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ISS: GOALI: Nonequilibrium Processing of Particle Suspensions with Thermal and Electrical Field Gradients

ISS：GOALI：具有热场和电场梯度的颗粒悬浮液的非平衡处理

基本信息

批准号：
1832291
负责人：
Paul Chaikin
金额：
$ 20万
依托单位：
New York University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-01 至 2023-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1832291&HistoricalAwards=false
关键词：
ISS GOALI Nonequilibrium Processing Particle

项目摘要

Colloidal particles are particles with diameters between approximately 1 nanometer and 1 micron. They can be considered as blocks for building materials, like atoms for forming molecules and crystals. In colloidal crystals, the particles are organized in periodic structures with ordering on a range of length scales from nanometers to millimeters or larger. Research on colloidal crystals is motivated by several factors. They can be used to answer fundamental questions related to the assembly of materials, and they have many potential applications in electronics, photonics, and life sciences. However, the rich variety of colloidal crystal structures observed on earth are influenced by the effects of gravity, which leads to particles settling and may lead to motion of the surrounding fluid. In this study, a team of researchers will study colloidal crystal formation in both normal gravity in Earth-based experiments and in microgravity on the International Space Station (ISS). These experiments will reveal the important roles that gravity and external forces play on particle assembly. Ultimately, the researchers will obtain a better understanding of how to manipulate external forces to create colloidal crystals for high resolution 3D printing on Earth and in space. Mechanisms for formation of metastable and glassy phases in particle suspensions will be studied in the ISS and for comparison on Earth. Colloidal particle suspensions are the logical candidates to take advantage of long duration microgravity because (i) they are important for a wide range of terrestrial and space applications, (ii) they share the common feature of coupling between macroscopic particle transport and structure transformations at a particle level and (iii) an adequate explanation for basic features of structure formation in suspensions observed in Earth experiments has not been made to date. Although the time and equipment available for both ground and microgravity experiments is limited, the team of researchers plans to have an impact in many of these areas due to the novel use of field gradients to manipulate the particle density, which is the control parameter for suspensions. Thus, instead of using many different samples to access the interesting range of particle densities, a single sample will be arranged in a field gradient in the sample cell to cover this range. As the particle density is directly measured by microscopy in suspension experiments, a priori knowledge of the gradient profile is not required. The experiments involve setting up the field gradients and observing the resulting structures and then locally mixing a region of known density to watch it glassify or crystallize. Some knowledge of the suspension rheology will come from observations of mixing processes, but quantitative data will come from microrheology measurements through tracking particle thermal motion. The use of colloidal suspensions with real space-time microscopic observations in these studies makes them particularly attractive for teaching students at all levels. We have and will continue to participate in education programs that use space themes to improve interest and skills in STEM, to work with educational professionals to translate the project work to lesson plans for the benefit of students in middle and high school grades and to engage high school and undergraduate students in laboratory work as well as to train and educate undergraduate and graduate students.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.

胶体颗粒是直径在约1纳米和1微米之间的颗粒。它们可以被认为是建筑材料的块，就像形成分子和晶体的原子一样。在胶体晶体中，颗粒以周期性结构组织，在从纳米到毫米或更大的长度尺度范围内有序。胶体晶体的研究受到几个因素的推动。它们可以用来回答与材料组装相关的基本问题，并且在电子学，光子学和生命科学中有许多潜在的应用。然而，在地球上观察到的丰富多样的胶体晶体结构受到重力效应的影响，这导致颗粒沉降，并可能导致周围流体的运动。在这项研究中，一组研究人员将在地球实验中的正常重力和国际空间站（ISS）的微重力下研究胶体晶体的形成。这些实验将揭示重力和外力对粒子组装的重要作用。最终，研究人员将更好地了解如何操纵外力来创建胶体晶体，以便在地球和太空中进行高分辨率3D打印。将在国际空间站研究颗粒悬浮液中亚稳相和玻璃相的形成机制，并在地球上进行比较。胶体颗粒悬浮液是利用长时间微重力的合乎逻辑的候选物，因为（i）它们对于广泛的地面和空间应用很重要，（ii）它们具有在粒子水平上宏观粒子输运和结构转变之间的耦合的共同特征，以及（iii）迄今为止，还没有对地球实验中观察到的悬浮体结构形成的基本特征作出充分的解释。虽然地面和微重力实验的时间和设备有限，但研究人员计划在许多领域产生影响，因为他们新颖地使用场梯度来操纵粒子密度，这是悬浮液的控制参数。因此，代替使用许多不同的样品来访问感兴趣的颗粒密度范围，单个样品将被布置在样品池中的场梯度中以覆盖该范围。由于悬浮液实验中的颗粒密度直接通过显微镜测量，因此不需要梯度分布的先验知识。实验包括设置场梯度和观察产生的结构，然后局部混合一个已知密度的区域，观察它的玻璃化或结晶。悬浮液流变学的一些知识将来自混合过程的观察，但定量数据将来自通过跟踪颗粒热运动的微观流变学测量。在这些研究中使用具有真实的时空显微观察的胶体悬浮液使它们对各级学生的教学特别有吸引力。我们已经并将继续参与利用太空主题来提高STEM兴趣和技能的教育计划，与教育专业人士合作，将项目工作转化为课程计划，使初中和高中年级的学生受益，并让高中和本科生参与实验室工作，以及培训和教育本科生和研究生。该奖项反映了NSF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。