleophobic surface,” J. Mater. Chem. A, vol. 7, no. 6, pp. 2723-2729, 2019, doi: 10.1039/C8TA10249J.

Claims

CLAIMS What is claimed is:

1. A method for making a membrane, the method comprising:

(a) admixing a polymer with a solvent to create an ink;

(b) printing the ink onto a substrate using an additive manufacturing method;

(c) allowing the ink to solidify into the membrane; and

(d) removing the membrane from the substrate.

2. The method of claim 1 , wherein the additive manufacturing method comprises direct ink writing (DIW).

3. The method of claim 1 , wherein the polymer comprises polysulfone, polyamide (PA), polyethylene glycol (PEG), polysulfone (PSF), polyvinylidene fluoride (PVDF), polyether sulfone (PES), polyacrylonitrile (PAN), polyimides (PI), copolyimides (including, but not limited to fluorinated (6FDA -based) copolyimides), cellulose acetate (CA), cellulose triacetate (CTA), polyethylene oxide (PEO), polytetrafluoroethylene (PTFE), polypropylene (PP), polyethylene (PE), poly(vinyl chloride) (PVC), poly(styrene-block-ethylene-block-styrene) (SES), poly(ether ether ketone) (PEEK), poly(methyl methacrylate) (PMMA), poly(vinyl alcohol) (PVA), poly(vinyl pyrrolidone) (PVP), poly(ether sulfone) (PES), poly(arylene ether sulfone) (PAES), poly(sulfone amide) (PSA), polydopamine (PDA), polybenzimidazole (PBI), polyurethane (PU), polycarbonate (PC), polyethylene terephthalate) (PET), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO- PEO), poly(glycidyl methacrylate) (PGMA), poly(dimethylsiloxane) (PDMS), poly(ethyleneimine) (PEI), poly(acrylic acid) (PAA), poly(N-isopropylacrylamide) (PNIPAM), polyethylene glycol) di methacrylate (PEGDMA), poly(benzimidazole) (PBI), poly(vinylidene fluoride-co- chlorotrifluoroethylene) (PVDF-CTFE), poly(arylene ether ketone) (PAEK), poly(sulfone sulfide) (PSS), poly(phenylene sulfide) (PPS), poly(arylene ether nitrile) (PAEN), poly(etherimide) (PEI), poly(phenylsulfone) (PPSU), polyethylene chlorotrifluoroethylene) (ECTFE), poly(aryl ether sulfone ketone) (PESK), poly(phenylene oxide) (PPG), poly(ethylene-co-vinyl alcohol) (EVOH), poly(ethylene terephthalate glycol) (PETG), poly(ethylene oxide)-poly(butylene oxide)- poly(ethylene oxide) (PEO-PBO-PEO), poly(ethylene oxide)-poly(propylene oxide) (PEO-PPO), poly(2,6-dimethyl-1 ,4-phenylene oxide) (PPG), polyvinyl alcohol-co-ethylene (PVA-co-PE), poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE), poly(vinylidene fluoride-co- chlorotrifluoroethylene-co-ethylene) (PVDF-CTFE-co-PE), poly(acrylonitrile-co-methyl methacrylate) (PAN-co-MMA), poly(acrylonitrile-co-acrylic acid) (PAN-co-AA), poly(acrylonitrile- co-itaconic acid) (PAN-co-IA), poly(vinylidene fluoride-co-hexafluoropropylene-co- tetrafluoroethylene) (PVDF-HFP-TFE), poly(styrene-block-isoprene-block-styrene) (SIS), poly(ether sulfone sulfonamide) (PESSA), poly(methyl methacrylate-co-acrylic acid) (PMMA-co- AA), poly(ethylene-co-vinyl acetate) (PEVA), poly(butylene terephthalate) (PBT), poly(isobutylene) (PIB), poly(ethylene-co-butylene) (PEB), poly(ethylene-co-octene) (PEOc), poly(isoprene) (PI), poly(butadiene) (PB), poly(styrene) (PS), poly(methyl methacrylate-co- butadiene) (PMMA-co-B), poly(ethylene-co-acrylic acid) (PEAA), poly(ethylene-co-butyl acrylate) (PEBA), poly(butadiene-co-styrene) (PBS), poly(isobutylene-co-isoprene) (HR), poly(vinyl acetate) (PVAc), poly(styrene-co-acrylonitrile) (SAN), poly(styrene-co-butadiene) (SBR), poly(methyl methacrylate-co-methacrylic acid) (PMMA-co-MAA), poly(ethylene-co-methacrylic acid) (PEMAA), poly(vinylidene chloride) (PVDC), poly(vinyl alcohol-co-acetal) (PVA-co-acetal), poly(ethylene-co-vinyl acetate-co-carbon monoxide) (PEVACO), poly(ethylene-co-vinyl alcohol- co-glycidyl methacrylate) (PEVAGMA), poly(ethylene-co-vinyl alcohol-co-acrylic acid) (PEVAA), poly(butadiene-co-styrene-co-acrylonitrile) (ABS), poly(styrene-co-acrylonitrile-co-butadiene) (SAN-B), poly(styrene-co-acrylonitrile-co-methyl methacrylate) (SAN-MMA), poly(styrene-co- methyl methacrylate-co-butadiene) (SMB), poly(butadiene-co-methyl methacrylate-co-acrylic acid) (BMA), poly(isoprene-co-butadiene) (IB), poly(isoprene-co-styrene) (IS), poly(styrene-co- maleic anhydride) (SMA), poly(methyl methacrylate-co-ethylene-co-glycidyl methacrylate) (MMEA), poly(styrene-co-ethylene-co-butylene-co-styrene) (SEBS), poly(butylene-co-maleic anhydride) (BMAH), poly(ethylene-co-acrylic acid-co-ethyl acrylate) (EAA), poly(ethylene-co- methyl acrylate-co-glycidyl methacrylate) (EMAG), poly(vinyl acetate-co-ethylene) (VAE), poly(ethylene-co-vinyl acetate-co-methyl acrylate) (PEVAMA), poly(methyl methacrylate-co-butyl acrylate-co-acrylic acid) (MMBA), poly(ethylene-co-acrylic acid-co-glycidyl methacrylate) (PEAGM), phenolic resin, polyfurfuryl alcohol (PFA), polymers of intrinsic microporosity (PIMs), chitosan, PLA (poly-lactic acid), poly dimethyl siloxane (PDMS), a PDMS derivative, or any combination thereof.

4. The method of claim 3, wherein the polymer is polysulfone.

5. The method of claim 1 , wherein the solvent comprises N-methy-2-pyrrolidone (NMP), dimethylacetamide (DMAc), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), chloroform, acetone, ethanol, methanol, isopropanol, acetonitrile, hexane, cyclohexane, toluene, xylene, diethyl ether, dichloromethane, ethyl acetate, methyl ethyl ketone (MEK), butanol, propylene carbonate, ethylene glycol, propylene glycol, water, formic acid, acetic acid, butyl acetate, ethyl lactate, benzene, petroleum ether, 1 ,4-dioxane, cyclohexanone, pyridine, methylene chloride, isoamyl alcohol, diisopropyl ether, diethylene glycol, ethyl ether, or any combination thereof.

6. The method of claim 5, wherein the solvent is N-methyl-2-pyrrolidone (NMP), dimethylacetamide (DMAc), or any combination thereof.

7. The method of claim 1 , wherein the substrate comprises surface roughness of less than 100 nm.

8. The method of claim 7, wherein the substrate comprises a silicon wafer or glass.

9. The method of claim 1 , further comprising cleaning the substrate with ethanol, isopropanol, or both ethanol and isopropanol prior to conducting the method.

10. The method of claim 1 , wherein printing is conducted at from about 1 mm/s to about 100 mm/s.

11. The method of claim 10, wherein printing is conducted at about 27 mm/s.

12. The method of claim 1 , wherein printing is conducted with a line spacing of from about 0.01 mm to about 5 mm.

13. The method of claim 12, wherein printing is conducted with a line spacing of about 0.7 mm.

14. The method of claim 1 , wherein printing is conducted with an applied back pressure of from about 0.1 psi to about 100 psi.

15. The method of claim 14, wherein printing is conducted with an applied back pressure of about 15 psi.

16. The method of claim 1 , wherein printing is conducted with a needle-substrate distance of from about 0.01 mm to about 10 mm.

17. The method of claim 16, wherein printing is conducted with a needle-substrate distance of about 0.15 mm.

18. The method of claim 1 , wherein printing is conducted using a flat print pattern, a tubular membrane print pattern, a hollow fiber print pattern, a spiral wound membrane print pattern, a plate and frame shaped print pattern, a capillary shaped print pattern, a disc print pattern, or a rectangular print pattern.

19. The method of claim 1 , wherein phase inversion is accomplished with a non-solvent comprising water, methanol, ethanol, isopropanol (IPA), acetone, hexane, cyclohexane, toluene, xylene, diethyl ether, chloroform, carbon tetrachloride, dichloromethane, ethyl acetate, methyl ethyl ketone (MEK), butanol, isobutanol, acetonitrile, tetra hydrofuran (THF), dioxane, acetic acid, or any combination thereof.

20. The method of claim 19, wherein the non-solvent is water.

21. The method of claim 1 , wherein printing is conducted at a relative humidity of from about 20% to about 60%.

22. The method of claim 21, wherein printing is conducted at a relative humidity of about 40%.

23. The method of claim 1 , wherein exposure of the printed ink to ambient humidity causes a vapor phase inversion of the printed ink.

24. The method of claim 1 , further comprising quenching the membrane in deionized water after step (d).

25. The method of claim 1 , wherein the method uses at least 60% less solvent than a doctor blade method for making a membrane.

26. A membrane made by the method of any one of claims 1-25.

27. The membrane of claim 26, wherein the membrane comprises a flat membrane, a shaped membrane, hollow fibers, or any combination thereof.

28. The membrane of claim 26, wherein the membrane is substantially defect free.

29. The membrane of claim 26, wherein the membrane has an average thickness of from about 100 nm to about 250 pm.

30. The membrane of claim 29, wherein the membrane has an average thickness of about 120 pm.

31. The membrane of claim 26, wherein the membrane comprises a first side and a second side, wherein the first side comprises a plurality of pores having an average cross sectional diameter of about 1.4 pm on the first side, and wherein the plurality of pores have an average cross sectional diameter of about 5.4 pm on the second side.

32. The membrane of claim 31 , wherein the pores are not interconnected.

33. The membrane of claim 26, wherein the membrane is at least 40 cm².

34. A device incorporating the membrane of claim 26.

35. The device of claim 34, wherein the device comprises a wastewater filtration device, a desalination membrane, a microfluidic device, a dialysis membrane, an energy harvesting device, a gas separation membrane, an air filter, or any combination thereof.

36. A method for reducing an amount of a target gas from a gas stream comprising mixed gases, the method comprising passing the gas stream through the membrane of claim 26 and collecting a retentate and a permeate.

37. The method of claim 36, wherein the target gas comprises carbon dioxide.

38. The method of claim 36, wherein the retentate has reduced concentration of the target gas and the permeate has an increased concentration of the target gas relative to the gas stream.

39. The method of claim 36, wherein the method reduces the target gas by at least about 95% in the retentate relative to the gas stream.

40. A method for reducing an amount of a contaminant from an aqueous solution, the method comprising passing the aqueous solution through the membrane of claim 26 and collecting a retentate and a permeate.

41. The method of claim 40, wherein the contaminant comprises a protein.

42. The method of claim 40, wherein the permeate has reduced concentration of the contaminant and the retentate has an increased concentration of the contaminant relative to the aqueous solution.

43. The method of claim 40, wherein the method reduces the contaminant by at least about 95% in the permeate relative to the aqueous solution.