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Li L, Baig MI, de Vos WM, Lindhoud S. Biocatalytic PEI-PSS membranes through aqueous phase separation: influence of casting solution pH and operational temperature. SOFT MATTER 2024; 20:5425-5434. [PMID: 38946525 DOI: 10.1039/d4sm00311j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Biocatalytic membranes combine the separation properties of membranes and the catalytic abilities of enzymes, holding great promise for industries where both purification and conversion are required. In this work, polyelectrolyte complex membranes incorporated with lysozyme were prepared using polyethyleneimine (PEI) and poly(sodium 4-styrenesulfonate) (PSS) through a one-step and mild pH shift aqueous phase separation (APS) approach. The effects of lysozyme addition and casting solution pH on the membrane properties were studied. All the membranes, both with and without added lysozyme, exhibited asymmetric structures with relatively dense top surfaces and porous cross-sections with finger-like macrovoids. The incorporation of lysozyme did not significantly influence the structure and permeability of the formed membranes. The PEI-PSS biocatalytic membranes exhibited temperature dependent enzymatic activity. The activity strongly increased with increased operational temperature, with the highest activity of 4.30 ± 0.15 U cm-2 at 45 °C. This indicates a responsive effect, where a higher temperature leads to some swelling of the polyelectrolyte complex membrane, making the enzyme more accessible to the used substrate. Moreover, the biocatalytic membranes demonstrate desirable enzymatic stability, maintaining 60% activity even after 60 days of storage. This study validates the potential of the water-based APS process as a straightforward approach for integrating enzymes into responsive biocatalytic membranes.
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Affiliation(s)
- Lijie Li
- Faculty of Science and Technology, Department of Molecules & Materials, MESA+ Institute for Nanotechnology, University of Twente, Enschede 7500 AE, The Netherlands.
- Department of Membrane Science and Technology, MESA+ Institute for Nanotechnology, University of Twente, Enschede 7500 AE, The Netherlands
| | - Muhammad Irshad Baig
- Department of Membrane Science and Technology, MESA+ Institute for Nanotechnology, University of Twente, Enschede 7500 AE, The Netherlands
| | - Wiebe M de Vos
- Department of Membrane Science and Technology, MESA+ Institute for Nanotechnology, University of Twente, Enschede 7500 AE, The Netherlands
| | - Saskia Lindhoud
- Faculty of Science and Technology, Department of Molecules & Materials, MESA+ Institute for Nanotechnology, University of Twente, Enschede 7500 AE, The Netherlands.
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2
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Li J, de Heer Kloots MHP, van Ewijk G, van Dijken DJ, de Vos WM, van der Gucht J. Evaporation-Induced Polyelectrolyte Complexation: The Role of Base Volatility and Cosolvents. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:2531-2542. [PMID: 38258284 PMCID: PMC10851664 DOI: 10.1021/acs.langmuir.3c02656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 01/10/2024] [Accepted: 01/11/2024] [Indexed: 01/24/2024]
Abstract
Film formation is a vital step for coating applications where a homogeneous, defect-free solid phase should be obtained, starting from a liquid casting formulation. Recently, an alternative waterborne-coating approach was proposed, based on the formation of a polyelectrolyte complex film. In this approach, an evaporating base induces a pH change during drying that initiates the complexation of oppositely charged polyelectrolytes, followed by further densification. In previous studies, ammonia was used as the evaporative base, leading to relatively fast evaporation and resulting in films showing significant brittleness, which tended to crack at low relative humidity or larger thicknesses. We hypothesize that slower complexation and/or evaporation can reduce the problematic stress build-up in the prepared polyelectrolyte complex coatings. For this reason, we studied the changes in the film formation process when there are different bases and cosolvents. We found that reducing the evaporation rate by changing ammonia to the slower evaporating dimethylamine or by adding DMSO as a cosolvent, led to less internal stress build-up during film formation, which could be beneficial for film application. Indeed, films prepared with ammonia showed cracking after 1 h, while films prepared with dimethylamine only showed cracking after one month. The fast evaporation of ammonia was also found to cause a temporary turbid phase, indicating phase separation, while for the slower evaporating bases, this did not occur. All prepared films remained sensitive to humidity, which poses the next challenge for these promising coatings.
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Affiliation(s)
- Jiaying Li
- Membrane
Science and Technology, MESA+ Institute for Nanotechnology, University of Twente, Faculty of Science and Technology, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | | | - Gerard van Ewijk
- AkzoNobel,
Decorative Coatings B.V., Rijksstraatweg 31, 2171 AJ Sassenheim, The Netherlands
| | | | - Wiebe M. de Vos
- Membrane
Science and Technology, MESA+ Institute for Nanotechnology, University of Twente, Faculty of Science and Technology, P.O. Box 217, 7500 AE Enschede, The Netherlands
| | - Jasper van der Gucht
- Physical
Chemistry and Soft Matter, Wageningen University
and Research, 6708 WEWageningen, The Netherlands
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3
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Nakatsuji M, Sato N, Sakamoto S, Watanabe K, Teruuchi Y, Takeuchi M, Inui T, Ishihara H. Non-electrostatic interactions associated with aggregate formation between polyallylamine and Escherichia coli. Sci Rep 2023; 13:14793. [PMID: 37684326 PMCID: PMC10491771 DOI: 10.1038/s41598-023-42120-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 09/05/2023] [Indexed: 09/10/2023] Open
Abstract
Bacterial aggregation by mixing with polymers is applied as pretreatment to identify pathogens in patients with infectious diseases. However, the detailed interaction between polymers and bacteria has yet to be fully understood. Here, we investigate the interaction between polyallylamine and Escherichia coli by isothermal titration calorimetry. Aggregation was observed at pH 10 and the binding was driven by favorable enthalpic gain such as the electrostatic interaction. Neither aggregation nor the apparent heat of binding was observed at pH 4.0, despite the strong positive charge of polyallylamine. These results suggest that intermolecular repulsive forces of the abundant positive charge of polyallylamine cause an increased loss of conformational entropy by binding. Non-electrostatic interaction plays a critical role for aggregation.
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Affiliation(s)
- Masatoshi Nakatsuji
- Research and Development Headquarters, Nitto Boseki Co., Ltd., 2-4-1 Kojimachi, Chiyoda-ku, Tokyo, 102-8489, Japan
- Laboratory of Biological Macromolecules, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan
- Faculty of Pharmacy, Osaka Medical and Pharmaceutical University, 4-20-1 Nasahara, Takatsuki, Osaka, 569-1094, Japan
| | - Natsuki Sato
- Research and Development Headquarters, Nitto Boseki Co., Ltd., 2-4-1 Kojimachi, Chiyoda-ku, Tokyo, 102-8489, Japan
| | - Shiho Sakamoto
- Laboratory of Biological Macromolecules, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan
| | - Koji Watanabe
- Specialty Chemicals Division, Nittobo Medical Co., Ltd., 1 Shiojima, Fukuhara, Fukuyama, Koriyama, Fukushima, 963-8061, Japan
| | - Yoko Teruuchi
- Specialty Chemicals Division, Nittobo Medical Co., Ltd., 1 Shiojima, Fukuhara, Fukuyama, Koriyama, Fukushima, 963-8061, Japan
| | - Minoru Takeuchi
- Research and Development Headquarters, Nitto Boseki Co., Ltd., 2-4-1 Kojimachi, Chiyoda-ku, Tokyo, 102-8489, Japan
| | - Takashi Inui
- Laboratory of Biological Macromolecules, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan.
- Laboratory of Biological Macromolecules, Graduate School of Agriculture, Osaka Metropolitan University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka, 599-8531, Japan.
| | - Hideki Ishihara
- Research and Development Headquarters, Nitto Boseki Co., Ltd., 2-4-1 Kojimachi, Chiyoda-ku, Tokyo, 102-8489, Japan.
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Krishna B A, de Vos WM, Lindhoud S. Control over Charge Density by Tuning the Polyelectrolyte Type and Monomer Ratio in Saloplastic-Based Ion-Exchange Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:6874-6884. [PMID: 37126784 DOI: 10.1021/acs.langmuir.3c00497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Membranes based on polyelectrolyte complexes (PECs) can now be prepared through several sustainable, organic solvent-free approaches. A recently developed approach allows PECs made by stoichiometric mixing of polyelectrolytes to be hot-pressed into dense saloplastics, which then function as ion-exchange membranes. An important advantage of PECs is that tuning their properties can provide significant control over the properties of the fabricated materials, and thus over their separation properties. This work studies the effects of two key parameters─(a) ratio of mixing and (b) choice of polyelectrolytes─on the mechanical, material, and separation properties of their corresponding hot-pressed saloplastic-based ion-exchange membranes. By varying these two main parameters, charge density─the key property of any IEM─was found to be controllable. While studying several systems, including strong/strong, strong/weak, and weak/weak combinations of polyelectrolytes, it was observed that not all systems could be processed into saloplastic membranes. For the processable systems, expected trends were observed where a higher excess of one polyelectrolyte would lead to a more charged system, resulting in higher water uptake and better permselectivities. An anomaly was the polystyrenesulfonate-polyvinylamine system, which showed an opposite trend with a higher polycation ratio, leading to a more negative charge. Overall, we have found that it is possible to successfully fabricate saloplastic-based anion- and cation-exchange membranes with tunable charge densities through careful choice of polyelectrolyte combination and ratio of mixing.
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Affiliation(s)
- Ameya Krishna B
- Membrane Surface Science, Membrane Science and Technology, MESA+ Institute of Nanotechnology, University of Twente, Enschede, Overijssel 7500 AE, The Netherlands
- Department of Molecules and Materials, University of Twente, Enschede, Overijssel 7500 AE, The Netherlands
| | - Wiebe M de Vos
- Membrane Surface Science, Membrane Science and Technology, MESA+ Institute of Nanotechnology, University of Twente, Enschede, Overijssel 7500 AE, The Netherlands
| | - Saskia Lindhoud
- Department of Molecules and Materials, University of Twente, Enschede, Overijssel 7500 AE, The Netherlands
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5
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Haque Mizan MM, Rastgar M, Aktij SA, Asad A, Karami P, Rahimpour A, Sadrzadeh M. Organic solvent-free polyelectrolyte complex membrane preparation: Effect of monomer mixing ratio and casting solution temperature. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2022.121197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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7
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Preparation and Characterizations of PSS/PDADMACPolyelectrolyte Complex Hydrogel. Polymers (Basel) 2022; 14:polym14091699. [PMID: 35566868 PMCID: PMC9103824 DOI: 10.3390/polym14091699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 04/14/2022] [Accepted: 04/20/2022] [Indexed: 12/10/2022] Open
Abstract
Polyelectrolyte complex (PEC) hydrogel, formed via physically electrostatic crosslinks between polyanion and polycation, is an interesting hydrogel in terms of its nontoxicity and solvent-free technique. In this work, poly (sodium 4-styrenesulfonate) (PSS)/poly (diallyl dimethyl ammonium chloride) (PDADMAC) complex hydrogels were prepared. Firstly, the PSS/PDADMAC complex aggregates using various PSS/PDADMAC mole fractions that were prepared in the presence of NaCl solution. Then, the aggregates were resolubilized under stirring at 70 °C for 2 h to obtain a homogeneous PEC solution. Finally, the PEC solution was dialyzed using a dialysis membrane with 3500 molecular cut-off for 1 day. The dialysis bath was changed every interval period of 2 h to control the rate of reversible electrostatic interaction, resulting in the homogenous PEC hydrogel with porous morphology as revealed by SEM and BET investigations. The dimensional stability and viscoelasticity of the PEC hydrogel was studied by DMA experiment, which showed the viscoelastic behavior at a compressive force ranging from 0 to 0.1 N. Finally, PSS/PDADMAC hydrogels showed a high water absorbency property and excellent affinity to textile anionic dyes.
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8
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Tu G, Li S, Han Y, Li Z, Liu J, Liu X, Li W. Fabrication of chitosan membranes via aqueous phase separation: Comparing the use of acidic and alkaline dope solutions. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2022.120256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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9
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Din J, Wu H, Wu P. One-Step Water-Induced Phase Separation Simultaneously Triggering Polymer Solidification and Polyelectrolyte Complexation for Porous Ultrafiltration Membranes. ACS APPLIED MATERIALS & INTERFACES 2022; 14:8482-8489. [PMID: 35113528 DOI: 10.1021/acsami.1c24059] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Functional additives have been widely utilized for the membrane structure modulation and performance improvement during the nonsolvent-induced phase separation process, but the resulted membranes easily suffer from additives' inhomogeneous dispersity and compatibility with the polymer matrix. Herein, a facile and robust strategy, i.e., one-step water-induced phase separation, was proposed for the preparation of polyelectrolytes-contained composite membranes. Polyanion (dopamine modified polyacrylic acid) and polycation (quaternized chitosan paired with bis(trifluoromethane-sulfonyl)imide) were first premixed in dimethyl sulfoxide and used as polyelectrolyte additives in a polysulfone (PSF) solution, and then a uniform PSF-based casting solution was readily obtained. During the solvent-water exchange process, polymer solidification and polyelectrolyte complexation were simultaneously triggered, in situ generating a polyelectrolyte complex fixed within the membrane matrix. Ultrafiltration membranes with hierarchical structures were notably tailored through altering the concentration, molecular weight, and type of polyelectrolytes. The obtained membrane exhibited a water flux of 672 L·m-2·h-1, three times over the raw PSF membrane, while almost maintaining high bovine serum albumin (BSA) rejection. This work paves a straightforward and convenient path for the preparation of composite membranes with tunable architecture and properties.
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Affiliation(s)
- Jincheng Din
- Key Laboratory of Science & Technology of Eco-Textile, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China
- School of Chemistry and Environmental Engineering, Yancheng Teachers University, Yancheng, Jiangsu 224007, China
- National Innovation Center of Advanced Dyeing and Finishing Technology, Tai'an, Shandong 271000, China
| | - Huiqing Wu
- Key Laboratory of Science & Technology of Eco-Textile, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China
- National Innovation Center of Advanced Dyeing and Finishing Technology, Tai'an, Shandong 271000, China
| | - Peiyi Wu
- Key Laboratory of Science & Technology of Eco-Textile, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620, China
- National Innovation Center of Advanced Dyeing and Finishing Technology, Tai'an, Shandong 271000, China
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10
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Baig M, Pejman M, Willott JD, Tiraferri A, de Vos WM. Polyelectrolyte Complex Hollow Fiber Membranes Prepared via Aqueous Phase Separation. ACS APPLIED POLYMER MATERIALS 2022; 4:1010-1020. [PMID: 35178524 PMCID: PMC8845049 DOI: 10.1021/acsapm.1c01464] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/29/2021] [Indexed: 05/08/2023]
Abstract
Hollow fiber (HF) membrane geometry is the preferred choice for most commercial membrane operations. Such fibers are conventionally prepared via the non-solvent-induced phase separation technique, which heavily relies on hazardous and reprotoxic organic solvents such as N-methyl pyrrolidone. A more sustainable alternative, i.e., aqueous phase separation (APS), was introduced recently that utilizes water as a solvent and non-solvent for the production of polymeric membranes. Herein, for the first time, we demonstrate the preparation of sustainable and functional HF membranes via the APS technique in a dry-jet wet spinning process. The dope solution comprising poly(sodium 4-styrenesulfonate) (PSS) and polyethyleneimine (PEI) at high pH along with an aqueous bore liquid is pushed through a single orifice spinneret into a low pH acetate buffer coagulation bath. Here, PEI becomes charged resulting in the formation of a polyelectrolyte complex with PSS. The compositions of the bore liquid and coagulation bath were systematically varied to study their effect on the structure and performance of the HF membranes. The microfiltration-type membranes (permeability ∼500 to 800 L·m-2·h-1·bar-1) with complete retention of emulsion droplets were obtained when the precipitation rate was slow. Increasing the concentration of the acetate buffer in the bath led to the increase in precipitation rate resulting in ultrafiltration-type membranes (permeability ∼12 to 15 L·m-2·h-1·bar-1) having molecular weight cut-offs in the range of ∼7.8-11.6 kDa. The research presented in this work confirms the versatility of APS and moves it another step closer to large-scale use.
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Affiliation(s)
- Muhammad
Irshad Baig
- Faculty
of Science and Technology, Membrane Science and Technology, MESA+
Institute for Nanotechnology, University
of Twente, P.O. Box 217, Enschede 7500 AE, The
Netherlands
| | - Mehdi Pejman
- Faculty
of Science and Technology, Membrane Science and Technology, MESA+
Institute for Nanotechnology, University
of Twente, P.O. Box 217, Enschede 7500 AE, The
Netherlands
- Department
of Environment, Land and Infrastructure Engineering (DIATI), Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin 10129, Italy
| | - Joshua D. Willott
- Faculty
of Science and Technology, Membrane Science and Technology, MESA+
Institute for Nanotechnology, University
of Twente, P.O. Box 217, Enschede 7500 AE, The
Netherlands
| | - Alberto Tiraferri
- Department
of Environment, Land and Infrastructure Engineering (DIATI), Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin 10129, Italy
| | - Wiebe M. de Vos
- Faculty
of Science and Technology, Membrane Science and Technology, MESA+
Institute for Nanotechnology, University
of Twente, P.O. Box 217, Enschede 7500 AE, The
Netherlands
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11
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Solvent and pH Stability of Poly(styrene-alt-maleic acid) (PSaMA) Membranes Prepared by Aqueous Phase Separation (APS). MEMBRANES 2021; 11:membranes11110835. [PMID: 34832064 PMCID: PMC8624750 DOI: 10.3390/membranes11110835] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 10/25/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022]
Abstract
In the single-polyelectrolyte aqueous phase separation (APS) approach, membranes are prepared by precipitating a weak polyelectrolyte from a concentrated aqueous solution using a pH switch. This has proven to be a versatile and more sustainable method compared to conventional approaches as it significantly reduces the use of organic solvents. Poly(styrene-alt-maleic acid) (PSaMA) is a polymer that has been extensively investigated for APS and has been the basis for both open and dense membranes with good performances. These membranes are chemically crosslinked and, in this work, we further investigated ultrafiltration (UF) and nanofiltration (NF) membranes prepared with PSaMA for their stability in various organic solvents and under different pH conditions. It was shown that these membranes had stable performances in both isopropanol (IPA) and toluene, and a slightly reduced performance in N-methyl-2-pyrollidone (NMP). However, PSaMA did not perform well as a selective layer in these solvents, indicating that the real opportunity would be to use the UF-type PSaMA membranes as solvent-stable support membranes. Additionally, the membranes proved to be stable in an acidic-to-neutral pH regime (pH 2–7); and, due to the pH-responsive nature of PSaMA, for the NF membranes, a pH-dependent retention of Mg2+ and SO42− ions was observed and, for the UF membranes, a strong responsive behavior was observed, where the pH can be used to control the membrane permeability. However, long-term exposure to elevated pH conditions (pH 8–10) resulted in severe swelling of the NF membranes, resulting in defect formation, and compaction of the UF membranes. For the UF membranes, this compaction did prove to be reversible for some but not all of the membrane samples measured. These results showed that in aqueous systems, membranes prepared with PSaMA had interesting responsive behaviors but performed best at neutral and acidic pH values. Moreover, the membranes exhibited excellent stability in the organic solvents IPA and toluene
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Baig M, Willott JD, de Vos WM. Enhancing the Separation Performance of Aqueous Phase Separation-Based Membranes through Polyelectrolyte Multilayer Coatings and Interfacial Polymerization. ACS APPLIED POLYMER MATERIALS 2021; 3:3560-3568. [PMID: 34278307 PMCID: PMC8276274 DOI: 10.1021/acsapm.1c00457] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 06/14/2021] [Indexed: 06/13/2023]
Abstract
The aqueous phase separation (APS) technique allows membrane fabrication without use of unsustainable organic solvents, while at the same time, it provides extensive control over membrane pore size and morphology. Herein, we investigate if polyelectrolyte complexation-induced APS ultrafiltration membranes can be the basis for different types of nanofiltration membranes. We demonstrate that APS membranes can be used as support membranes for functional surface coatings like thin polyelectrolyte multilayer (PEMs) and interfacial polymerization (IP) coatings. Three different PEMs were fabricated on poly(sodium 4-styrene sulfonate) (PSS) poly(allylamine hydrochloride) (PAH) APS ultrafiltration membranes, and only 4.5 bilayers were needed to create nanofiltration membranes with molecular weight cut-off (MWCO) values of 210-390 Da while maintaining a roughly constant water permeability (∼1.7 L·m-2·h-1·bar-1). The PEM-coated membranes showed excellent MgCl2 (∼98%), NaCl (∼70%), and organic micropollutant retention values (>90%). Similarly, fabricating thin polyamide layers on the ultrafiltration PSS-PAH APS membranes by IP resulted in nanofiltration membranes with MWCO values of ∼200 Da. This work shows for the first time that APS membranes can indeed be utilized as excellent support membranes for the application of functional coatings without requiring any form of pretreatment.
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Nielen WM, Willott JD, Galicia JAR, de Vos WM. Effect of Solution Viscosity on the Precipitation of PSaMA in Aqueous Phase Separation-Based Membrane Formation. Polymers (Basel) 2021; 13:polym13111775. [PMID: 34071412 PMCID: PMC8198088 DOI: 10.3390/polym13111775] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/21/2021] [Accepted: 05/25/2021] [Indexed: 11/16/2022] Open
Abstract
Aqueous phase separation (APS) is a recently developed sustainable alternative to the conventional organic solvent based nonsolvent-induced phase separation (NIPS) method to prepare polymeric membranes. In APS, polyelectrolytes are precipitated from aqueous solutions through pH or salinity switches. Although APS differs from NIPS in the polymer and solvents, they share many tuning parameters. In this work, we investigate the APS-based preparation of membranes from poly(styrene-alt-maleic acid) (PSaMA) with a focus on acid concentration in the coagulation bath, and polymer and additive concentration in the casting solution. Nanofiltration membranes are prepared using significantly lower concentrations of acid: 0.3 M HCl compared to the 2 M of either acetic or phosphoric acid used in previous works. It is shown that higher polymer concentrations can be used to prevent defect formation in the top layer. In addition, acetic acid concentration also strongly affects casting solution viscosity and thus can be used to control membrane structure, where lower acetic acid concentrations can prevent the formation of macrovoids in the support structure. The prepared nanofiltration membranes exhibit a very low molecular weight cutoff (210 ± 40 dalton), making these sustainable membranes very relevant for the removal of contaminants of emerging concern. Understanding how the parameters described here affect membrane preparation and performance is essential to optimizing membranes prepared with APS towards this important application.
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Baig MI, Sari PPI, Li J, Willott JD, de Vos WM. Sustainable Aqueous Phase Separation membranes prepared through mild pH shift induced polyelectrolyte complexation of PSS and PEI. J Memb Sci 2021. [DOI: 10.1016/j.memsci.2021.119114] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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15
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Weak polyanion and strong polycation complex based membranes: Linking aqueous phase separation to traditional membrane fabrication. Eur Polym J 2020. [DOI: 10.1016/j.eurpolymj.2020.110015] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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