Nanodroplets to nanoparticles: Integretated studies of freezing

该奖项由化学系的化学结构，动力学和机制计划资助，支持俄亥俄州州立大学的Barbara Wyslouzil教授和她的学生的研究。拟议研究的总体目标是探索冻结的物理学，包括液体可以过冷的极限，转变动力学和新兴固相的结构。这项研究整合了实验和分子建模。 具体的实验目标包括：1）测量液-固成核率作为nanodrophets冻结，2）的分子结构的作用的相对重要性的表面与散装冻结和3）的开发，以跟踪在原位的转换的X射线散射技术的探索。 分子模拟用于理解链状分子中表面冻结的驱动力，并计算液-固成核速率，以直接与测量值进行比较。冻结或从熔体中结晶是一个基本的物理过程，在广泛的工业和自然过程中发挥着核心作用。发展对这一现象的更深入的理解，测量相变速率和探索自由表面在冻结中的作用对于开发工业过程，大气化学和全球气候的精确模型都是至关重要的。在更广泛的背景下，这项工作开发了小角散射，气溶胶光谱学和分子建模技术的新应用，解决了气溶胶科学中的基本问题。这项工作的结果是感兴趣的研究人员在成核，聚合物物理，材料科学，气溶胶和云物理。该计划为学生提供了丰富多样的研究环境，从高中到研究生水平，是高度跨学科的。

This award, funded by the Chemical Structure, Dynamics and Mechanisms program of the Division of Chemistry, supports the research of Prof. Barbara Wyslouzil and her students at The Ohio State University. The overarching goal of the proposed research is to explore the physics of freezing including the limits to which liquids can be supercooled, the transformation kinetics and the structure of the emerging solid phase. This research integrates experimental and molecular modeling. The specific experimental objectives include: 1) measurement of liquid-solid nucleation rates as nanodroplets freeze, 2) the exploration of the role of molecular structure on the relative importance of the surface versus bulk freezing and 3) the development to x-ray scattering techniques to follow the transformations in situ. Molecular modeling is used to understand the driving force for the surface freezing in chain-like molecules and to calculate liquid-solid nucleation rates to compare directly to the measured values. Freezing, or crystallization from the melt, is a fundamental physical process that plays a central role in a broad range of industrial and natural processes. Developing a deeper understanding of this phenomenon, measuring phase transition rates and exploring the role free surfaces play in freezing are all crucial for developing accurate models of industrial processes, atmospheric chemistry and global climate.In a broader context, this work develops novel applications of small angle scattering, aerosol spectroscopy, and molecular modeling techniques that address fundamental problems in aerosol science. The results stemming from this work are of interest to researchers in nucleation, polymer physics, materials science, and aerosol and cloud physics. The program provides a rich and varied research environment for students, from high school to graduate level that is highly interdisciplinary.