International Research Fellowship Program: Surface Forces Between Two Oil Drops in Aqueous Solutions: Measurements and Interpretation Using Atomic Force Microscopy

国际研究奖学金计划使美国科学家和工程师能够在国外进行三到二十四个月的研究。该计划的奖项提供了联合研究的机会，并利用国外独特或互补的设施、专业知识和实验条件。该奖项将支持Raymond R.Dagastine博士与Franz Grieser博士在澳大利亚维多利亚帕克维尔的墨尔本大学颗粒流体处理中心合作的为期24个月的研究奖学金。该项目的目标是定量研究在各种不同类型乳化剂和表面活性添加剂存在的情况下两个油滴之间的作用力。PI将开发一种使用原子力显微镜(AFM)直接测量这些力的实验方法和解释这些测量的理论框架。这种方法建立在他对单个油滴与刚性探头相互作用之间的测量结果的解释上。工业过程中常见的添加剂和乳化剂通常是两亲性分子，它们在油水界面上分散。吸附到界面上可以是竞争的，也可以是合作的，这些被吸附的物种的流动性的增加可以提供不同于同一物种在固-液界面上吸附的作用力行为。这项工作将提供油水乳状液中添加剂和乳化剂以及液滴间颗粒间的关联，从而深入了解配方、乳状液稳定性和加工过程。了解液-液界面之间的相互作用力对于预测和模拟加工和储存环境中乳状液的稳定性至关重要。在这种情况下，液滴之间的相互吸引会导致乳状液的聚合和相分离。颗粒流体处理中心是墨尔本大学20多年来在胶体和界面科学研究方面处于世界领先地位的项目的一部分。格里泽博士是在液-液界面上进行原子力显微镜测量的领导者。

0202675DagastineThe International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four month research fellowship by Dr. Raymond R. Dagastine to work with Dr. Franz Grieser at the Particulate Fluids Processing Center at the University of Melbourne in Parkville, Victoria, Australia.The goal of this project is to quantitatively study forces between two oil drops in the presence of a variety of different types of emulsifiers and surface-active additives. The PI will develop an experimental approach to measure these forces directly using atomic force microscopy (AFM) and a theoretical framework for interpretation of these measurements. The approach builds on his work on the interpretation of measurements between a single oil drop interacting with a rigid probe. The additives and emulsifiers that are common in industrial processes are commonly amphiphilic molecules, which partition themselves in the oil-water interface. Adsorption to the interface can be competitive or cooperative and the increased mobility of these absorbed species can provide different force behavior than that of the same species absorbed at solid-liquid interfaces. This work will provide correlation between additives and emulsifiers in oil-water emulsions and the interparticle between drops, leading to insight in formulation, emulsion stability, and processing. Understanding of the interaction forces between liquid-liquid interfaces, where attraction between droplets can lead to coalesce and phase separation in emulsions, is vital to predict and model emulsion stability in processing and storage situations.The Particulate Fluids Processing Center is part of the world-leading program in colloidal and interfacial science research that has been established at the University of Melbourne for more than twenty years. Dr. Grieser is a leader in making AFM measurements at liquid-liquid interfaces.