Polyelectrolyte complex membranes for pervaporation, nanofiltration and fuel cell applications

Zhao, Qiang; An, Quanfu F.; Ji, Yan-Li; Qian, Jinwen; Gao, Congjie

doi:10.1016/j.memsci.2011.06.016

Cited by 227 publications

(115 citation statements)

References 211 publications

(316 reference statements)

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“…Common examples of PEs include biologically important molecules like DNA, RNA and proteins [1][2][3] . PEs also find applications in industries such as chemical [4][5][6][7] , pharmaceutical [8][9][10][11] , food 12,13 etc. The mechanical and chemical properties of a PE depend on its conformational state, which could vary from being linear and extended to compact and collapsed.…”

Section: Introductionmentioning

confidence: 99%

Regimes of electrostatic collapse of a highly charged polyelectrolyte in a poor solvent

et al. 2017

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We perform extensive molecular dynamics simulations of a highly charged, collapsed, flexible polyelectrolyte chain in a poor solvent for the case when the electrostatic interactions, characterized by the reduced Bjerrum length B , are strong. We find the existence of several sub-regimes in the dependence of the gyration radius of the chain R g on B characterized by R g ∼ −γ B . In contrast to a good solvent, the exponent γ for a poor solvent crucially depends on the size and valency of counterions. To explain the different sub-regimes, we generalize the existing counterion fluctuation theory by including a more complete account of all possible volume interactions in the free energy of the polyelectrolyte chain. We also show that the presence of the condensed counterions modifies the effective attraction among the chain monomers and modulates the sign of the second virial coefficient in poor solvent conditions.

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Section: Introductionmentioning

confidence: 99%

Regimes of electrostatic collapse of a highly charged polyelectrolyte in a poor solvent

et al. 2017

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“…[10,11] In order to apply films composed of oppositely charged polyelectrolytes to substrates using just one or two deposition steps, solutions containing polyelectrolyte complexes (PECs) can be employed. [12][13][14][15] PECs are formed by the entropy-driven association of oppositely charged polyelectrolytes in water and can exist as stable colloids, flocculants, or metastable coacervates. [16][17][18][19][20] Governed by conditions such as pH and ionic strength, PEC coacervation is marked by a liquid-liquid phase separation, where a polymer rich coacervate phase is in equilibrium with a polymer poor solution phase.…”

mentioning

confidence: 99%

Polyelectrolyte Coacervates Deposited as High Gas Barrier Thin Films

Haile

Sarwar

Henderson

et al. 2016

Macromol. Rapid Commun.

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Multilayer films deposited from water using layer-by-layer (LbL) assembly have shown extraordinarily low oxygen permeability and are of high interest due to their robustness, tailorability, and ease of fabrication. [5][6][7][8][9] Despite all the advantages associated with LbL assembly, the large number of processing steps remains a considerable challenge for commercial use. [10,11] In order to apply films composed of oppositely charged polyelectrolytes to substrates using just one or two deposition steps, solutions containing polyelectrolyte complexes (PECs) can be employed. [12][13][14][15] PECs are formed by the entropy-driven association of oppositely charged polyelectrolytes in water and can exist as stable colloids, flocculants, or metastable coacervates. [16][17][18][19][20] Governed by conditions such as pH and ionic strength, PEC coacervation is marked by a liquid-liquid phase separation, where a polymer rich coacervate phase is in equilibrium with a polymer poor solution phase. PEC coacervates are composed of weakly bound polyelectrolytes, and have viscous liquid-like behavior that can be exploited to quickly apply them as thin films. [18,[21][22][23][24] In the present study, polyelectrolyte coacervates were applied to substrates using Meyer rod coating (a common type of blade coating), [25] in an effort to quickly fabricate thin oxygen barrier films in a single step. The Meyer rod is drawn across a substrate, doctoring off coating fluid, Multilayer coatings consisting of oppositely charged polyelectrolytes have proven to be extraordinarily effective oxygen barriers but require many processing steps to fabricate. In an effort to prepare high oxygen barrier thin films more quickly, a polyelectrolyte complex coacervate composed of polyethylenimine and polyacrylic acid is prepared. The coacervate fluid is applied as a thin film using a rod coating process. With humidity and thermal posttreatment, a 2 µm thin film reduces the oxygen transmission rate of 0.127 mm poly(ethylene terephthalate) by two orders of magnitude, rivalling conventional oxygen barrier technologies. These films are fabricated in ambient conditions using low-cost, water-based solutions, providing a tremendous opportunity for single-step deposition of polymeric high barrier thin films.

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“…Membrane surface charge can be improved by grafting some negatively charged groups to membrane surface [14]. Moreover, using polyelectrolyte-polyelectrolyte complexes strategy could render membranes tunable surface charge [37]. Recently, Lin et al [3] reviewed the factors affecting zeta potential of sludge foulants, which include EPSs content, proteins to polysaccharides (PN/PS) ratio, organic loading rate, SRT, pH, addition of the additives and etc.…”

Section: Implications For Membrane Fouling Mitigationmentioning

confidence: 99%

Effects of surface charge on interfacial interactions related to membrane fouling in a submerged membrane bioreactor based on thermodynamic analysis

Cai

Fan

Zhao

et al. 2016

Journal of Colloid and Interface Science

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Polyelectrolyte complex membranes for pervaporation, nanofiltration and fuel cell applications

Cited by 227 publications

References 211 publications

Regimes of electrostatic collapse of a highly charged polyelectrolyte in a poor solvent

Regimes of electrostatic collapse of a highly charged polyelectrolyte in a poor solvent

Polyelectrolyte Coacervates Deposited as High Gas Barrier Thin Films

Effects of surface charge on interfacial interactions related to membrane fouling in a submerged membrane bioreactor based on thermodynamic analysis

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