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，通过密度测量的一部分测量表面张力测量，研究了十二烷基硫酸钠（SDES） - 二甲基三甲基铵（detab）混合物的相位行为。测量表面张力和密度为表面活性剂M的总粒度的功能和detab的组成，在曲线上观察到X.断裂点，并分别确定为临界小囊泡浓度和囊泡 - 米切尔 - 米切尔 - 米切尔共有区域的初始点和最终点的浓度。这些断裂点针对X绘制，对热力学分析，然后将其与简单模型预测的图中的图表进行了比较。从CVC VS X曲线获得了在临界囊泡浓度CVC处的囊泡中的deTAb组成，在几乎x值下发现它为0.5。从另一个断裂点与X图，建议相图中囊泡 - 微粒共存的组成区域为0.62至0.65。此外，即使在x = 0.9999处，囊泡的形成也明确表示，因此，预计临界聚集浓度与X曲线的囊泡 - 丝晶状体过渡介于x = 0.9999和1.2之间。在大气压力下，在各种摩尔度下，测量了二甲基三甲基氨基二硫酸氨基二甲基氨基二甲基氨基甲基氨基的水溶液的表面张力。已经发现驱动是自发形成平衡多层囊泡的。评估了表面密度，吸附的熵和囊泡形成的熵。从热力学的角度以及结果与胶束形成系统的结果进行比较，研究了平衡囊泡的形成机理。