Environmentally responsive polyelectrolytes and zwitterionic polymers

Bernards, Matthew T.

doi:10.1016/b978-0-85709-713-2.00002-x

Cited by 2 publications

(3 citation statements)

References 89 publications

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“…Thus, at the IEP of a zwitterion, there is an overall charge balance in the polymer and the inter- and intrachain interactions are maximized, resulting in a compact configuration. − A change in the pH of the solution alters (slightly) its surface charge and, hence, the electrostatic interactions occurring with the ions in the solution. This phenomenon has been shown to occur with a change in pH by the loss of a tightly bound hydration layer . Therefore, single salts were allowed to interact with a freestanding solution of PFPA-Z to test the sequestering potential of the zwitterion without any influence of the polyamide membrane; and thereafter the rejection of the same ions was examined using PFPA-Z-grafted NF membranes.…”

Section: Resultsmentioning

confidence: 99%

“…This phenomenon has been shown to occur with a change in pH by the loss of a tightly bound hydration layer. 56 Therefore, single salts were allowed to interact with a freestanding solution of PFPA-Z to test the sequestering potential of the zwitterion without any influence of the polyamide membrane; and thereafter the rejection of the same ions was examined using PFPA-Z-grafted NF membranes. The PFPA-Z was investigated to determine the percentage of ions the zwitterion can sequester to understand the role of the grafted polymer.…”

Section: ■ Introductionmentioning

confidence: 99%

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Enhancing Polyvalent Cation Rejection Using Perfluorophenylazide-Grafted-Copolymer Membrane Coatings

Aguilar

Bustillos

Xue

et al. 2020

ACS Appl. Mater. Interfaces

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Surface modification offers a straightforward means to alter and enhance the properties and performance of materials, such as nanofiltration membranes for water softening. Herein, we demonstrate how a membrane's surface charge can be altered by grafting different electrostatically varying copolymers onto commercial membrane surfaces using perfluorophenylazide (PFPA) photochemistry for enhanced ion separation performance. The native membrane's performancei.e., in terms of divalent cation separationwith copolymer coatings containing a positively charged quaternary ammonium (−N(Me) 3 + ), a negatively charged sulfonate (−SO 3 − ), and an essentially neutral zwitterion (sulfobetaine, −N(Me) 2 R 2 + , and −SO 3 − ), respectively, indicates that: (a) the sulfonated polymer induces robust Coulombic exclusion of divalent anions as compared to the negatively charged native membrane surface on account of its higher negative charge; (b) the positively charged ammonium coating induces exclusion of cations more effectively than the native membrane; and significantly, (c) the zwitterion polymer coating, which reduces the surface roughness and improves wettability, in spite of its near-neutral charge enhances exclusion of both divalent cations and anions on account of aperture sieving by the compact zwitterion polymer that arises from its ability to limit the size of ions that transport through the polymer along with dielectric exclusion. The outcomes thereby inform new pathways to achieve size-and charge-based exclusion of ionic, molecular, and other species contained in liquid streams.

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Section: Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

Enhancing Polyvalent Cation Rejection Using Perfluorophenylazide-Grafted-Copolymer Membrane Coatings

Aguilar

Bustillos

Xue

et al. 2020

ACS Appl. Mater. Interfaces

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show abstract

“…The ionotropic gelation method has been utilized predominantly for the preparation of micro- and nanoparticles, synthesized by the addition of an anionic polyelectrolyte solution dropwise into an acidic chitosan solution. The anion polyelectrolyte solutions often contain alginate, carrageenan, xanthan, polyphosphates or organic sulfates [ 39 , 54 , 55 ]. Very recently phosphotungstates have been also successfully employed [ 9 ].…”

Section: An Overview Of Chitosan Properties and Methods Of Synthesmentioning

confidence: 99%

Ionotropic Gelation of Chitosan Flat Structures and Potential Applications

et al. 2021

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The capability of some polymers, such as chitosan, to form low cost gels under mild conditions is of great application interest. Ionotropic gelation of chitosan has been used predominantly for the preparation of gel beads for biomedical application. Only in the last few years has the use of this method been extended to the fabrication of chitosan-based flat structures. Herein, after an initial analysis of the major applications of chitosan flat membranes and films and their usual methods of synthesis, the process of ionotropic gelation of chitosan and some recently proposed novel procedures for the synthesis of flat structures are presented.

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Environmentally responsive polyelectrolytes and zwitterionic polymers

Cited by 2 publications

References 89 publications

Enhancing Polyvalent Cation Rejection Using Perfluorophenylazide-Grafted-Copolymer Membrane Coatings

Enhancing Polyvalent Cation Rejection Using Perfluorophenylazide-Grafted-Copolymer Membrane Coatings

Ionotropic Gelation of Chitosan Flat Structures and Potential Applications

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