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In Situ Observation of Ca2+ Diffusion-Induced Superstructure Formation of a Rigid Polyanion

In situ obervation of Ca2+ diffusion induced superstructure formation of a rigid polyanion.pdf1.02 MBPDF見る/開く

タイトル: In Situ Observation of Ca2+ Diffusion-Induced Superstructure Formation of a Rigid Polyanion
著者: Wu, Zi Liang 著作を一覧する
Takahashi, Riku 著作を一覧する
Sawada, Daisuke 著作を一覧する
Arifuzzaman, Md. 著作を一覧する
Nakajima, Tasuku 著作を一覧する
Kurokawa, Takayuki 著作を一覧する
Hu, Jian 著作を一覧する
Gong, Jian Ping 著作を一覧する
発行日: 2014年10月28日
誌名: Macromolecules
巻: 47
号: 20
開始ページ: 7208
終了ページ: 7214
出版社 DOI: 10.1021/ma501699d
抄録: Diffusion of multivalent metallic ions into aqueous solution of rigid, negatively charged macromolecules of high concentration is an effective approach to prepare macroscopically anisotropic hydrogels. However, the mechanism for superstructure formation is still not clear. By observing the mixing process of a small drop of CaCl2 solution with solution of a rigid polyanion, poly(2,2′- disulfonyl-4,4′-benzidine terephthalamide) (PBDT), under the polarizing optical microscope, the diffusion profile of Ca2+ and detailed anisotropic gelation process of PBDT are revealed. Diffusion of Ca2+ into the surrounding PBDT solution immediately induces the formation of physical liquid crystalline (LC) gel with concentric alignment of PBDT. The thickness d of this region increases with diffusion time t, obeying the diffusion law d ∼ t1/2. A thin ring of constant width (∼100 μm) with radial alignment of PBDT appears at the diffusion/reaction front, ahead of the concentric alignment region. When two drops of CaCl2 fluxes meet, their outside thin rings interact with each other and the PBDT in this contacting region orients ±45° to the midline of the two drops. From these observations, we rationally contend that the internal stress induced by the contraction of gel phase is responsible for the ion diffusion-induced PBDT orientations. This structure formation mechanism gives insight into other diffusion-directed anisotropic gelation systems.
Rights: This document is the Accepted Manuscript version of a Published Work that appeared in final form in Macromolecules, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see
資料タイプ: article (author version)
出現コレクション:雑誌発表論文等 (Peer-reviewed Journal Articles, etc)

提供者: 龔 剣萍 (Gong Jian Ping)


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