Studies on coagulation process of colloidal systems stabilized by adsorption of amphiphilic materials

1.通过介电、超声波、电泳迁移率和阳离子-表面活性剂-吸附实验，研究了不同类型反离子交换蒙脱石粘土悬浮液的水化、吸附和混凝行为。结果表明，表面活性剂的吸附量在加入后的几个小时内达到最大值，然后逐渐下降，接近平衡值。这些结果表明，利用蒙脱石作为吸附剂有效去除废水中的疏水物质时，应考虑吸附动力学。2.研究了几种食品蛋白质和糖基非离子表面活性剂的乳化力和乳化稳定性。牛血清白蛋白（BSA）比β-乳球蛋白（β-Lg）能形成更稳定的玉米油乳状液。在接近BSA等电点的pH 5介质中，当离子强度低于约100时，BSA稳定的乳状液很不稳定。30 mM，但在较高离子强度条件下变得相当稳定。测定了辛基葡萄糖苷、蔗糖月桂酸酯、葡萄糖辛酸酯和阿洛糖辛酸酯水溶液的表面张力随浓度的变化关系，得到了它们的临界胶束浓度和表面过剩量。3.利用原子力显微镜（AFM）测定了阳离子表面活性剂溶液中聚苯乙烯颗粒与硅胶板之间的表面力曲线。证实了双电层排斥力的作用随表面活性剂浓度的增加而增强，并证实了聚合物分子间存在空间位阻力。此外，进行旋涂聚苯乙烯薄膜在水溶液中的椭圆偏振光谱法以估计膜厚度和膜中的水含量。在阳离子表面活性剂溶液中，膜厚度减小，这表明聚苯乙烯分子从界面脱落。

1.Dielectric, ultrasonic velocity, electrophoretic mobility, and cationic-surfactant-adsorption experiments were carried out on suspensions of montmorillonite clay exchanged with different types of counter-ions to understand the hydration, adsorption, and coagulation behaviors of the system. It was found the adsorption amount of surfactants became a maximum in a few hours after the addition and then gradually decreased approaching an equilibrium value. These results suggested that one should consider the kinetics of adsorption for the use of montmorillonite as an adsorbent to remove hydrophobic materials efficiently from waste water.2.Emulsifying power and emulsion stability was investigated for some food proteins and sugar-based nonionic surfactants. Bovine serum albumin (BSA) could form more stable corn oil emulsions than β-lactoglobulin (β-Lg). We also confirmed that in the medium near pH 5 which closed to the iso-electric point of BSA, emulsion stabilized by BSA was quite unstable if ionic strength was below ca. 30 mM, but it became rather stable at higher ionic strength conditions. Surface tension for aqueous solutions of octylglucoside, sucrose laurate, glucose octanoate, and allose octanoate was measured as a function of concentration to get their critical micelle concentration and amount of surface excess.3.Surface force curves between a polystyrene particle and a silica plate both immersed in cationic surfactant solutions were measured by using AFM apparatus. It was confirmed that the effect of repulsive electrical double layer force increased with surfactant concentration and there existed some kind of steric force originated from polymer molecules. Further, spectro-ellipsometry for spin-coat polystyrene thin film in aqueous solutions was performed to estimate the film thickness and water content in the film. In cationic surfactant solutions, the film thickness decreased which suggested coming off of polystyrene molecules from interface.