Electrostatic Interactions During Surfactant Adsorption

虽然对表面活性剂和吸附表面之间的静电相互作用的影响仍知之甚少，但最近有一些研究试图从分子水平上理解表面活性剂的吸附。因此，目前大多数表面活性剂吸附的描述仍然是经验的，因此不能预测。本研究使用最新的理论模型的修改来预测单电荷表面活性剂的吸附，以及实验吸附测量来测试模型的结果。本项目的独特之处在于使用观察到表面活性剂的吸附可以随着表面电荷密度的增加而增加。这一结果可能是由于离子端基与吸附表面之间的静电斥力引起被吸附材料结构的变化。所观察到的吸附行为变化相当大，表明在分子水平上发生了重大变化。通过在表面活性剂吸附对表面电荷密度非常敏感的区域进行实验，在本工作中获得了有关静电相互作用的最大量信息。表面活性材料目前在许多工艺中使用，未来可能会有更广泛的应用。更好地了解表面活性剂的吸附过程的影响是多方面的。目前化学加工的趋势是微工程，在分子水平上控制过程。表面活性剂是获得这种控制的主要手段之一。这项研究的结果可以立即应用于浮选、分散、分离和陶瓷加工等领域，未来还可以应用于微电子领域。

Some attempts to understand surfactant adsorption on the molecular level have recently been reported although the effect of electrostatic interactions between the adsorbing surface and the surfactant are still poorly understood. As a result, most current descriptions of surfactant adsorption remain empirical and thus are not predictive. This investigation uses a modification of the most recent theoretical models to predict the adsorption of singly charged surfactants as well as experimental adsorption measurements to test the results of the modeling. This project is unique in the use of the observation that surfactant adsorption can increase with increasing surface charge density of the same sign. This result may be due to changes in the configuration of the adsorbed materials brought on by electrostatic repulsions between their ionic end groups and the adsorbing surface. The changes in adsorption behavior that have been observed are quite large indicating significant changes at the molecular level. By experimenting in a region where surfactant adsorption is very sensitive to surface charge density, the greatest amount of information about electrostatic interactions is obtained in this work. Surface active materials are used in many processes today and are likely to find even wider application in the future. The impact of a better understanding of the adsorption process for surface active agents is manyfold. Current trends in chemical processing are towards micro-engineering, control of processes at the molecular level. Surfactants are one of the major means of obtaining this control. The results of this investigation could find immediate application in such fields as flotation, dispersion, separations and ceramic processing-- with future applications in microelectronics.