Elucidating Length and Time Scales of Spatiotemporal Heterogeneity in Supercooled Liquids

阐明过冷液体时空异质性的长度和时间尺度

• 批准号: 1213242
• 负责人: Laura Kaufman
• 金额: $ 45.98万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-09-15 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1213242&HistoricalAwards=false
• 关键词: Elucidating; Length; Time; Scales; Spatiotemporal

In this project supported by the Chemical Structure, Dynamics and Mechanisms Program of the Division of Chemistry, Professor Laura Kaufman, together with her postdoctoral associates, graduate students, and undergraduate researchers at Columbia University will investigate fundamental aspects of spatiotemporal heterogeneity in small molecule and simulated model supercooled liquids. The proposed experiments will employ a set of carefully chosen probe molecules that allow for systematic interrogation of the length and time scales of heterogeneity in a variety of small molecule glass formers. These measurements will detail the spatial and temporal extents of heterogeneity in particular supercooled liquids and may suggest underlying connections between supercooled liquid fragility and breadth of spatiotemporal heterogeneity. Beyond typical supercooled liquids, experiments on systems that display similar phenomenology but are suspected of possessing structural heterogeneity are proposed. In addition to these measurements that monitor single molecule (SM) probe rotational dynamics, experiments that directly interrogate translational diffusion at the SM level will be undertaken. Simultaneous tracking of rotations and translations will resolve questions regarding the poorly understood phenomenon of rotational-translational decoupling in supercooled liquids, revealing whether this behavior can exist on a single molecule level. Accompanying carefully crafted simulations will allow for both rotational and translational motility to be tracked in analogy with the proposed experiments and will investigate reciprocal probe-host interactions in a manner that will inform and strengthen interpretation of experimental results. Achieving a fuller understanding of spatiotemporal heterogeneity in supercooled liquids is of great fundamental interest as well as of applied interest in diverse fields, from petroleum transportation to cryopreservation of cells. The proposed work will also have strong educational impact on undergraduate, graduate, and postdoctoral researchers in the Kaufman laboratory as well as on younger students. Professor Kaufman has initiated a relationship with a local charter school to present lectures on complex fluids to 4th-6th grade students, collaboratively develop additional lectures with their science teacher, and translate real-time assessment tools used in this school into the General Chemistry courses at Columbia University. Through service on Columbia University's Quality of Life Committee, Professor Kaufman will facilitate dissemination of information to Columbia University science students and faculty on federal agency and University-based family friendly policies, and will assist in design, dissemination, and analysis of a study on Columbia University faculty use and perceptions of the University's family leave policies.

在这个由化学系化学结构、动力学和机制项目支持的项目中，劳拉·考夫曼教授及其哥伦比亚大学的博士后、研究生和本科生研究人员将研究小分子和模拟模型过冷液体的时空异质性的基本方面。拟议的实验将采用一组精心选择的探针分子，以便系统地询问各种小分子玻璃形成剂中异质性的长度和时间尺度。这些测量将详细说明特定过冷液体异质性的空间和时间范围，并可能表明过冷液体脆性与时空异质性广度之间的潜在联系。除了典型的过冷液体之外，还提出了对表现出相似现象但怀疑具有结构异质性的系统进行实验。除了这些监测单分子 (SM) 探针旋转动力学的测量之外，还将进行直接询问 SM 水平上平移扩散的实验。同时跟踪旋转和平移将解决人们对过冷液体中旋转平移解耦现象知之甚少的问题，揭示这种行为是否可以存在于单分子水平上。伴随精心设计的模拟将允许与所提出的实验类似地跟踪旋转和平移运动，并将以一种能够告知和加强对实验结果的解释的方式研究相互的探针-宿主相互作用。更全面地了解过冷液体的时空异质性不仅具有重大的根本意义，而且在从石油运输到细胞冷冻保存等不同领域也具有应用意义。拟议的工作还将对考夫曼实验室的本科生、研究生和博士后研究人员以及年轻学生产生强烈的教育影响。考夫曼教授与当地一所特许学校建立了合作关系，向四至六年级的学生提供有关复杂流体的讲座，与他们的科学老师合作开发额外的讲座，并将该学校使用的实时评估工具转化为哥伦比亚大学的普通化学课程。通过在哥伦比亚大学生活质量委员会的服务，考夫曼教授将促进向哥伦比亚大学理科学生和教职员工传播有关联邦机构和大学家庭友好政策的信息，并将协助设计、传播和分析一项关于哥伦比亚大学教职人员使用和对大学家庭休假政策的看法的研究。