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Molecular level structure analysis of Gibbs film stabilized by interaction between mesoscopic domains

通过介观域之间的相互作用稳定吉布斯薄膜的分子水平结构分析

基本信息

批准号：
16550017
负责人：
TAKIUE Takanori
金额：
$ 2.3万
依托单位：
KYUSHU UNIVERCITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

Recent development of spectroscopic technique enables us to analyze the structure of interfacial films at gas/liquid interfaces from molecular level. However, the structure analysis of interfacial films at liquid/liquid interfaces has not been well organized yet, although it gives fundamental information about the structure and property of molecular organized systems such as microemulsion, vesicles, biomembranes, and so on. This study aim at elucidating the relationship between function and structure in biological system on the basis of structure analysis of Gibbs films at liquid/liquid interfaces.During the research for three years, the Gibbs films of fluorocarbon (FC) and hydrocarbon (HC) alcohols at the hexane/water interface was examined by interfacial tension and synchrotron X-ray reflectivity measurements. The noticeable results obtained are as follows.1. Interfacial tension studyThe interfacial tensions of the hexane solution of solutes against water were measured as a function … More of temperature, pressure, and concentration. The experimental data was analyzed in terms of rigorous thermodynamics of interfaces to obtain interfacial density, entropy and volume of adsorption, phase diagram of adsorption, and excess thermodynamic quantities of adsorption.(1) The adsorbed FC alcohol films exhibit phase transition between gaseous (or expanded) and condensed states.(2) FC alcohols mix with HC alcohol in the expanded film, while are immiscible in the condensed film because of very weak mutual interaction between FC and HC chains.(3) FC alcohols become to be miscible with cationic surfactant with HC chain (DTAB) due to strong attractive interaction of hydroxyl group with cationic head group.(4) In the mixed system of FC alcohol-DTAB, Gibbs film form multilayer spontaneously.2. X-ray reflectivity studyIn order to determine the structure of Gibbs films found in the interfacial tension study, the X-ray reflectivity measurements were performed at BL-X19C in NSLS of Brookhaven National Laboratory (USA) as a function of temperature at fixed concentration. The results obtained were ;(1) FC and HC alcohols are closely packed in the condensed film like two-dimensional solid state.(2) The Gibbs films are inhomogeneous by coexisting condensed phase domains with very low density gaseous film near phase transition temperature.(3) The total reflectivity in the condensed film is lower for FC alcohol-DTAB system is lower than for the condensed films of single FC alcohol systems. This suggests the mixing of FC alcohol and DTAB in the condensed state.(4) The oscillation of reflectivity curve supports the multilayer formation in the FC alcohol-DTAB system. Less

光谱技术的最新发展使我们能够从分子水平分析气/液界面处的界面膜结构。然而，液/液界面的界面膜结构分析尚未得到很好的组织，尽管它提供了有关微乳液、囊泡、生物膜等分子组织系统的结构和性质的基本信息。本研究旨在通过对液/液界面吉布斯膜的结构分析来阐明生物系统中功能与结构的关系。在三年的研究过程中，通过界面张力和同步加速器X射线反射率测量来研究正己烷/水界面处的氟碳(FC)和碳氢(HC)醇的吉布斯膜。取得的显著成果如下： 1．界面张力研究溶质的己烷溶液相对于水的界面张力是作为温度、压力和浓度的函数来测量的。对实验数据进行严格的界面热力学分析，得到界面密度、吸附熵和体积、吸附相图以及吸附过剩热力学量。(1)吸附的FC醇膜表现出气态(或膨胀)和凝聚态之间的相变。(2)FC醇与HC醇在膨胀膜中混合，同时由于FC和HC链之间的相互作用非常弱，在缩合膜中不互溶。（3）由于羟基与阳离子头基的强烈吸引力相互作用，FC醇与带HC链的阳离子表面活性剂（DTAB）混溶。（4）在FC醇-DTAB混合体系中，吉布斯膜自发形成多层。2． X 射线反射率研究为了确定界面张力研究中发现的吉布斯薄膜的结构，在布鲁克海文国家实验室（美国）的 NSLS 的 BL-X19C 上进行了 X 射线反射率测量，作为固定浓度下温度的函数。结果表明：（1）FC和HC醇紧密堆积在凝聚膜中，呈二维固态。（2）在相变温度附近，Gibbs膜由于凝聚相域与极低密度气态膜共存而呈现不均匀性。（3）FC醇-DTAB体系凝聚膜的总反射率低于单一FC醇体系凝聚膜的总反射率。这表明FC醇和DTAB在冷凝状态下混合。(4)反射率曲线的振荡支持了FC醇-DTAB体系中多层膜的形成。较少的