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Swelling and Collapse of Cylindrical Polyelectrolyte Microgels

In this study, we propose computer simulations of charged cylindrical microgels. The effects of cross-linking density, aspect ratio, and fraction of charged groups on the microgel swelling and collapse with a variation in the solvent quality were studied. The results were compared with those obtaine...

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Autores principales: Portnov, Ivan V., Larina, Alexandra A., Gumerov, Rustam A., Potemkin, Igor I.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9694774/
https://www.ncbi.nlm.nih.gov/pubmed/36433158
http://dx.doi.org/10.3390/polym14225031
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author Portnov, Ivan V.
Larina, Alexandra A.
Gumerov, Rustam A.
Potemkin, Igor I.
author_facet Portnov, Ivan V.
Larina, Alexandra A.
Gumerov, Rustam A.
Potemkin, Igor I.
author_sort Portnov, Ivan V.
collection PubMed
description In this study, we propose computer simulations of charged cylindrical microgels. The effects of cross-linking density, aspect ratio, and fraction of charged groups on the microgel swelling and collapse with a variation in the solvent quality were studied. The results were compared with those obtained for equivalent neutral cylindrical microgels. The study demonstrated that microgels’ degree of swelling strongly depends on the fraction of charged groups. Polyelectrolyte microgels under adequate solvent conditions are characterized by a larger length and thickness than their neutral analogues: the higher the fraction of charged groups, the longer their length and greater their thickness. Microgels’ collapse upon solvent quality decline is characterized by a decrease in length and non-monotonous behavior of its thickness. First, the thickness decreases due to the attraction of monomer units (beads) upon collapse. The further thickness increase is related to the surface tension, which tends to reduce the anisotropy of collapsed objects (the minimum surface energy is known to be achieved for the spherical objects). This reduction is opposed by the network elasticity. The microgels with a low cross-linking density and/or a low enough aspect ratio reveal a cylinder-to-sphere collapse. Otherwise, the cylindrical shape is preserved in the course of the collapse. Aspect ratio as a function of the solvent quality (interaction parameter) demonstrates the maximum, which is solely due to the electrostatics. Finally, we plotted radial concentration profiles for network segments, their charged groups, and counterions.
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spelling pubmed-96947742022-11-26 Swelling and Collapse of Cylindrical Polyelectrolyte Microgels Portnov, Ivan V. Larina, Alexandra A. Gumerov, Rustam A. Potemkin, Igor I. Polymers (Basel) Article In this study, we propose computer simulations of charged cylindrical microgels. The effects of cross-linking density, aspect ratio, and fraction of charged groups on the microgel swelling and collapse with a variation in the solvent quality were studied. The results were compared with those obtained for equivalent neutral cylindrical microgels. The study demonstrated that microgels’ degree of swelling strongly depends on the fraction of charged groups. Polyelectrolyte microgels under adequate solvent conditions are characterized by a larger length and thickness than their neutral analogues: the higher the fraction of charged groups, the longer their length and greater their thickness. Microgels’ collapse upon solvent quality decline is characterized by a decrease in length and non-monotonous behavior of its thickness. First, the thickness decreases due to the attraction of monomer units (beads) upon collapse. The further thickness increase is related to the surface tension, which tends to reduce the anisotropy of collapsed objects (the minimum surface energy is known to be achieved for the spherical objects). This reduction is opposed by the network elasticity. The microgels with a low cross-linking density and/or a low enough aspect ratio reveal a cylinder-to-sphere collapse. Otherwise, the cylindrical shape is preserved in the course of the collapse. Aspect ratio as a function of the solvent quality (interaction parameter) demonstrates the maximum, which is solely due to the electrostatics. Finally, we plotted radial concentration profiles for network segments, their charged groups, and counterions. MDPI 2022-11-20 /pmc/articles/PMC9694774/ /pubmed/36433158 http://dx.doi.org/10.3390/polym14225031 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Portnov, Ivan V.
Larina, Alexandra A.
Gumerov, Rustam A.
Potemkin, Igor I.
Swelling and Collapse of Cylindrical Polyelectrolyte Microgels
title Swelling and Collapse of Cylindrical Polyelectrolyte Microgels
title_full Swelling and Collapse of Cylindrical Polyelectrolyte Microgels
title_fullStr Swelling and Collapse of Cylindrical Polyelectrolyte Microgels
title_full_unstemmed Swelling and Collapse of Cylindrical Polyelectrolyte Microgels
title_short Swelling and Collapse of Cylindrical Polyelectrolyte Microgels
title_sort swelling and collapse of cylindrical polyelectrolyte microgels
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9694774/
https://www.ncbi.nlm.nih.gov/pubmed/36433158
http://dx.doi.org/10.3390/polym14225031
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