CAREER: Interrogating dense anisotropic colloidal suspensions with SMR-TIRM

纳米级到微米级的“胶体”颗粒存在于消费品、涂料和自然界中。例如，油漆、油墨和润滑剂含有这种大小的颗粒，它们被设计成在液体中很好地分散。然而，颗粒可能以降低性能的方式沉积或聚集。对于非球形或具有不均匀表面化学性质的颗粒，很难预测这些不利过程。首席研究员将开发并应用一种实验技术来揭示控制这些复杂颗粒沉积或聚集的物理和化学力。研究结果将改变我们对先进涂层、多相材料和生物膜粘附的理解。此外，PI还将组织由高中生、本科生和研究生组成的团队，通过暑期体验项目探索消费品、纺织品、化妆品和食品的世界。该计划包括实验室和课堂经验，最终将开发大学水平的课程，教学工具和案例研究，并在整个俄亥俄州传播。该职业奖整合了研究和教育目标，以改变我们对各向异性胶体颗粒如何与涂层加工界面相互作用的理解，多相材料的生产，以及对合成和生物活性胶体的理解。这项工作的研究目的是测量具有形状和表面化学各向异性的胶体密集悬浮液的保守和非保守表面相互作用。目前完成这项工作的瓶颈是现有的表面相互作用测量技术要么不适合这样的系统，要么不够敏感。PI将开发一种称为散射形态分辨全内反射显微镜（SMR-TIRM）的工具。SMR-TIRM的工作原理是利用胶体粒子的倏逝波散射的形态波动，而不是综合强度波动。PI将使用SMR-TIRM来量化驱动胶体中对称破缺的性质，以及表面相互作用对刚性和非刚性界面附近各向异性粒子拥挤的依赖。这项研究将为各向异性胶体粒子如何与表面相互作用提供重要信息。教育目标是建立一个体验式项目，将大学活动与校园STEM高中的活动结合起来，该高中是克利夫兰大都会学区的一部分。该计划的主题将是胶体和界面科学在化学产品设计中的应用。该项目将包括一个大学水平的化学产品设计课程，一个基于项目的高中学生体验式学习计划，以及一个培养高中学生、本科生和研究生多层次项目团队的研究经验，这些团队被安排在克利夫兰州立大学新的共享软材料实验室。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nanometer to micrometer scale "colloidal" particles are found in consumer products, coatings, and nature. For example, paints, inks, and lubricants contain particles of this size that are designed to be well-dispersed in a liquid. However, particles may deposit or aggregate in ways that diminish performance. It is difficult to predict these unfavorable processes for particles that are non-spherical or have non-uniform surface chemistry. The principal investigator will develop and apply an experimental technique to reveal the physical and chemical forces controlling the deposition or aggregation of these complex particles. The results should transform our understanding of advanced coatings, multiphase materials, and biofilm adhesion. In addition, the PI will form teams of high school, undergraduate, and graduate students to explore the world of consumer products, textiles, cosmetics, and food through an experiential summer program. The program consists of laboratory and in-class experiences that will culminate in the development of a college-level course, teaching tools, and case studies to be disseminated throughout Ohio. This CAREER award integrates research and educational objectives to transform our understanding of how anisotropic colloidal particles interact with interfaces for the processing of coatings, production of multiphase materials, and understanding of synthetic and biological active colloids. The research objective of this work is to measure conservative and non-conservative surface interactions for dense suspensions of colloids with anisotropy in both shape and surface chemistry. The current bottleneck to completing this work is that existing surface interaction measurement techniques are either not suitable for such systems or are not sufficiently sensitive. The PI will develop a tool called Scattering Morphology Resolved Total Internal Reflection Microscopy (SMR-TIRM). SMR-TIRM works by utilizing fluctuations in the morphology of evanescent wave scattering from a colloidal particle, rather than the integrated intensity fluctuations. The PI will use SMR-TIRM to quantify the nature of symmetry breaking in driven colloids and the dependence of surface interactions on crowding of anisotropic particles near rigid and non-rigid interfaces. This research will provide crucial information for how anisotropic colloidal particles interact with surfaces. The education objective is to build an experiential program that integrates university activities with those at an on-campus STEM high school, which is part of the Cleveland Metropolitan School District. The theme of the program will be applications of Colloid and Interface Science in the design of chemical products. The program will consist of a college-level course in Chemical Product Design, a project based experiential learning program for high school students, and a research experience fostering multi-level project teams of high school students, undergraduates, and graduate students housed in the new shared Soft Materials Lab at Cleveland State University.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.