Quantitative Determination of Relative Permittivity Based on the Fluorescence Property of Pyrene Derivatives: An Interpretation of Hydrophobicity in Self-Assembled Aggregates of Nonionic Amphiphiles
Quantitative Determination of Relative Permittivity Based on the Fluorescence Property of Pyrene Derivatives: An Interpretation of Hydrophobicity in Self-Assembled Aggregates of Nonionic Amphiphiles
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DOI：
10.1021/acs.jpcb.1c00170
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发表时间：
2021-06-02
影响因子：
3.3
通讯作者：
Umakoshi, Hiroshi
中科院分区：
文献类型：
--
作者：
Hayashi, Keita;Sugimura, Haruna;Umakoshi, Hiroshi
水溶液中的聚集体可以嵌入疏水分子，它们之间的相互作用取决于聚集体的性质。表面电势、分子流动性和逐渐疏水性是调节相互作用的性质，理解这些性质以量化这些性质是至关重要的。使用zeta电位和NMR测量来量化电表面电位和分子流动性。在这项研究中，逐步疏水性的定量内的相对介电常数，也称为介电常数的基础上的聚集体，已估计从荧光光谱的芘-二羧酸共轭物。芘部分的本地化被修改与琥珀酸，辛二酸，或十二烷二酸的共轭，并在浅，中，深区域的聚集体的共轭物进行了评价。Span和Tween表面活性剂已被用于制备这些聚集体，因为它们形成各种类型的聚集体，如胶束和囊泡。研究发现，从界面到疏水核，疏水性逐渐增加。或者，聚集体内疏水性的比较显示无显著差异。此外，分析表明，在深部区域存在少量水分子。这些结果支持了嵌入分子在聚集体中定位的想法。
Aggregates in aqueous solutions can embed hydrophobic molecules, and their interactions depend on the properties of the aggregates. The electric surface potential, molecular mobility, and gradual hydrophobicity are the properties that regulate the interactions, and it is essential to understand these to quantify the properties. Electric surface potential and molecular mobility are quantified using the zeta potential and NMR measurements. In this study, the quantification of gradual hydrophobicity within the aggregate based on the relative permittivity, also called the dielectric constant, has been estimated from fluorescence spectra of pyrene-dicarboxylic acid conjugates. The localization of the pyrene moiety was modified by conjugation with succinic acid, suberic acid, or dodecanedioic acid, and the conjugates were evaluated in the shallow, middle, and deep regions of the aggregates. Span and Tween surfactants have been employed to prepare these aggregates, because they form various kinds of aggregates such as micelles and vesicles. It was realized that the hydrophobicity gradually increased from the interface to the hydrophobic core. Alternatively, a comparison of hydrophobicity within the aggregates showed no remarkable difference. Moreover, the analyses suggested that there are a few water molecules in the deep region. These results support the idea of the localization of embedded molecules in aggregates.