Spectroscopic Study on High-Order Structure of Surfactant Molecular Aggregates and Dynamic Interfacial Properties of Meta-Stable Hydrophobic Ultrafine Particle

(a)合成了新型含二甲基硅链段的氟烷基化丙烯酸齐聚物，并研究了它们的溶液性质。这些低聚物在低于其临界胶束浓度的浓度下形成分子聚集体。静态光散射结果表明，聚集体的几何形状不是球形，而是圆柱形。讨论了氟烷基链长和羧基链长对聚集体几何构型的影响。(b)研究了含碳氟链和碳氢链的新型杂化表面活性剂的溶液性质。拉曼光谱研究表明，杂化表面活性剂的聚集状态，特别是烃链的取向，与表面活性剂的浓度密切相关。由于界面张力小，表面活性剂水溶液可以铺展到苯上。研究还发现，复合表面活性剂的浓溶液具有与聚合物溶液相似的粘弹性。(c)研究了超声波作用下形成的纳米级油滴在水中的界面性质。动态光散射测量表明，苯液滴的粒径分布有三个峰值，分别位于30、300和3000nm处。此外，当使用旋转均质器代替超声波浴时，也可以获得小油滴。在此基础上，对油滴的分散和融合机理进行了讨论。

(a) Novel fluoroalkylated acrylic acid oligomers containing dimethylsilicone segments have been synthesized and their solution properties have been studied. These oligomers form molecular aggregates at the concentration lower than their critical micelle concentration. Static light scattering mesurements suggest that the geometry of the aggregates are not spherical, but cylindric. The effect of chain length of fluoroalkyl and carboxyl chains on aggregate geometries are also discussed.(b) Solution properties of novel hybrid surfactants bearing fluorocarbon and hydrocarbon chains in one molecule have been studied. Raman specroscopic measurements show that aggregating condition of the hybrid surfactants, especially orientation of the hydrocarbon chain, is fairly dependent on the surfactant concentration. The surfactant aqueous solution can be spread onto benzene due to small interfacial tension. It is also found that conentrated solution of the hybrid surfactant has viscoelastic property similar to polymer solutions.(c) Interfacial properties of small oil droplets with nanometer size formed by ultrasonication in water have been investigated. Dynamic light scattering measurements show that size distribution of the benzene droplets has three peaks centered at 30, 300 and 3000nm. Furthermore, small oil droplets can be also obtained when a rotary homogenizer is used instead of ultrasonic bath. Mechanism of dispersion and fusion of the oil droplets are discussed based on the obtained results.