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Nanostructure of Unconventional Liquid Crystals Investigated by Synchrotron Radiation

The macroscopic properties of novel liquid crystal (LC) systems—LCs with unconventional molecular structure as well as conventional LCs in unconventional geometries—directly descend from their mesoscopic structural organization. While X-ray diffraction (XRD) is an obvious choice to investigate their...

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Autores principales: Vita, Francesco, Adamo, Fabrizio Corrado, Pisani, Michela, Francescangeli, Oriano
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7558469/
https://www.ncbi.nlm.nih.gov/pubmed/32859117
http://dx.doi.org/10.3390/nano10091679
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author Vita, Francesco
Adamo, Fabrizio Corrado
Pisani, Michela
Francescangeli, Oriano
author_facet Vita, Francesco
Adamo, Fabrizio Corrado
Pisani, Michela
Francescangeli, Oriano
author_sort Vita, Francesco
collection PubMed
description The macroscopic properties of novel liquid crystal (LC) systems—LCs with unconventional molecular structure as well as conventional LCs in unconventional geometries—directly descend from their mesoscopic structural organization. While X-ray diffraction (XRD) is an obvious choice to investigate their nanoscale structure, conventional diffractometry is often hampered by experimental difficulties: the low scattering power and short-range positional order of the materials, resulting in weak and diffuse diffraction features; the need to perform measurements in challenging conditions, e.g., under magnetic and/or electric fields, on thin films, or at high temperatures; and the necessity to probe micron-sized volumes to tell the local structural properties from their macroscopic average. Synchrotron XRD allows these problems to be circumvented thanks to the superior diffraction capabilities (brilliance, q-range, energy and space resolution) and advanced sample environment available at synchrotron beamlines. Here, we highlight the potentiality of synchrotron XRD in the field of LCs by reviewing a selection of experiments on three unconventional LC systems: the potentially biaxial and polar nematic phase of bent-core mesogens; the very high-temperature nematic phase of all-aromatic LCs; and polymer-dispersed liquid crystals. In all these cases, synchrotron XRD unveils subtle nanostructural features that are reflected into macroscopic properties of great interest from both fundamental and technological points of view.
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spelling pubmed-75584692020-10-26 Nanostructure of Unconventional Liquid Crystals Investigated by Synchrotron Radiation Vita, Francesco Adamo, Fabrizio Corrado Pisani, Michela Francescangeli, Oriano Nanomaterials (Basel) Review The macroscopic properties of novel liquid crystal (LC) systems—LCs with unconventional molecular structure as well as conventional LCs in unconventional geometries—directly descend from their mesoscopic structural organization. While X-ray diffraction (XRD) is an obvious choice to investigate their nanoscale structure, conventional diffractometry is often hampered by experimental difficulties: the low scattering power and short-range positional order of the materials, resulting in weak and diffuse diffraction features; the need to perform measurements in challenging conditions, e.g., under magnetic and/or electric fields, on thin films, or at high temperatures; and the necessity to probe micron-sized volumes to tell the local structural properties from their macroscopic average. Synchrotron XRD allows these problems to be circumvented thanks to the superior diffraction capabilities (brilliance, q-range, energy and space resolution) and advanced sample environment available at synchrotron beamlines. Here, we highlight the potentiality of synchrotron XRD in the field of LCs by reviewing a selection of experiments on three unconventional LC systems: the potentially biaxial and polar nematic phase of bent-core mesogens; the very high-temperature nematic phase of all-aromatic LCs; and polymer-dispersed liquid crystals. In all these cases, synchrotron XRD unveils subtle nanostructural features that are reflected into macroscopic properties of great interest from both fundamental and technological points of view. MDPI 2020-08-26 /pmc/articles/PMC7558469/ /pubmed/32859117 http://dx.doi.org/10.3390/nano10091679 Text en © 2020 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 Review
Vita, Francesco
Adamo, Fabrizio Corrado
Pisani, Michela
Francescangeli, Oriano
Nanostructure of Unconventional Liquid Crystals Investigated by Synchrotron Radiation
title Nanostructure of Unconventional Liquid Crystals Investigated by Synchrotron Radiation
title_full Nanostructure of Unconventional Liquid Crystals Investigated by Synchrotron Radiation
title_fullStr Nanostructure of Unconventional Liquid Crystals Investigated by Synchrotron Radiation
title_full_unstemmed Nanostructure of Unconventional Liquid Crystals Investigated by Synchrotron Radiation
title_short Nanostructure of Unconventional Liquid Crystals Investigated by Synchrotron Radiation
title_sort nanostructure of unconventional liquid crystals investigated by synchrotron radiation
topic Review
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7558469/
https://www.ncbi.nlm.nih.gov/pubmed/32859117
http://dx.doi.org/10.3390/nano10091679
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