CAREER: Particle-by-Particle Studies of Heterogeneous Dynamics in Molecular and Colloidal Glasses

在这个奖项，由化学系实验物理化学计划资助，教授劳拉考夫曼的哥伦比亚大学，她的博士后研究员和研究生和本科生正在解决系统中的动力学的异构行为的基本方面受到强烈影响的空间或静电拥挤。 小分子玻璃形成剂，模拟模型玻璃态液体，低体积分数胶体玻璃和凝胶正在研究中。 这些系统的异质动力学，本地属性和合作重排正在通过三种技术，避免合奏平均询问。 这些技术是单分子（SM）荧光测量，分子动力学（MD）模拟，相干反斯托克斯拉曼散射（汽车）显微镜。 SM显微镜和MD模拟将澄清（1）如果以及如何探针属性影响测得的探针动力学，（2）这些相同的属性如何潜在地影响主机动态和异质性，以及（3）如何探针轴承实验可以报告的长度尺度的玻璃体系中的异质性。汽车成像将在低体积分数胶体玻璃和凝胶上进行。 在这里，考夫曼小组正在研究这些系统的形成和弛豫动力学是否表现出与高颗粒密度玻璃态环境中相同的异质行为和合作重排。 因为所有的凝聚相系统都以某种方式显示出受拥挤影响的动力学，所以在最明显受影响的系统中研究这些效应可以增加对凝聚相化学的基本理解。 了解玻璃态动力学和防止结晶，在从石油运输到细胞冷冻保存的各种应用中也很重要。 除了这项工作的更广泛的科学影响外，考夫曼教授还为当地小学生举办了关于复杂流体的讲座。 考夫曼教授继续在哥伦比亚大学寻找和指导特别有前途的理科学生。

In this award, funded by the Experimental Physical Chemistry Program of the Division of Chemistry, Professor Laura Kaufman of Columbia University, her postdoctoral fellows and graduate and undergraduate students are addressing fundamental aspects of heterogeneous behavior in systems in which the dynamics are strongly affected by either steric or electrostatic crowding. Small molecule glass formers, simulated model glassy liquids, and low volume fraction colloidal glasses and gels are being investigated. The heterogeneous dynamics, local properties, and cooperative rearrangements of these systems are being interrogated via three techniques that avoid ensemble averaging. These techniques are single molecule (SM) fluorescence measurements, molecular dynamics (MD) simulations, and coherent anti-Stokes Raman scattering (CARS) microscopy. The SM microscopy and MD simulations will clarify (1) if and how probe properties affect measured probe dynamics, (2) how these same properties potentially affect host dynamics and heterogeneities, and (3) how probe bearing experiments can report a length scale of heterogeneity in glassy systems. CARS imaging will be performed on low volume fraction colloidal glasses and gels. Here, the Kaufman group is investigating whether the dynamics of formation and relaxation of these systems exhibit the same sort of heterogeneous behavior and cooperative rearrangements that have been seen in high particle density glassy environments. Because all condensed phase systems display dynamics affected by crowding in some way, studying these effects in the systems most obviously impacted increases fundamental understanding of condensed phase chemistry. Understanding glassy dynamics, and the prevention of crystallization, is also important in diverse applications from petroleum transportation to cryopreservation of cells. Aside from the broader scientific impacts of this work, Professor Kaufman is presenting lectures on complex fluids to local elementary school students. Professor Kaufman continues to identify and mentor especially promising science students at Columbia University.