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Phase Transition Effects on Mechanical Properties of NIPA Hydrogel

Due to its excellent temperature sensitivity, the Poly(N-isopropylacrylamide) (NIPA) hydrogel has attracted great interest for a wide variety of applications in tissue engineering and regenerative medicine. NIPA hydrogel undergoes an abrupt volume phase transition at a lower critical solution temper...

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Autores principales: Zhang, Ni, Zheng, Shoujing, Pan, Zhouzhou, Liu, Zishun
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6414852/
https://www.ncbi.nlm.nih.gov/pubmed/30966393
http://dx.doi.org/10.3390/polym10040358
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author Zhang, Ni
Zheng, Shoujing
Pan, Zhouzhou
Liu, Zishun
author_facet Zhang, Ni
Zheng, Shoujing
Pan, Zhouzhou
Liu, Zishun
author_sort Zhang, Ni
collection PubMed
description Due to its excellent temperature sensitivity, the Poly(N-isopropylacrylamide) (NIPA) hydrogel has attracted great interest for a wide variety of applications in tissue engineering and regenerative medicine. NIPA hydrogel undergoes an abrupt volume phase transition at a lower critical solution temperature (LCST) of 30–35 °C. However, the mechanical behaviors of NIPA hydrogel induced by phase transition are still not well understood. In this study, phase transition effects on mechanical properties of NIPA hydrogel are quantitatively studied from experimental studies. The mechanical properties of NIPA hydrogel with the LSCT around 35 °C are systemically studied with varying temperatures (31–39 °C) under a tensile test. We find that the mechanical properties of NIPA hydrogel are greatly influenced by phase transition during the tension process. The maximum nominal stress and maximum stretch above the LCST are larger than those of below the LCST. The Young’s modulus of NIPA hydrogel is around 13 kPa at 31 °C and approximately 28 kPa at 39 °C. A dramatic increase of Young’s modulus values is observed as the temperature increases through the phase transition. The samples at a temperature around the LCST are easy to rupture, because of phase coexistent. Additionally, NIPA hydrogel displays toughening behavior under a cyclic load. Furthermore, the toughening characteristic is different between the swollen state and the collapsed state. This might originate from the internal fracture process and redistribution of polymer chains during the tension process.
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spelling pubmed-64148522019-04-02 Phase Transition Effects on Mechanical Properties of NIPA Hydrogel Zhang, Ni Zheng, Shoujing Pan, Zhouzhou Liu, Zishun Polymers (Basel) Article Due to its excellent temperature sensitivity, the Poly(N-isopropylacrylamide) (NIPA) hydrogel has attracted great interest for a wide variety of applications in tissue engineering and regenerative medicine. NIPA hydrogel undergoes an abrupt volume phase transition at a lower critical solution temperature (LCST) of 30–35 °C. However, the mechanical behaviors of NIPA hydrogel induced by phase transition are still not well understood. In this study, phase transition effects on mechanical properties of NIPA hydrogel are quantitatively studied from experimental studies. The mechanical properties of NIPA hydrogel with the LSCT around 35 °C are systemically studied with varying temperatures (31–39 °C) under a tensile test. We find that the mechanical properties of NIPA hydrogel are greatly influenced by phase transition during the tension process. The maximum nominal stress and maximum stretch above the LCST are larger than those of below the LCST. The Young’s modulus of NIPA hydrogel is around 13 kPa at 31 °C and approximately 28 kPa at 39 °C. A dramatic increase of Young’s modulus values is observed as the temperature increases through the phase transition. The samples at a temperature around the LCST are easy to rupture, because of phase coexistent. Additionally, NIPA hydrogel displays toughening behavior under a cyclic load. Furthermore, the toughening characteristic is different between the swollen state and the collapsed state. This might originate from the internal fracture process and redistribution of polymer chains during the tension process. MDPI 2018-03-23 /pmc/articles/PMC6414852/ /pubmed/30966393 http://dx.doi.org/10.3390/polym10040358 Text en © 2018 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
Zhang, Ni
Zheng, Shoujing
Pan, Zhouzhou
Liu, Zishun
Phase Transition Effects on Mechanical Properties of NIPA Hydrogel
title Phase Transition Effects on Mechanical Properties of NIPA Hydrogel
title_full Phase Transition Effects on Mechanical Properties of NIPA Hydrogel
title_fullStr Phase Transition Effects on Mechanical Properties of NIPA Hydrogel
title_full_unstemmed Phase Transition Effects on Mechanical Properties of NIPA Hydrogel
title_short Phase Transition Effects on Mechanical Properties of NIPA Hydrogel
title_sort phase transition effects on mechanical properties of nipa hydrogel
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6414852/
https://www.ncbi.nlm.nih.gov/pubmed/30966393
http://dx.doi.org/10.3390/polym10040358
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