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Side Chains and the Insufficient Lubrication of Water in Polyacrylamide Hydrogel—A New Insight
Existing theories cannot predict the mechanical property changes of polyacrylamide hydrogels with different water content because of the absence of side chains. In this study, polyacrylamide hydrogels are prepared and tested to investigate the side chain effect on their mechanical properties. First,...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2019
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6918331/ https://www.ncbi.nlm.nih.gov/pubmed/31717453 http://dx.doi.org/10.3390/polym11111845 |
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author | Lei, Jincheng Zhou, Zidi Liu, Zishun |
author_facet | Lei, Jincheng Zhou, Zidi Liu, Zishun |
author_sort | Lei, Jincheng |
collection | PubMed |
description | Existing theories cannot predict the mechanical property changes of polyacrylamide hydrogels with different water content because of the absence of side chains. In this study, polyacrylamide hydrogels are prepared and tested to investigate the side chain effect on their mechanical properties. First, the comparison between the effective chain density and total chain density provides proof of the large amount of side chains in the polymer network of PAAm hydrogel. We propose a practical chain density fraction to measure the side chain fraction. Then, the abnormal Young’s moduli-polymer volume fraction relationship reveals that side chains affect the mechanical properties of hydrogel through the insufficient lubrication of water. Water confined in narrow space within a molecular-level size can bear shear force to provide extra deformation resistance. A constitutive mode considering the effect of the insufficient lubrication of water is proposed. Combining this constitutive model with experimental results, we find that this insufficient lubrication of water exists even in equilibrium PAAm hydrogel. Molecular dynamics simulations reveal that this insufficient lubrication of water comes from the constraint of polymer chains. It also demonstrates that when there is insufficient lubrication, the rearrangement of water molecules leads to the persistent energy dissipation in the Mullins effect of PAAm hydrogel. |
format | Online Article Text |
id | pubmed-6918331 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-69183312019-12-24 Side Chains and the Insufficient Lubrication of Water in Polyacrylamide Hydrogel—A New Insight Lei, Jincheng Zhou, Zidi Liu, Zishun Polymers (Basel) Article Existing theories cannot predict the mechanical property changes of polyacrylamide hydrogels with different water content because of the absence of side chains. In this study, polyacrylamide hydrogels are prepared and tested to investigate the side chain effect on their mechanical properties. First, the comparison between the effective chain density and total chain density provides proof of the large amount of side chains in the polymer network of PAAm hydrogel. We propose a practical chain density fraction to measure the side chain fraction. Then, the abnormal Young’s moduli-polymer volume fraction relationship reveals that side chains affect the mechanical properties of hydrogel through the insufficient lubrication of water. Water confined in narrow space within a molecular-level size can bear shear force to provide extra deformation resistance. A constitutive mode considering the effect of the insufficient lubrication of water is proposed. Combining this constitutive model with experimental results, we find that this insufficient lubrication of water exists even in equilibrium PAAm hydrogel. Molecular dynamics simulations reveal that this insufficient lubrication of water comes from the constraint of polymer chains. It also demonstrates that when there is insufficient lubrication, the rearrangement of water molecules leads to the persistent energy dissipation in the Mullins effect of PAAm hydrogel. MDPI 2019-11-08 /pmc/articles/PMC6918331/ /pubmed/31717453 http://dx.doi.org/10.3390/polym11111845 Text en © 2019 by the authors. 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 (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Lei, Jincheng Zhou, Zidi Liu, Zishun Side Chains and the Insufficient Lubrication of Water in Polyacrylamide Hydrogel—A New Insight |
title | Side Chains and the Insufficient Lubrication of Water in Polyacrylamide Hydrogel—A New Insight |
title_full | Side Chains and the Insufficient Lubrication of Water in Polyacrylamide Hydrogel—A New Insight |
title_fullStr | Side Chains and the Insufficient Lubrication of Water in Polyacrylamide Hydrogel—A New Insight |
title_full_unstemmed | Side Chains and the Insufficient Lubrication of Water in Polyacrylamide Hydrogel—A New Insight |
title_short | Side Chains and the Insufficient Lubrication of Water in Polyacrylamide Hydrogel—A New Insight |
title_sort | side chains and the insufficient lubrication of water in polyacrylamide hydrogel—a new insight |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6918331/ https://www.ncbi.nlm.nih.gov/pubmed/31717453 http://dx.doi.org/10.3390/polym11111845 |
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