CAREER: High-speed 3D Imaging of Colloidal Self-Assembly with Digital Holographic Microscopy

职业：利用数字全息显微镜对胶体自组装进行高速 3D 成像

• 批准号: 0747625
• 负责人: Vinothan Manoharan
• 金额: $ 44.97万
• 依托单位: Harvard University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-02-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0747625&HistoricalAwards=false
• 关键词: CAREER; speed; 3D; Imaging; Colloidal

0747625ManoharanThe primary goal of the PI's proposed research is to investigate how colloidal particles self-assemble in confined and nonequilibrium systems, including particles trapped at liquid-liquid interfaces (e.g. emulsion droplets) and inside spherical containers. Although common in industrial formulations and fundamental condensed matter studies, these systems remain poorly understood, primarily because no existing experimental probes, including confocal microscopy, can yield real-space data with sufficiently fast acquisition times to resolve 3D dynamics. The PI proposes to use a powerful interferometric technique, Digital Holographic Microscopy (DHM), in concert with particle synthesis and algorithm development to overcome these limitations. Preliminary data show that the technique is capable of tracking several micrometer-sized colloidal particles with 30 nm spatial precision in all three dimensions on millisecond time scales. DHM may be able to yield the most complete physical picture to date of dynamics, interactions, and assembly in colloidal suspensions. Intellectual MeritThe proposed research seeks to answer fundamental questions in colloid science by pursuing the following objectives: 1. Development and optimization of a Digital Holographic Microscope to investigate colloidal suspensions: A prototype of this instrument has been constructed and preliminary data are shown. The PI will develop new algorithms, data acquisition techniques, and instrumentation to make the technique as rapid and robust as possible. 2. Use of this instrument in the following experimental studies: ? Measuring the dynamics of particles trapped at planar liquid-liquid interfaces: determining the interactions governing the assembly of interfacially-bound particles. ? Measuring the dynamics and structure of particles trapped at spherical liquid-liquid interfaces: investigating the self-assembled structures of particles confined to an emulsion interface. ? Imaging self-assembly in dense colloids confined inside an interface: Determining the effect of a spherical droplet boundary on the structure and assembly of colloidal crystallites. Broader ImpactsThis work will benefit industrial product development by providing a rational framework for the formulation of multiphase colloidal systems. It will also yield insights into structure formation in complex fluids that may be useful in nanofabrication. In addition, an integrated education and outreach program will target 8th grade science students in the Cambridge school district, a diverse and urban school system with a majority of students from underrepresented minority groups and low-income households. Goals of the program are: 1. Developing a design module to engage at-risk 8th grade science students: The PI will work closely with a teacher from the Kennedy-Longfellow middle school to develop, implement, and assess an inquiry-based learning program that (a) meets Massachusetts standards for teaching physics and engineering in 8th grade and (b) targets all skill groups, including Special Education students. Harvard undergraduate volunteers from the new School of Engineering and Applied Sciences will be recruited as mentors and facilitators. The broader aim is to educate and engage more middle school students through mentorship, research, and open-ended design projects. 2. Undergraduate education through research and mentoring; graduate course development

0747625 Manoharan PI提出的研究的主要目标是研究胶体颗粒如何在受限和非平衡系统中自组装，包括在液-液界面（例如乳液液滴）和球形容器内捕获的颗粒。虽然常见的工业配方和基本凝聚态研究，这些系统仍然知之甚少，主要是因为没有现有的实验探针，包括共聚焦显微镜，可以产生真实空间数据与足够快的采集时间来解决三维动态。PI建议使用强大的干涉技术，数字全息显微镜（DHM），与粒子合成和算法开发相结合，以克服这些限制。初步数据显示，该技术能够在毫秒时间尺度上以30 nm的空间精度在所有三个维度上跟踪几个微米大小的胶体颗粒。DHM可能能够产生最完整的物理图片的动力学，相互作用和组装在胶体悬浮液的日期。智力价值拟议的研究旨在回答胶体科学的基本问题，追求以下目标：1。数字全息显微镜的发展和优化研究胶体悬浮液：该仪器的原型已经建成，并显示了初步数据。PI将开发新的算法，数据采集技术和仪器，使该技术尽可能快速和强大。 2.在以下实验研究中使用该仪器：测量平面液-液界面处捕获粒子的动力学：确定控制界面结合粒子组装的相互作用。 ?测量在球形液-液界面捕获的颗粒的动力学和结构：研究局限于乳状液界面的颗粒的自组装结构。 ?在界面内致密胶体中成像自组装：确定球形液滴边界对胶体微晶结构和组装的影响。更广泛的影响这项工作将有利于工业产品的开发，提供了一个合理的框架，制定多相胶体系统。它还将产生对复杂流体中的结构形成的见解，这可能在纳米纤维中有用。此外，一个综合教育和推广方案将针对剑桥学区的8年级理科学生，这是一个多样化的城市学校系统，大部分学生来自代表性不足的少数群体和低收入家庭。该计划的目标是：1。开发一个设计模块，以吸引处于风险中的8年级理科学生：PI将与一名来自兰迪-朗费罗中学的教师密切合作，开发、实施和评估一个基于探究的学习计划，该计划（a）符合马萨诸塞州8年级物理和工程教学标准，（B）针对所有技能群体，包括特殊教育学生。来自新的工程与应用科学学院的哈佛本科生志愿者将被招募为导师和促进者。更广泛的目标是通过指导，研究和开放式设计项目教育和吸引更多的中学生。 2.通过研究和指导进行本科教育;研究生课程开发