Collaborative Research: Microrheology of colloidal glasses and gels

合作研究：胶体玻璃和凝胶的微观流变学

• 批准号: 1236242
• 负责人: John Brady
• 金额: $ 16.24万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1236242&HistoricalAwards=false
• 关键词: Collaborative; Research; Microrheology; colloidal; glasses

1235955 / 1236242PI: Furst / BradyWhy and how do colloidal gels form? What is the relationship between gels and glasses, states that occur when particles crowd each other to the point of dynamic arrest? There is long-running debate regarding the mechanism of colloidal gelation, particularly at moderate to high particle volume fractions and relatively weak attractive interactions. The aim of this work is to investigate the microrheology of colloidal glasses and gels to determine whether there is a direct relation between these states. The work is accomplished through the development of optical trapping experiments and Stokesian dynamics simulations that measure the response of individual probe particles in colloidal suspensions. Since theories of colloidal glasses and gels are microrheological, but few studies to date have examined and attempted to validate these theories on microscopic length scales, such work is timely.Colloidal gels are an arrested, non-equilibrium state of matter that impact shelf life of consumer care products, agrochemicals, coatings, pigments and inks?potentially any product or material in which particles are suspended at high concentration in a fluid phase. Moreover, glasses and gels are ubiquitous states of matter in molecular, macromolecular and colloidal materials. The insights gained under this project have broad implications for our fundamental understanding of many materials. Through an integrated education and professional training of graduate students from underrepresented backgrounds in STEM disciplines and outreach activities involving undergraduate research experiences and research experiences for teachers, this work enhances the capacity for US innovation in the chemical and advanced materials industries.

1235955 / 1236242PI：Furst / Brady 胶体凝胶为何以及如何形成？ 凝胶和玻璃之间有什么关系，当粒子彼此拥挤到动态停止点时会出现什么状态？ 关于胶体凝胶化的机制存在长期争论，特别是在中等到高颗粒体积分数和相对较弱的吸引相互作用的情况下。这项工作的目的是研究胶体玻璃和凝胶的微观流变学，以确定这些状态之间是否存在直接关系。这项工作是通过开发光学捕获实验和斯托克斯动力学模拟来测量胶体悬浮液中单个探针颗粒的响应而完成的。 由于胶体玻璃和凝胶的理论是微流变学的，但迄今为止很少有研究在微观长度尺度上检验并试图验证这些理论，因此这样的工作是及时的。胶体凝胶是一种停滞的、非平衡的物质状态，会影响保质期消费者护理产品、农用化学品、涂料、颜料和油墨——可能是颗粒以高浓度悬浮在流体相中的任何产品或材料。此外，玻璃和凝胶是分子、大分子和胶体材料中普遍存在的物质状态。在这个项目中获得的见解对于我们对许多材料的基本理解具有广泛的影响。通过对来自 STEM 学科背景的研究生进行综合教育和专业培训，以及涉及本科生研究经验和教师研究经验的推广活动，这项工作增强了美国在化学和先进材料行业的创新能力。