Spontaneous Vesicle Formation and Spontaneous Vesicle-Micelle Transition

自发囊泡形成和自发囊泡-胶束转变

基本信息

批准号：
10440210
负责人：
ARATONO Makoto
金额：
$ 6.34万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

1. The phase behavior of a very dilute aqueous solution of a sodium dodecyl sulfate (SDeS)-decyltrimethylammonium bromide (DeTAB) mixture was investigated by the surface tension measuremnt an partly by the density measurement. The surface tension and density were measured as functions of total molality of surfactant m and composition of DeTAB, X.Break points were observed on the curves and identified as the critical vesicle concentration and the concentration of the initial and final points of the vesicle-micelle coexisting region, respectively. These break points were plotted against X, analyzed thermodynamically, and then the compared with the ones in the diagrams predicted from a simple model. The composition of DeTAB in the vesicle at the critical vesicle concentration, CVC, was obtained from the CVC vs X curve, and it was found out to be 0.5 at almost X values. From the other break point versus X plots, the composition region of the vesicle-micelle coexistence in the phase diagram was suggested to be from 0.62 to 0.65. Furthermore, vesicle formation was clearly indicated to take place even at X=0.9999, and therefore, the vesicle-micelle transition on the critical aggregation concentration versus X curve was expected to sit between X=0.9999 and 1.2. The surface tension of aqueous solution of decyltrimethylammonium decyl sulfate (DeTADeS) was measured as a function of temperature at various molalities under atmospheric pressure. DeTADeS has been found to form equilibrium multilamellar vesicles spontaneously. The surface density, the entropies of adsorption and the entropy of vesicle formation are evaluated. The mechanism of formation of equilibrium vesicle is investigated from the standpoint of thermodynamics and from the comparison of the results with those of the micelle forming systems.

1. 通过表面张力测量和部分密度测量来研究十二烷基硫酸钠 (SDeS)-癸基三甲基溴化铵 (DeTAB) 混合物的非常稀的水溶液的相行为。测量表面张力和密度作为表面活性剂总摩尔浓度 m 和 DeTAB、X 组成的函数。在曲线上观察断点，并将其确定为临界囊泡浓度以及囊泡-胶束起始点和终点的浓度分别为共存区域。这些断点根据 X 绘制，进行热力学分析，然后与从简单模型预测的图表中的断点进行比较。从 CVC vs X 曲线获得临界囊泡浓度 CVC 下囊泡中 DeTAB 的组成，发现在几乎 X 值处为 0.5。从其他断点与 X 图来看，相图中囊泡-胶束共存的组成区域建议为 0.62 至 0.65。此外，清楚地表明即使在X=0.9999时也会发生囊泡形成，因此，临界聚集浓度与X曲线上的囊泡-胶束转变预计位于X=0.9999和1.2之间。在大气压下，测量不同摩尔浓度下癸基三甲基铵癸基硫酸盐 (DeTADeS) 水溶液的表面张力随温度的变化。已发现 DeTADeS 自发形成平衡多层囊泡。评估表面密度、吸附熵和囊泡形成熵。从热力学的角度并通过与胶束形成系统的结果比较来研究平衡囊泡的形成机制。