Dynamics of Spontaneous Emulsification in Microchannels

该奖项将研究由油、水和有机溶剂组成的混合物在小范围内的基本多相流动特性。自发乳化现象是指在油-水体系中由于混合溶剂的存在而自然形成液滴的现象，为调整软材料的性能和开发一系列行业的油和水产品的创新处理方法提供了巨大的机会，包括制药、个人护理、食品、能源和环境。虽然人们对纯物质的多相流行为相对了解较多，但对流体添加剂的影响知之甚少，因为流体添加剂会显著改变材料的性质和流动安排。在这里，设计了一套完整的教学和研究活动，旨在解开在混合溶剂存在下的多相流物理，并将新的预测知识发展成一系列具有基本和实际意义的引人入胜的流体现象。该奖项将在一个包容和结构良好的环境中为不同的学生提供广泛的教育机会，原创的外展活动将激发广大公众的好奇心。该奖项将利用先进的微流体协议阐明材料特性和液-液多相流之间的关系。一系列假设驱动的研究将定量地阐明在不相容的液-液多相流中由于添加可混溶的溶剂(如醇)而产生的各种微观输运现象。醇是一类重要的简单有机化合物，可用作萃取剂、防腐剂、洗涤剂、生物燃料、润湿剂、粘度改进剂或乳化剂。这项研究将为改进含醇溶剂的油水多相流的操作奠定科学基础，并表征由于微流几何中界面张力和扩散现象的相互作用而导致的非平衡流体相互作用。对于油包水和水包油的多相流，将在较大的溶剂浓度范围内建立流型特征的函数关系。在超低界面张力下导致胶体分散产生的界面现象将使用表征良好的微观几何和前沿成像和诊断技术，在大范围的长度尺度和时间尺度上有条不紊地获得。流动速度和流体性质的广泛变化将描绘出未知流动状态的重要区域，并为科学发现提供机会。最终，将开发一个通用的、统一的理论框架，以表征液体溶解度在多相流基本原理中的作用。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award will investigate the basic multiphase flow properties of mixtures made of oil, water, and organic solvents at small scales. The phenomenon of spontaneous emulsification refers to the natural formation of droplets due to the presence of a miscible solvent in oil-water systems and offers great opportunities for tailoring the properties of soft materials and developing innovative methods for the treatment of oil and aqueous products in a range of industries, including pharmaceutical, personal care, food, energy, and in the environment. While the multiphase flow behavior of pure substances is relatively well understood, less is known about the influence of fluid additives, which significantly alter material properties and flow arrangements. Here, an integrated suite of teaching and research activities is designed to unravel the physics of multiphase flows in the presence of miscible solvents and develop new predictive knowledge into an array of captivating fluid phenomena of fundamental and practical interests. This award will provide a wide range of educational opportunities for a diversity of students in an inclusive and well-structured environment and original outreach activities will stimulate the curiosity of the public at large.This award will formulate the relationships between material properties and liquid-liquid multiphase flows using advanced microfluidic protocols. A series of hypothesis-driven inquiries will quantitatively elucidate various microscale transport phenomena resulting from the addition of miscible solvents, such as alcohols, in immiscible liquid-liquid multiphase flows. Alcohols compose an important class of simple organic compounds with a myriad of practical uses as extractants, antiseptics, detergents, biofuels, wetting agents, viscosity modifiers, or emulsifiers. The proposed research will lay the scientific foundations for improved manipulations of aqueous-oil multiphase flows with alcohol solvents and characterize out-of-equilibrium fluid interactions resulting from the interplay of interfacial tension and diffusion phenomena in microflow geometries. Functional relationship of flow pattern characteristics will be established across a broad range of solvent concentration for both ‘water-in-oil’ and ‘oil-in-water’ multiphase flows. Interfacial phenomena leading to the generation of colloidal dispersions at ultralow interfacial tension will be methodically accessed over vast ranges of length-scales and timescales using well-characterized microgeometries and leading-edge imaging and diagnostic techniques. Broad variations of flow velocity and fluid properties will delineate significant regions of uncharted flow regimes and enable opportunities for scientific discoveries. Ultimately, a general, unifying theoretical framework will be developed to characterize the role of liquid solubility on the fundamentals of multiphase flows.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.