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Activation volume of selected liquid crystals in the density scaling regime
In this paper, we demonstrate and thoroughly analyze the activation volumetric properties of selected liquid crystals in the nematic and crystalline E phases in comparison with those reported for glass-forming liquids. In the analysis, we have employed and evaluated two entropic models (based on eit...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5299607/ https://www.ncbi.nlm.nih.gov/pubmed/28181530 http://dx.doi.org/10.1038/srep42174 |
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author | Grzybowski, A. Urban, S. Mroz, S. Paluch, M. |
author_facet | Grzybowski, A. Urban, S. Mroz, S. Paluch, M. |
author_sort | Grzybowski, A. |
collection | PubMed |
description | In this paper, we demonstrate and thoroughly analyze the activation volumetric properties of selected liquid crystals in the nematic and crystalline E phases in comparison with those reported for glass-forming liquids. In the analysis, we have employed and evaluated two entropic models (based on either total or configurational entropies) to describe the longitudinal relaxation times of the liquid crystals in the density scaling regime. In this study, we have also exploited two equations of state: volumetric and activation volumetric ones. As a result, we have established that the activation volumetric properties of the selected liquid crystals are quite opposite to such typical properties of glass-forming materials, i.e., the activation volume decreases and the isothermal bulk modulus increases when a liquid crystal is isothermally compressed. Using the model based on the configurational entropy, we suggest that the increasing pressure dependences of the activation volume in isothermal conditions and the negative curvature of the pressure dependences of isothermal longitudinal relaxation times can be related to the formation of antiparallel doublets in the examined liquid crystals. A similar pressure effect on relaxation dynamics may be also observed for other material groups in case of systems, the molecules of which form some supramolecular structures. |
format | Online Article Text |
id | pubmed-5299607 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Nature Publishing Group |
record_format | MEDLINE/PubMed |
spelling | pubmed-52996072017-02-13 Activation volume of selected liquid crystals in the density scaling regime Grzybowski, A. Urban, S. Mroz, S. Paluch, M. Sci Rep Article In this paper, we demonstrate and thoroughly analyze the activation volumetric properties of selected liquid crystals in the nematic and crystalline E phases in comparison with those reported for glass-forming liquids. In the analysis, we have employed and evaluated two entropic models (based on either total or configurational entropies) to describe the longitudinal relaxation times of the liquid crystals in the density scaling regime. In this study, we have also exploited two equations of state: volumetric and activation volumetric ones. As a result, we have established that the activation volumetric properties of the selected liquid crystals are quite opposite to such typical properties of glass-forming materials, i.e., the activation volume decreases and the isothermal bulk modulus increases when a liquid crystal is isothermally compressed. Using the model based on the configurational entropy, we suggest that the increasing pressure dependences of the activation volume in isothermal conditions and the negative curvature of the pressure dependences of isothermal longitudinal relaxation times can be related to the formation of antiparallel doublets in the examined liquid crystals. A similar pressure effect on relaxation dynamics may be also observed for other material groups in case of systems, the molecules of which form some supramolecular structures. Nature Publishing Group 2017-02-09 /pmc/articles/PMC5299607/ /pubmed/28181530 http://dx.doi.org/10.1038/srep42174 Text en Copyright © 2017, The Author(s) http://creativecommons.org/licenses/by/4.0/ This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ |
spellingShingle | Article Grzybowski, A. Urban, S. Mroz, S. Paluch, M. Activation volume of selected liquid crystals in the density scaling regime |
title | Activation volume of selected liquid crystals in the density scaling regime |
title_full | Activation volume of selected liquid crystals in the density scaling regime |
title_fullStr | Activation volume of selected liquid crystals in the density scaling regime |
title_full_unstemmed | Activation volume of selected liquid crystals in the density scaling regime |
title_short | Activation volume of selected liquid crystals in the density scaling regime |
title_sort | activation volume of selected liquid crystals in the density scaling regime |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5299607/ https://www.ncbi.nlm.nih.gov/pubmed/28181530 http://dx.doi.org/10.1038/srep42174 |
work_keys_str_mv | AT grzybowskia activationvolumeofselectedliquidcrystalsinthedensityscalingregime AT urbans activationvolumeofselectedliquidcrystalsinthedensityscalingregime AT mrozs activationvolumeofselectedliquidcrystalsinthedensityscalingregime AT paluchm activationvolumeofselectedliquidcrystalsinthedensityscalingregime |