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Nano-Structural Investigation on Cellulose Highly Dissolved in Ionic Liquid: A Small Angle X-ray Scattering Study

We investigated nano-structural changes of cellulose dissolved in 1-ethyl-3-methylimidazolium acetate—an ionic liquid (IL)—using a small angle X-ray scattering (SAXS) technique over the entire concentration range (0–100 mol %). Fibril structures of cellulose disappeared at 40 mol % of cellulose, whi...

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Autores principales: Endo, Takatsugu, Hosomi, Shota, Fujii, Shunsuke, Ninomiya, Kazuaki, Takahashi, Kenji
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2017
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6155725/
https://www.ncbi.nlm.nih.gov/pubmed/28117730
http://dx.doi.org/10.3390/molecules22010178
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author Endo, Takatsugu
Hosomi, Shota
Fujii, Shunsuke
Ninomiya, Kazuaki
Takahashi, Kenji
author_facet Endo, Takatsugu
Hosomi, Shota
Fujii, Shunsuke
Ninomiya, Kazuaki
Takahashi, Kenji
author_sort Endo, Takatsugu
collection PubMed
description We investigated nano-structural changes of cellulose dissolved in 1-ethyl-3-methylimidazolium acetate—an ionic liquid (IL)—using a small angle X-ray scattering (SAXS) technique over the entire concentration range (0–100 mol %). Fibril structures of cellulose disappeared at 40 mol % of cellulose, which is a significantly higher concentration than the maximum concentration of dissolution (24–28 mol %) previously determined in this IL. This behavior is explained by the presence of the anion bridging, whereby an anion prefers to interact with multiple OH groups of different cellulose molecules at high concentrations, discovered in our recent work. Furthermore, we observed the emergence of two aggregated nano-structures in the concentration range of 30–80 mol %. The diameter of one structure was 12–20 nm, dependent on concentration, which is ascribed to cellulose chain entanglement. In contrast, the other with 4.1 nm diameter exhibited concentration independence and is reminiscent of a cellulose microfibril, reflecting the occurrence of nanofibrillation. These results contribute to an understanding of the dissolution mechanism of cellulose in ILs. Finally, we unexpectedly proposed a novel cellulose/IL composite: the cellulose/IL mixtures of 30–50 mol % that possess liquid crystallinity are sufficiently hard to be moldable.
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spelling pubmed-61557252018-11-13 Nano-Structural Investigation on Cellulose Highly Dissolved in Ionic Liquid: A Small Angle X-ray Scattering Study Endo, Takatsugu Hosomi, Shota Fujii, Shunsuke Ninomiya, Kazuaki Takahashi, Kenji Molecules Article We investigated nano-structural changes of cellulose dissolved in 1-ethyl-3-methylimidazolium acetate—an ionic liquid (IL)—using a small angle X-ray scattering (SAXS) technique over the entire concentration range (0–100 mol %). Fibril structures of cellulose disappeared at 40 mol % of cellulose, which is a significantly higher concentration than the maximum concentration of dissolution (24–28 mol %) previously determined in this IL. This behavior is explained by the presence of the anion bridging, whereby an anion prefers to interact with multiple OH groups of different cellulose molecules at high concentrations, discovered in our recent work. Furthermore, we observed the emergence of two aggregated nano-structures in the concentration range of 30–80 mol %. The diameter of one structure was 12–20 nm, dependent on concentration, which is ascribed to cellulose chain entanglement. In contrast, the other with 4.1 nm diameter exhibited concentration independence and is reminiscent of a cellulose microfibril, reflecting the occurrence of nanofibrillation. These results contribute to an understanding of the dissolution mechanism of cellulose in ILs. Finally, we unexpectedly proposed a novel cellulose/IL composite: the cellulose/IL mixtures of 30–50 mol % that possess liquid crystallinity are sufficiently hard to be moldable. MDPI 2017-01-21 /pmc/articles/PMC6155725/ /pubmed/28117730 http://dx.doi.org/10.3390/molecules22010178 Text en © 2017 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
Endo, Takatsugu
Hosomi, Shota
Fujii, Shunsuke
Ninomiya, Kazuaki
Takahashi, Kenji
Nano-Structural Investigation on Cellulose Highly Dissolved in Ionic Liquid: A Small Angle X-ray Scattering Study
title Nano-Structural Investigation on Cellulose Highly Dissolved in Ionic Liquid: A Small Angle X-ray Scattering Study
title_full Nano-Structural Investigation on Cellulose Highly Dissolved in Ionic Liquid: A Small Angle X-ray Scattering Study
title_fullStr Nano-Structural Investigation on Cellulose Highly Dissolved in Ionic Liquid: A Small Angle X-ray Scattering Study
title_full_unstemmed Nano-Structural Investigation on Cellulose Highly Dissolved in Ionic Liquid: A Small Angle X-ray Scattering Study
title_short Nano-Structural Investigation on Cellulose Highly Dissolved in Ionic Liquid: A Small Angle X-ray Scattering Study
title_sort nano-structural investigation on cellulose highly dissolved in ionic liquid: a small angle x-ray scattering study
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6155725/
https://www.ncbi.nlm.nih.gov/pubmed/28117730
http://dx.doi.org/10.3390/molecules22010178
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