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.

在该项目中，化学结构，动力学和机制计划的支持，劳拉·考夫曼（Laura Kaufman）教授以及哥伦比亚大学的博士后同学，研究生和本科研究人员将研究小分子和模拟模型超级冷冻液体中的时空异质性的基本方面。提出的实验将采用一组精心选择的探针分子，以系统地询问各种小分子玻璃玻璃板中异质性的长度和时间尺度。这些测量值将详细说明异质性的空间和时间范围，并可能表明超冷的液体脆性与时空异质性的广度之间存在基本连接。除了典型的超冷液体外，还提出了对具有相似现象学但怀疑具有结构异质性的系统的实验。除了监测单分子（SM）探针旋转动力学的这些测量值外，还将进行直接询问SM水平转移扩散的实验。同时跟踪旋转和翻译将解决有关超冷液体中旋转 - 翻译脱钩现象的问题，从而揭示了这种行为是否可以在单个分子水平上存在。伴随精心制作的模拟将使旋转和翻译运动能够类似于所提出的实验，并将以一种方式来研究和加强对实验结果的解释的方式进行互惠探针 - 宿主相互作用。对超冷液体中的时空异质性有了更深入的了解，从石油运输到细胞的冷冻保存中，对各种领域具有极大的基本兴趣以及对不同领域的应用感兴趣。拟议的工作还将对考夫曼实验室以及年轻学生的本科，研究生和博士后研究人员产生强烈的教育影响。考夫曼教授与当地特许学校建立了关系，向4至6年级的学生提供了关于复杂流体的讲座，与他们的科学老师合作开发了额外的讲座，并将本学校使用的实时评估工具转化为哥伦比亚大学的一般化学课程。通过在哥伦比亚大学的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科学专业的学生和有关联邦机构和基于大学家庭友好政策的教职员工传播信息，并将协助设计，传播和分析哥伦比亚大学的教师使用和对大学的家庭休假政治的研究。