Rotation Diffusion of MOON Particles

这个提案关注的是一个未开发的课题，即胶体颗粒的旋转速度。Kopelman和他的同事最近开发了光学各向异性月球粒子(调制的光学纳米粒子)，为基于这一概念突破的许多有趣的工作奠定了基础。具体而言：(A)任务1：浓缩胶体悬浮液中的平移-旋转脱钩。将在单粒子水平上研究表现为旋转的布朗运动；(B)任务2：以月球粒子为积木的新的和有趣的各向异性胶体结构将显示拟在此处研究的动态重排；(C)任务3：将使用磁场驱动旋转，从而不仅能够进行线性和非线性粘弹性研究，而且在超过屈服强度时，还可以研究粒子与粒子之间的摩擦。这为在单个胶体颗粒水平上研究微观流变学/纳米流变学打开了大门。粒子跟踪对胶体领域产生了巨大的影响，但几乎完全停留在平移运动上。这一提议认为，现在是时候寻求对粒子旋转做同样的事情了。智力上的好处有两个。首先，这将发展对胶体动力学的新理解，胶体动力学在许多科学和技术应用中是基本的，包括涂料、浆料、粉末、原料提取、复合材料和纳米复合材料的机械行为，以及这些材料在其他领域的应用，如催化和能量收集。这项研究将产生新的实验工具来量化粒子动力学，这是传统方法无法表征的。其次，所开发的方法可能会在其他研究小组中得到普遍应用，因为在开发了协议并证明了它们的价值后，它们也应该会找到更广泛的用途。这项工作将把具有单颗粒灵敏度的成像方法引入多相流领域，这些方法在该领域具有特殊的前景。这将通过开发以前不在该学科中使用的新技术来改善多相流领域的研究基础设施。更广泛的影响是将研究与教育相结合。由于这些方法是多相流领域的新方法，它们的使用将实现学科之间的重大智力转移。此外，这些研究生将与化学、化学工程、物理和材料科学的其他学生一起参加一个跨学科研究小组。努力从代表性不足的群体中招收研究生。将要求REU补充，这样本科生就可以参与进来。这个实验室有很好的记录，从一年级开始让女性和西班牙裔本科生研究人员参与，一直持续到获得本科学位，并在这项研究的基础上撰写荣誉论文。本提案详细讨论了该提案将带来的更广泛的影响活动，以及本实验室-S在这一领域的跟踪记录。

0853737GranickThis proposal focuses on an undeveloped subject, how fast colloidal particles rotate. The recent development of optically anisotropic MOON particles (modulated optical nanoparticles) by Kopelman and coworkers sets the stage for much interesting work predicated on this conceptual breakthrough. Specifically: (a) Task 1: Translation-rotation decoupling in concentrated colloidal suspensions. Brownian motion, manifested as rotation, will be studied at the single-particle level.; (b) Task 2: New and interesting anisotropic colloidal structures with MOON particles as building blocks will show dynamical rearrangements proposed to study here; (c) Task 3: Magnetic fields will be used to drive rotation, thus enabling not only linear and nonlinear viscoelastic studies, but also, when a yield strength is exceeded, studies of particle-particle friction. This opens the door to study microrheology/nanorheology at the level of individual colloidal particles. Particle tracking has had a huge impact on the colloid field, yet has dwelt nearly exclusively on translational motion. This proposal argues that the time is right to seek to do the same concerning particle rotation.The intellectual merit is twofold. First, this will develop new understanding of colloidal dynamics, which is fundamental in many scientific and technical applications, including paints, slurries, powders, raw material extraction, the mechanical behavior of composite and nanocomposite materials -- as well as applications of these materials in other fields such as catalysis and energy harvesting. This research will result in new experimental tools to quantify particle dynamics that is impossible to characterize by conventional methods. Second, the methods developed may find general application in other research groups, as they should also find wider utility after protocols have been developed and their value has been demonstrated. This work will import, into the field of multiphase flow, imaging methods with single-particle sensitivity that hold exceptional promise for this field. This will improve research infrastructure in the multiphase flow field by developing new techniques not previously used in this discipline.The broader impact is to integrate research and education. As these methods are new to the field of multiphase flow, their use will accomplish a significant intellectual transfer between disciplines. Furthermore, the graduate students will be part of an interdisciplinary research group with other students from chemistry, chemical engineering, physics, and materials science. Efforts will be made to recruit graduate students from underrepresented groups. An REU supplement will be requested so that undergraduates can be involved. This laboratory has an excellent track record of involving women and Hispanic undergraduate researchers starting in their freshman year, continuing until receiving their undergraduate degree, and writing honors theses based on this research. This proposal discusses at length the broader impact activities that will be enabled by this proposal, as well as this laboratory?s track record in this area.