Janus Particles as Tunable Emulsion Stabilizers

该项目的科学目标是利用具有明确表面组成的Janus颗粒，探索非均相表面功能对乳液形成和稳定性的影响。乳剂在工业生产过程中无处不在，从化妆品到石油化工，对乳剂行为的基本理解是一个多世纪以来研究的主题。传统的乳化工艺采用分子两亲体来稳定油水界面。同样，均质颗粒能够吸附在油水界面以稳定乳状液滴。然而，在许多工业和自然系统中，吸附颗粒在形状或表面化学上并不均匀，而且，尽管许多理论研究已经预测了表面各向异性颗粒的行为，但很少有实验来量化非均质性对界面的影响。研究分三个平行步骤进行。首先，使用均质和非均质颗粒检查乳剂的聚并。其次，研究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与颗粒大小和浓度的关系。第三，探讨了Janus粒子稳定表面的界面结构和流变性，重点研究了界面顺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液稳定性影响的基本方面，并设计出用于稳定多相体系的优化系统。智力优势：本研究的一个主要目标是促进对微米级颗粒的空间非均相表面化学对乳液稳定的影响的理解。该项目的成果可能会影响到广泛的行业，包括原油勘探和分离过程、水净化、下一代制药/个人护理产品。他们在非对称颗粒表面改性、乳液制备、界面性质表征等方面具有丰富的研究经验。此外，pi可以使用(i)表面表征仪器，如扫描电子和原子力显微镜，（ii）乳液，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：乳剂和乳基工艺在工业中的重要性不能被夸大。一系列的学生从高中到研究生水平的培训，在基础和应用方面的乳液技术。此外，国际组成部分使CCNY的学生在本地和国外（哥伦比亚，英国和瑞典）的培训。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骨干方面有着悠久的历史。CCNY是一所公认的少数族裔服务机构，为西班牙裔（36%）、非洲裔（30%）、亚裔（23%）和白人（11%）学生提供多元化的本科服务。此外，个别辅导将为女性和少数族裔学生在职业生涯早期提供一个辅导网络。研究成果将通过期刊出版物、会议和网站广泛传播，并将用于培养高中和本科生的实践经验。

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.