Wetting Properties of Surfactant Systems

这项研究的目的是从理论和实验两方面研究表面活性剂体系的润湿行为，重点是微乳液。将发展一种新的润湿转变热力学理论，其中将考虑重力的影响，这在这些体系中是重要的。与表面活性剂的结构有关的发生润湿转变的条件也将与本研究一起进行。将使用的实验方法包括新型滴定量热法、动态接触角分析和增强型视频显微镜。一个基于分子热力学的新理论模型将被开发出来，它只依赖于容易测量的参数，允许预测和实验结果的直接比较。本文的研究具有重要的理论意义和现实意义。这将有助于我们从根本上理解表面活性剂体系中的界面现象，以及表面活性剂体系的性质在其中发挥重要作用的众多应用，如提高石油采收率、清净性、液体印刷、微电子学、磁记录介质和新型分离工艺。最近观察到，当一个人离开微乳液体系中的一个临界点时，微乳液相和过剩相之间会发生润湿转变。这种现象只发生在某些表面活性剂中。这项工作将研究表面活性剂结构在润湿转变中的作用。它将侧重于发展微乳液形成的理论模型，该模型将以一种新颖的方式处理界面区域在微乳液形成中的作用。具体地说，界面相的结构将与两相之间的界面张力有关。由于该模型将只包含可测量的热力学参数，因此该模型预测润湿转变的能力将严格测试该模型。本文的研究具有重要的理论意义和现实意义。这将有助于我们从根本上理解表面活性剂体系中的界面现象，以及在许多工程应用中，表面活性剂体系的界面性质起着重要的作用，如提高石油采收率、清净性、液体印刷、微电子学、磁记录介质和新的分离工艺。

The objective of this proposed research is to study both theoretically and experimentally the wetting behavior of surfactant systems, with emphasis on microemulsions. A new thermodynamic theory of wetting transitions will be developed in which the effects of gravity, which are important in these systems, will be taken into account. Conditions under which wetting transitions occur, as related to the structure of the surfactant, will also be undertaken in conjunction with this study. Experimental methods to be used include novel titration calorimetry, dynamic contact angle analysis, and enhanced videomicroscopy. A new theoretical model, based on molecular thermodynamics, will be developed, which relies only on readily measurable parameters, allowing a direct comparison of predictions and experimental results. The proposed research is of both fundamental and practical significance. It will be beneficial to our fundamental understanding of interfacial phenomena in surfactant systems as well as the numerous applications in which the properties of surfactant systems play an important role, such as enhanced oil recovery, detergency, liquid printing, microelectronics, magnetic recording media, and novel separations processes. It has recently been observed that, as one moves away from a critical point in a microemulsion system, a wetting transition can occur between the microemulsion phase and the excess phases. This phenomenon occurs only for some surfactants. The proposed work will investigate the role of surfactant structure in the wetting transition. It will focus on the development of a theoretical model of microemulsion formation which will deal in a novel manner with the role of the interphase region in the formation of microemulsions. Specifically, the structure of the interphase will be related to the interfacial tension between the phases. As the model will contain only measurable thermodynamic parameters, the ability of the model to predict a wetting transition will rigorously test the model. The proposed research is of both fundamental and practical significance. It will be beneficial to our fundamental understanding of interfacial phenomena in surfactant systems as well as to the numerous engineering applications in which the interfacial properties of surfactant systems play an important role, such as enhanced oil recovery, detergency, liquid printing, microelectronics, magnetic recording media, and novel separations processes.