Imanishi Kiyoe, Einaga Yoshiyuki
Department of Chemistry, Nara Women's University, Nara 630-8506, Japan.
J Phys Chem B. 2005 Apr 21;109(15):7574-81. doi: 10.1021/jp044226q.
Wormlike micelles of nonionic surfactants pentaoxyethylene decyl ether C(10)E(5) and hexaoxyethylene decyl ether C(10)E(6) in dilute aqueous solutions were characterized by static (SLS) and dynamic light scattering (DLS) experiments at several temperatures T below the critical points. The SLS results were analyzed with the aid of the molecular thermodynamic theory for SLS from micelle solutions formulated with the wormlike spherocylinder model, thereby yielding the molar mass M(w) of the micelles as a function of c and the cross-sectional diameter d of 2.6 nm for both C(10)E(5) and C(10)E(6) micelles. It has been found that the micelles grow in size with increasing c and T, following the relation M(w) proportional, variant c(1/2) in conformity with the theoretical prediction for highly extended polymerlike micelles. The hydrodynamic radius R(H) of the micelles as a function of M(w) was found to be also well described by the corresponding theories for the wormlike spherocylinder model. The results of the stiffness parameter lambda(-1) show that both micelles are rather stiff compared with those formed with other polyoxyethylene alkyl ethers C(i)E(j) but far from rigid rods. The values of the spacing s between two adjacent hexaoxyethylene chains on the micellar surface were found to be substantially the same for both micelles.
在低于临界点的几个温度(T)下，通过静态光散射（SLS）和动态光散射（DLS）实验对稀水溶液中具有蠕虫状结构的非离子表面活性剂五氧乙烯癸醚(C(10)E(5))和六氧乙烯癸醚(C(10)E(6))进行了表征。借助由蠕虫状球柱体模型构建的胶束溶液的静态光散射分子热力学理论对SLS结果进行了分析，从而得出胶束的摩尔质量(M(w))作为浓度(c)的函数，以及(C(10)E(5))和(C(10)E(6))胶束的横截面直径(d)均为(2.6)纳米。研究发现，胶束尺寸随着(c)和(T)的增加而增大，遵循(M(w))与(c^{1/2})成正比的关系，这与高度伸展的类聚合物胶束的理论预测相符。胶束的流体力学半径(R(H))作为(M(w))的函数，也能用蠕虫状球柱体模型的相应理论很好地描述。刚性参数(\lambda^{-1})的结果表明，与由其他聚氧乙烯烷基醚(C(i)E(j))形成的胶束相比，这两种胶束都相当刚性，但远非刚性棒状。发现两种胶束在胶束表面上两个相邻六氧乙烯链之间的间距(s)值基本相同。
