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Molecular self-assembly of nylon-12 nanorods cylindrically confined to nanoporous alumina

Molecular self-assembly of nylon-12 rods in self-organized nanoporous alumina cylinders with two different diameters (65 and 300 nm) is studied with transmission electron microscopy (TEM) and wide-angle X-ray diffraction (WAXD) in symmetrical reflection mode. In a rod with a 300 nm diameter, the ten...

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Autores principales: Cao, Yan, Wu, Hui, Higaki, Yuji, Jinnai, Hiroshi, Takahara, Atsushi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: International Union of Crystallography 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4224462/
https://www.ncbi.nlm.nih.gov/pubmed/25485124
http://dx.doi.org/10.1107/S2052252514020132
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author Cao, Yan
Wu, Hui
Higaki, Yuji
Jinnai, Hiroshi
Takahara, Atsushi
author_facet Cao, Yan
Wu, Hui
Higaki, Yuji
Jinnai, Hiroshi
Takahara, Atsushi
author_sort Cao, Yan
collection PubMed
description Molecular self-assembly of nylon-12 rods in self-organized nanoporous alumina cylinders with two different diameters (65 and 300 nm) is studied with transmission electron microscopy (TEM) and wide-angle X-ray diffraction (WAXD) in symmetrical reflection mode. In a rod with a 300 nm diameter, the tendency of the hydrogen-bonding direction of a γ-form crystal parallel to the long axis of the rod is not clear because of weak two-dimensional confinement. In a rod with a diameter of 65 nm, the tendency of the hydrogen-bonding direction of a γ-form crystal parallel to the long axis of the rod is more distinct because of strong two-dimensional confinement. For the first time, selected-area electron diffraction (SAED) is applied in a transmission electron microscope to a polymer nanorod in order to determine the hydrogen-bond sheet and lamellar orientations. Results of TEM–SAED and WAXD showed that the crystals within the rod possess the γ-form of nylon-12 and that the b axis (stem axis) of the γ-form crystals is perpendicular to the long axis of the rod. These results revealed that only lamellae with 〈h0l〉 directions are able to grow inside the nanopores and the growth of lamellae with 〈hkl〉 (k ≠ 0) directions is stopped owing to impingements against the cylinder walls. The dominant crystal growth direction of the 65 nm rod in stronger two-dimensional confinement is in between the [−201] and [001] directions due to the development of a hydrogen-bonded sheet restricted along the long axis of the rod.
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spelling pubmed-42244622014-12-05 Molecular self-assembly of nylon-12 nanorods cylindrically confined to nanoporous alumina Cao, Yan Wu, Hui Higaki, Yuji Jinnai, Hiroshi Takahara, Atsushi IUCrJ Research Papers Molecular self-assembly of nylon-12 rods in self-organized nanoporous alumina cylinders with two different diameters (65 and 300 nm) is studied with transmission electron microscopy (TEM) and wide-angle X-ray diffraction (WAXD) in symmetrical reflection mode. In a rod with a 300 nm diameter, the tendency of the hydrogen-bonding direction of a γ-form crystal parallel to the long axis of the rod is not clear because of weak two-dimensional confinement. In a rod with a diameter of 65 nm, the tendency of the hydrogen-bonding direction of a γ-form crystal parallel to the long axis of the rod is more distinct because of strong two-dimensional confinement. For the first time, selected-area electron diffraction (SAED) is applied in a transmission electron microscope to a polymer nanorod in order to determine the hydrogen-bond sheet and lamellar orientations. Results of TEM–SAED and WAXD showed that the crystals within the rod possess the γ-form of nylon-12 and that the b axis (stem axis) of the γ-form crystals is perpendicular to the long axis of the rod. These results revealed that only lamellae with 〈h0l〉 directions are able to grow inside the nanopores and the growth of lamellae with 〈hkl〉 (k ≠ 0) directions is stopped owing to impingements against the cylinder walls. The dominant crystal growth direction of the 65 nm rod in stronger two-dimensional confinement is in between the [−201] and [001] directions due to the development of a hydrogen-bonded sheet restricted along the long axis of the rod. International Union of Crystallography 2014-10-21 /pmc/articles/PMC4224462/ /pubmed/25485124 http://dx.doi.org/10.1107/S2052252514020132 Text en © Atsushi Takahara et al. 2014 http://creativecommons.org/licenses/by/2.0/uk/ This is an open-access article distributed under the terms of the Creative Commons Attribution Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
spellingShingle Research Papers
Cao, Yan
Wu, Hui
Higaki, Yuji
Jinnai, Hiroshi
Takahara, Atsushi
Molecular self-assembly of nylon-12 nanorods cylindrically confined to nanoporous alumina
title Molecular self-assembly of nylon-12 nanorods cylindrically confined to nanoporous alumina
title_full Molecular self-assembly of nylon-12 nanorods cylindrically confined to nanoporous alumina
title_fullStr Molecular self-assembly of nylon-12 nanorods cylindrically confined to nanoporous alumina
title_full_unstemmed Molecular self-assembly of nylon-12 nanorods cylindrically confined to nanoporous alumina
title_short Molecular self-assembly of nylon-12 nanorods cylindrically confined to nanoporous alumina
title_sort molecular self-assembly of nylon-12 nanorods cylindrically confined to nanoporous alumina
topic Research Papers
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4224462/
https://www.ncbi.nlm.nih.gov/pubmed/25485124
http://dx.doi.org/10.1107/S2052252514020132
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