Connecting nanoscale structure and dynamics to rheology and flow of glassy nanocolloidal suspensions

将纳米级结构和动力学与玻璃状纳米胶体悬浮液的流变学和流动联系起来

• 批准号: 1336166
• 负责人: Robert Leheny
• 金额: $ 34.98万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-10-01 至 2017-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1336166&HistoricalAwards=false
• 关键词: Connecting; nanoscale; structure; dynamics; rheology

1336166PI: LehenyX-ray photon correlation spectroscopy, in conjunction with other scattering techniques and rheometry, is used to understand microstructural dynamics underlying rheology and flow of three different concentrated nanocolloidal systems: binary mixtures of silica nanocolloids with short-range attractive forces; a depletion-induced colloidal gels; and a nanoemulsion. Data obtained for these systems will provide tests for the generality of the theories for gel-fluid and glass-fluid transitions in colloidal systems and insights into their nonlinear rheology.When sub-micron to nanoscale particles are suspended in a liquid, the resulting composite material, or colloid, can adopt properties of a fluid, a solid, or something in between. In many cases, seemingly subtle changes in the characteristics of the material can dramatically alter its mechanical rigidity and flow behavior. This sensitivity creates both a scientific challenge and an opportunity for designing suspensions with properties tailored for specific applications. Indeed, such control is crucial to a vast range of technologies from 3D printing to food processing and drug delivery. This grant supports a novel avenue of investigation into colloidal suspensions that promises to expand the strategies available for controlling their rigidity and flow, particularly by elucidating the unique properties of suspensions of two sizes of particles with a tendency to stick together that can be tuned. A key feature of the experimental program will be the application of a new x-ray technique that enables unprecedented resolution of the slow microscopic motions in soft materials at lengths as small as a molecule. The development of these x-ray methods for investigating materials under deformation and flow will have impact far beyond the planned experiments by providing a new tool with application that spans several traditional disciplines including physics, chemical engineering, and the biosciences.

1336166 PI：LehenyX射线光子相关光谱，结合其他散射技术和流变学，是用来了解微观结构动力学基础的流变学和流动的三种不同的浓缩纳米胶体系统：二元混合物的二氧化硅纳米胶体与短程吸引力;耗尽诱导的胶体凝胶;和纳米乳液。这些系统获得的数据将提供测试胶体系统中凝胶-流体和玻璃-流体转变理论的普遍性，并深入了解其非线性流变学。当亚微米到纳米级颗粒悬浮在液体中时，所得复合材料或胶体可以采用流体，固体或介于两者之间的性质。 在许多情况下，材料特性中看似细微的变化可以显著改变其机械刚度和流动行为。 这种敏感性为设计具有特定应用特性的悬浮液带来了科学挑战和机会。 事实上，这种控制对于从3D打印到食品加工和药物输送的各种技术都至关重要。 这项资助支持了一种新的研究胶体悬浮液的途径，该途径有望扩大可用于控制其刚度和流动的策略，特别是通过阐明两种尺寸的颗粒悬浮液的独特性质，这些颗粒具有可以调整的粘在一起的趋势。 该实验项目的一个关键特征是应用一种新的X射线技术，该技术能够以前所未有的分辨率对分子大小的软材料中的缓慢微观运动进行研究。 这些用于研究变形和流动下材料的X射线方法的发展将产生远远超出计划实验的影响，提供一种新的工具，其应用范围涵盖物理学，化学工程和生物科学等几个传统学科。