Interfacial curvature of surface active substances

本研究提出了一种新的表面活性剂表征参数，即引入特征曲率来描述离子（Cc）和非离子（Ccn）表面活性剂的亲水性和亲脂性。此外，将这些参数引入表面活性剂-油水（SOW）体系的净平均曲率（NAC或NAC- hld）状态方程。NAC-HLD被证明能够预测由阴离子、非离子和阴离子-非离子表面活性剂混合物组成的微乳液聚集体的曲率，这在胶体科学和技术中是第一次。这项拨款申请涉及三个目标，以促进对NAC-HLD状态方程的理解和使用。第一个目标是开发一个“专家系统”，该系统基于NAC-HLD方程，不仅可以预测曲率和界面张力，还可以预测相变、增溶、密度，并结合新的模型来预测聚集体形状、微乳液粘度和乳液稳定性。第二个目标是寻找建立在NAC-HLD模型中的经验关系与分子相互作用之间的联系，这些相互作用由可以表示为曲率项的特征相互作用距离定义。第三个也是最后一个目标涉及到在设计SOW分离方法中使用NAC-HLD模型，特别强调对微乳中增溶和相变的动态方面的研究。该项目包括培训3名博士生（每个目标1名）和8-10名本科生暑期学生，他们将协助目标1和目标3的实验部分。这些研究的预期结果包括一个软件（专家系统），可用于化妆品、药品、洗涤剂、乳化剂和除乳化剂的各种工业过程，包括采油操作。此外，目标3中涉及的新分离工艺可能为使用“绿色溶剂”和不涉及蒸发（高能量投入）的分离工艺生产清洁油品打开大门。

During the current discovery grant a new surfactant characterization parameter, the characteristic curvature was introduced to describe the hydrophilic-lipophilic nature of ionic (Cc) and nonionic (Ccn) surfactants. Furthermore, these parameters were introduced into the Net-Average Curvature (NAC or NAC-HLD) equation of state for surfactant-oil-water (SOW) systems. The NAC-HLD was shown to be able to predict the curvature of microemulsion aggregates formulated with anionic, nonionic and mixtures of anionic-nonionic surfactant mixtures, a first in colloid science and technology. This grant application involves three objectives to advance the understanding and use of the NAC-HLD equation of state. The first objective involves the development of an "expert system" that based on the NAC-HLD equation can predict not only curvature and interfacial tensions, but also phase transitions, solubilization, densities, and incorporate new models to predict aggregate shape, microemulsion viscosity, and emulsion stability. The second objective seeks to find the linkage between the empirical relations built into the NAC-HLD models and molecular interactions, as defined by characteristic interaction distances that can be expressed as curvature terms. The third and final objective involves the use of the NAC-HLD model in designing SOW separation methods, with special emphasis in the study of the dynamic aspects of solubilization and phase transitions in microemulsions. The project involves the training of 3 PhD students (one for each objective) and 8-10 undergraduate summer students who would aid in the experimental components of objectives 1 and 3. The expected outcome of these studies involve a software (expert system) that can be used by formulators of cosmetics, pharmaceuticals, detergents, emulsifiers and de-emulsifiers for various industrial processes, including oil extraction operations. Furthermore, the new separation processes involved in objective 3 may open the door to the use of "green solvents" and of separation processes that do not involve evaporation (high energy input) to produce a clean oil product.