Hierarchical Structure of Supramolecular Polymers Formed by N,N鈥?Di(2-ethylhexyl)urea in Solutions

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• 作者：Jolanta 艢wiergiel ; Laurent Bouteiller ; Jan Jad偶yn
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：October 8, 2015
• 年：2015
• 卷：119
• 期：40
• 页码：12947-12953
• 全文大小：463K
• ISSN：1520-5207

文摘

Supramolecular chain polymers formed by N,N鈥?di(2-ethylhexyl)urea (EHU) dissolved at low concentrations (up to 0.1 mole fraction) in heptane were investigated with the use of the dielectric spectroscopy. The experimental data show an exceptional ability of the chains for the antiparallel self-aggregation due to dipole鈥揹ipole interactions, leading to an anomalous dependence of the static permittivity of EHU + heptane solutions on temperature and concentration of the urea. The primary molecular assembly into polymeric chains is therefore followed by a secondary bundling of the chains which facilitates a longitudinal translation of the chains. That peculiarity and an asymmetry of the alkyl substituent in the EHU molecule making the system a mixture of diastereoisomers of unfavorable packing of the side group, are the most probable molecular mechanisms which prevent the crystallization of EHU鈥攖he only known liquid urea derivative.