Janus Particles as Tunable Emulsion Stabilizers

奖项：1067501PI：Kretzschmar该项目的科学目标是使用具有明确表面组成的Janus颗粒探索不同表面官能度对乳状液形成和稳定性的影响。乳状液在从化妆品到石油化工的工业过程中无处不在，对乳状液行为的基本了解已经进行了一个多世纪的研究。传统的乳化工艺采用分子两亲性来稳定油水界面。同样，均质颗粒能够吸附到油-水界面以稳定乳化液液滴。然而，在许多工业和自然系统中，吸附的颗粒在形状或表面化学上并不均匀，虽然许多理论研究预测了表面各向异性颗粒的行为，但很少有实验来量化异质性对界面的影响。首先，使用均相颗粒和非均相颗粒考察了乳状液的结合。其次，探讨了均匀颗粒稳定表面的界面结构和流变性，重点研究了界面性质随颗粒大小和浓度的变化规律。第三，探讨了Janus颗粒稳定表面的界面结构和流变性，重点讨论了界面有序在表面力学中的作用。综上所述，这些研究使我们能够了解表面非均质性对乳状液稳定性影响的基本方面，并设计出稳定多相体系的优化体系。智力上的价值：研究的一个主要目标是促进对微米级粒子的空间非均质性表面化学对乳状液稳定性影响的理解。该项目的结果可能会影响广泛的行业，包括原油勘探和分离流程、水净化和下一代药物/个人护理产品。PI在不对称粒子表面改性、乳液制备和界面性质表征方面拥有研究经验。此外，PI还可以使用(I)表面表征仪器，如扫描电子显微镜和原子力显微镜，(Ii)乳化液、流变学和稳定性设备，以及(Iii)表面可视化工具。更广泛的影响：乳液和基于乳液的工艺在工业中的重要性怎么强调都不为过。从高中到研究生水平的一系列学生都接受了乳化液技术的基础和应用方面的培训。此外，国际部分使CCNY学生能够在当地和国外(哥伦比亚、英国和瑞典)接受培训。CCNY的学生通常来自不同的背景，而PI在培养具有广泛背景的学生干部方面有着悠久的历史。CCNY是一家公认的少数族裔服务机构，服务于不同的本科生群体，包括西班牙裔(36%)、非裔美国人(30%)、亚裔(23%)和白人(11%)。此外，个人辅导将在女性和少数族裔学生的职业生涯早期为他们提供一个辅导网络。研究成果将通过期刊出版物、会议和网站广泛传播，并将用于为高中生和本科生发展实践经验。

Award:1067501PI: Kretzschmar The scientific goal of this project is to explore the effect of heterogeneous surface functionality on emulsion formation and stability using Janus particles with well-defined surface compositions. Emulsions are ubiquitous in industrial processes, ranging from cosmetics to petrochemicals, and the fundamental understanding of emulsion behavior has been the subject of over a century of research. Traditional emulsification processes apply molecular amphiphiles to stabilize the oil-water interface. Similarly, homogenous particles are capable of adsorbing to oil-water interfaces to stabilize emulsion droplets. Yet in many industrial and natural systems, the adsorbing particles are not homogenous in shape or surface chemistry, and, while a number of theoretical studies have predicted the behavior of surface anisotropic particles, few experiments have been conducted to quantify the influence of heterogeneities on the interface.The research is carried out in three parallel steps. First, the coalescence of emulsions is examined, using both homogenous and heterogeneous particles. Second, interfacial structure and rheology of surfaces stabilized by homogeneous particles is probed, focusing on the quantification of interfacial properties as a function of particle size and concentration. And third, interfacial structure and rheology of surfaces stabilized by Janus particles are probed, focusing on the role of interfacial order in the mechanics of the surface. Taken together, these studies allow us to understand fundamental aspects of the effect of surface heterogeneities on emulsion stability and engineer optimized systems for stabilizing multiphase systems.Intellectual Merit: A major goal of the research is to advance the understanding of the effect of spatially heterogenous surface chemistry of micron-sized particles on emulsion stabilization. The results of this project are likely to impact a wide range of industries, including crude oil exploration and separation processes, water purification, and next-generation pharmaceutical/personal care products. The PIs have research experience in asymmetric particle surface modification, emulsion preparation, and characterization of interfacial properties. Further, the PIs have access to (i) surface characterization instruments such as scanning electron and atomic force microscopy, (ii) emulsion, rheology, and stability equipment, and (iii) surface visualization tools. Broader Impacts: The importance of emulsions and emulsion-based processes in industry cannot be overstated. A range of students from the high school to the graduate level are trained in both the fundamental and the applied aspects of emulsion technology. Moreover, an international component enables the training of CCNY students locally and abroad (Colombia, England, and Sweden). CCNY students typically come from a diverse background, and the PIs have a long history of training a cadre of students with wide ranging backgrounds. CCNY is a recognized minority serving institution, which serves a diverse undergraduate student body of Hispanic (36%), African American (30%), Asian (23%), and White (11%) students. Further, individual mentoring will provide female and minority students with a mentoring network early on in their careers. Research findings will be broadly disseminated using journal publications, conferences, and websites and will be used to develop hands-on experiences for high school and undergraduate students.